audio_visualizer/waveform/
plotters_png_file.rs

1/*
2MIT License
3
4Copyright (c) 2021 Philipp Schuster
5
6Permission is hereby granted, free of charge, to any person obtaining a copy
7of this software and associated documentation files (the "Software"), to deal
8in the Software without restriction, including without limitation the rights
9to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
10copies of the Software, and to permit persons to whom the Software is
11furnished to do so, subject to the following conditions:
12
13The above copyright notice and this permission notice shall be included in all
14copies or substantial portions of the Software.
15
16THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
17IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
18FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
19AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
20LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
21OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
22SOFTWARE.
23*/
24//! Static waveform visualization which exports the waveform to a PNG file.
25
26use crate::Channels;
27use plotters::prelude::*;
28use std::fs;
29use std::path::PathBuf;
30
31/// Visualizes audio as a waveform in a png file using "plotters" crate.
32/// If the data is stereo, it creates two files (with "left_" and "right_" prefix).
33pub fn waveform_static_plotters_png_visualize(
34    samples: &[i16],
35    channels: Channels,
36    directory: &str,
37    filename: &str,
38) {
39    if channels.is_stereo() {
40        assert_eq!(
41            0,
42            samples.len() % 2,
43            "If stereo is provided, the length of the audio data must be even!"
44        );
45        let (left, right) = channels.stereo_interleavement().to_channel_data(samples);
46        waveform_static_plotters_png_visualize(
47            &left,
48            Channels::Mono,
49            directory,
50            &format!("left_{}", filename),
51        );
52        waveform_static_plotters_png_visualize(
53            &right,
54            Channels::Mono,
55            directory,
56            &format!("right_{}", filename),
57        );
58        return;
59    }
60
61    if !fs::exists(directory).unwrap() {
62        fs::create_dir(directory).unwrap();
63    }
64    let mut path = PathBuf::new();
65    path.push(directory);
66    path.push(filename);
67
68    let mut max = 0;
69    for sample in samples {
70        let sample = *sample as i32;
71        let sample = sample.abs();
72        if sample > max {
73            max = sample;
74        }
75    }
76
77    let width = (samples.len() / 5) as u32;
78    let width = if width > 4000 { 4000 } else { width };
79    let root = BitMapBackend::new(&path, (width, 1000)).into_drawing_area();
80    root.fill(&WHITE).unwrap();
81    let mut chart = ChartBuilder::on(&root)
82        .caption("y=music(t)", ("sans-serif", 50).into_font())
83        .margin(5)
84        .x_label_area_size(30)
85        .y_label_area_size(30)
86        .build_cartesian_2d(0.0..samples.len() as f32, -max as f32..max as f32)
87        .unwrap();
88
89    chart.configure_mesh().draw().unwrap();
90
91    chart
92        .draw_series(LineSeries::new(
93            // (-50..=50).map(|x| x as f32 / 50.0).map(|x| (x, x * x)),
94            samples
95                .iter()
96                .enumerate()
97                .map(|(sample_i, amplitude)| (sample_i as f32, *amplitude as f32)),
98            &RED,
99        ))
100        .unwrap()
101        // .label("y = music(t)")
102        .legend(|(x, y)| PathElement::new(vec![(x, y), (x + 20, y)], RED));
103
104    chart
105        .configure_series_labels()
106        .background_style(WHITE.mix(0.8))
107        .border_style(BLACK)
108        .draw()
109        .unwrap();
110}
111
112#[cfg(test)]
113mod tests {
114    use super::*;
115    use crate::tests::testutil::{decode_mp3, TEST_OUT_DIR, TEST_SAMPLES_DIR};
116    use crate::ChannelInterleavement;
117
118    #[test]
119    fn test_visualize_png_output() {
120        let mut path = PathBuf::new();
121        path.push(TEST_SAMPLES_DIR);
122        path.push("sample_1.mp3");
123
124        let lrlr_mp3_samples = decode_mp3(path.as_path());
125
126        waveform_static_plotters_png_visualize(
127            &lrlr_mp3_samples,
128            Channels::Stereo(ChannelInterleavement::LRLR),
129            TEST_OUT_DIR,
130            "waveform_static_plotters_png_visualize_example.png",
131        );
132    }
133}
audio_visualizer/waveform/plotters_png_file.rs

audio_visualizer/waveform/
plotters_png_file.rs
