Imagick
PHP Manual

Imagick::blackThresholdImage

Forces all pixels below the threshold into black

Description

public bool Imagick::blackThresholdImage(mixed $threshold)

Is like Imagick::thresholdImage() but forces all pixels below the threshold into black while leaving all pixels above the threshold unchanged.

Parameters

threshold

The threshold below which everything turns black

Return Values

Returns true on success.

Changelog

Version Description
PECL imagick 2.1.0 Now allows a string representing the color as a parameter. Previous versions allow only an ImagickPixel object.

Examples

Example #1 Imagick::blackThresholdImage

<?php
function blackThresholdImage($imagePath, $thresholdColor) {
    $imagick = new \Imagick(realpath($imagePath));
    $imagick->blackthresholdimage($thresholdColor);
    header("Content-Type: image/jpg");
    echo $imagick->getImageBlob();
}

?>