azul_layout/widgets/
camera.rs

1//! Camera-preview widget - a "dumb widget" (like [`MapWidget`](super::map))
2//! that owns a background capture thread + a GL-texture `ImageRef`, with **no**
3//! camera-specific logic in the core framework (SUPER_PLAN_2 §4 P6, widget
4//! pivot - see the MASTER PLAN in `MOBILE_SESSION_LOG.md`).
5//!
6//! `CameraWidget::create(config).dom()` -> a static `<img>` whose pixels a
7//! background thread keeps fed. On `AfterMount` the capture thread starts
8//! (`CallbackInfo::add_thread`); each frame goes through
9//! [`super::capture_common::present_frame`], which uploads it into a stable
10//! external GL texture + recomposites - no relayout, no display-list rebuild.
11//! The shared thread/writeback/GL core lives in `capture_common`; this widget
12//! is just its config + worker.
13//!
14//! This tick uses a self-contained **test-pattern** worker (colour cycle, no
15//! platform deps); the real AVFoundation/Camera2 worker (dll-side) swaps in
16//! later.
17
18use alloc::vec::Vec;
19
20use azul_core::callbacks::Update;
21use azul_core::camera::CameraConfig;
22use azul_core::dom::{ComponentEventFilter, DatasetMergeCallbackType, Dom, EventFilter};
23use azul_core::refany::{OptionRefAny, RefAny};
24use azul_core::resources::{ImageRef, RawImageFormat};
25use azul_core::task::{ThreadId, ThreadReceiver};
26
27use azul_core::video::VideoFrame;
28
29use super::capture_common::{
30    camera_backend, invoke_on_frame, present_frame, OnVideoFrame, OnVideoFrameCallback,
31    OptionOnVideoFrame,
32};
33use crate::callbacks::{Callback, CallbackInfo, CallbackType};
34use crate::thread::{
35    Thread, ThreadCallback, ThreadReceiveMsg, ThreadSender, ThreadWriteBackMsg, WriteBackCallback,
36};
37
38/// Init data handed to the capture worker thread.
39struct CameraThreadInit {
40    width: u32,
41    height: u32,
42}
43
44/// Live state for one camera widget, carried across relayout by
45/// [`merge_camera_state`].
46pub struct CameraWidgetState {
47    /// The requested capture configuration (the control POD).
48    pub config: CameraConfig,
49    /// `true` once the capture thread has been started.
50    pub started: bool,
51    /// The stable external GL texture id once the first frame installed it.
52    pub gl_texture_id: Option<u32>,
53    /// Optional user hook invoked with each captured frame (effects / save /
54    /// send). Re-set on every fresh build (see [`merge_camera_state`]).
55    pub on_frame: OptionOnVideoFrame,
56}
57
58/// A camera-preview widget. `create(config).dom()` yields an `<img>` the
59/// capture thread keeps fed.
60#[repr(C)]
61pub struct CameraWidget {
62    /// Requested capture config (camera facing, resolution, fps, format).
63    pub config: CameraConfig,
64    /// Optional per-frame user hook (effects / save / send - azul-meet).
65    pub on_frame: OptionOnVideoFrame,
66}
67
68impl CameraWidget {
69    /// Create a camera widget for the given capture config.
70    pub fn create(config: CameraConfig) -> Self {
71        Self {
72            config,
73            on_frame: OptionOnVideoFrame::None,
74        }
75    }
76
77    /// Set a hook invoked with every captured frame - for live effects, saving
78    /// frames into your data model, or sending them over the network
79    /// (azul-meet). The backreference DI pattern (see `architecture.md`).
80    pub fn set_on_frame<C: Into<OnVideoFrameCallback>>(&mut self, data: RefAny, on_frame: C) {
81        self.on_frame = Some(OnVideoFrame {
82            refany: data,
83            callback: on_frame.into(),
84        })
85        .into();
86    }
87
88    /// Builder form of [`set_on_frame`](Self::set_on_frame).
89    pub fn with_on_frame<C: Into<OnVideoFrameCallback>>(
90        mut self,
91        data: RefAny,
92        on_frame: C,
93    ) -> Self {
94        self.set_on_frame(data, on_frame);
95        self
96    }
97
98    /// Build the widget's DOM: a single `<img>` node, fed by a background
99    /// capture thread started on mount.
100    pub fn dom(self) -> Dom {
101        let state = CameraWidgetState {
102            config: self.config,
103            started: false,
104            gl_texture_id: None,
105            on_frame: self.on_frame,
106        };
107        let dataset = RefAny::new(state);
108
109        let (w, h) = frame_dims(&self.config);
110        let placeholder = ImageRef::null_image(
111            w as usize,
112            h as usize,
113            RawImageFormat::BGRA8,
114            b"azul-camera-placeholder".to_vec(),
115        );
116
117        Dom::create_image(placeholder)
118            .with_dataset(OptionRefAny::Some(dataset.clone()))
119            .with_merge_callback(merge_camera_state as DatasetMergeCallbackType)
120            .with_callback(
121                EventFilter::Component(ComponentEventFilter::AfterMount),
122                dataset,
123                Callback::from(camera_on_after_mount as CallbackType),
124            )
125    }
126}
127
128/// Frame dimensions for a config (0 -> a sane default).
129fn frame_dims(config: &CameraConfig) -> (u32, u32) {
130    let w = if config.width > 0 { config.width } else { 640 };
131    let h = if config.height > 0 { config.height } else { 480 };
132    (w, h)
133}
134
135/// AfterMount: start the background capture thread exactly once.
136extern "C" fn camera_on_after_mount(mut data: RefAny, mut info: CallbackInfo) -> Update {
137    let dims = {
138        let mut s = match data.downcast_mut::<CameraWidgetState>() {
139            Some(s) => s,
140            None => return Update::DoNothing,
141        };
142        if s.started {
143            return Update::DoNothing;
144        }
145        s.started = true;
146        frame_dims(&s.config)
147    };
148
149    info.add_thread(
150        ThreadId::unique(),
151        Thread::create(
152            RefAny::new(CameraThreadInit {
153                width: dims.0,
154                height: dims.1,
155            }),
156            data.clone(),
157            ThreadCallback::new(camera_worker),
158        ),
159    );
160    Update::DoNothing
161}
162
163/// Background worker (test pattern): a colour-cycling solid frame ~30x/s until
164/// the widget unmounts. The real AVFoundation/Camera2 capture loop replaces it.
165extern "C" fn camera_worker(mut init: RefAny, mut sender: ThreadSender, _recv: ThreadReceiver) {
166    let (w, h) = init
167        .downcast_ref::<CameraThreadInit>()
168        .map(|i| (i.width, i.height))
169        .unwrap_or((640, 480));
170
171    // Real platform capture if the dll registered a camera backend (v4l2 /
172    // AVFoundation / Media Foundation); otherwise the colour-cycle test pattern.
173    if let Some(backend) = camera_backend() {
174        let handle = (backend.open)(0, w, h);
175        if handle != 0 {
176            let mut buf: alloc::vec::Vec<u8> = alloc::vec::Vec::new();
177            loop {
178                let (fw, fh) = (backend.read)(handle, &mut buf);
179                if fw == 0 || fh == 0 {
180                    break;
181                }
182                let frame = VideoFrame {
183                    width: fw,
184                    height: fh,
185                    bytes: buf.clone().into(),
186                };
187                if !sender.send(ThreadReceiveMsg::WriteBack(ThreadWriteBackMsg::new(
188                    WriteBackCallback::new(camera_writeback),
189                    RefAny::new(frame),
190                ))) {
191                    break;
192                }
193            }
194            (backend.close)(handle);
195            return;
196        }
197    }
198
199    let px = (w as usize) * (h as usize);
200    let mut tick: u32 = 0;
201    loop {
202        let color = [
203            (tick % 256) as u8,
204            (tick.wrapping_mul(2) % 256) as u8,
205            (tick.wrapping_mul(3) % 256) as u8,
206            255u8,
207        ];
208        let mut bytes = Vec::with_capacity(px * 4);
209        for _ in 0..px {
210            bytes.extend_from_slice(&color);
211        }
212        let frame = VideoFrame {
213            width: w,
214            height: h,
215            bytes: bytes.into(),
216        };
217        let sent = sender.send(ThreadReceiveMsg::WriteBack(ThreadWriteBackMsg::new(
218            WriteBackCallback::new(camera_writeback),
219            RefAny::new(frame),
220        )));
221        if !sent {
222            break;
223        }
224        std::thread::sleep(std::time::Duration::from_millis(33));
225        tick = tick.wrapping_add(8);
226    }
227}
228
229/// Writeback (main thread): hand the frame to the shared GL presenter and
230/// store the (stable) texture id back in the widget's state.
231extern "C" fn camera_writeback(
232    mut writeback_data: RefAny,
233    mut frame_data: RefAny,
234    mut info: CallbackInfo,
235) -> Update {
236    let (current, hook) = match writeback_data.downcast_ref::<CameraWidgetState>() {
237        Some(s) => (s.gl_texture_id, s.on_frame.clone()),
238        None => (None, OptionOnVideoFrame::None),
239    };
240    let mut user_update = Update::DoNothing;
241    let new_id = match frame_data.downcast_ref::<VideoFrame>() {
242        Some(frame) => {
243            let id = present_frame(&mut info, writeback_data.clone(), current, &frame);
244            user_update = invoke_on_frame(&hook, &mut info, &frame);
245            id
246        }
247        None => return Update::DoNothing,
248    };
249    if let Some(mut s) = writeback_data.downcast_mut::<CameraWidgetState>() {
250        s.gl_texture_id = new_id;
251    }
252    user_update
253}
254
255/// Carry live state forward across relayout (config from the fresh build,
256/// thread / texture from the previous frame).
257extern "C" fn merge_camera_state(mut new_data: RefAny, mut old_data: RefAny) -> RefAny {
258    {
259        let new_guard = new_data.downcast_mut::<CameraWidgetState>();
260        let old_guard = old_data.downcast_ref::<CameraWidgetState>();
261        if let (Some(mut new_g), Some(old_g)) = (new_guard, old_guard) {
262            new_g.started = old_g.started;
263            new_g.gl_texture_id = old_g.gl_texture_id;
264        }
265    }
266    new_data
267}
azul_layout/widgets/camera.rs

azul_layout/widgets/
camera.rs
