1 files changed, 125 insertions, 0 deletions
diff --git a/examples/opengl/overlay_x11/main.cpp b/examples/opengl/overlay_x11/main.cpp
new file mode 100644
index 000000000..70a6f4362
--- /dev/null
+++ b/examples/opengl/overlay_x11/main.cpp
@@ -0,0 +1,125 @@
+/****************************************************************************
+**
+** Example application showing how to use TQt and TQt OpenGL Extension on an 
+** X11 overlay visual 
+**
+** Copyright (C) 1999-2008 Trolltech ASA.  All rights reserved.
+**
+** This file is part of an example program for TQt.  This example
+** program may be used, distributed and modified without limitation.
+**
+*****************************************************************************/
+
+#include <qapplication.h>
+#include "gearwidget.h"
+#include "rubberbandwidget.h"
+
+#if defined(Q_WS_X11)
+#include <X11/Xlib.h>
+#endif
+
+TQColor findOverlayTransparentColor()
+{
+    TQColor invalidColor;
+
+#if defined(Q_WS_X11)
+
+    Display* appDisplay;
+    Visual* appVisual;
+
+    // The static methods are called 'App' in TQt 2.x
+#if QT_VERSION < 200
+    appDisplay = TQPaintDevice::x__Display();
+    appVisual = (Visual*)TQPaintDevice::x11Visual();
+#else
+    appDisplay = TQPaintDevice::x11AppDisplay();
+    appVisual = (Visual*)TQPaintDevice::x11AppVisual();
+#endif
+
+    qDebug( "Default Visual ID: 0x%x", (int)XVisualIDFromVisual(appVisual) );
+
+    typedef struct OverlayProp {
+	long  visual;
+	long  type;
+	long  value;
+	long  layer;
+    } OverlayProp;
+
+    TQWidget* rootWin = TQApplication::desktop();
+    if ( !rootWin )
+	return invalidColor; // Should not happen
+
+    Atom overlayVisualsAtom = XInternAtom( appDisplay, 
+					   "SERVER_OVERLAY_VISUALS", True );
+    if ( overlayVisualsAtom == None ) {
+	warning( "Server has no overlay visuals" );
+	return invalidColor;
+    }
+
+    Atom actualType;
+    int actualFormat;
+    ulong nItems;
+    ulong bytesAfter;
+    OverlayProp* overlayProp;
+    int res = XGetWindowProperty( appDisplay, TQApplication::desktop()->winId(),
+				  overlayVisualsAtom, 0, 10000, False, 
+				  overlayVisualsAtom, &actualType, 
+				  &actualFormat, &nItems, &bytesAfter,
+				  (uchar**)&overlayProp );
+
+    if ( res != Success || actualType != overlayVisualsAtom 
+	 || actualFormat != 32 || nItems < 4 ) {
+	warning( "Failed to get overlay visual property from server" );
+	return invalidColor;
+    }
+
+
+    for ( uint i = 0; i < nItems/4; i++ ) {
+	if ( (VisualID)overlayProp[i].visual == XVisualIDFromVisual(appVisual)
+	     && overlayProp[i].type == 1 )
+	    return TQColor( qRgb( 1, 2, 3 ), overlayProp[i].value );
+    }
+
+    qWarning( "Default visual is not in overlay plane" );
+    return invalidColor;
+
+#else // defined(Q_WS_X11)
+    qWarning( "Wrong window system - Only X11 has overlay support." );
+    return invalidColor;
+#endif
+}
+
+
+int main( int argc, char **argv )
+{
+    TQApplication::setColorSpec( TQApplication::CustomColor );
+    TQApplication a( argc, argv );
+
+    if ( !TQGLFormat::hasOpenGL() ) {
+	qWarning( "This system has no OpenGL support. Exiting." );
+	return -1;
+    }
+
+    TQColor transparentColor = findOverlayTransparentColor();
+    if ( !transparentColor.isValid() ) {
+	qWarning( "Failed to get transparent color for overlay. Exiting." );
+	return -1;
+    }
+
+    TQWidget top;
+    a.setMainWidget( &top );
+    top.setGeometry( 50, 50, 600, 400 );
+
+    // Make an OpenGL widget. It will use the deepest visual available
+    // (typically a TrueColor visual), which typically is in the normal layer.
+    GearWidget g( &top );
+    g.setGeometry( 20, 20, 560, 360 );
+
+    // Put the rubberband widget (which uses the default, i.e. overlay visual)
+    // on top of the OpenGL widget:
+    RubberbandWidget r( transparentColor, &top );
+    r.setGeometry( 20, 20, 560, 360 );
+
+    top.show();
+    return a.exec();
+}