Imbo\Image\Transformation\Border::expandImage PHP Method

    private function expandImage($color, $borderWidth, $borderHeight, Image $image)
    {
        $imageWidth = $image->getWidth();
        $imageHeight = $image->getHeight();
        $original = clone $this->imagick;
        // Clear the original and make the canvas
        $this->imagick->clear();
        $this->imagick->newImage($imageWidth + $borderWidth * 2, $imageHeight + $borderHeight * 2, $color);
        $this->imagick->setImageAlphaChannel(Imagick::ALPHACHANNEL_OPAQUE);
        $this->imagick->setImageFormat($image->getExtension());
        $this->imagick->compositeImage($original, Imagick::COMPOSITE_COPY, $borderWidth, $borderHeight);
    }