Imagick
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Imagick::whiteThresholdImage

(PECL imagick 2.0.0)

Imagick::whiteThresholdImage — Force all pixels above the threshold into white

说明

bool Imagick::whiteThresholdImage ( mixed $threshold )

Is like Imagick::ThresholdImage() but force all pixels above the threshold into white while leaving all pixels below the threshold unchanged.

参数

threshold

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.

Imagick
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PHP手册 - N: Force all pixels above the threshold into white

用户评论:

elmer at web-axis dot net (30-Nov-2008 11:32)

Here's a example of this function:

<?php
  $img = new Imagick();
  $img->readImage($image_file_name);
  $img->whiteThresholdImage('grey');
  $img->writeImage($thumb_file_name);
  $img->clear();
  $img->destroy();
?>