[Qt-qml] Advanced layout support

[jens.bache-wiig at nokia.com]

> Great apologies to all for "hijacking" this thread, so I'll just throw in a summary of the "desires" that were explicitly mentioned in this thread, which a "QML-layout-thingie" might want to address:

I am afraid I still don't quite understand how you are proposing that layouts should change. What we are currently discussing is simply extending and adding convenience to the mechanisms (Row, Column) that are already present in the language. As a developer, I suspect that presenting some small code snippets that demonstrate what this will look like is a more effective way of communicating your ideas. Keep in mind that baseline anchoring, is already fully supported in Qt Quick. We simply need to set the text baseline on the components themselves to enable this feature.

> (a) Need to handle QML component stretching, individual item spacing, minimum/preferred/maximum size policies, like "row-layout" and "column-layout" (Adriano)
> 
> (b) Want to center items vertically at their baseline by default (Jens,Adriano)
> 
> (c) Need "splitters" (Jens)

All of these three are already implemented and the discussions are mostly focused on how to align and complete the API.

> (d) (concern), The current "wrapping behavior" in QtQuick's "Grid" is different from GridLayout and cannot be unified (Jens)

I was only pointing out that Grid and GridLayout would have to be two different elements since they have different use cases.
Trying to force them both into the same API did not really make sense.

> (e) Need to align QML components that are in different containers (like different group boxes) (André)

I don't think that is something we can or should solve in Layouts. The question seems to be if you could anchor to something that is not the immediate parent.

> (f) Want "typesetting" placement conventions for QML components (charley)

Again, we might need some code to get a better understanding of what you are proposing. 

Regards,
Jens Bache-Wiig