patch by Andrea Anzani (with a few style modification by me) which

enables tab (as BTab) switching via mouse wheel. Thanks!
 


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@24214 a95241bf-73f2-0310-859d-f6bbb57e9c96

src/kits/interface/TabView.cpp

@@ -508,7 +508,10 @@ BTabView::DetachedFromWindow()
 void
 BTabView::MessageReceived(BMessage *message)
 {
-	if (message->what == B_GET_PROPERTY || message->what == B_SET_PROPERTY) {
+	switch (message->what) {
+		case B_GET_PROPERTY:
+		case B_SET_PROPERTY:
+		{
 			BMessage reply(B_REPLY);
 			bool handled = false;
 
@@ -533,12 +536,40 @@ BTabView::MessageReceived(BMessage *message)
 				}
 			}
 			
-		if (handled) {
+			if (handled)
 				message->SendReply(&reply);
-			return;
+			else
-		}
-	}
 				BView::MessageReceived(message);
+			break;
+		}
+		
+		case B_MOUSE_WHEEL_CHANGED:
+		{
+			float deltaX = 0.0f;
+			float deltaY = 0.0f;
+			message->FindFloat("be:wheel_delta_x", &deltaX);
+			message->FindFloat("be:wheel_delta_y", &deltaY);
+			
+			if (deltaX == 0.0f && deltaY == 0.0f)
+				return;
+			
+			if (deltaY == 0.0f)
+				deltaY = deltaX;
+				
+			int32 selection = Selection();
+			int32 numTabs = CountTabs();
+			if (deltaY > 0  && selection < numTabs - 1) {
+				//move to the right tab.
+				Select(Selection() + 1);
+			} else if (deltaY < 0 && selection > 0 && numTabs > 1) {
+				//move to the left tab.
+				Select(selection - 1);
+			}
+		}
+		default:
+			BView::MessageReceived(message);
+			break;	
+	}
 }