imagelayereffect

(PHP 4 >= 4.3.0, PHP 5, PHP 7, PHP 8)

imagelayereffect — Set the alpha blending flag to use layering effects

Descrizione

imagelayereffect(GdImage $image, int $effect): bool

Set the alpha blending flag to use layering effects.

Elenco dei parametri

image

Una risorsa immagine, restituita da una delle funzioni di creazione immagine, come imagecreatetruecolor().

effect

One of the following constants:

IMG_EFFECT_REPLACE: Use pixel replacement (equivalent of passing true to imagealphablending())
IMG_EFFECT_ALPHABLEND: Use normal pixel blending (equivalent of passing false to 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.

Valori restituiti

Restituisce true in caso di successo, false in caso di fallimento.

Log delle modifiche

Versione	Descrizione
8.0.0	`image` expects a GdImage instance now; previously, a valid `gd` resource was expected.
7.2.0	Added `IMG_EFFECT_MULTIPLY` (requires system libgd >= 2.1.1 or the bundled libgd).

Esempi

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);
?>

Il precedente esempio visualizzerà qualcosa simile a: