v0.27.0

Typed widget DSL — ui! widget names are now first-class component constructors. Button (...) { Text("Click") } expands directly into the right world.insert(__w, Button { ... }) (and inserts a child Text node), no more enchant block boilerplate to wire up the actual widget kind. The whole gallery + esp32c3-animation moves over; lowercase widget names still parse for now (Layout fallback) but are slated for hard rejection in a follow-up.

Added

• Typed widget syntax — capitalised ui! names map to component types:
  • Built-ins: Button, Checkbox, Slider, Switch, ProgressBar, TabBar, TextInput, Image, Text, LazyList, MirrorOf, BackgroundBlur, TemporalMix.
  • Reserved layout names View / Row / Column stay as pure layout containers; Row / Column auto-set FlexDirection.
  • Anything else capitalised expands the same way and lets rustc check the type — user-defined components opt in by registering a View and (typically) impl'ing Default.
• Component widgets accept positional arg for a primary attr — Text("hello"), Image(&IMG_THUMBS_UP). Widgets without a registered primary attr reject positional args at compile time.
• Named niche slots — @name { children } inside a component widget routes children into a NicheMap-registered anchor entity. Components publish a NicheMap from their auto_attach; ui! resolves the anchor at fill time.
• id references — id: "foo" attr registers a NamedId marker on the entity and an entry in the new IdMap resource. id("foo") (or unquoted id(foo)) inside any other attr value expands to a World::find_by_id lookup hoisted to the surrounding scope, so a sibling can refer to a marked entity by name.
  • IdMap is auto-inserted by App::new, available everywhere; World::find_by_id(&'static str) -> Option<Entity> is the read API.
• match syntax — ui! { match expr { Pat => { children } ... } } inserts only the winning arm's children. Composable with niche / walk / if.
• Empty children blocks may be omitted — Image (texture: &IMG) (no {}) parses as a Widget with no children. if / walk / @niche / match still require their bodies.
• Multi-attr root header is multi-line and accepts trailing commas — :( parent: root, world: w, :) and the existing newline form both parse; mashing them onto a single line errors out at parse time.
• Off-screen renderer tests — new tests/typed_widget_visual.rs, tests/theme_swap_visual.rs, tests/typed_widget.rs, tests/niche.rs, tests/match_syntax.rs, plus gallery/examples/theme_swap_snapshot.rs for ad-hoc PPM/PNG dumps.
• trybuild fixtures for ui! diagnostics: unknown_attr_typo, id_must_be_string, root_header_oneline, positional_on_unsupported, button_no_text_attr.

Fixed

• App::render now wraps its full-screen flush in begin_flush / end_flush — previously the first frame after App::run only called Surface::flush, which on SDL leaves pending_present pinned without calling canvas.copy + canvas.present. Standalone SDL demos that didn't pull in InputFeedbackPlugin (which keeps the dirty path firing every frame) showed a black window until the user moused over a widget. The App::render_dirty non-empty branch had the right wrapper already; this brings the full-render path in line.
• Fuzzy hint for unknown ui! attrs — typing txt: now suggests text: via Levenshtein-2 lookup against the known attr list.

Changed

• Button no longer accepts text: attr — the label belongs in a child Text node now: Button (...) { Text("Click") }. The legacy text: writes the string into WidgetBuilder::text on Layout-kind widgets only; on Component widgets it routes to the struct's text field, which Button doesn't have, so the old form fails to compile with a clear error.
• Text is a tuple struct (Text(Vec<u8>)); the macro special-cases Text(text: "x") and Text("x") to emit Text(b"x".to_vec()) instead of named-struct init.
• TextInput's text_color / placeholder_color / cursor_color / focus_border_color route to the struct field, not the WidgetBuilder, when the widget is a TextInput.
• Slider and TabBar gain Default impls so the macro's ..Default::default() spread can fill in unset fields. Defaults are sentinels (Slider → (0..1), TabBar → count: 0); always overridden in practice by the call site.
• parse_attrs returns a ParsedAttrs struct rather than a tuple (avoids clippy type_complexity).

BREAKING

• Demos that wrote dark_btn (...) [Button::new()...] must rewrite to Button (...) [...] { Text("...") }. The codemod that ran during this development cycle handled the gallery + mirui-examples sweep; user code on the legacy syntax keeps compiling on the lowercase Layout fallback path until a later release tightens that.
• xrune's DsAttr.name becomes Option<syn::Ident> (positional args have name = None). Every DsRune impl gains inscribe_niche and inscribe_match. xrune workspace depends on xrune = "1.4" (see xrune CHANGELOG).
• mirui-macros Cargo.toml requires syn with visit-mut feature.