Subsurfaces can now be parented to an overlay surface, not just the main surface. `SubsurfaceSpec` gains `parent: SubsurfaceParent { Main, Overlay(id) }` so a sliding panel can ride above app windows the way an overlay panel does, and an optional `gpu: bool` so content that uses the `surface-panel` backdrop-filter glass (a GLES-only pass) keeps it while sliding instead of dropping to the software rasteriser. `reconcile_subsurfaces` resolves each spec's parent independently — skipping an `Overlay` parent that is absent, unconfigured, or zero-sized — tracks the rastered size on the slot, and commits each touched parent once per frame. The ~14 GLES shader programs are compiled once into a shared `AppData::subsurface_gles_canvas` reused across every subsurface, so a lazily re-created sliding panel never recompiles them (hundreds of ms on a mobile GPU).
Vertical and horizontal swipes are now mutually exclusive: a gesture locks onto its dominant axis within the first 8 px of travel (new `SwipeAxis`) and ignores the perpendicular axis for the rest of the gesture, so a vertical swipe that drifts sideways no longer also drives the pager (and vice-versa). The upward swipe progress is no longer clamped at 1.0 — follow-the-finger panels can keep tracking the finger past the commit threshold — and a release below threshold delivers a final `progress = 0.0` cancellation pulse. A vertical swipe also no longer re-rasters the full-screen main surface on every motion event: only the overlays it drives are refreshed, while the horizontal pager (which does move the main surface) still redraws it. Re-rastering the main on every frame of a vertical drag was wasted work that stalled the loop and made the gesture feel laggy to start on a slow GPU.
Layout-affecting `Length` values (widths, paddings, gaps, widget sizes, including `Vw` / `Vh`) now resolve against the physical viewport via the new `Canvas::viewport_layout()` — the space the layout tree is actually computed in — so a `Vw(100)` fills the surface on a HiDPI (scale 2) output instead of covering half of it. Font sizes are unchanged: they still resolve against the logical viewport and are scaled at raster time. Switched column, row, spacer, wrap_grid, container, image, and vslider over to it; `img_widget` and `vslider` now document `Length::vw` / `vh` sizing and the showcase example demonstrates a viewport-relative image.
Touch gesture state is reset when the touch capability is added or removed — suspend / resume on devices that power the touchscreen down. A yanked capability never delivers the pending `up` / `cancel`, so the shared `reset_touch_state()` (also used by the `wl_touch.cancel` handler) drops the stranded `primary_touch_id` / slot state across the main surface and every overlay, keeping the first post-resume gesture clean. Also drops an accidental duplicate `on_scale_changed` call from the scale-change handler.
Forge's app switcher needs two layouts the existing widget set didn't cover. The desktop grid wants a partial last row centred under the rows above (3 tiles → row 1: two, row 2: one centred) so a 7-of-9 leftover band reads balanced rather than left-aligned. The mobile variant wants a horizontal carousel where the focused tile sits centred in the viewport at a configurable fraction of its width and its neighbours peek out on the sides at a fixed gap.
Extend `WrapGrid` with `centre_last_row( bool )`. When set, layout offsets a row that has fewer than `columns` children by `(missing * (cell_w + spacing)) / 2` so it stays centred inside the content rect. Defaults to false; every existing call site continues to land tiles flush-left. Covered by three layout tests (centred partial row, full row no-op, off-by-default).
Add the `Carousel` widget at `src/widget/carousel/`. It is a pure layout primitive: `focused_width_frac` (0.05–1.0, clamped), `gap` and `offset` are owned by the caller, leaving drag / inertia / snap policy to the host so the compositor can plug in its existing touch pipeline. Each child gets a rect at `base_x + idx * (child_w + gap)` and the full viewport height; `snap_offset( viewport_w, idx )` translates index to centring offset and `focused_index( viewport_w )` rounds the current offset back to the nearest tile. Plumbed into `Element::Carousel` with the matching arms in `widget/element.rs` and walker in `draw/layout.rs`; re-exported as `ltk::{ Carousel, carousel }`. Covered by nine unit tests (layout, offset shift, snap / focus round-trip, frac clamp, child height) plus a `cargo run --example carousel` demo with Prev / Next / arrow-key navigation against an external offset state. The example is wired into the `examples` Makefile target.
Updates the widget catalogue and the `widget/mod.rs` landing comment to list the carousel under "Clipping wrappers" and to mention `centre_last_row` in the grid section.
`Button::tooltip( text )` registers a hint string that fires after a 600 ms pointer dwell. `LaidOutWidget` gains a `tooltip: Option<String>` field, `Element::tooltip()` exposes it to the input layer, and the existing pointer-hover path now calls `arm_tooltip` on hover-enter and `cancel_tooltip` on hover-leave / touch. The deadline is polled alongside `next_long_press_wakeup` in `try_run` so an idle pointer still gets a wake-up at the firing instant; on fire, `tooltip_overlay()` synthesises an `OverlaySpec` — a rounded `text_primary @ 95%` pill drawn with `bg` text — anchored above the hovered widget, flipping below or clamping inside the screen if it would clip, and pushed alongside the app's own overlays both in the redraw path and in `reconcile_overlays` so the layer surface is created the same frame the tooltip becomes visible. Pointer-only by design: touch events explicitly cancel because a tap-and-release should never linger into a hint. The `showcase` example wires `.tooltip(..)` on the three button variants as a smoke test.
The drag pipeline now reports positions in main-surface (global) coordinates instead of per-surface. `surface_offset_for( focus )` derives the top-left of an overlay surface from `SurfaceState::layer_anchor` — newly stored at `reconcile_overlays` time from `OverlaySpec::anchor` — combined with the main surface's dimensions; `on_drag_move`, `on_drop`, the synthetic move emitted on drag-promotion in `pointer.rs`, and the `pending_drag_inits` push site in `gesture::start_drag` all translate before handing coordinates to the app. The motion and release paths additionally `request_redraw()` every overlay so a dock-style drop target painted on an `Anchor::Bottom` layer surface gets repainted as the drag moves — without that, the visible drop indicator only updates when the cursor re-enters the main surface. Drops still target whichever surface fired the release; only the coordinates are unified.
`ForeignToplevelListHandler` previously read `app_id` directly via `ForeignToplevelList::info()`. Clients that never set `app_id` (some winit-windowed compositors, simple test clients) were silently invisible to crustace-style docks because the empty string fell through `unwrap_or_default()` and the dock then keyed entries off `""`. `toplevel_display_id()` cascades: prefer `app_id` for desktop-entry matching, fall back to `title` for human-readable identification, and finally to the protocol-issued `identifier` which is always present and unique per handle. Applied to both `new_toplevel` and `update_toplevel`.
`theme::system_fontdb()` lazily loads the system font database once via `OnceLock` and reuses the `Arc` for every `decode_svg_bytes` call. resvg's default `Options::fontdb` is empty, so any SVG containing `<text>` rendered with the built-in fallback font or no font at all; with the system DB attached, icons and decorative SVGs with embedded labels now resolve glyphs correctly. Cached because `load_system_fonts()` walks every font path on the system and is comfortably tens of milliseconds on a cold cache — not something to repeat per icon decode.
`themes/default/theme.json` tweaks one variant's slot palette: `surface-alt` from `@indigo/D9` to `@white/D9` and `text-primary` from `@white` to `@navy`, plus a cosmetic re-alignment of the `"value"` columns in the same slots block.
