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

[Frederic Thevenet]

On Fri, 18 Dec 2020 11:39:04 GMT, Frederic Thevenet <fthevenet at openjdk.org> wrote:

>> 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?
>
> Unfortunately I've only seen it within an application with a fairly complex scene graph, which make isolating the issue  tricky. 
> 
> I'm still trying to reproduce it a minimal sample, but in the mean time, please have a look at the a screen capture below, which should at least help clarify the issue I'm observing:
> 
> ![8211294](https://user-images.githubusercontent.com/7450507/102610169-064d6000-412d-11eb-8ebd-b1999a6c6009.gif)
> 
> This snippet is captured after the window had been moved from a screen scaled to 100% to a second one scaled to 150%; notice how the controls in the "Chart Properties" pane only snap to pixel when the mouse pointer enters the pane.

Digging deeper into my own code, it appears that there are several areas where I need to account for screen scale within the application's code itself (i.e. I use coordinates from mouseEvent to set the layout of some elements, and these are not snapped), so it probably safe to ignore these issues in the context of the PR.

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