On mobile the on-screen keyboard overlays the layout viewport instead of
resizing it (iOS Safari always; Android Chrome under its default
interactive-widget=resizes-visual). The dashboard shell is a fixed h-dvh
column, so the xterm host's bounding box never changed when the keyboard
opened: fit() computed identical (cols, rows), no RESIZE reached the PTY,
and the Ink input line — drawn at the bottom of the grid — stayed hidden
under the keyboard.
Fix, in three parts:
1. Keyboard-inset handling (new web/src/lib/keyboard-inset.ts).
computeKeyboardInset() measures the layout-viewport region obscured by
the keyboard via window.visualViewport
(innerHeight - vv.height - vv.offsetTop, with an 80px floor so
collapsing URL-bar chrome doesn't thrash the grid). ChatPage applies
it as bottom padding on the terminal wrapper, which shrinks the host →
the existing ResizeObserver/fit path recomputes rows and sends RESIZE →
Ink redraws the input line above the keyboard. Listens on both vv
resize and scroll (offsetTop changes arrive as scroll events on iOS).
2. interactive-widget=resizes-content in the viewport meta. Android
Chrome 108+ then resizes the layout viewport natively and the JS inset
computes ~0 (harmless no-op); iOS ignores the directive and takes the
JS path.
3. Scroll pinning. iOS auto-scrolls the page to reveal xterm's hidden
textarea on focus, which drags the fixed shell offscreen. While a
keyboard inset is active we pin window/scrollingElement scroll back to
0 and term.scrollToBottom() so the freshly-resized input line stays in
view.
Unit tests cover the inset math (thresholds, offsetTop, rotation races,
fractional geometry, non-finite guards). Grid-level behavior needs a real
device pass — DevTools emulation doesn't model keyboard insets.
Shannon Sands
67710548ec