Data commit

Task/Sierpinski-triangle-Graphical/Rust/sierpinski-triangle-graphical.rust

@@ -0,0 +1,64 @@
+// [dependencies]
+// svg = "0.8.0"
+
+const SQRT3_2: f64 = 0.86602540378444;
+
+fn sierpinski_triangle(
+    mut document: svg::Document,
+    mut x: f64,
+    mut y: f64,
+    mut side: f64,
+    order: usize,
+) -> svg::Document {
+    use svg::node::element::Polygon;
+
+    if order == 1 {
+        let mut points = Vec::new();
+        points.push((x, y));
+        y += side * SQRT3_2;
+        x -= side * 0.5;
+        points.push((x, y));
+        x += side;
+        points.push((x, y));
+        let polygon = Polygon::new()
+            .set("fill", "black")
+            .set("stroke", "none")
+            .set("points", points);
+        document = document.add(polygon);
+    } else {
+        side *= 0.5;
+        document = sierpinski_triangle(document, x, y, side, order - 1);
+        y += side * SQRT3_2;
+        x -= side * 0.5;
+        document = sierpinski_triangle(document, x, y, side, order - 1);
+        x += side;
+        document = sierpinski_triangle(document, x, y, side, order - 1);
+    }
+    document
+}
+
+fn write_sierpinski_triangle(file: &str, size: usize, order: usize) -> std::io::Result<()> {
+    use svg::node::element::Rectangle;
+
+    let margin = 20.0;
+    let side = (size as f64) - 2.0 * margin;
+    let y = 0.5 * ((size as f64) - SQRT3_2 * side);
+    let x = margin + side * 0.5;
+
+    let rect = Rectangle::new()
+        .set("width", "100%")
+        .set("height", "100%")
+        .set("fill", "white");
+
+    let mut document = svg::Document::new()
+        .set("width", size)
+        .set("height", size)
+        .add(rect);
+
+    document = sierpinski_triangle(document, x, y, side, order);
+    svg::save(file, &document)
+}
+
+fn main() {
+    write_sierpinski_triangle("sierpinski_triangle.svg", 600, 8).unwrap();
+}