ChartDirector 6.0 (C++ Edition)

Circular Zones




This example demonstrates adding circular zones to a polar chart.

In ChartDirector, a zone defined on the radial axis will mark a radius range, and so will appear as ring on a polar chart.

This example contains three circular zones in the plot area background, colored as red, green and blue. The blue region is the original background of the plot area, while the red and green regions are added using Axis.addZone of the radial axis object.

Source Code Listing

[The following code is available in "cppdemo/polarzones". 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[] = {51, 15, 51, 40, 17, 87, 94, 21, 35, 88, 50, 60};

    // 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
    PolarChart *c = new PolarChart(400, 420);

    // Set background color to a 2 pixel pattern color, with a black border and 1 pixel 3D border
    // effect
    int pattern1[] = {0xffffff, 0xe0e0e0};
    c->setBackground(c->patternColor(IntArray(pattern1, (int)(sizeof(pattern1) / sizeof(pattern1[0])
        )), 2), 0, 1);

    // Add a title to the chart using 16pt Arial Bold Italic font. The title text is white
    // (0xffffff) on 2 pixel pattern background
    int pattern2[] = {0x000000, 0x000080};
    c->addTitle("Chemical Concentration", "arialbi.ttf", 16, 0xffffff)->setBackground(
        c->patternColor(IntArray(pattern2, (int)(sizeof(pattern2) / sizeof(pattern2[0]))), 2));

    // Set center of plot area at (200, 240) with radius 145 pixels. Set background color to blue
    // (9999ff)
    c->setPlotArea(200, 240, 145, 0x9999ff);

    // Color the region between radius = 40 to 80 as green (99ff99)
    c->radialAxis()->addZone(40, 80, 0x99ff99);

    // Color the region with radius > 80 as red (ff9999)
    c->radialAxis()->addZone(80, 999, 0xff9999);

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

    // Set the radial axis label format
    c->radialAxis()->setLabelFormat("{value} ppm");

    // 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/green/blue zones
    legendBox->addKey("Under-Absorp", 0x9999ff);
    legendBox->addKey("Normal", 0x99ff99);
    legendBox->addKey("Over-Absorp", 0xff9999);

    // Add a blue (000080) spline line layer with line width set to 3 pixels and using yellow
    // (ffff00) circles to represent the data points
    PolarSplineLineLayer *layer = c->addSplineLineLayer(DoubleArray(data, (int)(sizeof(data) /
        sizeof(data[0]))), 0x000080);
    layer->setLineWidth(3);
    layer->setDataSymbol(Chart::CircleShape, 11, 0xffff00);

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

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

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