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Imagick::blackThresholdImage

(PECL imagick 2.0.0)

Imagick::blackThresholdImageForces all pixels below the threshold into black

说明

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.

参数

threshold

The threshold below which everything turns black

返回值

成功时返回 TRUE

更新日志

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

范例

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

up
1
Iddles
6 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
8 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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