ChartDirector 6.0 (C++ Edition)

Polar Spline Chart




This example demonstrates polar spline line and polar spline area.

The polar spline line is created using PolarChart.addSplineLineLayer. The polar spline area is created using PolarChart.addSplineAreaLayer.

Source Code Listing

[The following code is available in "cppdemo/polarspline". A MFC version of the code is available in "mfcdemo/mfcdemo" (Windows edition only). A QT version of the code is available in "qtdemo/qtdemo".]
#include "chartdir.h"

int main(int argc, char *argv[])
{
    // The data for the chart
    double data0[] = {5.1, 2.6, 1.5, 2.2, 5.1, 4.3, 4.0, 9.0, 1.7, 8.8, 9.9, 9.5, 9.4, 1.8, 2.1,
        2.3, 3.5, 7.7, 8.8, 6.1, 5.0, 3.1, 6.0, 4.3};
    double angles0[] = {0, 15, 30, 45, 60, 75, 90, 105, 120, 135, 150, 165, 180, 195, 210, 225, 240,
        255, 270, 285, 300, 315, 330, 345};

    double data1[] = {8.1, 2.5, 5, 5.2, 6.5, 8.5, 9, 7.6, 8.7, 6.4, 5.5, 5.4, 3.0, 8.7, 7.1, 8.8,
        7.9, 2.2, 5.0, 4.0, 1.5, 7.5, 8.3, 9.0};
    double angles1[] = {0, 15, 30, 45, 60, 75, 90, 105, 120, 135, 150, 165, 180, 195, 210, 225, 240,
        255, 270, 285, 300, 315, 330, 345};

    // Create a PolarChart object of size 460 x 460 pixels
    PolarChart *c = new PolarChart(460, 460);

    // Add a title to the chart at the top left corner using 15pt Arial Bold Italic font
    c->addTitle(Chart::TopLeft, "<*underline=2*>EM Field Strength", "arialbi.ttf", 15);

    // Set center of plot area at (230, 240) with radius 180 pixels
    c->setPlotArea(230, 240, 180);

    // Set the grid style to circular grid
    c->setGridStyle(false);

    // Add a legend box at the top right corner of the chart using 9pt Arial Bold font
    c->addLegend(459, 0, true, "arialbd.ttf", 9)->setAlignment(Chart::TopRight);

    // Set angular axis as 0 - 360, with a spoke every 30 units
    c->angularAxis()->setLinearScale(0, 360, 30);

    // Add a red (0xff9999) spline area layer to the chart using (data0, angles0)
    c->addSplineAreaLayer(DoubleArray(data0, (int)(sizeof(data0) / sizeof(data0[0]))), 0xff9999,
        "Above 100MHz")->setAngles(DoubleArray(angles0, (int)(sizeof(angles0) / sizeof(angles0[0])))
        );

    // Add a blue (0xff) spline line layer to the chart using (data1, angle1)
    PolarSplineLineLayer *layer1 = c->addSplineLineLayer(DoubleArray(data1, (int)(sizeof(data1) /
        sizeof(data1[0]))), 0x0000ff, "Below 100MHz");
    layer1->setAngles(DoubleArray(angles1, (int)(sizeof(angles1) / sizeof(angles1[0]))));

    // Set the line width to 3 pixels
    layer1->setLineWidth(3);

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

    //free up resources
    delete c;
    return 0;
}