ytLlive/ViewModels/index.md

ViewModels — index

MVVM layer. See schema.md for the memory-map conventions.

File	Purpose
MainViewModel.cs	The app brain: scenes/elements collections + commands, stream state (IsLive/IsOffline/IsConnected), chat feed, overlays, layout save/open, resolution dropdown (QualityOptions, SelectedQuality, ResolutionHelp, ApplyStreamQuality) that computes the output rect over the 1920×1080 master (OutputRectX/Y/W/H, DimRects, IsOutputCropped, ResolutionBadgeText). Auth: loads the saved DPAPI session at startup (LoadSavedSessionAsync), SignInAsync feeds the GoLive dialog; End Livestream signs out (StopStream clears session + token — crash-safe). Connected account: top-bar avatar/name (AccountAvatarUrl/AccountDisplayName via SyncConnectedAccount, cleared on End). Audio (KISS — the mic is the creator's only audio control; capture SHIPPED, runs for the app's lifetime so the meters preview live): the sound meter is a READ-ONLY realtime level display: fill = Math.Min(1, AudioLevelMeter.ToDisplay((float)AudioLevel) * MicVolume) (MeterFillWidth/MeterBrush, green→yellow→red, zone markers at 60%/80% — ToDisplay maps the raw linear RMS onto a −60..0 dBFS scale so real speech/game levels actually occupy the bar), where AudioLevel (live input, 0 with no input) is fed by the audio mixer once capture lands and MicVolume acts as a gain on ambient noise; while the slider is dragged the bar previews the slider position (SetVolumeAdjusting), returning to the live level on release (0 with no input — clicking the meter does nothing); MicVolume (default 0.8) + read-only MicMuted/MicMuteText/ToggleMicMuteCommand — MicVolume drives MicMuted (muted ⇔ volume 0): sliding to 0 flips the speaker to muted, sliding up from 0 clears it; muting stores the prior volume, unmuting restores it (default 0.8 if unknown) and flashes the meter to the restored position ~300ms (BeginVolumeFlash/EndVolumeFlash); MicSourceName = picked voice source, shown left-justified inside the meter bar (the fill runs at 75% opacity so the text + ruler markings show through); OpenMicPickerCommand/PickMicrophone() open the MicPickerDialog (a picked device takes effect immediately — PickMicrophone swaps the live source via _audioMixer.RestartMic(), loopback keeps running); the MIC label is a button (OpenMicPickerCommand) with a status dot (MicStatus, Models/MicStatus: green = MicConnected via the source's Started event, yellow = MicFailed — in use/unplugged, red = no mic device at startup; MicStatusBrush/MicStatusToolTip); capture starts once at startup (StartMicCaptureAsync) — NOT go-live (BeginGoLive/StopStream no longer touch the mixer) — zero devices = red dot + the mixer never starts. Game audio bar (desktop/game, overlaid at the bottom of the preview window — bottom-center chip, a mirror of the mic bar): IsGameAudioBarVisible (shown only while a full-screen game is producing sound — the VM polls IGameAudioDetector via the default GameAudioDetector every 250ms (_gameAudioTimer); the pure GameAudioHysteresis SHOWs after ~500ms of fullscreen+sound, HIDEs ~1s after leaving fullscreen, and silence never hides an active bar), GameAudioLevel (loopback meter via LoopbackLevelChanged, scaled by volume), GameMuted/GameMuteText/ToggleGameMuteCommand, GameAudioVolume (0..1 volume slider), Begin/End/CancelGameVolumeFlash (mirrors the mic bar's volume flash); the game speaker + slider share the mic bar's PreviewMouseLeftButtonDown/Up + LostMouseCapture code-behind pattern. Webcam: owns CameraManager (MediaCapture), AddWebcamToActiveSceneAsync (picker → default 480×270 bottom-right placement → acquire; the Windows camera picker ALWAYS opens so the creator chooses — never silently reuses the previous camera; picking a different camera swaps the app-wide identity via SwapWebcamIdentityAsync, same path as ChangeWebcamAsync; propagates the running shared bitmap via CameraManager.GetPreviewBitmap first, so a webcam added mid-session never renders a transparent container; greys out when the active scene already has a config via CanAddWebcamToActiveScene), ChangeWebcamAsync (device swap — ReleaseAllAsync old + re-acquire), ShowWebcamInActiveScene (reveal hidden config / empty-canvas right-click), ReacquireWebcam after layout load (re-propagates the shared bitmap to every config), OnCameraPreviewBitmapChanged forwards the shared bitmap into every WebcamSceneConfig.VideoImageSource; SelectedElement drives the preview overlay + internal ClampWebcamToBounds(config, sceneName) (per-scene size cap seam: 50%-per-dimension everywhere, half-screen-AREA in Chat via MaxWebcamWidthFor/MaxWebcamHeightFor). Scenes (five-scene catalog): empty DB seeds Starting/Live/BRB/Chat/Ending (SceneCatalog.All); AddScene(name) accepts only canonical, missing names; MissingScenes/ShowAddScene drive the "+" button (hidden once all five exist; its menu lists only the missing scenes via AddSceneCommand). Screen backdrop (Live-only by policy): owns ScreenCaptureManager + ScreenCaptureSourceFactory (WinRT GraphicsCapture), internal static EnsureBackdrop heals one per backdrop-enabled scene (gated on Scene.HasBackdrop), ReacquireScreenCaptures/RefreshBackdropAutoCapture/NoteBackgroundWindow key by full-screen game monitor or the primary display via Win32FullScreenDetector (GetDisplays()/PrimaryMonitorIndex()), ChangeBackdropCaptureAsync (OS picker) + SetBackdropCapture(DisplayInfo) (in-app "Capture Display"), RedesignateBackdropAsync re-targets all backdrops and releases orphaned sessions, internal static EnforceBackdropPolicy normalizes Scene.HasBackdrop by name on every load + strips lingering non-Live backdrops, CanChangeBackdrop gates the capture menu to Live (the only scene with a backdrop), BackdropImage hides the preview watermark (ShowPreviewPlaceholder)
GoLiveViewModel.cs	Start Stream dialog: account row (saved channel shown with Change Account, or Sign in to YouTube; Start gated on IsSignedIn/IsBusy) + title/description/visibility, start/cancel requests
ReuseImageViewModel.cs	Add Image dialog: candidate list (ReuseImageCandidate), reuse/new/cancel
CameraPickerViewModel.cs	Add Webcam dialog: async camera list (loading / has / none states), UseRequested(CameraDeviceInfo)/CancelRequested
MicPickerViewModel.cs	Select Microphone dialog (voice source): async mic list (loading / has / none states), UseRequested(MicrophoneDeviceInfo)/CancelRequested
SocialsDialogViewModel.cs	Social Media Site Promotion dialog (six fixed slots, SocialSlotViewModel): row 0 = YouTube sign-in gate (sign-in provider fills the channel, delete = sign-out); rows 1-5 validated entries / empty / freemium locks 2-5 (isPremium seam); DetectService → ISocialValidator on confirm (input snaps to text + real logo on success, red do-not + stays editable on failure); CanSave blocked while any slot edits/validates/errors; BarEnabled switch; commit via CommittedEntries + BuildSocialsConfig() (YouTube first) + SaveRequested/CancelRequested. WPF-free — the window owns the dialogs (delete confirm, sign-in gate) and calls StartEdit/ConfirmEdit/DeleteSlotAsync.

Related: Models/index.md for the data; Services/index.md for what the ViewModels drive; base class in Helpers/ViewModelBase.cs.