yeqing/mspaint
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

feat: 椭圆支持线宽和一些重构

Browse Source
This commit is contained in:
yeqing
2026-03-03 21:06:41 +08:00
parent 849cfb247d
commit 09d29473bb
2 changed files with 91 additions and 96 deletions
Download Patch File Download Diff File Expand all files Collapse all files

122
src/mscanvas.rs
View File

@@ -87,8 +87,8 @@ impl Edge {
return None;
}
let dx = (bottom.x - top.x);
let dy = (bottom.y - top.y);
let dx = bottom.x - top.x;
let dy = bottom.y - top.y;
let dx_dy = dx / dy;
Some(Edge {
@@ -208,7 +208,7 @@ impl MSCanvas {
pub fn pixel_at(&self, x: i32, y: i32) -> MSColor {
// 边界检查
if x < 0 || x >= self.width || y < 0 || y >= self.height as i32 {
if x < 0 || x >= self.width || y < 0 || y >= self.height {
return MSColor::ZERO;
}
@@ -273,7 +273,7 @@ impl MSCanvas {
}
let xs = xs.clamp(0, self.width - 1);
let xe = xe.clamp(0, self.width as i32);
let xe = xe.clamp(0, self.width);
for x in xs..xe {
let index = ((y * self.width + x) * 4) as usize;
@@ -885,7 +885,7 @@ impl MSCanvas {
}
let xs = xs.clamp(0, self.width - 1);
let xe = xe.clamp(0, self.width as i32);
let xe = xe.clamp(0, self.width);
for x in xs..xe {
let index = ((y * self.width + x) * 4) as usize;
@@ -951,47 +951,63 @@ impl MSCanvas {
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) {
let mut x = 0.0;
let mut y = ry; // 初始时将y设置为半高
// 计算初始决策参数
let mut decision = ry * ry - rx * rx * ry + rx * rx / 4.0;
while ry * ry * x < rx * rx * y {
// 在每个阶段，根据对称性绘制四个方向上的点
self.stroke_pixel_at(Point::new(center.x + x, center.y + y));
self.stroke_pixel_at(Point::new(center.x - x, center.y + y));
self.stroke_pixel_at(Point::new(center.x + x, center.y - y));
self.stroke_pixel_at(Point::new(center.x - x, center.y - y));
if decision < 0.0 {
x += 1.0;
decision += 2.0 * ry * ry * x + ry * ry;
} else {
x += 1.0;
y -= 1.0;
decision += 2.0 * ry * ry * x - 2.0 * rx * rx * y + ry * ry;
}
if self.line_width <= 0 || rx <= 0.0 || ry <= 0.0 {
return;
}
decision =
ry * ry * (x + 0.5) * (x + 0.5) + rx * rx * (y - 1.0) * (y - 1.0) - rx * rx * ry * ry;
// 外椭圆半径（膨胀）
let outer_rx = rx;
let outer_ry = ry;
while y > 0.0 {
// 同样地，根据对称性绘制四个方向上的点
self.stroke_pixel_at(Point::new(center.x + x, center.y + y));
self.stroke_pixel_at(Point::new(center.x - x, center.y + y));
self.stroke_pixel_at(Point::new(center.x + x, center.y - y));
self.stroke_pixel_at(Point::new(center.x - x, center.y - y));
// 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);
if decision > 0.0 {
y -= 1.0;
decision += rx * rx - 2.0 * rx * rx * y;
} else {
x += 1.0;
y -= 1.0;
decision += 2.0 * ry * ry * x - 2.0 * rx * rx * y + rx * rx;
// 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);
}
}
}
@@ -1027,14 +1043,14 @@ impl MSCanvas {
return;
}
let rx = rx as f32;
let ry = ry as f32;
let rx = rx;
let ry = ry;
// 计算包围矩形（整数边界）
let min_x = (center.x as f32 - rx).ceil() as i32;
let max_x = (center.x as f32 + rx).floor() as i32;
let min_y = (center.y as f32 - ry).ceil() as i32;
let max_y = (center.y as f32 + ry).floor() as i32;
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;
@@ -1043,8 +1059,8 @@ impl MSCanvas {
for y in min_y..=max_y {
for x in min_x..=max_x {
let dx = x as f32 - center.x as f32;
let dy = y as f32 - center.y as f32;
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
@@ -1197,14 +1213,6 @@ fn normalize_radian(radian: f32) -> f32 {
r
}
#[inline]
/// 辅助函数：计算两点间距离的平方（避免开方）
fn distance_sq(a: Point, b: Point) -> f32 {
let dx = a.x - b.x;
let dy = a.y - b.y;
dx * dx + dy * dy
}
#[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 {