Example (JKQTPlotter): Filled Graphs with Error Indicators

This project (see filledgraphs_errors shows how to draw filled graphs with different styles of error indicators.

The source code of the main application is (see filledgraphs_errors.cpp:

// 1. create a plotter window and get a pointer to the internal datastore (for convenience)
JKQTPlotter plot;
JKQTPDatastore* ds=plot.getDatastore();
 
// 2. now we create three columns for key and value
size_t columnK=ds->addLinearColumn(9, 0.1*JKQTPSTATISTICS_PI, 1.0*JKQTPSTATISTICS_PI,"k");
size_t columnK2=ds->addLinearColumn(9, 1.1*JKQTPSTATISTICS_PI, 2.0*JKQTPSTATISTICS_PI,"k2");
size_t columnK3=ds->addLinearColumn(9, 2.1*JKQTPSTATISTICS_PI, 3.0*JKQTPSTATISTICS_PI,"k2");
size_t columnV=ds->addColumnCalculatedFromColumn(columnK, [](double x) { return sin(x); }, "v");
size_t columnV2=ds->addColumnCalculatedFromColumn(columnK2, [](double x) { return -sin(x); }, "v2");
size_t columnV3=ds->addColumnCalculatedFromColumn(columnK3, [](double x) { return sin(x); }, "v3");
size_t columnE=ds->addColumnCalculatedFromColumn(columnV, [](double x) { return 0.2*x; }, "error");
size_t columnE2=ds->addColumnCalculatedFromColumn(columnV2, [](double x) { return 0.2*x; }, "error");
size_t columnE3=ds->addColumnCalculatedFromColumn(columnV3, [](double x) { return 0.2*x; }, "error");
 
// 3. create a graph in the plot, which plots the dataset with symmetric:
JKQTPFilledCurveXErrorGraph* graph1=new JKQTPFilledCurveXErrorGraph(&plot);
graph1->setKeyColumn(columnK);
graph1->setValueColumn(columnV);
graph1->setValueErrorColumn(columnE);
// set error indicator style
graph1->setValueErrorStyle(JKQTPErrorBars);
graph1->setTitle(QObject::tr("JKQTPErrorBars"));
plot.addGraph(graph1);
 
// 4. create a second graph in the plot, which plots the second dataset with outer error bars only:
JKQTPFilledCurveXErrorGraph* graph2=new JKQTPFilledCurveXErrorGraph(&plot);
graph2->setKeyColumn(columnK2);
graph2->setValueColumn(columnV2);
graph2->setValueErrorColumn(columnE2);
// set error indicator style
graph2->setValueErrorStyle(JKQTPErrorPolygons);
graph2->setTitle(QObject::tr("JKQTPErrorPolygons"));
plot.addGraph(graph2);
 
// 5. create a third graph in the plot, which plots the second dataset with outer error bars only:
JKQTPFilledCurveXErrorGraph* graph3=new JKQTPFilledCurveXErrorGraph(&plot);
graph3->setKeyColumn(columnK3);
graph3->setValueColumn(columnV3);
graph3->setValueErrorColumn(columnE3);
// set error indicator style
graph3->setValueErrorStyle(JKQTPErrorLines);
graph3->setTitle(QObject::tr("JKQTPErrorLines"));
plot.addGraph(graph3);
 
 
// 6 autoscale the plot so the graph is contained
plot.zoomToFit();
 
// 7. show plotter and make it a decent size
plot.getPlotter()->setKeyPosition(JKQTPKeyInsideBottomLeft);
plot.setWindowTitle(title);
plot.show();
plot.resize(400,400);

The result looks like this:

In order to draw horizontal error bars, you have to use JKQTPFilledCurveYErrorGraph instead of JKQTPFilledCurveXErrorGraph: