PHP: imagecolorresolve

imagecolorresolve

(PHP 3 >= 3.0.2, 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.

See also imagecolorclosest().

imagecolorresolve

ceo at l-i-e dot com
03-Jan-2002 03:55


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);

}