draw_rectangle (Imlib2::Image)

    /*
     * Draw a rectangle outline at the specified coordinates.
     *
     * Examples:
     *   # draw rectangle around edge of image using context color
     *   rect = [1, 1, im.width - 2, im.height - 2]
     *   im.draw_rect rect
     *
     *   # draw magenta rectangle outline in top-left corner of image
     *   color = Imlib2::Color::MAGENTA
     *   im.draw_rect [0, 0], [im.width / 2, im.height / 2], color
     *
     *   # draw square from 10, 10 to 30, 30 using context color
     *   im.draw_rect [10, 10, 20, 20]
     *
     */
    static VALUE image_draw_rect(int argc, VALUE *argv, VALUE self) {