-Added check to qgsrect intersect to see if rects actually intersect

-Patch for custom dialog box, closes ticket #1232

git-svn-id: http://svn.osgeo.org/qgis/trunk/qgis@9267 c8812cc2-4d05-0410-92ff-de0c093fc19c

Author: ersts

src/app/qgscustomprojectiondialog.cpp

@@ -855,6 +855,7 @@ void QgsCustomProjectionDialog::on_pbnSave_clicked()
 
   sqlite3_finalize( myPreparedStatement );
   sqlite3_close( myDatabase );
+  pbnDelete->setEnabled( true );  
 }
 
 void QgsCustomProjectionDialog::on_pbnCalculate_clicked()

src/core/qgsrect.cpp

@@ -132,7 +132,12 @@ void QgsRect::expand( double scaleFactor, const QgsPoint * cp )
 QgsRect QgsRect::intersect( QgsRect * rect ) const
 {
   QgsRect intersection = QgsRect();
-
+  //If they don't actually intersect an empty QgsRect should be returned
+  if ( !rect || !intersects( *rect ) )
+  {
+    return intersection;
+  }
+  
   intersection.setXMinimum( xmin > rect->xMin() ? xmin : rect->xMin() );
   intersection.setXMaximum( xmax < rect->xMax() ? xmax : rect->xMax() );
   intersection.setYMinimum( ymin > rect->yMin() ? ymin : rect->yMin() );