draw_text (Imlib2::Image)

    /*
     * Draw a string with the given Imlib2::Font at the specified coordinates
     *
     * Examples:
     *   font = Imlib2::Font.new 'helvetica/12'
     *   string = 'the blue crow flies at midnight'
     *   image.draw_text font, string, 10, 10
     *
     *   # draw text in a specified color
     *   font = Imlib2::Font.new 'helvetica/12'
     *   string = 'the blue crow flies at midnight'
     *   color = Imlib2::Color::AQUA
     *   image.draw_text font, string, 10, 10, color
     *
     *   # draw text in a specified direction
     *   font = Imlib2::Font.new 'verdana/24'
     *   string = 'the blue crow flies at midnight'
     *   color = Imlib2::Color::YELLOW
     *   direction = Imlib2::Direction::DOWN
     *   image.draw_text font, string, 10, 10, color, direction
     *
     *   # draw text with return metrics
     *   font = Imlib2::Font.new 'arial/36'
     *   string = 'the blue crow flies at midnight'
     *   color = Imlib2::Color::PURPLE
     *   direction = Imlib2::Direction::LEFT
     *   metrics = image.draw_text font, string, 10, 10, color, direction
     *   ['width', 'height', 'horiz_advance', 'vert_advance'].each_index { |i, v|
     *     puts v << ' = ' << metrics[i]
     *   }
     *
     */
    static VALUE image_draw_text(int argc, VALUE *argv, VALUE self) {