ChartDirector Ver 3.0 (C++ Edition)

Multi-Bar Chart




A multi-bar chart is a bar chart in which multiple data sets are represented by drawing the bars side by side in a cluster. The multi-bar layer is created by using XYChart.addBarLayer2 with the Side pre-defined constant.

This example employs two alternative colors as the plot area background. This is achieved by using PlotArea.setBackground.

In this example, a margin is configured at the top of the plot area for the legend keys. This is achieved by using Axis.setMargin.

Source Code Listing

[The following project is available in "cppdemo/multibar".]
#include "chartdir.h" int main(int argc, char *argv[]) { //The data for the bar chart double data0[] = {100, 125, 245, 147, 67}; double data1[] = {85, 156, 179, 211, 123}; double data2[] = {97, 87, 56, 267, 157}; const char *labels[] = {"Mon", "Tue", "Wed", "Thu", "Fri"}; //Create a XYChart object of size 300 x 240 pixels XYChart *c = new XYChart(300, 240); //Add a title to the chart using 10 pt Arial font c->addTitle(" Average Weekday Network Load", "", 10); //Set the plot area at (45, 25) and of size 239 x 180. Use two alternative //background colors (0xffffc0 and 0xffffe0) c->setPlotArea(45, 25, 239, 180)->setBackground(0xffffc0, 0xffffe0); //Add a legend box at (45, 20) using horizontal layout. Use 8 pt Arial font, //with transparent background c->addLegend(45, 20, false, "", 8)->setBackground(Transparent); //Add a title to the y-axis c->yAxis()->setTitle("Throughput (MBytes Per Hour)"); //Reserve 20 pixels at the top of the y-axis for the legend box c->yAxis()->setTopMargin(20); //Set the x axis labels c->xAxis()->setLabels(StringArray(labels, sizeof(labels)/sizeof(*labels))); //Add a multi-bar layer with 3 data sets Layer *layer = c->addBarLayer(Side, 3); layer->addDataSet(DoubleArray(data0, sizeof(data0)/sizeof(*data0)), 0xff8080, "Server #1"); layer->addDataSet(DoubleArray(data1, sizeof(data1)/sizeof(*data1)), 0x80ff80, "Server #2"); layer->addDataSet(DoubleArray(data2, sizeof(data2)/sizeof(*data2)), 0x8080ff, "Server #3"); //output the chart c->makeChart("multibar.png"); //free up resources delete c; return 0; }