Example (JKQTPlotter): Simple impulse plots

This project (see ./examples/impulsesplot/) simply creates a JKQTPlotter widget (as a new window) and adds a single impulse graph. The source code of the main application is (see impulsesplot.cpp.

First data for a curve is calculated and stored in QVector<double>:

QVector<double> X, Y;
for (int i=0; i<Ndata; i++) {
    const double xx=double(i)/double(Ndata)*6.0*M_PI;
    X << xx;
    Y << cos(xx)*exp(-xx/10.0);
}

... and finally the data is copied into the datastore

size_t columnX=ds->addCopiedColumn(X,  "x");
size_t columnY=ds->addCopiedColumn(Y,  "y");

Now an impulse graph object is generated and added to the plot:

  JKQTPImpulsesVerticalGraph* graph=new JKQTPImpulsesVerticalGraph(&plot);
  graph->setXColumn(columnX);
  graph->setYColumn(columnY);
graph->setLineWidth(2);
graph->setColor(QColor("red"));
  graph->setTitle(QObject::tr("$\\cos(x)\\cdot\\exp(-x/10)$"));
 
  plot.addGraph(graph);

The result looks like this:

There is an alternative class JKQTPImpulsesHorizontalGraph which draws horizontal impulse plots:

JKQTPImpulsesHorizontalGraph* graph=new JKQTPImpulsesHorizontalGraph(&plot);
graph->setYColumn(columnX);
graph->setXColumn(columnY);
graph->setLineWidth(2);
graph->setColor(QColor("blue"));
graph->setTitle(QObject::tr("$\\cos(x)\\cdot\\exp(-x/10)$"));

This code snippet results in a plot like this:

The classes JKQTPImpulsesVerticalGraph and JKQTPImpulsesHorizontalGraph also provide the ability to draw a symbol at the end of the impulse, e.g. using this code:

graph->setDrawSymbols(true);
graph->setSymbolType(JKQTPGraphSymbols::JKQTPFilledStar);

This code snippet results in a plot like this:

Finally you can move the baseline (i.e. the level, where the impulses start, which is typically x=0 or y=0) in the classes JKQTPImpulsesVerticalGraph and JKQTPImpulsesHorizontalGraph:

graph->setBaseline(0.25);

This code snippet results in a plot like this: