macOS: simple SplitView AX

Proper labels, action to move the divider

macos/Sources/Features/Splits/SplitView.Divider.swift

@@ -7,6 +7,7 @@ extension SplitView {
         let visibleSize: CGFloat
         let invisibleSize: CGFloat
         let color: Color
+        @Binding var split: CGFloat
 
         private var visibleWidth: CGFloat? {
             switch (direction) {
@@ -79,6 +80,40 @@ extension SplitView {
                     NSCursor.pop()
                 }
             }
+            .accessibilityElement(children: .ignore)
+            .accessibilityLabel(axLabel)
+            .accessibilityValue("\(Int(split * 100))%")
+            .accessibilityHint(axHint)
+            .accessibilityAddTraits(.isButton)
+            .accessibilityAdjustableAction { direction in
+                let adjustment: CGFloat = 0.025
+                switch direction {
+                case .increment:
+                    split = min(split + adjustment, 0.9)
+                case .decrement:
+                    split = max(split - adjustment, 0.1)
+                @unknown default:
+                    break
+                }
+            }
+        }
+
+        private var axLabel: String {
+            switch direction {
+            case .horizontal:
+                return "Horizontal split divider"
+            case .vertical:
+                return "Vertical split divider"
+            }
+        }
+
+        private var axHint: String {
+            switch direction {
+            case .horizontal:
+                return "Drag to resize the left and right panes"
+            case .vertical:
+                return "Drag to resize the top and bottom panes"
+            }
         }
     }
 }

macos/Sources/Features/Splits/SplitView.swift

@@ -42,16 +42,23 @@ struct SplitView<L: View, R: View>: View {
                 left
                     .frame(width: leftRect.size.width, height: leftRect.size.height)
                     .offset(x: leftRect.origin.x, y: leftRect.origin.y)
+                    .accessibilityElement(children: .contain)
+                    .accessibilityLabel(leftPaneLabel)
                 right
                     .frame(width: rightRect.size.width, height: rightRect.size.height)
                     .offset(x: rightRect.origin.x, y: rightRect.origin.y)
+                    .accessibilityElement(children: .contain)
+                    .accessibilityLabel(rightPaneLabel)
                 Divider(direction: direction,
                         visibleSize: splitterVisibleSize,
                         invisibleSize: splitterInvisibleSize,
-                        color: dividerColor)
+                        color: dividerColor,
+                        split: $split)
                     .position(splitterPoint)
                     .gesture(dragGesture(geo.size, splitterPoint: splitterPoint))
             }
+            .accessibilityElement(children: .contain)
+            .accessibilityLabel(splitViewLabel)
         }
     }
 
@@ -137,6 +144,35 @@ struct SplitView<L: View, R: View>: View {
             return CGPoint(x: size.width / 2, y: leftRect.size.height)
         }
     }
+    
+    // MARK: Accessibility
+    
+    private var splitViewLabel: String {
+        switch direction {
+        case .horizontal:
+            return "Horizontal split view"
+        case .vertical:
+            return "Vertical split view"
+        }
+    }
+    
+    private var leftPaneLabel: String {
+        switch direction {
+        case .horizontal:
+            return "Left pane"
+        case .vertical:
+            return "Top pane"
+        }
+    }
+    
+    private var rightPaneLabel: String {
+        switch direction {
+        case .horizontal:
+            return "Right pane"
+        case .vertical:
+            return "Bottom pane"
+        }
+    }
 }
 
 enum SplitViewDirection: Codable {

macos/Sources/Features/Splits/TerminalSplitTreeView.swift

@@ -32,6 +32,8 @@ struct TerminalSplitSubtreeView: View {
             Ghostty.InspectableSurface(
                 surfaceView: leafView,
                 isSplit: !isRoot)
+                .accessibilityElement(children: .contain)
+                .accessibilityLabel("Terminal pane")
 
         case .split(let split):
             let splitViewDirection: SplitViewDirection = switch (split.direction) {