Mouse selection support

helix-term/src/application.rs

@@ -15,7 +15,7 @@ use std::{
 use anyhow::Error;
 
 use crossterm::{
-    event::{Event, EventStream},
+    event::{DisableMouseCapture, EnableMouseCapture, Event, EventStream},
     execute, terminal,
 };
 
@@ -449,13 +449,17 @@ impl Application {
         let mut stdout = stdout();
 
         execute!(stdout, terminal::EnterAlternateScreen)?;
+        if self.config.terminal.mouse {
+            execute!(stdout, EnableMouseCapture)?;
+        }
 
         // Exit the alternate screen and disable raw mode before panicking
         let hook = std::panic::take_hook();
         std::panic::set_hook(Box::new(move |info| {
             // We can't handle errors properly inside this closure.  And it's
             // probably not a good idea to `unwrap()` inside a panic handler.
             // So we just ignore the `Result`s.
+            let _ = execute!(std::io::stdout(), DisableMouseCapture);
             let _ = execute!(std::io::stdout(), terminal::LeaveAlternateScreen);
             let _ = terminal::disable_raw_mode();
             hook(info);
@@ -468,6 +472,7 @@ impl Application {
         // reset cursor shape
         write!(stdout, "\x1B[2 q")?;
 
+        execute!(stdout, DisableMouseCapture)?;
         execute!(stdout, terminal::LeaveAlternateScreen)?;
 
         terminal::disable_raw_mode()?;

helix-term/src/config.rs

@@ -9,6 +9,8 @@ pub struct Config {
     pub lsp: LspConfig,
     #[serde(default)]
     pub keys: Keymaps,
+    #[serde(default)]
+    pub terminal: TerminalConfig,
 }
 
 #[derive(Debug, Default, Clone, PartialEq, Deserialize)]
@@ -17,6 +19,18 @@ pub struct LspConfig {
     pub display_messages: bool,
 }
 
+#[derive(Debug, Clone, PartialEq, Deserialize)]
+#[serde(rename_all = "kebab-case")]
+pub struct TerminalConfig {
+    pub mouse: bool,
+}
+
+impl Default for TerminalConfig {
+    fn default() -> Self {
+        Self { mouse: true }
+    }
+}
+
 #[test]
 fn parsing_keymaps_config_file() {
     use crate::keymap;

helix-term/src/ui/editor.rs

@@ -12,7 +12,7 @@ use helix_core::{
     syntax::{self, HighlightEvent},
     unicode::segmentation::UnicodeSegmentation,
     unicode::width::UnicodeWidthStr,
-    LineEnding, Position, Range,
+    LineEnding, Position, Range, Selection,
 };
 use helix_view::{
     document::Mode,
@@ -24,7 +24,7 @@ use helix_view::{
 };
 use std::borrow::Cow;
 
-use crossterm::event::Event;
+use crossterm::event::{Event, MouseButton, MouseEvent, MouseEventKind};
 use tui::buffer::Buffer as Surface;
 
 pub struct EditorView {
@@ -770,6 +770,72 @@ impl Component for EditorView {
 
                 EventResult::Consumed(callback)
             }
+            Event::Mouse(MouseEvent {
+                kind: MouseEventKind::Down(MouseButton::Left),
+                row,
+                column,
+                modifiers,
+                ..
+            }) => {
+                let editor = &mut cx.editor;
+
+                let result = editor.tree.views().find_map(|(view, _focus)| {
+                    if !view.verify_screen_coords(row as usize, column as usize) {
+                        return None;
+                    }
+
+                    Some((
+                        view.pos_at_screen_coords(
+                            &editor.documents[view.doc],
+                            row as usize,
+                            column as usize,
+                        ),
+                        view.id,
+                    ))
+                });
+
+                let tree = &mut editor.tree;
+
+                if let Some((pos, id)) = result {
+                    let doc = &mut editor.documents[tree.get(id).doc];
+                    let jump = (doc.id(), doc.selection(id).clone());
+                    tree.get_mut(id).jumps.push(jump);
+
+                    if modifiers == crossterm::event::KeyModifiers::ALT {
+                        let selection = doc.selection(id).clone();
+                        doc.set_selection(id, selection.push(Range::point(pos)));
+                    } else {
+                        doc.set_selection(id, Selection::point(pos));
+                    }
+
+                    cx.editor.tree.focus = id;
+
+                    return EventResult::Consumed(None);
+                }
+
+                EventResult::Ignored
+            }
+
+            Event::Mouse(MouseEvent {
+                kind: MouseEventKind::Drag(MouseButton::Left),
+                row,
+                column,
+                ..
+            }) => {
+                let (view, doc) = current!(cx.editor);
+
+                if !view.verify_screen_coords(row as usize, column as usize) {
+                    return EventResult::Ignored;
+                }
+
+                let pos = view.pos_at_screen_coords(doc, row as usize, column as usize);
+
+                let selection = doc.selection(view.id).clone();
+                let primary = selection.primary();
+
+                doc.set_selection(view.id, selection.push(Range::new(primary.anchor, pos)));
+                EventResult::Consumed(None)
+            }
             Event::Mouse(_) => EventResult::Ignored,
         }
     }

helix-view/src/view.rs

@@ -161,6 +161,58 @@ impl View {
         Some(Position::new(row, col))
     }
 
+    /// Verifies whether a screen position is inside the view
+    /// Returns true when position is inside the view
+    pub fn verify_screen_coords(&self, row: usize, column: usize) -> bool {
+        // 2 for status
+        if row < self.area.y as usize || row > self.area.y as usize + self.area.height as usize - 2
+        {
+            return false;
+        }
+
+        // TODO: not ideal
+        const OFFSET: usize = 7; // 1 diagnostic + 5 linenr + 1 gutter
+
+        if column < self.area.x as usize + OFFSET
+            || column > self.area.x as usize + self.area.width as usize
+        {
+            return false;
+        }
+        true
+    }
+
+    /// Translates a screen position to position in the text document.
+    /// Returns a usize typed position in bounds of the text if found in this view, panics if out of view.
+    pub fn pos_at_screen_coords(&self, doc: &Document, row: usize, column: usize) -> usize {
+        let text = doc.text();
+        let line_number = row - self.area.y as usize + self.first_line;
+        let mut pos = text.line_to_char(line_number);
+
+        let current_line = text.line(line_number);
+        let tab_width = doc.tab_width();
+
+        // TODO: not ideal
+        const OFFSET: usize = 7; // 1 diagnostic + 5 linenr + 1 gutter
+
+        let target = column - OFFSET - self.area.x as usize + self.first_col;
+        let mut selected = 0;
+
+        for grapheme in RopeGraphemes::new(current_line) {
+            if selected > target {
+                break;
+            }
+            if grapheme == "\t" {
+                selected += tab_width;
+            } else if grapheme != "\n" {
+                let width = grapheme_width(&Cow::from(grapheme));
+                selected += width;
+            }
+            pos += 1;
+        }
+
+        pos - 1
+    }
+
     // pub fn traverse<F>(&self, text: RopeSlice, start: usize, end: usize, fun: F)
     // where
     //     F: Fn(usize, usize),