window: add cursors for resizing up/down left/right

Change the cursor to an appropriate one of these when hoving
over and dragging a split.

Fix an issue where we wouldn't always change the cursor when
hovering over a split when multiple splits are present.

wezterm/src/gui/termwindow.rs

@@ -3303,7 +3303,7 @@ impl TermWindow {
         event: &MouseEvent,
         context: &dyn WindowOps,
     ) {
-        let mut on_split = false;
+        let mut on_split = None;
         if y >= 0 {
             let y = y as usize;
 
@@ -3311,24 +3311,30 @@ impl TermWindow {
                 on_split = match split.direction {
                     SplitDirection::Horizontal => {
                         if x == split.left && y >= split.top && y <= split.top + split.size {
-                            true
+                            Some(SplitDirection::Horizontal)
                         } else {
-                            false
+                            None
                         }
                     }
                     SplitDirection::Vertical => {
                         if y == split.top && x >= split.left && x <= split.left + split.size {
-                            true
+                            Some(SplitDirection::Vertical)
                         } else {
-                            false
+                            None
                         }
                     }
                 };
 
-                if on_split && event.kind == WMEK::Press(MousePress::Left) {
-                    context.set_cursor(Some(MouseCursor::Hand));
-                    self.split_drag_start.replace(split);
-                    return;
+                if on_split.is_some() {
+                    if event.kind == WMEK::Press(MousePress::Left) {
+                        context.set_cursor(on_split.map(|d| match d {
+                            SplitDirection::Horizontal => MouseCursor::SizeLeftRight,
+                            SplitDirection::Vertical => MouseCursor::SizeUpDown,
+                        }));
+                        self.split_drag_start.replace(split);
+                        return;
+                    }
+                    break;
                 }
             }
         }
@@ -3396,12 +3402,18 @@ impl TermWindow {
             }
         };
 
-        context.set_cursor(Some(if on_split || self.current_highlight.is_some() {
-            // When hovering over a hyperlink, show an appropriate
-            // mouse cursor to give the cue that it is clickable
-            MouseCursor::Hand
-        } else {
-            MouseCursor::Text
+        context.set_cursor(Some(match on_split {
+            Some(SplitDirection::Horizontal) => MouseCursor::SizeLeftRight,
+            Some(SplitDirection::Vertical) => MouseCursor::SizeUpDown,
+            None => {
+                if self.current_highlight.is_some() {
+                    // When hovering over a hyperlink, show an appropriate
+                    // mouse cursor to give the cue that it is clickable
+                    MouseCursor::Hand
+                } else {
+                    MouseCursor::Text
+                }
+            }
         }));
 
         let event_trigger_type = match &event.kind {

window/src/lib.rs

@@ -105,6 +105,8 @@ pub enum MouseCursor {
     Arrow,
     Hand,
     Text,
+    SizeUpDown,
+    SizeLeftRight,
 }
 
 #[allow(unused_variables)]

window/src/os/macos/window.rs

@@ -653,6 +653,8 @@ impl WindowOpsMut for WindowInner {
                     MouseCursor::Arrow => msg_send![ns_cursor_cls, arrowCursor],
                     MouseCursor::Text => msg_send![ns_cursor_cls, IBeamCursor],
                     MouseCursor::Hand => msg_send![ns_cursor_cls, pointingHandCursor],
+                    MouseCursor::SizeUpDown => msg_send![ns_cursor_cls, resizeUpDown],
+                    MouseCursor::SizeLeftRight => msg_send![ns_cursor_cls, resizeLeftRight],
                 };
                 let () = msg_send![instance, set];
             }

window/src/os/wayland/window.rs

@@ -929,6 +929,8 @@ impl WindowOpsMut for WaylandWindowInner {
         let cursor = match cursor {
             Some(MouseCursor::Arrow) => "arrow",
             Some(MouseCursor::Hand) => "hand",
+            Some(MouseCursor::SizeUpDown) => "ns-resize",
+            Some(MouseCursor::SizeLeftRight) => "ew-resize",
             Some(MouseCursor::Text) => "text",
             None => return,
         };

window/src/os/windows/window.rs

@@ -885,6 +885,8 @@ fn apply_mouse_cursor(cursor: Option<MouseCursor>) {
                     MouseCursor::Arrow => IDC_ARROW,
                     MouseCursor::Hand => IDC_HAND,
                     MouseCursor::Text => IDC_IBEAM,
+                    MouseCursor::SizeUpDown => IDC_SIZENS,
+                    MouseCursor::SizeLeftRight => IDC_SIZEWE,
                 },
             ));
         },

window/src/os/x11/window.rs

@@ -288,6 +288,8 @@ impl XWindowInner {
                     MouseCursor::Arrow => 132,
                     MouseCursor::Hand => 58,
                     MouseCursor::Text => 152,
+                    MouseCursor::SizeUpDown => 116,
+                    MouseCursor::SizeLeftRight => 108,
                 };
 
                 let cursor_id: xcb::ffi::xcb_cursor_t = conn.generate_id();