(PHP 3 >= 3.0.2, PHP 4, PHP 5)
imagecolorresolve -- Get the index of the specified color or its closest possible alternativeThis 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.
imageAn image resource, returned by one of the image creation functions, such as imagecreatetruecolor().
redValue of red component
greenValue of green component
blueValue of blue component