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imagecolorresolvealpha> <imagecolormatch
Last updated: Fri, 18 Jul 2008

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imagecolorresolve

(PHP 4, PHP 5)

imagecolorresolve — Get the index of the specified color or its closest possible alternative

Description

int imagecolorresolve ( resource $image , int $red , int $green , int $blue )

This function is guaranteed to return a color index for a requested color, either the exact color or the closest possible alternative.

If you created the image from a file, only colors used in the image are resolved. Colors present only in the pallete are not resolved.

Parameters

image

An image resource, returned by one of the image creation functions, such as imagecreatetruecolor().

red

Value of red component

green

Value of green component

blue

Value of blue component

Return Values

Returns a color index.



add a note add a note User Contributed Notes
imagecolorresolve
ceo at l-i-e dot com
03-Jan-2002 11:55
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);
}

imagecolorresolvealpha> <imagecolormatch
Last updated: Fri, 18 Jul 2008
 
 
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