fix: add configurable pane gaps

refs #271

1 files changed, 142 insertions, 10 deletions

diff --git a/src/app/input/mouse.rs b/src/app/input/mouse.rs
index 41bb5267..c8a03674 100644
--- a/src/app/input/mouse.rs
+++ b/src/app/input/mouse.rs
@@ -393,11 +393,16 @@ impl AppState {
 
                 if !in_sidebar {
                     if let Some(border) = self.find_border_at(mouse.column, mouse.row) {
+                        let grab_offset = match border.direction {
+                            Direction::Horizontal => border.pos.saturating_sub(mouse.column),
+                            Direction::Vertical => border.pos.saturating_sub(mouse.row),
+                        };
                         self.drag = Some(DragState {
                             target: DragTarget::PaneSplit {
                                 path: border.path.clone(),
                                 direction: border.direction,
                                 area: border.area,
+                                grab_offset,
                             },
                         });
                         return None;
@@ -694,14 +699,23 @@ impl AppState {
                             path,
                             direction,
                             area,
+                            grab_offset,
                         } => {
                             let ratio = match direction {
                                 Direction::Horizontal => {
-                                    (mouse.column.saturating_sub(area.x)) as f32
+                                    (mouse
+                                        .column
+                                        .saturating_add(*grab_offset)
+                                        .saturating_sub(area.x))
+                                        as f32
                                         / area.width.max(1) as f32
                                 }
                                 Direction::Vertical => {
-                                    (mouse.row.saturating_sub(area.y)) as f32
+                                    (mouse
+                                        .row
+                                        .saturating_add(*grab_offset)
+                                        .saturating_sub(area.y))
+                                        as f32
                                         / area.height.max(1) as f32
                                 }
                             };
@@ -1257,18 +1271,39 @@ impl AppState {
 
     pub(super) fn find_border_at(&self, col: u16, row: u16) -> Option<&SplitBorder> {
         self.view.split_borders.iter().find(|b| match b.direction {
-            Direction::Horizontal => {
-                col >= b.pos.saturating_sub(1)
+            Direction::Horizontal if self.pane_borders && !self.pane_gaps => {
+                col == b.pos && row >= b.area.y && row < b.area.y + b.area.height
+            }
+            Direction::Horizontal if self.pane_borders && self.pane_gaps => {
+                row >= b.area.y
+                    && row < b.area.y + b.area.height
+                    && col >= b.pos.saturating_sub(1)
                     && col <= b.pos
-                    && row >= b.area.y
+            }
+            Direction::Horizontal if !self.pane_borders && self.pane_gaps => {
+                row >= b.area.y
                     && row < b.area.y + b.area.height
+                    && b.pos.checked_sub(1).is_some_and(|gap_col| {
+                        col == gap_col && self.pane_frame_at(col, row).is_none()
+                    })
+            }
+            Direction::Vertical if self.pane_borders && !self.pane_gaps => {
+                row == b.pos && col >= b.area.x && col < b.area.x + b.area.width
             }
-            Direction::Vertical => {
-                row >= b.pos.saturating_sub(1)
+            Direction::Vertical if self.pane_borders && self.pane_gaps => {
+                col >= b.area.x
+                    && col < b.area.x + b.area.width
+                    && row >= b.pos.saturating_sub(1)
                     && row <= b.pos
-                    && col >= b.area.x
+            }
+            Direction::Vertical if !self.pane_borders && self.pane_gaps => {
+                col >= b.area.x
                     && col < b.area.x + b.area.width
+                    && b.pos.checked_sub(1).is_some_and(|gap_row| {
+                        row == gap_row && self.pane_frame_at(col, row).is_none()
+                    })
             }
+            _ => false,
         })
     }
 
@@ -2612,6 +2647,7 @@ mod tests {
         app.state.workspaces = vec![Workspace::test_new("test")];
         app.state.active = Some(0);
         app.state.selected = 0;
+        app.state.pane_gaps = false;
         app.state.workspaces[0].test_split(Direction::Horizontal);
         crate::ui::compute_view(&mut app.state, Rect::new(0, 0, 106, 20));
         let border = app.state.view.split_borders[0].clone();
@@ -2620,7 +2656,7 @@ mod tests {
         assert!(app
             .state
             .find_border_at(border.pos.saturating_sub(1), row)
-            .is_some());
+            .is_none());
         assert!(app.state.find_border_at(border.pos, row).is_some());
         assert!(app
             .state
@@ -2634,6 +2670,7 @@ mod tests {
         app.state.workspaces = vec![Workspace::test_new("test")];
         app.state.active = Some(0);
         app.state.selected = 0;
+        app.state.pane_gaps = false;
         app.state.workspaces[0].test_split(Direction::Vertical);
         crate::ui::compute_view(&mut app.state, Rect::new(0, 0, 106, 20));
         let border = app.state.view.split_borders[0].clone();
@@ -2642,7 +2679,7 @@ mod tests {
         assert!(app
             .state
             .find_border_at(col, border.pos.saturating_sub(1))
-            .is_some());
+            .is_none());
         assert!(app.state.find_border_at(col, border.pos).is_some());
         assert!(app
             .state
@@ -2651,6 +2688,101 @@ mod tests {
     }
 
     #[test]
+    fn borderless_no_gap_split_has_no_mouse_hitbox_over_content() {
+        let mut app = app_for_mouse_test();
+        app.state.workspaces = vec![Workspace::test_new("test")];
+        app.state.active = Some(0);
+        app.state.selected = 0;
+        app.state.pane_borders = false;
+        app.state.workspaces[0].test_split(Direction::Horizontal);
+        crate::ui::compute_view(&mut app.state, Rect::new(0, 0, 106, 20));
+        let border = app.state.view.split_borders[0].clone();
+        let row = border.area.y.saturating_add(1);
+
+        assert!(app.state.find_border_at(border.pos, row).is_none());
+    }
+
+    #[test]
+    fn bordered_pane_gaps_keep_both_split_borders_draggable() {
+        let mut app = app_for_mouse_test();
+        app.state.workspaces = vec![Workspace::test_new("test")];
+        app.state.active = Some(0);
+        app.state.selected = 0;
+        app.state.pane_gaps = true;
+        app.state.workspaces[0].test_split(Direction::Horizontal);
+        crate::ui::compute_view(&mut app.state, Rect::new(0, 0, 106, 20));
+        let border = app.state.view.split_borders[0].clone();
+        let row = border.area.y.saturating_add(1);
+
+        assert!(app
+            .state
+            .find_border_at(border.pos.saturating_sub(1), row)
+            .is_some());
+        assert!(app.state.find_border_at(border.pos, row).is_some());
+        assert!(app
+            .state
+            .find_border_at(border.pos.saturating_add(1), row)
+            .is_none());
+    }
+
+    #[test]
+    fn borderless_pane_gap_is_not_a_pane_but_remains_split_draggable() {
+        let mut app = app_for_mouse_test();
+        app.state.workspaces = vec![Workspace::test_new("test")];
+        app.state.active = Some(0);
+        app.state.selected = 0;
+        app.state.pane_borders = false;
+        app.state.pane_gaps = true;
+        app.state.workspaces[0].test_split(Direction::Horizontal);
+        crate::ui::compute_view(&mut app.state, Rect::new(0, 0, 106, 20));
+        let border = app.state.view.split_borders[0].clone();
+        let row = border.area.y.saturating_add(1);
+        let gap_col = border.pos.saturating_sub(1);
+
+        assert!(app.state.pane_at(gap_col, row).is_none());
+        assert!(app.state.find_border_at(gap_col, row).is_some());
+        assert!(app.state.find_border_at(border.pos, row).is_none());
+    }
+
+    #[test]
+    fn borderless_gap_hitbox_is_empty_when_first_split_side_has_one_cell() {
+        let mut app = app_for_mouse_test();
+        app.state.workspaces = vec![Workspace::test_new("test")];
+        app.state.active = Some(0);
+        app.state.selected = 0;
+        app.state.pane_borders = false;
+        app.state.pane_gaps = true;
+        app.state.workspaces[0].test_split(Direction::Horizontal);
+        crate::ui::compute_view(&mut app.state, Rect::new(0, 0, 2, 4));
+        let border = app.state.view.split_borders[0].clone();
+        let row = border.area.y.saturating_add(1);
+        let candidate_gap_col = border.pos.saturating_sub(1);
+
+        assert!(app.state.pane_frame_at(candidate_gap_col, row).is_some());
+        assert!(app.state.find_border_at(candidate_gap_col, row).is_none());
+    }
+
+    #[test]
+    fn borderless_gap_hitbox_is_empty_when_first_split_side_has_zero_width() {
+        let mut app = app_for_mouse_test();
+        app.state.workspaces = vec![Workspace::test_new("test")];
+        app.state.active = Some(0);
+        app.state.selected = 0;
+        app.state.pane_borders = false;
+        app.state.pane_gaps = true;
+        app.state.workspaces[0].test_split(Direction::Horizontal);
+        app.state.workspaces[0].tabs[0]
+            .layout
+            .set_ratio_at(&[], 0.1);
+        crate::ui::compute_view(&mut app.state, Rect::new(0, 0, 1, 4));
+        let border = app.state.view.split_borders[0].clone();
+        let row = border.area.y.saturating_add(1);
+
+        assert_eq!(border.pos, 0);
+        assert!(app.state.find_border_at(0, row).is_none());
+    }
+
+    #[test]
     fn selecting_from_right_pane_first_content_column_starts_selection() {
         let mut app = app_for_mouse_test();
         let mut ws = Workspace::test_new("test");