/** \example logaxes.cpp * Shows how to use logarithmic axes with JKQTPlotter * * \ref JKQTPlotterLogAxes */ #include #include "jkqtplotter/jkqtplotter.h" #include "jkqtplotter/graphs/jkqtpscatter.h" #include "jkqtplotter/graphs/jkqtpgeometric.h" #include "jkqtplotter/jkqtptools.h" #define sqr(x) ((x)*(x)) 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) JKQTPlotter plot; JKQTPDatastore* ds=plot.getDatastore(); // 2. now we create data a vector of x-values for a simple plot (resonance curve with different damping value D) // see https://en.wikipedia.org/wiki/Resonance QVector X; QVector D { 0.001, 0.1, 1, 10}; const int Ndata=500; // number of plot points in each curve for (int i=0; iaddCopiedColumn(X, "x"); // 3. now we make several plots for different values of D QVector pens {Qt::SolidLine, Qt::DashLine, Qt::DotLine, Qt::DashDotLine, Qt::DashDotDotLine }; for (int id=0; id Y; for (auto& xx: X) { Y<<1.0/sqrt(sqr(1-sqr(xx))+sqr(2*xx*D[id])); } JKQTPXYLineGraph* graph=new JKQTPXYLineGraph(&plot); // copy data into datastore and immediately set the yColumn graph->setXColumn(columnX); graph->setYColumn(ds->addCopiedColumn(Y, "y"+QString::number(id))); // don't use symbols graph->setSymbolType(JKQTPNoSymbol); // use one of different pens graph->setLineStyle(pens[id%pens.size()]); // set width of graph line graph->setLineWidth(1.5); // graph title is made from symbol+penstyle graph->setTitle(QString("$D=\\delta/\\omega_0=%1$").arg(D[id])); // add the graph to the plot, so it is actually displayed plot.addGraph(graph); } // 4. Also we add a text-element in the plot to show the plotted function // This element (JKQTPGeoText) is taken from the set of geometric elements // and is simply parametrized by a position (1.25/10) and the text to display. // In addition you can also set the font size (here to 15) // Use '$...$' around the actual math string to ensure rendering with a math font // (the internal renderer uses XITS fonts by default, which are free and auto-distributed // and loaded in the library). If you don't use the math-mode modifiers, the default // font of the other rendering text is used, which might not be suitable for // high-quality math rendering. plot.addGraph(new JKQTPGeoText(&plot, 1.25, 10, "$\\frac{A}{A_{stat}}=\\frac{1}{\\sqrt{\\left(1-\\eta^2\\right)^2+\\left(2{\\eta}D\\right)^2}}$", 15, QColor("black"))); // 5. set y-axis to logarithmic (x-axis would be analogous, but using `plot.getXAxis()`) plot.getYAxis()->setLogAxis(true); // now we set the number of label ticks to 9 (you give the count if minor between two majors, // so if you want ticks for 1,2,3,...,10,20,30,...,100... you need to use 9: plot.getYAxis()->setMinorTicks(9); // the minor grid is not shown by default. You can switch it on: plot.getYAxis()->setDrawMinorGrid(true); // usually axis ticks are shown as numbers 0.01, 0.1, 1, 10, ... You can also force the scientific // power-of-10 notation, using: plot.getYAxis()->setLabelType(JKQTPCALTexponent); // the number of digits in JKQTPCALTexponent determines which labels are drawn in standard-notation, // as compared to power-notation (e.g. if set to 1, the labels 0.1=10^{-1}, 1, 10 are shown in // standard notation, the rest in power-notation. This tweak improves readability) plot.getYAxis()->setLabelDigits(0); // minor tick labels are usually not displayed, but you can switch them on, using //plot.getYAxis()->setMinorTickLabelsEnabled(true); // the axis font sizes can be set with: plot.getYAxis()->setTickLabelFontSize(10); // axis tick labels plot.getYAxis()->setMinorTickLabelFontSize(7); // minor axis tick labels plot.getYAxis()->setLabelFontSize(14); // axis label size plot.getXAxis()->setTickLabelFontSize(10); // axis tick labels plot.getXAxis()->setMinorTickLabelFontSize(7); // minor axis tick labels plot.getXAxis()->setLabelFontSize(14); // axis label size // ... and finally set axis labels (using LaTeX notation and $...$ to improve rendering) plot.getYAxis()->setAxisLabel("Amplitude $A/A_{stat}$"); plot.getXAxis()->setAxisLabel("relative driving frequency $\\eta=\\omega/\\omega_0$"); // 6. autoscale the plot so the graph is contained plot.zoomToFit(); // 7. show plotter and make it a decent size plot.show(); plot.resize(700,500); return app.exec(); }