new example for drawing arcs and circle sections

Cargo.toml

@@ -98,6 +98,10 @@ required-features = ["draw"]
 name = "draw_animation_list"
 required-features = ["draw"]
 
+[[example]]
+name = "draw_arcs"
+required-features = ["draw"]
+
 [[example]]
 name = "draw_atlas"
 required-features = ["draw"]

examples/draw_arcs.rs

@@ -0,0 +1,79 @@
+use notan::draw::*;
+use notan::prelude::*;
+
+#[notan_main]
+fn main() -> Result<(), String> {
+    notan::init().add_config(DrawConfig).draw(draw).build()
+}
+
+fn draw(gfx: &mut Graphics) {
+    let mut draw = gfx.create_draw();
+    draw.clear(Color::BLACK);
+
+    let center_x: f32 = 400.0;  // x-coordinate of center of arc
+    let center_y: f32 = 300.0;  // y-coordinate of center of arc
+    let radius: f32 = 150.0;  // radius of arc
+
+    let mut draw = gfx.create_draw();
+    draw.clear(Color::BLACK);
+    {
+        let mut path = draw.path();
+        path.move_to(center_x, center_y);
+        draw_arc(&mut path, center_x, center_y, radius, 120.0, 240.0);
+        path.color(Color::GREEN).stroke(4.0);
+    }
+    {
+        let mut path = draw.path();
+        path.move_to(center_x, center_y);
+        draw_circle_section(&mut path, center_x, center_y, radius, 240.0, 360.0);
+        path.color(Color::BLUE)
+            .stroke(4.0)
+            .fill();
+    }
+    {
+        let mut path = draw.path();
+        path.move_to(center_x, center_y);
+        draw_arc(&mut path, center_x, center_y, radius, 0.0, 120.0);
+        path.color(Color::RED).stroke(4.0);
+    }
+    gfx.render(&draw);
+}
+
+
+fn draw_arc(path: &mut Path, center_x: f32, center_y: f32, radius: f32, start_angle: f32, end_angle: f32) -> &mut Path {
+    let start_angle = start_angle + 270.0;
+    let end_angle = end_angle + 270.0;
+
+    let (start_x, start_y) = get_coords(center_x, center_y, radius, start_angle);
+    path.move_to(start_x, start_y);
+    for degrees in ((start_angle as u32)..(end_angle as u32)).step_by(5) {
+        let (x1, y1) = get_coords(center_x, center_y, radius, degrees as f32);
+        path.line_to(x1, y1);
+    }
+    let (end_x, end_y) = get_coords(center_x, center_y, radius, end_angle as f32);
+    path.line_to(end_x, end_y);
+    path
+}
+
+fn draw_circle_section(path: &mut Path, center_x: f32, center_y: f32, radius: f32, start_angle: f32, end_angle: f32) -> &mut Path {
+    let start_angle = start_angle + 270.0;
+    let end_angle = end_angle + 270.0;
+
+    let (start_x, start_y) = get_coords(center_x, center_y, radius, start_angle);
+    path.line_to(start_x, start_y);
+    for degrees in ((start_angle as u32)..(end_angle as u32)).step_by(5) {
+        let (x1, y1) = get_coords(center_x, center_y, radius, degrees as f32);
+        path.line_to(x1, y1);
+    }
+    let (end_x, end_y) = get_coords(center_x, center_y, radius, end_angle as f32);
+    path.line_to(end_x, end_y);
+    path.line_to(center_x, center_y);
+    path
+}
+
+
+fn get_coords(center_x: f32, center_y: f32, radius: f32, degrees: f32) -> (f32, f32) {
+    let x = center_x + radius * (degrees as f32 * std::f32::consts::PI / 180.0).cos();
+    let y = center_y + radius * (degrees as f32 * std::f32::consts::PI / 180.0).sin();
+    (x, y)
+}