JDK-8242122 : Total deltas for scroll events from mouse wheel are wrong
  • Type: Bug
  • Component: javafx
  • Sub-Component: window-toolkit
  • Affected Version: openjfx14
  • Priority: P4
  • Status: Open
  • Resolution: Unresolved
  • OS: os_x
  • CPU: x86_64
  • Submitted: 2020-04-03
  • Updated: 2020-04-03
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tbdUnresolved
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Description
When scroll events are generated via the mouse wheel, the total delta values returned by the event object are not correct.
The documentation says: "The totalDeltaX and totalDeltaY contain the cumulative values for the whole gesture, zeros for mouse wheel". As you can see in the output of the test program below, the total-deltas for y are not zeros. The values are: e.getDeltaX(), e.getTotalDeltaX(), e.getDeltaY(), e.getTotalDeltaY(), e.getTouchCount() 

setOnScroll: 0,000000 0,000000 1,000061 1,000061 0
setOnScroll: 0,000000 0,000000 1,000061 1,000061 0
setOnScroll: 0,000000 0,000000 1,000061 1,000061 0
setOnScroll: 0,000000 0,000000 1,000061 1,000061 0
setOnScroll: 0,000000 0,000000 4,296417 4,296417 0
setOnScroll: 0,000000 0,000000 -1,000061 -1,000061 0
setOnScroll: 0,000000 0,000000 -11,195526 -11,195526 0
setOnScroll: 0,000000 0,000000 -38,627014 -38,627014 0
setOnScroll: 0,000000 0,000000 -50,805664 -50,805664 0
setOnScroll: 0,000000 0,000000 -52,142639 -52,142639 0 

This was originally reported in the context of https://bugs.openjdk.java.net/browse/JDK-8236971
Comments
This is likely in the window-toolkit code.
03-04-2020