RFR: 8169501: GIF animation is too fast

[Kevin Rushforth]

On Fri, 15 May 2020 07:42:40 GMT, Bhawesh Choudhary <github.com+4208131+bhaweshkc at openjdk.org> wrote:

> issue is caused by the threshold value for frame duration used by javaFx before it gets normalized. JavaFx is using
> threshold value 10 while other browser (Safari, Firefox) is using 50 due to which, value between 10 and 50 don't get
> normalized and animation runs at faster speed. To fix the issue change frame duration normalization value to <= 50.
> Safari : https://bugs.webkit.org/show_bug.cgi?id=14413 Firefox : https://bugzilla.mozilla.org/show_bug.cgi?id=386269

While it does seem like the fix will make things better, the logic is a bit surprising to me. What it means is that
very small values in the range `[0,50]` (currently `[1,10]` before your fix) will get forced to 100, but moderately
small values, in the range `[51,99]` will be used directly. I wonder what the rationale was for this behavior in Safari
is? I would have thought just a simple clamp (either to 50 or 100) would make more sense, but perhaps matching the
popular browsers is better.

What I would like to see, though, is a comparison of behavior between:

* WebView (both before and after your proposed fix)
* JavaFX Image in an ImageView
* Firefox
* Safari
* Chrome

Can you find two images (the one in the bug report can be one of them) with a frame delay value in the 11-50 range and
also something in the 51-70 range and run the tests?

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PR: https://git.openjdk.java.net/jfx/pull/221