[Qt-interest] resizeEvent get's only called _after_ resize

[Christoph Fritz]

On Sunday, 19. July 2009, Sean Harmer wrote:

> > What I need is a function that gives me access to the
> > resize-process itself. So that the window can always stay in
> > 4:3 ratio and won't be snapped back after the resize event.
>
> Try reimplementing the int QWidget::heightForWidth ( int w )
> const function in your window class to return  a height
> appropriate to the passed width according to your desired
> aspect ratio.

Presentation of "Understanding Qt's Layouts", on sheet 40 says:
- Must reimplement heightForWidth(int) and set the 
height-for-width flag of QSizePolicy
- Can be used to keep constant aspect ratios
- Caveat: On X11, if the entire window has height-for-width, the 
window has no minimum size.

http://chaos.troll.no/~ahanssen/devdays2007/DevDays2007-Layouts.pdf

I tried so, but it didn't work. Any guess?

In the constructor I did:
  MainWindow::MainWindow(QWidget *parent)
      : QMainWindow(parent), ui(new Ui::MainWindow)
  {
      ui->setupUi(this);
      this->sizePolicy().setHeightForWidth(true);
  }

declared the reimplementation of heightForWidth:
  public:
      MainWindow(QWidget *parent = 0);
      ~MainWindow();
      virtual int heightForWidth ( int w ) const;

and wrote a 1:1 ratio test:
   int MainWindow::heightForWidth ( int w ) const {
       return w;
   }