(PECL imagick 2.0.0)
Imagick::blackThresholdImage — Forces all pixels below the threshold into black
Is like Imagick::thresholdImage() but forces all pixels below the threshold into black while leaving all pixels above the threshold unchanged.
threshold
The threshold below which everything turns black
成功时返回 TRUE。
| 版本 | 说明 |
|---|---|
| 2.1.0 | Now allows a string representing the color as a parameter. Previous versions allow only an ImagickPixel object. |
Iddles (2011-07-06 17:35:24)
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 (2008-11-30 15:33:54)
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();
?>