- Fixed issue #10746: Border size reducement algorithm fails for polygones

  with edge lengths < reducement
  # Modifications in comparision files because some invisible small shapes 
  # were not rendered any more

5 files changed, 109 insertions, 6 deletions

diff --git a/src/driver/flash.php b/src/driver/flash.php
index 409b107..38c07a2 100644
--- a/src/driver/flash.php
+++ b/src/driver/flash.php
@@ -194,7 +194,14 @@ class ezcGraphFlashDriver extends ezcGraphDriver
         {
             // The middle of the border is on the outline of a polygon in ming, 
             // fix that:
-            $points = $this->reducePolygonSize( $points, $thickness / 2 );
+            try
+            {
+                $points = $this->reducePolygonSize( $points, $thickness / 2 );
+            }
+            catch( ezcGraphReducementFailedException $e )
+            {
+                return false;
+            }
         }
 
         $shape = new SWFShape();
@@ -616,7 +623,14 @@ class ezcGraphFlashDriver extends ezcGraphDriver
 
         if ( !$filled )
         {
-            $reduced = $this->reduceEllipseSize( $center, $width, $height, $startAngle, $endAngle, .5 );
+            try
+            {
+                $reduced = $this->reduceEllipseSize( $center, $width, $height, $startAngle, $endAngle, .5 );
+            }
+            catch( ezcGraphReducementFailedException $e )
+            {
+                return false;
+            }
 
             $startAngle = $reduced['startAngle'];
             $endAngle = $reduced['endAngle'];
diff --git a/src/driver/svg.php b/src/driver/svg.php
index daaa7c5..18ce4bd 100644
--- a/src/driver/svg.php
+++ b/src/driver/svg.php
@@ -332,7 +332,13 @@ class ezcGraphSvgDriver extends ezcGraphDriver
         {
             // The middle of the border is on the outline of a polygon in SVG, 
             // fix that:
-            $points = $this->reducePolygonSize( $points, $thickness / 2 );
+            try
+            {
+                $points = $this->reducePolygonSize( $points, $thickness / 2 );
+            } catch ( ezcGraphReducementFailedException $e )
+            {
+                return false;
+            }
         }
 
         $lastPoint = end( $points );
@@ -845,7 +851,13 @@ class ezcGraphSvgDriver extends ezcGraphDriver
         }
         else
         {
-            $reduced = $this->reduceEllipseSize( $center, $width * 2, $height * 2, $startAngle, $endAngle, .5 );
+            try
+            {
+                $reduced = $this->reduceEllipseSize( $center, $width * 2, $height * 2, $startAngle, $endAngle, .5 );
+            } catch ( ezcGraphReducementFailedException $e )
+            {
+                return false;
+            }
 
             $arc = $this->dom->createElement( 'path' );
             $arc->setAttribute( 'd', sprintf( 'M %.2f,%.2f L %.2f,%.2f A %.2f,%.2f 0 %d,1 %.2f,%.2f z',
diff --git a/src/exceptions/reducement_failed.php b/src/exceptions/reducement_failed.php
new file mode 100644
index 0000000..f14e88d
--- /dev/null
+++ b/src/exceptions/reducement_failed.php
@@ -0,0 +1,25 @@
+<?php
+/**
+ * File containing the ezcGraphReducementFailedException class
+ *
+ * @package Graph
+ * @version //autogen//
+ * @copyright Copyright (C) 2005-2007 eZ systems as. All rights reserved.
+ * @license http://ez.no/licenses/new_bsd New BSD License
+ */
+/**
+ * Exception thrown when a requested reducement of an ellipse or polygone 
+ * failed because the shape was already too small.
+ *
+ * @package Graph
+ * @version //autogen//
+ */
+class ezcGraphReducementFailedException extends ezcGraphException
+{
+    public function __construct()
+    {
+        parent::__construct( "Reducement of shape failed, because it was already too small." );
+    }
+}
+
+?>
diff --git a/src/graph_autoload.php b/src/graph_autoload.php
index 1ee0bd1..12aea2b 100644
--- a/src/graph_autoload.php
+++ b/src/graph_autoload.php
@@ -12,6 +12,7 @@
 return array(
     'ezcGraphException'                             => 'Graph/exceptions/exception.php',
     'ezcGraphDatasetAverageInvalidKeysException'    => 'Graph/exceptions/invalid_keys.php',
+    'ezcGraphReducementFailedException'             => 'Graph/exceptions/reducement_failed.php',
     'ezcGraphErrorParsingDateException'             => 'Graph/exceptions/date_parsing.php',
     'ezcGraphFlashBitmapBoundingsException'         => 'Graph/exceptions/flash_bitmap_boundings.php',
     'ezcGraphFlashBitmapTypeException'              => 'Graph/exceptions/flash_bitmap_type.php',
diff --git a/src/interfaces/driver.php b/src/interfaces/driver.php
index 04025ac..a477eea 100644
--- a/src/interfaces/driver.php
+++ b/src/interfaces/driver.php
@@ -95,6 +95,7 @@ abstract class ezcGraphDriver
      * 
      * @param array( ezcGraphCoordinate ) $points 
      * @param float $size 
+     * @throws ezcGraphReducementFailedException
      * @return array( ezcGraphCoordinate )
      */
     protected function reducePolygonSize( array $points, $size )
@@ -107,8 +108,14 @@ abstract class ezcGraphDriver
         {
             $nextPoint = ( $i + 1 ) % $pointCount;
             $vectors[$i] = ezcGraphVector::fromCoordinate( $points[$nextPoint] )
-                            ->sub( $points[$i] )
-                            ->unify();
+                            ->sub( $points[$i] );
+
+            // Throw exception if polygon is too small to reduce
+            if ( $vectors[$i]->length() < $size )
+            {
+                throw new ezcGraphReducementFailedException();
+            }
+            $vectors[$i]->unify();
 
             if ( ( $vectors[$i]->x == $vectors[$i]->y ) && ( $vectors[$i]->x == 0 ) )
             {
@@ -218,6 +225,7 @@ abstract class ezcGraphDriver
      * @param mixed $startAngle 
      * @param mixed $endAngle 
      * @param mixed $size 
+     * @throws ezcGraphReducementFailedException
      * @return array
      */
     protected function reduceEllipseSize( ezcGraphCoordinate $center, $width, $height, $startAngle, $endAngle, $size )
@@ -254,6 +262,49 @@ abstract class ezcGraphDriver
         $centerMovement = clone $unifiedStartVector;
         $newCenter = $v->add( $centerMovement->scalar( $size / tan( ( $endAngle - $startAngle ) / 2 ) ) )->add( $center );
 
+        // Test if center is still inside the ellipse, otherwise the sector 
+        // was to small to be reduced
+        $innerBoundingBoxSize = 0.7 * min( $width, $height );
+        if ( ( $newCenter->x < ( $center->x + $innerBoundingBoxSize ) ) &&
+             ( $newCenter->x > ( $center->x - $innerBoundingBoxSize ) ) &&
+             ( $newCenter->y < ( $center->y + $innerBoundingBoxSize ) ) &&
+             ( $newCenter->y > ( $center->y - $innerBoundingBoxSize ) ) )
+        {
+            // Point is in inner bounding box -> everything is OK
+        }
+        elseif ( ( $newCenter->x < ( $center->x - $width ) ) ||
+                 ( $newCenter->x > ( $center->x + $width ) ) ||
+                 ( $newCenter->y < ( $center->y - $height ) ) ||
+                 ( $newCenter->y > ( $center->y + $height ) ) )
+        {
+            // Quick bounding box check
+            throw new ezcGraphReducementFailedException();
+        }
+        else
+        {
+            // Perform exact check
+            $distance = new ezcGraphVector(
+                $newCenter->x - $center->x,
+                $newCenter->y - $center->y
+            );
+
+            // Convert elipse to circle for correct angle calculation
+            $direction = clone $distance;
+            $direction->y *= ( $width / $height );
+            $angle = $direction->angle( new ezcGraphVector( 0, 1 ) );
+
+            $outerPoint = new ezcGraphVector(
+                sin( $angle ) * $width,
+                cos( $angle ) * $height
+            );
+
+            // Point is not in ellipse any more
+            if ( $distance->x > $outerPoint->x )
+            {
+                throw new ezcGraphReducementFailedException();
+            }
+        }
+
         // Use start spanning vector and its orthogonal vector to calculate 
         // new start point
         $newStartPoint = clone $oldStartPoint;