draw_line (Imlib2::Image)

    /*
     * Draw a line at the specified coordinates.
     *
     * Examples:
     *   # draw line from 10, 10 to 20, 20 using context color
     *   im.draw_line 10, 10, 20, 20
     *
     *   # draw magenta line from 5, 10 to 15, 20
     *   im.draw_line 5, 10, 15, 20, Imlib2::Color::MAGENTA
     *
     *   # draw line from 10, 15 to 20, 25 using context color
     *   im.draw_pixel [10, 15], [20, 25]
     *
     *   # draw line from 1000, 2000 to 2100, 4200 with funky color
     *   my_color = Imlib2::Color::CmykColor.new 100, 255, 0, 128
     *   im.draw_line [1000, 2000], [2100, 4200], my_color
     *
     */
    static VALUE image_draw_line(int argc, VALUE *argv, VALUE self) {