fix: refresh diff colors on terminal theme changes

src/tui.rs

@@ -62,6 +62,19 @@ struct TerminalSession {
     hook: Arc<Mutex<HookState>>,
 }
 
+struct ColorSchemeNotifications(bool);
+
+impl crossterm::Command for ColorSchemeNotifications {
+    fn write_ansi(&self, f: &mut impl std::fmt::Write) -> std::fmt::Result {
+        f.write_str(if self.0 { "\x1b[?2031h" } else { "\x1b[?2031l" })
+    }
+
+    #[cfg(windows)]
+    fn execute_winapi(&self) -> io::Result<()> {
+        Ok(())
+    }
+}
+
 fn restore_terminal() {
     let _ = disable_raw_mode();
     let _ = execute!(
@@ -70,6 +83,7 @@ fn restore_terminal() {
         DisableBracketedPaste,
         DisableMouseCapture,
         DisableFocusChange,
+        ColorSchemeNotifications(false),
         LeaveAlternateScreen,
         Show
     );
@@ -109,7 +123,8 @@ impl TerminalSession {
                 EnterAlternateScreen,
                 EnableBracketedPaste,
                 EnableMouseCapture,
-                EnableFocusChange
+                EnableFocusChange,
+                ColorSchemeNotifications(true)
             )?;
             body()
         }));
@@ -787,7 +802,7 @@ pub fn run(session: &mut EditorSession) -> io::Result<()> {
                     pending = following;
                 }
                 Event::Resize(_, _) => redraw = true,
-                Event::FocusGained => query_theme = true,
+                Event::FocusGained | Event::ColorSchemeChanged => query_theme = true,
                 _ => {}
             }
         }
@@ -2982,8 +2997,8 @@ impl DiffColors {
             Color::Rgb(channels[0], channels[1], channels[2])
         };
         Self {
-            row: [blend(theme.red, 12), blend(theme.green, 12)],
-            character: [blend(theme.red, 28), blend(theme.green, 28)],
+            row: [blend(theme.red, 18), blend(theme.green, 18)],
+            character: [blend(theme.red, 38), blend(theme.green, 38)],
         }
     }
 }
@@ -4247,19 +4262,7 @@ mod tests {
 
     #[test]
     fn character_diff_backgrounds_preserve_common_unicode_and_syntax_across_viewports() {
-        for (theme, row, character) in [
-            (
-                Some(LIGHT_DIFF_THEME),
-                [Color::Rgb(245, 219, 217), Color::Rgb(222, 234, 218)],
-                [Color::Rgb(239, 185, 187), Color::Rgb(186, 218, 190)],
-            ),
-            (
-                Some(DARK_DIFF_THEME),
-                [Color::Rgb(44, 29, 36), Color::Rgb(22, 44, 38)],
-                [Color::Rgb(76, 35, 44), Color::Rgb(26, 68, 50)],
-            ),
-            (None, [Color::Reset; 2], [Color::Reset; 2]),
-        ] {
+        for theme in [Some(LIGHT_DIFF_THEME), Some(DARK_DIFF_THEME), None] {
             let mut diff = diff_comparison(vec![syntax_diff_file(
                 "changes.rs",
                 "let 界e\u{301} = old + old;",
@@ -4272,6 +4275,36 @@ mod tests {
                 ..WheelPanels::default()
             };
             render_diff(&mut terminal, &diff, &mut panels);
+            let row = panels.diff_colors.row;
+            let character = panels.diff_colors.character;
+            if let Some(theme) = theme {
+                for (index, accent) in [theme.red, theme.green].into_iter().enumerate() {
+                    let Color::Rgb(r, g, b) = row[index] else {
+                        panic!("theme row background must be RGB");
+                    };
+                    let Color::Rgb(cr, cg, cb) = character[index] else {
+                        panic!("theme character background must be RGB");
+                    };
+                    for ((common, changed), (background, accent)) in [r, g, b]
+                        .into_iter()
+                        .zip([cr, cg, cb])
+                        .zip(theme.background.into_iter().zip(accent))
+                    {
+                        assert!(
+                            (background.min(accent)..=background.max(accent)).contains(&common)
+                        );
+                        assert!(
+                            (background.min(accent)..=background.max(accent)).contains(&changed)
+                        );
+                        if background != accent {
+                            assert!(changed.abs_diff(accent) < common.abs_diff(accent));
+                        }
+                    }
+                }
+            } else {
+                assert_eq!(row, [Color::Reset; 2]);
+                assert_eq!(character, [Color::Reset; 2]);
+            }
             for index in 0..2 {
                 let pane = panels.diff.as_ref().unwrap().regions[index + 1].0;
                 let buffer = terminal.backend().buffer();