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PHP GD Color Transparency Using Alpha Blending

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This example shows how to do Color Transparency Using Alpha Blending in php gd.

<?php

define("WIDTH", 300);

define("HEIGHT", 300);

$img = imagecreatetruecolor(WIDTH, HEIGHT);

$black = imagecolorallocate($img, 0, 0, 0);

$yellow = imagecolorallocate($img, 0xFF, 0xFF, 00);

$red = imagecolorallocate($img, 255, 0, 0);

$blue_t = imagecolorallocatealpha($img, 0, 0, 0xFF, 0x40);

imagefill($img, 1, 1, $black);

imageline($img, 0,0, WIDTH-1, HEIGHT-1, $blue_t);

imagefilledrectangle($img, (WIDTH/2)-50, (HEIGHT/2)-50, (WIDTH/2)+50, (HEIGHT/2)+50, $yellow);

imagefilledrectangle($img, (WIDTH/2)-30, (HEIGHT/2)-30, (WIDTH/2)+30, (HEIGHT/2)+30, $red);

imagefilledrectangle($img, 10, 10, WIDTH-11, HEIGHT-11, $blue_t);

header("Content-Type: image/png");

imagepng($img);

?>

After running the program you will get the following output

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Posted on: November 13, 2009 If you enjoyed this post then why not add us on Google+? Add us to your Circles

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