The GlyphLayout is shaped from the visible window alone, so its
ByteOffsets are relative to the window start (IMEWindowStartByte). But
SetCursorFromPoint, HandleHome, HandleEnd and HandleVerticalCursorMove
treated them as absolute file offsets. On a large file scrolled deep, the
cursor was set to a window-relative offset (near the file start), so the
next EditorLayout computed visibleCursorPos = CursorPosition - start as a
small/negative value and the IME selection snapped to the window top
(regardless of where the user tapped).
Add glyphBase() and convert at the four cursor boundaries: subtract the
base before searching the window-relative offsets, add it back before
storing the absolute CursorPosition. For small files (window == whole
file) the base is 0 and the change is a no-op.
Add TestTapToPosition_WindowBaseOffset, a regression test that sets a
non-zero IMEWindowStartByte and asserts the cursor lands at base + window
byte (fails on the pre-fix window-relative assignment).
Verified on-device: with a 6 MB file scrolled to ~line 1200, a tap now
places the cursor on the tapped line (typed text lands ~16 lines below the
window top), where before it always landed on the window top.
Tapping in the editor repositions the cursor, but it was never actually
verified (the old unit test only checked in-bounds/no-panic). On-device
verification found that on a large file scrolled deep, the cursor clamped to
the bottom of the viewport regardless of tap position.
Root cause: the tap handler computed the tap's text-local Y in content space
(pt.Y - region.Y + full ScrollOffset) and passed it to SetCursorFromPoint,
whose visualLine = y/lineHeight then produced a huge content-line number
(e.g. 91,640). But the GlyphLayout is window-relative (layout.Y==0 is the top
of the visible window), so the number far exceeded the window's line count and
clamped to the last group (bottom line). The Phase 3 windowing refactor
introduced the windowed layout without updating the tap handler.
Fix: tapLocalY() converts the tap Y to window-relative space by adding only the
sub-line remainder (ScrollOffset mod lineHeight), never the full scroll.
Extracted as a named helper so it is unit-testable. Added two regression tests
that fail on the pre-fix formula (cursor clamps to the bottom line) and pass on
the fix. Verified on-device: taps now map linearly across the viewport.
Also removed the per-tap/per-glyph log.Printf debug lines in SetCursorFromPoint.
- Rewrite cursor_test.go to use the current GlyphLayout-based API
instead of the deleted byteOffsetToLineCol function
- Add guard for empty/missing layout slices in SetCursorFromPoint
to prevent index-out-of-range panic on empty documents
- Add missing Advance field to e2e test GlyphLayout initialization
- Add cmd/pad/pad binary to .gitignore
- Replace gtx.Event(nil) with key.Filter{Focus: focusedID} and
key.FocusFilter{Target: focusedID} so Gio correctly routes key
and edit events to the focused editor text field.
- Convert EditorState.CursorPosition (byte offset) to line/column
coordinates for accurate cursor rendering.
- Add debug logging in HandleKeyDown and HandleCursorMove.
