(PHP 4, PHP 5, PHP 7, PHP 8)
imagecolortransparent — Define a color as transparent
Gets or sets the transparent color in the given image.
imageA GdImage object, returned by one of the image creation functions, such as imagecreatetruecolor().
colorA color identifier created with imagecolorallocate().
The identifier of the new (or current, if none is specified)
transparent color is returned. If color
is null, and the image has no transparent color, the
returned identifier will be -1.
| Version | Description |
|---|---|
| 8.0.0 |
image expects a GdImage
instance now; previously, a valid gd resource was expected.
|
| 8.0.0 |
color is now nullable.
|
Example #1 imagecolortransparent() example
<?php
// Create a 55x30 image
$im = imagecreatetruecolor(55, 30);
$red = imagecolorallocate($im, 255, 0, 0);
$black = imagecolorallocate($im, 0, 0, 0);
// Make the background transparent
imagecolortransparent($im, $black);
// Draw a red rectangle
imagefilledrectangle($im, 4, 4, 50, 25, $red);
// Save the image
imagepng($im, './imagecolortransparent.png');
?>The above example will output something similar to:
Note:
Transparency is copied only with imagecopymerge() and true color images, not with imagecopy() or pallete images.
Note:
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.