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Imagick::blackThresholdImage

(PECL imagick 2.0.0)

Imagick::blackThresholdImageForces all pixels below the threshold into black

Description

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

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User Contributed Notes 2 notes

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0
Iddles
3 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.
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0
elmer at web-axis dot net
5 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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