feat: add horizontal scroll for diff viewer and file list panels

Author: code0xff

src/app.rs

@@ -117,6 +117,8 @@ pub struct App {
     pub selected: usize,
     pub hunks: Vec<DiffHunk>,
     pub scroll: usize,
+    pub diff_scroll_x: usize,
+    pub file_scroll_x: usize,
     pub focus: Focus,
     pub status: Option<String>,
     pub repo_path: String,
@@ -163,6 +165,8 @@ impl App {
             selected: 0,
             hunks: Vec::new(),
             scroll: 0,
+            diff_scroll_x: 0,
+            file_scroll_x: 0,
             focus: Focus::FileList,
             status: None,
             repo_path,
@@ -335,6 +339,7 @@ impl App {
         self.selected = 0;
         self.hunks.clear();
         self.scroll = 0;
+        self.diff_scroll_x = 0;
         self.commits.clear();
         self.log_selected = 0;
         self.log_diff_title.clear();
@@ -508,6 +513,7 @@ impl App {
                     self.hunks = hunks;
                     if reset_scroll {
                         self.scroll = 0;
+                        self.diff_scroll_x = 0;
                         self.diff_search_cursor = 0;
                     } else {
                         self.scroll = previous_scroll;
@@ -531,6 +537,7 @@ impl App {
         self.diff_search_matches.clear();
         self.diff_search_cursor = 0;
         self.scroll = 0;
+        self.diff_scroll_x = 0;
     }
 
     fn restore_selection(&mut self, previous_path: Option<&str>) -> Option<String> {
@@ -643,6 +650,22 @@ impl App {
         self.diff_line_count().saturating_sub(1)
     }
 
+    pub fn diff_scroll_left(&mut self) {
+        self.diff_scroll_x = self.diff_scroll_x.saturating_sub(4);
+    }
+
+    pub fn diff_scroll_right(&mut self) {
+        self.diff_scroll_x = self.diff_scroll_x.saturating_add(4);
+    }
+
+    pub fn file_scroll_left(&mut self) {
+        self.file_scroll_x = self.file_scroll_x.saturating_sub(4);
+    }
+
+    pub fn file_scroll_right(&mut self) {
+        self.file_scroll_x = self.file_scroll_x.saturating_add(4);
+    }
+
     fn recompute_diff_matches(&mut self, scroll_to_match: bool) {
         self.diff_search_matches.clear();
         if self.diff_search_query.is_empty() {
@@ -824,6 +847,7 @@ impl App {
                 Ok(hunks) => {
                     self.hunks = hunks;
                     self.scroll = 0;
+                    self.diff_scroll_x = 0;
                     self.log_diff_title = title;
                     if !self.diff_search_query.is_empty() {
                         self.recompute_diff_matches(true);
@@ -926,6 +950,7 @@ impl App {
             Ok(hunks) => {
                 self.hunks = hunks;
                 self.scroll = 0;
+                self.diff_scroll_x = 0;
                 self.log_diff_title = title;
                 if !self.diff_search_query.is_empty() {
                     self.recompute_diff_matches(true);
@@ -1164,6 +1189,8 @@ mod tests {
             selected: 0,
             hunks: Vec::new(),
             scroll: 0,
+            diff_scroll_x: 0,
+            file_scroll_x: 0,
             focus: Focus::FileList,
             status: None,
             repo_path: ".".to_string(),

src/main.rs

@@ -383,13 +383,17 @@ fn handle_unmapped_upper_key(app: &mut App, key: KeyEvent) {
             KeyCode::Esc if app.log_drill_down => app.log_drill_out(),
             KeyCode::Char('/') if app.mode == ViewMode::Status => app.start_search(),
             KeyCode::Esc if !app.search_query.is_empty() => app.cancel_search(),
+            KeyCode::Left => app.file_scroll_left(),
+            KeyCode::Right => app.file_scroll_right(),
             _ => {}
         },
         Focus::DiffViewer => match key.code {
             KeyCode::Char('/') => app.start_diff_search(),
             KeyCode::Char('n') => app.next_diff_match(),
             KeyCode::Char('N') => app.prev_diff_match(),
             KeyCode::Esc if !app.diff_search_query.is_empty() => app.cancel_diff_search(),
+            KeyCode::Left => app.diff_scroll_left(),
+            KeyCode::Right => app.diff_scroll_right(),
             _ => {}
         },
         Focus::Terminal => {}

src/ui/diff_viewer.rs

@@ -215,12 +215,14 @@ pub fn render(
         .take(visible_height)
         .collect();
 
-    let para = Paragraph::new(visible_lines).block(
-        Block::default()
-            .borders(Borders::ALL)
-            .title(title)
-            .border_style(border_style),
-    );
+    let para = Paragraph::new(visible_lines)
+        .block(
+            Block::default()
+                .borders(Borders::ALL)
+                .title(title)
+                .border_style(border_style),
+        )
+        .scroll((0, app.diff_scroll_x as u16));
 
     frame.render_widget(para, diff_area);
 

src/ui/file_list.rs

@@ -32,9 +32,20 @@ pub fn render(frame: &mut Frame, app: &App, area: Rect, accent: Color) {
             let f = &app.files[idx];
             let symbol = f.status.symbol();
             let color = super::status_color(f.status);
+            let path: &str = if app.file_scroll_x == 0 {
+                &f.path
+            } else {
+                let byte_off = f
+                    .path
+                    .char_indices()
+                    .nth(app.file_scroll_x)
+                    .map(|(b, _)| b)
+                    .unwrap_or(f.path.len());
+                &f.path[byte_off..]
+            };
             let line = Line::from(vec![
                 Span::styled(format!("{symbol} "), Style::default().fg(color)),
-                Span::raw(&f.path),
+                Span::raw(path.to_owned()),
             ]);
             ListItem::new(line)
         })