是否有任何工作示例如何读取动画 gif，使用 GD 库或 ImageMagick 更改其任何帧中任何像素的颜色并将其再次保存为动画 gif？
我已经在谷歌上搜索了 2 天，但在任何地方都没有找到答案。
编辑：我有几乎完美的解决方案。但是一些透明（动画）gif 不能正确保持其透明度（只有部分透明度被破坏）。
资源：
- 错误图像之一：http ://commons.wikimedia.org/wiki/File:Animation30.gif
- GifFrameExtractor 类：https ://github.com/Sybio/GifFrameExtractor
GIFEncoder 类：http ://www.phpclasses.org/package/3163-PHP-Generate-GIF-animations-from-a-set-of-GIF-images.html
require_once('GIFEncoder.class.php'); require_once('GifFrameExtractor-master/src/GifFrameExtractor/GifFrameExtractor.php'); $gifFilePath = "input.gif"; // check this is an animated GIF if (!\GifFrameExtractor\GifFrameExtractor::isAnimatedGif($gifFilePath)) { \die('not an namiated image'); } $gfe = new \GifFrameExtractor\GifFrameExtractor(); $gfe->extract($gifFilePath); // frames as a GD source $frameImages = $gfe->getFrameImages(); $frameDurations = $gfe->getFrameDurations(); // color used as a transparent color, if any $tColor = array('red' => -1,'green'=>-1,'blue'=>-1); foreach($frameImages as $i => $gdSource) { // do something with gdSource colorize($gdSource); if($i == 0) { //get the color used as transparent // should be for any frame the same $tColor = getTransparentColor($gdSource); } //GIFEncoder works only with binary data or files //It cant work with gd source //Therfore i output the gd source to stdout, catch it //and use it as binary data. //It could be memory consuming, so you might write the //frames as a file and then use them instead of binary data. \ob_start(); // catch output \imagegif($gdSource); // write binary data to output $frameImages[$i] = \ob_get_contents(); //replace GD source by the binary data \ob_end_clean(); } // create animated gif $gif = new \GIFEncoder( $frameImages, //binary data (or path to images on file system) $frameDurations, 0, // infinite loop 2, // dont know what is this for (number 0-3 or -1 to ignore) $tColor['red'], $tColor['green'], $tColor['blue'], 'bin' // or 'url' if $frameImages is array of paths to images on file system ); // write image to file system \FWrite ( \FOpen ( "output.gif", "wb" ), $gif->GetAnimation ( ) ); // send image to browser //Header ( 'Content-type:image/gif' ); //echo $gif->GetAnimation ( );
//有用的函数
/**
* Make grayscale color
* @param $color array('red'=>,'green'=>,'blue'=>);
* @return array('red'=>,'green'=>,'blue'=>);
*/
function transformColor($color) {
$gst = $color['red']*0.15+$color['green']*0.5+$color['blue']*0.35;
$color['red'] = $color['green'] = $color['blue'] = $gst;
return $color;
}
//有用的函数
/**
* Get the transparent color from GD resource.
* If no tranpsarent color, all returned RGB values are -1
* @param $rs GD resource
* @return array('red'=>,'green'=>,'blue'=>)
*/
function getTransparentColor($rs) {
$transparentIndex = \ImageColorTransparent($rs);
$transparentColor = NULL;
if ($transparentIndex >= 0 && $transparentIndex < \ImageColorsTotal($rs)) {
$transparentColor = @\ImageColorsForIndex($rs, $transparentIndex);
}
return $transparentColor ? $transparentColor : array('red' => -1,'green'=>-1,'blue'=>-1);
}
// 用透明度转换 GD 资源 // 可能有问题，因为如果我单独保存帧，它们会出现上述透明度问题
function colorize($rs) {
assert('gd' === \get_resource_type($rs));
// you might want to create copy of the source here
// (instead of resource alias)
$bild = $rs;
//width
$x = \imagesx($bild);
// height
$y = \imagesy($bild);
$transparentIndex = \ImageColorTransparent($rs);
$transparentColor = NULL;
if ($transparentIndex >= 0 && $transparentIndex < \ImageColorsTotal($bild)) {
$transparentColor = @\ImageColorsForIndex($rs, $transparentIndex);
}
\ImageSaveAlpha($bild, TRUE);
\ImageAlphaBlending($bild, FALSE);
$transparentNewIndex = NULL;
$transparentNewColor = NULL;
if (!empty($transparentColor)) {
$transparentIndexNew = \ImageColorAllocate($bild, 255, 0, 255);
\ImageColorTransparent($bild, $transparentIndexNew);
$transparentColorNew = @ImageColorsForIndex($bild, transparentIndexNew);
}
// transform pixels
for ($i = 0; $i < $y; $i++) {
for ($j = 0; $j < $x; $j++) {
$index = \imagecolorat($rs, $j, $i);
$color = \imagecolorsforindex($rs, $index);
if ($index === $transparentIndex) {
$col = $transparentIndexNew;
} else {
$rgb = transformColor($color);
//TODO: we have a problem here, if $rgb ~= $transparentColorNew,
// then this pixel will be transparent and not the desired color
$col = \imagecolorresolvealpha($bild, $rgb['red'], $rgb['green'], $rgb['blue'], intval($color['alpha']));
if($col == $transparentIndexNew) {
//TODO: fix the color not to be transparent
// it do not die with the example gif
//die('This might be a problem, but not the problem describlet above this example');
}
}
\imagesetpixel($bild, $j, $i, $col);
}
}
return $bild;
}