fix: limit linewise highlighting to copied text

src/tui.rs

@@ -670,9 +670,13 @@ fn draw(
             let first = (*rows.start()).max(*top);
             let last = (*rows.end()).min(top.saturating_add(height - 1));
             for row in first..=last {
+                let end = display_column(&editor.lines()[row], usize::MAX)
+                    .saturating_add(1)
+                    .min(left.saturating_add(width));
                 let y = viewport.y + (row - *top) as u16;
-                for x in viewport.x..viewport.x + viewport.width {
-                    frame.buffer_mut()[(x, y)].set_style(selection_style);
+                for column in *left..end {
+                    frame.buffer_mut()[(viewport.x + (column - *left) as u16, y)]
+                        .set_style(selection_style);
                 }
             }
         }
@@ -5568,19 +5572,21 @@ end
     }
 
     #[test]
-    fn linewise_selection_fills_blank_and_final_rows_without_coloring_gutter() {
+    fn linewise_selection_highlights_copied_text_and_newlines_without_filling_rows() {
         let mut editor = Editor::open(None, vec![]).unwrap();
         editor
-            .apply(vec![crate::editor::Effect::Replace("long text\n\n".into())])
+            .apply(vec![crate::editor::Effect::Replace(
+                "\t界e\u{301}  \n\n".into(),
+            )])
             .unwrap();
         editor.handle(Input::Char('V'));
         editor.handle(Input::Down);
         editor.handle(Input::Down);
         let before = (editor.lines().to_vec(), editor.cursor(), editor.carets());
-        for width in [12, 3, 1] {
+        for width in [16, 3, 1] {
             let mut terminal = Terminal::new(ratatui::backend::TestBackend::new(width, 6)).unwrap();
             let (mut top, mut left) = (0, 0);
-            terminal
+            let frame = terminal
                 .draw(|frame| {
                     draw(
                         frame,
@@ -5593,8 +5599,8 @@ end
                     )
                 })
                 .unwrap();
-            let buffer = terminal.backend().buffer();
-            if width == 12 {
+            let buffer = frame.buffer;
+            if width == 16 {
                 let status: String = (0..width).map(|x| buffer[(x, 4)].symbol()).collect();
                 assert!(status.contains("VISUAL LINE"), "{status}");
             }
@@ -5603,8 +5609,17 @@ end
                 for x in 0..gutter {
                     assert_ne!(buffer[(x, row)].bg, Color::Blue);
                 }
+                let selected_width = if row == 0 { 10 } else { 1 };
                 for x in gutter..width {
-                    assert_eq!(buffer[(x, row)].bg, Color::Blue);
+                    if x - gutter < selected_width {
+                        assert_eq!(
+                            buffer[(x, row)].bg,
+                            Color::Blue,
+                            "width {width}, row {row}, x {x}"
+                        );
+                    } else {
+                        assert_ne!(buffer[(x, row)].bg, Color::Blue);
+                    }
                 }
             }
             for x in 0..width {