Struct ScrollBuffer 

pub struct ScrollBuffer { /* private fields */ }

Scrollable buffer of rendered Lines with sticky-bottom auto-scroll.

Implementations

impl ScrollBuffer

pub fn new(capacity: usize) -> Self

pub fn push(&mut self, line: Line<'static>)

Append a single line to the buffer.

If sticky bottom is active, the view stays pinned to the latest content. If the buffer exceeds the max cache size, the oldest lines are evicted from the front.

pub fn push_with_gutter(&mut self, line: Line<'static>, gutter_width: u16)

Append a line with a gutter width (for NoSelect diff lines).

pub fn push_lines(&mut self, lines: impl IntoIterator<Item = Line<'static>>)

Append multiple lines at once.

pub fn scroll_up(&mut self, n: usize, term_width: usize, viewport_height: usize)

Scroll up by n visual lines. Disengages sticky bottom.

pub fn scroll_down(&mut self, n: usize)

Scroll down by n lines. Re-engages sticky bottom if we reach the bottom.

pub fn clamp_offset(&mut self, term_width: usize, viewport_height: usize)

Re-clamp scroll_offset to valid bounds for the current terminal dimensions. Must be called after any resize so the offset doesn’t exceed total_visual - viewport_height.

pub fn scroll_to_bottom(&mut self)

Jump to the bottom and re-engage sticky mode.

pub fn scroll_to_top(&mut self, term_width: usize, viewport_height: usize)

Jump to the top of the buffer.

pub fn at_top(&self, term_width: usize, viewport_height: usize) -> bool

Returns true when the user has scrolled to the very top of the buffer. Used to trigger loading older messages from the DB.

pub fn all_lines(&self) -> impl Iterator<Item = &Line<'static>>

Return all lines in the buffer.

Used by render_history() which passes everything to Paragraph::wrap().scroll() — ratatui handles the visual line math for word-wrapped content.

pub fn gutter_widths(&self) -> &VecDeque<u16>

Return the per-line gutter widths (parallel with all_lines()).

Used by mouse selection to skip gutter columns during copy.

pub fn total_visual_lines(&self, term_width: usize) -> usize

Compute the total number of visual (wrapped) lines at a given terminal width. Used for scrollbar state and offset clamping.

pub fn paragraph_scroll( &self, viewport_height: usize, term_width: usize, ) -> (u16, u16)

Compute the Paragraph scroll-from-top offset for the current scroll position. Returns (row_offset, 0) for Paragraph::scroll().

scroll_offset is visual lines from the bottom. Paragraph wants visual lines from the top.

pub fn len(&self) -> usize

Total number of lines in the buffer.

pub fn is_empty(&self) -> bool

Whether the buffer is empty.

pub fn offset(&self) -> usize

Current scroll offset (lines from bottom).

pub fn is_sticky(&self) -> bool

Whether sticky bottom is active.

pub fn oldest_message_id(&self) -> Option<i64>

Get the oldest DB message ID rendered in this buffer.

pub fn set_oldest_message_id(&mut self, id: i64)

Set the oldest DB message ID (called after rendering history).

pub fn clear(&mut self)

Clear all lines and reset scroll state.

pub fn last_code_block(&self) -> Option<String>

Extract the last fenced code block from the buffer.

Scans backward for ``` fences and returns the content between them. Used by Ctrl+Y (copy last code block).

pub fn last_response(&self) -> Option<String>

Extract the last assistant response from the buffer.

Scans backward for the response separator (“───”) and returns everything after it. Used by Ctrl+U / Ctrl+Shift+Y (copy last response).

The separator is exactly 3 ─ characters (emitted by ResponseStart). Markdown HRs (60+ dashes) are explicitly excluded.

pub fn prepend_lines(&mut self, lines: impl IntoIterator<Item = Line<'static>>)

Prepend lines at the top of the buffer (for DB-backed virtual scroll).

Used when the user scrolls past the top of the cache and older messages are fetched from the DB and re-rendered.