Imagick::blackThresholdImage

(PECL imagick 2, PECL imagick 3)

Imagick::blackThresholdImageForces all pixels below the threshold into black

Descrizione

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.

Elenco dei parametri

threshold

The threshold below which everything turns black

Valori restituiti

Restituisce true in caso di successo.

Log delle modifiche

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

Esempi

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();
}

?>

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User Contributed Notes 2 notes

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2
Iddles
12 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
15 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();
?>
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