Struct PlainRenderer 

pub struct PlainRenderer<W: Write + Send> { /* private fields */ }

Plain-text renderer for pipes, CI, dumb terminals, and TUI-incompatible terminals (e.g. JetBrains JediTerm — see lib.rs JediTerm fallback). No raw-mode dependencies, no DECSTBM, no cursor positioning.

Plain mode does support a few low-effort UX wins on top of bare printf, all gated by TerminalCaps:

• Spinner via \r — overwrites the same line during streaming, so users see “in progress” feedback without animation tearing (cooked-mode \r always works; this is what read-with-progress scripts have used for decades).
• SGR colours — red errors, green/red ✓/✗, cyan tool-call names when caps.colors is on. Pure inline SGR; no positioning required.
• ❯ chevron — replaces > when caps.unicode_symbols is on, so the prompt visually matches the retained-mode chevron. Same two-cell width as > so layout math is unchanged.

Implementations

impl PlainRenderer<BufWriter<Stdout>>

pub fn new() -> Self

Convenience for the common “stdout + probe caps” path. Tests should use with_writer_and_caps so they can pin caps deterministically.

impl<W: Write + Send> PlainRenderer<W>

pub fn with_writer(out: W) -> Self

Backwards-compat constructor used by older test paths. Probes caps from the environment — fine for production, but tests that want predictable behaviour should use with_writer_and_caps or the explicit with_writer_caps_and_interactive.

pub fn with_writer_and_caps(out: W, caps: TerminalCaps) -> Self

Defaults interactive_terminal to caps.tty. Production callers in lib.rs use with_writer_caps_and_interactive instead because the force_plain branch needs to pass the PRE-mutation tty value (caps.tty has already been zeroed by then so the renderer would otherwise think it’s in pipe mode).

pub fn with_writer_caps_and_interactive( out: W, caps: TerminalCaps, interactive_terminal: bool, ) -> Self

Explicit constructor that decouples caps.tty from the echo-handling decision. Used by lib.rs to pass the original tty value alongside a force_plain-mutated caps.

Trait Implementations

impl Default for PlainRenderer<BufWriter<Stdout>>

fn default() -> Self

Returns the “default value” for a type.

impl<W: Write + Send> Renderer for PlainRenderer<W>

fn render(&mut self, line: UiLine)

Emit one UiLine. Implementations may batch internally; call flush() to force.

fn flush(&mut self)

fn shutdown(&mut self)

Shutdown: disable bracketed paste, disable raw mode, etc.

fn reset(&mut self)

Forget all cached rendering state (footer rows, last footer snapshot, assistant-text mid-line buffer, markdown parser) AND clear the physical terminal screen. Used by callers that hand control back to a non-TUI process (e.g. the blocking OAuth flow in /login) and then want a clean slate — without this, the next render tries to erase_footer at a position the terminal cursor is no longer at, corrupting every subsequent ANSI cursor move.

fn clear_screen(&mut self)

Wipe the physical terminal with \x1b[2J\x1b[H and flush. Does not touch cached footer/stream state — callers that want a full state wipe should call reset() instead. Use this when only the visible scrollback should be cleared (e.g. the /clear command after which the footer immediately redraws).

fn suspend_for_external(&mut self)

Hand the terminal off to a non-TUI child process (blocking OAuth flow, /shell, etc.): disable raw mode + bracketed paste, finish any pending writes. After this returns, the child is free to use the terminal in cooked mode; resume_from_external() must be called before any further render() calls.

fn resume_from_external(&mut self)

Take the terminal back after suspend_for_external(): re-enable raw mode + bracketed paste AND call reset() to wipe the cached state (the child wrote to stdout in cooked mode, so our cursor tracking is now lying).

fn flush_deferred(&mut self)

Paint any throttled payload that’s been sitting in the deferred queue past its throttle window. Called from the event loop on a ~50fps timer so the “trailing edge” of a burst of input renders actually lands — without this tick a lone stale payload would stay invisible until the next unrelated render arrived.

fn pop_approval_prompt(&mut self)

Remove the most recent ApprovalPrompt body row, if the tail row is one. Called by the event loop after the user responds Y/A/N so the prompt stops sitting in the body above the footer. Default: no-op — implementations that stream body lines to stdout (plain/pipe mode) can’t retract them.

fn on_resize(&mut self, _cols: u16, _rows: u16)

Terminal window was resized to (cols, rows). DECSTBM-based renderers must re-issue the scroll region (\x1b[1;H-N r) so the fixed footer stays pinned to the new bottom. Non-DECSTBM renderers can treat this as a redraw hint or a no-op.

fn scroll_body(&mut self, _delta: i32)

Scroll the body viewport up (negative delta) or down (positive delta) by delta rows. Used by AltScreenRenderer to support PageUp / PageDown / arrow-up scrollback navigation inside the alt-screen (where the host terminal’s native scrollback is unavailable).

fn scroll_body_to_top(&mut self)

Jump the body viewport to the absolute top / bottom of scrollback. Used for Home / End key handling.

fn scroll_body_to_bottom(&mut self)

fn begin_selection(&mut self, _col: u16, _row: u16)

Mouse text-selection hooks. Backends that own mouse capture can override these; streaming/native-scrollback backends keep host terminal selection behavior and no-op here.

fn update_selection(&mut self, _col: u16, _row: u16)

fn end_selection(&mut self)

fn copy_selection(&mut self) -> bool

Copy the current mouse-selection text to the system clipboard (using arboard, not OSC 52) and clear the selection highlight. Returns true if a non-empty selection was copied.

fn refresh_welcome_banner(&mut self, _model: &str, _working_dir: &str)

Update the cached welcome banner’s model / working_dir fields in place and trigger a repaint of the banner rows. Used after the QR-onboarding /codingplan claim finishes: the banner was painted at the top of scrollback with model="" (the claim hadn’t picked a default provider yet) — once the claim writes ctx.model_name, this hook splices the resolved model into the existing banner rows so the user doesn’t see a permanently blank model bullet.