Add Scrollable Source page

src/main.rs

@@ -309,6 +309,7 @@ struct State {
     current_source_file: Option<String>,
     current_source_line: Option<u32>,
     source_lines: Vec<String>,
+    source_scroll: Scroll,
     /// Current source language detected by GDB
     source_language: Option<String>,
     /// Symbol browser
@@ -365,6 +366,7 @@ impl State {
             current_source_file: None,
             current_source_line: None,
             source_lines: Vec::new(),
+            source_scroll: Scroll::default(),
             source_language: None,
             symbols: Vec::new(),
             symbols_scroll: Scroll::default(),
@@ -1192,6 +1194,34 @@ fn run_app<B: Backend>(
                         state.symbols_scroll.reset();
                     }
                 }
+                // source scrolling
+                (InputMode::Normal, KeyCode::Char('g'), Mode::OnlySource) => {
+                    let mut state = state_share.state.lock().unwrap();
+                    state.source_scroll.reset();
+                }
+                (InputMode::Normal, KeyCode::Char('G'), Mode::OnlySource) => {
+                    let mut state = state_share.state.lock().unwrap();
+                    let len = state.source_lines.len();
+                    state.source_scroll.end(len);
+                }
+                (InputMode::Normal, KeyCode::Char('j'), Mode::OnlySource) => {
+                    let mut state = state_share.state.lock().unwrap();
+                    let len = state.source_lines.len();
+                    state.source_scroll.down(1, len);
+                }
+                (InputMode::Normal, KeyCode::Char('k'), Mode::OnlySource) => {
+                    let mut state = state_share.state.lock().unwrap();
+                    state.source_scroll.up(1);
+                }
+                (InputMode::Normal, KeyCode::Char('J'), Mode::OnlySource) => {
+                    let mut state = state_share.state.lock().unwrap();
+                    let len = state.source_lines.len();
+                    state.source_scroll.down(50, len);
+                }
+                (InputMode::Normal, KeyCode::Char('K'), Mode::OnlySource) => {
+                    let mut state = state_share.state.lock().unwrap();
+                    state.source_scroll.up(50);
+                }
                 (_, KeyCode::Tab, _) => {
                     let mut state = state_share.state.lock().unwrap();
                     completion(app, &mut state)?;

src/ui/source.rs

@@ -33,14 +33,10 @@ pub fn draw_source(state: &mut State, f: &mut Frame, area: Rect) {
     let current_line = state.current_source_line.unwrap() as usize;
     let total_lines = state.source_lines.len();
 
-    // Calculate which lines to show (center the current line in the view)
+    // Calculate which lines to show based on scroll position
     // Account for borders and title
     let lines_to_show = (area.height as usize).saturating_sub(3);
-    let start_line = if current_line > lines_to_show / 2 {
-        (current_line.saturating_sub(lines_to_show / 2)).saturating_sub(1)
-    } else {
-        0
-    };
+    let start_line = state.source_scroll.scroll.min(total_lines.saturating_sub(1));
     let end_line = (start_line + lines_to_show).min(total_lines);
 
     let theme = arborium::theme::builtin::ayu_dark();