8169501: GIF animation is too fast

[bhaweshkc]

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

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Progress

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Issue

• JDK-8169501: GIF animation is too fast

Download

$ git fetch https://git.openjdk.java.net/jfx pull/221/head:pull/221
$ git checkout pull/221

[bridgekeeper]

👋 Welcome back bhaweshkc! A progress list of the required criteria for merging this PR into master will be added to the body of your pull request.

[mlbridge]

Webrevs

• 00: Full (0f3f325)

[kevinrushforth]

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?

[kevinrushforth]

/reviewers 2

[openjdk]

@kevinrushforth
The number of required reviews for this PR is now set to 2 (with at least 1 of role reviewers).

[kevinrushforth]

This is pending response to comments above.

[bhaweshkc]

10ms                   11ms                  12ms                  15ms

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19ms                  20ms                  21ms                  40ms                  

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75ms                  Original

Without the fix, gif animation speed matches for all interval gifs with all other browser (Which includes firefox, safari, chrome).
Only animation speed for gif file which is attached in issue doesn't match. javafx webkit plays it faster.
Imageview plays everything at its original speed. No clamping happens here.

[nlisker]

Is this related to https://bugs.openjdk.java.net/browse/JDK-8209560?

[bhaweshkc]

Is this related to https://bugs.openjdk.java.net/browse/JDK-8209560?

it seems not.

[kevinrushforth]

Using the images you posted above, it appears that the browsers (Firefox and Edge on Windows, Firefox and Safari on Mac) have a threshold of 20ms, not 51 ms. Looks like the formula should be

delay < 20 : set to 100
delay >= 20 : use the value as is

Your fix does make the 19 ms image match the browsers (whereas existing WebView is too fast), but the 20ms, 21ms, and 40ms images no longer do (they are fine in the existing WebVIew and too slow with your patch).

So I recommend changing the value to 20 and then re-testing.

[kevinrushforth]

This PR is on hold. It can be reopened or a new PR can be sent as and when it is ready to proceed.