Imagick::blackThresholdImage

(PECL imagick 2, PECL imagick 3)

Imagick::blackThresholdImage — Forces all pixels below the threshold into black

说明

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.

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
PECL imagick 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();
}

?>

User Contributed Notes

Iddles 06-Jul-2011 05:35


You need to pass this function a colour:



<?php



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



?>



E.g. this blackens any pixel which isn't pure white.

elmer at web-axis dot net 30-Nov-2008 03:33


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();


?>