Example

function setImageArtifact()
{
    $src1 = new \Imagick(realpath("./images/artifact/source1.png"));
    $src2 = new \Imagick(realpath("./images/artifact/source2.png"));

    $src2->setImageVirtualPixelMethod(\Imagick::VIRTUALPIXELMETHOD_TRANSPARENT);
    $src2->setImageArtifact('compose:args', "1,0,-0.5,0.5");
    $src1->compositeImage($src2, Imagick::COMPOSITE_MATHEMATICS, 0, 0);
    
    $src1->setImageFormat('png');
    header("Content-Type: image/png");
    echo $src1->getImagesBlob();
}