On Thu, 23 Sep 2021 19:01:52 GMT, Marius Hanl <mh...@openjdk.org> wrote:
> This PR fixes an issue which is probably in JavaFX since VirtualFlow exists. > While horizontal scrolling any VirtualFlow control the left blue border > sometimes disappear/gets smaller. (see also image below) > > This can be fixed by **snapping** the scroll bar value (similar like e.g. a > **ScrollPane** does). > The same needs to be done on the table header as otherwise the column lines > might be 1 px off to the cell lines. > As a side effect this also fixes that the column lines sometimes get's blurry > when horizontal scrolling (see second image). > > While testing with **-Dglass.win.uiScale** I found out that the problem is > not fixed for a scale like 1.25 or 1.5, while it is fixed for 1 or 2. The > border sometimes disappears only when the snapped value is a decimal number > (which obviously does not happen on a scale of 1 or 2), e.g. something like > 12.6 but it will never disappear when it's a normal number, so e.g. just 12. > > That's why something like **Math.round(..)** or just a **cast** to an **int** > instead of snapping fixes this problem for all scales. I also didn't notice > any side effect. But not sure if this the right fix then. > How does JavaFX render a **node** when e.g. the x is a decimal number? And > does a decimal number make sense (Why we e.g. don't round the value)? > > Another explanation could also be that there is an issue somewhere deep > inside the node layout/snapping/Clip/Group/pixel rendering and to simply > round/cast the value just fixes the symptom here. > > In any case I'm open for any feedback, help or explaination. > I'm also glad for anything which might help identify the root cause here, if > any. > > --- > 1. >  > --- > 2. >  This pull request has been closed without being integrated. ------------- PR: https://git.openjdk.org/jfx/pull/630
