From d56c5d1229bd1addf9a61deab438105b44e34ac9 Mon Sep 17 00:00:00 2001
From: Yu Chen <yuchen@mail.tsinghua.edu.cn>
Date: Tue, 3 Jan 2023 18:34:45 +0800
Subject: [PATCH] update move_rect Fn

---
 os/src/gui/paint.rs | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/os/src/gui/paint.rs b/os/src/gui/paint.rs
index 0cdf60d3..b96d187b 100644
--- a/os/src/gui/paint.rs
+++ b/os/src/gui/paint.rs
@@ -28,7 +28,14 @@ impl DrawingBoard {
             .draw(&mut self.graphics)
             .ok();
     }
+    fn unpaint(&mut self) {
+        Rectangle::with_center(self.latest_pos, Size::new(RECT_SIZE, RECT_SIZE))
+            .into_styled(PrimitiveStyle::with_stroke(Rgb888::BLACK, 1))
+            .draw(&mut self.graphics)
+            .ok();
+    }
     pub fn move_rect(&mut self, dx: i32, dy: i32) {
+        self.unpaint();
         self.latest_pos.x += dx;
         self.latest_pos.y += dy;
         self.paint();