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Merged
enijburg merged 1 commit into from
May 15, 2026
Merged

Add mouse/keyboard text selection with clipboard copy feedback #14

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1 change: 1 addition & 0 deletions Cargo.toml
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Original file line number Diff line number Diff line change
Expand Up @@ -8,6 +8,7 @@ anyhow = "1.0"
clap = { version = "4.5", features = ["derive"] }
crossterm = "0.29"
memmap2 = "0.9"
arboard = "3.6"

[[bin]]
name = "lfv"
Expand Down
163 changes: 159 additions & 4 deletions src/main.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -7,10 +7,11 @@ use std::{
};

use anyhow::{Context, Result};
use arboard::Clipboard;
use clap::Parser;
use crossterm::{
cursor,
event::{self, Event, KeyCode, KeyEventKind, MouseButton, MouseEventKind},
event::{self, Event, KeyCode, KeyEventKind, KeyModifiers, MouseButton, MouseEventKind},
execute, queue,
style::{self, Color, Stylize},
terminal::{self, ClearType},
Expand Down Expand Up @@ -61,6 +62,10 @@ struct Viewer {
json_syntax_highlighting: bool,
search_query: Option<Vec<u8>>,
match_range: Option<(usize, usize)>,
cursor_offset: usize,
selection_anchor: Option<usize>,
selection_focus: Option<usize>,
status_message: Option<String>,
}

#[derive(Clone, Copy, Debug, PartialEq, Eq)]
Expand Down Expand Up @@ -195,6 +200,10 @@ impl Viewer {
json_syntax_highlighting,
search_query: None,
match_range: None,
cursor_offset: 0,
selection_anchor: None,
selection_focus: None,
status_message: None,
})
}

Expand Down Expand Up @@ -310,7 +319,10 @@ impl Viewer {

self.render_scrollbar(out, width, body_rows)?;

let footer = "Memory-mapped view (renders visible window only)";
let footer = self
.status_message
.as_deref()
.unwrap_or("Memory-mapped view (renders visible window only)");
let clipped_footer = clip_to_width(footer, width);
let y = height.saturating_sub(1);
queue!(
Expand Down Expand Up @@ -340,6 +352,13 @@ impl Viewer {
}
});

let selection = self.selection_range().and_then(|(start, end)| {
if start < line_end && end > line_start {
Some((start, end))
} else {
None
}
});
let bytes = &view_bytes[line_start..line_end];
let content_start = skipped_prefix_len(line_idx, bytes);
let mut segments: Vec<(bool, RenderClass, String)> = Vec::new();
Expand Down Expand Up @@ -389,9 +408,13 @@ impl Viewer {
}

let absolute_idx = line_start + idx;
let is_highlight = highlight
let is_selected = selection
.map(|(start, end)| absolute_idx >= start && absolute_idx < end)
.unwrap_or(false);
let is_highlight = is_selected
|| highlight
.map(|(start, end)| absolute_idx >= start && absolute_idx < end)
.unwrap_or(false);

match b {
b if b == separator => {
Expand Down Expand Up @@ -427,9 +450,13 @@ impl Viewer {
}

let absolute_idx = line_start + idx;
let is_highlight = highlight
let is_selected = selection
.map(|(start, end)| absolute_idx >= start && absolute_idx < end)
.unwrap_or(false);
let is_highlight = is_selected
|| highlight
.map(|(start, end)| absolute_idx >= start && absolute_idx < end)
.unwrap_or(false);
let render_class = if self.json_syntax_highlighting {
match json_classes
.get(idx)
Expand Down Expand Up @@ -647,6 +674,46 @@ impl Viewer {
.rposition(|window| window == query)
.map(|found_start| (found_start, found_start + query.len()))
}

fn selection_range(&self) -> Option<(usize, usize)> {
let (a, b) = (self.selection_anchor?, self.selection_focus?);
if a == b {
None
} else {
Some((a.min(b), a.max(b)))
}
}

fn clear_selection(&mut self) {
self.selection_anchor = None;
self.selection_focus = None;
}

fn offset_for_line_col(&self, line_idx: usize, target_col: usize) -> usize {
let view = self.view_bytes();
let line_start = *self.line_offsets.get(line_idx).unwrap_or(&0);
let line_end = if line_idx + 1 < self.line_offsets.len() {
self.line_offsets[line_idx + 1]
} else {
view.len()
};
let bytes = &view[line_start..line_end];
let mut visual_col = 0usize;
for (idx, &b) in bytes
.iter()
.enumerate()
.skip(skipped_prefix_len(line_idx, bytes))
{
if b == b'\n' || b == b'\r' {
continue;
}
if visual_col >= target_col {
return line_start + idx;
}
visual_col += if b == b'\t' { self.tab_width } else { 1 };
}
line_end.saturating_sub(1)
}
}

fn clip_to_width(s: &str, max_width: usize) -> String {
Expand Down Expand Up @@ -1121,6 +1188,8 @@ fn main() -> Result<()> {
fn run_event_loop(viewer: &mut Viewer, out: &mut impl Write) -> Result<()> {
let mut needs_redraw = true;
let mut scrollbar_drag = false;
let mut selection_drag = false;
let mut clipboard = Clipboard::new().ok();

loop {
if needs_redraw {
Expand All @@ -1135,6 +1204,30 @@ fn run_event_loop(viewer: &mut Viewer, out: &mut impl Write) -> Result<()> {
let page = height.saturating_sub(2) as usize;
match key.code {
KeyCode::Char('q') => break,
KeyCode::Char('c') if key.modifiers.contains(KeyModifiers::CONTROL) => {
if let Some((start, end)) = viewer.selection_range() {
let copied =
String::from_utf8_lossy(&viewer.view_bytes()[start..end])
.to_string();
if let Some(cb) = clipboard.as_mut() {
if cb.set_text(copied).is_ok() {
viewer.status_message = Some(format!(
"Copied {} bytes to clipboard",
end - start
));
} else {
viewer.status_message = Some(
"Failed to copy selection to clipboard".to_string(),
);
}
} else {
viewer.status_message = Some(
"Clipboard unavailable in this environment".to_string(),
);
}
needs_redraw = true;
}
}
KeyCode::Char('g') => {
if let Some(line_number) = prompt_goto_line(viewer, out)? {
let target_line = line_number
Expand Down Expand Up @@ -1193,10 +1286,32 @@ fn run_event_loop(viewer: &mut Viewer, out: &mut impl Write) -> Result<()> {
}
KeyCode::Left => {
viewer.scroll_left(1);
if key.modifiers.contains(KeyModifiers::SHIFT) {
let anchor =
viewer.selection_anchor.unwrap_or(viewer.cursor_offset);
viewer.cursor_offset = viewer.cursor_offset.saturating_sub(1);
viewer.selection_anchor = Some(anchor);
viewer.selection_focus = Some(viewer.cursor_offset);
} else {
viewer.clear_selection();
viewer.cursor_offset = viewer.cursor_offset.saturating_sub(1);
}
needs_redraw = true;
}
KeyCode::Right => {
viewer.scroll_right(1);
if key.modifiers.contains(KeyModifiers::SHIFT) {
let anchor =
viewer.selection_anchor.unwrap_or(viewer.cursor_offset);
viewer.cursor_offset =
(viewer.cursor_offset + 1).min(viewer.view_bytes().len());
viewer.selection_anchor = Some(anchor);
viewer.selection_focus = Some(viewer.cursor_offset);
} else {
viewer.clear_selection();
viewer.cursor_offset =
(viewer.cursor_offset + 1).min(viewer.view_bytes().len());
}
needs_redraw = true;
}
KeyCode::Up => {
Expand Down Expand Up @@ -1240,12 +1355,52 @@ fn run_event_loop(viewer: &mut Viewer, out: &mut impl Write) -> Result<()> {
viewer.scroll_to_scrollbar_row(mouse.row as usize, body_rows);
needs_redraw = true;
}
MouseEventKind::Down(MouseButton::Left) => {
selection_drag = true;
let row = mouse.row as usize;
if row > 0 && row <= body_rows {
let line_idx = viewer.top_line + row - 1;
if line_idx < viewer.line_count() {
let col = viewer.left_col + mouse.column as usize;
let offset = viewer.offset_for_line_col(line_idx, col);
viewer.cursor_offset = offset;
viewer.selection_anchor = Some(offset);
viewer.selection_focus = Some(offset);
viewer.status_message = Some("Selecting text…".to_string());
needs_redraw = true;
}
}
}
MouseEventKind::Drag(MouseButton::Left) if scrollbar_drag => {
viewer.scroll_to_scrollbar_row(mouse.row as usize, body_rows);
needs_redraw = true;
}
MouseEventKind::Drag(MouseButton::Left) if selection_drag => {
let row = mouse.row as usize;
if row > 0 && row <= body_rows {
let line_idx = viewer.top_line + row - 1;
if line_idx < viewer.line_count() {
let col = viewer.left_col + mouse.column as usize;
let offset = viewer.offset_for_line_col(line_idx, col);
viewer.cursor_offset = offset;
viewer.selection_focus = Some(offset);
needs_redraw = true;
}
}
}
MouseEventKind::Up(MouseButton::Left) => {
scrollbar_drag = false;
if selection_drag {
selection_drag = false;
viewer.status_message =
viewer.selection_range().map(|(start, end)| {
format!(
"Selected {} bytes. Press Ctrl+C to copy.",
end - start
)
});
needs_redraw = true;
}
}
MouseEventKind::ScrollDown => {
viewer.scroll_down(3, body_rows);
Expand Down
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