Introduce editable text layers: a resizable text box with editable text,
font size, color, font family, and alignment.
Core:
- New TextLayer/TextContent (text_layer.rs), wired into AnyLayer/LayerType
and all the exhaustive match sites; structured so content can be keyframed
later via content_at().
- fonts.rs: thread-local parley FontContext with three bundled fonts
(Liberation Sans/Serif/Mono, SIL OFL), system-font enumeration consolidated
to base families, document-embedded fonts, glyph/caret/selection geometry,
and a background preloader for the picker fonts.
- Rendering via parley layout + Scene::draw_glyphs (renderer.rs); text
composites through the vector path.
- Actions: CreateTextClipAction (vector-layer branch, undoable),
SetTextContentAction, ResizeTextBoxAction.
- .beam font embedding: MediaKind::Font rows (content-hash dedupe) written on
save and registered on load, with bundled-default fallback.
- VectorClip content bounds include text boxes so text-only clips are
selectable/draggable.
Editor:
- Text tool: click empty/raster/video to create a top-level text layer, or a
vector layer to create+enter a clip containing the text; click an existing
box to edit it.
- Hybrid in-place editing: a hidden egui TextEdit drives input/IME/caret while
the text and caret/selection render in Vello; empty just-created layers are
removed on commit.
- Selection outline + 8 resize handles (re-wrap text) with hover cursors;
factored the corner/edge resize-cursor mapping shared with the Transform tool.
- Info panel: edit text, size, color, alignment, box size, and a font-family
picker that previews each entry in its own font (fonts preloaded in the
background to avoid hitches).
Deps: add parley (git, pinned to match vello's peniko); bundle Liberation
fonts under lightningbeam-core/assets/fonts. Gitignore the local
.cargo/config.toml used to select a machine's ffmpeg.