[PATCH]QT_WIN32_3_3_BRANCH-GDI Leak

Chris January chris at atomice.net
Tue Dec 14 15:12:05 CET 2004


I thought I'd also saw the problem even when I disabed the window procedures
(and hence all painting) but maybe that's my imagination.
 
I thought qmake could generate VC++ project files but maybe I'm wrong there.
Personally I use Borland CBuilderX since the Borland incremental linker is
much faster than the Microsoft or GNU one.
 
The Trolltech position of this port is unknown. They know it exists and
they've never complained about it. They have said they won't release a GPL
version of Qt/Win32 but their reasoning has become indefensible since they
released the GPL Mac OS X version.
As for legal issues - there are none we are aware of. We do have to be
careful no code slips on from the commercial version of Qt (or any other
imcompatibly licensed product for that matter).
 
Chris


  _____  

From: REGAT-BARREL Aurélien [mailto:arbvtk at yahoo.fr] 
Sent: 14 December 2004 13:49
To: kde-cygwin at kde.org
Subject: RE: [PATCH]QT_WIN32_3_3_BRANCH-GDI Leak


Hi,
Sorry, I didn't subscribe to the ml, I didn't find a link to do it from the
project page.
Yes, the problem you describe is what I found. This behaviour (widgets
become dark/black, whole screen becomes corrupted...) is typically due to a
GDI leak. I ran this tool:
http://msdn.microsoft.com/msdnmag/issues/03/01/GDILeaks/
and it appeared that it was a GDI pen leak (hundreds of pens no freed). So I
looked for CreatePen and quickly found the guilty. Now it works fine (after
removing this 2 lines).
There is another problem with erasing. I didn't find why it causes
flickering. There are other problems too (mouse moves cause flickering too,
etc...). I can't spend much time, for now, but later I will try to help you.
I use Visual C++ 2003 and I was unable to create VC++ project files with
qmake & .pro files. It is annoying because without the debuger & source code
navigation I am lost :-) Is there a trick ?
What is the position of Trolltech about this port ? Can we use it without
worry ?
 
Regards.
 
    Thanks for this. Can you explain exactly what problems you were seeing
with
    painting?
     
    There is a long-standing problem with example programs such as
scrollview
    (resize the window few time to see what I mean) where painting in the
window
    and even the whole screen becomes corrupted. I think I've narrowed this
down
    to the window hierachy but maybe you have some ideas that could help?
     
    Chris
    Hi,
    This is my first post to this ml so excuse me if I am doing something
wrong
    :-)
    I downloaded and tried qt-3 QT_WIN32_3_3_BRANCH. It quickly appeared
that
    there was a problem with painting. I ran GDI leaks detection tools and
found
    a problem with pens. The problem is in kernel/qpainter_win.cpp, line
2887:
            HPEN pen = CreatePen (PS_SOLID, 1, RGB (0, 0, 0));
            SelectObject (hdc, hpen);
    note the use of pen with CreatePen and hpen with SelectObject. I simply
    removed this 2 lines, and it works better now.
    I hope this helps.



Aurelien REGAT-BARREL 




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