Symbol Line Chart (2)

This example demonstrates using symbols to represent data points and using gradient color for plot area background.

The gradient plot area background is configured by using BaseChart.linearGradientColor to define the gradient color, then use XYChart.setPlotArea to apply it to the plot area.
The XYChart.setPlotArea also sets the plot area border and grid line colors to white.
Use BaseChart.addLegend to add a legend at the top of the chart.
Use DataSet.setDataSymbol to configure symbols for the data points.
Set the line width for all lines in the layer using Layer.setLineWidth. (To set the line width for one particular line, use DataSet.setLineWidth.)

The following is the command line version of the code in "cppdemo/symbolline2". 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 data0[] = {42, 49, 33, 38, 64, 56, 29, 41, 44, 57, 59, 42};
    const int data0_size = (int)(sizeof(data0)/sizeof(*data0));
    double data1[] = {65, 75, 47, 34, 42, 49, 73, 62, 90, 69, 66, 78};
    const int data1_size = (int)(sizeof(data1)/sizeof(*data1));
    double data2[] = {36, 28, 25, 28, 38, 20, 22, 30, 25, 33, 30, 24};
    const int data2_size = (int)(sizeof(data2)/sizeof(*data2));
    const char* labels[] = {"Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug", "Sep", "Oct",
        "Nov", "Dec"};
    const int labels_size = (int)(sizeof(labels)/sizeof(*labels));

    // Create a XYChart object of size 600 x 375 pixels
    XYChart* c = new XYChart(600, 375);

    // Add a title to the chart using 18pt Times Bold Italic font
    c->addTitle("Product Line Global Revenue", "Times New Roman Bold Italic", 18);

    // Set the plotarea at (50, 55) and of 500 x 280 pixels in size. Use a vertical gradient color
    // from light blue (f9f9ff) to sky blue (aaccff) as background. Set border to transparent and
    // grid lines to white (ffffff).
    c->setPlotArea(50, 55, 500, 280, c->linearGradientColor(0, 55, 0, 335, 0xf9fcff, 0xaaccff), -1,
        Chart::Transparent, 0xffffff);

    // Add a legend box at (50, 28) using horizontal layout. Use 10pt Arial Bold as font, with
    // transparent background.
    c->addLegend(50, 28, false, "Arial Bold", 10)->setBackground(Chart::Transparent);

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

    // Set y-axis tick density to 30 pixels. ChartDirector auto-scaling will use this as the
    // guideline when putting ticks on the y-axis.
    c->yAxis()->setTickDensity(30);

    // Set axis label style to 8pt Arial Bold
    c->xAxis()->setLabelStyle("Arial Bold", 8);
    c->yAxis()->setLabelStyle("Arial Bold", 8);

    // Set axis line width to 2 pixels
    c->xAxis()->setWidth(2);
    c->yAxis()->setWidth(2);

    // Add axis title using 10pt Arial Bold Italic font
    c->yAxis()->setTitle("Revenue in USD millions", "Arial Bold Italic", 10);

    // Add a line layer to the chart
    LineLayer* layer = c->addLineLayer();

    // Set the line width to 3 pixels
    layer->setLineWidth(3);

    // Add the three data sets to the line layer, using circles, diamands and X shapes as symbols
    layer->addDataSet(DoubleArray(data0, data0_size), 0xff0000, "Quantum Computer")->setDataSymbol(
        Chart::CircleSymbol, 9);
    layer->addDataSet(DoubleArray(data1, data1_size), 0x00ff00, "Atom Synthesizer")->setDataSymbol(
        Chart::DiamondSymbol, 11);
    layer->addDataSet(DoubleArray(data2, data2_size), 0xff6600, "Proton Cannon")->setDataSymbol(
        Chart::Cross2Shape(), 11);

    // Output the chart
    c->makeChart("symbolline2.png");

    //free up resources
    delete c;

    return 0;
}