1 files changed, 57 insertions, 0 deletions
diff --git a/vendor/plotters/examples/snowflake.rs b/vendor/plotters/examples/snowflake.rs
new file mode 100644
index 000000000..6e52f25b6
--- /dev/null
+++ b/vendor/plotters/examples/snowflake.rs
@@ -0,0 +1,57 @@
+use plotters::prelude::*;
+
+fn snowflake_iter(points: &[(f64, f64)]) -> Vec<(f64, f64)> {
+    let mut ret = vec![];
+    for i in 0..points.len() {
+        let (start, end) = (points[i], points[(i + 1) % points.len()]);
+        let t = ((end.0 - start.0) / 3.0, (end.1 - start.1) / 3.0);
+        let s = (
+            t.0 * 0.5 - t.1 * (0.75f64).sqrt(),
+            t.1 * 0.5 + (0.75f64).sqrt() * t.0,
+        );
+        ret.push(start);
+        ret.push((start.0 + t.0, start.1 + t.1));
+        ret.push((start.0 + t.0 + s.0, start.1 + t.1 + s.1));
+        ret.push((start.0 + t.0 * 2.0, start.1 + t.1 * 2.0));
+    }
+    ret
+}
+
+const OUT_FILE_NAME: &'static str = "plotters-doc-data/snowflake.png";
+fn main() -> Result<(), Box<dyn std::error::Error>> {
+    let root = BitMapBackend::new(OUT_FILE_NAME, (1024, 768)).into_drawing_area();
+
+    root.fill(&WHITE)?;
+
+    let mut chart = ChartBuilder::on(&root)
+        .caption("Koch's Snowflake", ("sans-serif", 50))
+        .build_cartesian_2d(-2.0..2.0, -1.5..1.5)?;
+
+    let mut snowflake_vertices = {
+        let mut current: Vec<(f64, f64)> = vec![
+            (0.0, 1.0),
+            ((3.0f64).sqrt() / 2.0, -0.5),
+            (-(3.0f64).sqrt() / 2.0, -0.5),
+        ];
+        for _ in 0..6 {
+            current = snowflake_iter(&current[..]);
+        }
+        current
+    };
+
+    chart.draw_series(std::iter::once(Polygon::new(
+        snowflake_vertices.clone(),
+        &RED.mix(0.2),
+    )))?;
+    snowflake_vertices.push(snowflake_vertices[0]);
+    chart.draw_series(std::iter::once(PathElement::new(snowflake_vertices, &RED)))?;
+
+    // To avoid the IO failure being ignored silently, we manually call the present function
+    root.present().expect("Unable to write result to file, please make sure 'plotters-doc-data' dir exists under current dir");
+    println!("Result has been saved to {}", OUT_FILE_NAME);
+    Ok(())
+}
+#[test]
+fn entry_point() {
+    main().unwrap()
+}