Plot Screenshots: Simple Demo


  // add two new graphs and set their look:
  customPlot->graph(0)->setPen(QPen(Qt::blue)); // line color blue for first graph
  customPlot->graph(0)->setBrush(QBrush(QColor(0, 0, 255, 20))); // first graph will be filled with translucent blue
  customPlot->graph(1)->setPen(QPen(Qt::red)); // line color red for second graph
  // generate some points of data (y0 for first, y1 for second graph):
  QVector<double> x(251), y0(251), y1(251);
  for (int i=0; i<251; ++i)
    x[i] = i;
    y0[i] = qExp(-i/150.0)*qCos(i/10.0); // exponentially decaying cosine
    y1[i] = qExp(-i/150.0);              // exponential envelope
  // configure right and top axis to show ticks but no labels:
  // (see QCPAxisRect::setupFullAxesBox for a quicker method to do this)
  // make left and bottom axes always transfer their ranges to right and top axes:
  connect(customPlot->xAxis, SIGNAL(rangeChanged(QCPRange)), customPlot->xAxis2, SLOT(setRange(QCPRange)));
  connect(customPlot->yAxis, SIGNAL(rangeChanged(QCPRange)), customPlot->yAxis2, SLOT(setRange(QCPRange)));
  // pass data points to graphs:
  customPlot->graph(0)->setData(x, y0);
  customPlot->graph(1)->setData(x, y1);
  // let the ranges scale themselves so graph 0 fits perfectly in the visible area:
  // same thing for graph 1, but only enlarge ranges (in case graph 1 is smaller than graph 0):
  // Note: we could have also just called customPlot->rescaleAxes(); instead
  // Allow user to drag axis ranges with mouse, zoom with mouse wheel and select graphs by clicking:
  customPlot->setInteractions(QCP::iRangeDrag | QCP::iRangeZoom | QCP::iSelectPlottables);