irisandClaude Fable 5
9477cd288a
Opening the keyboard was late on 82% of frames on the Pixel while the transcript itself cost 0.25ms of each -- the cost was everywhere else. imePadding() sat on the activity's root box, so every frame of the IME animation resized the entire tree: measured on the emulator (with the new app-root timers) as a full re-measure (4.1ms), re-place (2.5ms) and re-record (1.0ms) of everything, ~34 frames per open, while the newly added recomposition counters read zero -- pure layout traversal, no recomposition to fix. So the keyboard now touches only what actually moves. The session screen's composer (status row, suggestions, attachments, text field, buttons) is a bottom-aligned overlay on its own layer, translated by the IME inset read inside the graphicsLayer block -- a keyboard frame invalidates layer properties only. The transcript box reserves the overlay's measured height plus imePadding, and that modifier is the whole of what the keyboard re-measures: the box's own size never changes, so the header and everything above it are untouched. The overlay is opaque for the one frame between it growing and the reservation catching up. imePadding moved off the activity root onto AppRoot's other screens, which keep the old arrangement -- none of them has a keyboard open over anything that scrolls at 120Hz. Same five-open protocol on the emulator, before and after: the app root is now measured zero times (was 168), per-frame app work 7.6ms -> 1.9ms (transcript measure 1.2 + place 0.5 + record 0.2), draw-phase p90 9.6ms -> 5.0ms, waited p50 2.6ms -> 0.4ms. What is left per frame is the transcript's own one-box remeasure, whose children skip measurement because their width is unchanged. Verified the states the overlay could have broken: keyboard over a long and a two-message conversation (content hangs from the composer in both), a three-line draft growing the composer upward with the reserve following, slash suggestions stacking above the field, and the closed state identical to before. The app-root timers and the recomposition counters stay in: they are the difference between this report saying "draw is high" and saying where. Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>