class RArrow
{
   public:
     RArrow();

     void raDrawArrow( QPainter *p );

     void raSetArrowHead();
     void raSetArrowLine();

     void raSetArrowHead2();
     void raSetArrowLine2();

   public:
     QPointF raArrowPoints[ 10 ];

     QPointF raStartPoint;
     QPointF raEndPoint;

     double raLineWidth;

     double raHeadWidth;
     double raHeadHeight;

     QColor raBorderColor;
     QColor raFillColor;
     double raBorderThickness;

     bool twoSided;
};

//=================================================================================================
RArrow::RArrow()
{
   raStartPoint = QPoint( -1, -1 );
   raEndPoint = QPoint( -1, -1 );
   raLineWidth = 0;
   raHeadHeight = 0;
   raHeadWidth = 0;
   raBorderThickness = 0;
   twoSided = false;

   for (int i = 0; i < 10; ++i)
     raArrowPoints[i] = QPointF( -1, -1 );
}
//=================================================================================================
void RArrow::raSetArrowHead()
{
   double x1 = raStartPoint.x();
   double y1 = raStartPoint.y();
   double x2 = raEndPoint.x();
   double y2 = raEndPoint.y();

   double distance = sqrt( pow( x2 - x1, 2 ) + pow( y2 - y1, 2 ) );

   double dx = x2 + (x1 - x2) * raHeadHeight / distance;
   double dy = y2 + (y1 - y2) * raHeadHeight / distance;

   double k = raHeadWidth / raHeadHeight;

   double x2o = x2 - dx;
   double y2o = dy - y2;

   double x3 = y2o * k + dx;
   double y3 = x2o * k + dy;

   double x4 = dx - y2o * k;
   double y4 = dy - x2o * k;

   raArrowPoints[0] = QPointF( x4, y4 );
   raArrowPoints[1] = QPointF( x2, y2 );
   raArrowPoints[2] = QPointF( x3, y3 );
}
//=================================================================================================
void RArrow::raSetArrowLine()
{
   double x1 = raStartPoint.x();
   double y1 = raStartPoint.y();
   double x2 = (raArrowPoints[0].x() + raArrowPoints[2].x()) / 2.0;
   double y2 = (raArrowPoints[0].y() + raArrowPoints[2].y()) / 2.0;

   double k = raLineWidth / sqrt( pow( x2 - x1, 2 ) + pow( y2 - y1, 2 ) );

   double x2o = x2 - x1;
   double y2o = y1 - y2;

   double x3 = y2o * k + x1;
   double y3 = x2o * k + y1;

   double x4 = x1 - y2o * k;
   double y4 = y1 - x2o * k;

   double x1o = x1 - x2;
   double y1o = y2 - y1;

   double x5 = y1o * k + x2;
   double y5 = x1o * k + y2;

   double x6 = x2 - y1o * k;
   double y6 = y2 - x1o * k;

   raArrowPoints[4] = QPointF( x3, y3 );
   raArrowPoints[5] = QPointF( x4, y4 );
   raArrowPoints[6] = QPointF( x5, y5 );
   raArrowPoints[3] = QPointF( x6, y6 );
}
//=================================================================================================
void RArrow::raSetArrowHead2()
{
   double x1 = raEndPoint.x();
   double y1 = raEndPoint.y();
   double x2 = raStartPoint.x();
   double y2 = raStartPoint.y();

   double distance = sqrt( pow( x2 - x1, 2 ) + pow( y2 - y1, 2 ) );

   double dx = x2 + (x1 - x2) * raHeadHeight / distance;
   double dy = y2 + (y1 - y2) * raHeadHeight / distance;

   double k = raHeadWidth / raHeadHeight;

   double x2o = x2 - dx;
   double y2o = dy - y2;

   double x3 = y2o * k + dx;
   double y3 = x2o * k + dy;

   double x4 = dx - y2o * k;
   double y4 = dy - x2o * k;

   raArrowPoints[5] = QPointF( x4, y4 );
   raArrowPoints[6] = QPointF( x2, y2 );
   raArrowPoints[7] = QPointF( x3, y3 );
}
//=================================================================================================
void RArrow::raSetArrowLine2()
{
   double x1 = (raArrowPoints[0].x() + raArrowPoints[2].x()) / 2.0;
   double y1 = (raArrowPoints[0].y() + raArrowPoints[2].y()) / 2.0;
   double x2 = (raArrowPoints[5].x() + raArrowPoints[7].x()) / 2.0;
   double y2 = (raArrowPoints[5].y() + raArrowPoints[7].y()) / 2.0;

   double k = raLineWidth / sqrt( pow( x2 - x1, 2 ) + pow( y2 - y1, 2 ) );

   double x2o = x2 - x1;
   double y2o = y1 - y2;

   double x3 = y2o * k + x1;
   double y3 = x2o * k + y1;

   double x4 = x1 - y2o * k;
   double y4 = y1 - x2o * k;

   double x1o = x1 - x2;
   double y1o = y2 - y1;

   double x5 = y1o * k + x2;
   double y5 = x1o * k + y2;

   double x6 = x2 - y1o * k;
   double y6 = y2 - x1o * k;

   raArrowPoints[9] = QPointF( x3, y3 );
   raArrowPoints[3] = QPointF( x4, y4 );
   raArrowPoints[4] = QPointF( x5, y5 );
   raArrowPoints[8] = QPointF( x6, y6 );
}
//=================================================================================================
void RArrow::raDrawArrow( QPainter *p )
{
   p->setPen( QPen( QBrush( raBorderColor ), raBorderThickness, Qt::SolidLine, Qt::RoundCap, Qt::RoundJoin ) );
   p->setBrush( QBrush( raFillColor ) );

   if (!twoSided)
   {
     raSetArrowHead();
     raSetArrowLine();
   }
   else
   {
     raSetArrowHead();
     raSetArrowHead2();
     raSetArrowLine2();
   }

   p->setRenderHint( QPainter::Antialiasing, true );

   if (!twoSided)
     p->drawPolygon( raArrowPoints, 7 );
   else
     p->drawPolygon( raArrowPoints, 10 );
}
//=================================================================================================

void LegendScene::drawForeground( QPainter *painter, const QRectF &/*rect*/ )
{
   painter->beginNativePainting();

   RArrow arrow;
   arrow.raStartPoint = QPointF( 10, 10 );
   arrow.raEndPoint = QPointF( 100, 100 );
   arrow.raHeadWidth = 5.0;
   arrow.raHeadHeight = 15.0;
   arrow.raBorderThickness = 2.0;
   arrow.raLineWidth = 2.0;
   arrow.raBorderColor = Qt::black;
   arrow.raFillColor = Qt::gray;
   arrow.twoSided = true;
   arrow.raDrawArrow( painter );

   painter->endNativePainting();
}