terminal-vibes 1.6.6

Terminal-based music visualizer for system audio
Documentation 
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use crate::processing::FrameData;
use crate::visualizations::render::quantize_color;
use crate::visualizations::Visualization;
use ratatui::buffer::Buffer;
use ratatui::layout::Rect;
use ratatui::style::Color;
use std::collections::VecDeque;

pub struct Spectrogram {
    history: VecDeque<Vec<f32>>,
    /// Track which frames had a beat for marker rendering
    beat_markers: VecDeque<bool>,
    max_history: usize,
    quant_step: u8,
}

impl Spectrogram {
    pub fn new(max_history: usize) -> Self {
        Self {
            history: VecDeque::with_capacity(max_history),
            beat_markers: VecDeque::with_capacity(max_history),
            max_history,
            quant_step: 16,
        }
    }
}

impl Visualization for Spectrogram {
    fn name(&self) -> &str {
        "spectrogram"
    }

    fn update(&mut self, frame: &FrameData) {
        // Recycle a buffer from the front if at capacity, avoiding allocation
        let mut recycled = if self.history.len() >= self.max_history {
            self.beat_markers.pop_front();
            self.history.pop_front().unwrap()
        } else {
            Vec::new()
        };
        recycled.resize(frame.spectrum.len(), 0.0);
        recycled.copy_from_slice(&frame.spectrum);
        self.history.push_back(recycled);
        self.beat_markers.push_back(frame.beat.beat);
    }

    fn render(&mut self, area: Rect, buf: &mut Buffer) {
        if area.width == 0 || area.height == 0 || self.history.is_empty() {
            return;
        }

        let cols = area.width as usize;
        let rows = area.height as usize;
        let total = self.history.len();
        let visible_count = cols.min(total);
        let skip = total - visible_count;

        let x_offset = cols.saturating_sub(visible_count);

        // Iterate directly over the tail of history — zero intermediate allocations
        for (col_idx, (spectrum, &is_beat)) in self
            .history
            .iter()
            .zip(self.beat_markers.iter())
            .skip(skip)
            .enumerate()
        {
            let x = area.x + (x_offset + col_idx) as u16;
            if x >= area.x + area.width {
                continue;
            }

            for row in 0..rows {
                // Map row to frequency band (bottom = low freq, top = high freq)
                let band_idx = ((rows - 1 - row) * spectrum.len()) / rows.max(1);
                let band_idx = band_idx.min(spectrum.len().saturating_sub(1));
                let intensity = if spectrum.is_empty() {
                    0.0
                } else {
                    spectrum[band_idx].clamp(0.0, 1.0)
                };

                let y = area.y + row as u16;
                // Beat frames get a strong brightness boost — visible column markers
                let display_intensity = if is_beat {
                    (intensity + 0.5).clamp(0.0, 1.0)
                } else {
                    intensity
                };
                let color = quantize_color(magma_colormap(display_intensity), self.quant_step);

                buf[(x, y)]
                    .set_char(intensity_char(display_intensity))
                    .set_fg(color);
            }
        }
    }

    fn set_quantization_step(&mut self, step: u8) {
        self.quant_step = step;
    }

    fn apply_config(&mut self, config: &toml::Value) {
        if let Some(len) = config.get("history_length").and_then(|v| v.as_integer()) {
            self.max_history = len as usize;
        }
    }

    fn save_config(&self) -> toml::Value {
        let mut table = toml::value::Table::new();
        table.insert(
            "history_length".to_string(),
            toml::Value::Integer(self.max_history as i64),
        );
        toml::Value::Table(table)
    }
}

/// Map intensity (0.0..1.0) to a block character of varying density.
fn intensity_char(intensity: f32) -> char {
    match (intensity * 4.0) as u8 {
        0 => ' ',
        1 => '\u{2591}', // light shade
        2 => '\u{2592}', // medium shade
        3 => '\u{2593}', // dark shade
        _ => '\u{2588}', // full block
    }
}

/// Simple magma-ish colormap: black -> purple -> orange -> yellow.
fn magma_colormap(t: f32) -> Color {
    let t = t.clamp(0.0, 1.0);
    let (r, g, b) = if t < 0.33 {
        let s = t / 0.33;
        ((s * 120.0) as u8, 0u8, (s * 150.0) as u8)
    } else if t < 0.66 {
        let s = (t - 0.33) / 0.33;
        (
            120 + (s * 135.0) as u8,
            (s * 80.0) as u8,
            150 - (s * 150.0) as u8,
        )
    } else {
        let s = (t - 0.66) / 0.34;
        (255, 80 + (s * 175.0) as u8, (s * 80.0) as u8)
    };
    Color::Rgb(r, g, b)
}