(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
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.
Una risorsa immagine, restituita da una delle funzioni di creazione immagine, come imagecreatetruecolor().
Restituisce TRUE in caso di successo, FALSE in caso di fallimento.
Nota: Questa funzione necessita di GD 2.0.1 o successivi.