imagealphablending

(PHP 4 >= 4.0.6, PHP 5)

imagealphablending — Set the blending mode for an image

Beschreibung

bool imagealphablending ( resource $image , bool $blendmode )

imagealphablending() allows for two different modes of drawing on truecolor images. In blending mode, the alpha channel component of the color supplied to all drawing function, such as imagesetpixel() determines how much of the underlying color should be allowed to shine through. As a result, gd automatically blends the existing color at that point with the drawing color, and stores the result in the image. The resulting pixel is opaque. In non-blending mode, the drawing color is copied literally with its alpha channel information, replacing the destination pixel. Blending mode is not available when drawing on palette images.

Parameter-Liste

image: Eine von den verschiedenen Erzeugungsfunktionen wie imagecreatetruecolor() gelieferte Grafikressource.
blendmode: Whether to enable the blending mode or not. Default to FALSE.

Rückgabewerte

Gibt bei Erfolg TRUE zurück, im Fehlerfall FALSE.

Beispiele

Beispiel #1 imagealphablending() usage example


<?php
// Create image
$im = imagecreatetruecolor(100, 100);

// Set alphablending to on
imagealphablending($im, true);

// Draw a square
imagefilledrectangle($im, 30, 30, 70, 70, imagecolorallocate($im, 255, 0, 0));

// Output
header('Content-type: image/png');

imagepng($im);
imagedestroy($im);
?>

Anmerkungen

Hinweis: Diese Funktion setzt die GD-Bibliothek in der Version 2.0.1 oder höher (empfohlen wird mindestens 2.0.28) voraus.