[Qt4-preview-feedback] Ability to read the border and padding properties of styled widgets

[Olivier Goffart]

On Sunday 01 March 2009 23:02:39 Craig Scott wrote:
> I understand there's no API and that it's not currently in the roadmap,
> but consider widgets that need to reimplement their sizeHint() function.
> A good example of a motivating case is a QLabel with word wrapping
> enabled. The sizeHint() changes depending on what horizontal constraints
> are placed on the widget. While it could be argued that the size hint
> specifies what the widget wants in an unconstrained world, it still
> makes sense (to me at least) that if it can be told about its
> constraints then it should be able to give the best possible size hint.
> If the width is constrained such that the label has to wrap, then the
> sizeHint() should have a deeper height to reflect this. I would have
> thought that this particular example would occur frequently enough to
> warrant some consideration. At the moment, if a widget's style sheet
> contains non-zero padding or borders, there is no way for a
> reimplemented sizeHint() to know about it and therefore it is not
> possible to account for it.

You can call some style prinitives, such as 
style()->subElementRect(QStyle::SE_FrameContents ,  &opt, this);
And use the difference between opt.rect and the returned rect to get the 
margins you should apply.