ChartDirector 6.0 (C++ Edition)

Sector Zones




This example demonstrates adding sector zones to a polar chart.

In ChartDirector, a zone defined on the angular axis will mark an angular range, and so will appear as sectors on a polar chart.

This example contains three sector zones in the plot area background, colored as red, yellow and green. The green region is the original background of the plot area, while the red and yellow regions are added using AngularAxis.addZone.

Source Code Listing

[The following code is available in "cppdemo/polarzones2". 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 chart
    double data[] = {5.1, 1.5, 5.1, 4.0, 1.7, 8.7, 9.4, 2.1, 3.5, 8.8, 5.0, 6.0};

    // The labels for the chart
    const char *labels[] = {"Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug", "Sept", "Oct",
        "Nov", "Dec"};

    // Create a PolarChart object of size 400 x 420 pixels. with a metallic blue (9999ff) background
    // color and 1 pixel 3D border
    PolarChart *c = new PolarChart(400, 420, Chart::metalColor(0x9999ff), 0x000000, 1);

    // Add a title to the chart using 16pt Arial Bold Italic font. The title text is white
    // (0xffffff) on deep blue (000080) background
    c->addTitle("Chemical Concentration", "arialbi.ttf", 16, 0xffffff)->setBackground(0x000080);

    // Set center of plot area at (200, 240) with radius 145 pixels. Set background color to green
    // (0x33ff33)
    c->setPlotArea(200, 240, 145, 0x33ff33);

    // Set the labels to the angular axis
    c->angularAxis()->setLabels(StringArray(labels, (int)(sizeof(labels) / sizeof(labels[0]))));

    // Color the sector between label index = 5.5 to 7.5 as red (ff3333) zone
    c->angularAxis()->addZone(5.5, 7.5, 0xff3333);

    // Color the sector between label index = 4.5 to 5.5, and also between 7.5 to 8.5, as yellow
    // (ff3333) zones
    c->angularAxis()->addZone(4.5, 5.5, 0xffff00);
    c->angularAxis()->addZone(7.5, 8.5, 0xffff00);

    // Set the grid style to circular grid
    c->setGridStyle(false);

    // Use semi-transparent (40ffffff) label background so as not to block the data
    c->radialAxis()->setLabelStyle()->setBackground(0x40ffffff, 0x40000000);

    // Add a legend box at (200, 30) top center aligned, using 9pt Arial Bold font. with a black
    // border.
    LegendBox *legendBox = c->addLegend(200, 30, false, "arialbd.ttf", 9);
    legendBox->setAlignment(Chart::TopCenter);

    // Add legend keys to represent the red/yellow/green zones
    legendBox->addKey("Very Dry", 0xff3333);
    legendBox->addKey("Critical", 0xffff00);
    legendBox->addKey("Moderate", 0x33ff33);

    // Add a blue (0x80) line layer with line width set to 3 pixels and use purple (ff00ff) cross
    // symbols for the data points
    PolarLineLayer *layer = c->addLineLayer(DoubleArray(data, (int)(sizeof(data) / sizeof(data[0]))
        ), 0x000080);
    layer->setLineWidth(3);
    layer->setDataSymbol(Chart::Cross2Shape(), 15, 0xff00ff);

    // Output the chart
    c->makeChart("polarzones2.png");

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