Scrollback & Copy

Scrolling

Cold-history packing runs in incremental maintenance turns, rather than encoding the entire backlog under one terminal lock. Each turn visits at most 512 rows and packs at most one block per grid, with a 128 KiB shallow-cell target (a single oversized row may exceed that target). This is a work bound, not a guaranteed wall-clock deadline. Visible and recently used history remain directly readable.

On Unix, the existing PTY actor services input and output between continuations. Windows uses bounded app-loop maintenance with a short deadline only while work remains; maintenance alone does not request a redraw. Reflow queues repacking, and new output invalidates an interrupted scan safely. Once the backlog is complete, no maintenance timer remains. Retention and copy semantics are unchanged.

Mouse/trackpad: just scroll over a pane. Apps that enable terminal mouse reporting receive their wheel input; full-screen apps that request alternate scrolling do too. Regular transcripts scroll Luvus’s retained history.

Each pane has a 10 MiB retained-history budget by default. Change it in Settings → Layout → Scrollback memory. Luvus’s Alacritty adapter converts this budget to a conservative row limit at the current pane width, so it protects memory predictably but reports retained bytes as an estimate rather than an exact allocator measurement. Reducing the setting trims existing history immediately; increasing it applies to subsequent output.

Completed rows stay fully lossless but cold history is packed into bounded, shared blocks. Repeated cells use a block-local dictionary, while high-entropy content falls back to direct packed cells. The visible screen and recent 128 history rows stay in the normal mutable representation. Unix schedules packing on a bounded activity deadline inside the existing PTY descriptor actor; Windows uses its coalesced output boundary. This adds no thread or idle polling, and reading old history does not inflate the complete transcript.

Keyboard scroll mode: press Shift+↑ (no prefix needed, so it works even where macOS eats Ctrl+Space). The status bar switches to SCROLL and plain keys navigate without reaching the program in the pane:

Key	Action
1–9	jump through history (1 = oldest, 9 = newest)
j / k (or ↓/↑)	line down / up
f / b (or Space/PageDn/PageUp)	page down / up
g / G	top of history / live bottom
q, Esc, 0, or just typing	back to live

While scrolled, a ↑N badge at the pane’s top-right shows how many lines up you are, and anything you type snaps back to live first, so you always see what you’re typing.

Unmodified PageUp and PageDown scroll normal transcript history. When a terminal app has claimed paging input (for example a full-screen TUI or an application-cursor pager), Luvus forwards those keys unchanged. Shift+↑, Shift+PageUp, and prefix scroll shortcuts remain explicit Luvus controls.

Copying

Drag across a pane to select. Release requests a copy and flashes a Copy requested toast. Luvus requests both your native OS clipboard (pbcopy / wl-copy / xclip / clip) and OSC 52. The terminal must permit OSC 52 clipboard writes; that escape sequence does not acknowledge whether the clipboard changed. Soft-wrapped display rows copy as one logical line. Hard line breaks and any leading indentation inside the selection remain unchanged.

Clipboard helpers run on the client machine, including when attached over SSH. On Linux, the client uses wl-copy when WAYLAND_DISPLAY is set and X11 helpers when DISPLAY is set. It preserves the client’s display environment, including XDG_RUNTIME_DIR and sockets named wayland-1; it does not use the remote server’s display or guess a socket name. Launch the client from your desktop terminal with those variables intact. Restarting the background server does not repair a missing client display environment.

Unix helper work runs off the rendering loop with a two-second timeout per helper. Failed helpers fall through to another applicable helper. Rapid copies retain only the latest pending selection. If all attempted helpers fail, Luvus requests a terminal notification explaining that native copy failed and OSC 52 was requested instead. Failure notifications are queued for the UI thread; an idle thin client shows them with the next server message. Notifications also depend on terminal support. When no native helper applies, OSC 52 remains available without a native-success claim. No clipboard text or helper stderr is logged.

For Wayland troubleshooting, run wl-copy and wl-paste from the same outer terminal that launches the Luvus client. Check WAYLAND_DISPLAY and XDG_RUNTIME_DIR there, not just in the detached server. A socket symlink is not required. Applications inside a pane can also copy with OSC 52 (for example Claude Code drag-select or printf with a \e]52;c;… sequence). Luvus forwards those writes through the same client clipboard path as its own selection copy. OSC 52 read (paste from the host clipboard into a pane) is not enabled. Rapid pane and selection copies retain only the latest pending text.

For keyboard selection, press Ctrl+Space, then y by default. Change the second key in Settings → Keys → Copy terminal text. Shift-based V input always passes through to the terminal, including inside agent prompts. Copy mode keeps all navigation inside Luvus. Its word motions are whitespace-delimited, so w and e behave like vim’s W and E:

Key	Action
arrows or h/j/k/l	character and line movement
w / e / B	next word start / word end / previous word start
Space or f / b	page down / up
Ctrl+D / Ctrl+U	half a page down / up
g / G	oldest / newest retained row
1–9 then a motion	repeat it, so 12j moves twelve rows
N then g or G	jump to retained row N, like vim’s NG
v	reset the selection anchor at the cursor
y or Enter	copy and return to live output
q or Esc	cancel and restore the viewport where copy mode began

A typed count shows in the status bar until a motion consumes it. 0 only joins a count already being typed — on its own it stays “first column”. Counts are capped at four digits, and any key copy mode does not recognise clears the pending count instead of reaching the program in the pane.