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.

示例

示例 #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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用户贡献的备注 2 notes

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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.

down

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();

?>

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备份地址：http://www.lvesu.com/blog/php/imagick.blackthresholdimage.php