imagelayereffect
(PHP 4 >= 4.3.0, PHP 5, PHP 7)
imagelayereffect — Set the alpha blending flag to use layering effects
Description
bool imagelayereffect
( resource
$image
, int $effect
)Set the alpha blending flag to use layering effects.
Parameters
-
image -
An image resource, returned by one of the image creation functions, such as imagecreatetruecolor().
-
effect -
One of the following constants:
-
IMG_EFFECT_REPLACE -
Use pixel replacement (equivalent of passing
TRUEto imagealphablending()) -
IMG_EFFECT_ALPHABLEND -
Use normal pixel blending (equivalent of passing
FALSEto imagealphablending()) -
IMG_EFFECT_NORMAL -
Same as
IMG_EFFECT_ALPHABLEND. -
IMG_EFFECT_OVERLAY - Overlay has the effect that black background pixels will remain black, white background pixels will remain white, but grey background pixels will take the colour of the foreground pixel.
-
IMG_EFFECT_MULTIPLY - Overlays with a multiply effect.
-
Return Values
Returns TRUE on success or FALSE on failure.
Changelog
| Version | Description |
|---|---|
| 7.2.0 |
Added IMG_EFFECT_MULTIPLY (requires system libgd >=
2.1.1 or the bundled libgd).
|
Examples
Example #1 imagelayereffect() example
<?php
// Setup an image
$im = imagecreatetruecolor(100, 100);
// Set a background
imagefilledrectangle($im, 0, 0, 100, 100, imagecolorallocate($im, 220, 220, 220));
// Apply the overlay alpha blending flag
imagelayereffect($im, IMG_EFFECT_OVERLAY);
// Draw two grey ellipses
imagefilledellipse($im, 50, 50, 40, 40, imagecolorallocate($im, 100, 255, 100));
imagefilledellipse($im, 50, 50, 50, 80, imagecolorallocate($im, 100, 100, 255));
imagefilledellipse($im, 50, 50, 80, 50, imagecolorallocate($im, 255, 100, 100));
// Output
header('Content-type: image/png');
imagepng($im);
imagedestroy($im);
?>
The above example will output something similar to:
Notes
Before PHP 5.5.0, this function is only available if PHP is compiled with the bundled version of the GD library.