2D Donut Shading

The following is the command line version of the code in "cppdemo/donutshading". 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"

void createChart(int chartIndex, const char *filename)
{
    // The data for the pie chart
    double data[] = {18, 30, 20, 15};
    const int data_size = (int)(sizeof(data)/sizeof(*data));

    // The colors to use for the sectors
    int colors[] = {0x66aaee, 0xeebb22, 0xbbbbbb, 0x8844ff};
    const int colors_size = (int)(sizeof(colors)/sizeof(*colors));

    // Create a PieChart object of size 200 x 220 pixels. Use a vertical gradient color from blue
    // (0000cc) to deep blue (000044) as background. Use rounded corners of 16 pixels radius.
    PieChart* c = new PieChart(200, 220);
    c->setBackground(c->linearGradientColor(0, 0, 0, c->getHeight(), 0x0000cc, 0x000044));
    c->setRoundedFrame(0xffffff, 16);

    // Set donut center at (100, 120), and outer/inner radii as 80/40 pixels
    c->setDonutSize(100, 120, 80, 40);

    // Set the pie data
    c->setData(DoubleArray(data, data_size));

    // Set the sector colors
    c->setColors(Chart::DataColor, IntArray(colors, colors_size));

    // Demonstrates various shading modes
    if (chartIndex == 0) {
        c->addTitle("Default Shading", "bold", 12, 0xffffff);
    } else if (chartIndex == 1) {
        c->addTitle("Local Gradient", "bold", 12, 0xffffff);
        c->setSectorStyle(Chart::LocalGradientShading);
    } else if (chartIndex == 2) {
        c->addTitle("Global Gradient", "bold", 12, 0xffffff);
        c->setSectorStyle(Chart::GlobalGradientShading);
    } else if (chartIndex == 3) {
        c->addTitle("Concave Shading", "bold", 12, 0xffffff);
        c->setSectorStyle(Chart::ConcaveShading);
    } else if (chartIndex == 4) {
        c->addTitle("Rounded Edge", "bold", 12, 0xffffff);
        c->setSectorStyle(Chart::RoundedEdgeShading);
    } else if (chartIndex == 5) {
        c->addTitle("Radial Gradient", "bold", 12, 0xffffff);
        c->setSectorStyle(Chart::RadialShading);
    } else if (chartIndex == 6) {
        c->addTitle("Ring Shading", "bold", 12, 0xffffff);
        c->setSectorStyle(Chart::RingShading);
    }

    // Disable the sector labels by setting the color to Transparent
    c->setLabelStyle("", 8, Chart::Transparent);

    // Output the chart
    c->makeChart(filename);

    //free up resources
    delete c;

}

int main(int argc, char *argv[])
{
    createChart(0, "donutshading0.png");
    createChart(1, "donutshading1.png");
    createChart(2, "donutshading2.png");
    createChart(3, "donutshading3.png");
    createChart(4, "donutshading4.png");
    createChart(5, "donutshading5.png");
    createChart(6, "donutshading6.png");
    return 0;
}