From 6db8941b675df239e0b8e98507574c2608aa6579 Mon Sep 17 00:00:00 2001
From: yeqing <heopro@163.com>
Date: Fri, 6 Mar 2026 15:39:57 +0800
Subject: [PATCH] =?UTF-8?q?fix:=20=E7=9F=A9=E5=BD=A2=E6=A1=86=E7=A7=BB?=
 =?UTF-8?q?=E5=8A=A8=E5=87=BA=E7=95=8C?=
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---
 src/mscanvas.rs | 46 +++++++++++++++++++++++++++++++++++++---------
 src/paint.rs    | 11 +++++++++--
 2 files changed, 46 insertions(+), 11 deletions(-)

diff --git a/src/mscanvas.rs b/src/mscanvas.rs
index 3859917..551658f 100644
--- a/src/mscanvas.rs
+++ b/src/mscanvas.rs
@@ -68,6 +68,10 @@ impl MSColor {
         let b = n as u8;
         Self { r, g, b, a: 0xff }
     }
+
+    pub fn invert(&self) -> Self {
+        Self::new(255 - self.r, 255 - self.g, 255 - self.b, self.a)
+    }
 }
 
 #[derive(Clone, Copy, PartialEq)]
@@ -1375,18 +1379,42 @@ impl MSCanvas {
     }
 
     pub fn draw_rect_selection(&mut self, x: i32, y: i32, rect: &RectSelection) {
-        let w = rect.w.min(self.width - x);
-        let h = rect.h.min(self.height - y);
+        // 边界检查
+        if x >= self.width || y >= self.height {
+            return;
+        }
+
+        // 考虑矩形四边出界的情况
+        let w = (rect.w as i32).min(self.width - x).min(rect.w + x);
+        let h = (rect.h as i32).min(self.height - y).min(rect.h + y);
+
+        if w == 0 || h == 0 {
+            return;
+        }
+
+        let mut src_offset_x = 0usize;
+        let mut src_offset_y = 0usize;
+        if x < 0 {
+            src_offset_x = (-x) as usize;
+        }
+        if y < 0 {
+            src_offset_y = (-y) as usize;
+        }
+        let x = x.max(0) as usize;
+        let y = y.max(0) as usize;
+        let w = w as usize;
+        let h = h as usize;
+        let width = self.width as usize;
 
         for dy in 0..h {
-            for dx in 0..w {
-                let src_idx = ((dy * rect.w + dx) * 4) as usize;
-                let dst_idx = (((y + dy) * self.width + x + dx) * 4) as usize;
+            let src_start = ((dy + src_offset_y) * rect.w as usize + src_offset_x) * 4;
+            let dst_start = ((y + dy) * width + x) * 4;
 
-                self.pixels[dst_idx] = rect.pixels[src_idx];
-                self.pixels[dst_idx + 1] = rect.pixels[src_idx + 1];
-                self.pixels[dst_idx + 2] = rect.pixels[src_idx + 2];
-                self.pixels[dst_idx + 3] = rect.pixels[src_idx + 3];
+            // 使用 unsafe 块进一步优化（如果确定索引安全）
+            unsafe {
+                let src_slice = &rect.pixels.get_unchecked(src_start..src_start + w * 4);
+                let dst_slice = self.pixels.get_unchecked_mut(dst_start..dst_start + w * 4);
+                dst_slice.copy_from_slice(src_slice);
             }
         }
     }
diff --git a/src/paint.rs b/src/paint.rs
index 21d18c5..b984566 100644
--- a/src/paint.rs
+++ b/src/paint.rs
@@ -394,7 +394,7 @@ impl PaintApp {
             .height(Length::Fixed(height as f32));
 
         let canvas_area = mouse_area(image_widget)
-            .on_press(|pos| Message::MousePressed(pos)) // 占位，实际逻辑在 on_drag 或自定义
+            .on_press(|pos| Message::MousePressed(pos))
             .on_release(|pos| Message::MouseReleased(pos))
             .on_move(|pos| Message::MouseMoved(pos))
             .on_double_click(|pos| Message::MouseDoubleClick(pos))
@@ -811,7 +811,10 @@ impl PaintApp {
                             self.control_state = ControlState::Two;
                         } else {
                             self.release_rect_selection();
-                            self.control_state = ControlState::Zero;
+                            self.is_drawing = true;
+                            self.view_canvas.save_pixels();
+                            self.begin_point = pos;
+                            self.control_state = ControlState::One;
                         }
                     }
                 }
@@ -828,6 +831,10 @@ impl PaintApp {
                         let mut y = p1.y;
                         let mut width = p2.x - p1.x;
                         let mut height = p2.y - p1.y;
+                        if width < 1.0 || height < 1.0 {
+                            self.control_state = ControlState::Zero;
+                            return;
+                        }
                         if width < 0.0 && height < 0.0 {
                             x = p2.x;
                             y = p2.y;