feat: 实现取色功能

src/paint.rs

@@ -87,6 +87,8 @@ enum Message {
     MouseReleased(Point),
     MouseMoved(Point),
     MouseDoubleClick(Point),
+    MouseRightPressed(Point),
+    MouseRightReleased(Point),
 
     Clear,
     SavePNG,
@@ -301,6 +303,7 @@ enum ControlState {
 struct PaintApp {
     tool_states: [bool; Tool::Count as usize],
     tool_selected: Tool,
+    prev_tool_selected: Tool,
 
     /// 画图层
     canvas: MSCanvas,
@@ -352,6 +355,7 @@ impl PaintApp {
         let mut ins = Self {
             tool_states: [false; Tool::Count as usize],
             tool_selected: Tool::Count,
+            prev_tool_selected: Tool::Count,
             canvas,
             view_canvas,
             is_drawing: false,
@@ -377,6 +381,8 @@ impl PaintApp {
             .stroke_color(MSColor::BLACK)
             .line_width(1);
 
+        ins.update_tool_states(Tool::Pencil);
+
         ins
     }
 
@@ -391,7 +397,9 @@ impl PaintApp {
             .on_press(|pos| Message::MousePressed(pos)) // 占位，实际逻辑在 on_drag 或自定义
             .on_release(|pos| Message::MouseReleased(pos))
             .on_move(|pos| Message::MouseMoved(pos))
-            .on_double_click(|pos| Message::MouseDoubleClick(pos));
+            .on_double_click(|pos| Message::MouseDoubleClick(pos))
+            .on_right_press(|pos| Message::MouseRightPressed(pos))
+            .on_right_release(|pos| Message::MouseRightReleased(pos));
         // 注意：mouse_area 的 on_move 给出的坐标通常是相对于 widget 左上角的，这正是我们需要的！
         let canvas_area = container(canvas_area)
             .width(Length::Fill)
@@ -598,6 +606,9 @@ impl PaintApp {
             Tool::FillWithColor => {
                 self.update_with_fill_with_color(message);
             }
+            Tool::PickColor => {
+                self.update_with_pick_color(message);
+            }
             Tool::Pencil => {
                 self.update_with_pencil(message);
             }
@@ -934,6 +945,30 @@ impl PaintApp {
         }
     }
 
+    pub fn update_with_pick_color(&mut self, message: Message) {
+        match message {
+            Message::MousePressed(pos) => {
+                let color_option = self.canvas.pixel_at(pos.x as i32, pos.y as i32);
+                if let Some(color) = color_option {
+                    self.foreground_color = color;
+                    self.canvas.stroke_color(color);
+                    self.canvas.fill_color(color);
+                }
+            }
+            Message::MouseRightPressed(pos) => {
+                let color_option = self.canvas.pixel_at(pos.x as i32, pos.y as i32);
+                if let Some(color) = color_option {
+                    self.background_color = color;
+                }
+            }
+            Message::MouseReleased(_) | Message::MouseRightReleased(_) => {
+                self.update_tool_states(self.prev_tool_selected);
+            }
+
+            _ => {}
+        }
+    }
+
     pub fn update_with_pencil(&mut self, message: Message) {
         match message {
             Message::MousePressed(pos) => {
@@ -1345,6 +1380,7 @@ impl PaintApp {
             self.tool_states[i] = false;
         }
         self.tool_states[idx] = !old_value;
+        self.prev_tool_selected = self.tool_selected;
         self.tool_selected = idx.into();
     }