imagecolorallocatealpha() function in PHP

The imagecolorallocatealpha() function allocates a color for an image.

Syntax

imagecolorallocatealpha ( img, red, green, blue, alpha )

Parameters

• img: Image resource created with imagecreatetruecolor().

• red: Red color component

• green: Green color component

• blue: Blue color component

• alpha: The transparency of image, with 0 indicating completely opaque, whereas 127 indicating completely transparent.

Return

The imagecolorallocatealpha() function returns a color identifier or FALSE if the allocation failed.

Example

The following is an example:

<?php
   $img = imagecreatetruecolor(520, 350);
   $bgcolor = imagecolorallocate($img, 50, 10, 255);
   imagefill($img, 0, 0, $bgcolor);
   $one = imagecolorallocatealpha($img, 50, 255, 0, 70);
   $two = imagecolorallocatealpha($img, 255, 0, 255, 50);
   $three = imagecolorallocatealpha($img, 150, 255, 0, 60);
   $four = imagecolorallocatealpha($img, 200, 0, 255, 90);
   imagefilledellipse($img, 200, 150, 150, 150, $one);
   imagefilledellipse($img, 220, 150, 150, 150, $two);
   imagefilledellipse($img, 240, 150, 150, 150, $three);
   imagefilledellipse($img, 280, 150, 150, 150, $four);
   header('Content-Type: image/png');
   imagepng($img);
   imagedestroy($img);
?>

Output

The following is the output: