可能导致“颜色索引超出范围"的原因是什么? imagecolorsforindex()错误? [英] What could cause a "color index out of range" error for imagecolorsforindex()?
问题描述
在将修补程序调整为一大堆JPG,PNG和GIF文件的大小时,PHP意外地死机,并显示以下错误消息:
When doing a patch resize to a big bunch of JPG, PNG and GIF files, PHP drops dead quite unexpectedly with the following error message:
imagecolorsforindex()[function.imagecolorsforindex]: 颜色索引226超出范围
imagecolorsforindex() [function.imagecolorsforindex]: Color index 226 out of range
相关的代码片段是:
protected function preserveTransparency($img, $resized, $ftype) {
if (($ftype == IMAGETYPE_PNG) || ($ftype == IMAGETYPE_GIF)) {
$tidx = imagecolortransparent($img);
if ($tidx >= 0) {
$transColor = imagecolorsforindex($img, $tidx);
$tidx = imagecolorallocate($resized, $transColor['red'], $transColor['green'], $transColor['blue']);
imagefill($resized, 0, 0, $tidx);
imagecolortransparent($resized, $tidx);
} elseif ($ftype == IMAGETYPE_PNG) {
imagealphablending($resized, false);
imagesavealpha($resized, true);
$transparent = imagecolorallocatealpha($resized, 255, 255, 255, 127);
imagefill($resized, 0, 0, $transparent);
}
}
}
如果imagecolortransparent
已返回颜色索引,怎么可能不存在?
How could a color index not exist if was already returned by imagecolortransparent
?
推荐答案
听起来imagecolortransparent($img)
返回的索引大于所讨论图像的托盘尺寸.
It sounds like the index returned by imagecolortransparent($img)
is larger than the pallet size of the image in question.
透明色的索引是图像的属性,而不是托盘的属性,因此有可能使用该索引设置超出托盘大小来创建图像,但是我希望PHP能够在这种情况下已检测到此问题并从imagecolortransparent()
返回-1.
The index of the transparency color is a property of the image, rather than a property of the pallet, so it's possible that an image could be created with this index set outside the pallet size, but I would have hoped that PHP would have detected this and returned -1 from imagecolortransparent()
in this situation.
您可以通过将调用添加到 imagecolorstotal 到您的代码:
You could check if this is what is happening by adding a call to imagecolorstotal to your code:
$tidx = imagecolortransparent($img);
$palletsize = imagecolorstotal($img);
if ($tidx >= 0 && $tidx < $palletsize) {
$transColor = imagecolorsforindex($img, $tidx);
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