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/* This work is copyrighted. See COPYRIGHT.OLD & COPYRIGHT.NEW for *
* details. If they are missing then this copy is in violation of *
* the copyright conditions. */
/*
** lib_scroll.c
**
** The routine wscrl(win, n).
** positive n scroll the window up (ie. move lines down)
** negative n scroll the window down (ie. move lines up)
**
*/
#include <stdlib.h>
#include "curses.priv.h"
#include <nterm.h>
int
wscrl(WINDOW *win, int n)
{
int line, i;
chtype *ptr, *temp;
chtype **saved;
chtype blank = ' ';
T(("wscrl(%x,%d) called", win, n));
if (! win->_scroll)
return ERR;
if (n == 0)
return OK;
/* test for scrolling region == entire screen */
saved = (chtype **)malloc(sizeof(chtype *) * abs(n));
if (n < 0) {
/* save overwritten lines */
for (i = 0; i < -n; i++)
saved[i] = win->_line[win->_regbottom-i];
/* shift n lines */
for (line = win->_regbottom; line > win->_regtop+n; line--)
win->_line[line] = win->_line[line+n];
/* restore saved lines and blank them */
for (i = 0, line = win->_regtop; line < win->_regtop-n; line++, i++) {
win->_line[line] = saved[i];
temp = win->_line[line];
for (ptr = temp; ptr - temp <= win->_maxx; ptr++)
*ptr = blank;
}
}
if (n > 0) {
/* save overwritten lines */
for (i = 0; i < n; i++)
saved[i] = win->_line[win->_regtop+i];
/* shift n lines */
for (line = win->_regtop; line < win->_regbottom; line++)
win->_line[line] = win->_line[line+n];
/* restore saved lines and blank them */
for (i = 0, line = win->_regbottom; line > win->_regbottom - n; line--, i++) {
win->_line[line] = saved[i];
temp = win->_line[line];
for (ptr = temp; ptr - temp <= win->_maxx; ptr++)
*ptr = blank;
}
}
free(saved);
/* as an optimization, if the scrolling region is the entire screen
scroll the physical screen */
/* should we extend this to include smaller scrolling ranges by using
change_scroll_region? */
if (win->_maxx == columns && win->_regtop == 0 && win->_regbottom == lines) {
wrefresh(win);
/* at the moment this relies on scroll_reverse and scroll_forward
or parm_rindex and parm_index.
we should add idl support as an alternative */
if (n > 0) {
mvcur(-1, -1, win->_regtop, 0);
if (parm_rindex) {
putp(tparm(parm_rindex, n));
} else if (scroll_reverse) {
while (n--)
putp(scroll_reverse);
}
}
if (n < 0) {
mvcur(-1, -1, win->_regbottom, columns);
n = abs(n);
if (parm_index) {
putp(tparm(parm_index, n));
} else if (scroll_forward) {
while (n--)
putp(scroll_forward);
}
}
mvcur(-1, -1, win->_cury, win->_curx);
} else
touchline(win, win->_regtop, win->_regbottom - win->_regtop + 1);
return OK;
}
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