ChartDirector 6.0 (C++ Edition)

Gradient Bar Shading




This example demonstrates using bar gradient shading for a horizontal bar chart. It also demonstrates using gradient color background, partially rounded frame, and automatic resizing of the plot area to fit the chart.

Source Code Listing

[The following code is available in "cppdemo/gradientbar". 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 data for the bar chart
    double data[] = {1350, 1600, 1950, 2300, 2700};

    // The labels for the bar chart
    const char *labels[] = {"2001", "2002", "2003", "2004", "2005"};

    // The colors for the bars
    int colors[] = {0xcc0000, 0x66aaee, 0xeebb22, 0xcccccc, 0xcc88ff};

    // Create a PieChart object of size 600 x 380 pixels.
    XYChart *c = new XYChart(600, 380);

    // Use the white on black palette, which means the default text and line colors are white
    c->setColors(Chart::whiteOnBlackPalette);

    // Use a vertical gradient color from blue (0000cc) to deep blue (000044) as background. Use
    // rounded corners of 30 pixels radius for the top-left and bottom-right corners.
    c->setBackground(c->linearGradientColor(0, 0, 0, c->getHeight(), 0x0000cc, 0x000044));
    c->setRoundedFrame(0xffffff, 30, 0, 30, 0);

    // Add a title using 18pt Times New Roman Bold Italic font. Add 6 pixels top and bottom margins
    // to the title.
    TextBox *title = c->addTitle("Annual Revenue for Star Tech", "timesbi.ttf", 18);
    title->setMargin(0, 0, 6, 6);

    // Add a separator line in white color just under the title
    c->addLine(20, title->getHeight(), c->getWidth() - 21, title->getHeight(), 0xffffff);

    // Tentatively set the plotarea at (70, 80) and of 480 x 240 pixels in size. Use transparent
    // border and white grid lines
    c->setPlotArea(70, 80, 480, 240, -1, -1, Chart::Transparent, 0xffffff);

    // Swap the axis so that the bars are drawn horizontally
    c->swapXY();

    // Add a multi-color bar chart layer using the supplied data. Use bar gradient lighting with the
    // light intensity from 0.75 to 2.0
    c->addBarLayer(DoubleArray(data, (int)(sizeof(data) / sizeof(data[0]))), IntArray(colors, (int)(
        sizeof(colors) / sizeof(colors[0]))))->setBorderColor(Chart::Transparent,
        Chart::barLighting(0.75, 2.0));

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

    // Show the same scale on the left and right y-axes
    c->syncYAxis();

    // Set the bottom y-axis title using 10pt Arial Bold font
    c->yAxis()->setTitle("USD (millions)", "arialbd.ttf", 10);

    // Set y-axes to transparent
    c->yAxis()->setColors(Chart::Transparent);
    c->yAxis2()->setColors(Chart::Transparent);

    // Disable ticks on the x-axis by setting the tick color to transparent
    c->xAxis()->setTickColor(Chart::Transparent);

    // Set the label styles of all axes to 8pt Arial Bold font
    c->xAxis()->setLabelStyle("arialbd.ttf", 8);
    c->yAxis()->setLabelStyle("arialbd.ttf", 8);
    c->yAxis2()->setLabelStyle("arialbd.ttf", 8);

    // Adjust the plot area size, such that the bounding box (inclusive of axes) is 30 pixels from
    // the left edge, 25 pixels below the title, 50 pixels from the right edge, and 25 pixels from
    // the bottom edge.
    c->packPlotArea(30, title->getHeight() + 25, c->getWidth() - 50, c->getHeight() - 25);

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

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