fix: limit row and column selection borders

Author: uednd

src/widget/table/draw.rs

@@ -1,6 +1,6 @@
 use ratatui::{buffer::Buffer, layout::Rect, style::Style};
 
-use super::primitives::{BorderStroke, CellRect, RegionRect};
+use super::primitives::{BorderSides, BorderStroke, CellRect, RegionRect};
 
 pub fn draw_cell_border(buffer: &mut Buffer, cell_rect: CellRect, style: Style) {
     let CellRect {
@@ -24,11 +24,12 @@ pub fn draw_cell_border(buffer: &mut Buffer, cell_rect: CellRect, style: Style)
     buffer[(right, content)].set_symbol("┃").set_style(style);
 }
 
-pub fn draw_region_border(
+pub fn draw_region_border_sides(
     buffer: &mut Buffer,
     region: RegionRect,
     style: Style,
     stroke: BorderStroke,
+    sides: BorderSides,
 ) {
     let glyphs = stroke.glyphs();
     let RegionRect {
@@ -38,33 +39,53 @@ pub fn draw_region_border(
         bottom_y: bottom,
     } = region;
 
-    buffer[(left, top)]
-        .set_symbol(glyphs.top_left)
-        .set_style(style);
-    buffer[(right, top)]
-        .set_symbol(glyphs.top_right)
-        .set_style(style);
-    buffer[(left, bottom)]
-        .set_symbol(glyphs.bottom_left)
-        .set_style(style);
-    buffer[(right, bottom)]
-        .set_symbol(glyphs.bottom_right)
-        .set_style(style);
+    if sides.top {
+        for x in left..=right {
+            buffer[(x, top)]
+                .set_symbol(glyphs.horizontal)
+                .set_style(style);
+        }
+    }
+    if sides.bottom {
+        for x in left..=right {
+            buffer[(x, bottom)]
+                .set_symbol(glyphs.horizontal)
+                .set_style(style);
+        }
+    }
+    if sides.left {
+        for y in top..=bottom {
+            buffer[(left, y)]
+                .set_symbol(glyphs.vertical)
+                .set_style(style);
+        }
+    }
+    if sides.right {
+        for y in top..=bottom {
+            buffer[(right, y)]
+                .set_symbol(glyphs.vertical)
+                .set_style(style);
+        }
+    }
 
-    for x in left + 1..right {
-        buffer[(x, top)]
-            .set_symbol(glyphs.horizontal)
+    if sides.top && sides.left {
+        buffer[(left, top)]
+            .set_symbol(glyphs.top_left)
             .set_style(style);
-        buffer[(x, bottom)]
-            .set_symbol(glyphs.horizontal)
+    }
+    if sides.top && sides.right {
+        buffer[(right, top)]
+            .set_symbol(glyphs.top_right)
             .set_style(style);
     }
-    for y in top + 1..bottom {
-        buffer[(left, y)]
-            .set_symbol(glyphs.vertical)
+    if sides.bottom && sides.left {
+        buffer[(left, bottom)]
+            .set_symbol(glyphs.bottom_left)
             .set_style(style);
-        buffer[(right, y)]
-            .set_symbol(glyphs.vertical)
+    }
+    if sides.bottom && sides.right {
+        buffer[(right, bottom)]
+            .set_symbol(glyphs.bottom_right)
             .set_style(style);
     }
 }

src/widget/table/mod.rs

@@ -15,7 +15,7 @@ use crate::{model::cell::col_name, theme::Theme};
 
 use self::{
     layout::GridLayout,
-    primitives::{BorderStroke, CellRect, RegionRect},
+    primitives::{BorderSides, BorderStroke, CellRect, RegionRect},
     view::{GridScroll, GridSelection},
 };
 
@@ -130,11 +130,12 @@ impl TableGrid {
             && let Some(region) =
                 selection_to_region_rect(&cfg.layout, &sc, &sel, rendered_rows, rendered_cols)
         {
-            draw::draw_region_border(
+            draw::draw_region_border_sides(
                 buffer,
                 region,
                 Style::default().fg(cfg.theme.accent),
                 BorderStroke::Solid,
+                selection_border_sides(&sel),
             );
         }
 
@@ -143,11 +144,12 @@ impl TableGrid {
             && let Some(rect) =
                 selection_to_region_rect(&cfg.layout, &sc, &region, rendered_rows, rendered_cols)
         {
-            draw::draw_region_border(
+            draw::draw_region_border_sides(
                 buffer,
                 rect,
                 Style::default().fg(cfg.theme.accent),
                 BorderStroke::Dashed,
+                selection_border_sides(&region),
             );
         }
 
@@ -179,6 +181,14 @@ fn cursor_cell_rect(
     layout.cell_rect(vis_row, vis_col)
 }
 
+fn selection_border_sides(selection: &GridSelection) -> BorderSides {
+    match selection {
+        GridSelection::Row(_) => BorderSides::HORIZONTAL,
+        GridSelection::Column(_) => BorderSides::VERTICAL,
+        GridSelection::Range { .. } => BorderSides::ALL,
+    }
+}
+
 fn selection_to_region_rect(
     layout: &GridLayout,
     scroll: &GridScroll,
@@ -225,3 +235,76 @@ fn selection_to_region_rect(
         }
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use ratatui::{Terminal, backend::TestBackend, layout::Rect};
+
+    use super::{
+        TableGrid, TableGridConfig,
+        layout::GridMetrics,
+        view::{GridScroll, GridSelection},
+    };
+    use crate::{model::cell::CellAddress, theme::Theme};
+
+    fn render_selection(selection: GridSelection) -> ratatui::buffer::Buffer {
+        let backend = TestBackend::new(40, 10);
+        let mut terminal = Terminal::new(backend).unwrap();
+        let theme = Theme::dark();
+        let cell_text = |_: usize, _: usize| String::new();
+
+        let frame = terminal
+            .draw(|frame| {
+                let area = Rect::new(0, 0, 40, 10);
+                let layout = GridMetrics::new(8, 4, 2).layout(area);
+                TableGrid::render(
+                    frame,
+                    frame.area(),
+                    TableGridConfig {
+                        scroll: GridScroll {
+                            scroll_row: 0,
+                            scroll_col: 0,
+                            visible_rows: 3,
+                            visible_cols: 3,
+                            cursor: CellAddress { row: 1, col: 1 },
+                            total_rows: 3,
+                            total_cols: 3,
+                        },
+                        layout,
+                        theme,
+                        blink_visible: true,
+                        edit_buffer: None,
+                        selection: Some(selection),
+                        copied_region: None,
+                        cell_text: &cell_text,
+                    },
+                );
+            })
+            .unwrap();
+
+        frame.buffer.clone()
+    }
+
+    #[test]
+    fn column_selection_draws_only_left_and_right_edges() {
+        let buffer = render_selection(GridSelection::Column(1));
+        let accent = Theme::dark().accent;
+
+        assert_eq!(buffer[(13, 1)].fg, accent);
+        assert_eq!(buffer[(22, 1)].fg, accent);
+        assert_ne!(buffer[(14, 0)].symbol(), "━");
+        assert_ne!(buffer[(14, 7)].symbol(), "━");
+        assert_ne!(buffer[(14, 7)].fg, accent);
+    }
+
+    #[test]
+    fn row_selection_draws_only_top_and_bottom_edges() {
+        let buffer = render_selection(GridSelection::Row(1));
+        let accent = Theme::dark().accent;
+
+        assert_eq!(buffer[(14, 3)].fg, accent);
+        assert_eq!(buffer[(14, 5)].fg, accent);
+        assert_ne!(buffer[(4, 4)].fg, accent);
+        assert_ne!(buffer[(31, 4)].fg, accent);
+    }
+}

src/widget/table/primitives.rs

@@ -27,6 +27,37 @@ pub enum BorderStroke {
     Dashed,
 }
 
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub struct BorderSides {
+    pub top: bool,
+    pub right: bool,
+    pub bottom: bool,
+    pub left: bool,
+}
+
+impl BorderSides {
+    pub const ALL: Self = Self {
+        top: true,
+        right: true,
+        bottom: true,
+        left: true,
+    };
+
+    pub const HORIZONTAL: Self = Self {
+        top: true,
+        right: false,
+        bottom: true,
+        left: false,
+    };
+
+    pub const VERTICAL: Self = Self {
+        top: false,
+        right: true,
+        bottom: false,
+        left: true,
+    };
+}
+
 #[derive(Debug, Clone, Copy)]
 pub(crate) struct BorderGlyphs {
     pub horizontal: &'static str,