This adds the tablet tester from Drawpile (original by Calle Laakkonen) into Krita. I made a few changes to make it compile. It can be accessed from the Tablet page of the config dialog.
With the tablet tester, users with tablet issues can provide a screenshot and copy the log output for support requests, which would be easier than obtaining a tablet log with the existing setup (e.g. not needing to download DebugView on Windows).
However, the log output is a bit less detailed than the existing tablet log. Perhaps we should look into hooking the existing tablet logger to the tablet tester.
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Working branch: https://github.com/KDE/krita/compare/master...alvinhochun:alvin/D12710-tablet-tester
Current patch contains changes up to 0202723 Adapt and enable tablet tester