(PHP 4, PHP 5)
imagecolorresolve — 取得指定颜色的索引值或有可能得到的最接近的替代值
$image
, int $red
, int $green
, int $blue
)本函数可以保证对所请求的颜色返回一个颜色索引，要么是确切值要么是所能得到最接近的替代值。
如果从文件创建了图像，只有图像中使用了的颜色会被辨析。仅出现在调色板中的颜色不会被辨析。
tom (2012-04-20 22:08:39)
It seems that imagecolorresolve is adding the colors to the palette when it can't find them!
ceo at l-i-e dot com (2002-01-03 03:55:32)
Okay, so sometimes it's really IMPORTANT to get the exact color you want, only it's not *IN* the Image, and ImageColorResolve just isn't "close enough".
The following code is a disgustingly gross hack, rather slow, but it does that.
$colorcount = array();
for ($x = 0; $x < $width; $x++){
for ($y = 0; $y < $height; $y++){
$colorindex = imagecolorat($jpg, $x, $y);
if (!isset($colorcount[$colorindex])){
$colorcount[$colorindex] = 1;
}
else{
$colorcount[$colorindex]++;
}
}
}
asort($colorcount);
reset($colorcount);
$black = imagecolorexact($jpg, 0, 0, 0);
if ($black == -1){
$goner = key($colorcount);
$rgb = imagecolorsforindex($jpg, $goner);
#error_log("Need black: About to kill $goner ($rgb[red], $rgb[green], $rgb[blue]) which was only used in $colorcount[$goner] pixels", 0);
unset($colorcount[$goner]);
imagecolordeallocate($jpg, $goner);
$black = imagecolorallocate($jpg, 0, 0, 0);
}
if ($black == -1){
$black = imagecolorresolve($jpg, 0, 0, 0);
#error_log("Damn! STILL couldn't allocate the color!", 0);
}