When thinking about touchscreen interactions, I believe we should consider these situations:

1. Tablet on hand with both multi-touch and direct pen input (e.g. Cintiq companion, Surface Pro and 2-in-1 clones, etc.)
   • No keyboard and mouse.
   • Only one hand available to perform actions. Either with the pen or two fingers at most (for me while holding the pen securely and comfortably).
2. Monitor / device on desk or mounted, with both multi-touch and direct pen input (e.g. Cintiq touch, Surface Studio, etc.; 2-in-1 devices on desk)
   • Keyboard is usually available, but it might not be the most intuitive input mode while drawing.
   • Both hands can be available for input actions, though one is holding the pen most of the time.
   • Avoid switching between keyboard and touchscreen input as it may involve heavy hand movements.
3. Actual laptops (non-2-in-1 and not flippable) with a touchscreen (and possibly direct pen input) for some reasons...
   • Keyboard available.
   • Does anyone actually do digital art with this setup though?
4. Touchscreen monitor with a standalone drawing tablet
   • Keyboard is usually available.
   • I have no clue whether users would want to use the touch screen for input when drawing...
5. Touchscreen-only setup (no pen / keyboard / mouse)

There are some technical points to consider:

1. How Qt handles simultaneous touch events on multiple widgets
2. How the OS / drivers handle pen and touch input together
   • Palm rejection might interfere with touch events while pen is in proximity
3. The effects of synthesized mouse events