如何使用PHP GD库将PNG转换为8位PNG

问题描述：

我想编写一个例程，该例程将PNG图像路径作为参数并将该图像转换为8位PNG图像.我需要为此使用PHP GD库.

I want to write a routine which takes PNG image path as parameter and convert that image into 8-bit PNG image. I need to use PHP GD library for this.

答

要使用此功能将任何PNG图像转换为8位PNG，我刚刚创建了

To convert any PNG image to 8-bit PNG use this function, I've just created

 function convertPNGto8bitPNG ($sourcePath, $destPath) {

     $srcimage = imagecreatefrompng($sourcePath);
     list($width, $height) = getimagesize($sourcePath);

     $img = imagecreatetruecolor($width, $height);
     $bga = imagecolorallocatealpha($img, 0, 0, 0, 127);
     imagecolortransparent($img, $bga);
     imagefill($img, 0, 0, $bga);
     imagecopy($img, $srcimage, 0, 0, 0, 0, $width, $height);
     imagetruecolortopalette($img, false, 255);
     imagesavealpha($img, true);

     imagepng($img, $destPath);
     imagedestroy($img);

 }

参数

$ sourcePath -源PNG文件的路径
$ destPath -目标PNG文件的路径

Parameters

$sourcePath - Path to source PNG file
$destPath - Path to destination PNG file

我建议在运行此代码之前确保$sourcePath存在并且$destPath可写.也许此功能不适用于某些透明图像.

I recommend to make sure that $sourcePath exists and $destPath is writable before running this code. Maybe this function won't work with some transparent images.

convertPNGto8bitPNG ('pfc.png', 'pfc8bit.png');

示例(原始-> 8位)

(来源:pfc.png)原始PNG图像

(目标:pfc8bit.png)已转换的PNG图像(8位)

(Destination: pfc8bit.png) CONVERTED PNG IMAGE (8-bit)

希望有人发现这有帮助.

Hope someone finds this helpful.

如何使用PHP GD库将PNG转换为8位PNG

参数

Parameters

示例(原始-> 8位)

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