imagecolormatch

(PHP 4 >= 4.3.0, PHP 5, PHP 7, PHP 8)

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

imagecolormatch(resource $image1, resource $image2): bool

使一个图像中调色板版本的颜色与真彩色版本更能匹配。

参数

image1: 真彩色图像连接资源。
image2: 必须是调色板图像，而且和 image1 的大小必须相同。

返回值

成功时返回 true，或者在失败时返回 false。

范例

示例 #1 imagecolormatch() 例子


<?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

参见

imagecreatetruecolor() - 新建一个真彩色图像

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User Contributed Notes 3 notes

down

albriNOght at anSPAMre dot net ¶

16 years ago


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.

down

gk at karko dot net ¶

11 years ago


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

down

Samantha ¶

18 years ago


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.

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官方地址：https://www.php.net/manual/en/function.imagecolormatch.php

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imagecolormatch

说明

参数

返回值

范例

注释

参见

User Contributed Notes 3 notes