Remove unused `screen_delta_to_world` camera method (superseded by the
corrected pan_active_viewport formula).
Fix `is_content_viewport`: the old geometry fallback required the viewport
center to be near the origin, but DWG files never write the viewport id
field (stays 0) and the sheet viewport center is the paper centre
(e.g. 105, 148.5 mm for A4) — not the origin. This caused the sheet
viewport to be classified as a content viewport in DWG files, making it
both tessellated (border visible) and enterable via double-click.
The new heuristic uses only the scale: a sheet viewport has scale ≈ 1:1
(view_height ≈ paper height); true content viewports have deliberate
drawing scales (1:50, 1:100, …) that are far from 1.0.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
- Add `active_ucs: Option<Ucs>` per-tab state to DocumentTab
- Add `ucs_to_wcs`, `wcs_to_ucs`, `ucs_z_axis`, `ucs_rotated_z` helpers
- Add `Camera::pick_on_plane` for ray–plane intersection against any plane
- Mouse picks project onto the active UCS XY plane instead of world XY
- Typed coordinates are converted from UCS space to WCS before dispatch
- UCS command now really activates/deactivates a UCS:
- `UCS W` resets to WCS (clears active_ucs)
- `UCS <name>` activates a named UCS
- `UCS SAVE <name>` saves the current active UCS
- `UCS ORIGIN x,y,z` shifts origin (in current UCS space)
- `UCS X/Y/Z <angle>` rotates the UCS around its own axes
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
- Add active_viewport: Option<Handle> field to Scene
- Add EnterViewport(Handle) and ExitViewport messages
- Double-click on a user viewport (id > 1) enters MSPACE;
double-click on empty area while in MSPACE exits to PSPACE
- MSPACE middle-drag pans the viewport's model-space view (view_target)
- MSPACE scroll zooms the viewport's view_height / custom_scale
- Drawing commands inside MSPACE receive model-space coordinates
via paper_to_model() coordinate transform
- Active viewport rendered with yellow dashed border (vs. cyan solid)
- Camera screen_delta_to_world helper for MSPACE pan conversion
- LayoutSwitch clears active_viewport
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
