azul_layout/widgets/
video.rs

1//! Video-playback widget — a "dumb widget" identical in architecture to the
2//! [`CameraWidget`](super::camera) / [`ScreenCaptureWidget`](super::screencap),
3//! only the source differs (a video URL/file decoded via vk-video).
4//! SUPER_PLAN_2 §4 P6, widget pivot.
5//!
6//! `VideoWidget::create(config).dom()` → an `<img>` a background decode thread
7//! keeps fed; each frame goes through [`super::capture_common::present_frame`]
8//! (GL-texture install-once / re-upload + recomposite). Shared core in
9//! `capture_common`; this widget is its config + worker. Test-pattern worker
10//! (scrolling SMPTE colour bars) stands in for the real vk-video decode worker.
11
12use alloc::vec::Vec;
13
14use azul_core::callbacks::Update;
15use azul_core::dom::{ComponentEventFilter, DatasetMergeCallbackType, Dom, EventFilter};
16use azul_core::refany::{OptionRefAny, RefAny};
17use azul_core::resources::{ImageRef, RawImageFormat};
18use azul_core::task::{ThreadId, ThreadReceiver};
19use azul_core::video::{VideoConfig, VideoFrame};
20
21use super::capture_common::{
22    invoke_on_frame, present_frame, OnVideoFrame, OnVideoFrameCallback, OptionOnVideoFrame,
23};
24use crate::callbacks::{Callback, CallbackInfo, CallbackType};
25use crate::thread::{
26    Thread, ThreadCallback, ThreadReceiveMsg, ThreadSender, ThreadWriteBackMsg, WriteBackCallback,
27};
28
29/// Default decode size for the test pattern (the real decoder reports the
30/// stream's actual size).
31const DEFAULT_W: u32 = 1280;
32const DEFAULT_H: u32 = 720;
33
34/// Live state for one video widget, carried across relayout by
35/// [`merge_video_state`].
36pub struct VideoWidgetState {
37    /// The requested playback configuration (source + autoplay/loop).
38    pub config: VideoConfig,
39    /// `true` once the decode thread has been started.
40    pub started: bool,
41    /// The stable external GL texture id once installed.
42    pub gl_texture_id: Option<u32>,
43    /// Optional user hook invoked with each decoded frame (effects / save /
44    /// send). Re-set on every fresh build (see [`merge_video_state`]).
45    pub on_frame: OptionOnVideoFrame,
46}
47
48/// A video-playback widget. `create(config).dom()` yields an `<img>` the
49/// decode thread keeps fed.
50#[repr(C)]
51pub struct VideoWidget {
52    /// Source URL + autoplay/loop + format.
53    pub config: VideoConfig,
54    /// Optional per-frame user hook (effects / save / send - azul-meet).
55    pub on_frame: OptionOnVideoFrame,
56}
57
58impl VideoWidget {
59    /// Create a video widget for the given config.
60    pub fn create(config: VideoConfig) -> Self {
61        Self {
62            config,
63            on_frame: OptionOnVideoFrame::None,
64        }
65    }
66
67    /// Set a hook invoked with every decoded frame - for live effects, saving
68    /// frames into your data model, or sending them over the network
69    /// (azul-meet). The backreference DI pattern (see `architecture.md`).
70    pub fn set_on_frame<C: Into<OnVideoFrameCallback>>(&mut self, data: RefAny, on_frame: C) {
71        self.on_frame = Some(OnVideoFrame {
72            refany: data,
73            callback: on_frame.into(),
74        })
75        .into();
76    }
77
78    /// Builder form of [`set_on_frame`](Self::set_on_frame).
79    pub fn with_on_frame<C: Into<OnVideoFrameCallback>>(
80        mut self,
81        data: RefAny,
82        on_frame: C,
83    ) -> Self {
84        self.set_on_frame(data, on_frame);
85        self
86    }
87
88    /// Build the widget's DOM: a single `<img>` node, fed by a background
89    /// decode thread started on mount.
90    pub fn dom(self) -> Dom {
91        let state = VideoWidgetState {
92            config: self.config,
93            started: false,
94            gl_texture_id: None,
95            on_frame: self.on_frame,
96        };
97        let dataset = RefAny::new(state);
98
99        let placeholder = ImageRef::null_image(
100            DEFAULT_W as usize,
101            DEFAULT_H as usize,
102            RawImageFormat::BGRA8,
103            b"azul-video-placeholder".to_vec(),
104        );
105
106        Dom::create_image(placeholder)
107            .with_dataset(OptionRefAny::Some(dataset.clone()))
108            .with_merge_callback(merge_video_state as DatasetMergeCallbackType)
109            .with_callback(
110                EventFilter::Component(ComponentEventFilter::AfterMount),
111                dataset,
112                Callback::from(video_on_after_mount as CallbackType),
113            )
114    }
115}
116
117/// AfterMount: start the background decode thread exactly once.
118extern "C" fn video_on_after_mount(mut data: RefAny, mut info: CallbackInfo) -> Update {
119    {
120        let mut s = match data.downcast_mut::<VideoWidgetState>() {
121            Some(s) => s,
122            None => return Update::DoNothing,
123        };
124        if s.started {
125            return Update::DoNothing;
126        }
127        s.started = true;
128    }
129    info.add_thread(
130        ThreadId::unique(),
131        Thread::create(
132            RefAny::new(()),
133            data.clone(),
134            ThreadCallback::new(video_test_worker),
135        ),
136    );
137    Update::DoNothing
138}
139
140/// Background worker (test pattern): SMPTE-style colour bars scrolling
141/// horizontally ~30×/s. Replaced by the real vk-video decode worker later.
142extern "C" fn video_test_worker(_init: RefAny, mut sender: ThreadSender, _recv: ThreadReceiver) {
143    const BARS: [[u8; 3]; 7] = [
144        [235, 235, 235],
145        [235, 235, 16],
146        [16, 235, 235],
147        [16, 235, 16],
148        [235, 16, 235],
149        [235, 16, 16],
150        [16, 16, 235],
151    ];
152    let (w, h) = (DEFAULT_W as usize, DEFAULT_H as usize);
153    let mut tick: u32 = 0;
154    loop {
155        let shift = (tick as usize / 4) % 7;
156        let mut bytes = Vec::with_capacity(w * h * 4);
157        for _y in 0..h {
158            for x in 0..w {
159                let c = BARS[((x * 7 / w) + shift) % 7];
160                bytes.extend_from_slice(&[c[0], c[1], c[2], 255]);
161            }
162        }
163        let frame = VideoFrame {
164            width: w as u32,
165            height: h as u32,
166            bytes: bytes.into(),
167        };
168        let sent = sender.send(ThreadReceiveMsg::WriteBack(ThreadWriteBackMsg::new(
169            WriteBackCallback::new(video_writeback),
170            RefAny::new(frame),
171        )));
172        if !sent {
173            break;
174        }
175        std::thread::sleep(std::time::Duration::from_millis(33));
176        tick = tick.wrapping_add(2);
177    }
178}
179
180/// Writeback (main thread): hand the decoded frame to the shared GL presenter
181/// and store the (stable) texture id.
182extern "C" fn video_writeback(
183    mut writeback_data: RefAny,
184    mut frame_data: RefAny,
185    mut info: CallbackInfo,
186) -> Update {
187    let (current, hook) = match writeback_data.downcast_ref::<VideoWidgetState>() {
188        Some(s) => (s.gl_texture_id, s.on_frame.clone()),
189        None => (None, OptionOnVideoFrame::None),
190    };
191    let mut user_update = Update::DoNothing;
192    let new_id = match frame_data.downcast_ref::<VideoFrame>() {
193        Some(frame) => {
194            let id = present_frame(&mut info, writeback_data.clone(), current, &frame);
195            user_update = invoke_on_frame(&hook, &mut info, &frame);
196            id
197        }
198        None => return Update::DoNothing,
199    };
200    if let Some(mut s) = writeback_data.downcast_mut::<VideoWidgetState>() {
201        s.gl_texture_id = new_id;
202    }
203    user_update
204}
205
206/// Carry live state forward across relayout.
207extern "C" fn merge_video_state(mut new_data: RefAny, mut old_data: RefAny) -> RefAny {
208    {
209        let new_guard = new_data.downcast_mut::<VideoWidgetState>();
210        let old_guard = old_data.downcast_ref::<VideoWidgetState>();
211        if let (Some(mut new_g), Some(old_g)) = (new_guard, old_guard) {
212            new_g.started = old_g.started;
213            new_g.gl_texture_id = old_g.gl_texture_id;
214        }
215    }
216    new_data
217}
azul_layout/widgets/video.rs

azul_layout/widgets/
video.rs
