feat: Implement eraser

src/mscanvas.rs

@@ -40,16 +40,15 @@ pub struct MSCanvas {
     width: i32,
     height: i32,
 
-    // 原始像素数据：RGBA 格式
+    /// 原始像素数据：RGBA 格式
-    // 长度 = width * height * 4
+    /// 长度 = width * height * 4
     pixels: Vec<u8>,
     pixels_bak: Vec<u8>,
 
-    // 当前笔画颜色
+    /// 当前笔画颜色
     color: MSColor,
 
-    // brush 大小
+    line_width: i32,
-    brush_radius: f32,
 }
 
 #[allow(unused)]
@@ -61,7 +60,7 @@ impl MSCanvas {
             pixels: vec![255; (width * height * 4) as usize],
             pixels_bak: Vec::new(),
             color: MSColor::BLACK,
-            brush_radius: 0.5,
+            line_width: 1,
         }
     }
 
@@ -69,13 +68,17 @@ impl MSCanvas {
         self.color = color;
     }
 
-    pub fn set_brush_radius(&mut self, brush_radius: f32) {
+    pub fn set_line_width(&mut self, line_width: i32) {
-        self.brush_radius = brush_radius;
+        self.line_width = line_width;
     }
 }
 
 #[allow(unused)]
 impl MSCanvas {
+    pub fn size(&self) -> (i32, i32) {
+        (self.width, self.height)
+    }
+
     pub fn get_pixels(&self) -> Vec<u8> {
         self.pixels.clone()
     }
@@ -157,15 +160,16 @@ impl MSCanvas {
         }
     }
 
-    pub fn draw_brush_at(&mut self, center: Point) {
+    pub fn brush_circle(&mut self, center: Point) {
-        if self.brush_radius < 1.0 {
+        if self.line_width <= 1 {
             self.draw_pixel_at(center);
             return;
         }
-        let square = self.brush_radius * self.brush_radius;
+        let square = (self.line_width as f32) * (self.line_width as f32) / 4.0;
-        let r = self.brush_radius.floor() as i32;
+        let l = self.line_width / 2;
-        for dy in -r..=r {
+        let r = self.line_width - l;
-            for dx in -r..=r {
+        for dy in -l..r {
+            for dx in -l..r {
                 if (dx * dx + dy * dy) as f32 <= square {
                     self.draw_pixel_at(Point::new(center.x + dx as f32, center.y + dy as f32));
                 }
@@ -173,6 +177,20 @@ impl MSCanvas {
         }
     }
 
+    pub fn brush_square(&mut self, center: Point) {
+        if self.line_width <= 1 {
+            self.draw_pixel_at(center);
+            return;
+        }
+        let l = self.line_width / 2;
+        let r = self.line_width - l;
+        for dy in -l..r {
+            for dx in -l..r {
+                self.draw_pixel_at(Point::new(center.x + dx as f32, center.y + dy as f32));
+            }
+        }
+    }
+
     fn bresenham_line(&mut self, begin: Point, end: Point) -> Vec<Point> {
         let x1 = begin.x;
         let y1 = begin.y;
@@ -259,10 +277,25 @@ impl MSCanvas {
         }
     }
 
-    pub fn draw_line_thick(&mut self, begin: Point, end: Point) {
+    pub fn draw_line_with_circle_brush(&mut self, begin: Point, end: Point) {
+        // let points = self.bresenham_line(begin, end);
+        // for point in points {
+        //     self.draw_brush_at(point);
+        // }
+        self.draw_line_with(begin, end, MSCanvas::brush_circle);
+    }
+
+    pub fn draw_line_with_square_brush(&mut self, begin: Point, end: Point) {
+        self.draw_line_with(begin, end, MSCanvas::brush_square);
+    }
+
+    pub fn draw_line_with<F>(&mut self, begin: Point, end: Point, brush_fn: F)
+    where
+        F: Fn(&mut MSCanvas, Point) -> (),
+    {
         let points = self.bresenham_line(begin, end);
         for point in points {
-            self.draw_brush_at(point);
+            brush_fn(self, point);
         }
     }
 
@@ -387,22 +420,65 @@ impl MSCanvas {
         (iter_count, fill_count)
     }
 
-    pub fn stroke_rect(&mut self, x: f32, y: f32, width: f32, height: f32) {
+    pub fn clear_rect(&mut self, x: i32, y: i32, width: i32, height: i32) {
-        self.draw_line_thick(Point::new(x, y), Point::new(x, y + height));
+        for yi in y..(y + height) {
-        self.draw_line_thick(Point::new(x, y + height), Point::new(x + width, y + height));
+            self.clear_row(x, x + width, yi);
-        self.draw_line_thick(Point::new(x + width, y + height), Point::new(x + width, y));
+        }
-        self.draw_line_thick(Point::new(x, y), Point::new(x + width, y));
     }
 
-    pub fn stroke_rect1(&mut self, left_top: Point, right_bottom: Point) {
+    pub fn fill_rect(&mut self, x: i32, y: i32, width: i32, height: i32) {
-        let x = left_top.x;
+        for yi in y..(y + height) {
-        let y = left_top.y;
+            self.draw_pixel_row(x, x + width, yi);
-        let width = (right_bottom.x - left_top.x);
+        }
-        let height = (right_bottom.y - left_top.y);
+    }
-        self.stroke_rect(x, y, width, height);
+
+    pub fn stroke_rect(&mut self, x: i32, y: i32, width: i32, height: i32) {
+        self.fill_rect(x, y, width, self.line_width);
+        self.fill_rect(x, y + height - self.line_width, width, self.line_width);
+        self.fill_rect(x, y, self.line_width, height);
+        self.fill_rect(x + width - self.line_width, y, self.line_width, height);
+    }
+
+    pub fn stroke_rect1(&mut self, p1: Point, p2: Point) {
+        let mut x = p1.x;
+        let mut y = p1.y;
+        let mut width = (p2.x - p1.x);
+        let mut height = (p2.y - p1.y);
+        if width < 0.0 && height < 0.0 {
+            x = p2.x;
+            y = p2.y;
+            width = (p1.x - p2.x);
+            height = (p1.y - p2.y);
+        } else if width < 0.0 {
+            x += width;
+            width = -width;
+        } else if height < 0.0 {
+            y += height;
+            height = -height;
+        }
+        self.stroke_rect(x as i32, y as i32, width as i32, height as i32);
     }
 
     pub fn clear(&mut self) {
         self.pixels.fill(255);
     }
+
+    pub fn clear_row(&mut self, xs: i32, xe: i32, y: i32) {
+        if y < 0 || y >= self.height {
+            return;
+        }
+
+        let xs = xs.clamp(0, self.width - 1);
+        let xe = xe.clamp(0, self.width as i32);
+        for x in xs..xe {
+            let index = ((y * self.width + x) * 4) as usize;
+
+            // 写入 RGBA 数据
+            // 注意：Color 的 r, g, b, a 是 0.0 - 1.0，需要转为 0 - 255
+            self.pixels[index] = 255; // R
+            self.pixels[index + 1] = 255; // G
+            self.pixels[index + 2] = 255; // B
+            self.pixels[index + 3] = 255; // A
+        }
+    }
 }

src/paint.rs

@@ -3,7 +3,7 @@ use crate::mouse_area::mouse_area;
 use iced::Theme;
 use iced::padding;
 use iced::widget::container;
-use iced::widget::{Column, button, column, image, row, text};
+use iced::widget::{Column, button, column, image, pick_list, row, text};
 use iced::{Border, Color, Element, Length, Point, Renderer, Task};
 use iced_core::color;
 
@@ -12,8 +12,41 @@ use crate::mscanvas::MSCanvas;
 const WIDTH: u32 = 800;
 const HEIGHT: u32 = 600;
 
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Default)]
+enum BrushKind {
+    #[default]
+    Circle,
+    Square,
+    Slash,
+    Backslash,
+}
+
+impl BrushKind {
+    const ALL: [BrushKind; 4] = [
+        BrushKind::Circle,
+        BrushKind::Square,
+        BrushKind::Slash,
+        BrushKind::Backslash,
+    ];
+}
+
+impl std::fmt::Display for BrushKind {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        write!(
+            f,
+            "{}",
+            match self {
+                BrushKind::Circle => "Circle",
+                BrushKind::Square => "Square",
+                BrushKind::Slash => "Slash",
+                BrushKind::Backslash => "Backslash",
+            }
+        )
+    }
+}
+
 #[derive(Debug, Clone, Copy)]
-pub enum Message {
+enum Message {
     MousePressed(Point),
     MouseReleased(Point),
     MouseMoved(Point),
@@ -23,12 +56,14 @@ pub enum Message {
 
     ClickTool(Tool),
 
-    Increment,
+    Increment(ConfigOption),
-    Decrement,
+    Decrement(ConfigOption),
+
+    BrushSelected(BrushKind),
 }
 
 #[derive(Clone, Copy, Debug)]
-pub enum Tool {
+enum Tool {
     FreeFormSelect,
     Select,
     Eraser,
@@ -97,6 +132,47 @@ impl From<Tool> for usize {
     }
 }
 
+#[derive(Debug, Clone, Copy, PartialEq)]
+pub enum ConfigOption {
+    EraserWidth,
+    LineWidth,
+}
+
+#[derive(Debug, Clone, Copy)]
+struct Config {
+    eraser_width: i32,
+    line_width: i32,
+}
+
+impl Default for Config {
+    fn default() -> Self {
+        Self::DEFAULT.clone()
+    }
+}
+
+impl Config {
+    const DEFAULT: Config = Config {
+        line_width: 1,
+        eraser_width: 4,
+    };
+    fn incr(&mut self, option: ConfigOption, step: i32) {
+        match option {
+            ConfigOption::EraserWidth => {
+                self.eraser_width += step;
+                if self.eraser_width < Self::DEFAULT.eraser_width {
+                    self.eraser_width = Self::DEFAULT.eraser_width;
+                }
+            }
+            ConfigOption::LineWidth => {
+                self.line_width += step;
+                if self.line_width < Self::DEFAULT.line_width {
+                    self.line_width = Self::DEFAULT.line_width;
+                }
+            }
+        }
+    }
+}
+
 struct PaintApp {
     tool_states: [bool; Tool::Count as usize],
     tool_selected: Tool,
@@ -115,34 +191,39 @@ struct PaintApp {
     // 标记像素是否被修改，用于优化图像句柄的生成
     dirty: bool,
 
-    value: i32,
+    config: Config,
+
+    brush_selected: Option<BrushKind>,
 }
 
 impl PaintApp {
     // region iced application (new view update)
 
     pub fn new() -> Self {
-        let canvas = MSCanvas::new(WIDTH as i32, HEIGHT as i32);
+        let mut canvas = MSCanvas::new(WIDTH as i32, HEIGHT as i32);
+        let (width, height) = canvas.size();
         let pixels = canvas.get_pixels();
+        let config = Config::default();
+        canvas.set_line_width(config.line_width);
         Self {
             tool_states: [false; Tool::Count as usize],
             tool_selected: Tool::Count,
             canvas,
             is_drawing: false,
             begin_point: Point::ORIGIN,
-            image_handle: image::Handle::from_rgba(WIDTH, HEIGHT, pixels),
+            image_handle: image::Handle::from_rgba(width as u32, height as u32, pixels),
             dirty: false,
-
+            config,
-            value: 1,
+            brush_selected: None,
         }
     }
 
     pub fn view(&self) -> Column<'_, Message> {
         // 创建显示图像的 Widget
-        // 如果 handle 还没准备好，显示一个占位符
+        let (width, height) = self.canvas.size();
         let image_widget = image(self.image_handle.clone())
-            .width(Length::Fixed(WIDTH as f32))
+            .width(Length::Fixed(width as f32))
-            .height(Length::Fixed(HEIGHT as f32));
+            .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
@@ -207,24 +288,39 @@ impl PaintApp {
                 }
             });
 
-        let debug_area = column![
+        let mut debug_area = column![
-            text("brush"),
+            text("Eraser Width"),
             row![
-                button("+").on_press(Message::Increment),
+                button("+").on_press(Message::Increment(ConfigOption::EraserWidth)),
-                text(self.value),
+                text(self.config.eraser_width).size(20).center(),
-                button("-").on_press(Message::Decrement),
+                button("-").on_press(Message::Decrement(ConfigOption::EraserWidth)),
-            ]
+            ],
+            text("Line Width"),
+            row![
+                button("+").on_press(Message::Increment(ConfigOption::LineWidth)),
+                text(self.config.line_width).size(20).center(),
+                button("-").on_press(Message::Decrement(ConfigOption::LineWidth)),
+            ],
+            pick_list(
+                &BrushKind::ALL[..],
+                self.brush_selected,
+                Message::BrushSelected,
+            )
+            .placeholder("Brush..."),
         ];
+        debug_area = debug_area.padding(padding::left(5).right(5));
 
         column![
             button("CLEAR").on_press(Message::Clear),
-            row![tool_area, canvas_area],
+            row![tool_area, canvas_area, debug_area],
-            debug_area,
         ]
     }
 
     pub fn update(&mut self, message: Message) -> Task<Message> {
         match self.tool_selected {
+            Tool::Eraser => {
+                self.update_with_eraser(message);
+            }
             Tool::FillWithColor => {
                 self.update_with_fill_with_color(message);
             }
@@ -255,16 +351,17 @@ impl PaintApp {
             Message::ClickTool(tool) => {
                 self.update_tool_states(tool);
             }
-            Message::Increment => {
+            Message::Increment(opt) => {
-                self.value = self.value + 1;
+                self.config.incr(opt, 1);
-                self.canvas.set_brush_radius(self.value as f32 / 2.0);
+                if opt == ConfigOption::LineWidth {
+                    self.canvas.set_line_width(self.config.line_width);
                 }
-            Message::Decrement => {
-                self.value = self.value - 1;
-                if self.value < 1 {
-                    self.value = 1;
             }
-                self.canvas.set_brush_radius(self.value as f32 / 2.0);
+            Message::Decrement(opt) => {
+                self.config.incr(opt, 1);
+                if opt == ConfigOption::LineWidth {
+                    self.canvas.set_line_width(self.config.line_width);
+                }
             }
             _ => {}
         }
@@ -284,6 +381,36 @@ impl PaintApp {
 
     // region tool update
 
+    pub fn update_with_eraser(&mut self, message: Message) {
+        match message {
+            Message::MousePressed(pos) => {
+                self.is_drawing = true;
+                self.canvas.clear_rect(
+                    (pos.x as i32) - self.config.eraser_width / 2,
+                    (pos.y as i32) - self.config.eraser_width / 2,
+                    self.config.eraser_width,
+                    self.config.eraser_width,
+                );
+                self.dirty = true;
+            }
+            Message::MouseReleased(_) => {
+                self.is_drawing = false;
+            }
+            Message::MouseMoved(pos) => {
+                if self.is_drawing {
+                    self.canvas.clear_rect(
+                        (pos.x as i32) - self.config.eraser_width / 2,
+                        (pos.y as i32) - self.config.eraser_width / 2,
+                        self.config.eraser_width,
+                        self.config.eraser_width,
+                    );
+                    self.dirty = true;
+                }
+            }
+            _ => {}
+        }
+    }
+
     pub fn update_with_fill_with_color(&mut self, message: Message) {
         match message {
             Message::MousePressed(pos) => {
@@ -320,7 +447,7 @@ impl PaintApp {
         match message {
             Message::MousePressed(pos) => {
                 self.is_drawing = true;
-                self.canvas.draw_brush_at(pos);
+                self.canvas.brush_circle(pos);
                 self.canvas.save_pixels();
                 self.begin_point = pos;
                 self.dirty = true;
@@ -332,7 +459,8 @@ impl PaintApp {
             Message::MouseMoved(pos) => {
                 if self.is_drawing {
                     self.canvas.restore_pixels();
-                    self.canvas.draw_line_thick(self.begin_point, pos);
+                    self.canvas
+                        .draw_line_with_circle_brush(self.begin_point, pos);
                     self.dirty = true;
                 }
             }