mspaint/src/mscanvas.rs

use iced::{Color, Point};
use rand::prelude::*;

#[derive(Debug, Clone, Copy, PartialEq)]
pub struct MSColor {
    r: u8,
    g: u8,
    b: u8,
    a: u8,
}

#[allow(unused)]
impl MSColor {
    fn new(r: u8, g: u8, b: u8, a: u8) -> Self {
        Self { r, g, b, a }
    }

    pub const ZERO: MSColor = MSColor {
        r: 0,
        g: 0,
        b: 0,
        a: 0,
    };

    pub const BLACK: MSColor = MSColor {
        r: 0,
        g: 0,
        b: 0,
        a: 255,
    };

    pub const WHITE: MSColor = MSColor {
        r: 255,
        g: 255,
        b: 255,
        a: 255,
    };

    pub const RED: MSColor = MSColor {
        r: 255,
        g: 0,
        b: 0,
        a: 255,
    };

    pub const GREEN: MSColor = MSColor {
        r: 0,
        g: 255,
        b: 0,
        a: 255,
    };

    pub const BLUE: MSColor = MSColor {
        r: 0,
        g: 0,
        b: 255,
        a: 255,
    };

    pub fn into_color(self) -> Color {
        Color::from_rgba8(self.r, self.g, self.b, (self.a / 255) as f32)
    }

    /// rgb 十六进制
    pub fn from_hex(n: i32) -> Self {
        let r = (n >> 16) as u8;
        let g = (n >> 8) as u8;
        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)]
struct Edge {
    y_max: i32, // 边的最大 y（不包含）
    x: f32,     // 当前扫描线 y 处的 x 值
    dx_dy: f32, // 1 / slope = Δx / Δy
}

impl Edge {
    fn new(p1: Point, p2: Point) -> Option<Self> {
        // 确保 p1.y <= p2.y
        let (top, bottom) = if p1.y < p2.y { (p1, p2) } else { (p2, p1) };

        // 忽略水平边（不会贡献交点）
        if (top.y - bottom.y).abs() < f32::EPSILON {
            return None;
        }

        let dx = bottom.x - top.x;
        let dy = bottom.y - top.y;
        let dx_dy = dx / dy;

        Some(Edge {
            y_max: bottom.y as i32,
            x: top.x,
            dx_dy,
        })
    }
}

pub struct Path2D {
    points: Vec<Point>,
}

impl Path2D {
    pub fn new() -> Self {
        Self { points: vec![] }
    }

    pub fn push(&mut self, point: Point) {
        self.points.push(point);
    }
}

pub struct RectSelection {
    /// 左上角坐标
    x: i32,
    y: i32,
    w: i32,
    h: i32,
    pixels: Vec<u8>,
}

impl RectSelection {
    pub fn new(x: i32, y: i32, w: i32, h: i32, pixels: Vec<u8>) -> RectSelection {
        Self { x, y, w, h, pixels }
    }

    pub fn contains(&self, p: Point) -> bool {
        let x = p.x as i32;
        let y = p.y as i32;
        !(x < self.x || y < self.y || x >= self.x + self.w || y >= self.y + self.h)
    }

    pub fn move_offset(&mut self, offset_x: i32, offset_y: i32) {
        self.x += offset_x;
        self.y += offset_y;
    }

    pub fn size(&self) -> (i32, i32) {
        (self.w, self.h)
    }

    pub fn position(&self) -> (i32, i32) {
        (self.x, self.y)
    }
}

pub struct MSCanvas {
    width: i32,
    height: i32,

    /// 原始像素数据：RGBA 格式
    /// 长度 = width * height * 4
    pixels: Vec<u8>,
    pixels_bak: Vec<u8>,

    fill_color: MSColor,
    stroke_color: MSColor,

    line_width: i32,

    path2d: Path2D,
}

#[allow(unused)]
impl MSCanvas {
    pub fn new(width: i32, height: i32) -> Self {
        Self {
            width,
            height,
            pixels: vec![255; (width * height * 4) as usize],
            pixels_bak: Vec::new(),
            fill_color: MSColor::BLACK,
            stroke_color: MSColor::WHITE,
            line_width: 1,
            path2d: Path2D::new(),
        }
    }

    pub fn line_width(&mut self, line_width: i32) -> &mut Self {
        self.line_width = line_width;
        self
    }

    pub fn fill_color(&mut self, color: MSColor) -> &mut Self {
        self.fill_color = color;
        self
    }

    pub fn stroke_color(&mut self, color: MSColor) -> &mut Self {
        self.stroke_color = color;
        self
    }
    pub fn size(&self) -> (i32, i32) {
        (self.width, self.height)
    }

    pub fn get_pixels_ref(&self) -> &[u8] {
        &self.pixels
    }

    pub fn get_pixels(&self) -> Vec<u8> {
        self.pixels.clone()
    }

    pub fn get_pixels_scale(&self, scale: i32) -> Vec<u8> {
        if scale <= 1 {
            return self.pixels.clone();
        }
        let dst_width = self.width * scale;
        let dst_height = self.height * scale;
        let mut dst = vec![0; (dst_width * dst_height * 4) as usize]; // RGBA

        for y in 0..self.height {
            for x in 0..self.width {
                // 源像素索引
                let src_idx = ((y * self.width + x) * 4) as usize;

                // 源像素颜色
                let r = self.pixels[src_idx];
                let g = self.pixels[src_idx + 1];
                let b = self.pixels[src_idx + 2];
                let a = self.pixels[src_idx + 3];

                // 在目标图像中填充 scale×scale 区域
                for dy in 0..scale {
                    for dx in 0..scale {
                        let dst_x = x * scale + dx;
                        let dst_y = y * scale + dy;
                        let dst_idx = ((dst_y * dst_width + dst_x) * 4) as usize;

                        dst[dst_idx] = r;
                        dst[dst_idx + 1] = g;
                        dst[dst_idx + 2] = b;
                        dst[dst_idx + 3] = a;
                    }
                }
            }
        }

        dst
    }

    pub fn pixel_at(&self, x: i32, y: i32) -> Option<MSColor> {
        // 边界检查
        if x < 0 || x >= self.width || y < 0 || y >= self.height {
            return None;
        }

        let index = ((y * self.width + x) * 4) as usize;

        Some(MSColor::new(
            self.pixels[index],
            self.pixels[index + 1],
            self.pixels[index + 2],
            self.pixels[index + 3],
        ))
    }

    pub fn pixel_is(&self, x: i32, y: i32, color: MSColor) -> bool {
        match self.pixel_at(x, y) {
            Some(c) => c == color,
            None => false,
        }
    }

    pub fn select_rect(&self, x: i32, y: i32, w: i32, h: i32) -> RectSelection {
        let mut result = vec![255; (w * h * 4) as usize];

        let mut index = 0;
        for yi in y..(y + h) {
            for xi in x..(x + w) {
                let color = self.pixel_at(xi, yi).unwrap_or(MSColor::WHITE);
                result[index] = color.r;
                result[index + 1] = color.g;
                result[index + 2] = color.b;
                result[index + 3] = color.a;
                index += 4;
            }
        }

        RectSelection::new(x, y, w, h, result)
    }

    pub fn overlay_pixels(&mut self, canvas: &MSCanvas) -> Vec<u8> {
        let mut pixels = canvas.get_pixels();
        let width = canvas.width.min(self.width) as usize;
        let height = canvas.height.min(self.height) as usize;

        let src_stride = self.width as usize * 4;
        let dst_stride = canvas.width as usize * 4; // ⚠️ Bug fix: use canvas.width, not `width`

        for y in 0..height {
            let src_row = &self.pixels[y * src_stride..y * src_stride + width * 4];
            let dst_row = &mut pixels[y * dst_stride..y * dst_stride + width * 4];

            // Process 4 pixels at a time (16 bytes) for better auto-vectorization
            let chunks = width / 4;
            let remainder = width % 4;

            for chunk in 0..chunks {
                let base = chunk * 16;
                // Check alpha bytes for 4 pixels at once
                let a0 = src_row[base + 3];
                let a1 = src_row[base + 7];
                let a2 = src_row[base + 11];
                let a3 = src_row[base + 15];

                if a0 | a1 | a2 | a3 != 0 {
                    // At least one pixel is non-transparent
                    if a0 != 0 && a1 != 0 && a2 != 0 && a3 != 0 {
                        // All 4 pixels are non-transparent — bulk copy 16 bytes
                        dst_row[base..base + 16].copy_from_slice(&src_row[base..base + 16]);
                    } else {
                        // Mixed — copy individually
                        for i in 0..4 {
                            let off = base + i * 4;
                            if src_row[off + 3] != 0 {
                                dst_row[off..off + 4].copy_from_slice(&src_row[off..off + 4]);
                            }
                        }
                    }
                }
                // else: all 4 transparent — skip entirely
            }

            // Handle remaining pixels
            for x in (chunks * 4)..width {
                let off = x * 4;
                if src_row[off + 3] != 0 {
                    dst_row[off..off + 4].copy_from_slice(&src_row[off..off + 4]);
                }
            }
        }

        pixels
    }
}

#[allow(unused)]
impl MSCanvas {
    pub fn fill_pixel_at(&mut self, point: Point) {
        let Point { x, y } = point;
        self.fill_pixel_at1(x as i32, y as i32);
    }

    pub fn stroke_pixel_at(&mut self, point: Point) {
        let Point { x, y } = point;
        self.stroke_pixel_at1(x as i32, y as i32);
    }

    fn fill_pixel_at1(&mut self, x: i32, y: i32) {
        // 边界检查
        if x < 0 || x >= self.width || y < 0 || y >= self.height {
            return;
        }
        // 计算索引：(y * width + x) * 4
        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] = self.fill_color.r; // R
        self.pixels[index + 1] = self.fill_color.g; // G
        self.pixels[index + 2] = self.fill_color.b; // B
        self.pixels[index + 3] = self.fill_color.a; // A
    }

    fn stroke_pixel_at1(&mut self, x: i32, y: i32) {
        // 边界检查
        if x < 0 || x >= self.width || y < 0 || y >= self.height {
            return;
        }
        // 计算索引：(y * width + x) * 4
        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] = self.stroke_color.r; // R
        self.pixels[index + 1] = self.stroke_color.g; // G
        self.pixels[index + 2] = self.stroke_color.b; // B
        self.pixels[index + 3] = self.stroke_color.a; // A
    }

    fn draw_column_with_color(&mut self, ys: i32, ye: i32, x: i32, color: MSColor) {
        if x < 0 || x >= self.width {
            return;
        }

        let ys = ys.clamp(0, self.height - 1);
        let ye = ye.clamp(0, self.height);
        for y in ys..ye {
            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] = color.r; // R
            self.pixels[index + 1] = color.g; // G
            self.pixels[index + 2] = color.b; // B
            self.pixels[index + 3] = color.a; // A
        }
    }

    fn draw_row_with_color(&mut self, xs: i32, xe: i32, y: i32, color: MSColor) {
        if y < 0 || y >= self.height {
            return;
        }

        let xs = xs.clamp(0, self.width - 1);
        let xe = xe.clamp(0, self.width);
        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] = color.r; // R
            self.pixels[index + 1] = color.g; // G
            self.pixels[index + 2] = color.b; // B
            self.pixels[index + 3] = color.a; // A
        }
    }

    fn fill_column(&mut self, ys: i32, ye: i32, x: i32) {
        self.draw_column_with_color(ys, ye, x, self.fill_color);
    }

    fn fill_row(&mut self, xs: i32, xe: i32, y: i32) {
        self.draw_row_with_color(xs, xe, y, self.fill_color);
    }

    fn stroke_column(&mut self, ys: i32, ye: i32, x: i32) {
        self.draw_column_with_color(ys, ye, x, self.stroke_color);
    }

    fn stroke_row(&mut self, xs: i32, xe: i32, y: i32) {
        self.draw_row_with_color(xs, xe, y, self.stroke_color);
    }

    pub fn fill_pixels(&mut self, points: Vec<Point>) {
        for point in points {
            self.fill_pixel_at(point);
        }
    }

    pub fn fill_pixels_i32(&mut self, points: Vec<Point<i32>>) {
        for point in points {
            self.fill_pixel_at1(point.x, point.y);
        }
    }

    pub fn stroke_cross(&mut self, point: Point) {
        let Point { x, y } = point;
        let r = 10;
        for dy in -r..=r {
            self.stroke_pixel_at(Point::new(point.x, point.y + dy as f32));
        }
        for dx in -r..=r {
            self.stroke_pixel_at(Point::new(point.x + dx as f32, point.y));
        }
    }

    pub fn brush_circle(&mut self, center: Point) {
        if self.line_width <= 1 {
            self.fill_pixel_at(center);
            return;
        }
        let square = (self.line_width as f32) * (self.line_width as f32) / 4.0;
        let l = self.line_width / 2;
        let r = self.line_width - l;
        for dy in -l..r {
            for dx in -l..r {
                if (dx * dx + dy * dy) as f32 <= square {
                    self.fill_pixel_at(Point::new(center.x + dx as f32, center.y + dy as f32));
                }
            }
        }
    }

    pub fn brush_square(&mut self, center: Point) {
        if self.line_width <= 1 {
            self.fill_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.fill_pixel_at(Point::new(center.x + dx as f32, center.y + dy as f32));
            }
        }
    }

    pub fn brush_slash(&mut self, center: Point) {
        let r = self.line_width / 2;
        let l = self.line_width - r;
        // 左右扩展，填补线条的空白
        for dx in 0..2 {
            for d in -l..r {
                self.fill_pixel_at(Point::new(
                    center.x - (d as f32) + (dx as f32),
                    center.y - d as f32,
                ));
            }
        }
    }

    pub fn brush_backslash(&mut self, center: Point) {
        let r = self.line_width / 2;
        let l = self.line_width - r;
        // 左右扩展，填补线条的空白
        for dx in 0..2 {
            for d in -l..r {
                self.fill_pixel_at(Point::new(
                    center.x + d as f32 + (dx as f32),
                    center.y - d as f32,
                ));
            }
        }
    }

    fn bresenham_line(&mut self, begin: Point, end: Point) -> Vec<Point> {
        let x1 = begin.x;
        let y1 = begin.y;
        let x2 = end.x;
        let y2 = end.y;

        let dx = (x2 - x1);
        let dy = (y2 - y1);
        let dx1 = dx.abs();
        let dy1 = dy.abs();
        let mut px = 2.0 * dy1 - dx1;
        let mut py = 2.0 * dx1 - dy1;

        let mut x;
        let mut y;
        let xe;
        let ye;

        let mut points = Vec::new();
        if dy1 <= dx1 {
            if dx >= 0.0 {
                x = x1;
                y = y1;
                xe = x2;
                ye = y2;
            } else {
                x = x2;
                y = y2;
                xe = x1;
                ye = y1;
            }
            points.push(Point::new(x, y));
            while x < xe {
                x += 1.0;
                if px < 0.0 {
                    px = px + 2.0 * dy1;
                } else {
                    if (dx < 0.0 && dy < 0.0) || (dx > 0.0 && dy > 0.0) {
                        y = y + 1.0;
                    } else {
                        y = y - 1.0;
                    }
                    px = px + 2.0 * (dy1 - dx1);
                }
                points.push(Point::new(x, y));
            }
        } else {
            if dy >= 0.0 {
                x = x1;
                y = y1;
                ye = y2;
                xe = x2;
            } else {
                x = x2;
                y = y2;
                ye = y1;
                xe = x1;
            }
            points.push(Point::new(x, y));
            while y < ye {
                y = y + 1.0;
                if py <= 0.0 {
                    py = py + 2.0 * dx1;
                } else {
                    if (dx < 0.0 && dy < 0.0) || (dx > 0.0 && dy > 0.0) {
                        x = x + 1.0;
                    } else {
                        x = x - 1.0;
                    }
                    py = py + 2.0 * (dx1 - dy1);
                }
                points.push(Point::new(x, y));
            }
        }
        points.push(Point::new(xe, ye));

        points
    }

    pub fn draw_line(&mut self, begin: Point, end: Point) {
        let points = self.bresenham_line(begin, end);
        for point in points {
            self.fill_pixel_at(point);
        }
    }

    pub fn draw_line_with_circle_brush(&mut self, begin: Point, end: 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 {
            brush_fn(self, point);
        }
    }

    pub fn save_pixels(&mut self) {
        self.pixels_bak = self.pixels.clone();
    }

    pub fn restore_pixels(&mut self) {
        self.pixels = self.pixels_bak.clone();
    }

    pub fn fill_slow(&mut self, begin: Point) {
        let start_x = begin.x as i32;
        let start_y = begin.y as i32;
        let target_color = self.pixel_at(start_x, start_y).unwrap_or(MSColor::ZERO);
        if target_color == self.fill_color {
            return;
        }

        let mut scan_points = vec![(start_x, start_y)];
        let width = self.width;
        let height = self.height;
        while let Some((x, y)) = scan_points.pop() {
            if x < 0 || x >= self.width || y < 0 || y >= self.height {
                continue;
            }
            if self.pixel_is(x, y, target_color) {
                self.fill_pixel_at1(x, y);

                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);
            }
        }
    }

    pub fn fill_scanline(&mut self, begin: Point) {
        let start_x = begin.x as i32;
        let start_y = begin.y as i32;
        let width = self.width;
        let height = self.height;

        // 边界检查
        if start_x < 0 || start_x >= width || start_y < 0 || start_y >= height {
            return;
        }

        let target_color = self.pixel_at(start_x, start_y).unwrap_or(MSColor::ZERO);
        if target_color == self.fill_color {
            return;
        }

        // 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)];

        while let Some((y, mut lx, mut rx)) = stack.pop() {
            // 向左扩展 lx
            while lx - 1 >= 0 && self.pixel_is(lx - 1, y, target_color) {
                lx -= 1;
            }
            // 向右扩展 rx
            while rx + 1 < width && self.pixel_is(rx + 1, y, target_color) {
                rx += 1;
            }

            // 填充当前行 [lx, rx]
            for x in lx..=rx {
                self.fill_pixel_at1(x, y);
            }

            // 检查上一行 (y - 1)
            if y - 1 >= 0 {
                let mut x = lx;
                while x <= rx {
                    if self.pixel_is(x, y - 1, target_color) {
                        let span_start = x;
                        // 跳过连续的目标色块
                        while x <= rx && self.pixel_is(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_is(x, y + 1, target_color) {
                        let span_start = x;
                        while x <= rx && self.pixel_is(x, y + 1, target_color) {
                            x += 1;
                        }
                        stack.push((y + 1, span_start, x - 1));
                    } else {
                        x += 1;
                    }
                }
            }
        }
    }

    /// 圆弧从 x 轴方向开始计算， start_angle end_angle 为弧度，counterclockwise 是否逆时针方向
    pub fn stroke_arc(
        &mut self,
        center: Point,
        radius: f32,
        start_angle: f32,
        end_angle: f32,
        counterclockwise: bool,
    ) {
        if radius <= 1.0 {
            self.fill_pixel_at(center);
            return;
        }

        let start_angle = normalize_radian(start_angle);
        let end_angle = normalize_radian(end_angle);
        let full_circle = (start_angle - end_angle).abs() < f32::EPSILON;

        let min_x = ((center.x - radius) as i32).max(0);
        let max_x = ((center.x + radius) as i32).min(self.width - 1);
        let min_y = ((center.y - radius) as i32).max(0);
        let max_y = ((center.y + radius) as i32).min(self.height - 1);

        let min_r = (radius - self.line_width as f32).max(0.0);
        let max_r = radius + 0.05;

        let min_sq = min_r * min_r;
        let max_sq = max_r * max_r;

        let center_x = center.x as i32;
        let center_y = center.y as i32;
        for y in min_y..=max_y {
            for x in min_x..=max_x {
                let dx = (x - center_x) as f32;
                let dy = (y - center_y) as f32;
                let dist_sq = dx * dx + dy * dy;

                // 判断点是不是在扇区内
                if dist_sq > max_sq || dist_sq <= min_sq {
                    continue;
                }

                // 判断角度是不是在扇区内
                let theta = dy.atan2(dx);
                let theta = normalize_radian(theta);

                if full_circle
                    || (counterclockwise && (theta >= end_angle || theta <= start_angle))
                    || (!counterclockwise && theta >= start_angle && theta <= end_angle)
                {
                    self.stroke_pixel_at1(x, y);
                }
            }
        }
    }

    pub fn clear_rect(&mut self, x: i32, y: i32, width: i32, height: i32) {
        for yi in y..(y + height) {
            self.clear_row(x, x + width, yi);
        }
    }

    fn fill_rect_stroke_color(&mut self, x: i32, y: i32, width: i32, height: i32) {
        let old_fill_color = self.fill_color;
        self.fill_color(self.stroke_color);
        for yi in y..(y + height) {
            self.fill_row(x, x + width, yi);
        }
        self.fill_color(old_fill_color);
    }

    pub fn fill_rect(&mut self, x: i32, y: i32, width: i32, height: i32) {
        for yi in y..(y + height) {
            self.fill_row(x, x + width, yi);
        }
    }

    pub fn fill_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.fill_rect(x as i32, y as i32, width as i32, height as i32);
    }

    /// 填充一个圆角矩形
    /// - x, y: 左上角坐标
    /// - width, height: 尺寸（必须 > 0）
    /// - radius: 圆角半径（会被 clamp 到合理范围）
    pub fn fill_round_rect(&mut self, x: f32, y: f32, width: f32, height: f32, radius: f32) {
        if (width as i32) <= 2 * self.line_width
            || (height as i32) <= 2 * self.line_width
            || width <= 2.0 * radius
            || height <= 2.0 * radius
        {
            self.fill_rect(x as i32, y as i32, width as i32, height as i32);
            return;
        }

        let min_x = x;
        let max_x = x + width - 1.0;
        let min_y = y;
        let max_y = y + height - 1.0;

        // 预计算四个圆角的圆心
        let corners = [
            ((x + radius) as i32, (y + radius) as i32), // 左上
            ((x + width - 1.0 - radius) as i32, (y + radius) as i32), // 右上
            (
                (x + width - 1.0 - radius) as i32,
                (y + height - 1.0 - radius) as i32,
            ), // 右下
            ((x + radius) as i32, (y + height - 1.0 - radius) as i32), // 左下
        ];

        let min_x = min_x as i32;
        let max_x = max_x as i32;
        let min_y = min_y as i32;
        let max_y = max_y as i32;
        let radius_sq = (radius + 0.05) * (radius + 0.05);
        let radius_int = radius as i32;
        for py in min_y..=max_y {
            for px in min_x..=max_x {
                // 判断是否在“直边区域”（无需检查圆角）
                if px >= min_x + radius_int && px <= max_x - radius_int {
                    // 在左右圆角之间的竖直带 → 一定在内部
                    self.fill_pixel_at1(px, py);
                    continue;
                }
                if py >= min_y + radius_int && py <= max_y - radius_int {
                    // 在上下圆角之间的水平带 → 一定在内部
                    self.fill_pixel_at1(px, py);
                    continue;
                }

                // 否则，点位于四个角落之一，需检查是否在四分之一圆内
                let in_corner =
                    // 左上角区域
                    (distance_sq1((px, py), corners[0]) <= radius_sq) ||
                        // 右上角区域
                        (distance_sq1((px, py), corners[1]) <= radius_sq) ||
                        // 右下角区域
                        (distance_sq1((px, py), corners[2]) <= radius_sq) ||
                        // 左下角区域
                        (distance_sq1((px, py), corners[3]) <= radius_sq);

                if in_corner {
                    self.fill_pixel_at1(px, py);
                }
            }
        }
    }

    pub fn fill_round_rect1(&mut self, p1: Point, p2: Point, radius: f32) {
        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.fill_round_rect(x, y, width, height, radius);
    }

    pub fn stroke_round_rect(&mut self, x: f32, y: f32, width: f32, height: f32, radius: f32) {
        if (width as i32) < 2 * self.line_width
            || (height as i32) < 2 * self.line_width
            || width < 2.0 * radius
            || height < 2.0 * radius
        {
            self.fill_rect_stroke_color(x as i32, y as i32, width as i32, height as i32);
            return;
        }

        self.fill_rect_stroke_color(
            (x + radius) as i32,
            y as i32,
            (width - 2.0 * radius) as i32,
            self.line_width,
        );
        self.fill_rect_stroke_color(
            (x + radius) as i32,
            (y + height) as i32 - self.line_width,
            (width - 2.0 * radius) as i32,
            self.line_width,
        );
        self.fill_rect_stroke_color(
            x as i32,
            (y + radius) as i32,
            self.line_width,
            (height - 2.0 * radius) as i32,
        );
        self.fill_rect_stroke_color(
            (x + width) as i32 - self.line_width,
            (y + radius) as i32,
            self.line_width,
            (height - 2.0 * radius) as i32,
        );

        self.stroke_arc(
            Point::new(x + radius, y + radius),
            radius,
            std::f32::consts::PI,
            std::f32::consts::PI + std::f32::consts::FRAC_PI_2,
            false,
        );
        self.stroke_arc(
            Point::new(x + width - 1.0 - radius, y + radius),
            radius,
            0.0,
            std::f32::consts::PI + std::f32::consts::FRAC_PI_2,
            true,
        );
        self.stroke_arc(
            Point::new(x + radius, y + height - 1.0 - radius),
            radius,
            std::f32::consts::FRAC_PI_2,
            std::f32::consts::PI,
            false,
        );
        self.stroke_arc(
            Point::new(x + width - 1.0 - radius, y + height - 1.0 - radius),
            radius,
            0.0,
            std::f32::consts::FRAC_PI_2,
            false,
        );
    }

    pub fn stroke_round_rect1(&mut self, p1: Point, p2: Point, radius: f32) {
        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_round_rect(x, y, width, height, radius);
    }

    pub fn stroke_rect(&mut self, x: i32, y: i32, width: i32, height: i32) {
        if width < 2 * self.line_width || height < 2 * self.line_width {
            self.fill_rect_stroke_color(x, y, width, height);
            return;
        }
        self.fill_rect_stroke_color(x, y, width, self.line_width);
        self.fill_rect_stroke_color(x, y + height - self.line_width, width, self.line_width);
        self.fill_rect_stroke_color(x, y, self.line_width, height);
        self.fill_rect_stroke_color(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 stroke_dashed_rect(
        &mut self,
        x: i32,
        y: i32,
        width: i32,
        height: i32,
        dash_length: i32,
        gap_length: i32,
    ) {
        let mut is_dash = true;

        // 上下两边边框
        for dx in (x..x + width).step_by((dash_length + gap_length) as usize) {
            if is_dash {
                self.stroke_row(dx, dx + dash_length, y);
                self.stroke_row(dx, dx + dash_length, y + height - 1);
            }
            is_dash = !is_dash;
        }

        // 左右两边边框
        for dy in (y..y + height).step_by((dash_length + gap_length) as usize) {
            if is_dash {
                self.stroke_column(dy, dy + dash_length, x);
                self.stroke_column(dy, dy + dash_length, x + width - 1);
            }
            is_dash = !is_dash;
        }
    }

    pub fn stroke_dashed_rect1(&mut self, p1: Point, p2: Point, dash_length: i32, gap_length: i32) {
        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_dashed_rect(
            x as i32,
            y as i32,
            width as i32,
            height as i32,
            dash_length,
            gap_length,
        );
    }

    pub fn clear(&mut self) {
        self.pixels.fill(255);
    }

    pub fn clear_zero(&mut self) {
        self.pixels.fill(0);
    }

    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);
        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
        }
    }

    /// 实现喷枪效果的函数
    pub fn spray_paint(&mut self, center: Point, radius: i32, density: u32) {
        let mut rng = rand::rng();

        for _ in 0..density {
            // 在给定半径内随机产生偏移量
            let offset_x = rng.random_range(-radius..=radius);
            let offset_y = rng.random_range(-radius..=radius);

            // 确保我们只在圆形区域内绘制，而非整个正方形区域
            if (offset_x * offset_x + offset_y * offset_y) <= (radius * radius) {
                let point = Point::new(center.x + offset_x as f32, center.y + offset_y as f32);
                self.fill_pixel_at(point);
            }
        }
    }

    fn recursive_bezier(&mut self, control_points: &[Point], t: f32) -> Point {
        // Implement de Casteljau's algorithm
        let n = control_points.len();
        if n == 1 {
            return control_points[0];
        }
        let mut new_points: Vec<Point> = Vec::with_capacity(n - 1);
        for i in 0..(n - 1) {
            let p0 = control_points[i];
            let p1 = control_points[i + 1];
            let point = point_add(point_muln(p0, 1.0 - t), point_muln(p1, t));
            new_points.push(point);
        }
        self.recursive_bezier(&new_points[..], t)
    }

    pub fn bezier(&mut self, control_points: Vec<Point>) {
        // Iterate through all t = 0 to t = 1 with small steps, and call de Casteljau's recursive Bezier algorithm.
        let mut t = 0.0;
        while t <= 1.0 {
            let point = self.recursive_bezier(&control_points, t);
            self.brush_circle(point);
            t += 0.0005;
        }
    }

    pub fn quadratic_bezier(&mut self, begin: Point, end: Point, p1: Point) {
        let points = vec![begin, p1, end];
        self.bezier(points);
    }

    pub fn cubic_bezier(&mut self, begin: Point, end: Point, p1: Point, p2: Point) {
        let points = vec![begin, p1, p2, end];
        self.bezier(points);
    }

    /// 绘制带线宽的椭圆（描边）
    /// - center: 椭圆中心
    /// - rx, ry: 椭圆的水平/垂直半径（指中心线位置）
    pub fn stroke_ellipse(&mut self, center: Point, rx: f32, ry: f32) {
        if self.line_width <= 0 || rx <= 0.0 || ry <= 0.0 {
            return;
        }

        // 外椭圆半径（膨胀）
        let outer_rx = rx;
        let outer_ry = ry;

        // 内椭圆半径（收缩）——不能为负
        let inner_rx = (rx - self.line_width as f32).max(0.0);
        let inner_ry = (ry - self.line_width as f32).max(0.0);

        // 计算包围矩形（基于外椭圆）
        let min_x = (center.x - outer_rx).ceil() as i32;
        let max_x = (center.x + outer_rx).floor() as i32;
        let min_y = (center.y - outer_ry).ceil() as i32;
        let max_y = (center.y + outer_ry).floor() as i32;

        // 预计算外椭圆参数
        let outer_rx2 = outer_rx * outer_rx;
        let outer_ry2 = outer_ry * outer_ry;
        let outer_threshold = outer_rx2 * outer_ry2;

        // 预计算内椭圆参数（仅当存在内区域时）
        let (inner_rx2, inner_ry2, inner_threshold) = if inner_rx > 0.0 && inner_ry > 0.0 {
            let rx2 = inner_rx * inner_rx;
            let ry2 = inner_ry * inner_ry;
            (rx2, ry2, rx2 * ry2)
        } else {
            (0.0, 0.0, -1.0) // inner_threshold < 0 表示无内区域（实心圆）
        };

        for y in min_y..=max_y {
            for x in min_x..=max_x {
                let dx = x as f32 - center.x;
                let dy = y as f32 - center.y;

                // 判断是否在外椭圆内
                let outer_val = dx * dx * outer_ry2 + dy * dy * outer_rx2;
                if outer_val > outer_threshold {
                    continue; // 在外椭圆外
                }

                // 判断是否在内椭圆内（如果是，则跳过）
                if inner_threshold >= 0.0 {
                    let inner_val = dx * dx * inner_ry2 + dy * dy * inner_rx2;
                    if inner_val <= inner_threshold {
                        continue; // 在内椭圆内 → 不绘制（空心）
                    }
                }

                // 否则：在外椭圆内，且不在内椭圆内 → 属于描边区域
                self.stroke_pixel_at1(x, y);
            }
        }
    }

    pub fn stroke_ellipse1(&mut self, p1: Point, p2: Point) {
        let mut rx = (p2.x - p1.x) / 2.0;
        let mut ry = (p2.y - p1.y) / 2.0;
        if rx > 0.0 && ry > 0.0 {
            let center = Point::new(p1.x + rx, p1.y + ry);
            self.stroke_ellipse(center, rx, ry);
        } else if rx < 0.0 && ry < 0.0 {
            rx = -rx;
            ry = -ry;
            let center = Point::new(p1.x - rx, p1.y - ry);
            self.stroke_ellipse(center, rx, ry);
        } else if ry < 0.0 {
            ry = -ry;
            let center = Point::new(p1.x + rx, p1.y - ry);
            self.stroke_ellipse(center, rx, ry);
        } else {
            rx = -rx;
            let center = Point::new(p1.x - rx, p1.y + ry);
            self.stroke_ellipse(center, rx, ry);
        }
    }

    /// 填充一个椭圆
    /// - center: 椭圆中心
    /// - rx: 水平半径（必须 >= 0）
    /// - ry: 垂直半径（必须 >= 0）
    pub fn fill_ellipse(&mut self, center: Point, rx: f32, ry: f32) {
        if rx <= 0.0 || ry <= 0.0 {
            return;
        }

        let rx = rx;
        let ry = ry;

        // 计算包围矩形（整数边界）
        let min_x = (center.x - rx).ceil() as i32;
        let max_x = (center.x + rx).floor() as i32;
        let min_y = (center.y - ry).ceil() as i32;
        let max_y = (center.y + ry).floor() as i32;

        // 预计算常量：rx², ry², rx² * ry²
        let rx2 = rx * rx;
        let ry2 = ry * ry;
        let rxy2 = rx2 * ry2; // 右边阈值

        for y in min_y..=max_y {
            for x in min_x..=max_x {
                let dx = x as f32 - center.x;
                let dy = y as f32 - center.y;

                // 判断是否在椭圆内：dx²/ rx² + dy²/ ry² <= 1
                // 等价于：dx² * ry² + dy² * rx² <= rx² * ry²
                if dx * dx * ry2 + dy * dy * rx2 <= rxy2 {
                    self.fill_pixel_at1(x, y);
                }
            }
        }
    }

    pub fn fill_ellipse1(&mut self, p1: Point, p2: Point) {
        let mut rx = (p2.x - p1.x) / 2.0;
        let mut ry = (p2.y - p1.y) / 2.0;
        if rx > 0.0 && ry > 0.0 {
            let center = Point::new(p1.x + rx, p1.y + ry);
            self.fill_ellipse(center, rx, ry);
        } else if rx < 0.0 && ry < 0.0 {
            rx = -rx;
            ry = -ry;
            let center = Point::new(p1.x - rx, p1.y - ry);
            self.fill_ellipse(center, rx, ry);
        } else if ry < 0.0 {
            ry = -ry;
            let center = Point::new(p1.x + rx, p1.y - ry);
            self.fill_ellipse(center, rx, ry);
        } else {
            rx = -rx;
            let center = Point::new(p1.x - rx, p1.y + ry);
            self.fill_ellipse(center, rx, ry);
        }
    }

    fn rasterize_polygon(&mut self, points: &[Point]) -> Vec<Point<i32>> {
        let mut result = Vec::new();
        if points.len() < 3 {
            return result;
        }

        // 计算 y 范围
        let min_y = points.iter().map(|p| p.y as i32).min().unwrap_or(0);
        let max_y = points.iter().map(|p| p.y as i32).max().unwrap_or(0);

        // 构建边表（Edge Table）：按 ymin 分组
        let mut edge_table: Vec<Vec<Edge>> = vec![Vec::new(); (max_y - min_y + 1) as usize];

        for i in 0..points.len() {
            let p1 = points[i];
            let p2 = points[(i + 1) % points.len()];
            if let Some(edge) = Edge::new(p1, p2) {
                let idx = (edge.x as i32).min(max_y).max(min_y); // 实际应使用 top.y
                // 正确做法：使用 top.y 作为插入位置
                let top_y = p1.y.min(p2.y) as i32;
                if top_y >= min_y && top_y <= max_y {
                    edge_table[(top_y - min_y) as usize].push(edge);
                }
            }
        }

        // 活动边表（Active Edge List），按 x 排序
        let mut active_edges: Vec<Edge> = Vec::new();

        // 从 min_y 到 max_y 扫描每一行
        for y in min_y..=max_y {
            let y_idx = (y - min_y) as usize;

            // 1. 添加新边（y == ymin 的边）
            if y_idx < edge_table.len() {
                active_edges.append(&mut edge_table[y_idx]);
            }

            // 2. 移除 y >= y_max 的边
            active_edges.retain(|e| y < e.y_max);

            // 3. 按 x 排序
            active_edges.sort_by(|a, b| a.x.partial_cmp(&b.x).unwrap_or(std::cmp::Ordering::Equal));

            // 4. 成对填充像素
            for i in (0..active_edges.len()).step_by(2) {
                if i + 1 < active_edges.len() {
                    let x_start = active_edges[i].x.ceil() as i32;
                    let x_end = active_edges[i + 1].x.floor() as i32;
                    for x in x_start..=x_end {
                        result.push(Point::new(x, y));
                    }
                }
            }

            // 5. 更新活动边的 x（为下一行准备）
            for edge in &mut active_edges {
                edge.x += edge.dx_dy;
            }
        }

        result
    }

    /// 填充一个简单多边形（支持凹多边形）
    pub fn fill_polygon(&mut self, points: &[Point]) {
        let filled_points = self.rasterize_polygon(points);
        self.fill_pixels_i32(filled_points);
    }

    pub fn begin_path(&mut self) {
        self.path2d = Path2D::new();
    }

    pub fn close_path(&mut self) {
        let points = &self.path2d.points;
        if points.len() < 3 {
            return;
        }
        self.path2d.push(points[0]);
    }

    pub fn move_to(&mut self, point: Point) {
        self.path2d.push(point);
    }

    pub fn line_to(&mut self, point: Point) {
        self.path2d.push(point);
    }

    pub fn stroke(&mut self) {
        let mut points = self.path2d.points.clone();
        if points.len() < 2 {
            return;
        }
        // 连线
        for i in 0..(points.len() - 1) {
            self.draw_line_with_circle_brush(points[i], points[i + 1]);
        }
    }

    pub fn fill(&mut self) {
        let points = self.path2d.points.clone();
        self.fill_polygon(&points[..]);
    }

    pub fn draw_rect_selection(&mut self, x: i32, y: i32, rect: &RectSelection) {
        // 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).min(self.width - x).min(rect.w + x);
        let h = (rect.h).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_index = ((dy + src_offset_y) * rect.w as usize + dx + src_offset_x) * 4;
                if rect.pixels[src_index + 3] == 0 {
                    continue;
                }
                let dst_index = ((y + dy) * width + x + dx) * 4;

                self.pixels[dst_index] = rect.pixels[src_index];
                self.pixels[dst_index + 1] = rect.pixels[src_index + 1];
                self.pixels[dst_index + 2] = rect.pixels[src_index + 2];
                self.pixels[dst_index + 3] = rect.pixels[src_index + 3];
            }
        }
    }
}

fn point_muln(point: Point, t: f32) -> Point {
    Point::new(point.x * t, point.y * t)
}

fn point_add(p1: Point, p2: Point) -> Point {
    Point::new(p1.x + p2.x, p1.y + p2.y)
}

/// 将弧度规范到 [0, 2π)
fn normalize_radian(radian: f32) -> f32 {
    let mut r = radian;
    while r < 0.0 {
        r += std::f32::consts::TAU;
    }
    while r >= std::f32::consts::TAU {
        r -= std::f32::consts::TAU;
    }

    r
}

#[inline]
/// 辅助函数：计算两点间距离的平方（避免开方）
fn distance_sq1(a: (i32, i32), b: (i32, i32)) -> f32 {
    let dx = a.0 - b.0;
    let dy = a.1 - b.1;
    (dx * dx + dy * dy) as f32
}