Simple Line Chart

This example demonstrates the basic steps in creating line charts.

Create an XYChart object using XYChart.XYChart.
Specify the plot area of the chart using XYChart.setPlotArea. The plot area is the rectangle bounded by the x and y axes. You should leave some margin on the outside of the plot area for axis labels, chart titles, etc.
Specify the labels on the x-axis using Axis.setLabels.
A line chart may contain many points and therefore many x-axis labels. In this example, Axis.setLabelStep is used to specify showing only a subset of the labels on the x-axis to avoid over-crowding.
Add a line layer and specify the data for the line using XYChart.addLineLayer.
Pass the chart to the CChartViewer for display using CChartViewer.setChart (MFC version) or QChartViewer.setChart (Qt version), or generate the chart as an image file using BaseChart.makeChart (Command Line version).
Generate tool tips for the chart using BaseChart.getHTMLImageMap. (MFC/Qt version)

The following is the command line version of the code in "cppdemo/simpleline". The MFC version of the code is in "mfcdemo/mfcdemo". The Qt Widgets version of the code is in "qtdemo/qtdemo". The QML/Qt Quick version of the code is in "qmldemo/qmldemo".

#include "chartdir.h"

int main(int argc, char *argv[])
{
    // The data for the line chart
    double data[] = {30, 28, 40, 55, 75, 68, 54, 60, 50, 62, 75, 65, 75, 91, 60, 55, 53, 35, 50, 66,
        56, 48, 52, 65, 62};
    const int data_size = (int)(sizeof(data)/sizeof(*data));

    // The labels for the line chart
    const char* labels[] = {"0", "1", "2", "3", "4", "5", "6", "7", "8", "9", "10", "11", "12",
        "13", "14", "15", "16", "17", "18", "19", "20", "21", "22", "23", "24"};
    const int labels_size = (int)(sizeof(labels)/sizeof(*labels));

    // Create a XYChart object of size 250 x 250 pixels
    XYChart* c = new XYChart(250, 250);

    // Set the plotarea at (30, 20) and of size 200 x 200 pixels
    c->setPlotArea(30, 20, 200, 200);

    // Add a line chart layer using the given data
    c->addLineLayer(DoubleArray(data, data_size));

    // Set the labels on the x axis.
    c->xAxis()->setLabels(StringArray(labels, labels_size));

    // Display 1 out of 3 labels on the x-axis.
    c->xAxis()->setLabelStep(3);

    // Output the chart
    c->makeChart("simpleline.png");

    //free up resources
    delete c;

    return 0;
}