tek/src/sampler/sample_viewer.rs

use crate::*;
use std::ops::Deref;
use ratatui::{prelude::Rect, widgets::{Widget, canvas::{Canvas, Points, Line}}};

const EMPTY: &[(f64, f64)] = &[(0., 0.), (1., 1.), (2., 2.), (0., 2.), (2., 0.)];

pub struct SampleViewer(pub Option<Arc<RwLock<Sample>>>);
render!(<Tui>|self: SampleViewer|render(|to|{
    let [x, y, width, height] = to.area();
    let area = Rect { x, y, width, height };
    let min_db = -40.0;
    let (x_bounds, y_bounds, lines): ([f64;2], [f64;2], Vec<Line>) =
        if let Some(sample) = &self.0 {
            let sample = sample.read().unwrap();
            let start  = sample.start  as f64;
            let end    = sample.end    as f64;
            let length = end - start;
            let step   = length / width as f64;
            let mut t = start;
            let mut lines = vec![];
            while t < end {
                let chunk = &sample.channels[0][t as usize..((t + step) as usize).min(sample.end)];
                let total: f32 = chunk.iter().map(|x|x.abs()).sum();
                let count = chunk.len() as f32;
                let meter = 10. * (total / count).log10();
                let x = t as f64;
                let y = meter as f64;
                lines.push(Line::new(x, min_db, x, y, Color::Green));
                t += step / 2.;
            }
            (
                [sample.start as f64, sample.end as f64],
                [min_db, 0.],
                lines
            )
        } else {
            (
                [0.0, width  as f64],
                [0.0, height as f64],
                vec![
                    Line::new(0.0, 0.0, width as f64, height as f64, Color::Red),
                    Line::new(width as f64, 0.0, 0.0, height as f64, Color::Red),
                ]
            )
        };
    Canvas::default().x_bounds(x_bounds).y_bounds(y_bounds).paint(|ctx|{
        for line in lines.iter() {
            ctx.draw(line)
        }
    }).render(area, &mut to.buffer);
    Ok(())
}));