Hololens - Show/hide media controls according to playback state

support/hololens/ServoApp/BrowserPage.cpp

@@ -70,6 +70,20 @@ void BrowserPage::BindServoEvents() {
   servoControl().OnCaptureGesturesEnded(
       [=] { navigationBar().IsHitTestVisible(true); });
   urlTextbox().GotFocus(std::bind(&BrowserPage::OnURLFocused, this, _1));
+  servoControl().OnMediaSessionMetadata(
+      [=](hstring title, hstring artist, hstring album) {});
+  servoControl().OnMediaSessionPlaybackStateChange([=](const auto &,
+                                                       int state) {
+    if (state == 1 /* none */) {
+      mediaControls().Visibility(Visibility::Collapsed);
+      return;
+    }
+    mediaControls().Visibility(Visibility::Visible);
+    playButton().Visibility(state == 3 /* paused */ ? Visibility::Visible
+                                                    : Visibility::Collapsed);
+    pauseButton().Visibility(state == 3 /* paused */ ? Visibility::Collapsed
+                                                     : Visibility::Visible);
+  });
 }
 
 void BrowserPage::OnURLFocused(Windows::Foundation::IInspectable const &) {

support/hololens/ServoApp/BrowserPage.xaml

@@ -137,9 +137,9 @@
                 <Button Margin="0,10,10,0" Click="OnXRPkgWarningDismissClick">Dismiss</Button>
             </StackPanel>
         </StackPanel>
-        <CommandBar Grid.Row="3" Visibility="Collapsed">
-            <AppBarButton Icon="Play" Label="Play" Click="OnMediaControlsPlayClicked"/>
-            <AppBarButton Icon="Pause" Label="Pause" Click="OnMediaControlsPauseClicked"/>
+        <CommandBar Grid.Row="3" x:Name="mediaControls" Visibility="Collapsed">
+            <AppBarButton Icon="Play" Label="Play" x:Name="playButton" Visibility="Collapsed" Click="OnMediaControlsPlayClicked"/>
+            <AppBarButton Icon="Pause" Label="Pause" x:Name="pauseButton" Click="OnMediaControlsPauseClicked"/>
 
             <CommandBar.Content>
                 <TextBlock Text="Now playing..." Margin="12,14"/>

support/hololens/ServoApp/ServoControl/Servo.cpp

@@ -56,6 +56,16 @@ const char *get_clipboard_contents() {
   return nullptr;
 }
 
+void on_media_session_metadata(const char *title, const char *album,
+                               const char *artist) {
+  return sServo->Delegate().OnServoMediaSessionMetadata(
+      char2hstring(title), char2hstring(album), char2hstring(artist));
+}
+
+void on_media_session_playback_state_change(const int state) {
+  return sServo->Delegate().OnServoMediaSessionPlaybackStateChange(state);
+}
+
 Servo::Servo(hstring url, hstring args, GLsizei width, GLsizei height,
              float dpi, ServoDelegate &aDelegate)
     : mWindowHeight(height), mWindowWidth(width), mDelegate(aDelegate) {
@@ -63,7 +73,8 @@ Servo::Servo(hstring url, hstring args, GLsizei width, GLsizei height,
   capi::CInitOptions o;
   hstring defaultPrefs = L" --pref dom.webxr.enabled";
   o.args = *hstring2char(args + defaultPrefs);
-  o.url = *hstring2char(url);
+  o.url =
+      "https://ferjm.github.io/web-api-tests/video/mp4.html"; //*hstring2char(url);
   o.width = mWindowWidth;
   o.height = mWindowHeight;
   o.density = dpi;
@@ -110,6 +121,9 @@ Servo::Servo(hstring url, hstring args, GLsizei width, GLsizei height,
   c.on_ime_state_changed = &on_ime_state_changed;
   c.get_clipboard_contents = &get_clipboard_contents;
   c.set_clipboard_contents = &set_clipboard_contents;
+  c.on_media_session_metadata = &on_media_session_metadata;
+  c.on_media_session_playback_state_change =
+      &on_media_session_playback_state_change;
 
   capi::register_panic_handler(&on_panic);
 

support/hololens/ServoApp/ServoControl/Servo.h

@@ -36,6 +36,8 @@ public:
   virtual void OnServoIMEStateChanged(bool) = 0;
   virtual void Flush() = 0;
   virtual void MakeCurrent() = 0;
+  virtual void OnServoMediaSessionMetadata(hstring, hstring, hstring) = 0;
+  virtual void OnServoMediaSessionPlaybackStateChange(int) = 0;
 
 protected:
   virtual ~ServoDelegate(){};

support/hololens/ServoApp/ServoControl/ServoControl.cpp

@@ -432,6 +432,15 @@ void ServoControl::OnServoIMEStateChanged(bool aShow) {
   // https://docs.microsoft.com/en-us/windows/win32/winauto/uiauto-implementingtextandtextrange
 }
 
+void ServoControl::OnServoMediaSessionMetadata(hstring title, hstring artist,
+                                               hstring album) {
+  RunOnUIThread([=] { mOnMediaSessionMetadataEvent(title, artist, album); });
+}
+
+void ServoControl::OnServoMediaSessionPlaybackStateChange(int state) {
+  RunOnUIThread([=] { mOnMediaSessionPlaybackStateChangeEvent(*this, state); });
+}
+
 template <typename Callable> void ServoControl::RunOnUIThread(Callable cb) {
   Dispatcher().RunAsync(CoreDispatcherPriority::High, cb);
 }

support/hololens/ServoApp/ServoControl/ServoControl.h

@@ -70,6 +70,23 @@ struct ServoControl : ServoControlT<ServoControl>, public servo::ServoDelegate {
     mOnCaptureGesturesEndedEvent.remove(token);
   }
 
+  winrt::event_token
+  OnMediaSessionMetadata(MediaSessionMetadataDelegate const &handler) {
+    return mOnMediaSessionMetadataEvent.add(handler);
+  };
+  void OnMediaSessionMetadata(winrt::event_token const &token) noexcept {
+    mOnMediaSessionMetadataEvent.remove(token);
+  }
+
+  winrt::event_token OnMediaSessionPlaybackStateChange(
+      Windows::Foundation::EventHandler<int> const &handler) {
+    return mOnMediaSessionPlaybackStateChangeEvent.add(handler);
+  };
+  void
+  OnMediaSessionPlaybackStateChange(winrt::event_token const &token) noexcept {
+    mOnMediaSessionPlaybackStateChangeEvent.remove(token);
+  }
+
   void SetTransientMode(bool transient) { mTransient = transient; }
 
   void SetArgs(hstring args) { mArgs = args; }
@@ -87,6 +104,9 @@ struct ServoControl : ServoControlT<ServoControl>, public servo::ServoDelegate {
   virtual bool OnServoAllowNavigation(winrt::hstring);
   virtual void OnServoAnimatingChanged(bool);
   virtual void OnServoIMEStateChanged(bool);
+  virtual void OnServoMediaSessionMetadata(winrt::hstring, winrt::hstring,
+                                           winrt::hstring);
+  virtual void OnServoMediaSessionPlaybackStateChange(int);
 
 private:
   winrt::event<Windows::Foundation::EventHandler<hstring>> mOnURLChangedEvent;
@@ -96,6 +116,9 @@ private:
   winrt::event<EventDelegate> mOnLoadEndedEvent;
   winrt::event<EventDelegate> mOnCaptureGesturesStartedEvent;
   winrt::event<EventDelegate> mOnCaptureGesturesEndedEvent;
+  winrt::event<MediaSessionMetadataDelegate> mOnMediaSessionMetadataEvent;
+  winrt::event<Windows::Foundation::EventHandler<int>>
+      mOnMediaSessionPlaybackStateChangeEvent;
 
   float mDPI = 1;
   hstring mInitialURL = DEFAULT_URL;

support/hololens/ServoApp/ServoControl/ServoControl.idl

@@ -2,6 +2,7 @@ namespace ServoApp {
 
   delegate void EventDelegate();
   delegate void HistoryChangedDelegate(Boolean back, Boolean forward);
+  delegate void MediaSessionMetadataDelegate(String title, String artist, String album);
 
   runtimeclass ServoControl : Windows.UI.Xaml.Controls.Control {
       ServoControl();
@@ -20,5 +21,7 @@ namespace ServoApp {
       event HistoryChangedDelegate OnHistoryChanged;
       event Windows.Foundation.EventHandler<String> OnTitleChanged;
       event Windows.Foundation.EventHandler<String> OnURLChanged;
+	  event MediaSessionMetadataDelegate OnMediaSessionMetadata;
+	  event Windows.Foundation.EventHandler<int> OnMediaSessionPlaybackStateChange;
 }
 } // namespace ServoApp