ChartDirector Ver 4.1 (C++ Edition)

Vector Chart




This example demonstrates a vector chart.

A vector chart is like a scatter chart, but the symbols are arrows which can be of arbitrary lengths pointing to arbitrary directions. Thus each symbol in a vector chart is specified by 4 values - the x and y coordinates, the length and the direction.

In ChartDirector, an XY vector layer is created using XYChart.addVectorLayer.

Source Code Listing

[The following code is available in "cppdemo/vector". A MFC version of the code is available in "mfcdemo" (Windows edition only).]
#include "chartdir.h"

int main(int argc, char *argv[])
{
    // The (x, y) coordinates of the starting point of the vectors
    double dataX[] = {20, 40, 60, 80, 100, 20, 40, 60, 80, 100, 20, 40, 58, 62, 80,
        100, 20, 40, 60, 80, 100, 20, 40, 60, 80, 100};
    double dataY[] = {20, 20, 20, 20, 20, 40, 40, 40, 40, 40, 60, 60, 60, 60, 60, 60,
        80, 80, 80, 80, 80, 100, 100, 100, 100, 100};

    // The lengths (radii) and directions (angles) of the vectors
    double dataR[] = {6, 6, 9, 6, 6, 6, 9, 12, 9, 6, 9, 12, 12, 12, 12, 9, 6, 9, 12,
        9, 6, 6, 6, 9, 6, 6};
    double dataA[] = {-45, -30, 0, 30, 45, -60, -45, 0, 45, 60, -90, -90, -90, 90,
        90, 90, -120, -135, 180, 135, 120, -135, -150, 180, 150, 135};

    // Create a XYChart object of size 450 x 390 pixels
    XYChart *c = new XYChart(450, 390);

    // 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, -1, -1, 0xc0c0c0, 0xc0c0c0, -1);

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

    // Add a title to the y axis using 12 pts Arial Bold Italic font
    c->yAxis()->setTitle("Y Axis Title", "arialbi.ttf", 12);

    // Add a title to the x axis using 12 pts Arial Bold Italic font
    c->xAxis()->setTitle("X Axis Title", "arialbi.ttf", 12);

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

    // Add a vector layer to the chart using blue (0000CC) color, with vector arrow
    // size set to 11 pixels
    c->addVectorLayer(DoubleArray(dataX, sizeof(dataX)/sizeof(dataX[0])),
        DoubleArray(dataY, sizeof(dataY)/sizeof(dataY[0])), DoubleArray(dataR,
        sizeof(dataR)/sizeof(dataR[0])), DoubleArray(dataA,
        sizeof(dataA)/sizeof(dataA[0])), Chart::YAxisScale, 0x0000cc)->setArrowHead(
        11);

    // output the chart
    c->makeChart("vector.png");

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