(PHP 4 >= 4.3.2, PHP 5)
imagesavealpha — Set the flag to save full alpha channel information (as opposed to single-color transparency) when saving PNG images
$image
, bool $saveflag
)imagesavealpha() sets the flag to attempt to save full alpha channel information (as opposed to single-color transparency) when saving PNG images.
You have to unset alphablending (imagealphablending($im, false)), to use it.
Alpha channel is not supported by all browsers, if you have problem with your browser, try to load your script with an alpha channel compliant browser, e.g. latest Mozilla.
image
Eine von den verschiedenen Erzeugungsfunktionen wie imagecreatetruecolor() gelieferte Grafikressource.
saveflag
Whether to save the alpha channel or not. Default to FALSE.
Gibt bei Erfolg TRUE zurück. Im Fehlerfall wird FALSE zurückgegeben.
Beispiel #1 imagesavealpha() example
<?php
// Load a png image with alpha channels
$png = imagecreatefrompng('./alphachannel_example.png');
// Do required operations
// Turn off alpha blending and set alpha flag
imagealphablending($png, false);
imagesavealpha($png, true);
// Output image to browser
header('Content-Type: image/png');
imagepng($png);
imagedestroy($png);
?>
Hinweis: Diese Funktion setzt die GD-Bibliothek in der Version 2.0.1 oder höher (empfohlen wird mindestens 2.0.28) voraus.