Skip to content

fix: selection follows scroll and auto-scrolls at viewport edges #20

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
190km merged 2 commits into from
Mar 29, 2026
Merged

fix: selection follows scroll and auto-scrolls at viewport edges #20

Changes from all commits
Commits
Show all changes
2 commits
Select commit Hold shift + click to select a range
7d8ba86
fix: selection follows scroll and auto-scrolls at edges
190km Mar 29, 2026
47d293d
fix: selection coordinates use i32 to support scrolling in both direc…
190km Mar 29, 2026
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
147 changes: 102 additions & 45 deletions src/terminal/panel.rs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -81,9 +81,9 @@ pub struct TerminalPanel {
last_cols: u16,
last_rows: u16,
spawn_error: Option<String>,
// Selection state — viewport cell coordinates at the time of selection.
// Rows are relative to the viewport when selection_display_offset was captured.
selection: Option<(usize, usize, usize, usize)>, // (start_col, start_row, end_col, end_row)
// Selection state — cell coordinates relative to selection_display_offset.
// Rows can be negative (content scrolled above viewport).
selection: Option<(i32, i32, i32, i32)>, // (start_col, start_row, end_col, end_row)
selection_display_offset: usize,
selecting: bool,
scroll_remainder: f32,
Expand Down Expand Up @@ -409,6 +409,25 @@ impl TerminalPanel {
}
}

/// Scroll the terminal during active selection, keeping selection coordinates in sync.
fn auto_scroll_selection(&mut self, lines: i32) {
if let Some(pty) = &self.pty {
if let Ok(mut term) = pty.term.lock() {
let old_offset = term.grid().display_offset();
term.scroll_display(alacritty_terminal::grid::Scroll::Delta(lines));
let new_offset = term.grid().display_offset();
let delta = new_offset as i32 - old_offset as i32;
if delta != 0 {
if let Some(ref mut sel) = self.selection {
sel.1 += delta;
sel.3 += delta;
}
self.selection_display_offset = new_offset;
}
}
}
}

pub fn handle_input(&mut self, ctx: &egui::Context) {
if !self.focused {
return;
Expand Down Expand Up @@ -489,22 +508,29 @@ impl TerminalPanel {
}

/// Convert pointer position to terminal cell (col, row), clamped to grid bounds.
fn pos_to_cell(&self, pos: Pos2, body: Rect, ctx: &egui::Context) -> (usize, usize) {
fn pos_to_cell(&self, pos: Pos2, body: Rect, ctx: &egui::Context) -> (i32, i32) {
let (cw, ch) = crate::terminal::renderer::cell_size(ctx);
let col = ((pos.x - body.min.x - crate::terminal::renderer::PAD_X) / cw)
.floor()
.clamp(0.0, (self.last_cols as f32) - 1.0) as usize;
.clamp(0.0, (self.last_cols as f32) - 1.0) as i32;
let row = ((pos.y - body.min.y - crate::terminal::renderer::PAD_Y) / ch)
.floor()
.clamp(0.0, (self.last_rows as f32) - 1.0) as usize;
.clamp(0.0, (self.last_rows as f32) - 1.0) as i32;
(col, row)
}

fn selected_text(&self) -> Option<String> {
let (sc, sr, ec, er) = self.selection?;
let pty = self.pty.as_ref()?;
let term = pty.term.lock().ok()?;
let text = extract_selection_text(&term, sc, sr, ec, er, self.selection_display_offset);
let text = extract_selection_text(
&term,
sc.max(0) as usize,
sr.max(0) as usize,
ec.max(0) as usize,
er.max(0) as usize,
self.selection_display_offset,
);
if text.is_empty() {
None
} else {
Expand Down Expand Up @@ -772,31 +798,21 @@ impl TerminalPanel {
let (cw, ch) = crate::terminal::renderer::cell_size(ui.ctx());
let pad_x = crate::terminal::renderer::PAD_X;
let pad_y = crate::terminal::renderer::PAD_Y;
let max_col = self.last_cols as usize;
let max_col = self.last_cols as i32;
let max_row = self.last_rows as i32;

let (start_row, start_col, end_row, end_col) = if sr < er || (sr == er && sc <= ec)
{
(
sr,
sc.min(max_col.saturating_sub(1)),
er,
ec.min(max_col.saturating_sub(1)),
)
(sr, sc.min(max_col - 1), er, ec.min(max_col - 1))
} else {
(
er,
ec.min(max_col.saturating_sub(1)),
sr,
sc.min(max_col.saturating_sub(1)),
)
(er, ec.min(max_col - 1), sr, sc.min(max_col - 1))
};

// Adjust rows for scroll: positive delta = scrolled back = rows move down
// Adjust rows for scroll delta since selection was made
let current_offset = scrollbar_state.map(|s| s.display_offset).unwrap_or(0) as i32;
let offset_delta = current_offset - self.selection_display_offset as i32;
let adj_start = start_row as i32 + offset_delta;
let adj_end = end_row as i32 + offset_delta;
let adj_start = start_row + offset_delta;
let adj_end = end_row + offset_delta;

let screen_content =
Rect::from_min_max(transform * content_rect.min, transform * content_rect.max)
Expand All @@ -809,21 +825,20 @@ impl TerminalPanel {
if row_i < 0 || row_i >= max_row {
continue;
}
let row = row_i as usize;
let orig_row = row_i - offset_delta; // original selection row
let c0 = if orig_row == start_row as i32 {
start_col
let orig_row = row_i - offset_delta;
let c0 = if orig_row == start_row {
start_col.max(0)
} else {
0
};
let c1 = (if orig_row == end_row as i32 {
let c1 = (if orig_row == end_row {
end_col + 1
} else {
max_col
})
.min(max_col);
let x0 = content_rect.min.x + pad_x + c0 as f32 * cw;
let y0 = content_rect.min.y + pad_y + row as f32 * ch;
let y0 = content_rect.min.y + pad_y + row_i as f32 * ch;
let x1 = content_rect.min.x + pad_x + c1 as f32 * cw;
let sel_rect = Rect::from_min_max(
transform * Pos2::new(x0, y0),
Expand Down Expand Up @@ -1078,8 +1093,10 @@ impl TerminalPanel {
// Double-click: select word
if let Some(pos) = body_resp.interact_pointer_pos() {
let (col, row) = self.pos_to_cell(pos, content_rect, ui.ctx());
if let Some((start, end)) = self.word_boundaries_at(col, row) {
self.selection = Some((start, row, end, row));
if let Some((start, end)) =
self.word_boundaries_at(col as usize, row as usize)
{
self.selection = Some((start as i32, row, end as i32, row));
self.selection_display_offset =
scrollbar_state.map(|s| s.display_offset).unwrap_or(0);
}
Expand All @@ -1089,7 +1106,7 @@ impl TerminalPanel {
// Triple-click: select entire line
if let Some(pos) = body_resp.interact_pointer_pos() {
let (_, row) = self.pos_to_cell(pos, content_rect, ui.ctx());
let last_col = (self.last_cols as usize).saturating_sub(1);
let last_col = (self.last_cols as i32) - 1;
self.selection = Some((0, row, last_col, row));
self.selection_display_offset =
scrollbar_state.map(|s| s.display_offset).unwrap_or(0);
Expand All @@ -1112,21 +1129,59 @@ impl TerminalPanel {
self.selecting = true;
}
}

if local_interactions_enabled
&& self.selecting
&& body_resp.dragged_by(egui::PointerButton::Primary)
{
if let Some(pos) = body_resp.hover_pos() {
let (col, row) = self.pos_to_cell(pos, content_rect, ui.ctx());
if let Some(ref mut sel) = self.selection {
sel.2 = col;
sel.3 = row;
// Check for auto-scroll when pointer is above or below terminal
let mut auto_scrolled = false;
if let Some(screen_pos) = ui.ctx().input(|i| i.pointer.latest_pos()) {
let canvas_pos = transform.inverse() * screen_pos;
let (_, row_height) = crate::terminal::renderer::cell_size(ui.ctx());

if canvas_pos.y < content_rect.min.y {
// Pointer above terminal: auto-scroll up (towards history)
let distance = content_rect.min.y - canvas_pos.y;
let lines = ((distance / (row_height * 3.0)).ceil() as i32).max(1);
self.auto_scroll_selection(lines);
if let Some(ref mut sel) = self.selection {
sel.2 = 0;
sel.3 = 0;
}
auto_scrolled = true;
ui.ctx().request_repaint();
} else if canvas_pos.y > content_rect.max.y {
// Pointer below terminal: auto-scroll down (towards recent)
let distance = canvas_pos.y - content_rect.max.y;
let lines = -(((distance / (row_height * 3.0)).ceil() as i32).max(1));
self.auto_scroll_selection(lines);
if let Some(ref mut sel) = self.selection {
sel.2 = (self.last_cols as i32) - 1;
sel.3 = (self.last_rows as i32) - 1;
}
auto_scrolled = true;
ui.ctx().request_repaint();
}
} else if let Some(pos) = body_resp.interact_pointer_pos() {
let (col, row) = self.pos_to_cell(pos, content_rect, ui.ctx());
if let Some(ref mut sel) = self.selection {
sel.2 = col;
sel.3 = row;
}

if !auto_scrolled {
// Convert viewport row to original selection offset coordinate
let current_offset = scrollbar_state.map(|s| s.display_offset).unwrap_or(0) as i32;
let offset_delta = current_offset - self.selection_display_offset as i32;

if let Some(pos) = body_resp.hover_pos() {
let (col, row) = self.pos_to_cell(pos, content_rect, ui.ctx());
if let Some(ref mut sel) = self.selection {
sel.2 = col;
sel.3 = row - offset_delta;
}
} else if let Some(pos) = body_resp.interact_pointer_pos() {
let (col, row) = self.pos_to_cell(pos, content_rect, ui.ctx());
if let Some(ref mut sel) = self.selection {
sel.2 = col;
sel.3 = row - offset_delta;
}
}
}
}
Expand All @@ -1143,7 +1198,9 @@ impl TerminalPanel {
+ if mods.ctrl { 16 } else { 0 };

// Helper: send SGR mouse event
let send_mouse = |btn: u8, col: usize, row: usize, press: bool| {
let send_mouse = |btn: u8, col: i32, row: i32, press: bool| {
let col = col.max(0) as usize;
let row = row.max(0) as usize;
let suffix = if press { 'M' } else { 'm' };
let seq = format!("\x1b[<{};{};{}{}", btn + mod_bits, col + 1, row + 1, suffix);
pty.write(seq.as_bytes());
Expand Down Expand Up @@ -1257,8 +1314,8 @@ impl TerminalPanel {
ui.close_menu();
}
if ui.button("Select All").clicked() {
let last_col = (self.last_cols as usize).saturating_sub(1);
let last_row = (self.last_rows as usize).saturating_sub(1);
let last_col = (self.last_cols as i32) - 1;
let last_row = (self.last_rows as i32) - 1;
self.selection = Some((0, 0, last_col, last_row));
self.selection_display_offset =
scrollbar_state.map(|s| s.display_offset).unwrap_or(0);
Expand Down
Loading