On Sat, 5 Mar 2022 13:58:54 GMT, Alexander Scherbatiy <alex...@openjdk.org> wrote:
> Tapping on a button and next tapping on another place on the screen leads > that the button is pressed twice on a Raspberry Pi with Touchscreen. > > For example, run the > [JFXButtonExample](https://bugs.openjdk.java.net/secure/attachment/98181/JFXButtonExample.java) > > app and first tap on the button in the left bottom side of the screen and > second tap on the center of the screen. > > This is a log of the state from > LinuxStatefulMultiTouchProcessor.processEvents() method when > `System.out.printf("state: %s%n", state);` code is added before the line: > https://github.com/openjdk/jfx/blob/2e8a4a5e97bb88a5807ae5fe075b98e1d54a4ca0/modules/javafx.graphics/src/main/java/com/sun/glass/ui/monocle/LinuxStatefulMultiTouchProcessor.java#L140 > > state: TouchState[1,TouchState.Point[id=91,x=257,y=419]] > state: TouchState[1,TouchState.Point[id=91,x=257,y=420]] > state: TouchState[0] > Hello World! > state: > TouchState[2,TouchState.Point[id=91,x=257,y=419],TouchState.Point[id=92,x=410,y=265]] > state: > TouchState[2,TouchState.Point[id=91,x=257,y=419],TouchState.Point[id=92,x=409,y=267]] > state: > TouchState[2,TouchState.Point[id=91,x=257,y=419],TouchState.Point[id=92,x=408,y=286]] > state: TouchState[0] > Hello World! > > The TouchState contains only button coordinates (x=257,y=419) for the first > tap on the button. > The TouchState contains both the button coordinates (x=257,y=419) and > coordinates of the center of screen (x=408,y=286) for the second tap on the > center of the screen. > > This happens because when LinuxStatefulMultiTouchProcessor.processEvents() > pushes the state with current touches to the pipeline the > LookaheadTouchFilter saves the current state and copies the previous saved > state to the current state. > https://github.com/openjdk/jfx/blob/2e8a4a5e97bb88a5807ae5fe075b98e1d54a4ca0/modules/javafx.graphics/src/main/java/com/sun/glass/ui/monocle/LookaheadTouchFilter.java#L74 > > That leads that the already deleted touch state (which contains the button > coordinate) is restored. > > The proposed solution is to put the copy of the touch state to the pipeline . > > Printing the touch state after the fix shows the log: > > state: TouchState[1,TouchState.Point[id=65,x=267,y=423]] > state: TouchState[1,TouchState.Point[id=65,x=269,y=425]] > state: TouchState[0] > Hello World! > state: TouchState[1,TouchState.Point[id=66,x=414,y=243]] > state: TouchState[1,TouchState.Point[id=66,x=414,y=238]] > state: TouchState[0] > > The TouchState does not contains the button coordinates for the second tap. The fix looks OK to me. Since it is in Monocle, maybe @johanvos can review it? ------------- PR: https://git.openjdk.java.net/jfx/pull/746
