RFR: 8185886: Improve scrolling performance of TableView and TreeTableView [v4]

[yosbits]

On Wed, 2 Sep 2020 10:46:48 GMT, Jeanette Winzenburg <fastegal at openjdk.org> wrote:

>> When the startup time is measured by eye, the impression changes depending on the individual difference.
>> The effect of runLater affects your experience.
>> 
>> However, I succeeded in further improving performance by eliminating another bottleneck in TreeTableView. Of course, it
>> also includes improvements in startup time.
>> I plan to commit at a later date.
>
>> 
>> 
>> When the startup time is measured by eye, the impression changes depending on the individual difference.
> 
> my eye is a precision instrument :) Seriously, who would do such a thingy? Obviously, it must be measured, for zeroth
> approximation doing so crudely by comparing currentMillis before/after showing is good enough to "see" the tendency.
>> The effect of runLater affects your experience.
> 
> that's why you shouldn't do it when trying to gain insight into timing issues ;)
> 
>> 
>> However, I succeeded in further improving performance by eliminating another bottleneck in TreeTableView. Of course, it
>> also includes improvements in startup time.
> 
> cool :)

Column virtualization causes shortness of breath when scrolling a large stroke horizontally.
This does not happen when stroking on the scrollbar. Looks like a potential problem with VirtualFlow.

If you are worried about shortness of breath, the following code will help reduce the problem.


 Java
　private static final int OVERLAP_MARGIN = 500;

    private static boolean isOverlap(double start, double end, double start2, double end2){
    	start = Math.max(start-OVERLAP_MARGIN, start2);
    	end = Math.min(end+OVERLAP_MARGIN, end2);
        return (start<=end2 && end >= start2);
    }

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PR: https://git.openjdk.java.net/jfx/pull/125