PHP Manual: Changes the color value of any pixel that matches target

Description

public bool Imagick::opaquePaintImage(
    mixed $target,
    mixed $fill,
    float $fuzz,
    bool $invert,
    int $channel = Imagick::CHANNEL_DEFAULT
)

Changes any pixel that matches color with the color defined by fill. This method is available if Imagick has been compiled against ImageMagick version 6.3.8 or newer.

Parameters

target: ImagickPixel object or a string containing the color to change
fill: The replacement color
fuzz: The amount of fuzz. For example, set fuzz to 10 and the color red at intensities of 100 and 102 respectively are now interpreted as the same color.
invert: If true paints any pixel that does not match the target color.
channel: Provide any channel constant that is valid for your channel mode. To apply to more than one channel, combine channel constants using bitwise operators. Defaults to Imagick::CHANNEL_DEFAULT. Refer to this list of channel constants

Return Values

Returns true on success.