WM_POINTER rather than WM_GESTURE

[baconpaul]

From Slack regarding Windows Touch and #1461 and a potential improvement in the future to @nathankopp change (which works and is merged). I agreed with Nathan that it would be better but working is a good next step; so merged the current change. If someone comes along and wants to do a serious bit of work on windows touch in vstgui, this issue will help!

kurasu 2:58 AM
you don't want to use WM_TOUCH or WM_GESTURE, WM_POINTER is where its at

Nathan Kopp 3:59 AM
Just took a look at WM_POINTER. Looks like this replaces WM_GESTURE and WM_TOUCH. Not sure why the MS docs haven't been updated to mention the newer features. Anyway, WM_POINTER also seems like it will take more effort than using WM_GESTURE. The benefit of my current method is that I only pay attention to the gesture-begin and gesture-end messages, and let everything pass through to DefWindowProc(). Then, the default gesture handler converts the touches into mouse events. There are some downsides (such as a "dead zone" around the initial touch point, which is not good if you want to move a slider just a tiny bit), but the benefit is that it requires much less code. I'm going to push my change (since it's working), but if anyone wants to improve things to use WM_POINTER instead, I won't be offended. 🙂