imagelayereffect

    (PHP 4 >= 4.3.0, PHP 5, PHP 7, PHP 8)

    imagelayereffect — Set the alpha blending flag to use layering effects

    Description

    imagelayereffect(GdImage $image, int $effect): bool

    Set the alpha blending flag to use layering effects.

    Parameters

    image

    A GdImage object, returned by one of the image creation functions, such as imagecreatetruecolor().

    effect

    One of the following constants:

    IMG_EFFECT_REPLACE
    Use pixel replacement (equivalent of passing true to imagealphablending())
    IMG_EFFECT_ALPHABLEND
    Use normal pixel blending (equivalent of passing false to imagealphablending())
    IMG_EFFECT_NORMAL
    Same as IMG_EFFECT_ALPHABLEND.
    IMG_EFFECT_OVERLAY
    Overlay has the effect that black background pixels will remain black, white background pixels will remain white, but grey background pixels will take the colour of the foreground pixel.
    IMG_EFFECT_MULTIPLY
    Overlays with a multiply effect.

    Return Values

    Returns true on success or false on failure.

    Changelog

    Version Description
    8.0.0 image expects a GdImage instance now; previously, a valid gd resource was expected.
    7.2.0 Added IMG_EFFECT_MULTIPLY (requires system libgd >= 2.1.1 or the bundled libgd).

    Examples

    Example #1 imagelayereffect() example

    <?php
    // Setup an image
    $im = imagecreatetruecolor(100, 100);

    // Set a background
    imagefilledrectangle($im, 0, 0, 100, 100, imagecolorallocate($im, 220, 220, 220));

    // Apply the overlay alpha blending flag
    imagelayereffect($im, IMG_EFFECT_OVERLAY);

    // Draw two grey ellipses
    imagefilledellipse($im, 50, 50, 40, 40, imagecolorallocate($im, 100, 255, 100));
    imagefilledellipse($im, 50, 50, 50, 80, imagecolorallocate($im, 100, 100, 255));
    imagefilledellipse($im, 50, 50, 80, 50, imagecolorallocate($im, 255, 100, 100));

    // Output
    header('Content-type: image/png');

    imagepng($im);
    imagedestroy($im);
    ?>

    The above example will output something similar to:

    Output of example : imagelayereffect()

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