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PhpDig is a PHP MySQL based
Web Spider & Search Engine.



imagecolorset — Replaces one color with another color.


bool imagecolorset(image, color, red, green, blue);
int image: Image identifier
int color: Color to change
int red: Red component of new color
int green: Green component of new color
int blue: Blue component of new color


TRUE on success; FALSE on error


Changes one color already in an image to a new specified color. Useful for replacing a block of color in an image without having to do any possibly complex redrawing operations. In the following example, the closest blue is found in the image using imagecolorclosest() and then replaced with green. This demonstrates how a color doesn't even need to be known exactly to be replaced.


Example 400. Replace blue with green

header("Content-type: image/png");
$im = imagecreate(200, 200);
$red = imagecolorallocate($im, 255, 0, 0);
$offblue = imagecolorallocate($im, 90, 90, 200);
imagefill($im, 0, 0, $red);
imagefilledrectangle($im, 10, 10, 40, 40, $offblue);
// above could come from an uploaded image
// find a blue in the image
$newblue = imagecolorclosest($im, 0, 0, 255);
// change it to green
imagecolorset($im, $newblue, 0, 255, 0);

PHP Functions Essential Reference. Copyright © 2002 by New Riders Publishing (Authors: Zak Greant, Graeme Merrall, Torben Wilson, Brett Michlitsch). This material may be distributed only subject to the terms and conditions set forth in the Open Publication License, v1.0 or later (the latest version is presently available at The authors of this book have elected not to choose any options under the OPL. This online book was obtained from and is designed to provide information about the PHP programming language, focusing on PHP version 4.0.4 for the most part. The information is provided on an as-is basis, and no warranty or fitness is implied. All persons and entities shall have neither liability nor responsibility to any person or entity with respect to any loss or damage arising from the information contained in this book.

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