Imagick::linearStretchImage()

(PECL imagick 2.0.0)

Stretches with saturation the image intensity

说明

Imagick::linearStretchImage(float $blackPoint,float $whitePoint): bool

Stretches with saturation the image intensity.

参数

$blackPoint: The image black point
$whitePoint: The image white point

返回值

成功时返回TRUE。

范例

Example #1 Imagick::linearStretchImage()

<?php
function linearStretchImage($imagePath, $blackThreshold, $whiteThreshold) {
    $imagick = new \Imagick(realpath($imagePath));
    $pixels = $imagick->getImageWidth() * $imagick->getImageHeight();
    $imagick->linearStretchImage($blackThreshold * $pixels, $whiteThreshold * $pixels);
    header("Content-Type: image/jpg");
    echo $imagick->getImageBlob();
}
?>

"Black" and "white" points here are pixel counts from the darkest and brightest ends respectively. To turn the darkest 90% of the pixels black, and the brightest 5% white, use the following:
<?php
$im = new Imagick ("some image.png");
list ($width, $height) = array_values ($im->getImageGeometry ());
$px = $width * $height;
$im->modulateImage (100, 0, 100);
$im->linearStretchImage ($px * 0.9, $px * 0.05);
$im->writeImage ("temp.jpg");
?>