PHP Manual: Paints pixels transparent

Description

public bool Imagick::transparentPaintImage(
    mixed $target,
    float $alpha,
    float $fuzz,
    bool $invert
)

Paints pixels matching the target color transparent. This method is available if Imagick has been compiled against ImageMagick version 6.3.8 or newer.

Parameters

target: The target color to paint
alpha: The level of transparency: 1.0 is fully opaque and 0.0 is fully transparent.
fuzz: The amount of fuzz. For example, set fuzz to 10 and the color red at intensities of 100 and 102 respectively are now interpreted as the same color.
invert: If true paints any pixel that does not match the target color.

Return Values

Returns true on success.

Examples

Example #1 Imagick::transparentPaintImage

<?php
function transparentPaintImage($color, $alpha, $fuzz) {
    $imagick = new \Imagick(realpath("images/BlueScreen.jpg"));

    //Need to be in a format that supports transparency
    $imagick->setimageformat('png');

    $imagick->transparentPaintImage(
        $color, $alpha, $fuzz * \Imagick::getQuantum(), false
    );

    //Not required, but helps tidy up left over pixels
    $imagick->despeckleimage();

    header("Content-Type: image/png");
    echo $imagick->getImageBlob();
}

?>