PHP imagecolormatch Function: Matching Palette Colors to True‑Color Images

The imagecolormatch function in PHP modifies a palette‑based image so that its colors more closely match those of a true‑color image. It requires two image resources: $image1 (a true‑color image) and $image2 (a palette image of the same size). The function returns TRUE on success or FALSE on failure.

Parameters image1: a true‑color image resource. image2: a palette image resource with identical dimensions to image1.

Return value

Returns TRUE if the color matching succeeds, otherwise FALSE.

Example usage

<?php
// Setup the true‑color and palette images
$im1 = imagecreatefrompng('./gdlogo.png');
$im2 = imagecreate(imagesx($im1), imagesy($im1));

// Add some colors to $im2
$colors[] = imagecolorallocate($im2, 255, 36, 74);
$colors[] = imagecolorallocate($im2, 40, 0, 240);
$colors[] = imagecolorallocate($im2, 82, 100, 255);
$colors[] = imagecolorallocate($im2, 84, 63, 44);

// Match these colors with the true‑color image
imagecolormatch($im1, $im2);

// Free memory
imagedestroy($im1);
imagedestroy($im2);
?>