saturation 0.2.3

use plotters::prelude::*;

type T = f32;

const PLOT_RES: (u32, u32) = (1024, 760);
const PLOT_CAPTION_FONT: (&str, u32) = ("sans", 20);
const PLOT_MARGIN: u32 = 5;
const PLOT_LABEL_AREA_SIZE: u32 = 30;

pub fn plot_curves<const N: usize, const M: usize>(
    plot_title: &str, plot_path: &str,
    x: [[T; N]; M],
    y: [[T; N]; M]
) -> Result<(), Box<dyn std::error::Error>>
{
    let x_min = x.into_iter().flatten().reduce(T::min).unwrap();
    let x_max = x.into_iter().flatten().reduce(T::max).unwrap();
    
    let y_min = y.into_iter().flatten().reduce(T::min).unwrap();
    let y_max = y.into_iter().flatten().reduce(T::max).unwrap();
    
    let area = BitMapBackend::new(plot_path, PLOT_RES).into_drawing_area();
    
    area.fill(&WHITE)?;
    
    let mut chart = ChartBuilder::on(&area)
        .caption(plot_title, PLOT_CAPTION_FONT.into_font())
        .margin(PLOT_MARGIN)
        .x_label_area_size(PLOT_LABEL_AREA_SIZE)
        .y_label_area_size(PLOT_LABEL_AREA_SIZE)
        .build_cartesian_2d(x_min..x_max, y_min..y_max)?;
    
    chart.configure_mesh()
        .set_all_tick_mark_size(0.1)
        .draw()?;
    
    for (i, (x, y)) in x.into_iter().zip(y).enumerate()
    {
        let mut j = i;
        if j == 2
        {
            j += 1
        }
        let color = Palette99::pick(j);
        chart.draw_series(LineSeries::new(
                x.into_iter().zip(y),
                &color
            ))?
        .label(format!("{}", i))
        .legend(move |(x, y)| Rectangle::new([(x + 5, y - 5), (x + 15, y + 5)], color.mix(0.5).filled()));
    }
    
    chart.configure_series_labels()
        .border_style(&BLACK)
        .draw()?;
        
    // To avoid the IO failure being ignored silently, we manually call the present function
    area.present().expect("Unable to write result to file");

    Ok(())
}