RFR: 8211294: ScrollPane content is blurry with 125% scaling

[Kevin Rushforth]

On Thu, 17 Dec 2020 19:30:17 GMT, Kevin Rushforth <kcr at openjdk.org> wrote:

>> I've opted for the cache and check for screen scale solution, as I agree it presents less risks of leaked or missing listeners down the road.
>> There's a slight unexpected drawback I've noticed, though, which is that the repaint for the affected Region does not seem to occur right away on moving the window to another screen, but only once the Region is interacted with (e.g. hovering the mouse over it).
>
> Your latest patch looks exactly like what I would expect. I need to do some multi-screen testing on Windows with different scale factors.
> 
>> ... the repaint for the affected Region does not seem to occur right away on moving the window to another screen, but only once the Region is interacted with (e.g. hovering the mouse over it).
> 
> This seems like a different (and preexisting) bug then. I think we're up to three follow-on issues if I haven't lost track:
> 
> 1. Rendering a cached node doesn't match rendering it directly even when the transform is unchanged.
> 2. TextFlow: methods copied from Region have not picked up subsequent changes in those methods
> 3. Need to Render and layout scene out when scale changes (either when moving to a screen with a different scale or when the scale changes as the result of changing the setting of the current screen)

I did some testing with your latest patch, and I don't see any problem when dragging a window between screens with different scales. It seems to be recalculating the cached insets and using them in layout as I would expect. Do you have a test case that shows the problem?

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PR: https://git.openjdk.java.net/jfx/pull/308