The dock grows on wide screens (task 7.3)

Operator design answer, 2026-10-14: “More slots when wide” — the dock grows past 4 slots on wide screens, and the extra slots stay empty until apps are pinned.

Rule

home_grid::dock_slots(width, height): one slot per grid column, but no more than the icon budget leaves after one full page (icon.rs CACHE_LIMIT = 24, so a full page plus its dock stays resident), and never fewer than the panel’s 4.

HomeLayout::fit_dock sizes the stored dock when the surface changes. Wider surfaces add empty slots at the end. Narrower ones never hide a pinned item: an item past the new end moves into the first empty slot that remains, or onto the grid when the dock is full.

Host evidence (host render, 2026-10-16)

home-1280x800.png and home-1232x568.png come from cargo run --offline --example render_responsive_evidence -- <dir>, which fills the dock with synthetic apps. Each shows six dock slots. The portrait home-568x1232.png from the same run is byte-identical to docs/evidence/shell-responsive/home-568x1232.png.

cargo test --offline --manifest-path nix/rust-shell-client/Cargo.toml --no-fail-fast passed: 547 lib tests (2 ignored) plus every integration target, 0 failures. The new tests are:

• home_grid::a_wide_dock_grows_within_the_icon_budget: slot counts, no overlap, inside the surface, and a centre tap hits each slot.
• home_state::fit_dock_grows_empty_and_shrinks_without_hiding_an_item.

The older wide Home renders under shell-responsive/, hdmi-hotplug/landscape/host-renders/ and panel-landscape/host/ record the 4-slot dock as it was before this change, and are left as history.

On the board (2026-10-16, ~00:44–00:48 CDT)

Evidence class: injected pointer events plus native grim captures. No real glass and no camera. Build 3f6eca48 (.#kernelMainlineDrmShellLandscapeHdmiBootFiles), system zqy2i8w0h672f69jw7843w1l0mqz4wv5, deployed live with switch-to-configuration test and the boot profile set. HDMI-A-1 at 1280x800. Pointer input is tools/board-pointer.py, a uinput mouse.

1. board-six-slots-1280x800-grim.png: after the deploy, Home’s dock shows six slots. The user’s four pinned apps fill slots 1–4, and slots 5–6 are empty, as the operator asked.
2. A long press on the Video app in the grid, then a drag to the sixth slot (hold 640 190 900, 12 moves to 1162,720, up). The shell logged home-layout-changed. The saved home.json dock then read [foot, Nautilus, editor, htop, null, k230-video]: six entries, persisted. board-video-dropped-in-slot-6-1280x800-grim.png shows the result while still in rearrange mode.
3. click 1194 80 (Done), then click 1162 720 on the sixth slot. The shell logged app-launch-requested and app-launch-mapped, so the new slot’s hit area launches its app. board-video-in-slot-6-1280x800-grim.png shows Home with Video in slot 6, out of rearrange mode, before the launch.
4. Cleanup: the Video window was closed, and Video was dragged back to its grid cell. home.json again matches the operator’s layout (Video in grid slot 4, slots 5–6 empty).

Limits:

• Shrinking the dock (unplugging HDMI back to the portrait panel) with an item in slot 5 or 6 was not exercised on the board; it is covered only by fit_dock_grows_empty_and_shrinks_without_hiding_an_item.
• The 1232x568 landscape panel dock is host-render evidence only.
• The first drag-back attempt did not take: the press landed in rearrange mode without a drag. A second attempt with a 1.2 s hold worked.