PHP Conference Nagoya 2025

Imagick::blackThresholdImage

(PECL imagick 2, PECL imagick 3)

Imagick::blackThresholdImageForces all pixels below the threshold into black

Опис

public Imagick::blackThresholdImage(mixed $threshold): bool

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

Параметри

threshold

The threshold below which everything turns black

Значення, що повертаються

Повертає true в разі успіху.

Журнал змін

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

Приклади

Приклад #1 Imagick::blackThresholdImage()

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

?>

add a note

User Contributed Notes 2 notes

up
4
Iddles
13 years ago
You need to pass this function a colour:

<?php

$img
->blackThresholdImage( "#FFFFFF" );

?>

E.g. this blackens any pixel which isn't pure white.
up
1
elmer at web-axis dot net
16 years ago
Here's a example of this function:

<?php
$img
= new Imagick();
$img->readImage($image_file_name);
$img->blackThresholdImage('grey');
$img->writeImage($thumb_file_name);
$img->clear();
$img->destroy();
?>
To Top