[Qt-interest] QDialog with rounded "corners"

[Gabriel M. Beddingfield]

On Thursday, February 10, 2011 08:08:00 am Markus Franke 
wrote:
> I am having problems when styling QDialog in my Qt
> application. Basically I would like to have dialog
> windows which have rounded corners. I have a class
[snip]
> 
> The result which I achieve are actually quiet similar to
> what I want. I see rounded "corners" but it seems like
> the background is not taken into account as I can see a
> few pixels of the background color in each of the
> corners. (see attached dialog.png)

I did pretty much the same thing with StretchPlayer:

   http://www.teuton.org/~gabriel/stretchplayer/

See src/PlayerWidget.cpp (and src/PlayerWidget.hpp).  The 
trick, in a nutshell, is:

   1. You gotta have a compositing window manager.
      (Most modern distros have them by default now)

   2. Set the WA_TranslucentBackground attribute.

   3. Create a mask for the rounded corners, and
      set it up in the paintEvent().

   4. I don't remember if it's required to derive from
      a QMainWindow or not.

BTW, doing this (esp. the mask) requires more CPU... which 
was kind of a pain in my app.

-gabriel