imagelayereffect

Set the alpha blending flag to use layering effects

&reftitle.description; `bool` `imagelayereffect` `GdImage` `image` `int` `effect`

Set the alpha blending flag to use layering effects.

&reftitle.parameters;

&gd.image.description;

`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.

&reftitle.returnvalues;

&return.success;

&reftitle.changelog;

&Version; | &Description;
&gd.changelog.image-param;
7.2.0 | Added `IMG_EFFECT_MULTIPLY` (requires system libgd >= 2.1.1 or the bundled libgd).

&reftitle.examples;

### `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);
    ?>

&example.outputs.similar; Output of example : imagelayereffect()