ChartDirector Ver 3.0 (C++ Edition)

Circular Label Layout


  

This example demonstrates how to control the positions of sector labels in circular label layout, and to enable join lines to connect the labels to the sectors. PieChart.setLabelPos is used to achieve these effects. This example also demonstrates how to specify the format of the label using PieChart.setLabelFormat.

Source Code Listing

[The following project is available in "cppdemo/circlelabelpie".]
#include "chartdir.h" void createChart(int img, const char *filename) { //The data for the pie chart double data[] = {25, 18, 15, 12, 30, 35}; //The labels for the pie chart const char *labels[] = {"Labor", "Licenses", "Taxes", "Legal", "Facilities", "Production"}; //Create a PieChart object of size 300 x 300 pixels PieChart *c = new PieChart(300, 300); if (img == 0) { //============================================================ // Draw a pie chart where the label is on top of the pie //============================================================ //Set the center of the pie at (150, 150) and the radius to 120 pixels c->setPieSize(150, 150, 120); //Set the label position to -40 pixels from the perimeter of the pie //(-ve means label is inside the pie) c->setLabelPos(-40); } else { //============================================================ // Draw a pie chart where the label is outside the pie //============================================================ //Set the center of the pie at (150, 150) and the radius to 80 pixels c->setPieSize(150, 150, 80); //Set the sector label position to be 20 pixels from the pie. Use a join //line to connect the labels to the sectors. c->setLabelPos(20, LineColor); } //Set the label format to three lines, showing the sector name, value, and //percentage. The value 999 will be formatted as US$999K. c->setLabelFormat("{label}\nUS${value}K\n({percent}%)"); //Set the pie data and the pie labels c->setData(DoubleArray(data, sizeof(data)/sizeof(*data)), StringArray( labels, sizeof(labels)/sizeof(*labels))); //Explode the 1st sector (index = 0) c->setExplode(0); //output the chart c->makeChart(filename); //free up resources delete c; } int main(int argc, char *argv[]) { createChart(0, "circlelabelpie0.png"); createChart(1, "circlelabelpie1.png"); return 0; }