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diff --git a/contrib/ncurses/doc/html/NCURSES-Programming-HOWTO.html b/contrib/ncurses/doc/html/NCURSES-Programming-HOWTO.html new file mode 100644 index 0000000..3a10106 --- /dev/null +++ b/contrib/ncurses/doc/html/NCURSES-Programming-HOWTO.html @@ -0,0 +1,6413 @@ +<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> +<html> +<head> +<meta name="generator" content= +"HTML Tidy for Linux/x86 (vers 1st December 2004), see www.w3.org"> +<title>NCURSES Programming HOWTO</title> +<meta name="GENERATOR" content= +"Modular DocBook HTML Stylesheet Version 1.7"> +</head> +<body class="ARTICLE" bgcolor="#FFFFFF" text="#000000" link= +"#0000FF" vlink="#840084" alink="#0000FF"> +<div class="ARTICLE"> +<div class="TITLEPAGE"> +<h1 class="TITLE"><a name="AEN2" id="AEN2">NCURSES Programming +HOWTO</a></h1> +<h3 class="AUTHOR"><a name="AEN4" id="AEN4">Pradeep Padala</a></h3> +<div class="AFFILIATION"> +<div class="ADDRESS"> +<p class="ADDRESS"><code class="EMAIL"><<a href= +"mailto:ppadala@gmail.com">ppadala@gmail.com</a>></code></p> +</div> +</div> +<p class="PUBDATE">v1.9, 2005-06-20<br></p> +<div class="REVHISTORY"> +<table width="100%" border="0"> +<tr> +<th align="left" valign="top" colspan="3"><b>Revision +History</b></th> +</tr> +<tr> +<td align="left">Revision 1.9</td> +<td align="left">2005-06-20</td> +<td align="left">Revised by: ppadala</td> +</tr> +<tr> +<td align="left" colspan="3">The license has been changed to the +MIT-style license used by NCURSES. Note that the programs are also +re-licensed under this.</td> +</tr> +<tr> +<td align="left">Revision 1.8</td> +<td align="left">2005-06-17</td> +<td align="left">Revised by: ppadala</td> +</tr> +<tr> +<td align="left" colspan="3">Lots of updates. Added references and +perl examples. Changes to examples. Many grammatical and stylistic +changes to the content. Changes to NCURSES history.</td> +</tr> +<tr> +<td align="left">Revision 1.7.1</td> +<td align="left">2002-06-25</td> +<td align="left">Revised by: ppadala</td> +</tr> +<tr> +<td align="left" colspan="3">Added a README file for building and +instructions for building from source.</td> +</tr> +<tr> +<td align="left">Revision 1.7</td> +<td align="left">2002-06-25</td> +<td align="left">Revised by: ppadala</td> +</tr> +<tr> +<td align="left" colspan="3">Added "Other formats" section and made +a lot of fancy changes to the programs. Inlining of programs is +gone.</td> +</tr> +<tr> +<td align="left">Revision 1.6.1</td> +<td align="left">2002-02-24</td> +<td align="left">Revised by: ppadala</td> +</tr> +<tr> +<td align="left" colspan="3">Removed the old Changelog section, +cleaned the makefiles</td> +</tr> +<tr> +<td align="left">Revision 1.6</td> +<td align="left">2002-02-16</td> +<td align="left">Revised by: ppadala</td> +</tr> +<tr> +<td align="left" colspan="3">Corrected a lot of spelling mistakes, +added ACS variables section</td> +</tr> +<tr> +<td align="left">Revision 1.5</td> +<td align="left">2002-01-05</td> +<td align="left">Revised by: ppadala</td> +</tr> +<tr> +<td align="left" colspan="3">Changed structure to present proper +TOC</td> +</tr> +<tr> +<td align="left">Revision 1.3.1</td> +<td align="left">2001-07-26</td> +<td align="left">Revised by: ppadala</td> +</tr> +<tr> +<td align="left" colspan="3">Corrected maintainers paragraph, +Corrected stable release number</td> +</tr> +<tr> +<td align="left">Revision 1.3</td> +<td align="left">2001-07-24</td> +<td align="left">Revised by: ppadala</td> +</tr> +<tr> +<td align="left" colspan="3">Added copyright notices to main +document (LDP license) and programs (GPL), Corrected +printw_example.</td> +</tr> +<tr> +<td align="left">Revision 1.2</td> +<td align="left">2001-06-05</td> +<td align="left">Revised by: ppadala</td> +</tr> +<tr> +<td align="left" colspan="3">Incorporated ravi's changes. Mainly to +introduction, menu, form, justforfun sections</td> +</tr> +<tr> +<td align="left">Revision 1.1</td> +<td align="left">2001-05-22</td> +<td align="left">Revised by: ppadala</td> +</tr> +<tr> +<td align="left" colspan="3">Added "a word about window" section, +Added scanw_example.</td> +</tr> +</table> +</div> +<div> +<div class="ABSTRACT"><a name="AEN67" id="AEN67"></a> +<p><em>This document is intended to be an "All in One" guide for +programming with ncurses and its sister libraries. We graduate from +a simple "Hello World" program to more complex form manipulation. +No prior experience in ncurses is assumed. Send comments to +<a href="mailto:ppadala@gmail.com" target="_top">this +address</a></em></p> +</div> +</div> +<hr></div> +<div class="TOC"> +<dl> +<dt><b>Table of Contents</b></dt> +<dt>1. <a href="#INTRO">Introduction</a></dt> +<dd> +<dl> +<dt>1.1. <a href="#WHATIS">What is NCURSES?</a></dt> +<dt>1.2. <a href="#WHATCANWEDO">What we can do with +NCURSES</a></dt> +<dt>1.3. <a href="#WHERETOGETIT">Where to get it</a></dt> +<dt>1.4. <a href="#PURPOSE">Purpose/Scope of the document</a></dt> +<dt>1.5. <a href="#ABOUTPROGRAMS">About the Programs</a></dt> +<dt>1.6. <a href="#OTHERFORMATS">Other Formats of the +document</a></dt> +<dt>1.7. <a href="#CREDITS">Credits</a></dt> +<dt>1.8. <a href="#WISHLIST">Wish List</a></dt> +<dt>1.9. <a href="#COPYRIGHT">Copyright</a></dt> +</dl> +</dd> +<dt>2. <a href="#HELLOWORLD">Hello World !!!</a></dt> +<dd> +<dl> +<dt>2.1. <a href="#COMPILECURSES">Compiling With the NCURSES +Library</a></dt> +<dt>2.2. <a href="#DISSECTION">Dissection</a></dt> +</dl> +</dd> +<dt>3. <a href="#GORY">The Gory Details</a></dt> +<dt>4. <a href="#INIT">Initialization</a></dt> +<dd> +<dl> +<dt>4.1. <a href="#ABOUTINIT">Initialization functions</a></dt> +<dt>4.2. <a href="#RAWCBREAK">raw() and cbreak()</a></dt> +<dt>4.3. <a href="#ECHONOECHO">echo() and noecho()</a></dt> +<dt>4.4. <a href="#KEYPAD">keypad()</a></dt> +<dt>4.5. <a href="#HALFDELAY">halfdelay()</a></dt> +<dt>4.6. <a href="#MISCINIT">Miscellaneous Initialization +functions</a></dt> +<dt>4.7. <a href="#INITEX">An Example</a></dt> +</dl> +</dd> +<dt>5. <a href="#AWORDWINDOWS">A Word about Windows</a></dt> +<dt>6. <a href="#PRINTW">Output functions</a></dt> +<dd> +<dl> +<dt>6.1. <a href="#ADDCHCLASS">addch() class of functions</a></dt> +<dt>6.2. <a href="#AEN298">mvaddch(), waddch() and +mvwaddch()</a></dt> +<dt>6.3. <a href="#PRINTWCLASS">printw() class of +functions</a></dt> +<dt>6.4. <a href="#ADDSTRCLASS">addstr() class of +functions</a></dt> +<dt>6.5. <a href="#ACAUTION">A word of caution</a></dt> +</dl> +</dd> +<dt>7. <a href="#SCANW">Input functions</a></dt> +<dd> +<dl> +<dt>7.1. <a href="#GETCHCLASS">getch() class of functions</a></dt> +<dt>7.2. <a href="#SCANWCLASS">scanw() class of functions</a></dt> +<dt>7.3. <a href="#GETSTRCLASS">getstr() class of +functions</a></dt> +<dt>7.4. <a href="#GETSTREX">Some examples</a></dt> +</dl> +</dd> +<dt>8. <a href="#ATTRIB">Attributes</a></dt> +<dd> +<dl> +<dt>8.1. <a href="#ATTRIBDETAILS">The details</a></dt> +<dt>8.2. <a href="#ATTRONVSATTRSET">attron() vs attrset()</a></dt> +<dt>8.3. <a href="#ATTR_GET">attr_get()</a></dt> +<dt>8.4. <a href="#ATTR_FUNCS">attr_ functions</a></dt> +<dt>8.5. <a href="#WATTRFUNCS">wattr functions</a></dt> +<dt>8.6. <a href="#CHGAT">chgat() functions</a></dt> +</dl> +</dd> +<dt>9. <a href="#WINDOWS">Windows</a></dt> +<dd> +<dl> +<dt>9.1. <a href="#WINDOWBASICS">The basics</a></dt> +<dt>9.2. <a href="#LETBEWINDOW">Let there be a Window !!!</a></dt> +<dt>9.3. <a href="#BORDEREXEXPL">Explanation</a></dt> +<dt>9.4. <a href="#OTHERSTUFF">The other stuff in the +example</a></dt> +<dt>9.5. <a href="#OTHERBORDERFUNCS">Other Border +functions</a></dt> +</dl> +</dd> +<dt>10. <a href="#COLOR">Colors</a></dt> +<dd> +<dl> +<dt>10.1. <a href="#COLORBASICS">The basics</a></dt> +<dt>10.2. <a href="#CHANGECOLORDEFS">Changing Color +Definitions</a></dt> +<dt>10.3. <a href="#COLORCONTENT">Color Content</a></dt> +</dl> +</dd> +<dt>11. <a href="#KEYS">Interfacing with the key board</a></dt> +<dd> +<dl> +<dt>11.1. <a href="#KEYSBASICS">The Basics</a></dt> +<dt>11.2. <a href="#SIMPLEKEYEX">A Simple Key Usage +example</a></dt> +</dl> +</dd> +<dt>12. <a href="#MOUSE">Interfacing with the mouse</a></dt> +<dd> +<dl> +<dt>12.1. <a href="#MOUSEBASICS">The Basics</a></dt> +<dt>12.2. <a href="#GETTINGEVENTS">Getting the events</a></dt> +<dt>12.3. <a href="#MOUSETOGETHER">Putting it all Together</a></dt> +<dt>12.4. <a href="#MISCMOUSEFUNCS">Miscellaneous +Functions</a></dt> +</dl> +</dd> +<dt>13. <a href="#SCREEN">Screen Manipulation</a></dt> +<dd> +<dl> +<dt>13.1. <a href="#GETYX">getyx() functions</a></dt> +<dt>13.2. <a href="#SCREENDUMP">Screen Dumping</a></dt> +<dt>13.3. <a href="#WINDOWDUMP">Window Dumping</a></dt> +</dl> +</dd> +<dt>14. <a href="#MISC">Miscellaneous features</a></dt> +<dd> +<dl> +<dt>14.1. <a href="#CURSSET">curs_set()</a></dt> +<dt>14.2. <a href="#TEMPLEAVE">Temporarily Leaving Curses +mode</a></dt> +<dt>14.3. <a href="#ACSVARS">ACS_ variables</a></dt> +</dl> +</dd> +<dt>15. <a href="#OTHERLIB">Other libraries</a></dt> +<dt>16. <a href="#PANELS">Panel Library</a></dt> +<dd> +<dl> +<dt>16.1. <a href="#PANELBASICS">The Basics</a></dt> +<dt>16.2. <a href="#COMPILEPANELS">Compiling With the Panels +Library</a></dt> +<dt>16.3. <a href="#PANELBROWSING">Panel Window Browsing</a></dt> +<dt>16.4. <a href="#USERPTRUSING">Using User Pointers</a></dt> +<dt>16.5. <a href="#PANELMOVERESIZE">Moving and Resizing +Panels</a></dt> +<dt>16.6. <a href="#PANELSHOWHIDE">Hiding and Showing +Panels</a></dt> +<dt>16.7. <a href="#PANELABOVE">panel_above() and panel_below() +Functions</a></dt> +</dl> +</dd> +<dt>17. <a href="#MENUS">Menus Library</a></dt> +<dd> +<dl> +<dt>17.1. <a href="#MENUBASICS">The Basics</a></dt> +<dt>17.2. <a href="#COMPILEMENUS">Compiling With the Menu +Library</a></dt> +<dt>17.3. <a href="#MENUDRIVER">Menu Driver: The work horse of the +menu system</a></dt> +<dt>17.4. <a href="#MENUWINDOWS">Menu Windows</a></dt> +<dt>17.5. <a href="#SCROLLMENUS">Scrolling Menus</a></dt> +<dt>17.6. <a href="#MULTICOLUMN">Multi Columnar Menus</a></dt> +<dt>17.7. <a href="#MULTIVALUEMENUS">Multi Valued Menus</a></dt> +<dt>17.8. <a href="#MENUOPT">Menu Options</a></dt> +<dt>17.9. <a href="#MENUUSERPTR">The useful User Pointer</a></dt> +</dl> +</dd> +<dt>18. <a href="#FORMS">Forms Library</a></dt> +<dd> +<dl> +<dt>18.1. <a href="#FORMBASICS">The Basics</a></dt> +<dt>18.2. <a href="#COMPILEFORMS">Compiling With the Forms +Library</a></dt> +<dt>18.3. <a href="#PLAYFIELDS">Playing with Fields</a></dt> +<dt>18.4. <a href="#FORMWINDOWS">Form Windows</a></dt> +<dt>18.5. <a href="#FILEDVALIDATE">Field Validation</a></dt> +<dt>18.6. <a href="#FORMDRIVER">Form Driver: The work horse of the +forms system</a></dt> +</dl> +</dd> +<dt>19. <a href="#TOOLS">Tools and Widget Libraries</a></dt> +<dd> +<dl> +<dt>19.1. <a href="#CDK">CDK (Curses Development Kit)</a></dt> +<dt>19.2. <a href="#DIALOG">The dialog</a></dt> +<dt>19.3. <a href="#PERLCURSES">Perl Curses Modules CURSES::FORM +and CURSES::WIDGETS</a></dt> +</dl> +</dd> +<dt>20. <a href="#JUSTFORFUN">Just For Fun !!!</a></dt> +<dd> +<dl> +<dt>20.1. <a href="#GAMEOFLIFE">The Game of Life</a></dt> +<dt>20.2. <a href="#MAGIC">Magic Square</a></dt> +<dt>20.3. <a href="#HANOI">Towers of Hanoi</a></dt> +<dt>20.4. <a href="#QUEENS">Queens Puzzle</a></dt> +<dt>20.5. <a href="#SHUFFLE">Shuffle</a></dt> +<dt>20.6. <a href="#TT">Typing Tutor</a></dt> +</dl> +</dd> +<dt>21. <a href="#REF">References</a></dt> +</dl> +</div> +<div class="SECT1"> +<h2 class="SECT1"><a name="INTRO" id="INTRO">1. +Introduction</a></h2> +<p>In the olden days of teletype terminals, terminals were away +from computers and were connected to them through serial cables. +The terminals could be configured by sending a series of bytes. All +the capabilities (such as moving the cursor to a new location, +erasing part of the screen, scrolling the screen, changing modes +etc.) of terminals could be accessed through these series of bytes. +These control seeuqnces are usually called escape sequences, +because they start with an escape(0x1B) character. Even today, with +proper emulation, we can send escape sequences to the emulator and +achieve the same effect on a terminal window.</p> +<p>Suppose you wanted to print a line in color. Try typing this on +your console.</p> +<table border="0" bgcolor="#E0E0E0" width="100%"> +<tr> +<td> +<pre class="PROGRAMLISTING"> +<font color="#000000">echo "^[[0;31;40mIn Color"</font> +</pre></td> +</tr> +</table> +<p>The first character is an escape character, which looks like two +characters ^ and [. To be able to print it, you have to press +CTRL+V and then the ESC key. All the others are normal printable +characters. You should be able to see the string "In Color" in red. +It stays that way and to revert back to the original mode type +this.</p> +<table border="0" bgcolor="#E0E0E0" width="100%"> +<tr> +<td> +<pre class="PROGRAMLISTING"> +<font color="#000000">echo "^[[0;37;40m"</font> +</pre></td> +</tr> +</table> +<p>Now, what do these magic characters mean? Difficult to +comprehend? They might even be different for different terminals. +So the designers of UNIX invented a mechanism named <var class= +"LITERAL">termcap</var>. It is a file that lists all the +capabilities of a particular terminal, along with the escape +sequences needed to achieve a particular effect. In the later +years, this was replaced by <var class="LITERAL">terminfo</var>. +Without delving too much into details, this mechanism allows +application programs to query the terminfo database and obtain the +control characters to be sent to a terminal or terminal +emulator.</p> +<div class="SECT2"> +<hr> +<h3 class="SECT2"><a name="WHATIS" id="WHATIS">1.1. What is +NCURSES?</a></h3> +<p>You might be wondering, what the import of all this technical +gibberish is. In the above scenario, every application program is +supposed to query the terminfo and perform the necessary stuff +(sending control characters etc.). It soon became difficult to +manage this complexity and this gave birth to 'CURSES'. Curses is a +pun on the name "cursor optimization". The Curses library forms a +wrapper over working with raw terminal codes, and provides highly +flexible and efficient API (Application Programming Interface). It +provides functions to move the cursor, create windows, produce +colors, play with mouse etc. The application programs need not +worry about the underlying terminal capabilities.</p> +<p>So what is NCURSES? NCURSES is a clone of the original System V +Release 4.0 (SVr4) curses. It is a freely distributable library, +fully compatible with older version of curses. In short, it is a +library of functions that manages an application's display on +character-cell terminals. In the remainder of the document, the +terms curses and ncurses are used interchangeably.</p> +<p>A detailed history of NCURSES can be found in the NEWS file from +the source distribution. The current package is maintained by +<a href="mailto:dickey@his.com" target="_top">Thomas Dickey</a>. +You can contact the maintainers at <a href= +"mailto:bug-ncurses@gnu.org" target= +"_top">bug-ncurses@gnu.org</a>.</p> +</div> +<div class="SECT2"> +<hr> +<h3 class="SECT2"><a name="WHATCANWEDO" id="WHATCANWEDO">1.2. What +we can do with NCURSES</a></h3> +<p>NCURSES not only creates a wrapper over terminal capabilities, +but also gives a robust framework to create nice looking UI (User +Interface)s in text mode. It provides functions to create windows +etc. Its sister libraries panel, menu and form provide an extension +to the basic curses library. These libraries usually come along +with curses. One can create applications that contain multiple +windows, menus, panels and forms. Windows can be managed +independently, can provide 'scrollability' and even can be +hidden.</p> +<p>Menus provide the user with an easy command selection option. +Forms allow the creation of easy-to-use data entry and display +windows. Panels extend the capabilities of ncurses to deal with +overlapping and stacked windows.</p> +<p>These are just some of the basic things we can do with ncurses. +As we move along, We will see all the capabilities of these +libraries.</p> +</div> +<div class="SECT2"> +<hr> +<h3 class="SECT2"><a name="WHERETOGETIT" id="WHERETOGETIT">1.3. +Where to get it</a></h3> +<p>All right, now that you know what you can do with ncurses, you +must be rearing to get started. NCURSES is usually shipped with +your installation. In case you don't have the library or want to +compile it on your own, read on.</p> +<p><em>Compiling the package</em></p> +<p>NCURSES can be obtained from <a href= +"ftp://ftp.gnu.org/pub/gnu/ncurses/ncurses.tar.gz" target= +"_top">ftp://ftp.gnu.org/pub/gnu/ncurses/ncurses.tar.gz</a> or any +of the ftp sites mentioned in <a href= +"http://www.gnu.org/order/ftp.html" target= +"_top">http://www.gnu.org/order/ftp.html</a>.</p> +<p>Read the README and INSTALL files for details on to how to +install it. It usually involves the following operations.</p> +<table border="0" bgcolor="#E0E0E0" width="100%"> +<tr> +<td> +<pre class="PROGRAMLISTING"> +<font color= +"#000000"> tar zxvf ncurses<version>.tar.gz # unzip and untar the archive + cd ncurses<version> # cd to the directory + ./configure # configure the build according to your + # environment + make # make it + su root # become root + make install # install it</font> +</pre></td> +</tr> +</table> +<p><em>Using the RPM</em></p> +<p>NCURSES RPM can be found and downloaded from <a href= +"http://rpmfind.net" target="_top">http://rpmfind.net</a> . The RPM +can be installed with the following command after becoming +root.</p> +<table border="0" bgcolor="#E0E0E0" width="100%"> +<tr> +<td> +<pre class="PROGRAMLISTING"> +<font color="#000000"> rpm -i <downloaded rpm></font> +</pre></td> +</tr> +</table> +</div> +<div class="SECT2"> +<hr> +<h3 class="SECT2"><a name="PURPOSE" id="PURPOSE">1.4. Purpose/Scope +of the document</a></h3> +<p>This document is intended to be a "All in One" guide for +programming with ncurses and its sister libraries. We graduate from +a simple "Hello World" program to more complex form manipulation. +No prior experience in ncurses is assumed. The writing is informal, +but a lot of detail is provided for each of the examples.</p> +</div> +<div class="SECT2"> +<hr> +<h3 class="SECT2"><a name="ABOUTPROGRAMS" id="ABOUTPROGRAMS">1.5. +About the Programs</a></h3> +<p>All the programs in the document are available in zipped form +<a href= +"http://www.tldp.org/HOWTO/NCURSES-Programming-HOWTO/ncurses_programs.tar.gz" +target="_top">here</a>. Unzip and untar it. The directory structure +looks like this.</p> +<table border="0" bgcolor="#E0E0E0" width="100%"> +<tr> +<td> +<pre class="PROGRAMLISTING"> +<font color="#000000">ncurses + | + |----> JustForFun -- just for fun programs + |----> basics -- basic programs + |----> demo -- output files go into this directory after make + | | + | |----> exe -- exe files of all example programs + |----> forms -- programs related to form library + |----> menus -- programs related to menus library + |----> panels -- programs related to panels library + |----> perl -- perl equivalents of the examples (contributed + | by Anuradha Ratnaweera) + |----> Makefile -- the top level Makefile + |----> README -- the top level README file. contains instructions + |----> COPYING -- copyright notice</font> +</pre></td> +</tr> +</table> +<p>The individual directories contain the following files.</p> +<table border="0" bgcolor="#E0E0E0" width="100%"> +<tr> +<td> +<pre class="PROGRAMLISTING"> +<font color="#000000">Description of files in each directory +-------------------------------------- +JustForFun + | + |----> hanoi.c -- The Towers of Hanoi Solver + |----> life.c -- The Game of Life demo + |----> magic.c -- An Odd Order Magic Square builder + |----> queens.c -- The famous N-Queens Solver + |----> shuffle.c -- A fun game, if you have time to kill + |----> tt.c -- A very trivial typing tutor + + basics + | + |----> acs_vars.c -- ACS_ variables example + |----> hello_world.c -- Simple "Hello World" Program + |----> init_func_example.c -- Initialization functions example + |----> key_code.c -- Shows the scan code of the key pressed + |----> mouse_menu.c -- A menu accessible by mouse + |----> other_border.c -- Shows usage of other border functions apa + | -- rt from box() + |----> printw_example.c -- A very simple printw() example + |----> scanw_example.c -- A very simple getstr() example + |----> simple_attr.c -- A program that can print a c file with + | -- comments in attribute + |----> simple_color.c -- A simple example demonstrating colors + |----> simple_key.c -- A menu accessible with keyboard UP, DOWN + | -- arrows + |----> temp_leave.c -- Demonstrates temporarily leaving curses mode + |----> win_border.c -- Shows Creation of windows and borders + |----> with_chgat.c -- chgat() usage example + + forms + | + |----> form_attrib.c -- Usage of field attributes + |----> form_options.c -- Usage of field options + |----> form_simple.c -- A simple form example + |----> form_win.c -- Demo of windows associated with forms + + menus + | + |----> menu_attrib.c -- Usage of menu attributes + |----> menu_item_data.c -- Usage of item_name() etc.. functions + |----> menu_multi_column.c -- Creates multi columnar menus + |----> menu_scroll.c -- Demonstrates scrolling capability of menus + |----> menu_simple.c -- A simple menu accessed by arrow keys + |----> menu_toggle.c -- Creates multi valued menus and explains + | -- REQ_TOGGLE_ITEM + |----> menu_userptr.c -- Usage of user pointer + |----> menu_win.c -- Demo of windows associated with menus + + panels + | + |----> panel_browse.c -- Panel browsing through tab. Usage of user + | -- pointer + |----> panel_hide.c -- Hiding and Un hiding of panels + |----> panel_resize.c -- Moving and resizing of panels + |----> panel_simple.c -- A simple panel example + + perl + |----> 01-10.pl -- Perl equivalents of first ten example programs</font> +</pre></td> +</tr> +</table> +<p>There is a top level Makefile included in the main directory. It +builds all the files and puts the ready-to-use exes in demo/exe +directory. You can also do selective make by going into the +corresponding directory. Each directory contains a README file +explaining the purpose of each c file in the directory.</p> +<p>For every example, I have included path name for the file +relative to the examples directory.</p> +<p>If you prefer browsing individual programs, point your browser +to <a href= +"http://tldp.org/HOWTO/NCURSES-Programming-HOWTO/ncurses_programs/" +target= +"_top">http://tldp.org/HOWTO/NCURSES-Programming-HOWTO/ncurses_programs/</a></p> +<p>All the programs are released under the same license that is +used by ncurses (MIT-style). This gives you the ability to do +pretty much anything other than claiming them as yours. Feel free +to use them in your programs as appropriate.</p> +</div> +<div class="SECT2"> +<hr> +<h3 class="SECT2"><a name="OTHERFORMATS" id="OTHERFORMATS">1.6. +Other Formats of the document</a></h3> +<p>This howto is also availabe in various other formats on the +tldp.org site. Here are the links to other formats of this +document.</p> +<div class="SECT3"> +<hr> +<h4 class="SECT3"><a name="LISTFORMATS" id="LISTFORMATS">1.6.1. +Readily available formats from tldp.org</a></h4> +<ul> +<li> +<p><a href= +"http://www.ibiblio.org/pub/Linux/docs/HOWTO/other-formats/pdf/NCURSES-Programming-HOWTO.pdf" +target="_top">Acrobat PDF Format</a></p> +</li> +<li> +<p><a href= +"http://www.ibiblio.org/pub/Linux/docs/HOWTO/other-formats/ps/NCURSES-Programming-HOWTO.ps.gz" +target="_top">PostScript Format</a></p> +</li> +<li> +<p><a href= +"http://www.ibiblio.org/pub/Linux/docs/HOWTO/other-formats/html/NCURSES-Programming-HOWTO-html.tar.gz" +target="_top">In Multiple HTML pages</a></p> +</li> +<li> +<p><a href= +"http://www.ibiblio.org/pub/Linux/docs/HOWTO/other-formats/html_single/NCURSES-Programming-HOWTO.html" +target="_top">In One big HTML format</a></p> +</li> +</ul> +</div> +<div class="SECT3"> +<hr> +<h4 class="SECT3"><a name="BUILDSOURCE" id="BUILDSOURCE">1.6.2. +Building from source</a></h4> +<p>If above links are broken or if you want to experiment with sgml +read on.</p> +<table border="0" bgcolor="#E0E0E0" width="100%"> +<tr> +<td> +<pre class="PROGRAMLISTING"> +<font color= +"#000000"> Get both the source and the tar,gzipped programs, available at + http://cvsview.tldp.org/index.cgi/LDP/howto/docbook/ + NCURSES-HOWTO/NCURSES-Programming-HOWTO.sgml + http://cvsview.tldp.org/index.cgi/LDP/howto/docbook/ + NCURSES-HOWTO/ncurses_programs.tar.gz + + Unzip ncurses_programs.tar.gz with + tar zxvf ncurses_programs.tar.gz + + Use jade to create various formats. For example if you just want to create + the multiple html files, you would use + jade -t sgml -i html -d <path to docbook html stylesheet> + NCURSES-Programming-HOWTO.sgml + to get pdf, first create a single html file of the HOWTO with + jade -t sgml -i html -d <path to docbook html stylesheet> -V nochunks + NCURSES-Programming-HOWTO.sgml > NCURSES-ONE-BIG-FILE.html + then use htmldoc to get pdf file with + htmldoc --size universal -t pdf --firstpage p1 -f <output file name.pdf> + NCURSES-ONE-BIG-FILE.html + for ps, you would use + htmldoc --size universal -t ps --firstpage p1 -f <output file name.ps> + NCURSES-ONE-BIG-FILE.html</font> +</pre></td> +</tr> +</table> +<p>See <a href="http://www.tldp.org/LDP/LDP-Author-Guide/" target= +"_top">LDP Author guide</a> for more details. If all else failes, +mail me at <a href="ppadala@gmail.com" target= +"_top">ppadala@gmail.com</a></p> +</div> +</div> +<div class="SECT2"> +<hr> +<h3 class="SECT2"><a name="CREDITS" id="CREDITS">1.7. +Credits</a></h3> +<p>I thank <a href="mailto:sharath_1@usa.net" target= +"_top">Sharath</a> and Emre Akbas for helping me with few sections. +The introduction was initially written by sharath. I rewrote it +with few excerpts taken from his initial work. Emre helped in +writing printw and scanw sections.</p> +<p>Perl equivalents of the example programs are contributed by +<a href="mailto:Aratnaweera@virtusa.com" target="_top">Anuradha +Ratnaweera</a>.</p> +<p>Then comes <a href="mailto:parimi@ece.arizona.edu" target= +"_top">Ravi Parimi</a>, my dearest friend, who has been on this +project before even one line was written. He constantly bombarded +me with suggestions and patiently reviewed the whole text. He also +checked each program on Linux and Solaris.</p> +</div> +<div class="SECT2"> +<hr> +<h3 class="SECT2"><a name="WISHLIST" id="WISHLIST">1.8. Wish +List</a></h3> +<p>This is the wish list, in the order of priority. If you have a +wish or you want to work on completing the wish, mail <a href= +"mailto:ppadala@gmail.com" target="_top">me</a>.</p> +<ul> +<li> +<p>Add examples to last parts of forms section.</p> +</li> +<li> +<p>Prepare a Demo showing all the programs and allow the user to +browse through description of each program. Let the user compile +and see the program in action. A dialog based interface is +preferred.</p> +</li> +<li> +<p>Add debug info. _tracef, _tracemouse stuff.</p> +</li> +<li> +<p>Accessing termcap, terminfo using functions provided by ncurses +package.</p> +</li> +<li> +<p>Working on two terminals simultaneously.</p> +</li> +<li> +<p>Add more stuff to miscellaneous section.</p> +</li> +</ul> +</div> +<div class="SECT2"> +<hr> +<h3 class="SECT2"><a name="COPYRIGHT" id="COPYRIGHT">1.9. +Copyright</a></h3> +<p>Copyright © 2001 by Pradeep Padala.</p> +<p>Permission is hereby granted, free of charge, to any person +obtaining a copy of this software and associated documentation +files (the "Software"), to deal in the Software without +restriction, including without limitation the rights to use, copy, +modify, merge, publish, distribute, distribute with modifications, +sublicense, and/or sell copies of the Software, and to permit +persons to whom the Software is furnished to do so, subject to the +following conditions:</p> +<p>The above copyright notice and this permission notice shall be +included in all copies or substantial portions of the Software.</p> +<p>THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, +EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF +MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND +NONINFRINGEMENT. IN NO EVENT SHALL THE ABOVE COPYRIGHT HOLDERS BE +LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN +ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN +CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE +SOFTWARE.</p> +<p>Except as contained in this notice, the name(s) of the above +copyright holders shall not be used in advertising or otherwise to +promote the sale, use or other dealings in this Software without +prior written authorization.</p> +</div> +</div> +<div class="SECT1"> +<hr> +<h2 class="SECT1"><a name="HELLOWORLD" id="HELLOWORLD">2. Hello +World !!!</a></h2> +<p>Welcome to the world of curses. Before we plunge into the +library and look into its various features, let's write a simple +program and say hello to the world.</p> +<div class="SECT2"> +<hr> +<h3 class="SECT2"><a name="COMPILECURSES" id="COMPILECURSES">2.1. +Compiling With the NCURSES Library</a></h3> +<p>To use ncurses library functions, you have to include ncurses.h +in your programs. To link the program with ncurses the flag +-lncurses should be added.</p> +<table border="0" bgcolor="#E0E0E0" width="100%"> +<tr> +<td> +<pre class="PROGRAMLISTING"> +<font color="#000000"> #include <ncurses.h> + . + . + . + + compile and link: gcc <program file> -lncurses</font> +</pre></td> +</tr> +</table> +<div class="EXAMPLE"><a name="BHW" id="BHW"></a> +<p><b>Example 1. The Hello World !!! Program</b></p> +<table border="0" bgcolor="#E0E0E0" width="100%"> +<tr> +<td> +<pre class="PROGRAMLISTING"> +<font color="#000000"><span class= +"INLINEMEDIAOBJECT">#include <ncurses.h> + +int main() +{ + initscr(); /* Start curses mode */ + printw("Hello World !!!"); /* Print Hello World */ + refresh(); /* Print it on to the real screen */ + getch(); /* Wait for user input */ + endwin(); /* End curses mode */ + + return 0; +}</span></font> +</pre></td> +</tr> +</table> +</div> +</div> +<div class="SECT2"> +<hr> +<h3 class="SECT2"><a name="DISSECTION" id="DISSECTION">2.2. +Dissection</a></h3> +<p>The above program prints "Hello World !!!" to the screen and +exits. This program shows how to initialize curses and do screen +manipulation and end curses mode. Let's dissect it line by +line.</p> +<div class="SECT3"> +<hr> +<h4 class="SECT3"><a name="ABOUT-INITSCR" id="ABOUT-INITSCR">2.2.1. +About initscr()</a></h4> +<p>The function initscr() initializes the terminal in curses mode. +In some implementations, it clears the screen and presents a blank +screen. To do any screen manipulation using curses package this has +to be called first. This function initializes the curses system and +allocates memory for our present window (called <var class= +"LITERAL">stdscr</var>) and some other data-structures. Under +extreme cases this function might fail due to insufficient memory +to allocate memory for curses library's data structures.</p> +<p>After this is done, we can do a variety of initializations to +customize our curses settings. These details will be explained +<a href="#INIT">later</a> .</p> +</div> +<div class="SECT3"> +<hr> +<h4 class="SECT3"><a name="MYST-REFRESH" id="MYST-REFRESH">2.2.2. +The mysterious refresh()</a></h4> +<p>The next line printw prints the string "Hello World !!!" on to +the screen. This function is analogous to normal printf in all +respects except that it prints the data on a window called stdscr +at the current (y,x) co-ordinates. Since our present co-ordinates +are at 0,0 the string is printed at the left hand corner of the +window.</p> +<p>This brings us to that mysterious refresh(). Well, when we +called printw the data is actually written to an imaginary window, +which is not updated on the screen yet. The job of printw is to +update a few flags and data structures and write the data to a +buffer corresponding to stdscr. In order to show it on the screen, +we need to call refresh() and tell the curses system to dump the +contents on the screen.</p> +<p>The philosophy behind all this is to allow the programmer to do +multiple updates on the imaginary screen or windows and do a +refresh once all his screen update is done. refresh() checks the +window and updates only the portion which has been changed. This +improves performance and offers greater flexibility too. But, it is +sometimes frustrating to beginners. A common mistake committed by +beginners is to forget to call refresh() after they did some update +through printw() class of functions. I still forget to add it +sometimes :-)</p> +</div> +<div class="SECT3"> +<hr> +<h4 class="SECT3"><a name="ABOUT-ENDWIN" id="ABOUT-ENDWIN">2.2.3. +About endwin()</a></h4> +<p>And finally don't forget to end the curses mode. Otherwise your +terminal might behave strangely after the program quits. endwin() +frees the memory taken by curses sub-system and its data structures +and puts the terminal in normal mode. This function must be called +after you are done with the curses mode.</p> +</div> +</div> +</div> +<div class="SECT1"> +<hr> +<h2 class="SECT1"><a name="GORY" id="GORY">3. The Gory +Details</a></h2> +<p>Now that we have seen how to write a simple curses program let's +get into the details. There are many functions that help customize +what you see on screen and many features which can be put to full +use.</p> +<p>Here we go...</p> +</div> +<div class="SECT1"> +<hr> +<h2 class="SECT1"><a name="INIT" id="INIT">4. +Initialization</a></h2> +<p>We now know that to initialize curses system the function +initscr() has to be called. There are functions which can be called +after this initialization to customize our curses session. We may +ask the curses system to set the terminal in raw mode or initialize +color or initialize the mouse etc.. Let's discuss some of the +functions that are normally called immediately after initscr();</p> +<div class="SECT2"> +<hr> +<h3 class="SECT2"><a name="ABOUTINIT" id="ABOUTINIT">4.1. +Initialization functions</a></h3> +</div> +<div class="SECT2"> +<hr> +<h3 class="SECT2"><a name="RAWCBREAK" id="RAWCBREAK">4.2. raw() and +cbreak()</a></h3> +<p>Normally the terminal driver buffers the characters a user types +until a new line or carriage return is encountered. But most +programs require that the characters be available as soon as the +user types them. The above two functions are used to disable line +buffering. The difference between these two functions is in the way +control characters like suspend (CTRL-Z), interrupt and quit +(CTRL-C) are passed to the program. In the raw() mode these +characters are directly passed to the program without generating a +signal. In the <var class="LITERAL">cbreak()</var> mode these +control characters are interpreted as any other character by the +terminal driver. I personally prefer to use raw() as I can exercise +greater control over what the user does.</p> +</div> +<div class="SECT2"> +<hr> +<h3 class="SECT2"><a name="ECHONOECHO" id="ECHONOECHO">4.3. echo() +and noecho()</a></h3> +<p>These functions control the echoing of characters typed by the +user to the terminal. <var class="LITERAL">noecho()</var> switches +off echoing. The reason you might want to do this is to gain more +control over echoing or to suppress unnecessary echoing while +taking input from the user through the getch() etc. functions. Most +of the interactive programs call <var class= +"LITERAL">noecho()</var> at initialization and do the echoing of +characters in a controlled manner. It gives the programmer the +flexibility of echoing characters at any place in the window +without updating current (y,x) co-ordinates.</p> +</div> +<div class="SECT2"> +<hr> +<h3 class="SECT2"><a name="KEYPAD" id="KEYPAD">4.4. +keypad()</a></h3> +<p>This is my favorite initialization function. It enables the +reading of function keys like F1, F2, arrow keys etc. Almost every +interactive program enables this, as arrow keys are a major part of +any User Interface. Do <var class="LITERAL">keypad(stdscr, +TRUE)</var> to enable this feature for the regular screen (stdscr). +You will learn more about key management in later sections of this +document.</p> +</div> +<div class="SECT2"> +<hr> +<h3 class="SECT2"><a name="HALFDELAY" id="HALFDELAY">4.5. +halfdelay()</a></h3> +<p>This function, though not used very often, is a useful one at +times. halfdelay()is called to enable the half-delay mode, which is +similar to the cbreak() mode in that characters typed are +immediately available to program. However, it waits for 'X' tenths +of a second for input and then returns ERR, if no input is +available. 'X' is the timeout value passed to the function +halfdelay(). This function is useful when you want to ask the user +for input, and if he doesn't respond with in certain time, we can +do some thing else. One possible example is a timeout at the +password prompt.</p> +</div> +<div class="SECT2"> +<hr> +<h3 class="SECT2"><a name="MISCINIT" id="MISCINIT">4.6. +Miscellaneous Initialization functions</a></h3> +<p>There are few more functions which are called at initialization +to customize curses behavior. They are not used as extensively as +those mentioned above. Some of them are explained where +appropriate.</p> +</div> +<div class="SECT2"> +<hr> +<h3 class="SECT2"><a name="INITEX" id="INITEX">4.7. An +Example</a></h3> +<p>Let's write a program which will clarify the usage of these +functions.</p> +<div class="EXAMPLE"><a name="BINFU" id="BINFU"></a> +<p><b>Example 2. Initialization Function Usage example</b></p> +<table border="0" bgcolor="#E0E0E0" width="100%"> +<tr> +<td> +<pre class="PROGRAMLISTING"> +<font color="#000000"><span class= +"INLINEMEDIAOBJECT">#include <ncurses.h> + +int main() +{ int ch; + + initscr(); /* Start curses mode */ + raw(); /* Line buffering disabled */ + keypad(stdscr, TRUE); /* We get F1, F2 etc.. */ + noecho(); /* Don't echo() while we do getch */ + + printw("Type any character to see it in bold\n"); + ch = getch(); /* If raw() hadn't been called + * we have to press enter before it + * gets to the program */ + if(ch == KEY_F(1)) /* Without keypad enabled this will */ + printw("F1 Key pressed");/* not get to us either */ + /* Without noecho() some ugly escape + * charachters might have been printed + * on screen */ + else + { printw("The pressed key is "); + attron(A_BOLD); + printw("%c", ch); + attroff(A_BOLD); + } + refresh(); /* Print it on to the real screen */ + getch(); /* Wait for user input */ + endwin(); /* End curses mode */ + + return 0; +}</span></font> +</pre></td> +</tr> +</table> +</div> +<p>This program is self-explanatory. But I used functions which +aren't explained yet. The function <var class= +"LITERAL">getch()</var> is used to get a character from user. It is +equivalent to normal <var class="LITERAL">getchar()</var> except +that we can disable the line buffering to avoid <enter> after +input. Look for more about <var class="LITERAL">getch()</var>and +reading keys in the <a href="#KEYS">key management section</a> . +The functions attron and attroff are used to switch some attributes +on and off respectively. In the example I used them to print the +character in bold. These functions are explained in detail +later.</p> +</div> +</div> +<div class="SECT1"> +<hr> +<h2 class="SECT1"><a name="AWORDWINDOWS" id="AWORDWINDOWS">5. A +Word about Windows</a></h2> +<p>Before we plunge into the myriad ncurses functions, let me clear +few things about windows. Windows are explained in detail in +following <a href="#WINDOWS">sections</a></p> +<p>A Window is an imaginary screen defined by curses system. A +window does not mean a bordered window which you usually see on +Win9X platforms. When curses is initialized, it creates a default +window named <var class="LITERAL">stdscr</var> which represents +your 80x25 (or the size of window in which you are running) screen. +If you are doing simple tasks like printing few strings, reading +input etc., you can safely use this single window for all of your +purposes. You can also create windows and call functions which +explicitly work on the specified window.</p> +<p>For example, if you call</p> +<table border="0" bgcolor="#E0E0E0" width="100%"> +<tr> +<td> +<pre class="PROGRAMLISTING"> +<font color="#000000"> printw("Hi There !!!"); + refresh();</font> +</pre></td> +</tr> +</table> +<p>It prints the string on stdscr at the present cursor position. +Similarly the call to refresh(), works on stdscr only.</p> +<p>Say you have created <a href="#WINDOWS">windows</a> then you +have to call a function with a 'w' added to the usual function.</p> +<table border="0" bgcolor="#E0E0E0" width="100%"> +<tr> +<td> +<pre class="PROGRAMLISTING"> +<font color="#000000"> wprintw(win, "Hi There !!!"); + wrefresh(win);</font> +</pre></td> +</tr> +</table> +<p>As you will see in the rest of the document, naming of functions +follow the same convention. For each function there usually are +three more functions.</p> +<table border="0" bgcolor="#E0E0E0" width="100%"> +<tr> +<td> +<pre class="PROGRAMLISTING"> +<font color= +"#000000"> printw(string); /* Print on stdscr at present cursor position */ + mvprintw(y, x, string);/* Move to (y, x) then print string */ + wprintw(win, string); /* Print on window win at present cursor position */ + /* in the window */ + mvwprintw(win, y, x, string); /* Move to (y, x) relative to window */ + /* co-ordinates and then print */</font> +</pre></td> +</tr> +</table> +<p>Usually the w-less functions are macros which expand to +corresponding w-function with stdscr as the window parameter.</p> +</div> +<div class="SECT1"> +<hr> +<h2 class="SECT1"><a name="PRINTW" id="PRINTW">6. Output +functions</a></h2> +<p>I guess you can't wait any more to see some action. Back to our +odyssey of curses functions. Now that curses is initialized, let's +interact with world.</p> +<p>There are three classes of functions which you can use to do +output on screen.</p> +<ol type="1"> +<li> +<p>addch() class: Print single character with attributes</p> +</li> +<li> +<p>printw() class: Print formatted output similar to printf()</p> +</li> +<li> +<p>addstr() class: Print strings</p> +</li> +</ol> +<p>These functions can be used interchangeably and it's a matter of +style as to which class is used. Let's see each one in detail.</p> +<div class="SECT2"> +<hr> +<h3 class="SECT2"><a name="ADDCHCLASS" id="ADDCHCLASS">6.1. addch() +class of functions</a></h3> +<p>These functions put a single character into the current cursor +location and advance the position of the cursor. You can give the +character to be printed but they usually are used to print a +character with some attributes. Attributes are explained in detail +in later <a href="#ATTRIB">sections</a> of the document. If a +character is associated with an attribute(bold, reverse video +etc.), when curses prints the character, it is printed in that +attribute.</p> +<p>In order to combine a character with some attributes, you have +two options:</p> +<ul> +<li> +<p>By OR'ing a single character with the desired attribute macros. +These attribute macros could be found in the header file +<var class="LITERAL">ncurses.h</var>. For example, you want to +print a character ch(of type char) bold and underlined, you would +call addch() as below.</p> +<table border="0" bgcolor="#E0E0E0" width="90%"> +<tr> +<td> +<pre class="PROGRAMLISTING"> +<font color="#000000"> addch(ch | A_BOLD | A_UNDERLINE);</font> +</pre></td> +</tr> +</table> +</li> +<li> +<p>By using functions like <var class= +"LITERAL">attrset(),attron(),attroff()</var>. These functions are +explained in the <a href="#ATTRIB">Attributes</a> section. Briefly, +they manipulate the current attributes of the given window. Once +set, the character printed in the window are associated with the +attributes until it is turned off.</p> +</li> +</ul> +<p>Additionally, <var class="LITERAL">curses</var> provides some +special characters for character-based graphics. You can draw +tables, horizontal or vertical lines, etc. You can find all +avaliable characters in the header file <var class= +"LITERAL">ncurses.h</var>. Try looking for macros beginning with +<var class="LITERAL">ACS_</var> in this file.</p> +</div> +<div class="SECT2"> +<hr> +<h3 class="SECT2"><a name="AEN298" id="AEN298">6.2. mvaddch(), +waddch() and mvwaddch()</a></h3> +<p><var class="LITERAL">mvaddch()</var> is used to move the cursor +to a given point, and then print. Thus, the calls:</p> +<table border="0" bgcolor="#E0E0E0" width="100%"> +<tr> +<td> +<pre class="PROGRAMLISTING"> +<font color= +"#000000"> move(row,col); /* moves the cursor to row<em>th</em> row and col<em>th</em> column */ + addch(ch);</font> +</pre></td> +</tr> +</table> +can be replaced by +<table border="0" bgcolor="#E0E0E0" width="100%"> +<tr> +<td> +<pre class="PROGRAMLISTING"> +<font color="#000000"> mvaddch(row,col,ch);</font> +</pre></td> +</tr> +</table> +<p><var class="LITERAL">waddch()</var> is similar to <var class= +"LITERAL">addch()</var>, except that it adds a character into the +given window. (Note that <var class="LITERAL">addch()</var> adds a +character into the window <var class="LITERAL">stdscr</var>.)</p> +<p>In a similar fashion <var class="LITERAL">mvwaddch()</var> +function is used to add a character into the given window at the +given coordinates.</p> +<p>Now, we are familiar with the basic output function <var class= +"LITERAL">addch()</var>. But, if we want to print a string, it +would be very annoying to print it character by character. +Fortunately, <var class="LITERAL">ncurses</var> provides +<var class="LITERAL">printf</var><em>-like</em> or <var class= +"LITERAL">puts</var><em>-like</em> functions.</p> +</div> +<div class="SECT2"> +<hr> +<h3 class="SECT2"><a name="PRINTWCLASS" id="PRINTWCLASS">6.3. +printw() class of functions</a></h3> +<p>These functions are similar to <var class= +"LITERAL">printf()</var> with the added capability of printing at +any position on the screen.</p> +<div class="SECT3"> +<hr> +<h4 class="SECT3"><a name="PRINTWMVPRINTW" id= +"PRINTWMVPRINTW">6.3.1. printw() and mvprintw</a></h4> +<p>These two functions work much like <var class= +"LITERAL">printf()</var>. <var class="LITERAL">mvprintw()</var> can +be used to move the cursor to a position and then print. If you +want to move the cursor first and then print using <var class= +"LITERAL">printw()</var> function, use <var class= +"LITERAL">move()</var> first and then use <var class= +"LITERAL">printw()</var> though I see no point why one should avoid +using <var class="LITERAL">mvprintw()</var>, you have the +flexibility to manipulate.</p> +</div> +<div class="SECT3"> +<hr> +<h4 class="SECT3"><a name="WPRINTWMVWPRINTW" id= +"WPRINTWMVWPRINTW">6.3.2. wprintw() and mvwprintw</a></h4> +<p>These two functions are similar to above two except that they +print in the corresponding window given as argument.</p> +</div> +<div class="SECT3"> +<hr> +<h4 class="SECT3"><a name="VWPRINTW" id="VWPRINTW">6.3.3. +vwprintw()</a></h4> +<p>This function is similar to <var class= +"LITERAL">vprintf()</var>. This can be used when variable number of +arguments are to be printed.</p> +</div> +<div class="SECT3"> +<hr> +<h4 class="SECT3"><a name="SIMPLEPRINTWEX" id= +"SIMPLEPRINTWEX">6.3.4. A Simple printw example</a></h4> +<div class="EXAMPLE"><a name="BPREX" id="BPREX"></a> +<p><b>Example 3. A Simple printw example</b></p> +<table border="0" bgcolor="#E0E0E0" width="100%"> +<tr> +<td> +<pre class="PROGRAMLISTING"> +<font color="#000000"><span class= +"INLINEMEDIAOBJECT">#include <ncurses.h> /* ncurses.h includes stdio.h */ +#include <string.h> + +int main() +{ + char mesg[]="Just a string"; /* message to be appeared on the screen */ + int row,col; /* to store the number of rows and * + * the number of colums of the screen */ + initscr(); /* start the curses mode */ + getmaxyx(stdscr,row,col); /* get the number of rows and columns */ + mvprintw(row/2,(col-strlen(mesg))/2,"%s",mesg); + /* print the message at the center of the screen */ + mvprintw(row-2,0,"This screen has %d rows and %d columns\n",row,col); + printw("Try resizing your window(if possible) and then run this program again"); + refresh(); + getch(); + endwin(); + + return 0; +}</span></font> +</pre></td> +</tr> +</table> +</div> +<p>Above program demonstrates how easy it is to use <var class= +"LITERAL">printw</var>. You just feed the coordinates and the +message to be appeared on the screen, then it does what you +want.</p> +<p>The above program introduces us to a new function <var class= +"LITERAL">getmaxyx()</var>, a macro defined in <var class= +"LITERAL">ncurses.h</var>. It gives the number of columns and the +number of rows in a given window. <var class= +"LITERAL">getmaxyx()</var> does this by updating the variables +given to it. Since <var class="LITERAL">getmaxyx()</var> is not a +function we don't pass pointers to it, we just give two integer +variables.</p> +</div> +</div> +<div class="SECT2"> +<hr> +<h3 class="SECT2"><a name="ADDSTRCLASS" id="ADDSTRCLASS">6.4. +addstr() class of functions</a></h3> +<p><var class="LITERAL">addstr()</var> is used to put a character +string into a given window. This function is similar to calling +<var class="LITERAL">addch()</var> once for each character in a +given string. This is true for all output functions. There are +other functions from this family such as <var class= +"LITERAL">mvaddstr(),mvwaddstr()</var> and <var class= +"LITERAL">waddstr()</var>, which obey the naming convention of +curses.(e.g. mvaddstr() is similar to the respective calls move() +and then addstr().) Another function of this family is addnstr(), +which takes an integer parameter(say n) additionally. This function +puts at most n characters into the screen. If n is negative, then +the entire string will be added.</p> +</div> +<div class="SECT2"> +<hr> +<h3 class="SECT2"><a name="ACAUTION" id="ACAUTION">6.5. A word of +caution</a></h3> +<p>All these functions take y co-ordinate first and then x in their +arguments. A common mistake by beginners is to pass x,y in that +order. If you are doing too many manipulations of (y,x) +co-ordinates, think of dividing the screen into windows and +manipulate each one separately. Windows are explained in the +<a href="#WINDOWS">windows</a> section.</p> +</div> +</div> +<div class="SECT1"> +<hr> +<h2 class="SECT1"><a name="SCANW" id="SCANW">7. Input +functions</a></h2> +<p>Well, printing without taking input, is boring. Let's see +functions which allow us to get input from user. These functions +also can be divided into three categories.</p> +<ol type="1"> +<li> +<p>getch() class: Get a character</p> +</li> +<li> +<p>scanw() class: Get formatted input</p> +</li> +<li> +<p>getstr() class: Get strings</p> +</li> +</ol> +<div class="SECT2"> +<hr> +<h3 class="SECT2"><a name="GETCHCLASS" id="GETCHCLASS">7.1. getch() +class of functions</a></h3> +<p>These functions read a single character from the terminal. But +there are several subtle facts to consider. For example if you +don't use the function cbreak(), curses will not read your input +characters contiguously but will begin read them only after a new +line or an EOF is encountered. In order to avoid this, the cbreak() +function must used so that characters are immediately available to +your program. Another widely used function is noecho(). As the name +suggests, when this function is set (used), the characters that are +keyed in by the user will not show up on the screen. The two +functions cbreak() and noecho() are typical examples of key +management. Functions of this genre are explained in the <a href= +"#KEYS">key management section</a> .</p> +</div> +<div class="SECT2"> +<hr> +<h3 class="SECT2"><a name="SCANWCLASS" id="SCANWCLASS">7.2. scanw() +class of functions</a></h3> +<p>These functions are similar to <var class= +"LITERAL">scanf()</var> with the added capability of getting the +input from any location on the screen.</p> +<div class="SECT3"> +<hr> +<h4 class="SECT3"><a name="SCANWMVSCANW" id="SCANWMVSCANW">7.2.1. +scanw() and mvscanw</a></h4> +<p>The usage of these functions is similar to that of <var class= +"LITERAL">sscanf()</var>, where the line to be scanned is provided +by <var class="LITERAL">wgetstr()</var> function. That is, these +functions call to <var class="LITERAL">wgetstr()</var> +function(explained below) and uses the resulting line for a +scan.</p> +</div> +<div class="SECT3"> +<hr> +<h4 class="SECT3"><a name="WSCANWMVWSCANW" id= +"WSCANWMVWSCANW">7.2.2. wscanw() and mvwscanw()</a></h4> +<p>These are similar to above two functions except that they read +from a window, which is supplied as one of the arguments to these +functions.</p> +</div> +<div class="SECT3"> +<hr> +<h4 class="SECT3"><a name="VWSCANW" id="VWSCANW">7.2.3. +vwscanw()</a></h4> +<p>This function is similar to <var class="LITERAL">vscanf()</var>. +This can be used when a variable number of arguments are to be +scanned.</p> +</div> +</div> +<div class="SECT2"> +<hr> +<h3 class="SECT2"><a name="GETSTRCLASS" id="GETSTRCLASS">7.3. +getstr() class of functions</a></h3> +<p>These functions are used to get strings from the terminal. In +essence, this function performs the same task as would be achieved +by a series of calls to <var class="LITERAL">getch()</var> until a +newline, carriage return, or end-of-file is received. The resulting +string of characters are pointed to by <var class= +"LITERAL">str</var>, which is a character pointer provided by the +user.</p> +</div> +<div class="SECT2"> +<hr> +<h3 class="SECT2"><a name="GETSTREX" id="GETSTREX">7.4. Some +examples</a></h3> +<div class="EXAMPLE"><a name="BSCEX" id="BSCEX"></a> +<p><b>Example 4. A Simple scanw example</b></p> +<table border="0" bgcolor="#E0E0E0" width="100%"> +<tr> +<td> +<pre class="PROGRAMLISTING"> +<font color="#000000"><span class= +"INLINEMEDIAOBJECT">#include <ncurses.h> /* ncurses.h includes stdio.h */ +#include <string.h> + +int main() +{ + char mesg[]="Enter a string: "; /* message to be appeared on the screen */ + char str[80]; + int row,col; /* to store the number of rows and * + * the number of colums of the screen */ + initscr(); /* start the curses mode */ + getmaxyx(stdscr,row,col); /* get the number of rows and columns */ + mvprintw(row/2,(col-strlen(mesg))/2,"%s",mesg); + /* print the message at the center of the screen */ + getstr(str); + mvprintw(LINES - 2, 0, "You Entered: %s", str); + getch(); + endwin(); + + return 0; +}</span></font> +</pre></td> +</tr> +</table> +</div> +</div> +</div> +<div class="SECT1"> +<hr> +<h2 class="SECT1"><a name="ATTRIB" id="ATTRIB">8. +Attributes</a></h2> +<p>We have seen an example of how attributes can be used to print +characters with some special effects. Attributes, when set +prudently, can present information in an easy, understandable +manner. The following program takes a C file as input and prints +the file with comments in bold. Scan through the code.</p> +<div class="EXAMPLE"><a name="BSIAT" id="BSIAT"></a> +<p><b>Example 5. A Simple Attributes example</b></p> +<table border="0" bgcolor="#E0E0E0" width="100%"> +<tr> +<td> +<pre class="PROGRAMLISTING"> +<font color="#000000"><span class= +"INLINEMEDIAOBJECT">/* pager functionality by Joseph Spainhour" <spainhou@bellsouth.net> */ +#include <ncurses.h> +#include <stdlib.h> + +int main(int argc, char *argv[]) +{ + int ch, prev, row, col; + prev = EOF; + FILE *fp; + int y, x; + + if(argc != 2) + { + printf("Usage: %s <a c file name>\n", argv[0]); + exit(1); + } + fp = fopen(argv[1], "r"); + if(fp == NULL) + { + perror("Cannot open input file"); + exit(1); + } + initscr(); /* Start curses mode */ + getmaxyx(stdscr, row, col); /* find the boundaries of the screeen */ + while((ch = fgetc(fp)) != EOF) /* read the file till we reach the end */ + { + getyx(stdscr, y, x); /* get the current curser position */ + if(y == (row - 1)) /* are we are at the end of the screen */ + { + printw("<-Press Any Key->"); /* tell the user to press a key */ + getch(); + clear(); /* clear the screen */ + move(0, 0); /* start at the beginning of the screen */ + } + if(prev == '/' && ch == '*') /* If it is / and * then only + * switch bold on */ + { + attron(A_BOLD); /* cut bold on */ + getyx(stdscr, y, x); /* get the current curser position */ + move(y, x - 1); /* back up one space */ + printw("%c%c", '/', ch); /* The actual printing is done here */ + } + else + printw("%c", ch); + refresh(); + if(prev == '*' && ch == '/') + attroff(A_BOLD); /* Switch it off once we got * + * and then / */ + prev = ch; + } + endwin(); /* End curses mode */ + fclose(fp); + return 0; +}</span></font> +</pre></td> +</tr> +</table> +</div> +<p>Don't worry about all those initialization and other crap. +Concentrate on the while loop. It reads each character in the file +and searches for the pattern /*. Once it spots the pattern, it +switches the BOLD attribute on with <var class= +"LITERAL">attron()</var> . When we get the pattern */ it is +switched off by <var class="LITERAL">attroff()</var> .</p> +<p>The above program also introduces us to two useful functions +<var class="LITERAL">getyx()</var> and <var class= +"LITERAL">move()</var>. The first function gets the co-ordinates of +the present cursor into the variables y, x. Since getyx() is a +macro we don't have to pass pointers to variables. The function +<var class="LITERAL">move()</var> moves the cursor to the +co-ordinates given to it.</p> +<p>The above program is really a simple one which doesn't do much. +On these lines one could write a more useful program which reads a +C file, parses it and prints it in different colors. One could even +extend it to other languages as well.</p> +<div class="SECT2"> +<hr> +<h3 class="SECT2"><a name="ATTRIBDETAILS" id="ATTRIBDETAILS">8.1. +The details</a></h3> +<p>Let's get into more details of attributes. The functions +<var class="LITERAL">attron(), attroff(), attrset()</var> , and +their sister functions <var class="LITERAL">attr_get()</var> etc.. +can be used to switch attributes on/off , get attributes and +produce a colorful display.</p> +<p>The functions attron and attroff take a bit-mask of attributes +and switch them on or off, respectively. The following video +attributes, which are defined in <curses.h> can be passed to +these functions.</p> +<table border="0" bgcolor="#E0E0E0" width="100%"> +<tr> +<td> +<pre class="PROGRAMLISTING"> +<font color="#000000"> + A_NORMAL Normal display (no highlight) + A_STANDOUT Best highlighting mode of the terminal. + A_UNDERLINE Underlining + A_REVERSE Reverse video + A_BLINK Blinking + A_DIM Half bright + A_BOLD Extra bright or bold + A_PROTECT Protected mode + A_INVIS Invisible or blank mode + A_ALTCHARSET Alternate character set + A_CHARTEXT Bit-mask to extract a character + COLOR_PAIR(n) Color-pair number n + </font> +</pre></td> +</tr> +</table> +<p>The last one is the most colorful one :-) Colors are explained +in the <a href="#color" target="_top">next sections</a>.</p> +<p>We can OR(|) any number of above attributes to get a combined +effect. If you wanted reverse video with blinking characters you +can use</p> +<table border="0" bgcolor="#E0E0E0" width="100%"> +<tr> +<td> +<pre class="PROGRAMLISTING"> +<font color="#000000"> attron(A_REVERSE | A_BLINK);</font> +</pre></td> +</tr> +</table> +</div> +<div class="SECT2"> +<hr> +<h3 class="SECT2"><a name="ATTRONVSATTRSET" id= +"ATTRONVSATTRSET">8.2. attron() vs attrset()</a></h3> +<p>Then what is the difference between attron() and attrset()? +attrset sets the attributes of window whereas attron just switches +on the attribute given to it. So attrset() fully overrides whatever +attributes the window previously had and sets it to the new +attribute(s). Similarly attroff() just switches off the +attribute(s) given to it as an argument. This gives us the +flexibility of managing attributes easily.But if you use them +carelessly you may loose track of what attributes the window has +and garble the display. This is especially true while managing +menus with colors and highlighting. So decide on a consistent +policy and stick to it. You can always use <var class= +"LITERAL">standend()</var> which is equivalent to <var class= +"LITERAL">attrset(A_NORMAL)</var> which turns off all attributes +and brings you to normal mode.</p> +</div> +<div class="SECT2"> +<hr> +<h3 class="SECT2"><a name="ATTR_GET" id="ATTR_GET">8.3. +attr_get()</a></h3> +<p>The function attr_get() gets the current attributes and color +pair of the window. Though we might not use this as often as the +above functions, this is useful in scanning areas of screen. Say we +wanted to do some complex update on screen and we are not sure what +attribute each character is associated with. Then this function can +be used with either attrset or attron to produce the desired +effect.</p> +</div> +<div class="SECT2"> +<hr> +<h3 class="SECT2"><a name="ATTR_FUNCS" id="ATTR_FUNCS">8.4. attr_ +functions</a></h3> +<p>There are series of functions like attr_set(), attr_on etc.. +These are similar to above functions except that they take +parameters of type <var class="LITERAL">attr_t</var>.</p> +</div> +<div class="SECT2"> +<hr> +<h3 class="SECT2"><a name="WATTRFUNCS" id="WATTRFUNCS">8.5. wattr +functions</a></h3> +<p>For each of the above functions we have a corresponding function +with 'w' which operates on a particular window. The above functions +operate on stdscr.</p> +</div> +<div class="SECT2"> +<hr> +<h3 class="SECT2"><a name="CHGAT" id="CHGAT">8.6. chgat() +functions</a></h3> +<p>The function chgat() is listed in the end of the man page +curs_attr. It actually is a useful one. This function can be used +to set attributes for a group of characters without moving. I mean +it !!! without moving the cursor :-) It changes the attributes of a +given number of characters starting at the current cursor +location.</p> +<p>We can give -1 as the character count to update till end of +line. If you want to change attributes of characters from current +position to end of line, just use this.</p> +<table border="0" bgcolor="#E0E0E0" width="100%"> +<tr> +<td> +<pre class="PROGRAMLISTING"> +<font color="#000000"> chgat(-1, A_REVERSE, 0, NULL);</font> +</pre></td> +</tr> +</table> +<p>This function is useful when changing attributes for characters +that are already on the screen. Move to the character from which +you want to change and change the attribute.</p> +<p>Other functions wchgat(), mvchgat(), wchgat() behave similarly +except that the w functions operate on the particular window. The +mv functions first move the cursor then perform the work given to +them. Actually chgat is a macro which is replaced by a wchgat() +with stdscr as the window. Most of the "w-less" functions are +macros.</p> +<div class="EXAMPLE"><a name="BWICH" id="BWICH"></a> +<p><b>Example 6. Chgat() Usage example</b></p> +<table border="0" bgcolor="#E0E0E0" width="100%"> +<tr> +<td> +<pre class="PROGRAMLISTING"> +<font color="#000000"><span class= +"INLINEMEDIAOBJECT">#include <ncurses.h> + +int main(int argc, char *argv[]) +{ initscr(); /* Start curses mode */ + start_color(); /* Start color functionality */ + + init_pair(1, COLOR_CYAN, COLOR_BLACK); + printw("A Big string which i didn't care to type fully "); + mvchgat(0, 0, -1, A_BLINK, 1, NULL); + /* + * First two parameters specify the position at which to start + * Third parameter number of characters to update. -1 means till + * end of line + * Forth parameter is the normal attribute you wanted to give + * to the charcter + * Fifth is the color index. It is the index given during init_pair() + * use 0 if you didn't want color + * Sixth one is always NULL + */ + refresh(); + getch(); + endwin(); /* End curses mode */ + return 0; +}</span></font> +</pre></td> +</tr> +</table> +</div> +<p>This example also introduces us to the color world of curses. +Colors will be explained in detail later. Use 0 for no color.</p> +</div> +</div> +<div class="SECT1"> +<hr> +<h2 class="SECT1"><a name="WINDOWS" id="WINDOWS">9. +Windows</a></h2> +<p>Windows form the most important concept in curses. You have seen +the standard window stdscr above where all the functions implicitly +operated on this window. Now to make design even a simplest GUI, +you need to resort to windows. The main reason you may want to use +windows is to manipulate parts of the screen separately, for better +efficiency, by updating only the windows that need to be changed +and for a better design. I would say the last reason is the most +important in going for windows. You should always strive for a +better and easy-to-manage design in your programs. If you are +writing big, complex GUIs this is of pivotal importance before you +start doing anything.</p> +<div class="SECT2"> +<hr> +<h3 class="SECT2"><a name="WINDOWBASICS" id="WINDOWBASICS">9.1. The +basics</a></h3> +<p>A Window can be created by calling the function <var class= +"LITERAL">newwin()</var>. It doesn't create any thing on the screen +actually. It allocates memory for a structure to manipulate the +window and updates the structure with data regarding the window +like it's size, beginy, beginx etc.. Hence in curses, a window is +just an abstraction of an imaginary window, which can be +manipulated independent of other parts of screen. The function +newwin() returns a pointer to structure WINDOW, which can be passed +to window related functions like wprintw() etc.. Finally the window +can be destroyed with delwin(). It will deallocate the memory +associated with the window structure.</p> +</div> +<div class="SECT2"> +<hr> +<h3 class="SECT2"><a name="LETBEWINDOW" id="LETBEWINDOW">9.2. Let +there be a Window !!!</a></h3> +<p>What fun is it, if a window is created and we can't see it. So +the fun part begins by displaying the window. The function +<var class="LITERAL">box()</var> can be used to draw a border +around the window. Let's explore these functions in more detail in +this example.</p> +<div class="EXAMPLE"><a name="BWIBO" id="BWIBO"></a> +<p><b>Example 7. Window Border example</b></p> +<table border="0" bgcolor="#E0E0E0" width="100%"> +<tr> +<td> +<pre class="PROGRAMLISTING"> +<font color="#000000"><span class= +"INLINEMEDIAOBJECT">#include <ncurses.h> + + +WINDOW *create_newwin(int height, int width, int starty, int startx); +void destroy_win(WINDOW *local_win); + +int main(int argc, char *argv[]) +{ WINDOW *my_win; + int startx, starty, width, height; + int ch; + + initscr(); /* Start curses mode */ + cbreak(); /* Line buffering disabled, Pass on + * everty thing to me */ + keypad(stdscr, TRUE); /* I need that nifty F1 */ + + height = 3; + width = 10; + starty = (LINES - height) / 2; /* Calculating for a center placement */ + startx = (COLS - width) / 2; /* of the window */ + printw("Press F1 to exit"); + refresh(); + my_win = create_newwin(height, width, starty, startx); + + while((ch = getch()) != KEY_F(1)) + { switch(ch) + { case KEY_LEFT: + destroy_win(my_win); + my_win = create_newwin(height, width, starty,--startx); + break; + case KEY_RIGHT: + destroy_win(my_win); + my_win = create_newwin(height, width, starty,++startx); + break; + case KEY_UP: + destroy_win(my_win); + my_win = create_newwin(height, width, --starty,startx); + break; + case KEY_DOWN: + destroy_win(my_win); + my_win = create_newwin(height, width, ++starty,startx); + break; + } + } + + endwin(); /* End curses mode */ + return 0; +} + +WINDOW *create_newwin(int height, int width, int starty, int startx) +{ WINDOW *local_win; + + local_win = newwin(height, width, starty, startx); + box(local_win, 0 , 0); /* 0, 0 gives default characters + * for the vertical and horizontal + * lines */ + wrefresh(local_win); /* Show that box */ + + return local_win; +} + +void destroy_win(WINDOW *local_win) +{ + /* box(local_win, ' ', ' '); : This won't produce the desired + * result of erasing the window. It will leave it's four corners + * and so an ugly remnant of window. + */ + wborder(local_win, ' ', ' ', ' ',' ',' ',' ',' ',' '); + /* The parameters taken are + * 1. win: the window on which to operate + * 2. ls: character to be used for the left side of the window + * 3. rs: character to be used for the right side of the window + * 4. ts: character to be used for the top side of the window + * 5. bs: character to be used for the bottom side of the window + * 6. tl: character to be used for the top left corner of the window + * 7. tr: character to be used for the top right corner of the window + * 8. bl: character to be used for the bottom left corner of the window + * 9. br: character to be used for the bottom right corner of the window + */ + wrefresh(local_win); + delwin(local_win); +}</span></font> +</pre></td> +</tr> +</table> +</div> +</div> +<div class="SECT2"> +<hr> +<h3 class="SECT2"><a name="BORDEREXEXPL" id="BORDEREXEXPL">9.3. +Explanation</a></h3> +<p>Don't scream. I know it's a big example. But I have to explain +some important things here :-). This program creates a rectangular +window that can be moved with left, right, up, down arrow keys. It +repeatedly creates and destroys windows as user press a key. Don't +go beyond the screen limits. Checking for those limits is left as +an exercise for the reader. Let's dissect it by line by line.</p> +<p>The <var class="LITERAL">create_newwin()</var> function creates +a window with <var class="LITERAL">newwin()</var> and displays a +border around it with box. The function <var class= +"LITERAL">destroy_win()</var> first erases the window from screen +by painting a border with ' ' character and then calling +<var class="LITERAL">delwin()</var> to deallocate memory related to +it. Depending on the key the user presses, starty or startx is +changed and a new window is created.</p> +<p>In the destroy_win, as you can see, I used wborder instead of +box. The reason is written in the comments (You missed it. I know. +Read the code :-)). wborder draws a border around the window with +the characters given to it as the 4 corner points and the 4 lines. +To put it clearly, if you have called wborder as below:</p> +<table border="0" bgcolor="#E0E0E0" width="100%"> +<tr> +<td> +<pre class="PROGRAMLISTING"> +<font color= +"#000000"> wborder(win, '|', '|', '-', '-', '+', '+', '+', '+');</font> +</pre></td> +</tr> +</table> +<p>it produces some thing like</p> +<table border="0" bgcolor="#E0E0E0" width="100%"> +<tr> +<td> +<pre class="PROGRAMLISTING"> +<font color="#000000"> +------------+ + | | + | | + | | + | | + | | + | | + +------------+</font> +</pre></td> +</tr> +</table> +</div> +<div class="SECT2"> +<hr> +<h3 class="SECT2"><a name="OTHERSTUFF" id="OTHERSTUFF">9.4. The +other stuff in the example</a></h3> +<p>You can also see in the above examples, that I have used the +variables COLS, LINES which are initialized to the screen sizes +after initscr(). They can be useful in finding screen dimensions +and finding the center co-ordinate of the screen as above. The +function <var class="LITERAL">getch()</var> as usual gets the key +from keyboard and according to the key it does the corresponding +work. This type of switch- case is very common in any GUI based +programs.</p> +</div> +<div class="SECT2"> +<hr> +<h3 class="SECT2"><a name="OTHERBORDERFUNCS" id= +"OTHERBORDERFUNCS">9.5. Other Border functions</a></h3> +<p>Above program is grossly inefficient in that with each press of +a key, a window is destroyed and another is created. So let's write +a more efficient program which uses other border related +functions.</p> +<p>The following program uses <var class="LITERAL">mvhline()</var> +and <var class="LITERAL">mvvline()</var> to achieve similar effect. +These two functions are simple. They create a horizontal or +vertical line of the specified length at the specified +position.</p> +<div class="EXAMPLE"><a name="BOTBO" id="BOTBO"></a> +<p><b>Example 8. More border functions</b></p> +<table border="0" bgcolor="#E0E0E0" width="100%"> +<tr> +<td> +<pre class="PROGRAMLISTING"> +<font color="#000000"><span class= +"INLINEMEDIAOBJECT">#include <ncurses.h> + +typedef struct _win_border_struct { + chtype ls, rs, ts, bs, + tl, tr, bl, br; +}WIN_BORDER; + +typedef struct _WIN_struct { + + int startx, starty; + int height, width; + WIN_BORDER border; +}WIN; + +void init_win_params(WIN *p_win); +void print_win_params(WIN *p_win); +void create_box(WIN *win, bool flag); + +int main(int argc, char *argv[]) +{ WIN win; + int ch; + + initscr(); /* Start curses mode */ + start_color(); /* Start the color functionality */ + cbreak(); /* Line buffering disabled, Pass on + * everty thing to me */ + keypad(stdscr, TRUE); /* I need that nifty F1 */ + noecho(); + init_pair(1, COLOR_CYAN, COLOR_BLACK); + + /* Initialize the window parameters */ + init_win_params(&win); + print_win_params(&win); + + attron(COLOR_PAIR(1)); + printw("Press F1 to exit"); + refresh(); + attroff(COLOR_PAIR(1)); + + create_box(&win, TRUE); + while((ch = getch()) != KEY_F(1)) + { switch(ch) + { case KEY_LEFT: + create_box(&win, FALSE); + --win.startx; + create_box(&win, TRUE); + break; + case KEY_RIGHT: + create_box(&win, FALSE); + ++win.startx; + create_box(&win, TRUE); + break; + case KEY_UP: + create_box(&win, FALSE); + --win.starty; + create_box(&win, TRUE); + break; + case KEY_DOWN: + create_box(&win, FALSE); + ++win.starty; + create_box(&win, TRUE); + break; + } + } + endwin(); /* End curses mode */ + return 0; +} +void init_win_params(WIN *p_win) +{ + p_win->height = 3; + p_win->width = 10; + p_win->starty = (LINES - p_win->height)/2; + p_win->startx = (COLS - p_win->width)/2; + + p_win->border.ls = '|'; + p_win->border.rs = '|'; + p_win->border.ts = '-'; + p_win->border.bs = '-'; + p_win->border.tl = '+'; + p_win->border.tr = '+'; + p_win->border.bl = '+'; + p_win->border.br = '+'; + +} +void print_win_params(WIN *p_win) +{ +#ifdef _DEBUG + mvprintw(25, 0, "%d %d %d %d", p_win->startx, p_win->starty, + p_win->width, p_win->height); + refresh(); +#endif +} +void create_box(WIN *p_win, bool flag) +{ int i, j; + int x, y, w, h; + + x = p_win->startx; + y = p_win->starty; + w = p_win->width; + h = p_win->height; + + if(flag == TRUE) + { mvaddch(y, x, p_win->border.tl); + mvaddch(y, x + w, p_win->border.tr); + mvaddch(y + h, x, p_win->border.bl); + mvaddch(y + h, x + w, p_win->border.br); + mvhline(y, x + 1, p_win->border.ts, w - 1); + mvhline(y + h, x + 1, p_win->border.bs, w - 1); + mvvline(y + 1, x, p_win->border.ls, h - 1); + mvvline(y + 1, x + w, p_win->border.rs, h - 1); + + } + else + for(j = y; j <= y + h; ++j) + for(i = x; i <= x + w; ++i) + mvaddch(j, i, ' '); + + refresh(); + +}</span></font> +</pre></td> +</tr> +</table> +</div> +</div> +</div> +<div class="SECT1"> +<hr> +<h2 class="SECT1"><a name="COLOR" id="COLOR">10. Colors</a></h2> +<div class="SECT2"> +<h3 class="SECT2"><a name="COLORBASICS" id="COLORBASICS">10.1. The +basics</a></h3> +<p>Life seems dull with no colors. Curses has a nice mechanism to +handle colors. Let's get into the thick of the things with a small +program.</p> +<div class="EXAMPLE"><a name="BSICO" id="BSICO"></a> +<p><b>Example 9. A Simple Color example</b></p> +<table border="0" bgcolor="#E0E0E0" width="100%"> +<tr> +<td> +<pre class="PROGRAMLISTING"> +<font color="#000000"><span class= +"INLINEMEDIAOBJECT">#include <ncurses.h> + +void print_in_middle(WINDOW *win, int starty, int startx, int width, char *string); +int main(int argc, char *argv[]) +{ initscr(); /* Start curses mode */ + if(has_colors() == FALSE) + { endwin(); + printf("Your terminal does not support color\n"); + exit(1); + } + start_color(); /* Start color */ + init_pair(1, COLOR_RED, COLOR_BLACK); + + attron(COLOR_PAIR(1)); + print_in_middle(stdscr, LINES / 2, 0, 0, "Viola !!! In color ..."); + attroff(COLOR_PAIR(1)); + getch(); + endwin(); +} +void print_in_middle(WINDOW *win, int starty, int startx, int width, char *string) +{ int length, x, y; + float temp; + + if(win == NULL) + win = stdscr; + getyx(win, y, x); + if(startx != 0) + x = startx; + if(starty != 0) + y = starty; + if(width == 0) + width = 80; + + length = strlen(string); + temp = (width - length)/ 2; + x = startx + (int)temp; + mvwprintw(win, y, x, "%s", string); + refresh(); +} +</span></font> +</pre></td> +</tr> +</table> +</div> +<p>As you can see, to start using color, you should first call the +function <var class="LITERAL">start_color()</var>. After that, you +can use color capabilities of your terminals using various +functions. To find out whether a terminal has color capabilities or +not, you can use <var class="LITERAL">has_colors()</var> function, +which returns FALSE if the terminal does not support color.</p> +<p>Curses initializes all the colors supported by terminal when +start_color() is called. These can be accessed by the define +constants like <var class="LITERAL">COLOR_BLACK</var> etc. Now to +actually start using colors, you have to define pairs. Colors are +always used in pairs. That means you have to use the function +<var class="LITERAL">init_pair()</var> to define the foreground and +background for the pair number you give. After that that pair +number can be used as a normal attribute with <var class= +"LITERAL">COLOR_PAIR()</var>function. This may seem to be +cumbersome at first. But this elegant solution allows us to manage +color pairs very easily. To appreciate it, you have to look into +the the source code of "dialog", a utility for displaying dialog +boxes from shell scripts. The developers have defined foreground +and background combinations for all the colors they might need and +initialized at the beginning. This makes it very easy to set +attributes just by accessing a pair which we already have defined +as a constant.</p> +<p>The following colors are defined in <var class= +"LITERAL">curses.h</var>. You can use these as parameters for +various color functions.</p> +<table border="0" bgcolor="#E0E0E0" width="100%"> +<tr> +<td> +<pre class="PROGRAMLISTING"> +<font color="#000000"> COLOR_BLACK 0 + COLOR_RED 1 + COLOR_GREEN 2 + COLOR_YELLOW 3 + COLOR_BLUE 4 + COLOR_MAGENTA 5 + COLOR_CYAN 6 + COLOR_WHITE 7</font> +</pre></td> +</tr> +</table> +</div> +<div class="SECT2"> +<hr> +<h3 class="SECT2"><a name="CHANGECOLORDEFS" id= +"CHANGECOLORDEFS">10.2. Changing Color Definitions</a></h3> +<p>The function <var class="LITERAL">init_color()</var>can be used +to change the rgb values for the colors defined by curses +initially. Say you wanted to lighten the intensity of red color by +a minuscule. Then you can use this function as</p> +<table border="0" bgcolor="#E0E0E0" width="100%"> +<tr> +<td> +<pre class="PROGRAMLISTING"> +<font color="#000000"> init_color(COLOR_RED, 700, 0, 0); + /* param 1 : color name + * param 2, 3, 4 : rgb content min = 0, max = 1000 */</font> +</pre></td> +</tr> +</table> +<p>If your terminal cannot change the color definitions, the +function returns ERR. The function <var class= +"LITERAL">can_change_color()</var> can be used to find out whether +the terminal has the capability of changing color content or not. +The rgb content is scaled from 0 to 1000. Initially RED color is +defined with content 1000(r), 0(g), 0(b).</p> +</div> +<div class="SECT2"> +<hr> +<h3 class="SECT2"><a name="COLORCONTENT" id="COLORCONTENT">10.3. +Color Content</a></h3> +<p>The functions <var class="LITERAL">color_content()</var> and +<var class="LITERAL">pair_content()</var> can be used to find the +color content and foreground, background combination for the +pair.</p> +</div> +</div> +<div class="SECT1"> +<hr> +<h2 class="SECT1"><a name="KEYS" id="KEYS">11. Interfacing with the +key board</a></h2> +<div class="SECT2"> +<h3 class="SECT2"><a name="KEYSBASICS" id="KEYSBASICS">11.1. The +Basics</a></h3> +<p>No GUI is complete without a strong user interface and to +interact with the user, a curses program should be sensitive to key +presses or the mouse actions done by the user. Let's deal with the +keys first.</p> +<p>As you have seen in almost all of the above examples, it's very +easy to get key input from the user. A simple way of getting key +presses is to use <var class="LITERAL">getch()</var> function. The +cbreak mode should be enabled to read keys when you are interested +in reading individual key hits rather than complete lines of text +(which usually end with a carriage return). keypad should be +enabled to get the Functions keys, arrow keys etc. See the +initialization section for details.</p> +<p><var class="LITERAL">getch()</var> returns an integer +corresponding to the key pressed. If it is a normal character, the +integer value will be equivalent to the character. Otherwise it +returns a number which can be matched with the constants defined in +<var class="LITERAL">curses.h</var>. For example if the user +presses F1, the integer returned is 265. This can be checked using +the macro KEY_F() defined in curses.h. This makes reading keys +portable and easy to manage.</p> +<p>For example, if you call getch() like this</p> +<table border="0" bgcolor="#E0E0E0" width="100%"> +<tr> +<td> +<pre class="PROGRAMLISTING"> +<font color="#000000"> int ch; + + ch = getch();</font> +</pre></td> +</tr> +</table> +<p>getch() will wait for the user to press a key, (unless you +specified a timeout) and when user presses a key, the corresponding +integer is returned. Then you can check the value returned with the +constants defined in curses.h to match against the keys you +want.</p> +<p>The following code piece will do that job.</p> +<table border="0" bgcolor="#E0E0E0" width="100%"> +<tr> +<td> +<pre class="PROGRAMLISTING"> +<font color="#000000"> if(ch == KEY_LEFT) + printw("Left arrow is pressed\n");</font> +</pre></td> +</tr> +</table> +<p>Let's write a small program which creates a menu which can be +navigated by up and down arrows.</p> +</div> +<div class="SECT2"> +<hr> +<h3 class="SECT2"><a name="SIMPLEKEYEX" id="SIMPLEKEYEX">11.2. A +Simple Key Usage example</a></h3> +<div class="EXAMPLE"><a name="BSIKE" id="BSIKE"></a> +<p><b>Example 10. A Simple Key Usage example</b></p> +<table border="0" bgcolor="#E0E0E0" width="100%"> +<tr> +<td> +<pre class="PROGRAMLISTING"> +<font color="#000000"><span class= +"INLINEMEDIAOBJECT">#include <stdio.h> +#include <ncurses.h> + +#define WIDTH 30 +#define HEIGHT 10 + +int startx = 0; +int starty = 0; + +char *choices[] = { + "Choice 1", + "Choice 2", + "Choice 3", + "Choice 4", + "Exit", + }; +int n_choices = sizeof(choices) / sizeof(char *); +void print_menu(WINDOW *menu_win, int highlight); + +int main() +{ WINDOW *menu_win; + int highlight = 1; + int choice = 0; + int c; + + initscr(); + clear(); + noecho(); + cbreak(); /* Line buffering disabled. pass on everything */ + startx = (80 - WIDTH) / 2; + starty = (24 - HEIGHT) / 2; + + menu_win = newwin(HEIGHT, WIDTH, starty, startx); + keypad(menu_win, TRUE); + mvprintw(0, 0, "Use arrow keys to go up and down, Press enter to select a choice"); + refresh(); + print_menu(menu_win, highlight); + while(1) + { c = wgetch(menu_win); + switch(c) + { case KEY_UP: + if(highlight == 1) + highlight = n_choices; + else + --highlight; + break; + case KEY_DOWN: + if(highlight == n_choices) + highlight = 1; + else + ++highlight; + break; + case 10: + choice = highlight; + break; + default: + mvprintw(24, 0, "Charcter pressed is = %3d Hopefully it can be printed as '%c'", c, c); + refresh(); + break; + } + print_menu(menu_win, highlight); + if(choice != 0) /* User did a choice come out of the infinite loop */ + break; + } + mvprintw(23, 0, "You chose choice %d with choice string %s\n", choice, choices[choice - 1]); + clrtoeol(); + refresh(); + endwin(); + return 0; +} + + +void print_menu(WINDOW *menu_win, int highlight) +{ + int x, y, i; + + x = 2; + y = 2; + box(menu_win, 0, 0); + for(i = 0; i < n_choices; ++i) + { if(highlight == i + 1) /* High light the present choice */ + { wattron(menu_win, A_REVERSE); + mvwprintw(menu_win, y, x, "%s", choices[i]); + wattroff(menu_win, A_REVERSE); + } + else + mvwprintw(menu_win, y, x, "%s", choices[i]); + ++y; + } + wrefresh(menu_win); +} +</span></font> +</pre></td> +</tr> +</table> +</div> +</div> +</div> +<div class="SECT1"> +<hr> +<h2 class="SECT1"><a name="MOUSE" id="MOUSE">12. Interfacing with +the mouse</a></h2> +<p>Now that you have seen how to get keys, lets do the same thing +from mouse. Usually each UI allows the user to interact with both +keyboard and mouse.</p> +<div class="SECT2"> +<hr> +<h3 class="SECT2"><a name="MOUSEBASICS" id="MOUSEBASICS">12.1. The +Basics</a></h3> +<p>Before you do any thing else, the events you want to receive +have to be enabled with <var class="LITERAL">mousemask()</var>.</p> +<table border="0" bgcolor="#E0E0E0" width="100%"> +<tr> +<td> +<pre class="PROGRAMLISTING"> +<font color= +"#000000"> mousemask( mmask_t newmask, /* The events you want to listen to */ + mmask_t *oldmask) /* The old events mask */</font> +</pre></td> +</tr> +</table> +<p>The first parameter to above function is a bit mask of events +you would like to listen. By default, all the events are turned +off. The bit mask <var class="LITERAL">ALL_MOUSE_EVENTS</var> can +be used to get all the events.</p> +<p>The following are all the event masks:</p> +<table border="0" bgcolor="#E0E0E0" width="100%"> +<tr> +<td> +<pre class="PROGRAMLISTING"> +<font color="#000000"> Name Description + --------------------------------------------------------------------- + BUTTON1_PRESSED mouse button 1 down + BUTTON1_RELEASED mouse button 1 up + BUTTON1_CLICKED mouse button 1 clicked + BUTTON1_DOUBLE_CLICKED mouse button 1 double clicked + BUTTON1_TRIPLE_CLICKED mouse button 1 triple clicked + BUTTON2_PRESSED mouse button 2 down + BUTTON2_RELEASED mouse button 2 up + BUTTON2_CLICKED mouse button 2 clicked + BUTTON2_DOUBLE_CLICKED mouse button 2 double clicked + BUTTON2_TRIPLE_CLICKED mouse button 2 triple clicked + BUTTON3_PRESSED mouse button 3 down + BUTTON3_RELEASED mouse button 3 up + BUTTON3_CLICKED mouse button 3 clicked + BUTTON3_DOUBLE_CLICKED mouse button 3 double clicked + BUTTON3_TRIPLE_CLICKED mouse button 3 triple clicked + BUTTON4_PRESSED mouse button 4 down + BUTTON4_RELEASED mouse button 4 up + BUTTON4_CLICKED mouse button 4 clicked + BUTTON4_DOUBLE_CLICKED mouse button 4 double clicked + BUTTON4_TRIPLE_CLICKED mouse button 4 triple clicked + BUTTON_SHIFT shift was down during button state change + BUTTON_CTRL control was down during button state change + BUTTON_ALT alt was down during button state change + ALL_MOUSE_EVENTS report all button state changes + REPORT_MOUSE_POSITION report mouse movement</font> +</pre></td> +</tr> +</table> +</div> +<div class="SECT2"> +<hr> +<h3 class="SECT2"><a name="GETTINGEVENTS" id="GETTINGEVENTS">12.2. +Getting the events</a></h3> +<p>Once a class of mouse events have been enabled, getch() class of +functions return KEY_MOUSE every time some mouse event happens. +Then the mouse event can be retrieved with <var class= +"LITERAL">getmouse()</var>.</p> +<p>The code approximately looks like this:</p> +<table border="0" bgcolor="#E0E0E0" width="100%"> +<tr> +<td> +<pre class="PROGRAMLISTING"> +<font color="#000000"> MEVENT event; + + ch = getch(); + if(ch == KEY_MOUSE) + if(getmouse(&event) == OK) + . /* Do some thing with the event */ + . + .</font> +</pre></td> +</tr> +</table> +<p>getmouse() returns the event into the pointer given to it. It's +a structure which contains</p> +<table border="0" bgcolor="#E0E0E0" width="100%"> +<tr> +<td> +<pre class="PROGRAMLISTING"> +<font color="#000000"> typedef struct + { + short id; /* ID to distinguish multiple devices */ + int x, y, z; /* event coordinates */ + mmask_t bstate; /* button state bits */ + } </font> +</pre></td> +</tr> +</table> +<p>The <var class="LITERAL">bstate</var> is the main variable we +are interested in. It tells the button state of the mouse.</p> +<p>Then with a code snippet like the following, we can find out +what happened.</p> +<table border="0" bgcolor="#E0E0E0" width="100%"> +<tr> +<td> +<pre class="PROGRAMLISTING"> +<font color="#000000"> if(event.bstate & BUTTON1_PRESSED) + printw("Left Button Pressed");</font> +</pre></td> +</tr> +</table> +</div> +<div class="SECT2"> +<hr> +<h3 class="SECT2"><a name="MOUSETOGETHER" id="MOUSETOGETHER">12.3. +Putting it all Together</a></h3> +<p>That's pretty much interfacing with mouse. Let's create the same +menu and enable mouse interaction. To make things simpler, key +handling is removed.</p> +<div class="EXAMPLE"><a name="BMOME" id="BMOME"></a> +<p><b>Example 11. Access the menu with mouse !!!</b></p> +<table border="0" bgcolor="#E0E0E0" width="100%"> +<tr> +<td> +<pre class="PROGRAMLISTING"> +<font color="#000000"><span class= +"INLINEMEDIAOBJECT">#include <ncurses.h> + +#define WIDTH 30 +#define HEIGHT 10 + +int startx = 0; +int starty = 0; + +char *choices[] = { "Choice 1", + "Choice 2", + "Choice 3", + "Choice 4", + "Exit", + }; + +int n_choices = sizeof(choices) / sizeof(char *); + +void print_menu(WINDOW *menu_win, int highlight); +void report_choice(int mouse_x, int mouse_y, int *p_choice); + +int main() +{ int c, choice = 0; + WINDOW *menu_win; + MEVENT event; + + /* Initialize curses */ + initscr(); + clear(); + noecho(); + cbreak(); //Line buffering disabled. pass on everything + + /* Try to put the window in the middle of screen */ + startx = (80 - WIDTH) / 2; + starty = (24 - HEIGHT) / 2; + + attron(A_REVERSE); + mvprintw(23, 1, "Click on Exit to quit (Works best in a virtual console)"); + refresh(); + attroff(A_REVERSE); + + /* Print the menu for the first time */ + menu_win = newwin(HEIGHT, WIDTH, starty, startx); + print_menu(menu_win, 1); + /* Get all the mouse events */ + mousemask(ALL_MOUSE_EVENTS, NULL); + + while(1) + { c = wgetch(menu_win); + switch(c) + { case KEY_MOUSE: + if(getmouse(&event) == OK) + { /* When the user clicks left mouse button */ + if(event.bstate & BUTTON1_PRESSED) + { report_choice(event.x + 1, event.y + 1, &choice); + if(choice == -1) //Exit chosen + goto end; + mvprintw(22, 1, "Choice made is : %d String Chosen is \"%10s\"", choice, choices[choice - 1]); + refresh(); + } + } + print_menu(menu_win, choice); + break; + } + } +end: + endwin(); + return 0; +} + + +void print_menu(WINDOW *menu_win, int highlight) +{ + int x, y, i; + + x = 2; + y = 2; + box(menu_win, 0, 0); + for(i = 0; i < n_choices; ++i) + { if(highlight == i + 1) + { wattron(menu_win, A_REVERSE); + mvwprintw(menu_win, y, x, "%s", choices[i]); + wattroff(menu_win, A_REVERSE); + } + else + mvwprintw(menu_win, y, x, "%s", choices[i]); + ++y; + } + wrefresh(menu_win); +} + +/* Report the choice according to mouse position */ +void report_choice(int mouse_x, int mouse_y, int *p_choice) +{ int i,j, choice; + + i = startx + 2; + j = starty + 3; + + for(choice = 0; choice < n_choices; ++choice) + if(mouse_y == j + choice && mouse_x >= i && mouse_x <= i + strlen(choices[choice])) + { if(choice == n_choices - 1) + *p_choice = -1; + else + *p_choice = choice + 1; + break; + } +}</span></font> +</pre></td> +</tr> +</table> +</div> +</div> +<div class="SECT2"> +<hr> +<h3 class="SECT2"><a name="MISCMOUSEFUNCS" id= +"MISCMOUSEFUNCS">12.4. Miscellaneous Functions</a></h3> +<p>The functions mouse_trafo() and wmouse_trafo() can be used to +convert to mouse co-ordinates to screen relative co-ordinates. See +curs_mouse(3X) man page for details.</p> +<p>The mouseinterval function sets the maximum time (in thousands +of a second) that can elapse between press and release events in +order for them to be recognized as a click. This function returns +the previous interval value. The default is one fifth of a +second.</p> +</div> +</div> +<div class="SECT1"> +<hr> +<h2 class="SECT1"><a name="SCREEN" id="SCREEN">13. Screen +Manipulation</a></h2> +<p>In this section, we will look into some functions, which allow +us to manage the screen efficiently and to write some fancy +programs. This is especially important in writing games.</p> +<div class="SECT2"> +<hr> +<h3 class="SECT2"><a name="GETYX" id="GETYX">13.1. getyx() +functions</a></h3> +<p>The function <var class="LITERAL">getyx()</var> can be used to +find out the present cursor co-ordinates. It will fill the values +of x and y co-ordinates in the arguments given to it. Since getyx() +is a macro you don't have to pass the address of the variables. It +can be called as</p> +<table border="0" bgcolor="#E0E0E0" width="100%"> +<tr> +<td> +<pre class="PROGRAMLISTING"> +<font color="#000000"> getyx(win, y, x); + /* win: window pointer + * y, x: y, x co-ordinates will be put into this variables + */</font> +</pre></td> +</tr> +</table> +<p>The function getparyx() gets the beginning co-ordinates of the +sub window relative to the main window. This is some times useful +to update a sub window. When designing fancy stuff like writing +multiple menus, it becomes difficult to store the menu positions, +their first option co-ordinates etc. A simple solution to this +problem, is to create menus in sub windows and later find the +starting co-ordinates of the menus by using getparyx().</p> +<p>The functions getbegyx() and getmaxyx() store current window's +beginning and maximum co-ordinates. These functions are useful in +the same way as above in managing the windows and sub windows +effectively.</p> +</div> +<div class="SECT2"> +<hr> +<h3 class="SECT2"><a name="SCREENDUMP" id="SCREENDUMP">13.2. Screen +Dumping</a></h3> +<p>While writing games, some times it becomes necessary to store +the state of the screen and restore it back to the same state. The +function scr_dump() can be used to dump the screen contents to a +file given as an argument. Later it can be restored by scr_restore +function. These two simple functions can be used effectively to +maintain a fast moving game with changing scenarios.</p> +</div> +<div class="SECT2"> +<hr> +<h3 class="SECT2"><a name="WINDOWDUMP" id="WINDOWDUMP">13.3. Window +Dumping</a></h3> +<p>To store and restore windows, the functions <var class= +"LITERAL">putwin()</var> and <var class="LITERAL">getwin()</var> +can be used. <var class="LITERAL">putwin()</var> puts the present +window state into a file, which can be later restored by +<var class="LITERAL">getwin()</var>.</p> +<p>The function <var class="LITERAL">copywin()</var> can be used to +copy a window completely onto another window. It takes the source +and destination windows as parameters and according to the +rectangle specified, it copies the rectangular region from source +to destination window. It's last parameter specifies whether to +overwrite or just overlay the contents on to the destination +window. If this argument is true, then the copying is +non-destructive.</p> +</div> +</div> +<div class="SECT1"> +<hr> +<h2 class="SECT1"><a name="MISC" id="MISC">14. Miscellaneous +features</a></h2> +<p>Now you know enough features to write a good curses program, +with all bells and whistles. There are some miscellaneous functions +which are useful in various cases. Let's go headlong into some of +those.</p> +<div class="SECT2"> +<hr> +<h3 class="SECT2"><a name="CURSSET" id="CURSSET">14.1. +curs_set()</a></h3> +<p>This function can be used to make the cursor invisible. The +parameter to this function should be</p> +<table border="0" bgcolor="#E0E0E0" width="100%"> +<tr> +<td> +<pre class="PROGRAMLISTING"> +<font color="#000000"> 0 : invisible or + 1 : normal or + 2 : very visible.</font> +</pre></td> +</tr> +</table> +</div> +<div class="SECT2"> +<hr> +<h3 class="SECT2"><a name="TEMPLEAVE" id="TEMPLEAVE">14.2. +Temporarily Leaving Curses mode</a></h3> +<p>Some times you may want to get back to cooked mode (normal line +buffering mode) temporarily. In such a case you will first need to +save the tty modes with a call to <var class= +"LITERAL">def_prog_mode()</var> and then call <var class= +"LITERAL">endwin()</var> to end the curses mode. This will leave +you in the original tty mode. To get back to curses once you are +done, call <var class="LITERAL">reset_prog_mode()</var> . This +function returns the tty to the state stored by <var class= +"LITERAL">def_prog_mode()</var>. Then do refresh(), and you are +back to the curses mode. Here is an example showing the sequence of +things to be done.</p> +<div class="EXAMPLE"><a name="BTELE" id="BTELE"></a> +<p><b>Example 12. Temporarily Leaving Curses Mode</b></p> +<table border="0" bgcolor="#E0E0E0" width="100%"> +<tr> +<td> +<pre class="PROGRAMLISTING"> +<font color="#000000"><span class= +"INLINEMEDIAOBJECT">#include <ncurses.h> + +int main() +{ + initscr(); /* Start curses mode */ + printw("Hello World !!!\n"); /* Print Hello World */ + refresh(); /* Print it on to the real screen */ + def_prog_mode(); /* Save the tty modes */ + endwin(); /* End curses mode temporarily */ + system("/bin/sh"); /* Do whatever you like in cooked mode */ + reset_prog_mode(); /* Return to the previous tty mode*/ + /* stored by def_prog_mode() */ + refresh(); /* Do refresh() to restore the */ + /* Screen contents */ + printw("Another String\n"); /* Back to curses use the full */ + refresh(); /* capabilities of curses */ + endwin(); /* End curses mode */ + + return 0; +}</span></font> +</pre></td> +</tr> +</table> +</div> +</div> +<div class="SECT2"> +<hr> +<h3 class="SECT2"><a name="ACSVARS" id="ACSVARS">14.3. ACS_ +variables</a></h3> +<p>If you have ever programmed in DOS, you know about those nifty +characters in extended character set. They are printable only on +some terminals. NCURSES functions like <var class= +"LITERAL">box()</var> use these characters. All these variables +start with ACS meaning alternative character set. You might have +noticed me using these characters in some of the programs above. +Here's an example showing all the characters.</p> +<div class="EXAMPLE"><a name="BACSVARS" id="BACSVARS"></a> +<p><b>Example 13. ACS Variables Example</b></p> +<table border="0" bgcolor="#E0E0E0" width="100%"> +<tr> +<td> +<pre class="PROGRAMLISTING"> +<font color="#000000"><span class= +"INLINEMEDIAOBJECT">#include <ncurses.h> + +int main() +{ + initscr(); + + printw("Upper left corner "); addch(ACS_ULCORNER); printw("\n"); + printw("Lower left corner "); addch(ACS_LLCORNER); printw("\n"); + printw("Lower right corner "); addch(ACS_LRCORNER); printw("\n"); + printw("Tee pointing right "); addch(ACS_LTEE); printw("\n"); + printw("Tee pointing left "); addch(ACS_RTEE); printw("\n"); + printw("Tee pointing up "); addch(ACS_BTEE); printw("\n"); + printw("Tee pointing down "); addch(ACS_TTEE); printw("\n"); + printw("Horizontal line "); addch(ACS_HLINE); printw("\n"); + printw("Vertical line "); addch(ACS_VLINE); printw("\n"); + printw("Large Plus or cross over "); addch(ACS_PLUS); printw("\n"); + printw("Scan Line 1 "); addch(ACS_S1); printw("\n"); + printw("Scan Line 3 "); addch(ACS_S3); printw("\n"); + printw("Scan Line 7 "); addch(ACS_S7); printw("\n"); + printw("Scan Line 9 "); addch(ACS_S9); printw("\n"); + printw("Diamond "); addch(ACS_DIAMOND); printw("\n"); + printw("Checker board (stipple) "); addch(ACS_CKBOARD); printw("\n"); + printw("Degree Symbol "); addch(ACS_DEGREE); printw("\n"); + printw("Plus/Minus Symbol "); addch(ACS_PLMINUS); printw("\n"); + printw("Bullet "); addch(ACS_BULLET); printw("\n"); + printw("Arrow Pointing Left "); addch(ACS_LARROW); printw("\n"); + printw("Arrow Pointing Right "); addch(ACS_RARROW); printw("\n"); + printw("Arrow Pointing Down "); addch(ACS_DARROW); printw("\n"); + printw("Arrow Pointing Up "); addch(ACS_UARROW); printw("\n"); + printw("Board of squares "); addch(ACS_BOARD); printw("\n"); + printw("Lantern Symbol "); addch(ACS_LANTERN); printw("\n"); + printw("Solid Square Block "); addch(ACS_BLOCK); printw("\n"); + printw("Less/Equal sign "); addch(ACS_LEQUAL); printw("\n"); + printw("Greater/Equal sign "); addch(ACS_GEQUAL); printw("\n"); + printw("Pi "); addch(ACS_PI); printw("\n"); + printw("Not equal "); addch(ACS_NEQUAL); printw("\n"); + printw("UK pound sign "); addch(ACS_STERLING); printw("\n"); + + refresh(); + getch(); + endwin(); + + return 0; +}</span></font> +</pre></td> +</tr> +</table> +</div> +</div> +</div> +<div class="SECT1"> +<hr> +<h2 class="SECT1"><a name="OTHERLIB" id="OTHERLIB">15. Other +libraries</a></h2> +<p>Apart from the curses library, there are few text mode +libraries, which provide more functionality and a lot of features. +The following sections explain three standard libraries which are +usually distributed along with curses.</p> +</div> +<div class="SECT1"> +<hr> +<h2 class="SECT1"><a name="PANELS" id="PANELS">16. Panel +Library</a></h2> +<p>Now that you are proficient in curses, you wanted to do some +thing big. You created a lot of overlapping windows to give a +professional windows-type look. Unfortunately, it soon becomes +difficult to manage these. The multiple refreshes, updates plunge +you into a nightmare. The overlapping windows create blotches, +whenever you forget to refresh the windows in the proper order.</p> +<p>Don't despair. There's an elegant solution provided in panels +library. In the words of developers of ncurses</p> +<p><em>When your interface design is such that windows may dive +deeper into the visibility stack or pop to the top at runtime, the +resulting book-keeping can be tedious and difficult to get right. +Hence the panels library.</em></p> +<p>If you have lot of overlapping windows, then panels library is +the way to go. It obviates the need of doing series of +wnoutrefresh(), doupdate() and relieves the burden of doing it +correctly(bottom up). The library maintains information about the +order of windows, their overlapping and update the screen properly. +So why wait? Let's take a close peek into panels.</p> +<div class="SECT2"> +<hr> +<h3 class="SECT2"><a name="PANELBASICS" id="PANELBASICS">16.1. The +Basics</a></h3> +<p>Panel object is a window that is implicitly treated as part of a +deck including all other panel objects. The deck is treated as a +stack with the top panel being completely visible and the other +panels may or may not be obscured according to their positions. So +the basic idea is to create a stack of overlapping panels and use +panels library to display them correctly. There is a function +similar to refresh() which, when called , displays panels in the +correct order. Functions are provided to hide or show panels, move +panels, change its size etc.. The overlapping problem is managed by +the panels library during all the calls to these functions.</p> +<p>The general flow of a panel program goes like this:</p> +<ol type="1"> +<li> +<p>Create the windows (with newwin()) to be attached to the +panels.</p> +</li> +<li> +<p>Create panels with the chosen visibility order. Stack them up +according to the desired visibility. The function new_panel() is +used to created panels.</p> +</li> +<li> +<p>Call update_panels() to write the panels to the virtual screen +in correct visibility order. Do a doupdate() to show it on the +screen.</p> +</li> +<li> +<p>Mainpulate the panels with show_panel(), hide_panel(), +move_panel() etc. Make use of helper functions like panel_hidden() +and panel_window(). Make use of user pointer to store custom data +for a panel. Use the functions set_panel_userptr() and +panel_userptr() to set and get the user pointer for a panel.</p> +</li> +<li> +<p>When you are done with the panel use del_panel() to delete the +panel.</p> +</li> +</ol> +<p>Let's make the concepts clear, with some programs. The following +is a simple program which creates 3 overlapping panels and shows +them on the screen.</p> +</div> +<div class="SECT2"> +<hr> +<h3 class="SECT2"><a name="COMPILEPANELS" id="COMPILEPANELS">16.2. +Compiling With the Panels Library</a></h3> +<p>To use panels library functions, you have to include panel.h and +to link the program with panels library the flag -lpanel should be +added along with -lncurses in that order.</p> +<table border="0" bgcolor="#E0E0E0" width="100%"> +<tr> +<td> +<pre class="PROGRAMLISTING"> +<font color="#000000"> #include <panel.h> + . + . + . + + compile and link: gcc <program file> -lpanel -lncurses</font> +</pre></td> +</tr> +</table> +<div class="EXAMPLE"><a name="PPASI" id="PPASI"></a> +<p><b>Example 14. Panel basics</b></p> +<table border="0" bgcolor="#E0E0E0" width="100%"> +<tr> +<td> +<pre class="PROGRAMLISTING"> +<font color="#000000"><span class= +"INLINEMEDIAOBJECT">#include <panel.h> + +int main() +{ WINDOW *my_wins[3]; + PANEL *my_panels[3]; + int lines = 10, cols = 40, y = 2, x = 4, i; + + initscr(); + cbreak(); + noecho(); + + /* Create windows for the panels */ + my_wins[0] = newwin(lines, cols, y, x); + my_wins[1] = newwin(lines, cols, y + 1, x + 5); + my_wins[2] = newwin(lines, cols, y + 2, x + 10); + + /* + * Create borders around the windows so that you can see the effect + * of panels + */ + for(i = 0; i < 3; ++i) + box(my_wins[i], 0, 0); + + /* Attach a panel to each window */ /* Order is bottom up */ + my_panels[0] = new_panel(my_wins[0]); /* Push 0, order: stdscr-0 */ + my_panels[1] = new_panel(my_wins[1]); /* Push 1, order: stdscr-0-1 */ + my_panels[2] = new_panel(my_wins[2]); /* Push 2, order: stdscr-0-1-2 */ + + /* Update the stacking order. 2nd panel will be on top */ + update_panels(); + + /* Show it on the screen */ + doupdate(); + + getch(); + endwin(); +} +</span></font> +</pre></td> +</tr> +</table> +</div> +<p>As you can see, above program follows a simple flow as +explained. The windows are created with newwin() and then they are +attached to panels with new_panel(). As we attach one panel after +another, the stack of panels gets updated. To put them on screen +update_panels() and doupdate() are called.</p> +</div> +<div class="SECT2"> +<hr> +<h3 class="SECT2"><a name="PANELBROWSING" id="PANELBROWSING">16.3. +Panel Window Browsing</a></h3> +<p>A slightly complicated example is given below. This program +creates 3 windows which can be cycled through using tab. Have a +look at the code.</p> +<div class="EXAMPLE"><a name="PPABR" id="PPABR"></a> +<p><b>Example 15. Panel Window Browsing Example</b></p> +<table border="0" bgcolor="#E0E0E0" width="100%"> +<tr> +<td> +<pre class="PROGRAMLISTING"> +<font color="#000000"><span class= +"INLINEMEDIAOBJECT">#include <panel.h> + +#define NLINES 10 +#define NCOLS 40 + +void init_wins(WINDOW **wins, int n); +void win_show(WINDOW *win, char *label, int label_color); +void print_in_middle(WINDOW *win, int starty, int startx, int width, char *string, chtype color); + +int main() +{ WINDOW *my_wins[3]; + PANEL *my_panels[3]; + PANEL *top; + int ch; + + /* Initialize curses */ + initscr(); + start_color(); + cbreak(); + noecho(); + keypad(stdscr, TRUE); + + /* Initialize all the colors */ + init_pair(1, COLOR_RED, COLOR_BLACK); + init_pair(2, COLOR_GREEN, COLOR_BLACK); + init_pair(3, COLOR_BLUE, COLOR_BLACK); + init_pair(4, COLOR_CYAN, COLOR_BLACK); + + init_wins(my_wins, 3); + + /* Attach a panel to each window */ /* Order is bottom up */ + my_panels[0] = new_panel(my_wins[0]); /* Push 0, order: stdscr-0 */ + my_panels[1] = new_panel(my_wins[1]); /* Push 1, order: stdscr-0-1 */ + my_panels[2] = new_panel(my_wins[2]); /* Push 2, order: stdscr-0-1-2 */ + + /* Set up the user pointers to the next panel */ + set_panel_userptr(my_panels[0], my_panels[1]); + set_panel_userptr(my_panels[1], my_panels[2]); + set_panel_userptr(my_panels[2], my_panels[0]); + + /* Update the stacking order. 2nd panel will be on top */ + update_panels(); + + /* Show it on the screen */ + attron(COLOR_PAIR(4)); + mvprintw(LINES - 2, 0, "Use tab to browse through the windows (F1 to Exit)"); + attroff(COLOR_PAIR(4)); + doupdate(); + + top = my_panels[2]; + while((ch = getch()) != KEY_F(1)) + { switch(ch) + { case 9: + top = (PANEL *)panel_userptr(top); + top_panel(top); + break; + } + update_panels(); + doupdate(); + } + endwin(); + return 0; +} + +/* Put all the windows */ +void init_wins(WINDOW **wins, int n) +{ int x, y, i; + char label[80]; + + y = 2; + x = 10; + for(i = 0; i < n; ++i) + { wins[i] = newwin(NLINES, NCOLS, y, x); + sprintf(label, "Window Number %d", i + 1); + win_show(wins[i], label, i + 1); + y += 3; + x += 7; + } +} + +/* Show the window with a border and a label */ +void win_show(WINDOW *win, char *label, int label_color) +{ int startx, starty, height, width; + + getbegyx(win, starty, startx); + getmaxyx(win, height, width); + + box(win, 0, 0); + mvwaddch(win, 2, 0, ACS_LTEE); + mvwhline(win, 2, 1, ACS_HLINE, width - 2); + mvwaddch(win, 2, width - 1, ACS_RTEE); + + print_in_middle(win, 1, 0, width, label, COLOR_PAIR(label_color)); +} + +void print_in_middle(WINDOW *win, int starty, int startx, int width, char *string, chtype color) +{ int length, x, y; + float temp; + + if(win == NULL) + win = stdscr; + getyx(win, y, x); + if(startx != 0) + x = startx; + if(starty != 0) + y = starty; + if(width == 0) + width = 80; + + length = strlen(string); + temp = (width - length)/ 2; + x = startx + (int)temp; + wattron(win, color); + mvwprintw(win, y, x, "%s", string); + wattroff(win, color); + refresh(); +}</span></font> +</pre></td> +</tr> +</table> +</div> +</div> +<div class="SECT2"> +<hr> +<h3 class="SECT2"><a name="USERPTRUSING" id="USERPTRUSING">16.4. +Using User Pointers</a></h3> +<p>In the above example I used user pointers to find out the next +window in the cycle. We can attach custom information to the panel +by specifying a user pointer, which can point to any information +you want to store. In this case I stored the pointer to the next +panel in the cycle. User pointer for a panel can be set with the +function <var class="LITERAL">set_panel_userptr()</var>. It can be +accessed using the function <var class= +"LITERAL">panel_userptr()</var> which will return the user pointer +for the panel given as argument. After finding the next panel in +the cycle It's brought to the top by the function top_panel(). This +function brings the panel given as argument to the top of the panel +stack.</p> +</div> +<div class="SECT2"> +<hr> +<h3 class="SECT2"><a name="PANELMOVERESIZE" id= +"PANELMOVERESIZE">16.5. Moving and Resizing Panels</a></h3> +<p>The function <var class="LITERAL">move_panel()</var> can be used +to move a panel to the desired location. It does not change the +position of the panel in the stack. Make sure that you use +move_panel() instead mvwin() on the window associated with the +panel.</p> +<p>Resizing a panel is slightly complex. There is no straight +forward function just to resize the window associated with a panel. +A solution to resize a panel is to create a new window with the +desired sizes, change the window associated with the panel using +replace_panel(). Don't forget to delete the old window. The window +associated with a panel can be found by using the function +panel_window().</p> +<p>The following program shows these concepts, in supposedly simple +program. You can cycle through the window with <TAB> as +usual. To resize or move the active panel press 'r' for resize 'm' +for moving. Then use arrow keys to resize or move it to the desired +way and press enter to end your resizing or moving. This example +makes use of user data to get the required data to do the +operations.</p> +<div class="EXAMPLE"><a name="PPARE" id="PPARE"></a> +<p><b>Example 16. Panel Moving and Resizing example</b></p> +<table border="0" bgcolor="#E0E0E0" width="100%"> +<tr> +<td> +<pre class="PROGRAMLISTING"> +<font color="#000000"><span class= +"INLINEMEDIAOBJECT">#include <panel.h> + +typedef struct _PANEL_DATA { + int x, y, w, h; + char label[80]; + int label_color; + PANEL *next; +}PANEL_DATA; + +#define NLINES 10 +#define NCOLS 40 + +void init_wins(WINDOW **wins, int n); +void win_show(WINDOW *win, char *label, int label_color); +void print_in_middle(WINDOW *win, int starty, int startx, int width, char *string, chtype color); +void set_user_ptrs(PANEL **panels, int n); + +int main() +{ WINDOW *my_wins[3]; + PANEL *my_panels[3]; + PANEL_DATA *top; + PANEL *stack_top; + WINDOW *temp_win, *old_win; + int ch; + int newx, newy, neww, newh; + int size = FALSE, move = FALSE; + + /* Initialize curses */ + initscr(); + start_color(); + cbreak(); + noecho(); + keypad(stdscr, TRUE); + + /* Initialize all the colors */ + init_pair(1, COLOR_RED, COLOR_BLACK); + init_pair(2, COLOR_GREEN, COLOR_BLACK); + init_pair(3, COLOR_BLUE, COLOR_BLACK); + init_pair(4, COLOR_CYAN, COLOR_BLACK); + + init_wins(my_wins, 3); + + /* Attach a panel to each window */ /* Order is bottom up */ + my_panels[0] = new_panel(my_wins[0]); /* Push 0, order: stdscr-0 */ + my_panels[1] = new_panel(my_wins[1]); /* Push 1, order: stdscr-0-1 */ + my_panels[2] = new_panel(my_wins[2]); /* Push 2, order: stdscr-0-1-2 */ + + set_user_ptrs(my_panels, 3); + /* Update the stacking order. 2nd panel will be on top */ + update_panels(); + + /* Show it on the screen */ + attron(COLOR_PAIR(4)); + mvprintw(LINES - 3, 0, "Use 'm' for moving, 'r' for resizing"); + mvprintw(LINES - 2, 0, "Use tab to browse through the windows (F1 to Exit)"); + attroff(COLOR_PAIR(4)); + doupdate(); + + stack_top = my_panels[2]; + top = (PANEL_DATA *)panel_userptr(stack_top); + newx = top->x; + newy = top->y; + neww = top->w; + newh = top->h; + while((ch = getch()) != KEY_F(1)) + { switch(ch) + { case 9: /* Tab */ + top = (PANEL_DATA *)panel_userptr(stack_top); + top_panel(top->next); + stack_top = top->next; + top = (PANEL_DATA *)panel_userptr(stack_top); + newx = top->x; + newy = top->y; + neww = top->w; + newh = top->h; + break; + case 'r': /* Re-Size*/ + size = TRUE; + attron(COLOR_PAIR(4)); + mvprintw(LINES - 4, 0, "Entered Resizing :Use Arrow Keys to resize and press <ENTER> to end resizing"); + refresh(); + attroff(COLOR_PAIR(4)); + break; + case 'm': /* Move */ + attron(COLOR_PAIR(4)); + mvprintw(LINES - 4, 0, "Entered Moving: Use Arrow Keys to Move and press <ENTER> to end moving"); + refresh(); + attroff(COLOR_PAIR(4)); + move = TRUE; + break; + case KEY_LEFT: + if(size == TRUE) + { --newx; + ++neww; + } + if(move == TRUE) + --newx; + break; + case KEY_RIGHT: + if(size == TRUE) + { ++newx; + --neww; + } + if(move == TRUE) + ++newx; + break; + case KEY_UP: + if(size == TRUE) + { --newy; + ++newh; + } + if(move == TRUE) + --newy; + break; + case KEY_DOWN: + if(size == TRUE) + { ++newy; + --newh; + } + if(move == TRUE) + ++newy; + break; + case 10: /* Enter */ + move(LINES - 4, 0); + clrtoeol(); + refresh(); + if(size == TRUE) + { old_win = panel_window(stack_top); + temp_win = newwin(newh, neww, newy, newx); + replace_panel(stack_top, temp_win); + win_show(temp_win, top->label, top->label_color); + delwin(old_win); + size = FALSE; + } + if(move == TRUE) + { move_panel(stack_top, newy, newx); + move = FALSE; + } + break; + + } + attron(COLOR_PAIR(4)); + mvprintw(LINES - 3, 0, "Use 'm' for moving, 'r' for resizing"); + mvprintw(LINES - 2, 0, "Use tab to browse through the windows (F1 to Exit)"); + attroff(COLOR_PAIR(4)); + refresh(); + update_panels(); + doupdate(); + } + endwin(); + return 0; +} + +/* Put all the windows */ +void init_wins(WINDOW **wins, int n) +{ int x, y, i; + char label[80]; + + y = 2; + x = 10; + for(i = 0; i < n; ++i) + { wins[i] = newwin(NLINES, NCOLS, y, x); + sprintf(label, "Window Number %d", i + 1); + win_show(wins[i], label, i + 1); + y += 3; + x += 7; + } +} + +/* Set the PANEL_DATA structures for individual panels */ +void set_user_ptrs(PANEL **panels, int n) +{ PANEL_DATA *ptrs; + WINDOW *win; + int x, y, w, h, i; + char temp[80]; + + ptrs = (PANEL_DATA *)calloc(n, sizeof(PANEL_DATA)); + + for(i = 0;i < n; ++i) + { win = panel_window(panels[i]); + getbegyx(win, y, x); + getmaxyx(win, h, w); + ptrs[i].x = x; + ptrs[i].y = y; + ptrs[i].w = w; + ptrs[i].h = h; + sprintf(temp, "Window Number %d", i + 1); + strcpy(ptrs[i].label, temp); + ptrs[i].label_color = i + 1; + if(i + 1 == n) + ptrs[i].next = panels[0]; + else + ptrs[i].next = panels[i + 1]; + set_panel_userptr(panels[i], &ptrs[i]); + } +} + +/* Show the window with a border and a label */ +void win_show(WINDOW *win, char *label, int label_color) +{ int startx, starty, height, width; + + getbegyx(win, starty, startx); + getmaxyx(win, height, width); + + box(win, 0, 0); + mvwaddch(win, 2, 0, ACS_LTEE); + mvwhline(win, 2, 1, ACS_HLINE, width - 2); + mvwaddch(win, 2, width - 1, ACS_RTEE); + + print_in_middle(win, 1, 0, width, label, COLOR_PAIR(label_color)); +} + +void print_in_middle(WINDOW *win, int starty, int startx, int width, char *string, chtype color) +{ int length, x, y; + float temp; + + if(win == NULL) + win = stdscr; + getyx(win, y, x); + if(startx != 0) + x = startx; + if(starty != 0) + y = starty; + if(width == 0) + width = 80; + + length = strlen(string); + temp = (width - length)/ 2; + x = startx + (int)temp; + wattron(win, color); + mvwprintw(win, y, x, "%s", string); + wattroff(win, color); + refresh(); +}</span></font> +</pre></td> +</tr> +</table> +</div> +<p>Concentrate on the main while loop. Once it finds out the type +of key pressed, it takes appropriate action. If 'r' is pressed +resizing mode is started. After this the new sizes are updated as +the user presses the arrow keys. When the user presses +<ENTER> present selection ends and panel is resized by using +the concept explained. While in resizing mode the program doesn't +show how the window is getting resized. It's left as an exercise to +the reader to print a dotted border while it gets resized to a new +position.</p> +<p>When the user presses 'm' the move mode starts. This is a bit +simpler than resizing. As the arrow keys are pressed the new +position is updated and pressing of <ENTER> causes the panel +to be moved by calling the function move_panel().</p> +<p>In this program the user data which is represented as +PANEL_DATA, plays very important role in finding the associated +information with a panel. As written in the comments, the +PANEL_DATA stores the panel sizes, label, label color and a pointer +to the next panel in the cycle.</p> +</div> +<div class="SECT2"> +<hr> +<h3 class="SECT2"><a name="PANELSHOWHIDE" id="PANELSHOWHIDE">16.6. +Hiding and Showing Panels</a></h3> +<p>A Panel can be hidden by using the function hide_panel(). This +function merely removes it form the stack of panels, thus hiding it +on the screen once you do update_panels() and doupdate(). It +doesn't destroy the PANEL structure associated with the hidden +panel. It can be shown again by using the show_panel() +function.</p> +<p>The following program shows the hiding of panels. Press 'a' or +'b' or 'c' to show or hide first, second and third windows +respectively. It uses a user data with a small variable hide, which +keeps track of whether the window is hidden or not. For some reason +the function <var class="LITERAL">panel_hidden()</var> which tells +whether a panel is hidden or not is not working. A bug report was +also presented by Michael Andres <a href= +"http://www.geocrawler.com/archives/3/344/1999/9/0/2643549/" +target="_top">here</a></p> +<div class="EXAMPLE"><a name="PPAHI" id="PPAHI"></a> +<p><b>Example 17. Panel Hiding and Showing example</b></p> +<table border="0" bgcolor="#E0E0E0" width="100%"> +<tr> +<td> +<pre class="PROGRAMLISTING"> +<font color="#000000"><span class= +"INLINEMEDIAOBJECT">#include <panel.h> + +typedef struct _PANEL_DATA { + int hide; /* TRUE if panel is hidden */ +}PANEL_DATA; + +#define NLINES 10 +#define NCOLS 40 + +void init_wins(WINDOW **wins, int n); +void win_show(WINDOW *win, char *label, int label_color); +void print_in_middle(WINDOW *win, int starty, int startx, int width, char *string, chtype color); + +int main() +{ WINDOW *my_wins[3]; + PANEL *my_panels[3]; + PANEL_DATA panel_datas[3]; + PANEL_DATA *temp; + int ch; + + /* Initialize curses */ + initscr(); + start_color(); + cbreak(); + noecho(); + keypad(stdscr, TRUE); + + /* Initialize all the colors */ + init_pair(1, COLOR_RED, COLOR_BLACK); + init_pair(2, COLOR_GREEN, COLOR_BLACK); + init_pair(3, COLOR_BLUE, COLOR_BLACK); + init_pair(4, COLOR_CYAN, COLOR_BLACK); + + init_wins(my_wins, 3); + + /* Attach a panel to each window */ /* Order is bottom up */ + my_panels[0] = new_panel(my_wins[0]); /* Push 0, order: stdscr-0 */ + my_panels[1] = new_panel(my_wins[1]); /* Push 1, order: stdscr-0-1 */ + my_panels[2] = new_panel(my_wins[2]); /* Push 2, order: stdscr-0-1-2 */ + + /* Initialize panel datas saying that nothing is hidden */ + panel_datas[0].hide = FALSE; + panel_datas[1].hide = FALSE; + panel_datas[2].hide = FALSE; + + set_panel_userptr(my_panels[0], &panel_datas[0]); + set_panel_userptr(my_panels[1], &panel_datas[1]); + set_panel_userptr(my_panels[2], &panel_datas[2]); + + /* Update the stacking order. 2nd panel will be on top */ + update_panels(); + + /* Show it on the screen */ + attron(COLOR_PAIR(4)); + mvprintw(LINES - 3, 0, "Show or Hide a window with 'a'(first window) 'b'(Second Window) 'c'(Third Window)"); + mvprintw(LINES - 2, 0, "F1 to Exit"); + + attroff(COLOR_PAIR(4)); + doupdate(); + + while((ch = getch()) != KEY_F(1)) + { switch(ch) + { case 'a': + temp = (PANEL_DATA *)panel_userptr(my_panels[0]); + if(temp->hide == FALSE) + { hide_panel(my_panels[0]); + temp->hide = TRUE; + } + else + { show_panel(my_panels[0]); + temp->hide = FALSE; + } + break; + case 'b': + temp = (PANEL_DATA *)panel_userptr(my_panels[1]); + if(temp->hide == FALSE) + { hide_panel(my_panels[1]); + temp->hide = TRUE; + } + else + { show_panel(my_panels[1]); + temp->hide = FALSE; + } + break; + case 'c': + temp = (PANEL_DATA *)panel_userptr(my_panels[2]); + if(temp->hide == FALSE) + { hide_panel(my_panels[2]); + temp->hide = TRUE; + } + else + { show_panel(my_panels[2]); + temp->hide = FALSE; + } + break; + } + update_panels(); + doupdate(); + } + endwin(); + return 0; +} + +/* Put all the windows */ +void init_wins(WINDOW **wins, int n) +{ int x, y, i; + char label[80]; + + y = 2; + x = 10; + for(i = 0; i < n; ++i) + { wins[i] = newwin(NLINES, NCOLS, y, x); + sprintf(label, "Window Number %d", i + 1); + win_show(wins[i], label, i + 1); + y += 3; + x += 7; + } +} + +/* Show the window with a border and a label */ +void win_show(WINDOW *win, char *label, int label_color) +{ int startx, starty, height, width; + + getbegyx(win, starty, startx); + getmaxyx(win, height, width); + + box(win, 0, 0); + mvwaddch(win, 2, 0, ACS_LTEE); + mvwhline(win, 2, 1, ACS_HLINE, width - 2); + mvwaddch(win, 2, width - 1, ACS_RTEE); + + print_in_middle(win, 1, 0, width, label, COLOR_PAIR(label_color)); +} + +void print_in_middle(WINDOW *win, int starty, int startx, int width, char *string, chtype color) +{ int length, x, y; + float temp; + + if(win == NULL) + win = stdscr; + getyx(win, y, x); + if(startx != 0) + x = startx; + if(starty != 0) + y = starty; + if(width == 0) + width = 80; + + length = strlen(string); + temp = (width - length)/ 2; + x = startx + (int)temp; + wattron(win, color); + mvwprintw(win, y, x, "%s", string); + wattroff(win, color); + refresh(); +}</span></font> +</pre></td> +</tr> +</table> +</div> +</div> +<div class="SECT2"> +<hr> +<h3 class="SECT2"><a name="PANELABOVE" id="PANELABOVE">16.7. +panel_above() and panel_below() Functions</a></h3> +<p>The functions <var class="LITERAL">panel_above()</var> and +<var class="LITERAL">panel_below()</var> can be used to find out +the panel above and below a panel. If the argument to these +functions is NULL, then they return a pointer to bottom panel and +top panel respectively.</p> +</div> +</div> +<div class="SECT1"> +<hr> +<h2 class="SECT1"><a name="MENUS" id="MENUS">17. Menus +Library</a></h2> +<p>The menus library provides a nice extension to basic curses, +through which you can create menus. It provides a set of functions +to create menus. But they have to be customized to give a nicer +look, with colors etc. Let's get into the details.</p> +<p>A menu is a screen display that assists the user to choose some +subset of a given set of items. To put it simple, a menu is a +collection of items from which one or more items can be chosen. +Some readers might not be aware of multiple item selection +capability. Menu library provides functionality to write menus from +which the user can chose more than one item as the preferred +choice. This is dealt with in a later section. Now it is time for +some rudiments.</p> +<div class="SECT2"> +<hr> +<h3 class="SECT2"><a name="MENUBASICS" id="MENUBASICS">17.1. The +Basics</a></h3> +<p>To create menus, you first create items, and then post the menu +to the display. After that, all the processing of user responses is +done in an elegant function menu_driver() which is the work horse +of any menu program.</p> +<p>The general flow of control of a menu program looks like +this.</p> +<ol type="1"> +<li> +<p>Initialize curses</p> +</li> +<li> +<p>Create items using new_item(). You can specify a name and +description for the items.</p> +</li> +<li> +<p>Create the menu with new_menu() by specifying the items to be +attached with.</p> +</li> +<li> +<p>Post the menu with menu_post() and refresh the screen.</p> +</li> +<li> +<p>Process the user requests with a loop and do necessary updates +to menu with menu_driver.</p> +</li> +<li> +<p>Unpost the menu with menu_unpost()</p> +</li> +<li> +<p>Free the memory allocated to menu by free_menu()</p> +</li> +<li> +<p>Free the memory allocated to the items with free_item()</p> +</li> +<li> +<p>End curses</p> +</li> +</ol> +<p>Let's see a program which prints a simple menu and updates the +current selection with up, down arrows.</p> +</div> +<div class="SECT2"> +<hr> +<h3 class="SECT2"><a name="COMPILEMENUS" id="COMPILEMENUS">17.2. +Compiling With the Menu Library</a></h3> +<p>To use menu library functions, you have to include menu.h and to +link the program with menu library the flag -lmenu should be added +along with -lncurses in that order.</p> +<table border="0" bgcolor="#E0E0E0" width="100%"> +<tr> +<td> +<pre class="PROGRAMLISTING"> +<font color="#000000"> #include <menu.h> + . + . + . + + compile and link: gcc <program file> -lmenu -lncurses</font> +</pre></td> +</tr> +</table> +<div class="EXAMPLE"><a name="MMESI" id="MMESI"></a> +<p><b>Example 18. Menu Basics</b></p> +<table border="0" bgcolor="#E0E0E0" width="100%"> +<tr> +<td> +<pre class="PROGRAMLISTING"> +<font color="#000000"><span class= +"INLINEMEDIAOBJECT">#include <curses.h> +#include <menu.h> + +#define ARRAY_SIZE(a) (sizeof(a) / sizeof(a[0])) +#define CTRLD 4 + +char *choices[] = { + "Choice 1", + "Choice 2", + "Choice 3", + "Choice 4", + "Exit", + }; + +int main() +{ ITEM **my_items; + int c; + MENU *my_menu; + int n_choices, i; + ITEM *cur_item; + + + initscr(); + cbreak(); + noecho(); + keypad(stdscr, TRUE); + + n_choices = ARRAY_SIZE(choices); + my_items = (ITEM **)calloc(n_choices + 1, sizeof(ITEM *)); + + for(i = 0; i < n_choices; ++i) + my_items[i] = new_item(choices[i], choices[i]); + my_items[n_choices] = (ITEM *)NULL; + + my_menu = new_menu((ITEM **)my_items); + mvprintw(LINES - 2, 0, "F1 to Exit"); + post_menu(my_menu); + refresh(); + + while((c = getch()) != KEY_F(1)) + { switch(c) + { case KEY_DOWN: + menu_driver(my_menu, REQ_DOWN_ITEM); + break; + case KEY_UP: + menu_driver(my_menu, REQ_UP_ITEM); + break; + } + } + + free_item(my_items[0]); + free_item(my_items[1]); + free_menu(my_menu); + endwin(); +} + </span></font> +</pre></td> +</tr> +</table> +</div> +<p>This program demonstrates the basic concepts involved in +creating a menu using menus library. First we create the items +using new_item() and then attach them to the menu with new_menu() +function. After posting the menu and refreshing the screen, the +main processing loop starts. It reads user input and takes +corresponding action. The function menu_driver() is the main work +horse of the menu system. The second parameter to this function +tells what's to be done with the menu. According to the parameter, +menu_driver() does the corresponding task. The value can be either +a menu navigational request, an ascii character, or a KEY_MOUSE +special key associated with a mouse event.</p> +<p>The menu_driver accepts following navigational requests.</p> +<table border="0" bgcolor="#E0E0E0" width="100%"> +<tr> +<td> +<pre class="PROGRAMLISTING"> +<font color= +"#000000"> REQ_LEFT_ITEM Move left to an item. + REQ_RIGHT_ITEM Move right to an item. + REQ_UP_ITEM Move up to an item. + REQ_DOWN_ITEM Move down to an item. + REQ_SCR_ULINE Scroll up a line. + REQ_SCR_DLINE Scroll down a line. + REQ_SCR_DPAGE Scroll down a page. + REQ_SCR_UPAGE Scroll up a page. + REQ_FIRST_ITEM Move to the first item. + REQ_LAST_ITEM Move to the last item. + REQ_NEXT_ITEM Move to the next item. + REQ_PREV_ITEM Move to the previous item. + REQ_TOGGLE_ITEM Select/deselect an item. + REQ_CLEAR_PATTERN Clear the menu pattern buffer. + REQ_BACK_PATTERN Delete the previous character from the pattern buffer. + REQ_NEXT_MATCH Move to the next item matching the pattern match. + REQ_PREV_MATCH Move to the previous item matching the pattern match. </font> +</pre></td> +</tr> +</table> +<p>Don't get overwhelmed by the number of options. We will see them +slowly one after another. The options of interest in this example +are REQ_UP_ITEM and REQ_DOWN_ITEM. These two options when passed to +menu_driver, menu driver updates the current item to one item up or +down respectively.</p> +</div> +<div class="SECT2"> +<hr> +<h3 class="SECT2"><a name="MENUDRIVER" id="MENUDRIVER">17.3. Menu +Driver: The work horse of the menu system</a></h3> +<p>As you have seen in the above example, menu_driver plays an +important role in updating the menu. It is very important to +understand various options it takes and what they do. As explained +above, the second parameter to menu_driver() can be either a +navigational request, a printable character or a KEY_MOUSE key. +Let's dissect the different navigational requests.</p> +<ul> +<li> +<p><em>REQ_LEFT_ITEM and REQ_RIGHT_ITEM</em></p> +<p>A Menu can be displayed with multiple columns for more than one +item. This can be done by using the <var class= +"LITERAL">menu_format()</var>function. When a multi columnar menu +is displayed these requests cause the menu driver to move the +current selection to left or right.</p> +</li> +<li> +<p><em>REQ_UP_ITEM and REQ_DOWN_ITEM</em></p> +<p>These two options you have seen in the above example. These +options when given, makes the menu_driver to move the current +selection to an item up or down.</p> +</li> +<li> +<p><em>REQ_SCR_* options</em></p> +<p>The four options REQ_SCR_ULINE, REQ_SCR_DLINE, REQ_SCR_DPAGE, +REQ_SCR_UPAGE are related to scrolling. If all the items in the +menu cannot be displayed in the menu sub window, then the menu is +scrollable. These requests can be given to the menu_driver to do +the scrolling either one line up, down or one page down or up +respectively.</p> +</li> +<li> +<p><em>REQ_FIRST_ITEM, REQ_LAST_ITEM, REQ_NEXT_ITEM and +REQ_PREV_ITEM</em></p> +<p>These requests are self explanatory.</p> +</li> +<li> +<p><em>REQ_TOGGLE_ITEM</em></p> +<p>This request when given, toggles the present selection. This +option is to be used only in a multi valued menu. So to use this +request the option O_ONEVALUE must be off. This option can be made +off or on with set_menu_opts().</p> +</li> +<li> +<p><em>Pattern Requests</em></p> +<p>Every menu has an associated pattern buffer, which is used to +find the nearest match to the ascii characters entered by the user. +Whenever ascii characters are given to menu_driver, it puts in to +the pattern buffer. It also tries to find the nearest match to the +pattern in the items list and moves current selection to that item. +The request REQ_CLEAR_PATTERN clears the pattern buffer. The +request REQ_BACK_PATTERN deletes the previous character in the +pattern buffer. In case the pattern matches more than one item then +the matched items can be cycled through REQ_NEXT_MATCH and +REQ_PREV_MATCH which move the current selection to the next and +previous matches respectively.</p> +</li> +<li> +<p><em>Mouse Requests</em></p> +<p>In case of KEY_MOUSE requests, according to the mouse position +an action is taken accordingly. The action to be taken is explained +in the man page as,</p> +<table border="0" bgcolor="#E0E0E0" width="90%"> +<tr> +<td> +<pre class="PROGRAMLISTING"> +<font color= +"#000000"><em> If the second argument is the KEY_MOUSE special key, the + associated mouse event is translated into one of the above + pre-defined requests. Currently only clicks in the user + window (e.g. inside the menu display area or the decora­ + tion window) are handled. If you click above the display + region of the menu, a REQ_SCR_ULINE is generated, if you + doubleclick a REQ_SCR_UPAGE is generated and if you + tripleclick a REQ_FIRST_ITEM is generated. If you click + below the display region of the menu, a REQ_SCR_DLINE is + generated, if you doubleclick a REQ_SCR_DPAGE is generated + and if you tripleclick a REQ_LAST_ITEM is generated. If + you click at an item inside the display area of the menu, + the menu cursor is positioned to that item.</em></font> +</pre></td> +</tr> +</table> +</li> +</ul> +<p>Each of the above requests will be explained in the following +lines with several examples whenever appropriate.</p> +</div> +<div class="SECT2"> +<hr> +<h3 class="SECT2"><a name="MENUWINDOWS" id="MENUWINDOWS">17.4. Menu +Windows</a></h3> +<p>Every menu created is associated with a window and a sub window. +The menu window displays any title or border associated with the +menu. The menu sub window displays the menu items currently +available for selection. But we didn't specify any window or sub +window in the simple example. When a window is not specified, +stdscr is taken as the main window, and then menu system calculates +the sub window size required for the display of items. Then items +are displayed in the calculated sub window. So let's play with +these windows and display a menu with a border and a title.</p> +<div class="EXAMPLE"><a name="MMEWI" id="MMEWI"></a> +<p><b>Example 19. Menu Windows Usage example</b></p> +<table border="0" bgcolor="#E0E0E0" width="100%"> +<tr> +<td> +<pre class="PROGRAMLISTING"> +<font color="#000000"><span class= +"INLINEMEDIAOBJECT">#include <menu.h> + +#define ARRAY_SIZE(a) (sizeof(a) / sizeof(a[0])) +#define CTRLD 4 + +char *choices[] = { + "Choice 1", + "Choice 2", + "Choice 3", + "Choice 4", + "Exit", + (char *)NULL, + }; +void print_in_middle(WINDOW *win, int starty, int startx, int width, char *string, chtype color); + +int main() +{ ITEM **my_items; + int c; + MENU *my_menu; + WINDOW *my_menu_win; + int n_choices, i; + + /* Initialize curses */ + initscr(); + start_color(); + cbreak(); + noecho(); + keypad(stdscr, TRUE); + init_pair(1, COLOR_RED, COLOR_BLACK); + + /* Create items */ + n_choices = ARRAY_SIZE(choices); + my_items = (ITEM **)calloc(n_choices, sizeof(ITEM *)); + for(i = 0; i < n_choices; ++i) + my_items[i] = new_item(choices[i], choices[i]); + + /* Crate menu */ + my_menu = new_menu((ITEM **)my_items); + + /* Create the window to be associated with the menu */ + my_menu_win = newwin(10, 40, 4, 4); + keypad(my_menu_win, TRUE); + + /* Set main window and sub window */ + set_menu_win(my_menu, my_menu_win); + set_menu_sub(my_menu, derwin(my_menu_win, 6, 38, 3, 1)); + + /* Set menu mark to the string " * " */ + set_menu_mark(my_menu, " * "); + + /* Print a border around the main window and print a title */ + box(my_menu_win, 0, 0); + print_in_middle(my_menu_win, 1, 0, 40, "My Menu", COLOR_PAIR(1)); + mvwaddch(my_menu_win, 2, 0, ACS_LTEE); + mvwhline(my_menu_win, 2, 1, ACS_HLINE, 38); + mvwaddch(my_menu_win, 2, 39, ACS_RTEE); + mvprintw(LINES - 2, 0, "F1 to exit"); + refresh(); + + /* Post the menu */ + post_menu(my_menu); + wrefresh(my_menu_win); + + while((c = wgetch(my_menu_win)) != KEY_F(1)) + { switch(c) + { case KEY_DOWN: + menu_driver(my_menu, REQ_DOWN_ITEM); + break; + case KEY_UP: + menu_driver(my_menu, REQ_UP_ITEM); + break; + } + wrefresh(my_menu_win); + } + + /* Unpost and free all the memory taken up */ + unpost_menu(my_menu); + free_menu(my_menu); + for(i = 0; i < n_choices; ++i) + free_item(my_items[i]); + endwin(); +} + +void print_in_middle(WINDOW *win, int starty, int startx, int width, char *string, chtype color) +{ int length, x, y; + float temp; + + if(win == NULL) + win = stdscr; + getyx(win, y, x); + if(startx != 0) + x = startx; + if(starty != 0) + y = starty; + if(width == 0) + width = 80; + + length = strlen(string); + temp = (width - length)/ 2; + x = startx + (int)temp; + wattron(win, color); + mvwprintw(win, y, x, "%s", string); + wattroff(win, color); + refresh(); +}</span></font> +</pre></td> +</tr> +</table> +</div> +<p>This example creates a menu with a title, border, a fancy line +separating title and the items. As you can see, in order to attach +a window to a menu the function set_menu_win() has to be used. Then +we attach the sub window also. This displays the items in the sub +window. You can also set the mark string which gets displayed to +the left of the selected item with set_menu_mark().</p> +</div> +<div class="SECT2"> +<hr> +<h3 class="SECT2"><a name="SCROLLMENUS" id="SCROLLMENUS">17.5. +Scrolling Menus</a></h3> +<p>If the sub window given for a window is not big enough to show +all the items, then the menu will be scrollable. When you are on +the last item in the present list, if you send REQ_DOWN_ITEM, it +gets translated into REQ_SCR_DLINE and the menu scrolls by one +item. You can manually give REQ_SCR_ operations to do scrolling. +Let's see how it can be done.</p> +<div class="EXAMPLE"><a name="MMESC" id="MMESC"></a> +<p><b>Example 20. Scrolling Menus example</b></p> +<table border="0" bgcolor="#E0E0E0" width="100%"> +<tr> +<td> +<pre class="PROGRAMLISTING"> +<font color="#000000"><span class= +"INLINEMEDIAOBJECT">#include <curses.h> +#include <menu.h> + +#define ARRAY_SIZE(a) (sizeof(a) / sizeof(a[0])) +#define CTRLD 4 + +char *choices[] = { + "Choice 1", + "Choice 2", + "Choice 3", + "Choice 4", + "Choice 5", + "Choice 6", + "Choice 7", + "Choice 8", + "Choice 9", + "Choice 10", + "Exit", + (char *)NULL, + }; +void print_in_middle(WINDOW *win, int starty, int startx, int width, char *string, chtype color); + +int main() +{ ITEM **my_items; + int c; + MENU *my_menu; + WINDOW *my_menu_win; + int n_choices, i; + + /* Initialize curses */ + initscr(); + start_color(); + cbreak(); + noecho(); + keypad(stdscr, TRUE); + init_pair(1, COLOR_RED, COLOR_BLACK); + init_pair(2, COLOR_CYAN, COLOR_BLACK); + + /* Create items */ + n_choices = ARRAY_SIZE(choices); + my_items = (ITEM **)calloc(n_choices, sizeof(ITEM *)); + for(i = 0; i < n_choices; ++i) + my_items[i] = new_item(choices[i], choices[i]); + + /* Crate menu */ + my_menu = new_menu((ITEM **)my_items); + + /* Create the window to be associated with the menu */ + my_menu_win = newwin(10, 40, 4, 4); + keypad(my_menu_win, TRUE); + + /* Set main window and sub window */ + set_menu_win(my_menu, my_menu_win); + set_menu_sub(my_menu, derwin(my_menu_win, 6, 38, 3, 1)); + set_menu_format(my_menu, 5, 1); + + /* Set menu mark to the string " * " */ + set_menu_mark(my_menu, " * "); + + /* Print a border around the main window and print a title */ + box(my_menu_win, 0, 0); + print_in_middle(my_menu_win, 1, 0, 40, "My Menu", COLOR_PAIR(1)); + mvwaddch(my_menu_win, 2, 0, ACS_LTEE); + mvwhline(my_menu_win, 2, 1, ACS_HLINE, 38); + mvwaddch(my_menu_win, 2, 39, ACS_RTEE); + + /* Post the menu */ + post_menu(my_menu); + wrefresh(my_menu_win); + + attron(COLOR_PAIR(2)); + mvprintw(LINES - 2, 0, "Use PageUp and PageDown to scoll down or up a page of items"); + mvprintw(LINES - 1, 0, "Arrow Keys to navigate (F1 to Exit)"); + attroff(COLOR_PAIR(2)); + refresh(); + + while((c = wgetch(my_menu_win)) != KEY_F(1)) + { switch(c) + { case KEY_DOWN: + menu_driver(my_menu, REQ_DOWN_ITEM); + break; + case KEY_UP: + menu_driver(my_menu, REQ_UP_ITEM); + break; + case KEY_NPAGE: + menu_driver(my_menu, REQ_SCR_DPAGE); + break; + case KEY_PPAGE: + menu_driver(my_menu, REQ_SCR_UPAGE); + break; + } + wrefresh(my_menu_win); + } + + /* Unpost and free all the memory taken up */ + unpost_menu(my_menu); + free_menu(my_menu); + for(i = 0; i < n_choices; ++i) + free_item(my_items[i]); + endwin(); +} + +void print_in_middle(WINDOW *win, int starty, int startx, int width, char *string, chtype color) +{ int length, x, y; + float temp; + + if(win == NULL) + win = stdscr; + getyx(win, y, x); + if(startx != 0) + x = startx; + if(starty != 0) + y = starty; + if(width == 0) + width = 80; + + length = strlen(string); + temp = (width - length)/ 2; + x = startx + (int)temp; + wattron(win, color); + mvwprintw(win, y, x, "%s", string); + wattroff(win, color); + refresh(); +}</span></font> +</pre></td> +</tr> +</table> +</div> +<p>This program is self-explanatory. In this example the number of +choices has been increased to ten, which is larger than our sub +window size which can hold 6 items. This message has to be +explicitly conveyed to the menu system with the function +set_menu_format(). In here we specify the number of rows and +columns we want to be displayed for a single page. We can specify +any number of items to be shown, in the rows variables, if it is +less than the height of the sub window. If the key pressed by the +user is a PAGE UP or PAGE DOWN, the menu is scrolled a page due to +the requests (REQ_SCR_DPAGE and REQ_SCR_UPAGE) given to +menu_driver().</p> +</div> +<div class="SECT2"> +<hr> +<h3 class="SECT2"><a name="MULTICOLUMN" id="MULTICOLUMN">17.6. +Multi Columnar Menus</a></h3> +<p>In the above example you have seen how to use the function +set_menu_format(). I didn't mention what the cols variable (third +parameter) does. Well, If your sub window is wide enough, you can +opt to display more than one item per row. This can be specified in +the cols variable. To make things simpler, the following example +doesn't show descriptions for the items.</p> +<div class="EXAMPLE"><a name="MMEMUCO" id="MMEMUCO"></a> +<p><b>Example 21. Milt Columnar Menus Example</b></p> +<table border="0" bgcolor="#E0E0E0" width="100%"> +<tr> +<td> +<pre class="PROGRAMLISTING"> +<font color="#000000"><span class= +"INLINEMEDIAOBJECT">#include <curses.h> +#include <menu.h> + +#define ARRAY_SIZE(a) (sizeof(a) / sizeof(a[0])) +#define CTRLD 4 + +char *choices[] = { + "Choice 1", "Choice 2", "Choice 3", "Choice 4", "Choice 5", + "Choice 6", "Choice 7", "Choice 8", "Choice 9", "Choice 10", + "Choice 11", "Choice 12", "Choice 13", "Choice 14", "Choice 15", + "Choice 16", "Choice 17", "Choice 18", "Choice 19", "Choice 20", + "Exit", + (char *)NULL, + }; + +int main() +{ ITEM **my_items; + int c; + MENU *my_menu; + WINDOW *my_menu_win; + int n_choices, i; + + /* Initialize curses */ + initscr(); + start_color(); + cbreak(); + noecho(); + keypad(stdscr, TRUE); + init_pair(1, COLOR_RED, COLOR_BLACK); + init_pair(2, COLOR_CYAN, COLOR_BLACK); + + /* Create items */ + n_choices = ARRAY_SIZE(choices); + my_items = (ITEM **)calloc(n_choices, sizeof(ITEM *)); + for(i = 0; i < n_choices; ++i) + my_items[i] = new_item(choices[i], choices[i]); + + /* Crate menu */ + my_menu = new_menu((ITEM **)my_items); + + /* Set menu option not to show the description */ + menu_opts_off(my_menu, O_SHOWDESC); + + /* Create the window to be associated with the menu */ + my_menu_win = newwin(10, 70, 4, 4); + keypad(my_menu_win, TRUE); + + /* Set main window and sub window */ + set_menu_win(my_menu, my_menu_win); + set_menu_sub(my_menu, derwin(my_menu_win, 6, 68, 3, 1)); + set_menu_format(my_menu, 5, 3); + set_menu_mark(my_menu, " * "); + + /* Print a border around the main window and print a title */ + box(my_menu_win, 0, 0); + + attron(COLOR_PAIR(2)); + mvprintw(LINES - 3, 0, "Use PageUp and PageDown to scroll"); + mvprintw(LINES - 2, 0, "Use Arrow Keys to navigate (F1 to Exit)"); + attroff(COLOR_PAIR(2)); + refresh(); + + /* Post the menu */ + post_menu(my_menu); + wrefresh(my_menu_win); + + while((c = wgetch(my_menu_win)) != KEY_F(1)) + { switch(c) + { case KEY_DOWN: + menu_driver(my_menu, REQ_DOWN_ITEM); + break; + case KEY_UP: + menu_driver(my_menu, REQ_UP_ITEM); + break; + case KEY_LEFT: + menu_driver(my_menu, REQ_LEFT_ITEM); + break; + case KEY_RIGHT: + menu_driver(my_menu, REQ_RIGHT_ITEM); + break; + case KEY_NPAGE: + menu_driver(my_menu, REQ_SCR_DPAGE); + break; + case KEY_PPAGE: + menu_driver(my_menu, REQ_SCR_UPAGE); + break; + } + wrefresh(my_menu_win); + } + + /* Unpost and free all the memory taken up */ + unpost_menu(my_menu); + free_menu(my_menu); + for(i = 0; i < n_choices; ++i) + free_item(my_items[i]); + endwin(); +}</span></font> +</pre></td> +</tr> +</table> +</div> +<p>Watch the function call to set_menu_format(). It specifies the +number of columns to be 3, thus displaying 3 items per row. We have +also switched off the showing descriptions with the function +menu_opts_off(). There are couple of functions set_menu_opts(), +menu_opts_on() and menu_opts() which can be used to manipulate menu +options. The following menu options can be specified.</p> +<table border="0" bgcolor="#E0E0E0" width="100%"> +<tr> +<td> +<pre class="PROGRAMLISTING"> +<font color="#000000"> O_ONEVALUE + Only one item can be selected for this menu. + + O_SHOWDESC + Display the item descriptions when the menu is + posted. + + O_ROWMAJOR + Display the menu in row-major order. + + O_IGNORECASE + Ignore the case when pattern-matching. + + O_SHOWMATCH + Move the cursor to within the item name while pat­ + tern-matching. + + O_NONCYCLIC + Don't wrap around next-item and previous-item, + requests to the other end of the menu.</font> +</pre></td> +</tr> +</table> +<p>All options are on by default. You can switch specific +attributes on or off with menu_opts_on() and menu_opts_off() +functions. You can also use set_menu_opts() to directly specify the +options. The argument to this function should be a OR ed value of +some of those above constants. The function menu_opts() can be used +to find out a menu's present options.</p> +</div> +<div class="SECT2"> +<hr> +<h3 class="SECT2"><a name="MULTIVALUEMENUS" id= +"MULTIVALUEMENUS">17.7. Multi Valued Menus</a></h3> +<p>You might be wondering what if you switch off the option +O_ONEVALUE. Then the menu becomes multi-valued. That means you can +select more than one item. This brings us to the request +REQ_TOGGLE_ITEM. Let's see it in action.</p> +<div class="EXAMPLE"><a name="MMETO" id="MMETO"></a> +<p><b>Example 22. Multi Valued Menus example</b></p> +<table border="0" bgcolor="#E0E0E0" width="100%"> +<tr> +<td> +<pre class="PROGRAMLISTING"> +<font color="#000000"><span class= +"INLINEMEDIAOBJECT">#include <curses.h> +#include <menu.h> + +#define ARRAY_SIZE(a) (sizeof(a) / sizeof(a[0])) +#define CTRLD 4 + +char *choices[] = { + "Choice 1", + "Choice 2", + "Choice 3", + "Choice 4", + "Choice 5", + "Choice 6", + "Choice 7", + "Exit", + }; + +int main() +{ ITEM **my_items; + int c; + MENU *my_menu; + int n_choices, i; + ITEM *cur_item; + + /* Initialize curses */ + initscr(); + cbreak(); + noecho(); + keypad(stdscr, TRUE); + + /* Initialize items */ + n_choices = ARRAY_SIZE(choices); + my_items = (ITEM **)calloc(n_choices + 1, sizeof(ITEM *)); + for(i = 0; i < n_choices; ++i) + my_items[i] = new_item(choices[i], choices[i]); + my_items[n_choices] = (ITEM *)NULL; + + my_menu = new_menu((ITEM **)my_items); + + /* Make the menu multi valued */ + menu_opts_off(my_menu, O_ONEVALUE); + + mvprintw(LINES - 3, 0, "Use <SPACE> to select or unselect an item."); + mvprintw(LINES - 2, 0, "<ENTER> to see presently selected items(F1 to Exit)"); + post_menu(my_menu); + refresh(); + + while((c = getch()) != KEY_F(1)) + { switch(c) + { case KEY_DOWN: + menu_driver(my_menu, REQ_DOWN_ITEM); + break; + case KEY_UP: + menu_driver(my_menu, REQ_UP_ITEM); + break; + case ' ': + menu_driver(my_menu, REQ_TOGGLE_ITEM); + break; + case 10: /* Enter */ + { char temp[200]; + ITEM **items; + + items = menu_items(my_menu); + temp[0] = '\0'; + for(i = 0; i < item_count(my_menu); ++i) + if(item_value(items[i]) == TRUE) + { strcat(temp, item_name(items[i])); + strcat(temp, " "); + } + move(20, 0); + clrtoeol(); + mvprintw(20, 0, temp); + refresh(); + } + break; + } + } + + free_item(my_items[0]); + free_item(my_items[1]); + free_menu(my_menu); + endwin(); +} + </span></font> +</pre></td> +</tr> +</table> +</div> +<p>Whew, A lot of new functions. Let's take them one after another. +Firstly, the REQ_TOGGLE_ITEM. In a multi-valued menu, the user +should be allowed to select or un select more than one item. The +request REQ_TOGGLE_ITEM toggles the present selection. In this case +when space is pressed REQ_TOGGLE_ITEM request is sent to +menu_driver to achieve the result.</p> +<p>Now when the user presses <ENTER> we show the items he +presently selected. First we find out the items associated with the +menu using the function menu_items(). Then we loop through the +items to find out if the item is selected or not. The function +item_value() returns TRUE if an item is selected. The function +item_count() returns the number of items in the menu. The item name +can be found with item_name(). You can also find the description +associated with an item using item_description().</p> +</div> +<div class="SECT2"> +<hr> +<h3 class="SECT2"><a name="MENUOPT" id="MENUOPT">17.8. Menu +Options</a></h3> +<p>Well, by this time you must be itching for some difference in +your menu, with lots of functionality. I know. You want Colors !!!. +You want to create nice menus similar to those text mode <a href= +"http://www.jersey.net/~debinjoe/games/" target="_top">dos +games</a>. The functions set_menu_fore() and set_menu_back() can be +used to change the attribute of the selected item and unselected +item. The names are misleading. They don't change menu's foreground +or background which would have been useless.</p> +<p>The function set_menu_grey() can be used to set the display +attribute for the non-selectable items in the menu. This brings us +to the interesting option for an item the one and only +O_SELECTABLE. We can turn it off by the function item_opts_off() +and after that that item is not selectable. It's like a grayed item +in those fancy windows menus. Let's put these concepts in practice +with this example</p> +<div class="EXAMPLE"><a name="MMEAT" id="MMEAT"></a> +<p><b>Example 23. Menu Options example</b></p> +<table border="0" bgcolor="#E0E0E0" width="100%"> +<tr> +<td> +<pre class="PROGRAMLISTING"> +<font color="#000000"><span class= +"INLINEMEDIAOBJECT">#include <menu.h> + +#define ARRAY_SIZE(a) (sizeof(a) / sizeof(a[0])) +#define CTRLD 4 + +char *choices[] = { + "Choice 1", + "Choice 2", + "Choice 3", + "Choice 4", + "Choice 5", + "Choice 6", + "Choice 7", + "Exit", + }; + +int main() +{ ITEM **my_items; + int c; + MENU *my_menu; + int n_choices, i; + ITEM *cur_item; + + /* Initialize curses */ + initscr(); + start_color(); + cbreak(); + noecho(); + keypad(stdscr, TRUE); + init_pair(1, COLOR_RED, COLOR_BLACK); + init_pair(2, COLOR_GREEN, COLOR_BLACK); + init_pair(3, COLOR_MAGENTA, COLOR_BLACK); + + /* Initialize items */ + n_choices = ARRAY_SIZE(choices); + my_items = (ITEM **)calloc(n_choices + 1, sizeof(ITEM *)); + for(i = 0; i < n_choices; ++i) + my_items[i] = new_item(choices[i], choices[i]); + my_items[n_choices] = (ITEM *)NULL; + item_opts_off(my_items[3], O_SELECTABLE); + item_opts_off(my_items[6], O_SELECTABLE); + + /* Create menu */ + my_menu = new_menu((ITEM **)my_items); + + /* Set fore ground and back ground of the menu */ + set_menu_fore(my_menu, COLOR_PAIR(1) | A_REVERSE); + set_menu_back(my_menu, COLOR_PAIR(2)); + set_menu_grey(my_menu, COLOR_PAIR(3)); + + /* Post the menu */ + mvprintw(LINES - 3, 0, "Press <ENTER> to see the option selected"); + mvprintw(LINES - 2, 0, "Up and Down arrow keys to naviage (F1 to Exit)"); + post_menu(my_menu); + refresh(); + + while((c = getch()) != KEY_F(1)) + { switch(c) + { case KEY_DOWN: + menu_driver(my_menu, REQ_DOWN_ITEM); + break; + case KEY_UP: + menu_driver(my_menu, REQ_UP_ITEM); + break; + case 10: /* Enter */ + move(20, 0); + clrtoeol(); + mvprintw(20, 0, "Item selected is : %s", + item_name(current_item(my_menu))); + pos_menu_cursor(my_menu); + break; + } + } + unpost_menu(my_menu); + for(i = 0; i < n_choices; ++i) + free_item(my_items[i]); + free_menu(my_menu); + endwin(); +} + </span></font> +</pre></td> +</tr> +</table> +</div> +</div> +<div class="SECT2"> +<hr> +<h3 class="SECT2"><a name="MENUUSERPTR" id="MENUUSERPTR">17.9. The +useful User Pointer</a></h3> +<p>We can associate a user pointer with each item in the menu. It +works the same way as user pointer in panels. It's not touched by +menu system. You can store any thing you like in that. I usually +use it to store the function to be executed when the menu option is +chosen (It's selected and may be the user pressed +<ENTER>);</p> +<div class="EXAMPLE"><a name="MMEUS" id="MMEUS"></a> +<p><b>Example 24. Menu User Pointer Usage</b></p> +<table border="0" bgcolor="#E0E0E0" width="100%"> +<tr> +<td> +<pre class="PROGRAMLISTING"> +<font color="#000000"><span class= +"INLINEMEDIAOBJECT">#include <curses.h> +#include <menu.h> + +#define ARRAY_SIZE(a) (sizeof(a) / sizeof(a[0])) +#define CTRLD 4 + +char *choices[] = { + "Choice 1", + "Choice 2", + "Choice 3", + "Choice 4", + "Choice 5", + "Choice 6", + "Choice 7", + "Exit", + }; +void func(char *name); + +int main() +{ ITEM **my_items; + int c; + MENU *my_menu; + int n_choices, i; + ITEM *cur_item; + + /* Initialize curses */ + initscr(); + start_color(); + cbreak(); + noecho(); + keypad(stdscr, TRUE); + init_pair(1, COLOR_RED, COLOR_BLACK); + init_pair(2, COLOR_GREEN, COLOR_BLACK); + init_pair(3, COLOR_MAGENTA, COLOR_BLACK); + + /* Initialize items */ + n_choices = ARRAY_SIZE(choices); + my_items = (ITEM **)calloc(n_choices + 1, sizeof(ITEM *)); + for(i = 0; i < n_choices; ++i) + { my_items[i] = new_item(choices[i], choices[i]); + /* Set the user pointer */ + set_item_userptr(my_items[i], func); + } + my_items[n_choices] = (ITEM *)NULL; + + /* Create menu */ + my_menu = new_menu((ITEM **)my_items); + + /* Post the menu */ + mvprintw(LINES - 3, 0, "Press <ENTER> to see the option selected"); + mvprintw(LINES - 2, 0, "Up and Down arrow keys to naviage (F1 to Exit)"); + post_menu(my_menu); + refresh(); + + while((c = getch()) != KEY_F(1)) + { switch(c) + { case KEY_DOWN: + menu_driver(my_menu, REQ_DOWN_ITEM); + break; + case KEY_UP: + menu_driver(my_menu, REQ_UP_ITEM); + break; + case 10: /* Enter */ + { ITEM *cur; + void (*p)(char *); + + cur = current_item(my_menu); + p = item_userptr(cur); + p((char *)item_name(cur)); + pos_menu_cursor(my_menu); + break; + } + break; + } + } + unpost_menu(my_menu); + for(i = 0; i < n_choices; ++i) + free_item(my_items[i]); + free_menu(my_menu); + endwin(); +} + +void func(char *name) +{ move(20, 0); + clrtoeol(); + mvprintw(20, 0, "Item selected is : %s", name); +} </span></font> +</pre></td> +</tr> +</table> +</div> +</div> +</div> +<div class="SECT1"> +<hr> +<h2 class="SECT1"><a name="FORMS" id="FORMS">18. Forms +Library</a></h2> +<p>Well. If you have seen those forms on web pages which take input +from users and do various kinds of things, you might be wondering +how would any one create such forms in text mode display. It's +quite difficult to write those nifty forms in plain ncurses. Forms +library tries to provide a basic frame work to build and maintain +forms with ease. It has lot of features(functions) which manage +validation, dynamic expansion of fields etc.. Let's see it in full +flow.</p> +<p>A form is a collection of fields; each field can be either a +label(static text) or a data-entry location. The forms also library +provides functions to divide forms into multiple pages.</p> +<div class="SECT2"> +<hr> +<h3 class="SECT2"><a name="FORMBASICS" id="FORMBASICS">18.1. The +Basics</a></h3> +<p>Forms are created in much the same way as menus. First the +fields related to the form are created with new_field(). You can +set options for the fields, so that they can be displayed with some +fancy attributes, validated before the field looses focus etc.. +Then the fields are attached to form. After this, the form can be +posted to display and is ready to receive inputs. On the similar +lines to menu_driver(), the form is manipulated with form_driver(). +We can send requests to form_driver to move focus to a certain +field, move cursor to end of the field etc.. After the user enters +values in the fields and validation done, form can be unposted and +memory allocated can be freed.</p> +<p>The general flow of control of a forms program looks like +this.</p> +<ol type="1"> +<li> +<p>Initialize curses</p> +</li> +<li> +<p>Create fields using new_field(). You can specify the height and +width of the field, and its position on the form.</p> +</li> +<li> +<p>Create the forms with new_form() by specifying the fields to be +attached with.</p> +</li> +<li> +<p>Post the form with form_post() and refresh the screen.</p> +</li> +<li> +<p>Process the user requests with a loop and do necessary updates +to form with form_driver.</p> +</li> +<li> +<p>Unpost the menu with form_unpost()</p> +</li> +<li> +<p>Free the memory allocated to menu by free_form()</p> +</li> +<li> +<p>Free the memory allocated to the items with free_field()</p> +</li> +<li> +<p>End curses</p> +</li> +</ol> +<p>As you can see, working with forms library is much similar to +handling menu library. The following examples will explore various +aspects of form processing. Let's start the journey with a simple +example. first.</p> +</div> +<div class="SECT2"> +<hr> +<h3 class="SECT2"><a name="COMPILEFORMS" id="COMPILEFORMS">18.2. +Compiling With the Forms Library</a></h3> +<p>To use forms library functions, you have to include form.h and +to link the program with forms library the flag -lform should be +added along with -lncurses in that order.</p> +<table border="0" bgcolor="#E0E0E0" width="100%"> +<tr> +<td> +<pre class="PROGRAMLISTING"> +<font color="#000000"> #include <form.h> + . + . + . + + compile and link: gcc <program file> -lform -lncurses</font> +</pre></td> +</tr> +</table> +<div class="EXAMPLE"><a name="FFOSI" id="FFOSI"></a> +<p><b>Example 25. Forms Basics</b></p> +<table border="0" bgcolor="#E0E0E0" width="100%"> +<tr> +<td> +<pre class="PROGRAMLISTING"> +<font color="#000000"><span class= +"INLINEMEDIAOBJECT">#include <form.h> + +int main() +{ FIELD *field[3]; + FORM *my_form; + int ch; + + /* Initialize curses */ + initscr(); + cbreak(); + noecho(); + keypad(stdscr, TRUE); + + /* Initialize the fields */ + field[0] = new_field(1, 10, 4, 18, 0, 0); + field[1] = new_field(1, 10, 6, 18, 0, 0); + field[2] = NULL; + + /* Set field options */ + set_field_back(field[0], A_UNDERLINE); /* Print a line for the option */ + field_opts_off(field[0], O_AUTOSKIP); /* Don't go to next field when this */ + /* Field is filled up */ + set_field_back(field[1], A_UNDERLINE); + field_opts_off(field[1], O_AUTOSKIP); + + /* Create the form and post it */ + my_form = new_form(field); + post_form(my_form); + refresh(); + + mvprintw(4, 10, "Value 1:"); + mvprintw(6, 10, "Value 2:"); + refresh(); + + /* Loop through to get user requests */ + while((ch = getch()) != KEY_F(1)) + { switch(ch) + { case KEY_DOWN: + /* Go to next field */ + form_driver(my_form, REQ_NEXT_FIELD); + /* Go to the end of the present buffer */ + /* Leaves nicely at the last character */ + form_driver(my_form, REQ_END_LINE); + break; + case KEY_UP: + /* Go to previous field */ + form_driver(my_form, REQ_PREV_FIELD); + form_driver(my_form, REQ_END_LINE); + break; + default: + /* If this is a normal character, it gets */ + /* Printed */ + form_driver(my_form, ch); + break; + } + } + + /* Un post form and free the memory */ + unpost_form(my_form); + free_form(my_form); + free_field(field[0]); + free_field(field[1]); + + endwin(); + return 0; +}</span></font> +</pre></td> +</tr> +</table> +</div> +<p>Above example is pretty straight forward. It creates two fields +with <var class="LITERAL">new_field()</var>. new_field() takes +height, width, starty, startx, number of offscreen rows and number +of additional working buffers. The fifth argument number of +offscreen rows specifies how much of the field to be shown. If it +is zero, the entire field is always displayed otherwise the form +will be scrollable when the user accesses not displayed parts of +the field. The forms library allocates one buffer per field to +store the data user enters. Using the last parameter to new_field() +we can specify it to allocate some additional buffers. These can be +used for any purpose you like.</p> +<p>After creating the fields, back ground attribute of both of them +is set to an underscore with set_field_back(). The AUTOSKIP option +is turned off using field_opts_off(). If this option is turned on, +focus will move to the next field in the form once the active field +is filled up completely.</p> +<p>After attaching the fields to the form, it is posted. Here on, +user inputs are processed in the while loop, by making +corresponding requests to form_driver. The details of all the +requests to the form_driver() are explained later.</p> +</div> +<div class="SECT2"> +<hr> +<h3 class="SECT2"><a name="PLAYFIELDS" id="PLAYFIELDS">18.3. +Playing with Fields</a></h3> +<p>Each form field is associated with a lot of attributes. They can +be manipulated to get the required effect and to have fun !!!. So +why wait?</p> +<div class="SECT3"> +<hr> +<h4 class="SECT3"><a name="FETCHINFO" id="FETCHINFO">18.3.1. +Fetching Size and Location of Field</a></h4> +<p>The parameters we have given at the time of creation of a field +can be retrieved with field_info(). It returns height, width, +starty, startx, number of offscreen rows, and number of additional +buffers into the parameters given to it. It is a sort of inverse of +new_field().</p> +<table border="0" bgcolor="#E0E0E0" width="100%"> +<tr> +<td> +<pre class="PROGRAMLISTING"> +<font color= +"#000000">int field_info( FIELD *field, /* field from which to fetch */ + int *height, *int width, /* field size */ + int *top, int *left, /* upper left corner */ + int *offscreen, /* number of offscreen rows */ + int *nbuf); /* number of working buffers */</font> +</pre></td> +</tr> +</table> +</div> +<div class="SECT3"> +<hr> +<h4 class="SECT3"><a name="MOVEFIELD" id="MOVEFIELD">18.3.2. Moving +the field</a></h4> +<p>The location of the field can be moved to a different position +with move_field().</p> +<table border="0" bgcolor="#E0E0E0" width="100%"> +<tr> +<td> +<pre class="PROGRAMLISTING"> +<font color= +"#000000">int move_field( FIELD *field, /* field to alter */ + int top, int left); /* new upper-left corner */</font> +</pre></td> +</tr> +</table> +<p>As usual, the changed position can be queried with +field_infor().</p> +</div> +<div class="SECT3"> +<hr> +<h4 class="SECT3"><a name="JUSTIFYFIELD" id="JUSTIFYFIELD">18.3.3. +Field Justification</a></h4> +<p>The justification to be done for the field can be fixed using +the function set_field_just().</p> +<table border="0" bgcolor="#E0E0E0" width="100%"> +<tr> +<td> +<pre class="PROGRAMLISTING"> +<font color= +"#000000"> int set_field_just(FIELD *field, /* field to alter */ + int justmode); /* mode to set */ + int field_just(FIELD *field); /* fetch justify mode of field */</font> +</pre></td> +</tr> +</table> +<p>The justification mode valued accepted and returned by these +functions are NO_JUSTIFICATION, JUSTIFY_RIGHT, JUSTIFY_LEFT, or +JUSTIFY_CENTER.</p> +</div> +<div class="SECT3"> +<hr> +<h4 class="SECT3"><a name="FIELDDISPATTRIB" id= +"FIELDDISPATTRIB">18.3.4. Field Display Attributes</a></h4> +<p>As you have seen, in the above example, display attribute for +the fields can be set with set_field_fore() and setfield_back(). +These functions set foreground and background attribute of the +fields. You can also specify a pad character which will be filled +in the unfilled portion of the field. The pad character is set with +a call to set_field_pad(). Default pad value is a space. The +functions field_fore(), field_back, field_pad() can be used to +query the present foreground, background attributes and pad +character for the field. The following list gives the usage of +functions.</p> +<table border="0" bgcolor="#E0E0E0" width="100%"> +<tr> +<td> +<pre class="PROGRAMLISTING"> +<font color= +"#000000"> int set_field_fore(FIELD *field, /* field to alter */ + chtype attr); /* attribute to set */ + +chtype field_fore(FIELD *field); /* field to query */ + /* returns foreground attribute */ + +int set_field_back(FIELD *field, /* field to alter */ + chtype attr); /* attribute to set */ + +chtype field_back(FIELD *field); /* field to query */ + /* returns background attribute */ + +int set_field_pad(FIELD *field, /* field to alter */ + int pad); /* pad character to set */ + +chtype field_pad(FIELD *field); /* field to query */ + /* returns present pad character */ </font> +</pre></td> +</tr> +</table> +<p>Though above functions seem quite simple, using colors with +set_field_fore() may be frustrating in the beginning. Let me first +explain about foreground and background attributes of a field. The +foreground attribute is associated with the character. That means a +character in the field is printed with the attribute you have set +with set_field_fore(). Background attribute is the attribute used +to fill background of field, whether any character is there or not. +So what about colors? Since colors are always defined in pairs, +what is the right way to display colored fields? Here's an example +clarifying color attributes.</p> +<div class="EXAMPLE"><a name="FFOAT" id="FFOAT"></a> +<p><b>Example 26. Form Attributes example</b></p> +<table border="0" bgcolor="#E0E0E0" width="100%"> +<tr> +<td> +<pre class="PROGRAMLISTING"> +<font color="#000000"><span class= +"INLINEMEDIAOBJECT">#include <form.h> + +int main() +{ FIELD *field[3]; + FORM *my_form; + int ch; + + /* Initialize curses */ + initscr(); + start_color(); + cbreak(); + noecho(); + keypad(stdscr, TRUE); + + /* Initialize few color pairs */ + init_pair(1, COLOR_WHITE, COLOR_BLUE); + init_pair(2, COLOR_WHITE, COLOR_BLUE); + + /* Initialize the fields */ + field[0] = new_field(1, 10, 4, 18, 0, 0); + field[1] = new_field(1, 10, 6, 18, 0, 0); + field[2] = NULL; + + /* Set field options */ + set_field_fore(field[0], COLOR_PAIR(1));/* Put the field with blue background */ + set_field_back(field[0], COLOR_PAIR(2));/* and white foreground (characters */ + /* are printed in white */ + field_opts_off(field[0], O_AUTOSKIP); /* Don't go to next field when this */ + /* Field is filled up */ + set_field_back(field[1], A_UNDERLINE); + field_opts_off(field[1], O_AUTOSKIP); + + /* Create the form and post it */ + my_form = new_form(field); + post_form(my_form); + refresh(); + + set_current_field(my_form, field[0]); /* Set focus to the colored field */ + mvprintw(4, 10, "Value 1:"); + mvprintw(6, 10, "Value 2:"); + mvprintw(LINES - 2, 0, "Use UP, DOWN arrow keys to switch between fields"); + refresh(); + + /* Loop through to get user requests */ + while((ch = getch()) != KEY_F(1)) + { switch(ch) + { case KEY_DOWN: + /* Go to next field */ + form_driver(my_form, REQ_NEXT_FIELD); + /* Go to the end of the present buffer */ + /* Leaves nicely at the last character */ + form_driver(my_form, REQ_END_LINE); + break; + case KEY_UP: + /* Go to previous field */ + form_driver(my_form, REQ_PREV_FIELD); + form_driver(my_form, REQ_END_LINE); + break; + default: + /* If this is a normal character, it gets */ + /* Printed */ + form_driver(my_form, ch); + break; + } + } + + /* Un post form and free the memory */ + unpost_form(my_form); + free_form(my_form); + free_field(field[0]); + free_field(field[1]); + + endwin(); + return 0; +}</span></font> +</pre></td> +</tr> +</table> +</div> +<p>Play with the color pairs and try to understand the foreground +and background attributes. In my programs using color attributes, I +usually set only the background with set_field_back(). Curses +simply doesn't allow defining individual color attributes.</p> +</div> +<div class="SECT3"> +<hr> +<h4 class="SECT3"><a name="FIELDOPTIONBITS" id= +"FIELDOPTIONBITS">18.3.5. Field Option Bits</a></h4> +<p>There is also a large collection of field option bits you can +set to control various aspects of forms processing. You can +manipulate them with these functions:</p> +<table border="0" bgcolor="#E0E0E0" width="100%"> +<tr> +<td> +<pre class="PROGRAMLISTING"> +<font color= +"#000000">int set_field_opts(FIELD *field, /* field to alter */ + int attr); /* attribute to set */ + +int field_opts_on(FIELD *field, /* field to alter */ + int attr); /* attributes to turn on */ + +int field_opts_off(FIELD *field, /* field to alter */ + int attr); /* attributes to turn off */ + +int field_opts(FIELD *field); /* field to query */ </font> +</pre></td> +</tr> +</table> +<p>The function set_field_opts() can be used to directly set +attributes of a field or you can choose to switch a few attributes +on and off with field_opts_on() and field_opts_off() selectively. +Anytime you can query the attributes of a field with field_opts(). +The following is the list of available options. By default, all +options are on.</p> +<div class="VARIABLELIST"> +<dl> +<dt>O_VISIBLE</dt> +<dd> +<p>Controls whether the field is visible on the screen. Can be used +during form processing to hide or pop up fields depending on the +value of parent fields.</p> +</dd> +<dt>O_ACTIVE</dt> +<dd> +<p>Controls whether the field is active during forms processing +(i.e. visited by form navigation keys). Can be used to make labels +or derived fields with buffer values alterable by the forms +application, not the user.</p> +</dd> +<dt>O_PUBLIC</dt> +<dd> +<p>Controls whether data is displayed during field entry. If this +option is turned off on a field, the library will accept and edit +data in that field, but it will not be displayed and the visible +field cursor will not move. You can turn off the O_PUBLIC bit to +define password fields.</p> +</dd> +<dt>O_EDIT</dt> +<dd> +<p>Controls whether the field's data can be modified. When this +option is off, all editing requests except <var class= +"LITERAL">REQ_PREV_CHOICE</var> and <var class= +"LITERAL">REQ_NEXT_CHOICE</var>will fail. Such read-only fields may +be useful for help messages.</p> +</dd> +<dt>O_WRAP</dt> +<dd> +<p>Controls word-wrapping in multi-line fields. Normally, when any +character of a (blank-separated) word reaches the end of the +current line, the entire word is wrapped to the next line (assuming +there is one). When this option is off, the word will be split +across the line break.</p> +</dd> +<dt>O_BLANK</dt> +<dd> +<p>Controls field blanking. When this option is on, entering a +character at the first field position erases the entire field +(except for the just-entered character).</p> +</dd> +<dt>O_AUTOSKIP</dt> +<dd> +<p>Controls automatic skip to next field when this one fills. +Normally, when the forms user tries to type more data into a field +than will fit, the editing location jumps to next field. When this +option is off, the user's cursor will hang at the end of the field. +This option is ignored in dynamic fields that have not reached +their size limit.</p> +</dd> +<dt>O_NULLOK</dt> +<dd> +<p>Controls whether validation is applied to blank fields. +Normally, it is not; the user can leave a field blank without +invoking the usual validation check on exit. If this option is off +on a field, exit from it will invoke a validation check.</p> +</dd> +<dt>O_PASSOK</dt> +<dd> +<p>Controls whether validation occurs on every exit, or only after +the field is modified. Normally the latter is true. Setting +O_PASSOK may be useful if your field's validation function may +change during forms processing.</p> +</dd> +<dt>O_STATIC</dt> +<dd> +<p>Controls whether the field is fixed to its initial dimensions. +If you turn this off, the field becomes dynamic and will stretch to +fit entered data.</p> +</dd> +</dl> +</div> +<p>A field's options cannot be changed while the field is currently +selected. However, options may be changed on posted fields that are +not current.</p> +<p>The option values are bit-masks and can be composed with +logical-or in the obvious way. You have seen the usage of switching +off O_AUTOSKIP option. The following example clarifies usage of +some more options. Other options are explained where +appropriate.</p> +<div class="EXAMPLE"><a name="FFOOP" id="FFOOP"></a> +<p><b>Example 27. Field Options Usage example</b></p> +<table border="0" bgcolor="#E0E0E0" width="100%"> +<tr> +<td> +<pre class="PROGRAMLISTING"> +<font color="#000000"><span class= +"INLINEMEDIAOBJECT">#include <form.h> + +#define STARTX 15 +#define STARTY 4 +#define WIDTH 25 + +#define N_FIELDS 3 + +int main() +{ FIELD *field[N_FIELDS]; + FORM *my_form; + int ch, i; + + /* Initialize curses */ + initscr(); + cbreak(); + noecho(); + keypad(stdscr, TRUE); + + /* Initialize the fields */ + for(i = 0; i < N_FIELDS - 1; ++i) + field[i] = new_field(1, WIDTH, STARTY + i * 2, STARTX, 0, 0); + field[N_FIELDS - 1] = NULL; + + /* Set field options */ + set_field_back(field[1], A_UNDERLINE); /* Print a line for the option */ + + field_opts_off(field[0], O_ACTIVE); /* This field is a static label */ + field_opts_off(field[1], O_PUBLIC); /* This filed is like a password field*/ + field_opts_off(field[1], O_AUTOSKIP); /* To avoid entering the same field */ + /* after last character is entered */ + + /* Create the form and post it */ + my_form = new_form(field); + post_form(my_form); + refresh(); + + set_field_just(field[0], JUSTIFY_CENTER); /* Center Justification */ + set_field_buffer(field[0], 0, "This is a static Field"); + /* Initialize the field */ + mvprintw(STARTY, STARTX - 10, "Field 1:"); + mvprintw(STARTY + 2, STARTX - 10, "Field 2:"); + refresh(); + + /* Loop through to get user requests */ + while((ch = getch()) != KEY_F(1)) + { switch(ch) + { case KEY_DOWN: + /* Go to next field */ + form_driver(my_form, REQ_NEXT_FIELD); + /* Go to the end of the present buffer */ + /* Leaves nicely at the last character */ + form_driver(my_form, REQ_END_LINE); + break; + case KEY_UP: + /* Go to previous field */ + form_driver(my_form, REQ_PREV_FIELD); + form_driver(my_form, REQ_END_LINE); + break; + default: + /* If this is a normal character, it gets */ + /* Printed */ + form_driver(my_form, ch); + break; + } + } + + /* Un post form and free the memory */ + unpost_form(my_form); + free_form(my_form); + free_field(field[0]); + free_field(field[1]); + + endwin(); + return 0; +}</span></font> +</pre></td> +</tr> +</table> +</div> +<p>This example, though useless, shows the usage of options. If +used properly, they can present information very effectively in a +form. The second field being not O_PUBLIC, does not show the +characters you are typing.</p> +</div> +<div class="SECT3"> +<hr> +<h4 class="SECT3"><a name="FIELDSTATUS" id="FIELDSTATUS">18.3.6. +Field Status</a></h4> +<p>The field status specifies whether the field has got edited or +not. It is initially set to FALSE and when user enters something +and the data buffer gets modified it becomes TRUE. So a field's +status can be queried to find out whether it has been modified or +not. The following functions can assist in those operations.</p> +<table border="0" bgcolor="#E0E0E0" width="100%"> +<tr> +<td> +<pre class="PROGRAMLISTING"> +<font color= +"#000000">int set_field_status(FIELD *field, /* field to alter */ + int status); /* status to set */ + +int field_status(FIELD *field); /* fetch status of field */</font> +</pre></td> +</tr> +</table> +<p>It's better to check the field's status only after after leaving +the field, as data buffer might not have been updated yet as the +validation is still due. To guarantee that right status is +returned, call field_status() either (1) in the field's exit +validation check routine, (2) from the field's or form's +initialization or termination hooks, or (3) just after a +REQ_VALIDATION request has been processed by the forms driver</p> +</div> +<div class="SECT3"> +<hr> +<h4 class="SECT3"><a name="FIELDUSERPTR" id="FIELDUSERPTR">18.3.7. +Field User Pointer</a></h4> +<p>Every field structure contains one pointer that can be used by +the user for various purposes. It is not touched by forms library +and can be used for any purpose by the user. The following +functions set and fetch user pointer.</p> +<table border="0" bgcolor="#E0E0E0" width="100%"> +<tr> +<td> +<pre class="PROGRAMLISTING"> +<font color="#000000">int set_field_userptr(FIELD *field, + char *userptr); /* the user pointer you wish to associate */ + /* with the field */ + +char *field_userptr(FIELD *field); /* fetch user pointer of the field */</font> +</pre></td> +</tr> +</table> +</div> +<div class="SECT3"> +<hr> +<h4 class="SECT3"><a name="VARIABLESIZEFIELDS" id= +"VARIABLESIZEFIELDS">18.3.8. Variable-Sized Fields</a></h4> +<p>If you want a dynamically changing field with variable width, +this is the feature you want to put to full use. This will allow +the user to enter more data than the original size of the field and +let the field grow. According to the field orientation it will +scroll horizontally or vertically to incorporate the new data.</p> +<p>To make a field dynamically growable, the option O_STATIC should +be turned off. This can be done with a</p> +<table border="0" bgcolor="#E0E0E0" width="100%"> +<tr> +<td> +<pre class="PROGRAMLISTING"> +<font color= +"#000000"> field_opts_off(field_pointer, O_STATIC);</font> +</pre></td> +</tr> +</table> +<p>But it's usually not advisable to allow a field to grow +infinitely. You can set a maximum limit to the growth of the field +with</p> +<table border="0" bgcolor="#E0E0E0" width="100%"> +<tr> +<td> +<pre class="PROGRAMLISTING"> +<font color= +"#000000">int set_max_field(FIELD *field, /* Field on which to operate */ + int max_growth); /* maximum growth allowed for the field */</font> +</pre></td> +</tr> +</table> +<p>The field info for a dynamically growable field can be retrieved +by</p> +<table border="0" bgcolor="#E0E0E0" width="100%"> +<tr> +<td> +<pre class="PROGRAMLISTING"> +<font color= +"#000000">int dynamic_field_info( FIELD *field, /* Field on which to operate */ + int *prows, /* number of rows will be filled in this */ + int *pcols, /* number of columns will be filled in this*/ + int *pmax) /* maximum allowable growth will be filled */ + /* in this */</font> +</pre></td> +</tr> +</table> +Though field_info work as usual, it is advisable to use this +function to get the proper attributes of a dynamically growable +field. +<p>Recall the library routine new_field; a new field created with +height set to one will be defined to be a one line field. A new +field created with height greater than one will be defined to be a +multi line field.</p> +<p>A one line field with O_STATIC turned off (dynamically growable +field) will contain a single fixed row, but the number of columns +can increase if the user enters more data than the initial field +will hold. The number of columns displayed will remain fixed and +the additional data will scroll horizontally.</p> +<p>A multi line field with O_STATIC turned off (dynamically +growable field) will contain a fixed number of columns, but the +number of rows can increase if the user enters more data than the +initial field will hold. The number of rows displayed will remain +fixed and the additional data will scroll vertically.</p> +<p>The above two paragraphs pretty much describe a dynamically +growable field's behavior. The way other parts of forms library +behaves is described below:</p> +<ol type="1"> +<li> +<p>The field option O_AUTOSKIP will be ignored if the option +O_STATIC is off and there is no maximum growth specified for the +field. Currently, O_AUTOSKIP generates an automatic REQ_NEXT_FIELD +form driver request when the user types in the last character +position of a field. On a growable field with no maximum growth +specified, there is no last character position. If a maximum growth +is specified, the O_AUTOSKIP option will work as normal if the +field has grown to its maximum size.</p> +</li> +<li> +<p>The field justification will be ignored if the option O_STATIC +is off. Currently, set_field_just can be used to JUSTIFY_LEFT, +JUSTIFY_RIGHT, JUSTIFY_CENTER the contents of a one line field. A +growable one line field will, by definition, grow and scroll +horizontally and may contain more data than can be justified. The +return from field_just will be unchanged.</p> +</li> +<li> +<p>The overloaded form driver request REQ_NEW_LINE will operate the +same way regardless of the O_NL_OVERLOAD form option if the field +option O_STATIC is off and there is no maximum growth specified for +the field. Currently, if the form option O_NL_OVERLOAD is on, +REQ_NEW_LINE implicitly generates a REQ_NEXT_FIELD if called from +the last line of a field. If a field can grow without bound, there +is no last line, so REQ_NEW_LINE will never implicitly generate a +REQ_NEXT_FIELD. If a maximum growth limit is specified and the +O_NL_OVERLOAD form option is on, REQ_NEW_LINE will only implicitly +generate REQ_NEXT_FIELD if the field has grown to its maximum size +and the user is on the last line.</p> +</li> +<li> +<p>The library call dup_field will work as usual; it will duplicate +the field, including the current buffer size and contents of the +field being duplicated. Any specified maximum growth will also be +duplicated.</p> +</li> +<li> +<p>The library call link_field will work as usual; it will +duplicate all field attributes and share buffers with the field +being linked. If the O_STATIC field option is subsequently changed +by a field sharing buffers, how the system reacts to an attempt to +enter more data into the field than the buffer will currently hold +will depend on the setting of the option in the current field.</p> +</li> +<li> +<p>The library call field_info will work as usual; the variable +nrow will contain the value of the original call to new_field. The +user should use dynamic_field_info, described above, to query the +current size of the buffer.</p> +</li> +</ol> +<p>Some of the above points make sense only after explaining form +driver. We will be looking into that in next few sections.</p> +</div> +</div> +<div class="SECT2"> +<hr> +<h3 class="SECT2"><a name="FORMWINDOWS" id="FORMWINDOWS">18.4. Form +Windows</a></h3> +<p>The form windows concept is pretty much similar to menu windows. +Every form is associated with a main window and a sub window. The +form main window displays any title or border associated or +whatever the user wishes. Then the sub window contains all the +fields and displays them according to their position. This gives +the flexibility of manipulating fancy form displaying very +easily.</p> +<p>Since this is pretty much similar to menu windows, I am +providing an example with out much explanation. The functions are +similar and they work the same way.</p> +<div class="EXAMPLE"><a name="FFOWI" id="FFOWI"></a> +<p><b>Example 28. Form Windows Example</b></p> +<table border="0" bgcolor="#E0E0E0" width="100%"> +<tr> +<td> +<pre class="PROGRAMLISTING"> +<font color="#000000"><span class= +"INLINEMEDIAOBJECT">#include <form.h> + +void print_in_middle(WINDOW *win, int starty, int startx, int width, char *string, chtype color); + +int main() +{ + FIELD *field[3]; + FORM *my_form; + WINDOW *my_form_win; + int ch, rows, cols; + + /* Initialize curses */ + initscr(); + start_color(); + cbreak(); + noecho(); + keypad(stdscr, TRUE); + + /* Initialize few color pairs */ + init_pair(1, COLOR_RED, COLOR_BLACK); + + /* Initialize the fields */ + field[0] = new_field(1, 10, 6, 1, 0, 0); + field[1] = new_field(1, 10, 8, 1, 0, 0); + field[2] = NULL; + + /* Set field options */ + set_field_back(field[0], A_UNDERLINE); + field_opts_off(field[0], O_AUTOSKIP); /* Don't go to next field when this */ + /* Field is filled up */ + set_field_back(field[1], A_UNDERLINE); + field_opts_off(field[1], O_AUTOSKIP); + + /* Create the form and post it */ + my_form = new_form(field); + + /* Calculate the area required for the form */ + scale_form(my_form, &rows, &cols); + + /* Create the window to be associated with the form */ + my_form_win = newwin(rows + 4, cols + 4, 4, 4); + keypad(my_form_win, TRUE); + + /* Set main window and sub window */ + set_form_win(my_form, my_form_win); + set_form_sub(my_form, derwin(my_form_win, rows, cols, 2, 2)); + + /* Print a border around the main window and print a title */ + box(my_form_win, 0, 0); + print_in_middle(my_form_win, 1, 0, cols + 4, "My Form", COLOR_PAIR(1)); + + post_form(my_form); + wrefresh(my_form_win); + + mvprintw(LINES - 2, 0, "Use UP, DOWN arrow keys to switch between fields"); + refresh(); + + /* Loop through to get user requests */ + while((ch = wgetch(my_form_win)) != KEY_F(1)) + { switch(ch) + { case KEY_DOWN: + /* Go to next field */ + form_driver(my_form, REQ_NEXT_FIELD); + /* Go to the end of the present buffer */ + /* Leaves nicely at the last character */ + form_driver(my_form, REQ_END_LINE); + break; + case KEY_UP: + /* Go to previous field */ + form_driver(my_form, REQ_PREV_FIELD); + form_driver(my_form, REQ_END_LINE); + break; + default: + /* If this is a normal character, it gets */ + /* Printed */ + form_driver(my_form, ch); + break; + } + } + + /* Un post form and free the memory */ + unpost_form(my_form); + free_form(my_form); + free_field(field[0]); + free_field(field[1]); + + endwin(); + return 0; +} + +void print_in_middle(WINDOW *win, int starty, int startx, int width, char *string, chtype color) +{ int length, x, y; + float temp; + + if(win == NULL) + win = stdscr; + getyx(win, y, x); + if(startx != 0) + x = startx; + if(starty != 0) + y = starty; + if(width == 0) + width = 80; + + length = strlen(string); + temp = (width - length)/ 2; + x = startx + (int)temp; + wattron(win, color); + mvwprintw(win, y, x, "%s", string); + wattroff(win, color); + refresh(); +}</span></font> +</pre></td> +</tr> +</table> +</div> +</div> +<div class="SECT2"> +<hr> +<h3 class="SECT2"><a name="FILEDVALIDATE" id="FILEDVALIDATE">18.5. +Field Validation</a></h3> +<p>By default, a field will accept any data input by the user. It +is possible to attach validation to the field. Then any attempt by +the user to leave the field, while it contains data that doesn't +match the validation type will fail. Some validation types also +have a character-validity check for each time a character is +entered in the field.</p> +<p>Validation can be attached to a field with the following +function.</p> +<table border="0" bgcolor="#E0E0E0" width="100%"> +<tr> +<td> +<pre class="PROGRAMLISTING"> +<font color= +"#000000">int set_field_type(FIELD *field, /* field to alter */ + FIELDTYPE *ftype, /* type to associate */ + ...); /* additional arguments*/</font> +</pre></td> +</tr> +</table> +Once set, the validation type for a field can be queried with +<table border="0" bgcolor="#E0E0E0" width="100%"> +<tr> +<td> +<pre class="PROGRAMLISTING"> +<font color= +"#000000">FIELDTYPE *field_type(FIELD *field); /* field to query */</font> +</pre></td> +</tr> +</table> +<p>The form driver validates the data in a field only when data is +entered by the end-user. Validation does not occur when</p> +<ul> +<li> +<p>the application program changes the field value by calling +set_field_buffer.</p> +</li> +<li> +<p>linked field values are changed indirectly -- by changing the +field to which they are linked</p> +</li> +</ul> +<p>The following are the pre-defined validation types. You can also +specify custom validation, though it's a bit tricky and +cumbersome.</p> +<h1 class="BRIDGEHEAD"><a name="AEN1069" id= +"AEN1069"></a>TYPE_ALPHA</h1> +<p>This field type accepts alphabetic data; no blanks, no digits, +no special characters (this is checked at character-entry time). It +is set up with:</p> +<table border="0" bgcolor="#E0E0E0" width="100%"> +<tr> +<td> +<pre class="PROGRAMLISTING"> +<font color= +"#000000">int set_field_type(FIELD *field, /* field to alter */ + TYPE_ALPHA, /* type to associate */ + int width); /* maximum width of field */</font> +</pre></td> +</tr> +</table> +<p>The width argument sets a minimum width of data. The user has to +enter at-least width number of characters before he can leave the +field. Typically you'll want to set this to the field width; if +it's greater than the field width, the validation check will always +fail. A minimum width of zero makes field completion optional.</p> +<h1 class="BRIDGEHEAD"><a name="AEN1073" id= +"AEN1073"></a>TYPE_ALNUM</h1> +<p>This field type accepts alphabetic data and digits; no blanks, +no special characters (this is checked at character-entry time). It +is set up with:</p> +<table border="0" bgcolor="#E0E0E0" width="100%"> +<tr> +<td> +<pre class="PROGRAMLISTING"> +<font color= +"#000000">int set_field_type(FIELD *field, /* field to alter */ + TYPE_ALNUM, /* type to associate */ + int width); /* maximum width of field */</font> +</pre></td> +</tr> +</table> +<p>The width argument sets a minimum width of data. As with +TYPE_ALPHA, typically you'll want to set this to the field width; +if it's greater than the field width, the validation check will +always fail. A minimum width of zero makes field completion +optional.</p> +<h1 class="BRIDGEHEAD"><a name="AEN1077" id= +"AEN1077"></a>TYPE_ENUM</h1> +<p>This type allows you to restrict a field's values to be among a +specified set of string values (for example, the two-letter postal +codes for U.S. states). It is set up with:</p> +<table border="0" bgcolor="#E0E0E0" width="100%"> +<tr> +<td> +<pre class="PROGRAMLISTING"> +<font color= +"#000000">int set_field_type(FIELD *field, /* field to alter */ + TYPE_ENUM, /* type to associate */ + char **valuelist; /* list of possible values */ + int checkcase; /* case-sensitive? */ + int checkunique); /* must specify uniquely? */</font> +</pre></td> +</tr> +</table> +<p>The valuelist parameter must point at a NULL-terminated list of +valid strings. The checkcase argument, if true, makes comparison +with the string case-sensitive.</p> +<p>When the user exits a TYPE_ENUM field, the validation procedure +tries to complete the data in the buffer to a valid entry. If a +complete choice string has been entered, it is of course valid. But +it is also possible to enter a prefix of a valid string and have it +completed for you.</p> +<p>By default, if you enter such a prefix and it matches more than +one value in the string list, the prefix will be completed to the +first matching value. But the checkunique argument, if true, +requires prefix matches to be unique in order to be valid.</p> +<p>The REQ_NEXT_CHOICE and REQ_PREV_CHOICE input requests can be +particularly useful with these fields.</p> +<h1 class="BRIDGEHEAD"><a name="AEN1084" id= +"AEN1084"></a>TYPE_INTEGER</h1> +<p>This field type accepts an integer. It is set up as follows:</p> +<table border="0" bgcolor="#E0E0E0" width="100%"> +<tr> +<td> +<pre class="PROGRAMLISTING"> +<font color= +"#000000">int set_field_type(FIELD *field, /* field to alter */ + TYPE_INTEGER, /* type to associate */ + int padding, /* # places to zero-pad to */ + int vmin, int vmax); /* valid range */</font> +</pre></td> +</tr> +</table> +<p>Valid characters consist of an optional leading minus and +digits. The range check is performed on exit. If the range maximum +is less than or equal to the minimum, the range is ignored.</p> +<p>If the value passes its range check, it is padded with as many +leading zero digits as necessary to meet the padding argument.</p> +<p>A TYPE_INTEGER value buffer can conveniently be interpreted with +the C library function atoi(3).</p> +<h1 class="BRIDGEHEAD"><a name="AEN1090" id= +"AEN1090"></a>TYPE_NUMERIC</h1> +<p>This field type accepts a decimal number. It is set up as +follows:</p> +<table border="0" bgcolor="#E0E0E0" width="100%"> +<tr> +<td> +<pre class="PROGRAMLISTING"> +<font color= +"#000000">int set_field_type(FIELD *field, /* field to alter */ + TYPE_NUMERIC, /* type to associate */ + int padding, /* # places of precision */ + int vmin, int vmax); /* valid range */</font> +</pre></td> +</tr> +</table> +<p>Valid characters consist of an optional leading minus and +digits. possibly including a decimal point. The range check is +performed on exit. If the range maximum is less than or equal to +the minimum, the range is ignored.</p> +<p>If the value passes its range check, it is padded with as many +trailing zero digits as necessary to meet the padding argument.</p> +<p>A TYPE_NUMERIC value buffer can conveniently be interpreted with +the C library function atof(3).</p> +<h1 class="BRIDGEHEAD"><a name="AEN1096" id= +"AEN1096"></a>TYPE_REGEXP</h1> +<p>This field type accepts data matching a regular expression. It +is set up as follows:</p> +<table border="0" bgcolor="#E0E0E0" width="100%"> +<tr> +<td> +<pre class="PROGRAMLISTING"> +<font color= +"#000000">int set_field_type(FIELD *field, /* field to alter */ + TYPE_REGEXP, /* type to associate */ + char *regexp); /* expression to match */</font> +</pre></td> +</tr> +</table> +<p>The syntax for regular expressions is that of regcomp(3). The +check for regular-expression match is performed on exit.</p> +</div> +<div class="SECT2"> +<hr> +<h3 class="SECT2"><a name="FORMDRIVER" id="FORMDRIVER">18.6. Form +Driver: The work horse of the forms system</a></h3> +<p>As in the menu system, form_driver() plays a very important role +in forms system. All types of requests to forms system should be +funneled through form_driver().</p> +<table border="0" bgcolor="#E0E0E0" width="100%"> +<tr> +<td> +<pre class="PROGRAMLISTING"> +<font color= +"#000000">int form_driver(FORM *form, /* form on which to operate */ + int request) /* form request code */</font> +</pre></td> +</tr> +</table> +<p>As you have seen some of the examples above, you have to be in a +loop looking for user input and then decide whether it's a field +data or a form request. The form requests are then passed to +form_driver() to do the work.</p> +<p>The requests roughly can be divided into following categories. +Different requests and their usage is explained below:</p> +<div class="SECT3"> +<hr> +<h4 class="SECT3"><a name="PAGENAVREQ" id="PAGENAVREQ">18.6.1. Page +Navigation Requests</a></h4> +<p>These requests cause page-level moves through the form, +triggering display of a new form screen. A form can be made of +multiple pages. If you have a big form with lot of fields and +logical sections, then you can divide the form into pages. The +function set_new_page() to set a new page at the field +specified.</p> +<table border="0" bgcolor="#E0E0E0" width="100%"> +<tr> +<td> +<pre class="PROGRAMLISTING"> +<font color= +"#000000">int set_new_page(FIELD *field,/* Field at which page break to be set or unset */ + bool new_page_flag); /* should be TRUE to put a break */</font> +</pre></td> +</tr> +</table> +<p>The following requests allow you to move to different pages</p> +<ul> +<li> +<p><em>REQ_NEXT_PAGE</em> Move to the next form page.</p> +</li> +<li> +<p><em>REQ_PREV_PAGE</em> Move to the previous form page.</p> +</li> +<li> +<p><em>REQ_FIRST_PAGE</em> Move to the first form page.</p> +</li> +<li> +<p><em>REQ_LAST_PAGE</em> Move to the last form page.</p> +</li> +</ul> +<p>These requests treat the list as cyclic; that is, REQ_NEXT_PAGE +from the last page goes to the first, and REQ_PREV_PAGE from the +first page goes to the last.</p> +</div> +<div class="SECT3"> +<hr> +<h4 class="SECT3"><a name="INTERFIELDNAVREQ" id= +"INTERFIELDNAVREQ">18.6.2. Inter-Field Navigation Requests</a></h4> +<p>These requests handle navigation between fields on the same +page.</p> +<ul> +<li> +<p><em>REQ_NEXT_FIELD</em> Move to next field.</p> +</li> +<li> +<p><em>REQ_PREV_FIELD</em> Move to previous field.</p> +</li> +<li> +<p><em>REQ_FIRST_FIELD</em> Move to the first field.</p> +</li> +<li> +<p><em>REQ_LAST_FIELD</em> Move to the last field.</p> +</li> +<li> +<p><em>REQ_SNEXT_FIELD</em> Move to sorted next field.</p> +</li> +<li> +<p><em>REQ_SPREV_FIELD</em> Move to sorted previous field.</p> +</li> +<li> +<p><em>REQ_SFIRST_FIELD</em> Move to the sorted first field.</p> +</li> +<li> +<p><em>REQ_SLAST_FIELD</em> Move to the sorted last field.</p> +</li> +<li> +<p><em>REQ_LEFT_FIELD</em> Move left to field.</p> +</li> +<li> +<p><em>REQ_RIGHT_FIELD</em> Move right to field.</p> +</li> +<li> +<p><em>REQ_UP_FIELD</em> Move up to field.</p> +</li> +<li> +<p><em>REQ_DOWN_FIELD</em> Move down to field.</p> +</li> +</ul> +<p>These requests treat the list of fields on a page as cyclic; +that is, REQ_NEXT_FIELD from the last field goes to the first, and +REQ_PREV_FIELD from the first field goes to the last. The order of +the fields for these (and the REQ_FIRST_FIELD and REQ_LAST_FIELD +requests) is simply the order of the field pointers in the form +array (as set up by new_form() or set_form_fields()</p> +<p>It is also possible to traverse the fields as if they had been +sorted in screen-position order, so the sequence goes left-to-right +and top-to-bottom. To do this, use the second group of four +sorted-movement requests.</p> +<p>Finally, it is possible to move between fields using visual +directions up, down, right, and left. To accomplish this, use the +third group of four requests. Note, however, that the position of a +form for purposes of these requests is its upper-left corner.</p> +<p>For example, suppose you have a multi-line field B, and two +single-line fields A and C on the same line with B, with A to the +left of B and C to the right of B. A REQ_MOVE_RIGHT from A will go +to B only if A, B, and C all share the same first line; otherwise +it will skip over B to C.</p> +</div> +<div class="SECT3"> +<hr> +<h4 class="SECT3"><a name="INTRAFIELDNAVREQ" id= +"INTRAFIELDNAVREQ">18.6.3. Intra-Field Navigation Requests</a></h4> +<p>These requests drive movement of the edit cursor within the +currently selected field.</p> +<ul> +<li> +<p><em>REQ_NEXT_CHAR</em> Move to next character.</p> +</li> +<li> +<p><em>REQ_PREV_CHAR</em> Move to previous character.</p> +</li> +<li> +<p><em>REQ_NEXT_LINE</em> Move to next line.</p> +</li> +<li> +<p><em>REQ_PREV_LINE</em> Move to previous line.</p> +</li> +<li> +<p><em>REQ_NEXT_WORD</em> Move to next word.</p> +</li> +<li> +<p><em>REQ_PREV_WORD</em> Move to previous word.</p> +</li> +<li> +<p><em>REQ_BEG_FIELD</em> Move to beginning of field.</p> +</li> +<li> +<p><em>REQ_END_FIELD</em> Move to end of field.</p> +</li> +<li> +<p><em>REQ_BEG_LINE</em> Move to beginning of line.</p> +</li> +<li> +<p><em>REQ_END_LINE</em> Move to end of line.</p> +</li> +<li> +<p><em>REQ_LEFT_CHAR</em> Move left in field.</p> +</li> +<li> +<p><em>REQ_RIGHT_CHAR</em> Move right in field.</p> +</li> +<li> +<p><em>REQ_UP_CHAR</em> Move up in field.</p> +</li> +<li> +<p><em>REQ_DOWN_CHAR</em> Move down in field.</p> +</li> +</ul> +<p>Each word is separated from the previous and next characters by +whitespace. The commands to move to beginning and end of line or +field look for the first or last non-pad character in their +ranges.</p> +</div> +<div class="SECT3"> +<hr> +<h4 class="SECT3"><a name="SCROLLREQ" id="SCROLLREQ">18.6.4. +Scrolling Requests</a></h4> +<p>Fields that are dynamic and have grown and fields explicitly +created with offscreen rows are scrollable. One-line fields scroll +horizontally; multi-line fields scroll vertically. Most scrolling +is triggered by editing and intra-field movement (the library +scrolls the field to keep the cursor visible). It is possible to +explicitly request scrolling with the following requests:</p> +<ul> +<li> +<p><em>REQ_SCR_FLINE</em> Scroll vertically forward a line.</p> +</li> +<li> +<p><em>REQ_SCR_BLINE</em> Scroll vertically backward a line.</p> +</li> +<li> +<p><em>REQ_SCR_FPAGE</em> Scroll vertically forward a page.</p> +</li> +<li> +<p><em>REQ_SCR_BPAGE</em> Scroll vertically backward a page.</p> +</li> +<li> +<p><em>REQ_SCR_FHPAGE</em> Scroll vertically forward half a +page.</p> +</li> +<li> +<p><em>REQ_SCR_BHPAGE</em> Scroll vertically backward half a +page.</p> +</li> +<li> +<p><em>REQ_SCR_FCHAR</em> Scroll horizontally forward a +character.</p> +</li> +<li> +<p><em>REQ_SCR_BCHAR</em> Scroll horizontally backward a +character.</p> +</li> +<li> +<p><em>REQ_SCR_HFLINE</em> Scroll horizontally one field width +forward.</p> +</li> +<li> +<p><em>REQ_SCR_HBLINE</em> Scroll horizontally one field width +backward.</p> +</li> +<li> +<p><em>REQ_SCR_HFHALF</em> Scroll horizontally one half field width +forward.</p> +</li> +<li> +<p><em>REQ_SCR_HBHALF</em> Scroll horizontally one half field width +backward.</p> +</li> +</ul> +<p>For scrolling purposes, a page of a field is the height of its +visible part.</p> +</div> +<div class="SECT3"> +<hr> +<h4 class="SECT3"><a name="EDITREQ" id="EDITREQ">18.6.5. Editing +Requests</a></h4> +<p>When you pass the forms driver an ASCII character, it is treated +as a request to add the character to the field's data buffer. +Whether this is an insertion or a replacement depends on the +field's edit mode (insertion is the default.</p> +<p>The following requests support editing the field and changing +the edit mode:</p> +<ul> +<li> +<p><em>REQ_INS_MODE</em> Set insertion mode.</p> +</li> +<li> +<p><em>REQ_OVL_MODE</em> Set overlay mode.</p> +</li> +<li> +<p><em>REQ_NEW_LINE</em> New line request (see below for +explanation).</p> +</li> +<li> +<p><em>REQ_INS_CHAR</em> Insert space at character location.</p> +</li> +<li> +<p><em>REQ_INS_LINE</em> Insert blank line at character +location.</p> +</li> +<li> +<p><em>REQ_DEL_CHAR</em> Delete character at cursor.</p> +</li> +<li> +<p><em>REQ_DEL_PREV</em> Delete previous word at cursor.</p> +</li> +<li> +<p><em>REQ_DEL_LINE</em> Delete line at cursor.</p> +</li> +<li> +<p><em>REQ_DEL_WORD</em> Delete word at cursor.</p> +</li> +<li> +<p><em>REQ_CLR_EOL</em> Clear to end of line.</p> +</li> +<li> +<p><em>REQ_CLR_EOF</em> Clear to end of field.</p> +</li> +<li> +<p><em>REQ_CLR_FIELD</em> Clear entire field.</p> +</li> +</ul> +<p>The behavior of the REQ_NEW_LINE and REQ_DEL_PREV requests is +complicated and partly controlled by a pair of forms options. The +special cases are triggered when the cursor is at the beginning of +a field, or on the last line of the field.</p> +<p>First, we consider REQ_NEW_LINE:</p> +<p>The normal behavior of REQ_NEW_LINE in insert mode is to break +the current line at the position of the edit cursor, inserting the +portion of the current line after the cursor as a new line +following the current and moving the cursor to the beginning of +that new line (you may think of this as inserting a newline in the +field buffer).</p> +<p>The normal behavior of REQ_NEW_LINE in overlay mode is to clear +the current line from the position of the edit cursor to end of +line. The cursor is then moved to the beginning of the next +line.</p> +<p>However, REQ_NEW_LINE at the beginning of a field, or on the +last line of a field, instead does a REQ_NEXT_FIELD. O_NL_OVERLOAD +option is off, this special action is disabled.</p> +<p>Now, let us consider REQ_DEL_PREV:</p> +<p>The normal behavior of REQ_DEL_PREV is to delete the previous +character. If insert mode is on, and the cursor is at the start of +a line, and the text on that line will fit on the previous one, it +instead appends the contents of the current line to the previous +one and deletes the current line (you may think of this as deleting +a newline from the field buffer).</p> +<p>However, REQ_DEL_PREV at the beginning of a field is instead +treated as a REQ_PREV_FIELD.</p> +<p>If the O_BS_OVERLOAD option is off, this special action is +disabled and the forms driver just returns E_REQUEST_DENIED.</p> +</div> +<div class="SECT3"> +<hr> +<h4 class="SECT3"><a name="ORDERREQ" id="ORDERREQ">18.6.6. Order +Requests</a></h4> +<p>If the type of your field is ordered, and has associated +functions for getting the next and previous values of the type from +a given value, there are requests that can fetch that value into +the field buffer:</p> +<ul> +<li> +<p><em>REQ_NEXT_CHOICE</em> Place the successor value of the +current value in the buffer.</p> +</li> +<li> +<p><em>REQ_PREV_CHOICE</em> Place the predecessor value of the +current value in the buffer.</p> +</li> +</ul> +<p>Of the built-in field types, only TYPE_ENUM has built-in +successor and predecessor functions. When you define a field type +of your own (see Custom Validation Types), you can associate our +own ordering functions.</p> +</div> +<div class="SECT3"> +<hr> +<h4 class="SECT3"><a name="APPLICCOMMANDS" id= +"APPLICCOMMANDS">18.6.7. Application Commands</a></h4> +<p>Form requests are represented as integers above the curses value +greater than KEY_MAX and less than or equal to the constant +MAX_COMMAND. A value within this range gets ignored by +form_driver(). So this can be used for any purpose by the +application. It can be treated as an application specific action +and take corresponding action.</p> +</div> +</div> +</div> +<div class="SECT1"> +<hr> +<h2 class="SECT1"><a name="TOOLS" id="TOOLS">19. Tools and Widget +Libraries</a></h2> +<p>Now that you have seen the capabilities of ncurses and its +sister libraries, you are rolling your sleeves up and gearing for a +project that heavily manipulates screen. But wait.. It can be +pretty difficult to write and maintain complex GUI widgets in plain +ncurses or even with the additional libraries. There are some +ready-to-use tools and widget libraries that can be used instead of +writing your own widgets. You can use some of them, get ideas from +the code, or even extend them.</p> +<div class="SECT2"> +<hr> +<h3 class="SECT2"><a name="CDK" id="CDK">19.1. CDK (Curses +Development Kit)</a></h3> +<p>In the author's words</p> +<p><em>CDK stands for 'Curses Development Kit' and it currently +contains 21 ready to use widgets which facilitate the speedy +development of full screen curses programs.</em></p> +<p>The kit provides some useful widgets, which can be used in your +programs directly. It's pretty well written and the documentation +is very good. The examples in the examples directory can be a good +place to start for beginners. The CDK can be downloaded from +<a href="http://invisible-island.net/cdk/" target= +"_top">http://invisible-island.net/cdk/</a> . Follow the +instructions in README file to install it.</p> +<div class="SECT3"> +<hr> +<h4 class="SECT3"><a name="WIDGETLIST" id="WIDGETLIST">19.1.1. +Widget List</a></h4> +<p>The following is the list of widgets provided with cdk and their +description.</p> +<table border="0" bgcolor="#E0E0E0" width="100%"> +<tr> +<td> +<pre class="PROGRAMLISTING"> +<font color="#000000">Widget Type Quick Description +=========================================================================== +Alphalist Allows a user to select from a list of words, with + the ability to narrow the search list by typing in a + few characters of the desired word. +Buttonbox This creates a multiple button widget. +Calendar Creates a little simple calendar widget. +Dialog Prompts the user with a message, and the user + can pick an answer from the buttons provided. +Entry Allows the user to enter various types of information. +File Selector A file selector built from Cdk base widgets. This + example shows how to create more complicated widgets + using the Cdk widget library. +Graph Draws a graph. +Histogram Draws a histogram. +Item List Creates a pop up field which allows the user to select + one of several choices in a small field. Very useful + for things like days of the week or month names. +Label Displays messages in a pop up box, or the label can be + considered part of the screen. +Marquee Displays a message in a scrolling marquee. +Matrix Creates a complex matrix with lots of options. +Menu Creates a pull-down menu interface. +Multiple Line Entry A multiple line entry field. Very useful + for long fields. (like a description + field) +Radio List Creates a radio button list. +Scale Creates a numeric scale. Used for allowing a user to + pick a numeric value and restrict them to a range of + values. +Scrolling List Creates a scrolling list/menu list. +Scrolling Window Creates a scrolling log file viewer. Can add + information into the window while its running. + A good widget for displaying the progress of + something. (akin to a console window) +Selection List Creates a multiple option selection list. +Slider Akin to the scale widget, this widget provides a + visual slide bar to represent the numeric value. +Template Creates a entry field with character sensitive + positions. Used for pre-formatted fields like + dates and phone numbers. +Viewer This is a file/information viewer. Very useful + when you need to display loads of information. +===========================================================================</font> +</pre></td> +</tr> +</table> +<p>A few of the widgets are modified by Thomas Dickey in recent +versions.</p> +</div> +<div class="SECT3"> +<hr> +<h4 class="SECT3"><a name="CDKATTRACT" id="CDKATTRACT">19.1.2. Some +Attractive Features</a></h4> +<p>Apart from making our life easier with readily usable widgets, +cdk solves one frustrating problem with printing multi colored +strings, justified strings elegantly. Special formatting tags can +be embedded in the strings which are passed to CDK functions. For +Example</p> +<p>If the string</p> +<table border="0" bgcolor="#E0E0E0" width="100%"> +<tr> +<td> +<pre class="PROGRAMLISTING"> +<font color= +"#000000">"</B/1>This line should have a yellow foreground and a blue +background.<!1>"</font> +</pre></td> +</tr> +</table> +<p>given as a parameter to newCDKLabel(), it prints the line with +yellow foreground and blue background. There are other tags +available for justifying string, embedding special drawing +characters etc.. Please refer to the man page cdk_display(3X) for +details. The man page explains the usage with nice examples.</p> +</div> +<div class="SECT3"> +<hr> +<h4 class="SECT3"><a name="CDKCONCLUSION" id= +"CDKCONCLUSION">19.1.3. Conclusion</a></h4> +<p>All in all, CDK is a well-written package of widgets, which if +used properly can form a strong frame work for developing complex +GUI.</p> +</div> +</div> +<div class="SECT2"> +<hr> +<h3 class="SECT2"><a name="DIALOG" id="DIALOG">19.2. The +dialog</a></h3> +<p>Long long ago, in September 1994, when few people knew linux, +Jeff Tranter wrote an <a href= +"http://www2.linuxjournal.com/lj-issues/issue5/2807.html" target= +"_top">article</a> on dialog in Linux Journal. He starts the +article with these words..</p> +<p><em>Linux is based on the Unix operating system, but also +features a number of unique and useful kernel features and +application programs that often go beyond what is available under +Unix. One little-known gem is "dialog", a utility for creating +professional-looking dialog boxes from within shell scripts. This +article presents a tutorial introduction to the dialog utility, and +shows examples of how and where it can be used</em></p> +<p>As he explains, dialog is a real gem in making +professional-looking dialog boxes with ease. It creates a variety +of dialog boxes, menus, check lists etc.. It is usually installed +by default. If not, you can download it from <a href= +"http://invisible-island.net/dialog/" target="_top">Thomas +Dickey</a>'s site.</p> +<p>The above-mentioned article gives a very good overview of its +uses and capabilites. The man page has more details. It can be used +in variety of situations. One good example is building of linux +kernel in text mode. Linux kernel uses a modified version of dialog +tailored for its needs.</p> +<p>dialog was initially designed to be used with shell scripts. If +you want to use its functionality in a c program, then you can use +libdialog. The documentation regarding this is sparse. Definitive +reference is the dialog.h header file which comes with the library. +You may need to hack here and there to get the required output. The +source is easily customizable. I have used it on a number of +occasions by modifying the code.</p> +</div> +<div class="SECT2"> +<hr> +<h3 class="SECT2"><a name="PERLCURSES" id="PERLCURSES">19.3. Perl +Curses Modules CURSES::FORM and CURSES::WIDGETS</a></h3> +<p>The perl module Curses, Curses::Form and Curses::Widgets give +access to curses from perl. If you have curses and basic perl is +installed, you can get these modules from <a href= +"http://www.cpan.org/modules/01modules.index.html" target= +"_top">CPAN All Modules page</a>. Get the three zipped modules in +the Curses category. Once installed you can use these modules from +perl scripts like any other module. For more information on perl +modules see perlmod man page. The above modules come with good +documentation and they have some demo scripts to test the +functionality. Though the widgets provided are very rudimentary, +these modules provide good access to curses library from perl.</p> +<p>Some of my code examples are converted to perl by Anuradha +Ratnaweera and they are available in the <var class= +"LITERAL">perl</var> directory.</p> +<p>For more information see man pages Curses(3) , Curses::Form(3) +and Curses::Widgets(3). These pages are installed only when the +above modules are acquired and installed.</p> +</div> +</div> +<div class="SECT1"> +<hr> +<h2 class="SECT1"><a name="JUSTFORFUN" id="JUSTFORFUN">20. Just For +Fun !!!</a></h2> +<p>This section contains few programs written by me just for fun. +They don't signify a better programming practice or the best way of +using ncurses. They are provided here so as to allow beginners to +get ideas and add more programs to this section. If you have +written a couple of nice, simple programs in curses and want them +to included here, contact <a href="mailto:ppadala@gmail.com" +target="_top">me</a>.</p> +<div class="SECT2"> +<hr> +<h3 class="SECT2"><a name="GAMEOFLIFE" id="GAMEOFLIFE">20.1. The +Game of Life</a></h3> +<p>Game of life is a wonder of math. In <a href= +"http://www.math.com/students/wonders/life/life.html" target= +"_top">Paul Callahan</a>'s words</p> +<table border="0" bgcolor="#E0E0E0" width="100%"> +<tr> +<td> +<pre class="PROGRAMLISTING"> +<font color= +"#000000"><em>The Game of Life (or simply Life) is not a game in the conventional sense. There +are no players, and no winning or losing. Once the "pieces" are placed in the +starting position, the rules determine everything that happens later. +Nevertheless, Life is full of surprises! In most cases, it is impossible to look +at a starting position (or pattern) and see what will happen in the future. The +only way to find out is to follow the rules of the game.</em></font> +</pre></td> +</tr> +</table> +<p>This program starts with a simple inverted U pattern and shows +how wonderful life works. There is a lot of room for improvement in +the program. You can let the user enter pattern of his choice or +even take input from a file. You can also change rules and play +with a lot of variations. Search on <a href="http://www.google.com" +target="_top">google</a> for interesting information on game of +life.</p> +<p><em>File Path: JustForFun/life.c</em></p> +</div> +<div class="SECT2"> +<hr> +<h3 class="SECT2"><a name="MAGIC" id="MAGIC">20.2. Magic +Square</a></h3> +<p>Magic Square, another wonder of math, is very simple to +understand but very difficult to make. In a magic square sum of the +numbers in each row, each column is equal. Even diagnol sum can be +equal. There are many variations which have special properties.</p> +<p>This program creates a simple magic square of odd order.</p> +<p><em>File Path: JustForFun/magic.c</em></p> +</div> +<div class="SECT2"> +<hr> +<h3 class="SECT2"><a name="HANOI" id="HANOI">20.3. Towers of +Hanoi</a></h3> +<p>The famous towers of hanoi solver. The aim of the game is to +move the disks on the first peg to last peg, using middle peg as a +temporary stay. The catch is not to place a larger disk over a +small disk at any time.</p> +<p><em>File Path: JustForFun/hanoi.c</em></p> +</div> +<div class="SECT2"> +<hr> +<h3 class="SECT2"><a name="QUEENS" id="QUEENS">20.4. Queens +Puzzle</a></h3> +<p>The objective of the famous N-Queen puzzle is to put N queens on +a N X N chess board without attacking each other.</p> +<p>This program solves it with a simple backtracking technique.</p> +<p><em>File Path: JustForFun/queens.c</em></p> +</div> +<div class="SECT2"> +<hr> +<h3 class="SECT2"><a name="SHUFFLE" id="SHUFFLE">20.5. +Shuffle</a></h3> +<p>A fun game, if you have time to kill.</p> +<p><em>File Path: JustForFun/shuffle.c</em></p> +</div> +<div class="SECT2"> +<hr> +<h3 class="SECT2"><a name="TT" id="TT">20.6. Typing Tutor</a></h3> +<p>A simple typing tutor, I created more out of need than for ease +of use. If you know how to put your fingers correctly on the +keyboard, but lack practice, this can be helpful.</p> +<p><em>File Path: JustForFun/tt.c</em></p> +</div> +</div> +<div class="SECT1"> +<hr> +<h2 class="SECT1"><a name="REF" id="REF">21. References</a></h2> +<ul> +<li> +<p>NCURSES man pages</p> +</li> +<li> +<p>NCURSES FAQ at <a href= +"http://invisible-island.net/ncurses/ncurses.faq.html" target= +"_top">http://invisible-island.net/ncurses/ncurses.faq.html</a></p> +</li> +<li> +<p>Writing programs with NCURSES by Eric Raymond and Zeyd M. +Ben-Halim at <a href= +"http://invisible-island.net/ncurses/ncurses-intro.html" target= +"_top">http://invisible-island.net/ncurses/ncurses-intro.html</a> - +somewhat obsolete. I was inspired by this document and the +structure of this HOWTO follows from the original document</p> +</li> +</ul> +</div> +</div> +</body> +</html> |