Hi Thomas, Thanks so much for all of your suggestions and for explaining the extra DIVs, it makes a lot more sense now. I'll try what you said and let you know. Thanks again.
-Seth On Friday, March 30, 2012 5:40:47 AM UTC-4, Thomas Broyer wrote: > > > > On Thursday, March 29, 2012 5:43:55 AM UTC+2, GWTter wrote: >> >> Hi all, >> >> I've used the CustomScrollPanel in order to implement some custom >> scrollbars, everything was working great until I added DnD (gwt-dnd, not >> native) functionality >> to an element in the scrollpanel. The dragging action on the elements >> within is extremely laggy. After a good amount of testing I found that the >> issue had to do with >> the CustomScrollPanel since using a regular ScrollPanel performs just >> fine with minimal lag if any. I then looked at what is generated for the >> customscrollpanel to >> work and found some divs had been generated which I couldn't attribute >> any specific functionality to (ITEMs 1 & 2 below). They're basically just >> overlaying the whole >> scrollpanel area and deleting them with firebug did not affect the >> customscrollpanel functionality, but deleting them did improve the dnd >> performance considerably. I see that >> the more elements that are layered between the mouse click and the target >> element affect the performance to a good degree. >> >> My question is does anyone know if these extra DIVs are needed, and if so >> is there a way to workaround so I can still have the custom scroll bars >> with good DnD. >> > > The DIVs are added by the ResizeLayoutPanel.ImplStandard to detect when > the content grows or shrinks, so the CustomScrollPanel can update the > scrollbars. > > BTW, the ITEM3 div is used by the Layout to detect changes of the font > size so ti can update its layers when they're positioned using EM or EX > units. > > Does changing the z-index of the various divs (ITEM1, ITEM2 and > dragdrop-dropTarget) changes anything performance-wise? > > DIRTY HACK: You could also try calling onDetach() on the > containerResizeImpl when entering the scroll panel (while dragging) and > calling onAttach() when leaving or dropping (use JSNI to access the private > containerResizeImpl). You might have to explicitly call > maybeUpdateScrollbars() after calling containerResizeImpl.onAttach(), as > I'm not sure onAttach() would call the ResizeLayoutPanel.Impl.Delegate), > and you might have to call it from a Scheduler.get().scheduleDeferred(), as > ResizeLayoutPanel.ImplStandard uses it. > -- You received this message because you are subscribed to the Google Groups "Google Web Toolkit" group. To view this discussion on the web visit https://groups.google.com/d/msg/google-web-toolkit/-/rs-N4h0_ED4J. To post to this group, send email to google-web-toolkit@googlegroups.com. To unsubscribe from this group, send email to google-web-toolkit+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/google-web-toolkit?hl=en.
