DensityToggle CLAUDE.md

Density Toggle - Wear OS display density control

Context file for Claude Code. Read this before changing anything.

Goal

A Galaxy Watch Ultra (480x480 round, Wear OS / One UI Watch) runs sideloaded phone APKs - YouTube, Uber, Bitwarden, Proton - whose layouts are built for a large rectangular screen. At stock density their UI overflows the round display and controls fall outside the visible circle.

The app lowers system display density so those layouts fit, and puts it back afterwards. Auto-first since v5.9:

• Auto - an accessibility service that shrinks when a chosen app comes to the foreground and restores when it leaves. Each chosen app can have its own density (default from the main screen, per-app override in the picker) and its own full-size-typing setting (per-app chip in the picker; no global toggle anymore).
• "Full-size typing" was removed in v5.15 after empirical retesting: the current One UI Watch keyboard works fine at low densities (its numbers/symbols gesture functions at 140), so lifting density while the keyboard was up no longer bought anything and cost a chip + a state machine. If keyboard breakage at low dpi ever returns, the git history has the whole implementation (kbPause/kbPaused/kbLiftFor + KB_SAFE_DPI=190) - re-test on the device before resurrecting it.
• Reach (v5.12, optional, off by default): corner controls of phone layouts are physically outside the round panel at every density - overscan was removed in Android 11 and One UI Watch's WM coerces freeform back to fullscreen (both verified on-device), so proxy-clicking is the ONLY workaround. The service shows a TYPE_ACCESSIBILITY_OVERLAY chip while a watched app is shrunk; the panel lists clickable nodes whose centre lies outside the inscribed circle and fires ACTION_CLICK on the chosen one. Overlay sizes are PHYSICAL px, never dp - dp shrinks with the density override, exactly when the chip is needed. Useless for unreadable trees (YouTube, invariant 10).
• The manual shrink workflow was removed in v5.9. The only manual control is a Restore to stock pill that appears while the screen is actually shrunk - the on-watch escape hatch. Do not remove it: without it a stuck shrink needs adb. (v6.0 briefly made it always-visible as "Reset to default"; reverted - it caused layout churn.)
• Rotation is NOT an in-app feature (v5.10 tried, v5.10.1 removed it - learn from this): shrinking density makes phone apps use tablet layouts, which honour SENSOR orientation, so apps rotate with the wrist. The accelerometer_rotation setting cannot stop sensor-orientation requests, so an in-app toggle built on it LOOKS like it works but doesn't. The mode that works - cmd window fixed-to-user-rotation enabled - is gated by a signature permission the app can never hold, is adb-only, and is persisted by the system across reboots. It lives in install.sh (--lock-rotation) and INSTALL.md. Do not re-add a rotation toggle to the app.