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render_subtitle/
render_subtitle.rs

1//! Example demonstrating subtitle rendering.
2
3use oximedia_codec::VideoFrame;
4use oximedia_core::{PixelFormat, Rational, Timestamp};
5use oximedia_subtitle::{parser::srt, Alignment, Color, OutlineStyle, Position, SubtitleStyle};
6
7fn main() -> Result<(), Box<dyn std::error::Error>> {
8    // Example SRT subtitle data
9    let srt_data = r"1
1000:00:01,000 --> 00:00:04,000
11Hello, World!
12
132
1400:00:05,000 --> 00:00:08,000
15This is a subtitle example
16with multiple lines.
17
183
1900:00:10,000 --> 00:00:13,000
20<i>Styled subtitle with HTML tags</i>
21";
22
23    // Parse SRT subtitles
24    let subtitles = srt::parse(srt_data.as_bytes())?;
25    println!("Parsed {} subtitles", subtitles.len());
26
27    for (i, subtitle) in subtitles.iter().enumerate() {
28        println!(
29            "Subtitle {}: {}ms - {}ms: {}",
30            i + 1,
31            subtitle.start_time,
32            subtitle.end_time,
33            subtitle.text
34        );
35    }
36
37    // Create a sample video frame
38    let mut frame = VideoFrame::new(PixelFormat::Rgb24, 1920, 1080);
39    frame.allocate();
40
41    // Fill with blue background
42    if let Some(plane) = frame.planes.get_mut(0) {
43        let data_len = plane.data.len();
44        let mut new_data = vec![0u8; data_len];
45        for pixel in new_data.chunks_exact_mut(3) {
46            pixel[0] = 0; // R
47            pixel[1] = 0; // G
48            pixel[2] = 100; // B
49        }
50        plane.data = new_data;
51    }
52
53    // Note: In a real application, you would load a font file
54    // For this example, we'll show how to create the renderer
55    println!("\nTo use the subtitle renderer:");
56    println!("1. Load a font: Font::from_file(\"path/to/font.ttf\")?");
57    println!("2. Configure style with colors, size, outline, etc.");
58    println!("3. Create renderer: SubtitleRenderer::new(font, style)");
59    println!("4. Render: renderer.render_subtitle(&subtitle, &mut frame, timestamp)?");
60
61    // Example style configuration
62    let style = SubtitleStyle::default()
63        .with_font_size(48.0)
64        .with_color(255, 255, 255, 255) // White text
65        .with_outline(OutlineStyle::new(Color::black(), 2.0))
66        .with_position(Position::bottom_center())
67        .with_alignment(Alignment::Center)
68        .with_margins(40, 40, 40, 80);
69
70    println!(
71        "\nStyle configuration: Font size={}, Color=white, Outline=black 2px",
72        style.font_size
73    );
74
75    // Example timestamps
76    let ts1 = Timestamp::new(2000, Rational::new(1, 1000)); // 2 seconds
77    let ts2 = Timestamp::new(6000, Rational::new(1, 1000)); // 6 seconds
78
79    // Show which subtitles would be active at different times
80    for subtitle in &subtitles {
81        #[allow(clippy::cast_possible_truncation)]
82        let ts1_ms = (ts1.to_seconds() * 1000.0).round() as i64;
83        #[allow(clippy::cast_possible_truncation)]
84        let ts2_ms = (ts2.to_seconds() * 1000.0).round() as i64;
85        if subtitle.is_active(ts1_ms) {
86            println!(
87                "\nAt t=2s, active subtitle: '{}'",
88                subtitle.text.lines().next().unwrap_or("")
89            );
90        }
91        if subtitle.is_active(ts2_ms) {
92            println!(
93                "At t=6s, active subtitle: '{}'",
94                subtitle.text.lines().next().unwrap_or("")
95            );
96        }
97    }
98
99    // Example: Write subtitles back to SRT format
100    let output_srt = srt::write(&subtitles)?;
101    println!("\nGenerated SRT output:\n{output_srt}");
102
103    Ok(())
104}