imagecolormatch

(PHP 4 >= 4.3.0, PHP 5)

imagecolormatch — 使一个图像中调色板版本的颜色与真彩色版本更能匹配

说明

bool imagecolormatch ( resource $image1 , resource $image2 )

image1 必须是真彩色图像，image2 必须是调色板图像，而且 image1 和 image2 的大小必须相同。

成功时返回 TRUE，或者在失败时返回 FALSE.

Note: 此函数仅在与 GD 库捆绑编译的 PHP 版本中可用。

Note: 此函数需要 GD 2.0.1 或更高版本(推荐 2.0.28 及更高版本)。

参见 imagecreatetruecolor()。

参数

image1: A truecolor image link resource.
image2: A palette image link resource pointing to an image that has the same size as image1.

返回值

成功时返回 TRUE，或者在失败时返回 FALSE.

范例

Example #1 imagecolormatch() example


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

// Add some colors to $im2
$colors   = Array();
$colors[] = imagecolorallocate($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 from memory
imagedestroy($im1);
imagedestroy($im2);
?>

注释

Note: 此函数仅在与 GD 库捆绑编译的 PHP 版本中可用。

Note: 此函数需要 GD 2.0.1 或更高版本(推荐 2.0.28 及更高版本)。

参见

imagecreatetruecolor() - 新建一个真彩色图像

PHP手册 - N: 使一个图像中调色板版本的颜色与真彩色版本更能匹配

用户评论:

gk at karko dot net (28-Jun-2010 05:42)

Those that have Ubuntu servers note, that this function is added in PHP's GD library fork and is not available by default in Ubuntu php5-gd package. Here's how-to install the PHP GD version: http://preview.tinyurl.com/yel4r7t

albriNOght at anSPAMre dot net (12-Dec-2005 05:22)

This function appears to work by changing the values of the colors of the paletted image -- no good if you're trying to force the resultant image to stick with certain pre-defined color values.

Samantha (09-Feb-2004 03:14)

This function is a godsend! It works exactly as documented. I'm working on an application where I need to take a transparent GIF, matte the GIF on a user defined background color, and finally scale the GIF based on a user defined %. The only way I could get this to work so that the final image was high quality, ie: no jagged edges, and a smooth scale, was to convert the GIF to a JPG, and then copy the JPG into a new GIF image like this: // open transparent gif $GIFimg = imagecreatefromgif($file_path); // create jpg image $JPGimg = imagecreatetruecolor($width, $height); // copy GIF to JPG imagecopy($JPGimg, $GIFimg, 0, 0, 0, 0, $width, $height); // create a true color image $JPGscaled = imagecreatetruecolor($n_width, $n_height); // scale the new JPG using the truecolor image imagecopyresampled($JPGscaled, $JPGimg, 0, 0, 0, 0, $new_width, $new_height, $width, $height); // create final GIF image $GIFfinal = imagecreate($n_width, $n_height); // copy the scaled JPG back to a GIF imagecopymerge($GIFfinal, $JPGscaled, 0, 0, 0, 0, $n_width, $n_height, 100); This worked great except the final step, copying the JPG to a GIF. If the JPG had too many colors, the function would index the colors to make it a palette image. So what would end up happening is the final image contained INCORRECT colors. Adding this one line at the bottom of the code fixed everything. imagecolormatch($JPGscaled, $GIFfinal); I hope this helps anyone who is converting images back and forth and dealing with palette issues and color correction. Also, be aware that the above code is a sample and will not work by copying and pasting.