message: fixed canvas_subframe example to adapt to the new behavior of DrawParam on Canvas
diff: @@ -99,8 +99,7 @@ impl event::EventHandler for MainState {
  if self.draw_pt.x + (w as f32 / 2.0) > (w as f32) || self.draw_pt.x < 0.0 {
  self.draw_vec.x *= -1.0;
  }
  - if self.draw_pt.y + (h as f32 / 2.0) > (h as f32 / 2.0)
  - || self.draw_pt.y < -(h as f32 / 2.0)
  + if self.draw_pt.y + (h as f32 / 2.0) > (h as f32) || self.draw_pt.y < 0.0
  {
  self.draw_vec.y *= -1.0;
  }
  @@ -119,7 +118,7 @@ impl event::EventHandler for MainState {
  &self.canvas,
  graphics::DrawParam::new()
  .dest(self.draw_pt)
  - .src(graphics::Rect::new(src_x, -src_y, 0.5, 0.5)),
  + .src(graphics::Rect::new(src_x, src_y, 0.5, 0.5)),
  )?;
  graphics::present(ctx)?;
  Ok(())
  