Hi, On 06/25/2014 09:06 AM, Dmitry Kazakov wrote: > Hi, all! > > I am a developer from Krita painting application team. We recently did > quite much work on incorporating better tablet support in Krita. I have > several comments about your proposal of the tablet protocol (sorry for nor > replying directly, since I wasn't subscribed to the list before).
I just want to say that it is great to see a developer of a tablet using app get involved in this discussion, and I also your timing is excellent, joining the discussion while we are still actually discussing thanks. Thanks your input is very much appreciated. > 1) Axes. There should also be an axis for rotation of the stylus (Artpen) > and Tangential Pressure (for the wheel of the Airbrush). > 2) There is also Artpen type of stylus. In Qt it is called "Rotational > Stylus". > 3) Fingers. There is a complication in XInput2 right now, since touch > enabled Wacom devices have a special Finger XInput2 device, which provides > both interfaces: tablet and touch and therefore generates both types of > events. Right now Qt5 still cannot handle it properly, but the work is in > progress. From Krita point of view, the main usecase for us is to > distinguish whether the user paints with a finger of with the stylus. > Because most of the users prefer to disable painting with fingers and use > it for gestures/UI only (yes, palm detection works with non-100% > probability). > 4) Button Press/Release events should come in both cases: when the user > clicks on the stylus' buttons and when the stylus touches the surface of > the tablet. I'll leave commenting on the above up to the real experts on this topic. > 6) It might be a good idea to define the physical properties of the axes. > E.g. for tilt, rotation and tangential pressure. Afair, Wacom driver for > XInput returns some not-very-obvious values right now. One would need to > experiment to know what these numbers mean. AFAIK the plan is to normalize all the axis values, so for most axis they would get a value of 0.0 - 1.0, where some axis may be -1.0 - 1.0, e.g. pressure, with 0.0 - 1.0 being barely touching - max-pressure and negative values meaning in proximity but not touching. Regards, Hans _______________________________________________ wayland-devel mailing list [email protected] http://lists.freedesktop.org/mailman/listinfo/wayland-devel
