Gradient Multi-Bar Chart

The following is the command line version of the code in "cppdemo/gradientmultibar". 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 bar chart
    double data0[] = {100, 125, 245, 147, 67};
    const int data0_size = (int)(sizeof(data0)/sizeof(*data0));
    double data1[] = {85, 156, 179, 211, 123};
    const int data1_size = (int)(sizeof(data1)/sizeof(*data1));
    double data2[] = {97, 87, 56, 267, 157};
    const int data2_size = (int)(sizeof(data2)/sizeof(*data2));
    const char* labels[] = {"Mon", "Tue", "Wed", "Thur", "Fri"};
    const int labels_size = (int)(sizeof(labels)/sizeof(*labels));

    // Create a XYChart object of size 540 x 375 pixels
    XYChart* c = new XYChart(540, 375);

    // Add a title to the chart using 18pt Times Bold Italic font
    c->addTitle("Average Weekly Network Load", "Times New Roman Bold Italic", 18);

    // Set the plotarea at (50, 55) and of 440 x 280 pixels in size. Use a vertical gradient color
    // from grey (888888) to black (000000) as background. Set border and grid lines to white
    // (ffffff).
    c->setPlotArea(50, 55, 440, 280, c->linearGradientColor(0, 55, 0, 335, 0x888888, 0x000000), -1,
        0xffffff, 0xffffff);

    // Add a legend box at (50, 25) using horizontal layout. Use 10pt Arial Bold as font, with
    // transparent background.
    c->addLegend(50, 25, false, "Arial Bold", 10)->setBackground(Chart::Transparent);

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

    // Draw the ticks between label positions (instead of at label positions)
    c->xAxis()->setTickOffset(0.5);

    // 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
    c->yAxis()->setTitle("Throughput (MBytes Per Hour)");

    // Add a multi-bar layer with 3 data sets and 4 pixels 3D depth
    BarLayer* layer = c->addBarLayer(Chart::Side, 4);
    layer->addDataSet(DoubleArray(data0, data0_size), 0x66aaee, "Server #1");
    layer->addDataSet(DoubleArray(data1, data1_size), 0xeebb22, "Server #2");
    layer->addDataSet(DoubleArray(data2, data2_size), 0xcc0000, "Server #3");

    // Set bar border to transparent. Use bar gradient lighting with light intensity from 0.75 to
    // 1.75.
    layer->setBorderColor(Chart::Transparent, Chart::barLighting(0.75, 1.75));

    // Configure the bars within a group to touch each others (no gap)
    layer->setBarGap(0.2, Chart::TouchBar);

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

    //free up resources
    delete c;

    return 0;
}