Dutch PHP Conference 2023 - Call for Papers


(PECL imagick 2, PECL imagick 3)

Imagick::levelImageAdjusts the levels of an image


public Imagick::levelImage(
    float $blackPoint,
    float $gamma,
    float $whitePoint,
    int $channel = Imagick::CHANNEL_DEFAULT
): bool

Adjusts the levels of an image by scaling the colors falling between specified white and black points to the full available quantum range. The parameters provided represent the black, mid, and white points. The black point specifies the darkest color in the image. Colors darker than the black point are set to zero. Mid point specifies a gamma correction to apply to the image. White point specifies the lightest color in the image. Colors brighter than the white point are set to the maximum quantum value.



The image black point


The gamma value


The image white point


Provide any channel constant that is valid for your channel mode. To apply to more than one channel, combine channeltype constants using bitwise operators. Refer to this list of channel constants.

Valor Retornado

Retorna true em caso de sucesso.


Lança uma exceção ImagickException em caso de erro.


Exemplo #1 Imagick::levelImage()

function levelImage($blackPoint, $gamma, $whitePoint) {
$imagick = new \Imagick();
$imagick->newPseudoimage(500, 500, 'gradient:black-white');

$quantum = $imagick->getQuantum();
$imagick->levelImage($blackPoint / 100 , $gamma, $quantum * $whitePoint / 100);

header("Content-Type: image/png");


add a note

User Contributed Notes 1 note

Maxim Lovchikov
12 years ago
I have a trouble with this method because think that quantum range is 0 - 255.
But quantum range for levelImage is 0-65535. You can get quantum range with Imagick::getQuantumRange
There is a right piece of code

$img->levelImage (0, 1.0, 65535);
To Top