Ticket #284: menu-diagonal-movement.patch

src/kits/interface/Menu.cpp

@@ -1394 +1394 @@
 {
     // TODO: cleanup
     BMenuItem *item = NULL;
-    bigtime_t openTime = system_time();
-    
+    BRect navAreaRectAbove, navAreaRectBelow;
+
     fState = MENU_STATE_TRACKING;
     if (fSuper != NULL)
         fSuper->fState = MENU_STATE_TRACKING_SUBMENU;
@@ -1432 +1432 @@
         bool overSub = _OverSubmenu(fSelected, screenLocation);
         item = _HitTestItems(location, B_ORIGIN);
         if (overSub) {
+            navAreaRectAbove = BRect();
+            navAreaRectBelow = BRect();
+
             // Since the submenu has its own looper,
             // we can unlock ours. Doing so also make sure
             // that our window gets any update message to
@@ -1453 +1456 @@
             if (!LockLooper())
                 break;          
         } else if (item != NULL) {
-            _UpdateStateOpenSelect(item, openTime, mouseSpeed);
+            _UpdateStateOpenSelect(item, location, navAreaRectAbove, navAreaRectBelow);
             if (!releasedOnce)
                 releasedOnce = true;        
         } else if (_OverSuper(screenLocation)) {
@@ -1528 +1531 @@
 
 
 void
-BMenu::_UpdateStateOpenSelect(BMenuItem* item, bigtime_t& openTime,
-    const int32 &mouseSpeed)
+BMenu::_UpdateNavigationArea(BPoint position, BRect& navAreaRectAbove,
+    BRect& navAreaRectBelow)
 {
+#define NAV_AREA_THRESHOLD    3
+
+    // The navigation area is a region in which mouse-overs won't select
+    // the item under the cursor. This makes it easier to navigate to
+    // submenus, as the cursor can be moved to submenu items directly instead
+    // of having to move it horizontally into the submenu first. The concept
+    // is illustrated below:
+    // 
+    // +-------+----+---------+
+    // |       |   /|         |
+    // |       |  /*|         |
+    // |[2]--> | /**|         |
+    // |       |/[4]|         |
+    // |------------|         |
+    // |    [1]     |   [6]   |
+    // |------------|         |
+    // |       |\[5]|         |
+    // |[3]--> | \**|         |
+    // |       |  \*|         |
+    // |       |   \|         |
+    // |       +----|---------+
+    // |            |
+    // +------------+
+    //
+    // [1] Selected item, cursor position ('position')
+    // [2] Upper navigation area rectangle ('navAreaRectAbove')
+    // [3] Lower navigation area rectangle ('navAreaRectBelow')
+    // [4] Upper navigation area
+    // [5] Lower navigation area
+    // [6] Submenu  
+    //
+    // The rectangles are used to calculate if the cursor is in the actual
+    // navigation area (see _UpdateStateOpenSelect()).
+
+    if (fSelected == NULL)
+        return;
+
+    BMenu *submenu = fSelected->Submenu();
+
+    if (submenu != NULL) {
+        BRect menuBounds = fSelected->Menu()->ConvertToScreen(
+            fSelected->Menu()->Bounds());
+
+        fSelected->Submenu()->LockLooper();
+        BRect submenuBounds = fSelected->Submenu()->ConvertToScreen(
+            fSelected->Submenu()->Bounds());
+        fSelected->Submenu()->UnlockLooper();
+
+        if (menuBounds.left < submenuBounds.left) {
+            navAreaRectAbove.Set(position.x + NAV_AREA_THRESHOLD,
+                submenuBounds.top, menuBounds.right,
+                position.y);
+            navAreaRectBelow.Set(position.x + NAV_AREA_THRESHOLD,
+                position.y, menuBounds.right,
+                submenuBounds.bottom);
+        } else {
+            navAreaRectAbove.Set(menuBounds.left,
+                submenuBounds.top, position.x - NAV_AREA_THRESHOLD,
+                position.y);
+            navAreaRectBelow.Set(menuBounds.left,
+                position.y, position.x - NAV_AREA_THRESHOLD,
+                submenuBounds.bottom);
+        }
+    } else {
+        navAreaRectAbove = BRect();
+        navAreaRectBelow = BRect();
+    }
+}
+
+void
+BMenu::_UpdateStateOpenSelect(BMenuItem* item, BPoint position,
+    BRect& navAreaRectAbove, BRect& navAreaRectBelow)
+{
     if (fState == MENU_STATE_CLOSED)
         return;
 
     if (item != fSelected) {
-        if (mouseSpeed < kMouseMotionThreshold) {       
-            _SelectItem(item, false);
-            openTime = system_time();
+        position = ConvertToScreen(position);
+
+        bool inNavAreaRectAbove = navAreaRectAbove.Contains(position);
+        bool inNavAreaRectBelow = navAreaRectBelow.Contains(position);
+
+        if (!inNavAreaRectAbove && !inNavAreaRectBelow) {
+            _SelectItem(item);
+            _UpdateNavigationArea(position, navAreaRectAbove, navAreaRectBelow);
+            return;
+        }
+
+        BRect menuBounds = fSelected->Menu()->ConvertToScreen(
+            fSelected->Menu()->Bounds());
+
+        fSelected->Submenu()->LockLooper();
+        BRect submenuBounds = fSelected->Submenu()->ConvertToScreen(
+            fSelected->Submenu()->Bounds());
+        fSelected->Submenu()->UnlockLooper();
+
+        float x_offset;
+
+        // navAreaRectAbove and navAreaRectBelow have the same X
+        // position and width, so it doesn't matter which one we use to
+        // calculate the X offset
+        if (menuBounds.left < submenuBounds.left)
+            x_offset = position.x - navAreaRectAbove.left;
+        else
+            x_offset = navAreaRectAbove.right - position.x;
+
+        bool inNavArea;
+
+        if (inNavAreaRectAbove) {
+            float y_offset = navAreaRectAbove.bottom - position.y;
+            float ratio = navAreaRectAbove.Width() / navAreaRectAbove.Height();
+
+            inNavArea = y_offset <= x_offset / ratio;
         } else {
-            //printf("Mouse moving too fast (%ld), ignoring...\n", mouseSpeed);     
+            float y_offset = navAreaRectBelow.bottom - position.y;
+            float ratio = navAreaRectBelow.Width() / navAreaRectBelow.Height();
+
+            inNavArea = y_offset >= (navAreaRectBelow.Height() - x_offset / ratio);
         }
-    } else if (system_time() > kHysteresis + openTime && item->Submenu() != NULL
-        && item->Submenu()->Window() == NULL) {
-        // Open the submenu if it's not opened yet, but only if
-        // the mouse pointer stayed over there for some time
-        // (hysteresis)
-        _SelectItem(item);
+
+        if (!inNavArea) {
+            _SelectItem(item);
+            _UpdateNavigationArea(position, navAreaRectAbove, navAreaRectBelow);
+        }
     }
     if (fState != MENU_STATE_TRACKING)
         fState = MENU_STATE_TRACKING;