1906968 - Occasional spurious pen pointer event with pressure=0.5 tiltX=0 tiltY=0

Status: UNCONFIRMED

(Core :: Widget: Gtk, defect, P3)

Description

[Denilson Figueiredo de Sá]

Attachment: screen-recording.gif

Steps to reproduce:

• Firefox nightly 130.0a1 (2024-07-09) (64-bit)
• Manjaro Linux on x86_64
• KDE/Plasma with X11
• [056a:0016] Wacom Co., Ltd CTE-640 [Graphire4 (6x8)] using the default kernel drivers. (But hopefully reproducible with any pen tablet.)

Steps to reproduce:

1. Open https://output.jsbin.com/rawusar/4
2. Tap the pen onto the tablet, multiple times.

Actual results:

Randomly, the pen pressure is reported as 0.5 and both tiltX and tiltY are reported as 0.

Expected results:

Well, not that. That spurious pointer event is quickly followed by correct events with the expected amounts of pressure and tilt.

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This can also be reproduced on: https://patrickhlauke.github.io/touch/pen-tracker/
On this page, we can (randomly) see the wrong pressure/tilt values for a fraction of a second.

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This bug does NOT happen on Google Chrome on the same system.

This bug was originally mentioned in https://bugzilla.mozilla.org/show_bug.cgi?id=1705892#c7

I'm attaching a relevant portion of the terminal output from running with MOZ_LOG="Widget:5". If I were to guess, I would believe this bug happens whenever there are two consecutive Button 1 press lines in the log.

I'm attaching a short screen recording showing the bug in the linked webpage. The attached GIF corresponds to the attached log.

Comment 1

[Denilson Figueiredo de Sá]

Attachment: MOZ_LOG.txt

Comment 2

[Denilson Figueiredo de Sá]

This probably blocks bug 1631377