ChartDirector Ver 3.0 (C++ Edition)

Dual Y-Axis




This example show demonstrates the dual independent y-axis feature of ChartDirector.

In ChartDirector, any data set can be binded to the primary y-axis or the secondary y-axis, controlled by DataSet.setUseYAxis2. The default is the primary y-axis.

The y-axes in this example are of different colors. This is achieved using Axis.setColors.

Source Code Listing

[The following project is available in "cppdemo/dualyaxis".]
#include "chartdir.h" int main(int argc, char *argv[]) { //The data for the chart double data0[] = {0.05, 0.06, 0.48, 0.1, 0.01, 0.05}; double data1[] = {100, 125, 265, 147, 67, 105}; const char *labels[] = {"Jan", "Feb", "Mar", "Apr", "May", "Jun"}; //Create a XYChart object of size 300 x 180 pixels XYChart *c = new XYChart(300, 180); //Set the plot area at (50, 20) and of size 200 x 130 pixels c->setPlotArea(50, 20, 200, 130); //Add a title to the chart using 8 pts Arial Bold font c->addTitle("Independent Y-Axis Demo", "arialbd.ttf", 8); //Set the x axis labels using the given labels c->xAxis()->setLabels(StringArray(labels, sizeof(labels)/sizeof(*labels))); //Add a title to the primary (left) y axis c->yAxis()->setTitle("Packet Drop Rate (pps)"); //Set the axis, label and title colors for the primary y axis to red //(0xc00000) to match the first data set c->yAxis()->setColors(0xc00000, 0xc00000, 0xc00000); //Add a title to the secondary (right) y axis c->yAxis2()->setTitle("Throughtput (MBytes)"); //set the axis, label and title colors for the primary y axis to green //(0x008000) to match the second data set c->yAxis2()->setColors(0x8000, 0x8000, 0x8000); //Add a line layer to for the first data set using red (0xc00000) color with //a line width to 3 pixels c->addLineLayer(DoubleArray(data0, sizeof(data0)/sizeof(*data0)), 0xc00000 )->setLineWidth(3); //Add a bar layer to for the second data set using green (0x00C000) color. //Bind the second data set to the secondary (right) y axis c->addBarLayer()->addDataSet(DoubleArray(data1, sizeof(data1)/sizeof(*data1) ), 0xc000)->setUseYAxis2(); //output the chart c->makeChart("dualyaxis.png"); //free up resources delete c; return 0; }