Paper space is now rendered as a 2D vector canvas (iced::widget::canvas)
instead of a 3D shader widget. This allows direct interaction with
paper-space entities (title blocks, viewport borders, annotations)
without needing to enter MSPACE first.
Changes:
- src/scene/paper_canvas.rs: new PaperCanvas<'a> canvas::Program that
renders paper wires (with linetype dashes), solid/gradient hatch fills,
and wipeout backgrounds using the paper camera's orthographic transform.
- Scene: three new public helpers (paper_canvas_wires, paper_canvas_hatches,
paper_canvas_wipeouts) feed the canvas with the same data the old shader
used, including inactive viewport projections and interim/preview wires.
- view.rs: paper_canvas_view() now wraps PaperCanvas instead of
shader(ViewportPane::paper_sheet(…)). The PaperViewportPane 3D shader
overlay for the active MSPACE viewport is unchanged.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
