ChartDirector Ver 3.0 (C++ Edition)

Polar Spline Chart




This example illustrates polar spline line and polar spline area. The polar spline line is added using PolarChart.addSplineLineLayer. The polar spline area is added using PolarChart.addSplineAreaLayer.

Source Code Listing

[The following project is available in "cppdemo/polarspline".]
#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 15pts Arial Bold //Italic font c->addTitle(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 9 pts Arial //Bold font c->addLegend(459, 0, true, "arialbd.ttf", 9)->setAlignment(TopRight); //Set angular axis as 0 - 360, either 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, sizeof(data0)/sizeof(*data0)), 0xff9999, "Above 100MHz")->setAngles(DoubleArray(angles0, sizeof(angles0)/sizeof(*angles0))); //Add a blue (0xff) spline line layer to the chart using (data1, angle1) PolarSplineLineLayer *layer1 = c->addSplineLineLayer(DoubleArray(data1, sizeof(data1)/sizeof(*data1)), 0xff, "Below 100MHz"); layer1->setAngles(DoubleArray(angles1, sizeof(angles1)/sizeof(*angles1))); //Set the line width to 3 pixels layer1->setLineWidth(3); //output the chart c->makeChart("polarspline.png"); //free up resources delete c; return 0; }