Polygon Bar Shapes

This example demonstrates bars of various polygonal shapes.

ChartDirector supports bars in cylindrical or arbitrary polygonal shapes. This is specified by using BarLayer.setBarShape and BarLayer.setBarShape2. In this example, various polygonal shapes are illustrated.

See Shape Specification on how built-in and custom shapes are defined in ChartDirector.

For demonstration, in this example each bar is of a different shape. BarLayer.setBarShape and BarLayer.setBarShape2 also supports setting the bar shapes based on data groups (or data sets) or data item position. For an example, see Multi-Shape Bar Chart.

The following is the command line version of the code in "cppdemo/polygonbar". The MFC version of the code is in "mfcdemo/mfcdemo". The Qt Widgets version of the code is in "qtdemo/qtdemo". The QML/Qt Quick version of the code is in "qmldemo/qmldemo".

#include "chartdir.h"

int main(int argc, char *argv[])
{
    // The data for the bar chart
    double data[] = {85, 156, 179.5, 211, 123, 176, 195};
    const int data_size = (int)(sizeof(data)/sizeof(*data));

    // The labels for the bar chart
    const char* labels[] = {"Square", "Star(8)", "Polygon(6)", "Cross", "Cross2", "Diamond",
        "Custom"};
    const int labels_size = (int)(sizeof(labels)/sizeof(*labels));

    // Create a XYChart object of size 500 x 280 pixels.
    XYChart* c = new XYChart(500, 280);

    // Set the plotarea at (50, 40) with alternating light grey (f8f8f8) / white (ffffff) background
    c->setPlotArea(50, 40, 400, 200, 0xf8f8f8, 0xffffff);

    // Add a title to the chart using 14pt Arial Bold Italic font
    c->addTitle("    Bar Shape Demonstration", "Arial Bold Italic", 14);

    // Add a multi-color bar chart layer
    BarLayer* layer = c->addBarLayer(DoubleArray(data, data_size), IntArray(0, 0));

    // Set layer to 3D with 10 pixels 3D depth
    layer->set3D(10);

    // Set bar shape to circular (cylinder)
    layer->setBarShape(Chart::CircleShape);

    // Set the first bar (index = 0) to square shape
    layer->setBarShape(Chart::SquareShape, 0, 0);

    // Set the second bar to 8-pointed star
    layer->setBarShape(Chart::StarShape(8), 0, 1);

    // Set the third bar to 6-sided polygon
    layer->setBarShape(Chart::PolygonShape(6), 0, 2);

    // Set the next 3 bars to cross shape, X shape and diamond shape
    layer->setBarShape(Chart::CrossShape(), 0, 3);
    layer->setBarShape(Chart::Cross2Shape(), 0, 4);
    layer->setBarShape(Chart::DiamondShape, 0, 5);

    // Set the last bar to a custom shape, specified as an array of (x, y) points in normalized
    // coordinates
    int customShape[] = {-500, 0, 0, 500, 500, 0, 500, 1000, 0, 500, -500, 1000};
    const int customShape_size = (int)(sizeof(customShape)/sizeof(*customShape));
    layer->setBarShape(IntArray(customShape, customShape_size), 0, 6);

    // Set the labels on the x axis.
    c->xAxis()->setLabels(StringArray(labels, labels_size));

    // Add a title to the y axis
    c->yAxis()->setTitle("Frequency");

    // Add a title to the x axis
    c->xAxis()->setTitle("Shapes");

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

    //free up resources
    delete c;

    return 0;
}