C++ QwtPlotMarker::xAxis方法代码示例

//! Redraw grid, curves, and markers. The draw code
//  does not clear clipRegion prior to painting.
//  \param p painter used for drawing
void QwtPlot::drawCanvas(QPainter *p)
{
    QwtDiMap map[axisCnt];
    for ( int axis = 0; axis < axisCnt; axis++ )
        map[axis] = canvasMap(axis);

    QRect rect = d_canvas->contentsRect();

    //
    // draw grid
    //
    if ( d_grid.enabled() &&
         axisEnabled( d_grid.xAxis() ) &&
         axisEnabled( d_grid.yAxis() ) )
    {
        d_grid.draw(p, rect, map[d_grid.xAxis()], map[d_grid.yAxis()]);
    }

    //
    //  draw curves
    //

    QIntDictIterator<QwtPlotCurve> itc(*d_curves);
    for (QwtPlotCurve *curve = itc.toFirst(); curve != 0; curve = ++itc )
    {
      if ( curve->enabled() &&
           axisEnabled( curve->xAxis() ) &&
           axisEnabled( curve->yAxis() ) )
      {
            curve->draw(p, map[curve->xAxis()], map[curve->yAxis()]);
      }
    }

    //
    // draw markers
    //

    QIntDictIterator<QwtPlotMarker> itm(*d_markers);
    for (QwtPlotMarker *marker = itm.toFirst(); marker != 0; marker = ++itm )
    {
        if ( marker->enabled() && axisEnabled( marker->xAxis() ) &&
               axisEnabled( marker->yAxis() ) )
        {
            marker->draw(p,
                map[marker->xAxis()].transform(marker->xValue()),
                map[marker->yAxis()].transform(marker->yValue()),
                rect);
        }
    }
}

// Select the point at a position.
void XtalOptPlot::select(const QPoint& pos)
{
  QwtPlotMarker* selection = nullptr;

  // Must be within 10 pixels at least
  double dist = 10.0;

  const QwtPlotItemList& itmList = itemList();
  for (QwtPlotItemIterator it = itmList.begin(); it != itmList.end(); ++it) {
    if ((*it)->rtti() == QwtPlotItem::Rtti_PlotMarker) {
      QwtPlotMarker* m = static_cast<QwtPlotMarker*>(*it);
      // We have to map the plot coordinates onto widget coordinates before
      // comparing
      const QwtScaleMap& xMap = canvasMap(m->xAxis());
      const QwtScaleMap& yMap = canvasMap(m->yAxis());
      double mx = xMap.transform(m->xValue());
      double my = yMap.transform(m->yValue());
      double d = distance(QPointF(mx, my), pos);
      if (d < dist) {
        selection = m;
        dist = d;
      }
    }
  }

  selectMarker(selection);
}

/*!
  \return the x axis to which a marker is attached
  \param key Marker key
*/
int QwtPlot::markerXAxis(long key) const
{
    QwtPlotMarker *m = d_markers->find(key);
    if (m)
        return m->xAxis();
    else
        return -1;
    
}

void QwtPlot::drawCanvasItems(QPainter *painter, const QRect &rect, 
        const QwtArray<QwtDiMap> &map, const QwtPlotPrintFilter &pfilter) const
{
    //
    // draw grid
    //
    if ( pfilter.options() & QwtPlotPrintFilter::PrintGrid )
    {
        if ( d_grid->enabled() )
        {
            d_grid->draw(painter, rect, 
                map[d_grid->xAxis()], map[d_grid->yAxis()]);
        }
    }

    //
    //  draw curves
    //
    QwtPlotCurveIterator itc = curveIterator();
    for (QwtPlotCurve *curve = itc.toFirst(); curve != 0; curve = ++itc )
    {
        if ( curve->enabled() )
        {
            curve->draw(painter, 
                map[curve->xAxis()], map[curve->yAxis()]);
        }
    }

    //
    // draw markers
    //
    QwtPlotMarkerIterator itm = markerIterator();
    for (QwtPlotMarker *marker = itm.toFirst(); marker != 0; marker = ++itm )
    {
        if ( marker->enabled() )
        {
            marker->draw(painter,
                map[marker->xAxis()].transform(marker->xValue()),
                map[marker->yAxis()].transform(marker->yValue()),
                rect);
        }
    }
}

/*!
  \brief Find the marker which is closest to a given point.
  \param xpos
  \param ypos coordinates of a point in the plotting region
  \retval dist Distance in points between the marker and the specified point.
  \return Key of the closest marker or 0 if no marker was found
*/
long QwtPlot::closestMarker(int xpos, int ypos, int &dist) const
{
    QwtDiMap map[axisCnt];
    for ( int axis = 0; axis < axisCnt; axis++ )
        map[axis] = canvasMap(axis);

    long rv = 0;
    double dmin = 1.0e10;
    
    QwtPlotMarkerIterator itm = markerIterator();
    for (QwtPlotMarker *m = itm.toFirst(); m != 0; m = ++itm )
    {
        double cx = map[m->xAxis()].xTransform(m->xValue());
        double cy = map[m->yAxis()].xTransform(m->yValue());

        if (m->lineStyle() == QwtMarker::HLine)
        {
            if (m->symbol().style() == QwtSymbol::None)
               cx = double(xpos);
        }
        else if (m->lineStyle() == QwtMarker::VLine)
        {
            if (m->symbol().style() == QwtSymbol::None)
               cy = double(ypos);
        }
        
        double f = qwtSqr(cx - double(xpos)) + qwtSqr(cy - double(ypos));
        if (f < dmin)
        {
            dmin = f;
            rv = itm.currentKey();
        }
    }

    dist = int(sqrt(dmin));
    return rv;
}