Draw rounded rects and quarter circles

src/draw.rs

@@ -1,6 +1,13 @@
 use crate::abi::UiPanel;
 use crate::{Color, Vec2};
 
+pub enum Corner {
+    TopRight,
+    BottomRight,
+    BottomLeft,
+    TopLeft,
+}
+
 pub struct DrawContext {
     panel: UiPanel,
     offset: Vec2,
@@ -44,6 +51,28 @@ impl DrawContext {
         }
     }
 
+    pub fn draw_quarter_circle(&self, corner: Corner, center: Vec2, radius: f32, color: Color) {
+        use std::f32::consts::{FRAC_PI_2, PI};
+
+        let spoke_num = 16.0;
+        let delta = PI / 4.0 / spoke_num;
+
+        let (mut theta, limit) = match corner {
+            Corner::TopRight => (0.0, FRAC_PI_2),
+            Corner::BottomRight => (FRAC_PI_2 * 3.0, PI * 2.0),
+            Corner::BottomLeft => (PI, FRAC_PI_2 * 3.0),
+            Corner::TopLeft => (FRAC_PI_2, PI),
+        };
+
+        let mut last_spoke = Vec2::from_angle(theta) * radius + center;
+        while theta < limit {
+            theta += delta;
+            let new_spoke = Vec2::from_angle(theta) * radius + center;
+            self.draw_triangle(center, last_spoke, new_spoke, color);
+            last_spoke = new_spoke;
+        }
+    }
+
     pub fn draw_ring(&self, center: Vec2, radius: f32, thickness: f32, color: Color) {
         use std::f32::consts::PI;
 
@@ -68,16 +97,43 @@ impl DrawContext {
         }
     }
 
-    pub fn draw_rect(&self, xy: &Vec2, size: &Vec2, color: Color) {
-        let v1 = *xy;
+    pub fn draw_rect(&self, xy: Vec2, size: Vec2, color: Color) {
+        let v1 = xy;
         let v2 = v1 + Vec2::new(size.x, 0.0);
         let v3 = v1 + Vec2::new(0.0, size.y);
-        let v4 = v1 + *size;
+        let v4 = v1 + size;
 
         self.draw_triangle(v1, v2, v3, color);
         self.draw_triangle(v2, v3, v4, color);
     }
 
+    pub fn draw_rounded_rect(&self, xy: Vec2, size: Vec2, radius: f32, color: Color) {
+        let xoff = Vec2::new(radius, 0.0);
+        let yoff = Vec2::new(0.0, radius);
+        let sizex = Vec2::new(size.x, 0.0);
+        let sizey = Vec2::new(0.0, size.y);
+        let inner_size = size - Vec2::new(radius, radius) * 2.0;
+        let lr_edge_size = Vec2::new(radius, inner_size.y);
+        let tb_edge_size = Vec2::new(inner_size.x, radius);
+
+        self.draw_rect(xy + yoff, lr_edge_size, color); // left edge
+        self.draw_rect(xy + yoff + sizex - xoff, lr_edge_size, color); // right edge
+        self.draw_rect(xy + xoff, tb_edge_size, color); // bottom edge
+        self.draw_rect(xy + xoff + sizey - yoff, tb_edge_size, color); // top edge
+
+        let tr = xy + size - xoff - yoff;
+        let br = xy + sizex - xoff + yoff;
+        let bl = xy + xoff + yoff;
+        let tl = xy + sizey + xoff - yoff;
+
+        self.draw_quarter_circle(Corner::TopRight, tr, radius, color);
+        self.draw_quarter_circle(Corner::BottomRight, br, radius, color);
+        self.draw_quarter_circle(Corner::BottomLeft, bl, radius, color);
+        self.draw_quarter_circle(Corner::TopLeft, tl, radius, color);
+
+        self.draw_rect(bl, inner_size, color);
+    }
+
     pub fn with_offset(&self, offset: Vec2) -> Self {
         Self {
             offset: self.offset + offset,