JDK-8229751: [macOSX] trackpad scrolling too fast

[mipastgt]

When you try to scroll something on a Mac with a trackpad (external or internal) then this is so fast that it is practically unusable.

I am talking here about the scroll gesture where you move two fingers up and down in parallel! At first I thought I was doing something wrong in interpreting the event data but I now stumbled over a case where this happens without my intervention.

This can be shown easily with a WebView and Google-Maps. I have attached a little test program which opens Google-Maps in a JavaFX WebView. Run this program in parallel with any Web-Browser (Firefox, Chrome, ...) also showing Google-Maps. Then try to zoom in and out of the map with the two-finger scroll gesture (not the pinch-gesture!) on both systems and you will see the difference. The zoom in the WebView is much too fast to be usable in contrast to the zoom in the browser which is ok.

This issue is probably related to https://bugs.openjdk.java.net/browse/JDK-8218424

I report this issue for the Mac only because I don't have any other system on which I could verify this. So I don' know whether this behaviour is mac-specific or not.

I have tested this with:

java.vm.name: OpenJDK 64-Bit Server VM java.runtime.version: 12.0.2+10 javafx.version: 13-ea

WebViewZoomDemo.java.zip

[johanvos]

This is very likely related to JDK-8218424 indeed.

[mipastgt]

I just reported this to https://bugreport.java.com too: internal review ID : 9061930

[kevinrushforth]

This has now been transferred to the JDK project in JBS as JDK-8229751.