Paper limits:
- Change A4 fallback from 12×9 to 297×210 mm in paper_limits()
Context menu:
- Translate layout context menu labels to English (Rename / Delete)
Viewport clipping:
- Replace AABB-only culling with proper Cohen-Sutherland line clipping
in viewport_content_wires(); each projected segment is now clipped at
the exact viewport boundary instead of being included or discarded whole
- Add cs_clip() and clip_polyline_to_rect() free functions in scene/mod.rs
Frozen layers per-viewport UI:
- Inject a "Frozen Layers" EditText property in the Properties panel for
viewport entities (layer names resolved from handles at display time)
- Handle "frozen_layers" in PropGeomCommit: parse comma-separated names,
resolve to layer handles, update vp.frozen_layers in-place
PDF export improvements:
- Add offset_x/offset_y params to export_pdf() for model-space normalization:
coordinates are shifted so the drawing origin maps to the page origin
- Model space export computes extents via model_space_extents() (now public)
and adds a 5 % margin; falls back to A4 landscape for empty drawings
- Skip __paper_boundary__ wire in PDF (white background covers it)
- Map yellow (active viewport border) → black and cyan (vp border) → dark
blue for print-friendly output
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
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