add image background option

word_cloud.php

@@ -15,12 +15,14 @@ class WordCloud {
   private $mask;
   private $table;
   private $image;
+  private $imagecolor;
 
-  public function __construct($width, $height, $font, $text=null, $vertical_freq = FrequencyTable::WORDS_MAINLY_HORIZONTAL) {
+  public function __construct($width, $height, $font, $text=null, $imagecolor=array( 0,0, 0, 127), $vertical_freq = FrequencyTable::WORDS_MAINLY_HORIZONTAL) {
     $this->width = $width;
     $this->height = $height;
     $this->font = $font;
-
+    $this->imagecolor = $imagecolor;
+
     $this->mask = new Mask();
     if(is_array($text)){
       $this->table = new FrequencyTable($font,'',$vertical_freq);//, $text);
@@ -40,7 +42,14 @@ public function __construct($width, $height, $font, $text=null, $vertical_freq =
     // $this->table->add_word('word4', 4);
     // $this->table->add_word('word5');
     // for($i = 6; $i <= 20; $i++) $this->table->add_word('word'.$i, $i % 5);
+
     $this->image = imagecreatetruecolor($width, $height);
+	//Set the flag to save full alpha channel information (as opposed to single-color transparency) when saving PNG images
+    imagesavealpha($this->image, true);
+	//behaves identically to imagecolorallocate() with the addition of the transparency parameter alpha
+    $trans_colour = imagecolorallocatealpha($this->image,  $imagecolor[0],$imagecolor[1], $imagecolor[2], $imagecolor[3]);
+    imagefill($this->image, 0, 0, $trans_colour);
+
   }
 
   public function get_image() {
@@ -84,6 +93,14 @@ public function render($palette) {
     list($x1, $y1, $x2, $y2) = $this->mask->get_bounding_box();
     $image2 = imagecreatetruecolor(abs($x2 - $x1), abs($y2 - $y1));
     imagecopy($image2 ,$this->image, 0, 0, $x1, $y1, abs($x2 - $x1), abs($y2 - $y1));
+
+    //Set the flag to save full alpha channel information (as opposed to single-color transparency) when saving PNG images
+    imagesavealpha($image2, true);
+    //behaves identically to imagecolorallocate() with the addition of the transparency parameter alpha
+    $trans_colour = imagecolorallocatealpha($image2, $this->imagecolor[0],$this->imagecolor[1], $this->imagecolor[2], $this->imagecolor[3]);
+    imagefill($image2, 0, 0, $trans_colour);
+
+
     imagedestroy($this->image);
     $this->image = $image2;