The imagecolortransparent() function is used to set the color of a transparent image.
Syntax
imagecolortransparent ( img, color )
Parameters
img: Create image with imagecreatetruecolor() function.
color: Color identifier created with imagecolorallocate().
Return
The imagecolortransparent() function returns the identifier of the new transparent color. The return value is -1 if color is not specified and the image has no transparent color.
Example
The following is an example
<?php
$img = imagecreatetruecolor(500, 400);
$blue = imagecolorallocate($img, 0, 0, 255);
$transparent = imagecolorallocate($img, 0, 0, 0);
imagecolortransparent($img, $transparent);
imagefilledrectangle($img, 80, 90, 400, 220, $blue);
header('Content-Type: image/png');
imagepng($img);
imagedestroy($img);
?>Output
The following is the output:
