(PHP 4, PHP 5)
imagecolortransparent — Define a color as transparent
Sets the transparent color in the given
The identifier of the new (or current, if none is specified) transparent color is returned. If
color is not specified, and the image has no transparent color, the returned identifier will be -1.
Example #1 imagecolortransparent() example
// Create a 55x30 image
$im = imagecreatetruecolor(55, 30);
$red = imagecolorallocate($im, 255, 0, 0);
$black = imagecolorallocate($im, 0, 0, 0);
// Make the background transparent
// Draw a red rectangle
imagefilledrectangle($im, 4, 4, 50, 25, $red);
// Save the image
The above example will output something similar to:
The transparent color is a property of the image, transparency is not a property of the color. Once you have set a color to be the transparent color, any regions of the image in that color that were drawn previously will be transparent.