I like this kind of being wrong :-) Tomas
On Fri, Aug 15, 2014 at 12:42 AM, Jonathan Giles <jonathan.gi...@oracle.com> wrote: > Actually this is slightly wrong. I was holding off replying until I had a > bit more time to be thorough, but I'll respond now to prevent this > misunderstanding from being discussed :-) > > It _is_ possible to virtualise the TableView in both directions. This > doesn't necessarily help with the overhead entirely, but it should help > substantially. I might be forgetting some important element as I have not > referred back to the code, but I believe that the only thing that is > necessary is for the developer to set a fixed cell size on the TableView > (via TableView#setFixedCellSize). When this happens, the TableView can 1) > reduce enormously the amount of computations it has to do for layout and 2) > virtualise the columns. I suspect 2 is your primary goal, but 1 shouldn't be > underestimated given the enormity of your table. > > Sean, it would be interesting if you could send me a sample application that > demonstrates your problem. I am always trying to optimise these virtualised > controls and would appreciate adding your specific use case to my suite of > tests. > > Thanks, > > -- Jonathan > > > On 15/08/2014 10:35 a.m., Tomas Mikula wrote: >> >> On Thu, Aug 14, 2014 at 9:01 PM, Sean True <sean.t...@gmail.com> wrote: >>> >>> We've been looking at very large tables for use in data grid display. >>> >>> Row count scales very nicely indeed, but column count is much more >>> problematic. >> >> To explain your observation: TableView is based on VirtualFlow, which >> optimizes the number of cells simultaneously attached to the scene >> graph in one direction (horizontal or vertical). For TableView, >> vertical VirtualFlow is used, which means rows are optimized >> (invisible rows are not in the scene graph), while all columns for >> each visible row are in the scene graph. >> >> To be able to scroll smoothly through the table, you would want a >> two-dimensional virtual flow. You can look at VirtualFlow.java from >> OpenJFX or from my alternative virtual flow implementation Flowless >> [1] to get an idea about the complexity of the one-dimensional case. >> >> If you don't require smooth scrolling and are fine with scroll by one >> row/column at a time, you could display a small table with fixed cell >> count, say 30x20 (maybe calculated dynamically based on the available >> area), and display your own scrollbars that will update the data model >> behind this small table. Not the best solution, but much less work. >> >> Regards, >> Tomas >> >> [1] https://github.com/TomasMikula/Flowless >> >>> In the March time frame, our tests showed that each column had >>> approximately 100KB overhead (using VisualVM), which is negligible at 100 >>> columns, but at 10,000 columns becomes an issue. We have real world use >>> cases of more columns than that . >>> >>> Is there planned effort to reduce the overhead, or are we looking at >>> likely >>> having to build our own table component to serve these large needs? >>> >>> -- Sean > >
