feat: scroll viewports with mouse wheel without moving the caret

2026-10-10 01:23:16 +02:00
parent 455108a909
commit d8e2425c65
5 changed files with 1569 additions and 105 deletions
@@ -24,6 +24,7 @@ One crate; no workspace or terminal-coordinate types in the editing backend:

 Frontends drive `EditorSession::handle` or `execute`, periodically call `poll()` even without input, and inspect `editor()`; there is no mutable editor getter that could independently alter plugin registration. `poll()` reports whether background activity requires redrawing. Pasted text uses `Input::Paste(String)` through the same input seam as keys. Plugin effects are applied internally so a rejected result also retires its owner; there is no generic frontend effects entry point.
 Frontends inspect `selections()` for document-ordered, end-exclusive Visual ranges of grapheme coordinates (empty outside Visual), `carets()` for all active cursors in document order, `cursor()` for the primary, and `selection_count()` for the total target count. A range ending at the next row's column 0 includes the previous row's newline; an empty final-row range contains no text. Selection normalization, clipboard contents, edit planning, and history remain inside the editor module.
+The TUI also observes the editor's logical caret-reveal generation. Core motion/navigation dispatch advances it even when the resulting position is unchanged, so a detached viewport can resume following without duplicating key-binding policy or changing text revisions and LSP freshness.
 Frontends inspect `palette()` for the optional read-only query, filtered command entries, selected index, effective bindings, and eligibility. Palette input handling and acceptance stay in the editor; registered command execution stays in the session.
 Frontends use cached `selection_navigation_hint()` for command lists and `file_navigation_hint()` for the active file view/context, without reconstructing input policy.
 Frontends inspect `count()` for the optional pending motion prefix; parsing and counted motion dispatch remain editor-owned.
@@ -38,12 +39,14 @@ Frontends inspect `hover()` for optional read-only content and logical-line/grap

 ## Terminal lifecycle and layout

-The terminal adapter owns raw mode, alternate-screen state, bracketed paste, and its panic hook for one session lifetime. Entry failure, normal return, I/O errors, and unwinding panics restore the caller's hook; active-terminal cleanup runs before caller panic diagnostics. Panics retain their original payload and propagate rather than being swallowed. Terminal state and panic hooks are process-global: run one TUI at a time and do not replace its hook while that session is active.
+The terminal adapter owns raw mode, alternate-screen state, bracketed paste, mouse capture, and its panic hook for one session lifetime. Entry failure, normal return, I/O errors, and unwinding panics restore the caller's hook; active-terminal cleanup runs before caller panic diagnostics. Panics retain their original payload and propagate rather than being swallowed. Terminal state and panic hooks are process-global: run one TUI at a time and do not replace its hook while that session is active.

 Redraws bracket Ratatui's buffer diff and final cursor placement with DEC synchronized updates (mode 2026), presenting complete frames on supporting terminals rather than exposing intermediate rows. The hardware cursor is hidden before painting even when that extension is unsupported. Each frame releases synchronization; terminal cleanup also releases it before leaving the alternate screen or invoking caller panic diagnostics.

 The TUI uses Ratatui constraint-based layout for a flexible buffer viewport, a one-row status bar, and a one-row prompt/message area. Scrolling, clipping, highlights, and cursor placement use the allocated regions, not terminal-wide offsets. Below three rows the status bar is hidden; at one row the buffer remains visible unless an active command/search prompt takes priority. Zero-sized terminals render nothing. Layout and terminal-cell text mapping remain frontend-owned.

+Mouse wheel input uses the last rendered document/panel rectangles for hit-testing. Document offsets and explorer scroll state remain frontend-owned; three-row wheel steps never become document cursor motions. Manual document views persist until logical caret-reveal, caret/selection, mode, revision, or buffer changes; offscreen primary and browsing-selection cursors are not placed. Hover wheel input reuses the existing editor-owned popup scrolling.
+
 Ratatui's bounded layout cache is enabled: unchanged geometry and constraints reuse solved rectangles during scrolling; resizes and panel-layout changes use their own cache keys.

 The buffer viewport includes a fixed left gutter with right-aligned hybrid line numbers: the highlighted primary cursor line shows its one-based absolute number; every other line shows its distance from the primary. Secondary carets do not establish separate numbering origins. Gutter width follows the total line count plus one separator cell, including an empty final row after a trailing newline. Horizontal scrolling affects only text; search/selection highlights and carets never paint over the gutter. Rows beyond the buffer have no number. The gutter is hidden when it would leave no text column.