Pattern Area Chart

This example demonstrates using a pattern for filling the area in an area chart, together with a number of chart formatting features.

Create an XYChart object with background color and border using XYChart.XYChart.
Set the background color of the title box using Box.setBackground. The background color is a pattern color created using BaseChart.patternColor.
Enable both vertical and horizontal grid lines using XYChart.setPlotArea. The grid colors are dash line colors created using BaseChart.dashLineColor.
Create a pattern color with a "snow pattern" loaded from an image file using BaseChart.patternColor2.
Use DataSet.setDataColor to specify the area fill and border colors. Use the "snow pattern" as the area fill color.
Use Layer.setLineWidth to increase the border width of the area to highlight it.

The following is the command line version of the code in "cppdemo/patternarea". The MFC version of the code is in "mfcdemo/mfcdemo". The Qt Widgets version of the code is in "qtdemo/qtdemo". The QML/Qt Quick version of the code is in "qmldemo/qmldemo".

#include "chartdir.h"

int main(int argc, char *argv[])
{
    // The data for the area chart
    double data[] = {3.0, 2.8, 4.0, 5.5, 7.5, 6.8, 5.4, 6.0, 5.0, 6.2, 7.5, 6.5, 7.5, 8.1, 6.0, 5.5,
        5.3, 3.5, 5.0, 6.6, 5.6, 4.8, 5.2, 6.5, 6.2};
    const int data_size = (int)(sizeof(data)/sizeof(*data));

    // The labels for the area 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"};
    const int labels_size = (int)(sizeof(labels)/sizeof(*labels));

    // Create a XYChart object of size 300 x 180 pixels. Set the background to pale yellow
    // (0xffffa0) with a black border (0x0)
    XYChart* c = new XYChart(300, 180, 0xffffa0, 0x000000);

    // Set the plotarea at (45, 35) and of size 240 x 120 pixels. Set the background to white
    // (0xffffff). Set both horizontal and vertical grid lines to black (&H0&) dotted lines (pattern
    // code 0x0103)
    c->setPlotArea(45, 35, 240, 120, 0xffffff, -1, -1, c->dashLineColor(0x000000, 0x000103),
        c->dashLineColor(0x000000, 0x000103));

    // Add a title to the chart using 10pt Arial Bold font. Use a 1 x 2 bitmap pattern as the
    // background. Set the border to black (0x0).
    int titleBg[] = {0xb0b0f0, 0xe0e0ff};
    c->addTitle("Snow Percipitation (Dec 12)", "Arial Bold", 10)->setBackground(c->patternColor(
        IntArray(titleBg, 2), 2), 0x000000);

    // Add a title to the y axis
    c->yAxis()->setTitle("mm per hour");

    // Set the labels on the x axis.
    c->xAxis()->setLabels(StringArray(labels, labels_size));

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

    // Add an area layer to the chart
    AreaLayer* layer = c->addAreaLayer();

    // Load a snow pattern from an external file "snow.png".
    int snowPattern = c->patternColor("snow.png");

    // Add a data set to the area layer using the snow pattern as the fill color. Use deep blue
    // (0x0000ff) as the area border line color (&H0000ff&)
    layer->addDataSet(DoubleArray(data, data_size))->setDataColor(snowPattern, 0x0000ff);

    // Set the line width to 2 pixels to highlight the line
    layer->setLineWidth(2);

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

    //free up resources
    delete c;

    return 0;
}