php教程

Imagick::thresholdImage

(PECL imagick 2.0.0)

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

说明

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.

参数

threshold

channel

返回值

成功时返回 TRUE

范例

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();
}

?>

User Contributed Notes

php t traction dot de 29-Jun-2012 07:25
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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