ChartDirector 6.0 (C++ Edition)

Contour Chart

This example demonstrates creating a contour chart.

• The contour chart is created by adding a ContourLayer to the chart using XYChart.addContourLayer.

• By default, grid lines are drawn at the background of the plot area and so are behind all chart layers. In this example, PlotArea.moveGridBefore is used to move the grid lines in front of the contour layer.

• The color axis (visually represented as the color legend) is positioned vertically to the right of the plot area using ContourLayer.setColorAxis.

Source Code Listing

[The following code is available in "cppdemo/contour". 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" #include int main(int argc, char *argv[]) { // The x and y coordinates of the grid double dataX[] = {-10, -9, -8, -7, -6, -5, -4, -3, -2, -1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10}; double dataY[] = {-10, -9, -8, -7, -6, -5, -4, -3, -2, -1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10}; // The values at the grid points. In this example, we will compute the values using the formula // z = x * sin(y) + y * sin(x). double dataZ[(int)(sizeof(dataX) / sizeof(dataX[0])) * (int)(sizeof(dataY) / sizeof(dataY[0]))]; for(int yIndex = 0; yIndex < (int)(sizeof(dataY) / sizeof(dataY[0])); ++yIndex) { double y = dataY[yIndex]; for(int xIndex = 0; xIndex < (int)(sizeof(dataX) / sizeof(dataX[0])); ++xIndex) { double x = dataX[xIndex]; dataZ[yIndex * (int)(sizeof(dataX) / sizeof(dataX[0])) + xIndex] = x * sin(y) + y * sin( x); } } // Create a XYChart object of size 600 x 500 pixels XYChart *c = new XYChart(600, 500); // Add a title to the chart using 15 points Arial Bold Italic font c->addTitle("z = x * sin(y) + y * sin(x) ", "arialbi.ttf", 15); // Set the plotarea at (75, 40) and of size 400 x 400 pixels. Use semi-transparent black // (80000000) dotted lines for both horizontal and vertical grid lines c->setPlotArea(75, 40, 400, 400, -1, -1, -1, c->dashLineColor(0x80000000, Chart::DotLine), -1); // Set x-axis and y-axis title using 12 points Arial Bold Italic font c->xAxis()->setTitle("X-Axis Title Place Holder", "arialbi.ttf", 12); c->yAxis()->setTitle("Y-Axis Title Place Holder", "arialbi.ttf", 12); // Set x-axis and y-axis labels to use Arial Bold font c->xAxis()->setLabelStyle("arialbd.ttf"); c->yAxis()->setLabelStyle("arialbd.ttf"); // When auto-scaling, use tick spacing of 40 pixels as a guideline c->yAxis()->setTickDensity(40); c->xAxis()->setTickDensity(40); // Add a contour layer using the given data ContourLayer *layer = c->addContourLayer(DoubleArray(dataX, (int)(sizeof(dataX) / sizeof(dataX[0 ]))), DoubleArray(dataY, (int)(sizeof(dataY) / sizeof(dataY[0]))), DoubleArray(dataZ, (int)( sizeof(dataZ) / sizeof(dataZ[0])))); // Move the grid lines in front of the contour layer c->getPlotArea()->moveGridBefore(layer); // Add a color axis (the legend) in which the top left corner is anchored at (505, 40). Set the // length to 400 pixels and the labels on the right side. ColorAxis *cAxis = layer->setColorAxis(505, 40, Chart::TopLeft, 400, Chart::Right); // Add a title to the color axis using 12 points Arial Bold Italic font cAxis->setTitle("Color Legend Title Place Holder", "arialbi.ttf", 12); // Set color axis labels to use Arial Bold font cAxis->setLabelStyle("arialbd.ttf"); // Output the chart c->makeChart("contour.png"); //free up resources delete c; return 0; }```