v0.11.0

The teksu! DSL reaches the code applications are actually made of: a call to
your own fn row(..) -> impl Widget is a child, where before only a stock
widget was. Alongside it the container API loses its twin methods, so a slot has
one name and that name takes a WidgetId or a widget.

Underneath, the GPU floor drops to what the renderer actually needs. A machine
with no Vulkan driver could not open a window at all; it now falls back to
OpenGL, which is what an older GPU has.

Added

teksu

• A lowercase identifier that continues into a call, a method chain or an index
  at body position is a child: VStack { my_row(x) } and
  VStack { row(1).spacing(4.0) } compile. A lowercase identifier standing
  alone is still the argument-free property.
• A keyword-rooted head is a child too: self.row(x), Self::header(),
  crate::ui::header(), super::row().
• #{ expr } carries a widget value as well as a WidgetId, which is how a
  Rust struct literal is passed at body position: #{ Card { title: t } }.

Widgets

• on_change on Checkbox, Toggle, RadioButton and Slider, taking the
  value the activation produced and an EventContext, so flipping one can send an intent, set the
  theme or open a window — things a bare Signal write cannot do, because an
  observer receives only &T. They fire for the pointer, for Space, for an
  assistive-technology Click, and, for a checkbox inside a data-view row, for
  Space on that row. They do not fire for programmatic writes to the bound
  signal: there is no event in flight to carry, and the signal remains the
  source of truth. A tristate checkbox reports a bool too, since activation
  cycles Checked ↔ Unchecked only. RadioButton reports only a real change,
  so re-activating the selected button is silent. Slider reports every value a
  drag produces, but not a write that changes nothing (a drag past the end, a
  snap onto the grid point already held); it has no commit-on-release callback,
  so once-per-interaction work still belongs on the signal.
• StandardListItem::on_checkbox_toggle and the StandardTreeItem forwarder,
  which make the embedded checkbox's on_change reachable — the canonical row
  builds its own checkbox, so it was the one place the callback could not be
  installed. To read check state, CheckedModel remains the answer: it is the
  source of truth and it survives row recycling, which a per-row callback does
  not.
• child_opt on every container that has child, 38 of them, up from 7. A
  bare teksu! if now works inside a single-child wrapper, not only inside a
  stack.
• 45 accumulator builders gained the plural twin that a for loop needs:
  tabs, static_tabs, panes, items, actions, lines, rails,
  docks, radios, full_width_rows, add_children and others.

Core

• Behaviour change. The row-activation marker a widget publishes with
  BuildContext::set_keyboard_toggle, and the fallback passed to
  EventContext::row_space_activate, are now Rc<dyn Fn(&mut EventContext)>
  rather than Rc<dyn Fn()>. Space on a data view's focused row therefore
  runs with a context, which is what lets a row checkbox fire on_change on
  that path instead of only under the pointer.
• Box<W> implements Widget for any W: Widget + ?Sized, so a boxed widget
  goes wherever a widget goes and adds no arena node.
• HandlerSet::merge_under composes two handler sets, the later declaration
  winning.

Documentation

• The teksu! reference leads with the real widget catalog: worked examples for
  ListView, TreeView, TableView, TabWidget, FormLayout, MenuList,
  Toolbar, Switcher and DockingLayout, and a section listing only what
  genuinely does not work, with the compiler's own text.
• The spec gains a Why there is no v4 section: what the DSL was measured to
  cost, the four charges against it that measurement did not support, the three
  silent-wrong-program bugs and the one grammar rule that did stand, and the two
  exits that stay available if the question reopens. It replaces the standalone
  decision note, which is removed.
• The binding trap is written down in both documents: binding names are one flat
  namespace per block, so two bindings sharing a name alias, both attach sites
  resolving to the later widget while the earlier one is built and attached
  nowhere.
• A root NOTICE file records what the theme presets derive from and on what
  terms: the WinUI theme-resource values under Microsoft's MIT licence, the
  Material 3 baseline tokens from documentation Google publishes under CC-BY-4.0,
  the macOS preset's mix of published and measured numbers, and every bundled
  font with its licence, its copyright line, and whether it is embedded by
  default.
• The trademark policy gains a Third-party trademarks section: it names the
  owners of macOS, Fluent, Material Design and Int UI, states that Teksilo is
  neither affiliated with nor endorsed by any of them, and separates the
  fluent theme preset from Project Fluent, the unrelated localization system
  behind Teksilo's translations.
• The two bundled-font license files are corrected. roboto-LICENSE.txt carried
  a summary of Apache-2.0 -- four of its nine clauses, paraphrased, with the
  redistribution conditions collapsed to one line -- where section 4(a) requires
  a copy; it now carries the complete text. noto-LICENSE.txt named one project
  and one year for two faces; it now carries the copyright line each font's own
  name table declares, notofonts/arabic 2022 and notofonts/hebrew 2024.

Changed

• CI runs cargo teksilo-fmt --check over crates and examples.
• FormLayout::lines takes impl IntoTeksiChild in both columns; the field
  column used to require impl Widget, so a loop holding ids could not use it.
• teksu-language-spec-v3.md is the design rationale and names
  teksu-macro-reference.md normative for behaviour; fourteen divergences from
  the implementation are corrected, and appendices A.2, A.3, A.4 and A.6 are
  marked superseded where they describe an API that has since been removed.

Removed

Behaviour change, breaking.

• StandardTreeItem::on_toggle / on_toggle_rc are renamed
  on_chevron_toggle / on_chevron_toggle_rc. They are the expand / collapse
  control, and the name became ambiguous the moment a row gained
  on_checkbox_toggle.

• add_child, child_id, child_boxed and every *_id slot twin, 80 methods.
  Call the slot by its own name instead: .child(id), .content(id),
  .header(id), .pane(id). Every widget-accepting slot method takes
  impl IntoTeksiChild, which is implemented for WidgetId and for every
  Widget. Not affected: shortcut_id, static_tab_with_id, the alternate
  constructors (from_id, new_id, around_id, custom_id,
  with_child_id), and Breadcrumb::item_id.

• WidgetBuilder::dim_when_inactive and dim_when_inactive_default. Wrap
  instead: DimWhenInactive::new().factor(f).child(w).

• Checkbox::labels_hidden(bool) is now Checkbox::labelled_externally(), the
  name and shape Toggle already used for the same thing: the control's
  accessible name comes from an ancestor, so it renders no label of its own.

• FormLayout::line_ids no longer adds one row from two ids; it takes an
  iterator of (label_id, field_id) pairs and adds a row per pair. The
  single-row form is gone because line takes impl IntoTeksiChild and accepts
  a WidgetId directly.

Fixed

Platform

• Teksilo opens a window on a machine with no Vulkan driver. OpenGL is the
  only backend such a machine has left — an older GPU, a VM whose guest driver
  stops at GL — and it was never handed the platform's display connection, so it
  could render offscreen but never present to a window. Startup died before the
  first frame with incompatible_surface_backends: GL. Confirmed fixed on both
  Wayland and X11 with the Vulkan driver removed.
• Adapter selection is a search rather than a single request. An adapter that
  enumerates but cannot open a device no longer ends the process, and an
  explicit software fallback is tried before giving up — the resilience the
  offscreen test device already had, and the window path did not.
• wgpu's own environment variables take effect: WGPU_BACKEND,
  WGPU_POWER_PREF and the rest were silently ignored, leaving no way to move
  off a backend whose driver is the problem.
• The remaining "no GPU" failure names the backends tried, the errors each gave,
  and what to install, in place of a Debug-printed wgpu struct.

Rendering

• Neither atlas asks for a texture the device cannot allocate. Both grow toward
  a 4096-pixel ceiling that is this renderer's own, not a fact about the
  hardware, and a downlevel device can sit below it; the path atlas now caps its
  growth to what the device reports, and a glyph atlas that arrives oversized is
  skipped rather than failing the frame.

Core

• Behaviour change. A builder method with no inherent twin on
  WidgetWithHandlers wrapped an already-wrapped widget, and only the outer
  handler set reached the node, so .on_tap(cb).clips_children_on(true) never
  fired. Handler sets at any depth now arrive.
• Chaining past dim_when_inactive retargeted the rest of the chain at the
  wrapper, so VStack::new().dim_when_inactive(0.7).child(a).child(b) built
  DimWhenInactive > b and lost the stack and a. The method is gone;
  teksilo-teksu-guard fails the build if a WidgetBuilder method returns a
  foreign wrapper again.
• ArrowLeft reaches a text editor again when a second one is mounted beside
  it. The dispatch root reads the inline-start arrow as "back toward the
  parent overlay" once two or more non-host overlays are stacked, and it counted
  every band alike. Each mounted RichTextEditor keeps one full-viewport
  affordance host in the TextAffordance band for its selection handles, so two
  editors on one page — a prose column and the synopsis next to it — read as a
  submenu over its parent menu: the key tore down an affordance host and
  returned, and no editor in that window saw an ArrowLeft for as long as both
  were up. The count now considers OverlayBand::Standard overlays only, the
  same line OverlayBand::dismissed_by_outside_press already draws for presses.
  A submenu over a mounted affordance still closes on the back key.

teksu

• teksilo-fmt re-indented a multi-line expression child by the block's own
  indent on every run, walking a multi-line argument list further right each
  time.

Full Changelog: v0.10.0...v0.11.0