- Added image map support

# This changes all generated SVGs because each genereted element has an ID now

11 files changed, 304 insertions, 79 deletions

diff --git a/src/charts/line.php b/src/charts/line.php
index ebf86f9..6d6f381 100644
--- a/src/charts/line.php
+++ b/src/charts/line.php
@@ -108,7 +108,7 @@ class ezcGraphLineChart extends ezcGraphChart
         }
 
         // Display data
-        foreach ( $this->data as $data )
+        foreach ( $this->data as $datasetName => $data )
         {
             --$nr[$data->displayType->default];
             switch ( $data->displayType->default )
@@ -140,6 +140,7 @@ class ezcGraphLineChart extends ezcGraphChart
 
                         $renderer->drawDataLine(
                             $boundings,
+                            new ezcGraphContext( $datasetName, $key ),
                             $data->color->default,
                             ( $lastPoint === false ? $point : $lastPoint ),
                             $point,
@@ -173,6 +174,7 @@ class ezcGraphLineChart extends ezcGraphChart
 
                         $renderer->drawBar(
                             $boundings,
+                            new ezcGraphContext( $datasetName, $key ),
                             $data->color->default,
                             $this->elements['xAxis']->axisLabelRenderer->modifyChartDataPosition( 
                                 $this->elements['yAxis']->axisLabelRenderer->modifyChartDataPosition(
diff --git a/src/charts/pie.php b/src/charts/pie.php
index 5f4258a..b21401e 100644
--- a/src/charts/pie.php
+++ b/src/charts/pie.php
@@ -35,6 +35,7 @@ class ezcGraphPieChart extends ezcGraphChart
     {
         // Only draw the first (and only) dataset
         $dataset = $this->data->rewind();
+        $datasetName = $this->data->key();
 
         $this->driver->options->font = $this->options->font;
 
@@ -53,6 +54,7 @@ class ezcGraphPieChart extends ezcGraphChart
                 case ezcGraph::PIE:
                     $renderer->drawPieSegment(
                         $boundings,
+                        new ezcGraphContext( $datasetName, $label ),
                         $dataset->color[$label],
                         $angle,
                         $angle += $value / $sum * 360,
diff --git a/src/driver/gd.php b/src/driver/gd.php
index bf9249b..1e30e81 100644
--- a/src/driver/gd.php
+++ b/src/driver/gd.php
@@ -170,6 +170,8 @@ class ezcGraphGdDriver extends ezcGraphDriver
         {
             imagepolygon( $image, $pointArray, $pointCount, $drawColor );
         }
+
+        return $points;
     }
     
     /**
@@ -204,6 +206,8 @@ class ezcGraphGdDriver extends ezcGraphDriver
             $this->image, 
             $this->options->supersampling
         );
+
+        return array();
     }
     
     /**
@@ -415,6 +419,13 @@ class ezcGraphGdDriver extends ezcGraphDriver
         {
             throw new ezcGraphFontRenderingException( $string, $this->options->font->minFontSize, $width, $height );
         }
+
+        return array(
+            clone $position,
+            new ezcGraphCoordinate( $position->x + $width, $position->y ),
+            new ezcGraphCoordinate( $position->x + $width, $position->y + $height ),
+            new ezcGraphCoordinate( $position->x, $position->y + $height ),
+        );
     }
     
     protected function drawAllTexts()
@@ -546,6 +557,26 @@ class ezcGraphGdDriver extends ezcGraphDriver
                 IMG_ARC_PIE | IMG_ARC_NOFILL | IMG_ARC_EDGED
             );
         }
+
+        // Create polygon array to return
+        $polygonArray = array( $center );
+        for ( $angle = $startAngle; $angle < $endAngle; $angle += $this->options->imageMapResolution )
+        {
+            $polygonArray[] = new ezcGraphCoordinate(
+                $center->x + 
+                    ( ( cos( deg2rad( $angle ) ) * $width ) / 2 ),
+                $center->y + 
+                    ( ( sin( deg2rad( $angle ) ) * $height ) / 2 )
+            );
+        }
+        $polygonArray[] = new ezcGraphCoordinate(
+            $center->x + 
+                ( ( cos( deg2rad( $endAngle ) ) * $width ) / 2 ),
+            $center->y + 
+                ( ( sin( deg2rad( $endAngle ) ) * $height ) / 2 )
+        );
+
+        return $polygonArray;
     }
 
     /**
@@ -680,6 +711,42 @@ class ezcGraphGdDriver extends ezcGraphDriver
                 IMG_ARC_PIE | IMG_ARC_NOFILL
             );
         }
+
+        // Create polygon array to return
+        $polygonArray = array();
+        for ( $angle = $startAngle; $angle < $endAngle; $angle += $this->options->imageMapResolution )
+        {
+            $polygonArray[] = new ezcGraphCoordinate(
+                $center->x + 
+                    ( ( cos( deg2rad( $angle ) ) * $width ) / 2 ),
+                $center->y + 
+                    ( ( sin( deg2rad( $angle ) ) * $height ) / 2 )
+            );
+        }
+        $polygonArray[] = new ezcGraphCoordinate(
+            $center->x + 
+                ( ( cos( deg2rad( $endAngle ) ) * $width ) / 2 ),
+            $center->y + 
+                ( ( sin( deg2rad( $endAngle ) ) * $height ) / 2 )
+        );
+
+        for ( $angle = $endAngle; $angle > $startAngle; $angle -= $this->options->imageMapResolution )
+        {
+            $polygonArray[] = new ezcGraphCoordinate(
+                $center->x + 
+                    ( ( cos( deg2rad( $angle ) ) * $width ) / 2 ) + $size,
+                $center->y + 
+                    ( ( sin( deg2rad( $angle ) ) * $height ) / 2 )
+            );
+        }
+        $polygonArray[] = new ezcGraphCoordinate(
+            $center->x + 
+                ( ( cos( deg2rad( $startAngle ) ) * $width ) / 2 ) + $size,
+            $center->y + 
+                ( ( sin( deg2rad( $startAngle ) ) * $height ) / 2 )
+        );
+
+        return $polygonArray;
     }
     
     /**
@@ -721,6 +788,19 @@ class ezcGraphGdDriver extends ezcGraphDriver
                 $drawColor 
             );
         }
+
+        $polygonArray = array();
+        for ( $angle = 0; $angle < 360; $angle += $this->options->imageMapResolution )
+        {
+            $polygonArray[] = new ezcGraphCoordinate(
+                $center->x + 
+                    ( ( cos( deg2rad( $angle ) ) * $width ) / 2 ),
+                $center->y + 
+                    ( ( sin( deg2rad( $angle ) ) * $height ) / 2 )
+            );
+        }
+
+        return $polygonArray;
     }
     
     /**
@@ -740,6 +820,13 @@ class ezcGraphGdDriver extends ezcGraphDriver
             'width' => $width,
             'height' => $height,
         );
+
+        return array(
+            $position,
+            new ezcGraphCoordinate( $position->x + $width, $position->y ),
+            new ezcGraphCoordinate( $position->x + $width, $position->y + $height ),
+            new ezcGraphCoordinate( $position->x, $position->y + $height ),
+        );
     }
 
     /**
diff --git a/src/driver/svg.php b/src/driver/svg.php
index 0a6bd28..b7de230 100644
--- a/src/driver/svg.php
+++ b/src/driver/svg.php
@@ -55,6 +55,13 @@ class ezcGraphSvgDriver extends ezcGraphDriver
      */
     protected $drawnGradients = array();
 
+    /**
+     * Numeric unique element id
+     * 
+     * @var int
+     */
+    protected $elementID = 0;
+
     public function __construct( array $options = array() )
     {
         $this->options = new ezcGraphSvgDriverOptions( $options );
@@ -297,8 +304,10 @@ class ezcGraphSvgDriver extends ezcGraphDriver
             'style',
             $this->getStyle( $color, $filled, $thickness )
         );
-		
+        $path->setAttribute( 'id', $id = ( 'ezcGraphPolygon_' . ++$this->elementID ) );
 		$this->elements->appendChild( $path );
+
+        return $id;
     }
     
     /**
@@ -327,7 +336,10 @@ class ezcGraphSvgDriver extends ezcGraphDriver
             $this->getStyle( $color, false, $thickness )
         );
 
+        $path->setAttribute( 'id', $id = ( 'ezcGraphLine_' . ++$this->elementID ) );
         $this->elements->appendChild( $path );
+
+        return $id;
     }
 
     protected function testFitStringInTextBox( $string, ezcGraphCoordinate $position, $width, $height, $size )
@@ -408,19 +420,18 @@ class ezcGraphSvgDriver extends ezcGraphDriver
             }
         }
 
-        if ( is_array( $result ) )
-        {
-            $this->options->font->minimalUsedFont = $size;
-
-            $this->strings[] = array(
-                'text' => $result,
-                'position' => $position,
-                'width' => $width,
-                'height' => $height,
-                'align' => $align,
-                'options' => $this->options->font,
-            );
-        }
+        $this->options->font->minimalUsedFont = $size;
+        $this->strings[] = array(
+            'text' => $result,
+            'id' => $id = ( 'ezcGraphTextBox_' . ++$this->elementID ),
+            'position' => $position,
+            'width' => $width,
+            'height' => $height,
+            'align' => $align,
+            'options' => $this->options->font,
+        );
+
+        return $id;
     }
 
     protected function drawAllTexts()
@@ -476,6 +487,7 @@ class ezcGraphSvgDriver extends ezcGraphDriver
                 }
 
                 $textNode = $this->dom->createElement( 'text', $string );
+                $textNode->setAttribute( 'id', $text['id'] );
                 $textNode->setAttribute( 'x', $position->x + $this->options->graphOffset->x );
                 $textNode->setAttribute( 'text-length', ( $size * strlen( $string ) * $this->options->assumedCharacterWidth ) . 'px' );
                 $textNode->setAttribute( 'y', $position->y + $this->options->graphOffset->y );
@@ -551,7 +563,10 @@ class ezcGraphSvgDriver extends ezcGraphDriver
             $this->getStyle( $color, $filled, 1 )
         );
         
+        $arc->setAttribute( 'id', $id = ( 'ezcGraphCircleSector_' . ++$this->elementID ) );
         $this->elements->appendChild( $arc );
+        
+        return $id;
     }
 
     /**
@@ -646,6 +661,7 @@ class ezcGraphSvgDriver extends ezcGraphDriver
             $this->getStyle( $color, $filled )
         );
 
+        $arc->setAttribute( 'id', $id = ( 'ezcGraphCircularArc_' . ++$this->elementID ) );
         $this->elements->appendChild( $arc );
 
         if ( ( $this->options->shadeCircularArc !== false ) &&
@@ -692,6 +708,8 @@ class ezcGraphSvgDriver extends ezcGraphDriver
 
             $this->elements->appendChild( $arc );
         }
+
+        return $id;
     }
 
     /**
@@ -720,7 +738,10 @@ class ezcGraphSvgDriver extends ezcGraphDriver
             $this->getStyle( $color, $filled, 1 )
         );
         
+        $ellipse->setAttribute( 'id', $id = ( 'ezcGraphCircle_' . ++$this->elementID ) );
         $this->elements->appendChild( $ellipse );
+
+        return $id;
     }
 
     /**
@@ -753,6 +774,9 @@ class ezcGraphSvgDriver extends ezcGraphDriver
         );
 
         $this->elements->appendChild( $image );
+        $image->setAttribute( 'id', $id = ( 'ezcGraphImage_' . ++$this->elementID ) );
+
+        return $id;
     }
 
     /**
diff --git a/src/graph_autoload.php b/src/graph_autoload.php
index f415aa6..448a3d9 100644
--- a/src/graph_autoload.php
+++ b/src/graph_autoload.php
@@ -96,6 +96,7 @@ return array(
     'ezcGraphBoundings'                         => 'Graph/math/boundings.php',
 
     'ezcGraphCoordinate'                        => 'Graph/structs/coordinate.php',
+    'ezcGraphContext'                           => 'Graph/structs/context.php',
 );
 
 ?>
diff --git a/src/interfaces/driver.php b/src/interfaces/driver.php
index b7045f0..a763f91 100644
--- a/src/interfaces/driver.php
+++ b/src/interfaces/driver.php
@@ -69,7 +69,7 @@ abstract class ezcGraphDriver
             case 'options':
                 return $this->options;
             default:
-                return parent::__get( $propertyName );
+                throw new ezcBasePropertyNotFoundException( $propertyName );
         }
     }
 
diff --git a/src/interfaces/renderer.php b/src/interfaces/renderer.php
index 80fdc5d..84907e0 100644
--- a/src/interfaces/renderer.php
+++ b/src/interfaces/renderer.php
@@ -23,11 +23,23 @@ abstract class ezcGraphRenderer
     
     protected $yAxisSpace = false;
 
+    protected $elements = array();
+
     public function setDriver( ezcGraphDriver $driver )
     {
         $this->driver = $driver;
     }
 
+    protected function addElementReference( ezcGraphContext $context, $reference )
+    {
+        $this->elements['data'][$context->dataset][$context->datapoint][] = $reference;
+    }
+
+    public function getElementReferences()
+    {
+        return $this->elements;
+    }
+
     /**
      * __get 
      * 
@@ -44,6 +56,8 @@ abstract class ezcGraphRenderer
             case 'xAxisSpace':
             case 'yAxisSpace':
                 return $this->$propertyName;
+            case 'elements':
+                return $this->elements;
             default:
                 throw new ezcBasePropertyNotFoundException( $propertyName );
         }
@@ -55,6 +69,7 @@ abstract class ezcGraphRenderer
      * Draws a single pie segment
      * 
      * @param ezcGraphBoundings $boundings Chart boundings
+     * @param ezcGraphContext $context Context of call
      * @param ezcGraphColor $color Color of pie segment
      * @param float $startAngle Start angle
      * @param float $endAngle End angle
@@ -64,6 +79,7 @@ abstract class ezcGraphRenderer
      */
     abstract public function drawPieSegment(
         ezcGraphBoundings $boundings,
+        ezcGraphContext $context,
         ezcGraphColor $color,
         $startAngle = .0,
         $endAngle = 360.,
@@ -77,6 +93,7 @@ abstract class ezcGraphRenderer
      * Draws a bar as a data element in a line chart
      * 
      * @param ezcGraphBoundings $boundings Chart boundings
+     * @param ezcGraphContext $context Context of call
      * @param ezcGraphColor $color Color of line
      * @param ezcGraphCoordinate $position Position of data point
      * @param float $stepSize Space which can be used for bars
@@ -88,6 +105,7 @@ abstract class ezcGraphRenderer
      */
     abstract public function drawBar(
         ezcGraphBoundings $boundings,
+        ezcGraphContext $context,
         ezcGraphColor $color,
         ezcGraphCoordinate $position,
         $stepSize,
@@ -103,6 +121,7 @@ abstract class ezcGraphRenderer
      * Draws a line as a data element in a line chart
      * 
      * @param ezcGraphBoundings $boundings Chart boundings
+     * @param ezcGraphContext $context Context of call
      * @param ezcGraphColor $color Color of line
      * @param ezcGraphCoordinate $start Starting point
      * @param ezcGraphCoordinate $end Ending point
@@ -117,6 +136,7 @@ abstract class ezcGraphRenderer
      */
     abstract public function drawDataLine(
         ezcGraphBoundings $boundings,
+        ezcGraphContext $context,
         ezcGraphColor $color,
         ezcGraphCoordinate $start,
         ezcGraphCoordinate $end,
@@ -268,7 +288,7 @@ abstract class ezcGraphRenderer
         switch ( $symbol )
         {
             case ezcGraph::NO_SYMBOL:
-                $this->driver->drawPolygon(
+                $return = $this->driver->drawPolygon(
                     array(
                         new ezcGraphCoordinate( $boundings->x0, $boundings->y0 ),
                         new ezcGraphCoordinate( $boundings->x1, $boundings->y0 ),
@@ -310,9 +330,9 @@ abstract class ezcGraphRenderer
                         true
                     );
                 }
-                break;
+                return $return;
             case ezcGraph::DIAMOND:
-                $this->driver->drawPolygon(
+                $return = $this->driver->drawPolygon(
                     array(
                         new ezcGraphCoordinate( 
                             $boundings->x0 + ( $boundings->x1 - $boundings->x0 ) / 2, 
@@ -372,9 +392,9 @@ abstract class ezcGraphRenderer
                         true
                     );
                 }
-                break;
+                return $return;
             case ezcGraph::BULLET:
-                $this->driver->drawCircle(
+                $return = $this->driver->drawCircle(
                     new ezcGraphCoordinate( 
                         $boundings->x0 + ( $boundings->x1 - $boundings->x0 ) / 2, 
                         $boundings->y0 + ( $boundings->y1 - $boundings->y0 ) / 2
@@ -410,9 +430,9 @@ abstract class ezcGraphRenderer
                         true
                     );
                 }
-                break;
+                return $return;
             case ezcGraph::CIRCLE:
-                $this->driver->drawCircle(
+                return $this->driver->drawCircle(
                     new ezcGraphCoordinate( 
                         $boundings->x0 + ( $boundings->x1 - $boundings->x0 ) / 2, 
                         $boundings->y0 + ( $boundings->y1 - $boundings->y0 ) / 2
@@ -422,7 +442,6 @@ abstract class ezcGraphRenderer
                     $color,
                     false
                 );
-                break;
         }
     }
 
diff --git a/src/options/gd_driver.php b/src/options/gd_driver.php
index 2faddd7..0037892 100644
--- a/src/options/gd_driver.php
+++ b/src/options/gd_driver.php
@@ -23,6 +23,9 @@
  *           Function used to resample / resize images
  * @property bool $forceNativeTTF
  *           Force use of native ttf functions instead of free type 2
+ * @property float $imageMapResolution
+ *           Degree step used to interpolate round image primitives by 
+ *           polygons for image maps
  *
  * @package Graph
  */
@@ -44,6 +47,7 @@ class ezcGraphGdDriverOptions extends ezcGraphDriverOptions
         $this->properties['background'] = false;
         $this->properties['resampleFunction'] = 'imagecopyresampled';
         $this->properties['forceNativeTTF'] = false;
+        $this->properties['imageMapResolution'] = 10;
 
         parent::__construct( $options );
     }
@@ -101,6 +105,9 @@ class ezcGraphGdDriverOptions extends ezcGraphDriverOptions
             case 'forceNativeTTF':
                 $this->properties['forceNativeTTF'] = (bool) $propertyValue;
                 break;
+            case 'imageMapResolution':
+                $this->properties['imageMapResolution'] = max( 1, (int) $propertyValue );
+                break;
             default:
                 parent::__set( $propertyName, $propertyValue );
                 break;
diff --git a/src/renderer/2d.php b/src/renderer/2d.php
index 677e2ac..5099e61 100644
--- a/src/renderer/2d.php
+++ b/src/renderer/2d.php
@@ -51,6 +51,7 @@ class ezcGraphRenderer2d extends ezcGraphRenderer
      * Draws a single pie segment
      * 
      * @param ezcGraphBoundings $boundings Chart boundings
+     * @param ezcGraphContext $context Context of call
      * @param ezcGraphColor $color Color of pie segment
      * @param float $startAngle Start angle
      * @param float $endAngle End angle
@@ -60,6 +61,7 @@ class ezcGraphRenderer2d extends ezcGraphRenderer
      */
     public function drawPieSegment(
         ezcGraphBoundings $boundings,
+        ezcGraphContext $context,
         ezcGraphColor $color,
         $startAngle = .0,
         $endAngle = 360.,
@@ -90,14 +92,17 @@ class ezcGraphRenderer2d extends ezcGraphRenderer
         }
 
         // Draw circle sector
-        $this->driver->drawCircleSector(
-            $center,
-            $radius * 2,
-            $radius * 2,
-            $startAngle + $this->options->pieChartOffset,
-            $endAngle + $this->options->pieChartOffset,
-            $color,
-            true
+        $this->addElementReference( 
+            $context,
+            $this->driver->drawCircleSector(
+                $center,
+                $radius * 2,
+                $radius * 2,
+                $startAngle + $this->options->pieChartOffset,
+                $endAngle + $this->options->pieChartOffset,
+                $color,
+                true
+            )
         );
 
         $darkenedColor = $color->darken( .5 );
@@ -127,7 +132,8 @@ class ezcGraphRenderer2d extends ezcGraphRenderer
                     cos( deg2rad( $middle ) ) * $radius * 2 / 3 + $center->x,
                     sin( deg2rad( $middle ) ) * $radius * 2 / 3 + $center->y
                 ),
-                $label
+                $label,
+                $context
             );
         }
 
@@ -236,15 +242,18 @@ class ezcGraphRenderer2d extends ezcGraphRenderer
                     );
                 }
 
-                $this->driver->drawTextBox(
-                    $label[1],
-                    new ezcGraphCoordinate(
-                        ( !$side ? $boundings->x0 : $labelPosition->x + $symbolSize ),
-                        $minHeight
-                    ),
-                    ( !$side ? $labelPosition->x - $boundings->x0 - $symbolSize : $boundings->x1 - $labelPosition->x - $symbolSize ),
-                    $labelHeight,
-                    ( !$side ? ezcGraph::RIGHT : ezcGraph::LEFT ) | ezcGraph::MIDDLE
+                $this->addElementReference( 
+                    $label[2],
+                    $this->driver->drawTextBox(
+                        $label[1],
+                        new ezcGraphCoordinate(
+                            ( !$side ? $boundings->x0 : $labelPosition->x + $symbolSize ),
+                            $minHeight
+                        ),
+                        ( !$side ? $labelPosition->x - $boundings->x0 - $symbolSize : $boundings->x1 - $labelPosition->x - $symbolSize ),
+                        $labelHeight,
+                        ( !$side ? ezcGraph::RIGHT : ezcGraph::LEFT ) | ezcGraph::MIDDLE
+                    )
                 );
 
                 // Add used space to minHeight
@@ -257,10 +266,13 @@ class ezcGraphRenderer2d extends ezcGraphRenderer
     {
         foreach ( $this->linePostSymbols as $symbol )
         {
-            $this->drawSymbol(
-                $symbol['boundings'],
-                $symbol['color'],
-                $symbol['symbol']
+            $this->addElementReference(
+                $symbol['context'],
+                $this->drawSymbol(
+                    $symbol['boundings'],
+                    $symbol['color'],
+                    $symbol['symbol']
+                )
             );
         }
     }
@@ -271,6 +283,7 @@ class ezcGraphRenderer2d extends ezcGraphRenderer
      * Draws a bar as a data element in a line chart
      * 
      * @param ezcGraphBoundings $boundings Chart boundings
+     * @param ezcGraphContext $context Context of call
      * @param ezcGraphColor $color Color of line
      * @param ezcGraphCoordinate $position Position of data point
      * @param float $stepSize Space which can be used for bars
@@ -282,6 +295,7 @@ class ezcGraphRenderer2d extends ezcGraphRenderer
      */
     public function drawBar(
         ezcGraphBoundings $boundings,
+        ezcGraphContext $context,
         ezcGraphColor $color,
         ezcGraphCoordinate $position,
         $stepSize,
@@ -315,10 +329,13 @@ class ezcGraphRenderer2d extends ezcGraphRenderer
             ),
         );
 
-        $this->driver->drawPolygon(
-            $barPointArray,
-            $color,
-            true
+        $this->addElementReference(
+            $context,
+            $this->driver->drawPolygon(
+                $barPointArray,
+                $color,
+                true
+            )
         );
 
         if ( $this->options->dataBorder > 0 )
@@ -339,6 +356,7 @@ class ezcGraphRenderer2d extends ezcGraphRenderer
      * Draws a line as a data element in a line chart
      * 
      * @param ezcGraphBoundings $boundings Chart boundings
+     * @param ezcGraphContext $context Context of call
      * @param ezcGraphColor $color Color of line
      * @param ezcGraphCoordinate $start Starting point
      * @param ezcGraphCoordinate $end Ending point
@@ -353,6 +371,7 @@ class ezcGraphRenderer2d extends ezcGraphRenderer
      */
     public function drawDataLine(
         ezcGraphBoundings $boundings,
+        ezcGraphContext $context,
         ezcGraphColor $color,
         ezcGraphCoordinate $start,
         ezcGraphCoordinate $end,
@@ -481,6 +500,7 @@ class ezcGraphRenderer2d extends ezcGraphRenderer
                     $boundings->y0 + ( $boundings->y1 - $boundings->y0 ) * $end->y + $this->options->symbolSize / 2
                 ),
                 'color' => $symbolColor,
+                'context' => $context,
                 'symbol' => $symbol,
             );
         }
@@ -527,7 +547,7 @@ class ezcGraphRenderer2d extends ezcGraphRenderer
         $labelPosition = new ezcGraphCoordinate( $boundings->x0, $boundings->y0 );
         foreach ( $labels as $label )
         {
-            $this->drawSymbol(
+            $this->elements['legend'][$label['label']]['symbol'] = $this->drawSymbol(
                 new ezcGraphBoundings(
                     $labelPosition->x + $legend->padding,
                     $labelPosition->y + $legend->padding,
@@ -538,7 +558,7 @@ class ezcGraphRenderer2d extends ezcGraphRenderer
                 $label['symbol']
             );
 
-            $this->driver->drawTextBox(
+            $this->elements['legend'][$label['label']]['text'] = $this->driver->drawTextBox(
                 $label['label'],
                 new ezcGraphCoordinate(
                     $labelPosition->x + 2 * $legend->padding + $symbolSize,
diff --git a/src/renderer/3d.php b/src/renderer/3d.php
index 610d34e..b1ccbe5 100644
--- a/src/renderer/3d.php
+++ b/src/renderer/3d.php
@@ -73,6 +73,7 @@ class ezcGraphRenderer3d extends ezcGraphRenderer
      * Draws a single pie segment
      * 
      * @param ezcGraphBoundings $boundings Chart boundings
+     * @param ezcGraphContext $context Context of call
      * @param ezcGraphColor $color Color of pie segment
      * @param float $startAngle Start angle
      * @param float $endAngle End angle
@@ -82,6 +83,7 @@ class ezcGraphRenderer3d extends ezcGraphRenderer
      */
     public function drawPieSegment(
         ezcGraphBoundings $boundings,
+        ezcGraphContext $context,
         ezcGraphColor $color,
         $startAngle = .0,
         $endAngle = 360.,
@@ -119,6 +121,7 @@ class ezcGraphRenderer3d extends ezcGraphRenderer
         // Add circle sector to queue
         $this->circleSectors[] = array(
             'center' =>     $center,
+            'context' =>    $context,
             'width' =>      $radius * 2,
             'height' =>     $radius * 2 * $this->options->pieChartRotation - $this->options->pieChartHeight,
             'start' =>      $startAngle,
@@ -139,7 +142,8 @@ class ezcGraphRenderer3d extends ezcGraphRenderer
             // y position
             $this->pieSegmentLabels[(int) ($pieSegmentCenter->x > $center->x)][$pieSegmentCenter->y] = array(
                 clone $pieSegmentCenter,
-                $label
+                $label,
+                $context,
             );
         }
 
@@ -248,15 +252,17 @@ class ezcGraphRenderer3d extends ezcGraphRenderer
                     );
                 }
 
-                $this->driver->drawTextBox(
-                    $label[1],
-                    new ezcGraphCoordinate(
-                        ( !$side ? $boundings->x0 : $labelPosition->x + $symbolSize ),
-                        $minHeight
-                    ),
-                    ( !$side ? $labelPosition->x - $boundings->x0 - $symbolSize : $boundings->x1 - $labelPosition->x - $symbolSize ),
-                    $labelHeight,
-                    ( !$side ? ezcGraph::RIGHT : ezcGraph::LEFT ) | ezcGraph::MIDDLE
+                $this->addElementReference( $label[2], 
+                    $this->driver->drawTextBox(
+                        $label[1],
+                        new ezcGraphCoordinate(
+                            ( !$side ? $boundings->x0 : $labelPosition->x + $symbolSize ),
+                            $minHeight
+                        ),
+                        ( !$side ? $labelPosition->x - $boundings->x0 - $symbolSize : $boundings->x1 - $labelPosition->x - $symbolSize ),
+                        $labelHeight,
+                        ( !$side ? ezcGraph::RIGHT : ezcGraph::LEFT ) | ezcGraph::MIDDLE
+                    )
                 );
 
                 // Add used space to minHeight
@@ -453,14 +459,16 @@ class ezcGraphRenderer3d extends ezcGraphRenderer
         // Draw circle sector for front
         foreach ( $this->circleSectors as $circleSector )
         {
-            $this->driver->drawCircleSector(
-                $circleSector['center'],
-                $circleSector['width'],
-                $circleSector['height'],
-                $circleSector['start'],
-                $circleSector['end'],
-                $circleSector['color'],
-                true
+            $this->addElementReference( $circleSector['context'],
+                $this->driver->drawCircleSector(
+                    $circleSector['center'],
+                    $circleSector['width'],
+                    $circleSector['height'],
+                    $circleSector['start'],
+                    $circleSector['end'],
+                    $circleSector['color'],
+                    true
+                )
             );
 
             if ( $this->options->pieChartGleam !== false )
@@ -541,10 +549,12 @@ class ezcGraphRenderer3d extends ezcGraphRenderer
     {
         foreach ( $this->linePostSymbols as $symbol )
         {
-            $this->drawSymbol(
-                $symbol['boundings'],
-                $symbol['color'],
-                $symbol['symbol']
+            $this->addElementReference( $symbol['context'],
+                $this->drawSymbol(
+                    $symbol['boundings'],
+                    $symbol['color'],
+                    $symbol['symbol']
+                )
             );
         }
     }
@@ -555,6 +565,7 @@ class ezcGraphRenderer3d extends ezcGraphRenderer
      * Draws a bar as a data element in a line chart
      * 
      * @param ezcGraphBoundings $boundings Chart boundings
+     * @param ezcGraphContext $context Context of call
      * @param ezcGraphColor $color Color of line
      * @param ezcGraphCoordinate $position Position of data point
      * @param float $stepSize Space which can be used for bars
@@ -566,6 +577,7 @@ class ezcGraphRenderer3d extends ezcGraphRenderer
      */
     public function drawBar(
         ezcGraphBoundings $boundings,
+        ezcGraphContext $context,
         ezcGraphColor $color,
         ezcGraphCoordinate $position,
         $stepSize,
@@ -610,6 +622,7 @@ class ezcGraphRenderer3d extends ezcGraphRenderer
                 $this->barPostProcessing[] = array(
                     'index' => $barPolygonArray[2]->x,
                     'method' => 'drawPolygon',
+                    'context' => $context,
                     'parameters' => array(
                         array(
                             $this->get3dCoordinate( $barPolygonArray[2], $startDepth ),
@@ -626,6 +639,7 @@ class ezcGraphRenderer3d extends ezcGraphRenderer
                 $this->barPostProcessing[] = array(
                     'index' => $barPolygonArray[1]->x,
                     'method' => 'drawPolygon',
+                    'context' => $context,
                     'parameters' => array(
                         ( $barPolygonArray[1]->y < $barPolygonArray[3]->y
                         ?   array(
@@ -652,6 +666,7 @@ class ezcGraphRenderer3d extends ezcGraphRenderer
                     $this->barPostProcessing[] = array(
                         'index' => $barPolygonArray[1]->x + 1,
                         'method' => 'drawPolygon',
+                        'context' => $context,
                         'parameters' => array(
                             ( $barPolygonArray[1]->y < $barPolygonArray[3]->y
                             ?   array(
@@ -688,6 +703,7 @@ class ezcGraphRenderer3d extends ezcGraphRenderer
                 $this->barPostProcessing[] = array(
                     'index' => $barPolygonArray[1]->x,
                     'method' => 'drawPolygon',
+                    'context' => $context,
                     'parameters' => array(
                         array(
                             $this->get3dCoordinate( $barPolygonArray[0], $startDepth ),
@@ -706,6 +722,7 @@ class ezcGraphRenderer3d extends ezcGraphRenderer
                     $this->barPostProcessing[] = array(
                         'index' => $barPolygonArray[1]->x + 1,
                         'method' => 'drawPolygon',
+                        'context' => $context,
                         'parameters' => array(
                             array(
                                 $this->get3dCoordinate( $barPolygonArray[0], $startDepth ),
@@ -745,6 +762,7 @@ class ezcGraphRenderer3d extends ezcGraphRenderer
                 $this->barPostProcessing[] = array(
                     'index' => $barCoordinateArray['x'][0],
                     'method' => 'drawPolygon',
+                    'context' => $context,
                     'parameters' => array(
                         array(
                             $this->get3dCoordinate( new ezcGraphCoordinate( $barCoordinateArray['x'][0], $barCoordinateArray['y'][0] ), $midDepth ),
@@ -761,6 +779,7 @@ class ezcGraphRenderer3d extends ezcGraphRenderer
                 $this->barPostProcessing[] = array(
                     'index' => $barCoordinateArray['x'][1],
                     'method' => 'drawPolygon',
+                    'context' => $context,
                     'parameters' => array(
                         array(
                             $this->get3dCoordinate( new ezcGraphCoordinate( $barCoordinateArray['x'][2], $barCoordinateArray['y'][0] ), $midDepth ),
@@ -782,6 +801,7 @@ class ezcGraphRenderer3d extends ezcGraphRenderer
                 $this->barPostProcessing[] = array(
                     'index' => $barCoordinateArray['x'][0],
                     'method' => 'drawPolygon',
+                    'context' => $context,
                     'parameters' => array(
                         array(
                             $this->get3dCoordinate( new ezcGraphCoordinate( $barCoordinateArray['x'][1], $topLocation ), $startDepth ),
@@ -800,6 +820,7 @@ class ezcGraphRenderer3d extends ezcGraphRenderer
                     $this->barPostProcessing[] = array(
                         'index' => $barCoordinateArray['x'][0] + 1,
                         'method' => 'drawPolygon',
+                        'context' => $context,
                         'parameters' => array(
                             array(
                                 $this->get3dCoordinate( new ezcGraphCoordinate( $barCoordinateArray['x'][1], $topLocation ), $startDepth ),
@@ -840,6 +861,7 @@ class ezcGraphRenderer3d extends ezcGraphRenderer
                 $this->barPostProcessing[] = array(
                     'index' => $barCenterBottom->x,
                     'method' => 'drawCircularArc',
+                    'context' => $context,
                     'parameters' => array(
                         $this->get3dCoordinate( $barCenterTop, $midDepth ),
                         $barWidth,
@@ -854,6 +876,7 @@ class ezcGraphRenderer3d extends ezcGraphRenderer
                 $this->barPostProcessing[] = array(
                     'index' => $barCenterBottom->x + 1,
                     'method' => 'drawCircle',
+                    'context' => $context,
                     'parameters' => array(
                         $top = $this->get3dCoordinate( $barCenterTop, $midDepth ),
                         $barWidth,
@@ -901,9 +924,11 @@ class ezcGraphRenderer3d extends ezcGraphRenderer
 
         foreach ( $this->barPostProcessing as $bar )
         {
-            call_user_func_array(
-                array( $this->driver, $bar['method'] ),
-                $bar['parameters']
+            $this->addElementReference( $bar['context'],
+                call_user_func_array(
+                    array( $this->driver, $bar['method'] ),
+                    $bar['parameters']
+                )
             );
         }
     }
@@ -914,6 +939,7 @@ class ezcGraphRenderer3d extends ezcGraphRenderer
      * Draws a line as a data element in a line chart
      * 
      * @param ezcGraphBoundings $boundings Chart boundings
+     * @param ezcGraphContext $context Context of call
      * @param ezcGraphColor $color Color of line
      * @param ezcGraphCoordinate $start Starting point
      * @param ezcGraphCoordinate $end Ending point
@@ -928,6 +954,7 @@ class ezcGraphRenderer3d extends ezcGraphRenderer
      */
     public function drawDataLine(
         ezcGraphBoundings $boundings,
+        ezcGraphContext $context,
         ezcGraphColor $color,
         ezcGraphCoordinate $start,
         ezcGraphCoordinate $end,
@@ -1092,6 +1119,7 @@ class ezcGraphRenderer3d extends ezcGraphRenderer
                     $linePolygonPoints[2]->y + $this->options->symbolSize / 2
                 ),
                 'color' => $symbolColor,
+                'context' => $context,
                 'symbol' => $symbol,
             );
         }
@@ -1138,7 +1166,7 @@ class ezcGraphRenderer3d extends ezcGraphRenderer
         $labelPosition = new ezcGraphCoordinate( $boundings->x0, $boundings->y0 );
         foreach ( $labels as $label )
         {
-            $this->drawSymbol(
+            $this->elements['legend'][$label['label']]['symbol'] = $this->drawSymbol(
                 new ezcGraphBoundings(
                     $labelPosition->x + $legend->padding,
                     $labelPosition->y + $legend->padding,
@@ -1149,7 +1177,7 @@ class ezcGraphRenderer3d extends ezcGraphRenderer
                 $label['symbol']
             );
 
-            $this->driver->drawTextBox(
+            $this->elements['legend'][$label['label']]['text'] = $this->driver->drawTextBox(
                 $label['label'],
                 new ezcGraphCoordinate(
                     $labelPosition->x + 2 * $legend->padding + $symbolSize,
diff --git a/src/structs/context.php b/src/structs/context.php
new file mode 100644
index 0000000..351031f
--- /dev/null
+++ b/src/structs/context.php
@@ -0,0 +1,35 @@
+<?php
+
+class ezcGraphContext
+{
+    public $dataset = false;
+
+    public $datapoint = false;
+    
+    /**
+     * Empty constructor
+     */
+    public function __construct( $dataset = false, $datapoint = false )
+    {
+        $this->dataset = $dataset;
+        $this->datapoint = $datapoint;
+    }
+
+    /**
+     * Throws a BasePropertyNotFound exception.
+     */
+    public function __set( $name, $value )
+    {
+        throw new ezcBasePropertyNotFoundException( $name );
+    }
+
+    /**
+     * Throws a BasePropertyNotFound exception.
+     */
+    public function __get( $name )
+    {
+        throw new ezcBasePropertyNotFoundException( $name );
+    }
+}
+
+?>