Imagick::linearStretchImage

    (PECL imagick 2, PECL imagick 3)

    Imagick::linearStretchImage — Stretches with saturation the image intensity

    Beschreibung

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

    Stretches with saturation the image intensity.

    Parameter-Liste

    blackPoint

    The image black point

    whitePoint

    The image white point

    Rückgabewerte

    Liefert true bei Erfolg.

    Beispiele

    Beispiel #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();
    }

    ?>

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    User Contributed Notes 1 note

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    SkepticaLee
    10 years ago
    "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");
    ?>
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