My application is running on an embedded platform. There is a home screen that has a stacked widget that lets you switch between different modes. I display a dialog in the center of the screen for things like setup and alarms. Currently I try to darken the background by drawing a translucent widget over the home sceen and then the dialog over that. Here is the code for my overlay widget:

Qt Code: 
  1. Overlay::Overlay( QWidget *parent_p )
  2.     : QWidget( parent_p )
  3. {
  4.     setAutoFillBackground( true );
  5.  
  6.     QPalette pal( palette() );
  7.     QColor color;
  8.     color.setRgba( FILL_COLOR );
  9.     pal.setBrush( QPalette::Window, QBrush( color ) );
  10.  
  11.     setPalette( pal );
  12.  
  13.     if ( parent_p )
  14.     {
  15.         resize( parent_p->size() );
  16.     }
  17. }
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This is really slow to draw and clear. Does anyone have a better solution for darkening the widgets behind a dialog?