Don't touch paint when multiple fingers were down
Previously, you could put two fingers down to zoom the canvas, then lift one of them and enter touch painting. This is nonsense behavior and just lead to random blotches appearing when having touch painting enabled, so now that gets blocked for the current touch operation if multiple fingers have ever been down for it.
Test Plan
- Enable touch painting.
- Put two fingers down and pinch.
- Lift one finger, keep the other down.
- Move the other finger. Observe that nothing happens instead of a stroke starting.
Formalities Checklist
- I confirmed this builds.
- I confirmed Krita ran and the relevant functions work.
- I tested the relevant unit tests and can confirm they are not broken. (If not possible, don't hesitate to ask for help!)
- I made sure my commits build individually and have good descriptions as per KDE guidelines.
- I made sure my code conforms to the standards set in the HACKING file.
- I can confirm the code is licensed and attributed appropriately, and that unattributed code is mine, as per KDE Licensing Policy.
- Does the patch add a user-visible feature? If yes, is there a documentation MR ready for it at Krita Documentation Repository?
Reminder: the reviewer is responsible for merging the patch, this is to ensure at the least two people can build the patch. In case a patch breaks the build, both the author and the reviewer should be contacted to fix the build. If this is not possible, the commits shall be reverted, and a notification with the reasoning and any relevant logs shall be sent to the mailing list, kimageshop@kde.org.