<font size="2"><font face="verdana,sans-serif">Does this help:</font></font><div><font class="Apple-style-span" face="verdana, sans-serif"><br></font><div><font size="2"><font face="verdana,sans-serif"><a href="http://dzenanz.wordpress.com/2011/04/05/qwidget-must-construct-a-qapplication-before-a-qpaintdevice/">http://dzenanz.wordpress.com/2011/04/05/qwidget-must-construct-a-qapplication-before-a-qpaintdevice/</a><br>

</font></font><div><div><br><div class="gmail_quote">On Mon, Aug 15, 2011 at 09:09, Leonid Dulman <span dir="ltr">&lt;<a href="mailto:leonid_dulman@yahoo.co.uk">leonid_dulman@yahoo.co.uk</a>&gt;</span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex;">

Hi to All<br>
In next Example<br>
#include &quot;qmainwindow.h&quot;<br>
 #include &quot;qapplication.h&quot;<br>
<br>
 #include &lt;QVTKWidget.h&gt;<br>
 #include &lt;QVTKApplication.h&gt;<br>
<br>
 #include &lt;vtkRenderWindow.h&gt;<br>
 #include &lt;vtkRenderer.h&gt;<br>
 #include &lt;vtkTextSource.h&gt;<br>
 #include &lt;vtkVectorText.h&gt;<br>
 #include &lt;vtkPolyDataMapper.h&gt;<br>
 #include &lt;vtkActor.h&gt;<br>
<br>
 int main( int argc, char **argv )<br>
 {<br>
  QVTKApplication app(argc,argv);<br>
  QMainWindow *mainWindow = new QMainWindow;<br>
   mainWindow-&gt;setFixedSize(640,360);<br>
<br>
  QVTKWidget *widget = new QVTKWidget;<br>
   mainWindow-&gt;setCentralWidget(widget);<br>
<br>
  vtkTextSource *text = vtkTextSource::New();<br>
   text-&gt;SetText(&quot;Hello World!&quot;);<br>
   text-&gt;BackingOff();<br>
  vtkVectorText *vectorText = vtkVectorText::New();<br>
   vectorText-&gt;SetText(&quot;QVTKWidget&quot;);<br>
  vtkPolyDataMapper *textMapper = vtkPolyDataMapper::New();<br>
   textMapper-&gt;SetInput(text-&gt;GetOutput());<br>
  vtkPolyDataMapper *vectorTextMapper = vtkPolyDataMapper::New();<br>
   vectorTextMapper-&gt;SetInput(vectorText-&gt;GetOutput());<br>
  vtkActor *textActor = vtkActor::New();<br>
   textActor-&gt;SetMapper(textMapper);<br>
  vtkActor *vectorTextActor = vtkActor::New();<br>
   vectorTextActor-&gt;SetMapper(vectorTextMapper);<br>
  vtkRenderer *renderer = vtkRenderer::New();<br>
   renderer-&gt;SetBackground(0.4,0.6,0.8);<br>
   renderer-&gt;AddActor(textActor);<br>
   renderer-&gt;AddActor(vectorTextActor);<br>
  vtkRenderWindow *renderWindow = vtkRenderWindow::New();<br>
   renderWindow-&gt;AddRenderer(renderer);<br>
   renderWindow-&gt;SetStereoTypeToDresden();<br>
<br>
  widget-&gt;SetRenderWindow(renderWindow);<br>
  mainWindow-&gt;show();<br>
  app.aboutQt();<br>
     return app.exec();<br>
 }<br>
<br>
I have got massage &quot;QWidget:Must construct a QApplication before a QPaintDevice&quot; only in Windows 7 SP1, in Windows XP and linux I have no any problems<br>
<br>
My installation is<br>
Qt 4.7.3<br>
VTK 5.9.0 (from git)<br>
Thank you. Leonid<br>
<br>
<br>
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</blockquote></div><br></div></div></div></div>