Implement fill with color

src/main.rs

@@ -1,6 +1,6 @@
 mod image_button;
-mod paint;
 mod mouse_area;
+mod paint;
 
 pub fn main() -> iced::Result {
     paint::main()

src/mouse_area.rs

@@ -1,3 +1,4 @@
+//! code copy from: https://github.com/airstrike/sweeten/blob/master/src/widget/mouse_area.rs
 //! A container for capturing mouse events.
 //!
 //! This is a sweetened version of `iced`'s [`MouseArea`] where all event
@@ -31,17 +32,11 @@ use iced_core::renderer;
 use iced_core::touch;
 use iced_core::widget::{Operation, Tree, tree};
 use iced_core::{
-    Clipboard, Element, Event, Layout, Length, Point, Rectangle, Shell, Size,
-    Vector, Widget,
+    Clipboard, Element, Event, Layout, Length, Point, Rectangle, Shell, Size, Vector, Widget,
 };
 
 /// Emit messages on mouse events.
-pub struct MouseArea<
-    'a,
-    Message,
-    Theme = iced_core::Theme,
-    Renderer = iced::Renderer,
-> {
+pub struct MouseArea<'a, Message, Theme = iced_core::Theme, Renderer = iced::Renderer> {
     content: Element<'a, Message, Theme, Renderer>,
     on_press: Option<Box<dyn Fn(Point) -> Message + 'a>>,
     on_release: Option<Box<dyn Fn(Point) -> Message + 'a>>,
@@ -71,10 +66,7 @@ impl<'a, Message, Theme, Renderer> MouseArea<'a, Message, Theme, Renderer> {
     ///
     /// The closure receives the click position as a [`Point`].
     #[must_use]
-    pub fn on_press_maybe(
-        mut self,
-        f: Option<impl Fn(Point) -> Message + 'a>,
-    ) -> Self {
+    pub fn on_press_maybe(mut self, f: Option<impl Fn(Point) -> Message + 'a>) -> Self {
         self.on_press = f.map(|f| Box::new(f) as _);
         self
     }
@@ -101,10 +93,7 @@ impl<'a, Message, Theme, Renderer> MouseArea<'a, Message, Theme, Renderer> {
     /// [`on_press`]: Self::on_press
     /// [`on_release`]: Self::on_release
     #[must_use]
-    pub fn on_double_click(
-        mut self,
-        f: impl Fn(Point) -> Message + 'a,
-    ) -> Self {
+    pub fn on_double_click(mut self, f: impl Fn(Point) -> Message + 'a) -> Self {
         self.on_double_click = Some(Box::new(f));
         self
     }
@@ -122,10 +111,7 @@ impl<'a, Message, Theme, Renderer> MouseArea<'a, Message, Theme, Renderer> {
     ///
     /// The closure receives the release position as a [`Point`].
     #[must_use]
-    pub fn on_right_release(
-        mut self,
-        f: impl Fn(Point) -> Message + 'a,
-    ) -> Self {
+    pub fn on_right_release(mut self, f: impl Fn(Point) -> Message + 'a) -> Self {
         self.on_right_release = Some(Box::new(f));
         self
     }
@@ -134,10 +120,7 @@ impl<'a, Message, Theme, Renderer> MouseArea<'a, Message, Theme, Renderer> {
     ///
     /// The closure receives the click position as a [`Point`].
     #[must_use]
-    pub fn on_middle_press(
-        mut self,
-        f: impl Fn(Point) -> Message + 'a,
-    ) -> Self {
+    pub fn on_middle_press(mut self, f: impl Fn(Point) -> Message + 'a) -> Self {
         self.on_middle_press = Some(Box::new(f));
         self
     }
@@ -146,20 +129,14 @@ impl<'a, Message, Theme, Renderer> MouseArea<'a, Message, Theme, Renderer> {
     ///
     /// The closure receives the release position as a [`Point`].
     #[must_use]
-    pub fn on_middle_release(
-        mut self,
-        f: impl Fn(Point) -> Message + 'a,
-    ) -> Self {
+    pub fn on_middle_release(mut self, f: impl Fn(Point) -> Message + 'a) -> Self {
         self.on_middle_release = Some(Box::new(f));
         self
     }
 
     /// Sets the message to emit when the scroll wheel is used.
     #[must_use]
-    pub fn on_scroll(
-        mut self,
-        on_scroll: impl Fn(mouse::ScrollDelta) -> Message + 'a,
-    ) -> Self {
+    pub fn on_scroll(mut self, on_scroll: impl Fn(mouse::ScrollDelta) -> Message + 'a) -> Self {
         self.on_scroll = Some(Box::new(on_scroll));
         self
     }
@@ -210,9 +187,7 @@ struct State {
 
 impl<'a, Message, Theme, Renderer> MouseArea<'a, Message, Theme, Renderer> {
     /// Creates a [`MouseArea`] with the given content.
-    pub fn new(
-        content: impl Into<Element<'a, Message, Theme, Renderer>>,
-    ) -> Self {
+    pub fn new(content: impl Into<Element<'a, Message, Theme, Renderer>>) -> Self {
         MouseArea {
             content: content.into(),
             on_press: None,
@@ -232,7 +207,7 @@ impl<'a, Message, Theme, Renderer> MouseArea<'a, Message, Theme, Renderer> {
 }
 
 impl<Message, Theme, Renderer> Widget<Message, Theme, Renderer>
-for MouseArea<'_, Message, Theme, Renderer>
+    for MouseArea<'_, Message, Theme, Renderer>
 where
     Renderer: renderer::Renderer,
 {
@@ -262,11 +237,9 @@ where
         renderer: &Renderer,
         limits: &layout::Limits,
     ) -> layout::Node {
-        self.content.as_widget_mut().layout(
-            &mut tree.children[0],
-            renderer,
-            limits,
-        )
+        self.content
+            .as_widget_mut()
+            .layout(&mut tree.children[0], renderer, limits)
     }
 
     fn operate(
@@ -276,12 +249,9 @@ where
         renderer: &Renderer,
         operation: &mut dyn Operation,
     ) {
-        self.content.as_widget_mut().operate(
-            &mut tree.children[0],
-            layout,
-            renderer,
-            operation,
-        );
+        self.content
+            .as_widget_mut()
+            .operate(&mut tree.children[0], layout, renderer, operation);
     }
 
     fn update(
@@ -330,9 +300,7 @@ where
         );
 
         match (self.interaction, content_interaction) {
-            (Some(interaction), mouse::Interaction::None)
-            if cursor.is_over(layout.bounds()) =>
-                {
+            (Some(interaction), mouse::Interaction::None) if cursor.is_over(layout.bounds()) => {
                 interaction
             }
             _ => content_interaction,
@@ -379,7 +347,7 @@ where
 }
 
 impl<'a, Message, Theme, Renderer> From<MouseArea<'a, Message, Theme, Renderer>>
-for Element<'a, Message, Theme, Renderer>
+    for Element<'a, Message, Theme, Renderer>
 where
     Message: 'a,
     Theme: 'a,
@@ -451,11 +419,8 @@ fn update<Message, Theme, Renderer>(
             if let Some(position) = cursor.position_in(layout.bounds())
                 && let Some(on_double_click) = widget.on_double_click.as_ref()
             {
-                let new_click = mouse::Click::new(
-                    position,
-                    mouse::Button::Left,
-                    state.previous_click,
-                );
+                let new_click =
+                    mouse::Click::new(position, mouse::Button::Left, state.previous_click);
 
                 if new_click.kind() == mouse::click::Kind::Double {
                     shell.publish(on_double_click(position));

src/paint.rs

@@ -1,44 +1,21 @@
+use std::time::Instant;
+
 use iced::Theme;
 use iced::padding;
 use iced::widget::container;
-use iced::widget::{Column, Grid, button, column, image, row, mouse_area};
+use iced::widget::{Column, Grid, button, column, image, row};
 use iced::{Border, Color, Length, Point, Task};
 
-
 use crate::image_button::image_button;
+use crate::mouse_area::mouse_area;
 
 const WIDTH: u32 = 800;
 const HEIGHT: u32 = 600;
 
-struct Paint {
-    tool_states: [bool; Tool::Count as usize],
-    tool_selected: Tool,
-
-    // 原始像素数据：RGBA 格式
-    // 长度 = WIDTH * HEIGHT * 4
-    pixels: Vec<u8>,
-    pixels_bak: Vec<u8>,
-
-    // 当前画笔颜色
-    color: Color,
-
-    // 是否正在绘制
-    is_drawing: bool,
-
-    begin_point: Option<Point>,
-
-    // 用于显示的图像句柄缓存
-    // 每次像素变化后需要重新生成
-    image_handle: image::Handle,
-
-    // 标记像素是否被修改，用于优化图像句柄的生成
-    dirty: bool,
-}
 #[derive(Debug, Clone, Copy)]
 pub enum Message {
-    Decrement,
     MousePressed(Point),
-    MouseReleased,
+    MouseReleased(Point),
     MouseMoved(Point),
     Clear,
     ChangeColor(Color),
@@ -118,6 +95,54 @@ impl From<Tool> for usize {
     }
 }
 
+#[derive(Debug, Clone, Copy, PartialEq)]
+struct ColorU8 {
+    r: u8,
+    g: u8,
+    b: u8,
+    a: u8,
+}
+
+impl ColorU8 {
+    fn new(r: u8, g: u8, b: u8, a: u8) -> Self {
+        Self { r, g, b, a }
+    }
+
+    fn is_same(&self, color: Color) -> bool {
+        self.r == (color.r * 255.0) as u8
+            && self.g == (color.g * 255.0) as u8
+            && self.b == (color.b * 255.0) as u8
+            && self.a == (color.a * 255.0) as u8
+    }
+}
+
+struct Paint {
+    tool_states: [bool; Tool::Count as usize],
+    tool_selected: Tool,
+
+    // 原始像素数据：RGBA 格式
+    // 长度 = WIDTH * HEIGHT * 4
+    pixels: Vec<u8>,
+    pixels_bak: Vec<u8>,
+
+    // 当前画笔颜色
+    color: Color,
+
+    // 是否正在绘制
+    is_drawing: bool,
+
+    begin_point: Point,
+
+    // 用于显示的图像句柄缓存
+    // 每次像素变化后需要重新生成
+    image_handle: image::Handle,
+
+    // brush 大小
+    brush_radius: i32,
+
+    // 标记像素是否被修改，用于优化图像句柄的生成
+    dirty: bool,
+}
 
 impl Paint {
     // region iced application (new view update)
@@ -134,8 +159,9 @@ impl Paint {
             pixels_bak: Vec::new(),
             color: Color::BLACK,
             is_drawing: false,
-            begin_point: None,
+            begin_point: Point::ORIGIN,
             image_handle: image::Handle::from_rgba(WIDTH, HEIGHT, data),
+            brush_radius: 1,
             dirty: false,
         }
     }
@@ -148,8 +174,8 @@ impl Paint {
             .height(Length::Fixed(HEIGHT as f32));
 
         let canvas_area = mouse_area(image_widget)
-            .on_press(Message::MousePressed(Point::ORIGIN)) // 占位，实际逻辑在 on_drag 或自定义
-            .on_release(Message::MouseReleased)
+            .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));
         // 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！
 
@@ -185,13 +211,16 @@ impl Paint {
 
         // We use a column: a simple vertical layout
         column![
-            button("-").on_press(Message::Decrement),
+            button("CLEAR").on_press(Message::Clear),
             row![tool_area, canvas_area],
         ]
     }
 
     pub fn update(&mut self, message: Message) -> Task<Message> {
         match self.tool_selected {
+            Tool::FillWithColor => {
+                self.update_with_fill_with_color(message);
+            }
             Tool::Pencil => {
                 self.update_with_pencil(message);
             }
@@ -239,8 +268,16 @@ impl Paint {
 
     pub fn update_with_fill_with_color(&mut self, message: Message) {
         match message {
-            Message::MousePressed(_pos) => {
-
+            Message::MousePressed(pos) => {
+                // let start = Instant::now();
+                // let (iter_count, fill_count) = self.fill_scanline(pos);
+                // let elapsed = start.elapsed();
+                // println!(
+                //     "fill_scanline: {:?}, iter_count: {iter_count}, fill_count: {fill_count}, ratio: {}",
+                //     elapsed,
+                //     (iter_count as f32 / fill_count as f32)
+                // );
+                self.fill_scanline(pos);
             }
             _ => {}
         }
@@ -248,21 +285,20 @@ impl Paint {
 
     pub fn update_with_pencil(&mut self, message: Message) {
         match message {
-            Message::MousePressed(_pos) => {
+            Message::MousePressed(pos) => {
+                println!("pressed: {:?}", pos);
                 self.is_drawing = true;
+                self.draw_pixel_at1(pos);
+                self.begin_point = pos;
             }
-            Message::MouseReleased => {
+            Message::MouseReleased(pos) => {
                 self.is_drawing = false;
-                self.begin_point = None;
+                self.begin_point = pos;
             }
             Message::MouseMoved(pos) => {
                 if self.is_drawing {
-                    if let Some(begin_point) = self.begin_point {
-                        self.draw_line(begin_point, pos);
-                    } else {
-                        self.draw_pixel_at1(pos);
-                    }
-                    self.begin_point = Some(pos);
+                    self.draw_line(self.begin_point, pos);
+                    self.begin_point = pos;
                 }
             }
             _ => {}
@@ -271,23 +307,19 @@ impl Paint {
 
     pub fn update_with_line(&mut self, message: Message) {
         match message {
-            Message::MousePressed(_pos) => {
+            Message::MousePressed(pos) => {
                 self.is_drawing = true;
                 self.save_pixels();
+                self.begin_point = pos;
             }
-            Message::MouseReleased => {
+            Message::MouseReleased(pos) => {
                 self.is_drawing = false;
-                self.begin_point = None;
-
+                self.begin_point = pos;
             }
             Message::MouseMoved(pos) => {
                 if self.is_drawing {
-                    if let Some(begin_point) = self.begin_point {
                     self.restore_pixels();
-                        self.draw_line(begin_point, pos);
-                    } else {
-                        self.begin_point = Some(pos);
-                    }
+                    self.draw_line(self.begin_point, pos);
                 }
             }
             _ => {}
@@ -320,20 +352,55 @@ impl Paint {
 }
 
 /// draw method
+#[allow(unused)]
 impl Paint {
-    /// 核心绘图逻辑：直接在字节数组上操作
-    fn draw_pixel_at(&mut self, pos: Point<i32>) {
-        let x = pos.x;
-        let y = pos.y;
-
+    fn pixel_at(&self, x: i32, y: i32) -> ColorU8 {
         // 边界检查
         if x < 0 || x >= WIDTH as i32 || y < 0 || y >= HEIGHT as i32 {
-            return;
+            return ColorU8::new(0, 0, 0, 0);
         }
 
         let x = x as u32;
         let y = y as u32;
 
+        let index = ((y * WIDTH + x) * 4) as usize;
+
+        ColorU8::new(
+            self.pixels[index],
+            self.pixels[index + 1],
+            self.pixels[index + 2],
+            self.pixels[index + 3],
+        )
+    }
+
+    fn pixel_at_raw(&self, x: i32, y: i32) -> ColorU8 {
+        let x = x as u32;
+        let y = y as u32;
+        let index = ((y * WIDTH + x) * 4) as usize;
+        ColorU8::new(
+            self.pixels[index],
+            self.pixels[index + 1],
+            self.pixels[index + 2],
+            self.pixels[index + 3],
+        )
+    }
+
+    fn pixel_at1(&self, point: Point) -> ColorU8 {
+        self.pixel_at(point.x as i32, point.y as i32)
+    }
+
+    fn draw_brush_at(&mut self, center_x: i32, center_y: i32) {
+        let r = self.brush_radius;
+        for dy in -r..=r {
+            for dx in -r..=r {
+                if dx * dx + dy * dy <= r * r {
+                    self.draw_pixel_at(center_x + dx, center_y + dy);
+                }
+            }
+        }
+    }
+
+    fn draw_pixel_at_raw(&mut self, x: u32, y: u32) {
         // 计算索引：(y * width + x) * 4
         let index = ((y * WIDTH + x) * 4) as usize;
 
@@ -347,8 +414,39 @@ impl Paint {
         self.dirty = true;
     }
 
+    /// 核心绘图逻辑：直接在字节数组上操作
+    fn draw_pixel_at(&mut self, x: i32, y: i32) {
+        // 边界检查
+        if x < 0 || x >= WIDTH as i32 || y < 0 || y >= HEIGHT as i32 {
+            return;
+        }
+        self.draw_pixel_at_raw(x as u32, y as u32);
+    }
+
+    fn draw_pixel_row(&mut self, xs: i32, xe: i32, y: i32) {
+        if y < 0 || y >= HEIGHT as i32 {
+            return;
+        }
+
+        let xs = xs.clamp(0, WIDTH as i32 - 1) as u32;
+        let xe = xe.clamp(0, WIDTH as i32) as u32;
+        let y = y as u32;
+        for x in xs..xe {
+            let index = ((y * 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] = (self.color.r * 255.0) as u8; // R
+            self.pixels[index + 1] = (self.color.g * 255.0) as u8; // G
+            self.pixels[index + 2] = (self.color.b * 255.0) as u8; // B
+            self.pixels[index + 3] = (self.color.a * 255.0) as u8; // A
+        }
+
+        self.dirty = true;
+    }
+
     fn draw_pixel_at1(&mut self, pos: Point) {
-        self.draw_pixel_at(Point::new(pos.x as i32, pos.y as i32))
+        self.draw_pixel_at(pos.x as i32, pos.y as i32)
     }
 
     fn draw_lines(&mut self, points: &[Point]) {
@@ -369,13 +467,17 @@ impl Paint {
 
     /// Bresenham's line drawing algorithm
     fn draw_line(&mut self, begin: Point, end: Point) {
-        let x1 = begin.x;
-        let y1 = begin.y;
-        let x2 = end.x;
-        let y2 = end.y;
+        let x1 = begin.x as i32;
+        let y1 = begin.y as i32;
+        let x2 = end.x as i32;
+        let y2 = end.y as i32;
 
-        let dx = (x2 - x1) as i32;
-        let dy = (y2 - y1) as i32;
+        // draw start end point, 防止多条线段在连接点出现断开（比如 ab bc）
+        self.draw_pixel_at(x1, y1);
+        self.draw_pixel_at(x2, y2);
+
+        let dx = (x2 - x1);
+        let dy = (y2 - y1);
         let dx1 = dx.abs();
         let dy1 = dy.abs();
         let mut px = 2 * dy1 - dx1;
@@ -388,16 +490,15 @@ impl Paint {
 
         if dy1 <= dx1 {
             if dx >= 0 {
-                x = x1 as i32;
-                y = y1 as i32;
-                xe = x2 as i32;
+                x = x1;
+                y = y1;
+                xe = x2;
             } else {
-                x = x2 as i32;
-                y = y2 as i32;
-                xe = x1 as i32;
+                x = x2;
+                y = y2;
+                xe = x1;
             }
-            let point = Point::new(x, y);
-            self.draw_pixel_at(point);
+            self.draw_pixel_at(x, y);
             while x < xe {
                 x += 1;
                 if px < 0 {
@@ -410,21 +511,19 @@ impl Paint {
                     }
                     px = px + 2 * (dy1 - dx1);
                 }
-                let point = Point::new(x, y);
-                self.draw_pixel_at(point);
+                self.draw_pixel_at(x, y);
             }
         } else {
             if dy >= 0 {
-                x = x1 as i32;
-                y = y1 as i32;
-                ye = y2 as i32;
+                x = x1;
+                y = y1;
+                ye = y2;
             } else {
-                x = x2 as i32;
-                y = y2 as i32;
-                ye = y1 as i32;
+                x = x2;
+                y = y2;
+                ye = y1;
             }
-            let point = Point::new(x, y);
-            self.draw_pixel_at(point);
+            self.draw_pixel_at(x, y);
             while y < ye {
                 y = y + 1;
                 if py <= 0 {
@@ -437,8 +536,7 @@ impl Paint {
                     }
                     py = py + 2 * (dx1 - dy1);
                 }
-                let point = Point::new(x, y);
-                self.draw_pixel_at(point);
+                self.draw_pixel_at(x, y);
             }
         }
     }
@@ -450,6 +548,170 @@ impl Paint {
     fn restore_pixels(&mut self) {
         self.pixels = self.pixels_bak.clone();
     }
+
+    fn fill_slow(&mut self, begin: Point) -> (i32, i32) {
+        let start_x = begin.x as i32;
+        let start_y = begin.y as i32;
+        let target_color = self.pixel_at(start_x, start_y);
+        if target_color.is_same(self.color) {
+            return (0, 0);
+        }
+
+        let mut scan_points = vec![(start_x, start_y)];
+        let width = WIDTH as i32;
+        let height = HEIGHT as i32;
+        let mut iter_count = 0;
+        let mut fill_count = 0;
+        while let Some((x, y)) = scan_points.pop() {
+            iter_count += 1;
+
+            if x < 0 || x >= width || y < 0 || y >= height {
+                continue;
+            }
+            if self.pixel_at_raw(x, y) == target_color {
+                self.draw_pixel_at_raw(x as u32, y as u32);
+                fill_count += 1;
+
+                let p1 = (x - 1, y);
+                let p2 = (x + 1, y);
+                let p3 = (x, y - 1);
+                let p4 = (x, y + 1);
+                scan_points.push(p1);
+                scan_points.push(p2);
+                scan_points.push(p3);
+                scan_points.push(p4);
+            }
+        }
+        (iter_count, fill_count)
+    }
+
+    fn fill_less_slow(&mut self, begin: Point) -> (i32, i32) {
+        let start_x = begin.x as i32;
+        let start_y = begin.y as i32;
+        let width = WIDTH as i32;
+        let height = HEIGHT as i32;
+
+        if start_x < 0 || start_x >= width || start_y < 0 || start_y >= height {
+            return (0, 0);
+        }
+
+        let target_color = self.pixel_at(start_x, start_y);
+        if target_color.is_same(self.color) {
+            return (0, 0);
+        }
+
+        let mut stack = vec![(start_x, start_y)];
+        let mut iter_count = 0;
+        let mut fill_count = 0;
+
+        while let Some((x, y)) = stack.pop() {
+            iter_count += 1;
+
+            if x < 0 || x >= width || y < 0 || y >= height {
+                continue;
+            }
+
+            if self.pixel_at_raw(x, y) != target_color {
+                continue;
+            }
+
+            self.draw_pixel_at_raw(x as u32, y as u32);
+            fill_count += 1;
+
+            // 提前检查边界再入栈
+            if x > 0 {
+                stack.push((x - 1, y));
+            }
+            if x + 1 < width {
+                stack.push((x + 1, y));
+            }
+            if y > 0 {
+                stack.push((x, y - 1));
+            }
+            if y + 1 < height {
+                stack.push((x, y + 1));
+            }
+        }
+
+        (iter_count, fill_count)
+    }
+
+    fn fill_scanline(&mut self, begin: Point) -> (i32, i32) {
+        let start_x = begin.x as i32;
+        let start_y = begin.y as i32;
+        let width = WIDTH as i32;
+        let height = HEIGHT as i32;
+
+        // 边界检查
+        if start_x < 0 || start_x >= width || start_y < 0 || start_y >= height {
+            return (0, 0);
+        }
+
+        let target_color = self.pixel_at(start_x, start_y);
+        if target_color.is_same(self.color) {
+            return (0, 0);
+        }
+
+        // 栈中存储 (y, x1, x2)：表示第 y 行从 x1 到 x2（含）需要向上/下扫描
+        let mut stack = vec![(start_y, start_x, start_x)];
+        let mut iter_count = 0;
+        let mut fill_count = 0;
+
+        while let Some((y, mut lx, mut rx)) = stack.pop() {
+            iter_count += 1;
+
+            // 向左扩展 lx
+            while lx - 1 >= 0 && self.pixel_at_raw(lx - 1, y) == target_color {
+                lx -= 1;
+            }
+            // 向右扩展 rx
+            while rx + 1 < width && self.pixel_at_raw(rx + 1, y) == target_color {
+                rx += 1;
+            }
+
+            // 填充当前行 [lx, rx]
+            for x in lx..=rx {
+                self.draw_pixel_at_raw(x as u32, y as u32);
+                fill_count += 1;
+            }
+
+            // 检查上一行 (y - 1)
+            if y - 1 >= 0 {
+                let mut x = lx;
+                while x <= rx {
+                    if self.pixel_at_raw(x, y - 1) == target_color {
+                        let span_start = x;
+                        // 跳过连续的目标色块
+                        while x <= rx && self.pixel_at_raw(x, y - 1) == target_color {
+                            x += 1;
+                        }
+                        // 将这个 span 入栈（用于后续处理上一行的上一行）
+                        stack.push((y - 1, span_start, x - 1));
+                    } else {
+                        x += 1;
+                    }
+                }
+            }
+
+            // 检查下一行 (y + 1)
+            if y + 1 < height {
+                let mut x = lx;
+                while x <= rx {
+                    if self.pixel_at_raw(x, y + 1) == target_color {
+                        let span_start = x;
+                        while x <= rx && self.pixel_at_raw(x, y + 1) == target_color {
+                            x += 1;
+                        }
+                        stack.push((y + 1, span_start, x - 1));
+                    } else {
+                        x += 1;
+                    }
+                }
+            }
+        }
+
+        (iter_count, fill_count)
+    }
 }
 
 pub fn main() -> iced::Result {