On Sun, 2012-02-12 at 02:42 +0100, Krzysztof Kosiński wrote:
That's something I wondered about. Inkscape is generally not usable with touchscreen devices due to its interface design, which often requires precise manipulation and clicking on areas which are a few pixels wide. I also doubt whether any significant number of people can productively work with 2 traditional mice at once. Is there actually any real benefit to be gained from MPX support?
Those are a few very good questions.
The first point is that multitouch is something very different from multipointer (aka MPX). Both do happen to come from XInput2, but are distinct technologies.
Next is that we really do need to improve the UI so that it *can* be used on touchscreen devices. Much of that can come from a user selecting an appropriate GTK theme for touch, and Inkscape following the user preferences. However there are improvements that would help not only touch interfaces, but tablet use also. We also are seeing the number of touch capable notebooks and tablets grow, so being able to take advantage of those is good.
As a second touch issue, we can gain a lot from supporting common multitouch gestures. As Josh mentioned, zoom, pan, rotate, etc. are all common expected gestures nowadays. Other basic gestures can be included, and they can all be used to supplement the current interface. That is, using them does not require the main UI to be changed from what it currently is. And finally it is good to keep in mind that external touch devices are easy to buy and hook up. Even Apple's magic trackpad is well supported on Linux.
Now on to some MPX items.
It's not really as much about a single user with two mice. MPX just as easily works for a single Wacom user with a single pen and a mouse/puck on the same tablet. Or two pens. Much of the commercial software out there with tablet support already handles mulipointer, at least when it comes to Wacoms. So graphics professionals are already used to such workflows.
The next use case, that Josh mentioned, is with more than one person on the same document. For one case, Dave Crossland was asking about this for the font design workshops he's been running. Another common request has been for hands-on tutorials and training.
And then there is a common case for tablet owners where they can be using the stylus and tablet with their dominant hand, and want to use their normal mouse to work the UI buttons, etc. This can be especially handy when the keyboard has been moved to make room for the tablet.