如何在PHP中使用ImageMagick为文本添加内部阴影

Question

我从http://www.imagemagick.org/

找到了这个下面的代码

convert button.png \( +clone -background black -shadow 75x0+0-5 \) \
\( -clone 0 -alpha off -virtual-pixel black -blur 0x2 -alpha on \) \
-delete 0 -background none -layers merge +repage button3.png

上述代码的输出是：

我用PHP试过这个

    $textLayer = new Imagick();
    $textLayer->newImage(500, 400, new ImagickPixel('transparent'));

    $draw = new ImagickDraw();
    $draw->setFillColor(#000);
    $draw->setFillOpacity(0.7);
    $draw->setTextKerning(0);
    $draw->setFont('impact.ttf');
    $draw->setFontSize(110);
    $draw->skewY(-90);
    $draw->setGravity(Imagick::GRAVITY_CENTER);

    $textLayer->annotateImage($draw, -10, 0, 30, 'WELCOME');
    $textLayer->setImageFormat('png');

    header("Content-Type: image/png");
    echo $textLayer`

我看到透明背景的文字，请帮我修改代码以获得内部阴影。感谢。