Multiple viewport support

[dg0yt]

puzzlepaint reported on Sourceforge [tickets:#123]:

It was originally planned to provide the possibility for "split screen" views, where the same part of a map can be shown with different template visibility settings (for example: orthophoto on one side, survey drawings on right side). Determine if useful enough to be implemented.

[dg0yt]

02JanDal posted on Sourceforge:

For this ticket and for creating an Android version I think we would win a lot by creating a MVC (Model/View/Controller) system for the map.
Qt item views framework for example can display the same data in multiply views.

I'm not 100% sure, but I think a bit like this already exist (Map for the model and MapWidget for the view), so partly this should already work. I don't have access to the code right now, but I think I have seen some comments in the code indication a Map object can already be displayed in multiply views.

Reason I said this would help for the Android version to is that on Android it might be interesting to create a QML UI there (even though that would mean a lot of more work than simply using the widget based UI.

Jan