Canvas, screens, and layers
Hierarchy
Canvas (pixel size, test pattern flag)
├── Screen / VideoOutputDevice (window on a monitor, region on canvas)
└── Target layers (rect, name, lock) — draw targets for video/text

Canvas
- Default size 1920×1080.
- Test pattern draws a full-canvas alignment grid; each screen shows its intersection so multi-projector edges can be aligned.
Screens
Each screen corresponds to an output window managed by the displays system. Position the screen rectangle on the canvas to choose which stage region that window shows.
Layers
| Property | Role |
|---|---|
| Id | Target for components and OSC /Layer/{id}/… |
| Name | Operator label |
| Position / size | Geometry on the canvas |
| Locked | Blocks interactive and OSC moves |
Control components can translate layer geometry over time. OSC can set pos/size when unlocked.
