audio-visualizer 0.3.1

/*
MIT License

Copyright (c) 2021 Philipp Schuster

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.
*/
//! Helps to visualize audio data

use crate::dynamic::window_top_btm::pixel_buf::PixelBuf;
use minifb::{Window, WindowOptions};
use plotters::chart::{ChartBuilder, ChartState};
use plotters::coord::cartesian::Cartesian2d;
use plotters::coord::types::RangedCoordf64;
use plotters::coord::Shift;
use plotters::drawing::{DrawingArea, IntoDrawingArea};
use plotters::style::{IntoFont, WHITE};
use plotters_bitmap::bitmap_pixel::BGRXPixel;
use plotters_bitmap::BitMapBackend;
use std::borrow::{Borrow, BorrowMut};
use std::ops::Range;

/// Width of the window.
pub const DEFAULT_W: usize = 1280;
/// Height of the window.
pub const DEFAULT_H: usize = 720;

/// Initializes the [`minifb`] window and draws the initial grid into it.
/// It splits the drawing area into an upper chart and a lower chart. The
/// upper exists to show original audio data. The lower exists to show transformed
/// audio data, e.g. spectrum or lowpass filter.
///
/// # Parameters
/// - `name` Name of the GUI window
/// - `preferred_height` Preferred height of GUI window. Default is [`DEFAULT_H`].
/// - `preferred_width` Preferred height of GUI window. Default is [`DEFAULT_W`].
/// - `preferred_x_range` Preferred range for the x-axis of the lower (=custom) diagram.
///                       If no value is present, the same value as for the upper diagram is used.
/// - `preferred_y_range` Preferred range for the y-axis of the lower (=custom) diagram.
///                       If no value is present, the same value as for the upper diagram is used.
/// - `x_desc` Description for the x-axis of the lower (=custom) diagram.
/// - `y_desc` Description for the y-axis of the lower (=custom) diagram.
/// - `audio_buffer_len` Number of elements in the audio buffer. Needed for the scaling of the x-axis.
/// - `time_per_sample` Time per sample. Needed for the scaling of the x-axis.
///
/// # Returns
/// - window object
/// - chartstate of the upper chart
/// - chartstate of the lower chart
/// - the shared pixel buf
#[allow(clippy::type_complexity, clippy::too_many_arguments)]
pub fn setup_window(
    name: &str,
    preferred_height: Option<usize>,
    preferred_width: Option<usize>,
    preferred_x_range: Option<Range<f64>>,
    preferred_y_range: Option<Range<f64>>,
    x_desc: &str,
    y_desc: &str,
    audio_buffer_len: usize,
    time_per_sample: f64,
) -> (
    Window,
    ChartState<Cartesian2d<RangedCoordf64, RangedCoordf64>>,
    ChartState<Cartesian2d<RangedCoordf64, RangedCoordf64>>,
    PixelBuf,
) {
    let height = preferred_height.unwrap_or(DEFAULT_H);
    let width = preferred_width.unwrap_or(DEFAULT_W);
    let mut window =
        Window::new(&String::from(name), width, height, WindowOptions::default()).unwrap();
    let x_range_top = -(audio_buffer_len as f64 * time_per_sample)..0.0;
    let y_range_top = -1.0..1.01;
    let x_range_btm = preferred_x_range.unwrap_or_else(|| x_range_top.clone());
    let y_range_btm = preferred_y_range.unwrap_or_else(|| y_range_top.clone());

    // Buffer where we draw the Chart as bitmap into: we update the "minifb" window from it too
    let mut pixel_buf = PixelBuf(vec![0_u32; width * height]);

    let (top_drawing_area, btm_drawing_area) =
        get_drawing_areas(pixel_buf.borrow_mut(), width, height);

    let top_chart = draw_chart(
        top_drawing_area,
        x_range_top,
        y_range_top,
        "time (seconds)",
        "amplitude",
    );
    let btm_chart = draw_chart(btm_drawing_area, x_range_btm, y_range_btm, x_desc, y_desc);

    // unborrow "pixel_buf" again
    //drop(root_drawing_area);

    window
        .update_with_buffer(pixel_buf.borrow(), width, height)
        .unwrap();

    (window, top_chart, btm_chart, pixel_buf)
}

/// Returns two drawing areas, that together fill the whole window.
/// Upper: original audio data
/// Lower: transformed audio data
pub fn get_drawing_areas(
    pixel_buf: &mut [u8],
    width: usize,
    height: usize,
) -> (
    DrawingArea<BitMapBackend<BGRXPixel>, Shift>,
    DrawingArea<BitMapBackend<BGRXPixel>, Shift>,
) {
    // BGRXPixel format required by "minifb" (alpha, red, green, blue)
    let root_drawing_area = BitMapBackend::<BGRXPixel>::with_buffer_and_format(
        pixel_buf.borrow_mut(),
        (width as u32, height as u32),
    )
    .unwrap()
    .into_drawing_area();

    let (top_drawing_area, btm_drawing_area) =
        root_drawing_area.split_vertically((height / 2) as f64);
    (top_drawing_area, btm_drawing_area)
}

/// Draws the initial, empty into the dedicated drawing area.
/// Drops the drawing area, which is important to let this compile.
/// It's important that the chart gets returned as `ChartState`.
///
/// I don't understand it correctly, but it seems that the chart state is
/// a strategy by `plotter` to retain some state while not borrowing anything.
/// Furthermore this is more efficient, because axis etc. doesn't has to be
/// redrawn on incremental updates.
fn draw_chart<'a>(
    drawing_area: DrawingArea<BitMapBackend<BGRXPixel>, Shift>,
    x_range: Range<f64>,
    y_range: Range<f64>,
    x_desc: &'a str,
    y_desc: &'a str,
) -> ChartState<Cartesian2d<RangedCoordf64, RangedCoordf64>> {
    let mut chart = ChartBuilder::on(&drawing_area)
        // margin effects the distance to the border of the window of the chart
        .margin(10)
        .set_all_label_area_size(60)
        .build_cartesian_2d(x_range, y_range)
        .unwrap();

    chart
        .configure_mesh()
        .label_style(("sans-serif", 15).into_font().color(&WHITE))
        .x_desc(x_desc)
        .y_desc(y_desc)
        .x_labels(10)
        .y_labels(10)
        .axis_style(&WHITE)
        .draw()
        .unwrap();

    chart.into_chart_state()
}

#[cfg(test)]
mod tests {

    use minifb::Key;

    #[ignore]
    #[test]
    fn test_minifb_window() {
        let (mut window, _, _, _) = super::setup_window(
            "Test",
            None,
            None,
            Some(-5.0..0.0),
            Some(0.0..5.01),
            "x-axis",
            "y-axis",
            (44100 * 5_usize).next_power_of_two(),
            1.0 / 44100.0,
        );
        while window.is_open() && !window.is_key_down(Key::Escape) {
            // REQUIRED to get keyboard and mouse events (such as close)
            window.update();
        }
    }
}