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use plotters::prelude::*;
use std::ops::Range;
fn main() -> Result<(), Box<dyn std::error::Error>> {
let root =
BitMapBackend::new("plotters-doc-data/mandelbrot.png", (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)?;
}
}
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()
}
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