1 files changed, 71 insertions, 0 deletions
diff --git a/vendor/plotters/examples/mandelbrot.rs b/vendor/plotters/examples/mandelbrot.rs
new file mode 100644
index 000000000..413c319c6
--- /dev/null
+++ b/vendor/plotters/examples/mandelbrot.rs
@@ -0,0 +1,71 @@
+use plotters::prelude::*;
+use std::ops::Range;
+
+const OUT_FILE_NAME: &'static str = "plotters-doc-data/mandelbrot.png";
+fn main() -> Result<(), Box<dyn std::error::Error>> {
+    let root = BitMapBackend::new(OUT_FILE_NAME, (800, 600)).into_drawing_area();
+
+    root.fill(&WHITE)?;
+
+    let mut chart = ChartBuilder::on(&root)
+        .margin(20)
+        .x_label_area_size(10)
+        .y_label_area_size(10)
+        .build_cartesian_2d(-2.1f64..0.6f64, -1.2f64..1.2f64)?;
+
+    chart
+        .configure_mesh()
+        .disable_x_mesh()
+        .disable_y_mesh()
+        .draw()?;
+
+    let plotting_area = chart.plotting_area();
+
+    let range = plotting_area.get_pixel_range();
+
+    let (pw, ph) = (range.0.end - range.0.start, range.1.end - range.1.start);
+    let (xr, yr) = (chart.x_range(), chart.y_range());
+
+    for (x, y, c) in mandelbrot_set(xr, yr, (pw as usize, ph as usize), 100) {
+        if c != 100 {
+            plotting_area.draw_pixel((x, y), &HSLColor(c as f64 / 100.0, 1.0, 0.5))?;
+        } else {
+            plotting_area.draw_pixel((x, y), &BLACK)?;
+        }
+    }
+
+    // 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(())
+}
+
+fn mandelbrot_set(
+    real: Range<f64>,
+    complex: Range<f64>,
+    samples: (usize, usize),
+    max_iter: usize,
+) -> impl Iterator<Item = (f64, f64, usize)> {
+    let step = (
+        (real.end - real.start) / samples.0 as f64,
+        (complex.end - complex.start) / samples.1 as f64,
+    );
+    return (0..(samples.0 * samples.1)).map(move |k| {
+        let c = (
+            real.start + step.0 * (k % samples.0) as f64,
+            complex.start + step.1 * (k / samples.0) as f64,
+        );
+        let mut z = (0.0, 0.0);
+        let mut cnt = 0;
+        while cnt < max_iter && z.0 * z.0 + z.1 * z.1 <= 1e10 {
+            z = (z.0 * z.0 - z.1 * z.1 + c.0, 2.0 * z.0 * z.1 + c.1);
+            cnt += 1;
+        }
+        return (c.0, c.1, cnt);
+    });
+}
+#[test]
+fn entry_point() {
+    main().unwrap()
+}