Example (JKQTPlotter): Line Graph with Different Symbols and Line Styles

This project (see ./examples/symbols_and_styles/) simply creates a JKQTPlotter widget (as a new window) and adds a single line-graph (a sine-wave). Data is initialized from two QVector<double> objects.

The source code of the main application can be found in symbols_and_styles.cpp. Mainly several graphs are generated in a loop and then different symbol and line styles are applied to the graph (set by graph->setSymbolType() for the symbol and graph->setLineStyle() for the line style). The colors are set automtically from an internal default palette. The main loop looks like this:

QVector<Qt::PenStyle> pens {Qt::NoPen, Qt::SolidLine, Qt::DashLine, Qt::DotLine, Qt::DashDotLine, Qt::DashDotDotLine };
int ipen=0;
for (int symbolID=0; symbolID<=JKQTPMaxSymbolID; symbolID++) {
    // generate some plot data
    QVector<double> Y;
    for (auto& xx: X) {
        Y<<sin(xx)+static_cast<double>(symbolID)*1.5;
    }
 
    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(symbolID)));
 
    // set symbol + pen style and color
    graph->setSymbolType(static_cast<JKQTPGraphSymbols>(symbolID));
    graph->setLineStyle(pens[ipen]);
    // set symbol size
    graph->setSymbolSize(14);
    // set width of symbol lines
    graph->setSymbolLineWidth(1.5);
    // set width of graph line
    graph->setLineWidth(1);
    
    // graph title is made from symbol+penstyle
    graph->setTitle(JKQTPGraphSymbols2NameString(static_cast<JKQTPGraphSymbols>(graph->getSymbolType()))+QString(", ")+jkqtp_QPenStyle2String(graph->getLineStyle()));
 
    // add the graph to the plot, so it is actually displayed
    plot.addGraph(graph);
 
    ipen++;
    if (ipen>=pens.size()) ipen=0;
}

In addition to the symbol type and line style, you can also alter the size of the symbols (graph->setSymbolSize(14)), the line-width used to draw them (graph->setSymbolLineWidth(1.5)) and the line width of the graph line (graph->setLineWidth(1)). If you want to switch off the line altogether, use graph->setDrawLine(false).

Note: There are additional, more advanced options for styling the graphs. See the example Advanced Line and Fill Styling for details.

The result looks like this: