Imagick::thresholdImage

(PECL imagick 2, PECL imagick 3)

Imagick::thresholdImageChanges the value of individual pixels based on a threshold

Description

public Imagick::thresholdImage(float $threshold, int $channel = Imagick::CHANNEL_DEFAULT): bool

Changes the value of individual pixels based on the intensity of each pixel compared to threshold. The result is a high-contrast, two color image.

Parameters

threshold

channel

Return Values

Returns true on success.

Examples

Example #1 Imagick::thresholdImage()

<?php
function thresholdimage($imagePath, $threshold, $channel) {
$imagick = new \Imagick(realpath($imagePath));
$imagick->thresholdimage($threshold * \Imagick::getQuantum(), $channel);
header("Content-Type: image/jpg");
echo
$imagick->getImageBlob();
}

?>

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User Contributed Notes 1 note

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1
php t traction dot de
12 years ago
getQuantumRange() can be handy here:

<?php
$i
= new Imagick($imageFile);
$max = $i->getQuantumRange();
$max = $max["quantumRangeLong"];
$i->thresholdImage(0.77 * $max);
?>
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