Imagick::blackThresholdImage()

(PECL imagick 2.0.0)

Forces all pixels below the threshold into black

说明

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
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();
}
?>

You need to pass this function a colour:
<?php
$img->blackThresholdImage( "#FFFFFF" );
?>
E.g. this blackens any pixel which isn't pure white.

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();
?>