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feat: 实现多边形填充

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yeqing
2026-03-02 14:48:48 +08:00
parent 62be61c574
commit e8d72dd72f
1 changed files with 173 additions and 29 deletions
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202
src/mscanvas.rs
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@@ -1,4 +1,4 @@
use iced::Point;
use iced::{Color, Point};
use rand::prelude::*;
#[derive(Debug, Clone, Copy, PartialEq)]
@@ -35,6 +35,65 @@ impl MSColor {
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,
)
}
}
#[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 {
@@ -61,7 +120,8 @@ pub struct MSCanvas {
pixels_bak: Vec<u8>,
/// 当前笔画颜色
color: MSColor,
foreground_color: MSColor,
background_color: MSColor,
line_width: i32,
@@ -76,14 +136,19 @@ impl MSCanvas {
height,
pixels: vec![255; (width * height * 4) as usize],
pixels_bak: Vec::new(),
color: MSColor::BLACK,
foreground_color: MSColor::BLACK,
background_color: MSColor::WHITE,
line_width: 1,
path2d: Path2D::new(),
}
}
pub fn set_color(&mut self, color: MSColor) {
self.color = color;
pub fn set_foreground_color(&mut self, color: MSColor) {
self.foreground_color = color;
}
pub fn set_background_color(&mut self, color: MSColor) {
self.background_color = color;
}
pub fn set_line_width(&mut self, line_width: i32) {
@@ -168,10 +233,10 @@ impl MSCanvas {
// 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; // R
self.pixels[index + 1] = self.color.g; // G
self.pixels[index + 2] = self.color.b; // B
self.pixels[index + 3] = self.color.a; // A
self.pixels[index] = self.foreground_color.r; // R
self.pixels[index + 1] = self.foreground_color.g; // G
self.pixels[index + 2] = self.foreground_color.b; // B
self.pixels[index + 3] = self.foreground_color.a; // A
}
pub fn draw_pixel_color_at(&mut self, point: Point, color: MSColor) {
@@ -203,13 +268,17 @@ impl MSCanvas {
// 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; // R
self.pixels[index + 1] = self.color.g; // G
self.pixels[index + 2] = self.color.b; // B
self.pixels[index + 3] = self.color.a; // A
self.pixels[index] = self.foreground_color.r; // R
self.pixels[index + 1] = self.foreground_color.g; // G
self.pixels[index + 2] = self.foreground_color.b; // B
self.pixels[index + 3] = self.foreground_color.a; // A
}
pub fn draw_pixel_row(&mut self, xs: i32, xe: i32, y: i32) {
self.draw_pixel_row_color(xs, xe, y, self.foreground_color);
}
pub fn draw_pixel_row_color(&mut self, xs: i32, xe: i32, y: i32, color: MSColor) {
if y < 0 || y >= self.height {
return;
}
@@ -222,10 +291,10 @@ impl MSCanvas {
// 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; // R
self.pixels[index + 1] = self.color.g; // G
self.pixels[index + 2] = self.color.b; // B
self.pixels[index + 3] = self.color.a; // A
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
}
}
@@ -421,7 +490,7 @@ impl MSCanvas {
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 == self.color {
if target_color == self.foreground_color {
return (0, 0);
}
@@ -465,7 +534,7 @@ impl MSCanvas {
}
let target_color = self.pixel_at(start_x, start_y);
if target_color == (self.color) {
if target_color == (self.foreground_color) {
return (0, 0);
}
@@ -609,10 +678,10 @@ impl MSCanvas {
let max_sq = max_r * max_r;
let color = MSColor::new(
(255 + self.color.r) / 2,
self.color.g,
self.color.b,
self.color.a,
(255 + self.foreground_color.r) / 2,
self.foreground_color.g,
self.foreground_color.b,
self.foreground_color.a,
);
let center_x = center.x as i32;
@@ -648,12 +717,20 @@ impl MSCanvas {
}
}
pub fn fill_rect(&mut self, x: i32, y: i32, width: i32, height: i32) {
fn fill_rect_color(&mut self, x: i32, y: i32, width: i32, height: i32, color: MSColor) {
for yi in y..(y + height) {
self.draw_pixel_row(x, x + width, yi);
self.draw_pixel_row_color(x, x + width, yi, color);
}
}
fn fill_rect_foreground_color(&mut self, x: i32, y: i32, width: i32, height: i32) {
self.fill_rect_color(x, y, width, height, self.foreground_color);
}
pub fn fill_rect(&mut self, x: i32, y: i32, width: i32, height: i32) {
self.fill_rect_color(x, y, width, height, self.background_color)
}
pub fn 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
@@ -664,25 +741,25 @@ impl MSCanvas {
return;
}
self.fill_rect(
self.fill_rect_foreground_color(
(x + radius) as i32,
y as i32,
(width - 2.0 * radius) as i32,
self.line_width,
);
self.fill_rect(
self.fill_rect_foreground_color(
(x + radius) as i32,
(y + height) as i32 - self.line_width,
(width - 2.0 * radius) as i32,
self.line_width,
);
self.fill_rect(
self.fill_rect_foreground_color(
x as i32,
(y + radius) as i32,
self.line_width,
(height - 2.0 * radius) as i32,
);
self.fill_rect(
self.fill_rect_foreground_color(
(x + width) as i32 - self.line_width,
(y + radius) as i32,
self.line_width,
@@ -913,6 +990,68 @@ impl MSCanvas {
}
}
/// 填充一个简单多边形（支持凹多边形）
pub fn fill_polygon(&mut self, points: &[Point]) {
if points.len() < 3 {
return;
}
// 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 {
self.draw_pixel_color_at(Point::new(x as f32, y as f32), self.background_color);
}
}
}
// 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;
}
}
}
pub fn begin_path(&mut self) {
self.path2d = Path2D::new();
}
@@ -943,6 +1082,11 @@ impl MSCanvas {
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[..]);
}
}
fn point_muln(point: Point, t: f32) -> Point {