The creator's locked table (2026-10-17) gives the Chat scene its own rules in
the 9:16 tier: RECT ONLY - the circle option is not offered - and a size that
is either the normal small tile or ENLARGED to fill one whole 607x540 area
(top or bottom). Unit 1 shipped the per-scene placement; this unit is the Chat
scene's own variant of it.
The rule lives on the MODEL, not on the button:
- Models/SceneElement.cs: ClipShape and ToggleClipShape() are now virtual.
- Models/WebcamSceneConfig.cs: VerticalShapeLocked (set per scene by the VM)
OVERRIDES the ClipShape property, so no writer can slip a circle in - the
toggle, the Shape button and the placement swap all go through it. The lock
is cleared BEFORE the 16:9 layout comes back, so the desktop shape returns.
- ViewModels/MainViewModel.Webcam.cs: CanToggleClipShape (the circle is NOT
offered in the vertical Chat layout - the Shape button disappears, it is not
merely greyed out), IsChatSceneCamera, ResizeWebcamInVerticalTier.
- Models/VerticalCameraLayout.cs: FillsArea (the "enlarged" state, derived -
no new column) and SizeFor - the Chat camera's TWO sizes, the tile or the
whole area, whichever is nearer the requested width, so the resize handle
has two detents instead of any size in between.
- An enlarged camera FILLS the area its centre is in (top or bottom), so
dragging it up/down swaps the areas.
- The Chat camera is auto-tiled like the Live one when the vertical tier is
picked - otherwise the vertical chat stream has no camera at all.
- Controls/PreviewPane.xaml.cs: the resize routes through the VM; the drag
assigns, lets the model clamp into the band, then snaps (so the enlarged
camera can be dragged from the top area to the bottom one).
Test: ytLive.Tests/VerticalChatCameraLayoutTests.cs - the ONE Good Dog test for
the unit: the vertical tier is picked -> the Chat camera comes into the band as
a small RECT tile -> the circle option is not offered and cannot be set even on
the model -> dragged up and enlarged it fills the TOP area exactly -> back to
16:9 the desktop layout is restored exactly and the circle option is offered
again. 430/430 tests pass, 0 warnings.
Research (the creator's table is the established practice, not our invention):
- Streamlabs' vertical guide: "splitting the screen in half horizontally,
placing the camera feed in the top half and the main content on the bottom
(or vice versa) may be the bet", and a just-chatting vertical wants the
camera "to take up most of the screen"
(streamlabs.com/content-hub/post/overlays-vertical-and-horizontal-streaming)
- Bloopbot's vertical overlay docs describe the same per-layer model we use at
scene granularity: "move or resize a layer on Vertical and it stops being
Auto-placed. It keeps the place you gave it, and the horizontal layout is not
touched" (bloopbot.com/docs/vertical-overlays-twitch-dual-format) - our
swap-at-tier-change, stored per scene.
- Landmine recorded: "about the bottom 560 px of the vertical video can be
covered by Twitch's chat and player controls on phones" (Bloopbot) - the Chat
camera's enlarged BOTTOM area may be half-hidden by the platform chrome;
TASK 53's safe-zone work decides that.
Memory in the same commit: ai.md (the Chat rules, the shape lock, the tests),
TASKS.md + TASKS/task-57-vertical-camera-layout.md (TASK 57 complete), HANDOFF.md,
MyMistakes.md (3 recipes: lock the model property not the UI button; two detents
for a discrete size set; the edit tool cannot match an oldString with an em
dash), Models/ViewModels/Controls index rows.
gramps
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