imagealphablending

(PHP 4 >= 4.0.6, PHP 5)

imagealphablending — Set the blending mode for an image

Description

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.

Parameters

image: An image resource, returned by one of the image creation functions, such as imagecreatetruecolor().
blendmode: Whether to enable the blending mode or not. On true color images the default value is TRUE otherwise the default value is FALSE

Return Values

Returns TRUE on success or FALSE on failure.

Examples

Example #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);
?>

Notes

Note: This function requires GD 2.0.1 or later (2.0.28 or later is recommended).