[Qt-interest] Invalid background rendering

[K. Frank]

Hello -

I believe I see the behavior you are describing.  (I don't know enough about
how the transparent stuff is supposed to work to have an opinion as to
whether it's a bug.)

Specifically, after I start the program I see two white text fields on a darkish
green background ("Button 1" and "Button 2").  If I change focus away from
the WidgetBug app, the green background becomes slightly lighter and more
pastel.  If I hover the mouse over either of the buttons, the color of just that
button becomes still a little lighter, and the text turns yellow.  Moving the
mouse off of that button causes that button's green color to lighten still a
little more, and the text turns back to white.  (I can repeat this process with
the other button.)  Resizing the app to a larger size causes the background,
including the area around the buttons, to revert back to the original dark green
color it had when the app first started.

I wouldn't say I see a border to the buttons -- I just a button
background, if you
will, that is a lighter shade of green than the app background.

I unzipped your WidgetBug.zip file, ran qmake, and then mingw32-make.  I built
this with 32-bit mingw on 64-bit windows 7.  My versions are reported
as follows:

   C:\...>qmake --version
   QMake version 2.01a
   Using Qt version 4.6.1 in C:/...

   C:\...>mingw32-make --version
   GNU Make 3.81
   ...
   This program built for i386-pc-mingw32

   C:\...>g++ --version
   g++ (TDM-2 mingw32) 4.4.1


I could try other things, if that would be helpful.

Good luck.


K. Frank


On Sun, Apr 11, 2010 at 1:42 PM, Tr3wory <tr3w at freemail.hu> wrote:
> Hi!
>
> I have a widget with transparent background.
> In the recent versions of Qt (namely 4.6.1 and 4.6.2) I found a very
> strange behavior:
> after some update it will be opaque.
>
> I created a minimal example with 2 buttons. The buttons don't have
> border and background, but after one hover event it will have.
>
> Can somebody confirm this?
>
> tr3w
>
> P.S.: I use Mingw 4.4 on Windows XP.