ChartDirector 6.0 (C++ Edition)

Log Scale Axis


  

This example demonstrates using a log scale axis versus a linear scale axis.

In ChartDirector, log scale axis can be configured using Axis.setLogScale, Axis.setLogScale2 or Axis.setLogScale3.

Source Code Listing

[The following code is available in "cppdemo/logaxis". 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"

void createChart(int chartIndex, const char *filename)
{
    // The data for the chart
    double data[] = {100, 125, 260, 147, 67};
    const char *labels[] = {"Mon", "Tue", "Wed", "Thu", "Fri"};

    // Create a XYChart object of size 200 x 180 pixels
    XYChart *c = new XYChart(200, 180);

    // Set the plot area at (30, 10) and of size 140 x 130 pixels
    c->setPlotArea(30, 10, 140, 130);

    // Ise log scale axis if required
    if (chartIndex == 1) {
        c->yAxis()->setLogScale();
    }

    // Set the labels on the x axis
    c->xAxis()->setLabels(StringArray(labels, (int)(sizeof(labels) / sizeof(labels[0]))));

    // Add a color bar layer using the given data. Use a 1 pixel 3D border for the bars.
    c->addBarLayer(DoubleArray(data, (int)(sizeof(data) / sizeof(data[0]))), IntArray(0, 0)
        )->setBorderColor(-1, 1);

    // Output the chart
    c->makeChart(filename);

    //free up resources
    delete c;
}

int main(int argc, char *argv[])
{
    createChart(0, "logaxis0.png");
    createChart(1, "logaxis1.png");
    return 0;
}