User guide / Terminals

Emulation and limits

Development reference · View source

The emulator is Runyte’s own, like the fuzzy scorer, the picker, and the diff.

Supported: colour including the 256-colour palette and true colour, the usual attributes, scroll regions, insert and delete, the alternate screen, bracketed paste, application cursor keys, cursor-position reports, and window titles.

Scrollback and performance:

  • Scrollback is bounded at 5,000 lines per session and by a measured 64 MiB retained-cell and review budget per workspace.
  • Noisy sessions use independent bounded queues and round-robin byte and message budgets. PTY input is bounded and chunked.
  • Terminal and review output is never written to disk.
  • Output frames are coalesced to a bounded cadence. Repainting sends only changed rows, with a full resynchronization when the base is stale.
  • Rapid identical wheel reports are merged into bounded requests, keeping their scroll distance and their order relative to clicks and keys.
  • The alternate screen has no history, so while htop or vim runs there is nothing behind the screen to scroll to or copy.
  • Inline TUIs on the primary screen may keep a composer or status area fixed while completed output scrolls through a top-anchored region. Those completed rows are ordinary scrollback, including Codex output in inline mode.

Mouse. SGR mouse reports are forwarded inside the pane body when the child asks for them. Borders stay Runyte’s, and the wheel scrolls review history when the child has not asked for the pointer.

Colour queries. Read-only OSC 10;? and OSC 11;? queries get the theme’s default foreground and background, so light- and dark-aware programs pick fitting colours. A theme colour set to reset is unknown and gets no reply. OSC 4 palette queries and setters remain ignored even with theme ANSI colours enabled: colour depth and palette rendering belong to each attached client.

Known limitations:

  • Colour-setting and palette queries are ignored, as is OSC 52, so a program cannot change the palette or write your clipboard unasked.
  • A cell keeps up to three combining marks without taking columns; more are deliberately dropped.
  • Inline images — kitty graphics, sixel — are not passed through.
  • Resizing does not reflow wrapped lines. Emulators disagree about what a resized wrapped line should become, and a wrong guess corrupts a live full-screen program worse than truncation does.
  • Windows provides ide-mode and mux-mode ConPTY terminals.