create iterator structure

src/circle.rs

@@ -0,0 +1,18 @@
+use crate::shapes::Shape;
+
+/// An iterator containing the shapes to display
+pub struct CircleShapes;
+
+impl CircleShapes {
+    pub fn new() -> CircleShapes {
+        CircleShapes {}
+    }
+}
+
+impl Iterator for CircleShapes {
+    type Item = Shape;
+
+    fn next(&mut self) -> Option<Self::Item> {
+        None
+    }
+}

src/drawing.rs

@@ -13,3 +13,11 @@ pub fn draw_line(line: Line, context: &web_sys::CanvasRenderingContext2d) {
     context
         .line_to(line.p2.x, line.p2.y);
 }
+
+pub fn draw_shape(shape: Shape, context: &web_sys::CanvasRenderingContext2d) {
+    match shape {
+        Shape::Circle(circle) => draw_circle(circle, context),
+        Shape::Line(line) => draw_line(line, context),
+        Shape::Point(_) => (),
+    }
+}

src/lib.rs

@@ -3,8 +3,10 @@ use wasm_bindgen::JsCast;
 
 mod drawing;
 mod shapes;
+mod circle;
 
 use shapes::*;
+use circle::CircleShapes;
 
 #[wasm_bindgen(start)]
 pub fn start() {
@@ -24,6 +26,11 @@ pub fn start() {
 
     context.begin_path();
   
+    let iter = CircleShapes::new();
+    for shape in iter {
+        drawing::draw_shape(shape, &context);
+    }
+  
     drawing::draw_circle(Circle {center: Point {x: 75.0, y: 75.0}, radius: 70.0}, &context);
     drawing::draw_circle(Circle {center: Point {x: 75.0, y: 75.0}, radius: 35.0}, &context);
     drawing::draw_circle(Circle {center: Point {x: 60.0, y: 65.0}, radius: 5.0}, &context);

src/shapes.rs

@@ -12,3 +12,9 @@ pub struct Line {
   pub p1: Point,
   pub p2: Point,
 }
+
+pub enum Shape {
+    Point(Point),
+    Circle(Circle),
+    Line(Line),
+}