JKQTPlotter trunk/v5.0.0
an extensive Qt5+Qt6 Plotter framework (including a feature-richt plotter widget, a speed-optimized, but limited variant and a LaTeX equation renderer!), written fully in C/C++ and without external dependencies
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Example (JKQTPlotter): Simple line-graph with error bars

This project (see ./examples/symbols_and_errors/) simply creates a JKQTPlotter widget (as a new window) and adds a single line-graph (a sine-wave) that has y-errorbars. In addition, this example shows how to change some of the axis properties and how to use LaTeX markup to format axis labels (can actually be used for all labels in JKQTPlotter). Also, in comparison to the last example, here we initialize the data from C-type arrays (double*), instead of QVector<double> objects.

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

#include <QApplication>
#include "jkqtplotter/jkqtplotter.h"
// number of datapoints:
#define Ndata 10
int main(int argc, char* argv[])
{
QApplication app(argc, argv);
// 1. create a plotter window and get a pointer to the internal datastore (for convenience)
// 2. now we create data for a simple plot (a sine curve with lin. increasing errors)
double X[Ndata], Y[Ndata], YERROR[Ndata];
for (int i=0; i<Ndata; i++) {
X[i]=double(i)/double(Ndata)*2.0*M_PI;
Y[i]=sin(X[i]);
YERROR[i]=0.2+double(i)/double(Ndata)*0.25;
}
// 3. make data available to JKQTPlotter by adding it to the internal datastore.
// Note: In this step the data is copied (of not specified otherwise), so you can
// reuse X and Y afterwards!
// the variables columnX and columnY will contain the internal column ID of the newly
// created columns with names "x" and "y" and the (copied) data from X and Y.
size_t columnX=ds->addCopiedColumn(X, Ndata, "x");
size_t columnY=ds->addCopiedColumn(Y, Ndata, "y");
size_t columnYE=ds->addCopiedColumn(YERROR, Ndata, "y-error");
// 4. create a graph in the plot, which plots the dataset X/Y:
graph1->setXColumn(columnX);
graph1->setYColumn(columnY);
graph1->setYErrorColumn(columnYE);
graph1->setSymbolType(JKQTPFilledStar); // set symbol style
graph1->setYErrorStyle(JKQTPErrorBars); // set error indicator type
graph1->setDrawLine(false); // don't draw a line
graph1->setTitle(QObject::tr("sine graph"));
// 5. add the graph to the plot, so it is actually displayed
plot.addGraph(graph1);
// 6. hide 0-lines
plot.getXAxis()->setShowZeroAxis(false);
plot.getYAxis()->setShowZeroAxis(false);
// 7. set some axis properties (we use LaTeX for nice equation rendering)
plot.getXAxis()->setAxisLabel(QObject::tr("x-axis $x$ [mm]"));
plot.getYAxis()->setAxisLabel(QObject::tr("\\textbf{\\color{red}{y-axis} $\\left(y=\\sin(x)\\pm(0.2+0.25\\cdot x)\\right)$ [A.U.]}"));
plot.getYAxis()->setLabelFontSize(12); // large x-axis label
plot.getYAxis()->setTickLabelFontSize(10); // and larger y-axis tick labels
// 8. autoscale the plot so the graph is contained
plot.zoomToFit();
// show plotter and make it a decent size
plot.show();
plot.resize(600,400);
return app.exec();
}
void setLabelFontSize(double __value)
fontsize of the axis labels
void setShowZeroAxis(bool __value)
indicates whether to draw a thick axis line at x=0 (zero axis)
void setTickLabelFontSize(double __value)
fontsize of the axis tick labels
void setAxisLabel(const QString &__value)
axis label of the axis
This class manages data columns (with entries of type double ), used by JKQTPlotter/JKQTBasePlotter t...
Definition jkqtpdatastorage.h:282
size_t addCopiedColumn(TIterator first, TIterator last, const QString &name=QString(""))
add one column to the datastore. It will be filled with the values from first ... last
Definition jkqtpdatastorage.h:871
void setSymbolType(JKQTPGraphSymbols __value)
set the type of the graph symbol
virtual void setTitle(const QString &__value)
sets the title of the plot (for display in key!).
void setYColumn(int __value)
the column that contains the y-component of the datapoints
void setXColumn(int __value)
the column that contains the x-component of the datapoints
This implements xy line plots with x and y error indicators.
Definition jkqtplines.h:112
void setDrawLine(bool __value)
indicates whether to draw a line or not
void setYErrorColumn(int __value)
the column that contains the error of the x-component of the datapoints
void setYErrorStyle(JKQTPErrorPlotstyle __value)
how to draw the errors (if available) of the x-value
plotter widget for scientific plots (uses JKQTBasePlotter to do the actual drawing)
Definition jkqtplotter.h:364
void zoomToFit(bool zoomX=true, bool zoomY=true, bool includeX0=false, bool includeY0=false, double scaleX=1.05, double scaleY=1.05)
this method zooms the graph so that all plotted datapoints are visible.
Definition jkqtplotter.h:1039
JKQTPVerticalAxisBase * getYAxis(JKQTPCoordinateAxisRef axis=JKQTPPrimaryAxis)
returns the y-axis objet of the plot
Definition jkqtplotter.h:713
size_t addGraph(JKQTPPlotElement *gr)
Definition jkqtplotter.h:784
JKQTPDatastore * getDatastore()
returns a pointer to the datastore used by this object
Definition jkqtplotter.h:611
JKQTPHorizontalAxisBase * getXAxis(JKQTPCoordinateAxisRef axis=JKQTPPrimaryAxis)
returns the x-axis objet of the plot
Definition jkqtplotter.h:711
@ JKQTPErrorBars
error bars for each data point
Definition jkqtptools.h:711
@ JKQTPFilledStar
a filled diamond
Definition jkqtpdrawingtools.h:157

The result looks like this:

symbols_and_errors