ChartDirector 6.0 (C++ Edition)

Custom Scatter Labels




This example demonstrates adding custom labels to data points.

Source Code Listing

[The following code is available in "cppdemo/scatterlabels". 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 XY points for the scatter chart
    double dataX[] = {150, 400, 300, 1500, 800};
    double dataY[] = {0.6, 8, 5.4, 2, 4};

    // The labels for the points
    const char *labels[] = {"Nano\n100", "SpeedTron\n200 Lite", "SpeedTron\n200", "Marathon\nExtra",
        "Marathon\n2000"};

    // Create a XYChart object of size 450 x 400 pixels
    XYChart *c = new XYChart(450, 400);

    // Set the plotarea at (55, 40) and of size 350 x 300 pixels, with a light grey border
    // (0xc0c0c0). Turn on both horizontal and vertical grid lines with light grey color (0xc0c0c0)
    c->setPlotArea(55, 40, 350, 300, 0xffffff, -1, 0xc0c0c0, 0xc0c0c0, -1);

    // Add a title to the chart using 18pt Times Bold Itatic font.
    c->addTitle("Product Comparison Chart", "timesbi.ttf", 18);

    // Add a title to the y axis using 12pt Arial Bold Italic font
    c->yAxis()->setTitle("Capacity (tons)", "arialbi.ttf", 12);

    // Add a title to the x axis using 12pt Arial Bold Italic font
    c->xAxis()->setTitle("Range (miles)", "arialbi.ttf", 12);

    // Set the axes line width to 3 pixels
    c->xAxis()->setWidth(3);
    c->yAxis()->setWidth(3);

    // Add the data as a scatter chart layer, using a 15 pixel circle as the symbol
    ScatterLayer *layer = c->addScatterLayer(DoubleArray(dataX, (int)(sizeof(dataX) / sizeof(dataX[0
        ]))), DoubleArray(dataY, (int)(sizeof(dataY) / sizeof(dataY[0]))), "",
        Chart::GlassSphereShape, 15, 0xff3333, 0xff3333);

    // Add labels to the chart as an extra field
    layer->addExtraField(StringArray(labels, (int)(sizeof(labels) / sizeof(labels[0]))));

    // Set the data label format to display the extra field
    layer->setDataLabelFormat("{field0}");

    // Use 8pt Arial Bold to display the labels
    TextBox *textbox = layer->setDataLabelStyle("arialbd.ttf", 8);

    // Set the background to purple with a 1 pixel 3D border
    textbox->setBackground(0xcc99ff, Chart::Transparent, 1);

    // Put the text box 4 pixels to the right of the data point
    textbox->setAlignment(Chart::Left);
    textbox->setPos(4, 0);

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

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