Stylus pressure sensitivity (Wacom on Yoga X1 rd gen) only starts to work with delay during stroke
hile using Xournal/Xournal++ (which is based on GTK+) on Windows with a Lenovo X1 Yoga (3rd Gen), I noticed that pressure sensitivity only enables with some delay during the stroke. When I start the stroke, it starts with a thick stroke, followed by a glitch and then switches to pressure sensitive mode. I have raised an issue in Xournal++ respository on this behavior already (https://github.com/xournalpp/xournalpp/issues/1094) Here you can see the behavior on Xournal++.
The problem does appear with other GTK-based programs as well, but not with other software (Windows Ink, Drawboard PDF, etc., ruling out a hardware error). We could reproduce the behavior using the gtk3-demo program
Steps to reproduce
On a Lenovo X1 Yoga, 3rd gen (20LE version), do the following
- Start gtk3-demo
- Select "Touch and drawing tablets"
- When I approach the screen with the stylus, the demo first detects a "System Aggregated Pointer" without pressure sensistitivity (see first picture below)
- After roughly 1 second (the windows waiting cursor will complete a circle in ca. 1 second), the device switches to Source "WACOM Tablet ISD Stylus" and the pressure sensitivity works (see second picture below). When I stop writing, after a few seconds, the device will fall-back into the original state and I have to go through the 1 second again, waiting until the device is detected
- Interestingly, it appears that while I press a key on the keyboard while approaching the the screen with the stylus, it is immediately detected, so it seems to be a delay that is shortcut by pressaing a key. Obviously, this is not possible when in tablet mode.
Current behavior
Currently, the pressure sensititivity is not usable, as it only switches on with a delay during keystroke on a Yoga X1 (3rd gen) with built-in pen. This severely limits applicability of pressure sensitivity and is hence a serious bug. Only after 1 second and with a glitch, pressure sensitivity is switched on. The issue seems to be related to a badly detected pen, and detection seems to have a delay. Note that the delay can be circumvented by pressing a key while approaching, triggering some detection event (maybe the detection is only polling semi-regularly with some delay?)
Expected outcome
The expected outcome would be an immediate detection of the styles and hence an immediate (no lag/delay) enabling of pressure sensitivity.
Version information
- Lenovo Yoga X1, 3rd gen, 20LE version with integrated Stylus
- Windows 10, Version 1809 (Build 17763.437)
- GTK+ 3.22.30 (64 bit on Windows, x86, downloaded using MSYS2)