ChartDirector 6.0 (C++ Edition)

Overlapping Bar Chart




This example demonstrates a multi-bar chart in which the bars within a cluster overlaps.

The overlapping effect is configured using BarLayer.setOverlapRatio. This method allows you to specify overlapping ratio and order. In this example, the overlapping ratio is 0.5, while the default overlapping order is used. The default order is that the first data set will stay on top of the second data set, and so on.

Source Code Listing

[The following code is available in "cppdemo/overlapbar". 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 bar chart
    double data0[] = {100, 125, 156, 147, 87, 124, 178, 109, 140, 106, 192, 122};
    double data1[] = {122, 156, 179, 211, 198, 177, 160, 220, 190, 188, 220, 270};
    double data2[] = {167, 190, 213, 267, 250, 320, 212, 199, 245, 267, 240, 310};
    const char *labels[] = {"Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug", "Sept", "Oct",
        "Nov", "Dec"};

    // Create a XYChart object of size 580 x 280 pixels
    XYChart *c = new XYChart(580, 280);

    // Add a title to the chart using 14pt Arial Bold Italic font
    c->addTitle("Product Revenue For Last 3 Years", "arialbi.ttf", 14);

    // Set the plot area at (50, 50) and of size 500 x 200. Use two alternative background colors
    // (f8f8f8 and ffffff)
    c->setPlotArea(50, 50, 500, 200, 0xf8f8f8, 0xffffff);

    // Add a legend box at (50, 25) using horizontal layout. Use 8pt Arial as font, with transparent
    // background.
    c->addLegend(50, 25, false, "arial.ttf", 8)->setBackground(Chart::Transparent);

    // Set the x axis labels
    c->xAxis()->setLabels(StringArray(labels, (int)(sizeof(labels) / sizeof(labels[0]))));

    // Draw the ticks between label positions (instead of at label positions)
    c->xAxis()->setTickOffset(0.5);

    // Add a multi-bar layer with 3 data sets
    BarLayer *layer = c->addBarLayer(Chart::Side);
    layer->addDataSet(DoubleArray(data0, (int)(sizeof(data0) / sizeof(data0[0]))), 0xff8080,
        "Year 2003");
    layer->addDataSet(DoubleArray(data1, (int)(sizeof(data1) / sizeof(data1[0]))), 0x80ff80,
        "Year 2004");
    layer->addDataSet(DoubleArray(data2, (int)(sizeof(data2) / sizeof(data2[0]))), 0x8080ff,
        "Year 2005");

    // Set 50% overlap between bars
    layer->setOverlapRatio(0.5);

    // Add a title to the y-axis
    c->yAxis()->setTitle("Revenue (USD in millions)");

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

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