[tracker1]

I think that things like React, and React-Native show the opposite is true... composition of UI elements that are meant to be rendered in relative terms doesn't tend to work out well when you are trying to use absolute measurements in something like C++ with lower-level constructs.

The fact that it is XML is more convention in this case... even with React, it's translated to coded controls via strict rules.. and is relatively easy to manage and reason with.

[hugoamnov]

One thing you misunderstood :

You don't specify any absolute measurement when using kiUi from C++.

The whole point is to get rid of them. They are calculated under the hood.

The style gives the necessary hints. And this is done in a way entirely separate from the UI code itself.

Think of the C++ code doing what is regularly done in both HTML and Javascript, and the kiUi style sheet as what is regularly done in CSS.