ChartDirector 6.0 (C++ Edition)

Multiple Axes




This example demonstrates using 4 y-axes in a chart.

The 4 axes are the default primary and secondary y-axes at the left and right edges of the plot area, and two other y-axes added using XYChart.addAxis.

Layer.setUseYAxis and Layer.setUseYAxis2 are used to bind the line layers to the axes. Axis.setTitle and TextBox.setAlignment are used to set the axis titles and put them on the top of the axes. Axis.setColors is used to set the axis colors to be the same as the corresponding line layers for easy matching.

Source Code Listing

[The following code is available in "cppdemo/multiaxes". 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[])
{
    // Data for the chart
    double data0[] = {1700, 3900, 2900, 3800, 4100, 4600, 2900, 4100, 4400, 5700, 5900, 5200, 3700,
        3400, 5100, 5600, 5600, 6000, 7000, 7600, 6300, 6700, 7500, 6400, 8800};
    double data1[] = {500, 550, 670, 990, 820, 730, 800, 720, 730, 790, 860, 800, 840, 680, 740,
        890, 680, 790, 730, 770, 840, 820, 800, 840, 670};
    double data2[] = {46, 68, 35, 33, 38, 20, 12, 18, 15, 23, 30, 24, 28, 15, 21, 26, 46, 42, 38,
        25, 23, 32, 24, 20, 25};
    double data3[] = {0.84, 0.82, 0.82, 0.38, 0.25, 0.52, 0.54, 0.52, 0.38, 0.51, 0.46, 0.29, 0.5,
        0.55, 0.47, 0.34, 0.52, 0.33, 0.21, 0.3, 0.25, 0.15, 0.18, 0.22, 0.14};

    // Labels for the chart
    const char *labels[] = {"0", "1", "2", "3", "4", "5", "6", "7", "8", "9", "10", "11", "12",
        "13", "14", "15", "16", "17", "18", "19", "20", "21", "22", "23", "24"};

    // Create a XYChart object of size 600 x 360 pixels. Use a vertical gradient color from sky blue
    // (aaccff) to white (ffffff) as background. Set border to grey (888888). Use rounded corners.
    // Enable soft drop shadow.
    XYChart *c = new XYChart(600, 360);
    c->setBackground(c->linearGradientColor(0, 0, 0, c->getHeight(), 0xaaccff, 0xffffff), 0x888888);
    c->setRoundedFrame();
    c->setDropShadow();

    // Add a title box to the chart using 15pt Arial Bold Italic font. Set top margin to 16 pixels.
    TextBox *title = c->addTitle("Multiple Axes Demonstration", "arialbi.ttf", 15);
    title->setMargin(0, 0, 16, 0);

    // Set the plotarea at (100, 80) and of size 400 x 230 pixels, with white (ffffff) background.
    // Use grey #(aaaaa) dotted lines for both horizontal and vertical grid lines.
    c->setPlotArea(100, 80, 400, 230, 0xffffff, -1, -1, c->dashLineColor(0xaaaaaa, Chart::DotLine),
        -1);

    // Add a legend box with the bottom center anchored at (300, 80) (top center of the plot area).
    // Use horizontal layout, and 8 points Arial Bold font. Set background and border to
    // transparent.
    LegendBox *legendBox = c->addLegend(300, 80, false, "arialbd.ttf", 8);
    legendBox->setAlignment(Chart::BottomCenter);
    legendBox->setBackground(Chart::Transparent, Chart::Transparent);

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

    // Display 1 out of 3 labels on the x-axis.
    c->xAxis()->setLabelStep(3);

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

    // Add a title on top of the primary (left) y axis.
    c->yAxis()->setTitle("Power\n(Watt)")->setAlignment(Chart::TopLeft2);
    // Set the axis, label and title colors for the primary y axis to red (c00000) to match the
    // first data set
    c->yAxis()->setColors(0xcc0000, 0xcc0000, 0xcc0000);

    // Add a title on top of the secondary (right) y axis.
    c->yAxis2()->setTitle("Load\n(Mbps)")->setAlignment(Chart::TopRight2);
    // Set the axis, label and title colors for the secondary y axis to green (00800000) to match
    // the second data set
    c->yAxis2()->setColors(0x008000, 0x008000, 0x008000);

    // Add the third y-axis at 50 pixels to the left of the plot area
    Axis *leftAxis = c->addAxis(Chart::Left, 50);
    // Add a title on top of the third y axis.
    leftAxis->setTitle("Temp\n(C)")->setAlignment(Chart::TopLeft2);
    // Set the axis, label and title colors for the third y axis to blue (0000cc) to match the third
    // data set
    leftAxis->setColors(0x0000cc, 0x0000cc, 0x0000cc);

    // Add the fouth y-axis at 50 pixels to the right of the plot area
    Axis *rightAxis = c->addAxis(Chart::Right, 50);
    // Add a title on top of the fourth y axis.
    rightAxis->setTitle("Error\n(%)")->setAlignment(Chart::TopRight2);
    // Set the axis, label and title colors for the fourth y axis to purple (880088) to match the
    // fourth data set
    rightAxis->setColors(0x880088, 0x880088, 0x880088);

    // Add a line layer to for the first data set using red (c00000) color, with a line width of 2
    // pixels
    LineLayer *layer0 = c->addLineLayer(DoubleArray(data0, (int)(sizeof(data0) / sizeof(data0[0]))),
        0xcc0000, "Power");
    layer0->setLineWidth(2);

    // Add a line layer to for the second data set using green (00c0000) color, with a line width of
    // 2 pixels. Bind the layer to the secondary y-axis.
    LineLayer *layer1 = c->addLineLayer(DoubleArray(data1, (int)(sizeof(data1) / sizeof(data1[0]))),
        0x008000, "Load");
    layer1->setLineWidth(2);
    layer1->setUseYAxis2();

    // Add a line layer to for the third data set using blue (0000cc) color, with a line width of 2
    // pixels. Bind the layer to the third y-axis.
    LineLayer *layer2 = c->addLineLayer(DoubleArray(data2, (int)(sizeof(data2) / sizeof(data2[0]))),
        0x0000cc, "Temperature");
    layer2->setLineWidth(2);
    layer2->setUseYAxis(leftAxis);

    // Add a line layer to for the fourth data set using purple (880088) color, with a line width of
    // 2 pixels. Bind the layer to the fourth y-axis.
    LineLayer *layer3 = c->addLineLayer(DoubleArray(data3, (int)(sizeof(data3) / sizeof(data3[0]))),
        0x880088, "Error Rate");
    layer3->setLineWidth(2);
    layer3->setUseYAxis(rightAxis);

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

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