ChartDirector 7.1 (C++ Edition)

Surface Color Scale


      

This example demonstrates using various color scales for surface charts.

ChartDirector supports two ways to configure the color scale:

This example includes 4 charts to demonstrate both of the above methods.

Source Code Listing

The following is the command line version of the code in "cppdemo/surfacecolor". 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" void createChart(int chartIndex, const char *filename) { // The x and y coordinates of the grid double dataX[] = {-4, -3, -2, -1, 0, 1, 2, 3, 4}; const int dataX_size = (int)(sizeof(dataX)/sizeof(*dataX)); double dataY[] = {-4, -3, -2, -1, 0, 1, 2, 3, 4}; const int dataY_size = (int)(sizeof(dataY)/sizeof(*dataY)); // Use random numbers for the z values on the XY grid RanSeries* r = new RanSeries(99); DoubleArray dataZ = r->get2DSeries(dataX_size, dataY_size, -0.9, 0.9); // Create a SurfaceChart object of size 460 x 460 pixels with white (0xffffff) background and // grey (0x888888) border SurfaceChart* c = new SurfaceChart(460, 460, 0xffffff, 0x888888); // Set the surface data c->setData(DoubleArray(dataX, dataX_size), DoubleArray(dataY, dataY_size), dataZ); // Add a color axis (the legend) in at the top center of the chart, with labels at the bottom. // Set the axis to flat style. ColorAxis* cAxis = c->setColorAxis(c->getWidth() / 2, 15, Chart::Top, 250, Chart::Bottom); cAxis->setTitle("Color Axis"); cAxis->setAxisBorder(Chart::Transparent, 0); // By default, the color axis is synchronized with the z-axis. The following code remove the // synchronization so that the color axis will auto-scale independently. Set the auto-scale // minimum tick spacing to 20 pixels. cAxis->syncAxis(0); cAxis->setTickDensity(20); if (chartIndex == 1) { // Speicify a color gradient as a list of colors, and use it in the color axis. int colorGradient[] = {0x0044cc, 0xffffff, 0x00aa00}; const int colorGradient_size = (int)(sizeof(colorGradient)/sizeof(*colorGradient)); cAxis->setColorGradient(false, IntArray(colorGradient, colorGradient_size)); } else if (chartIndex == 2) { // Specify the color scale to use in the color axis double colorScale[] = {-1.0, 0x1a9850, -0.75, 0x66bd63, -0.5, 0xa6d96a, -0.25, 0xd9ef8b, 0, 0xfee08b, 0.25, 0xfdae61, 0.5, 0xf46d43, 0.75, 0xd73027, 1}; const int colorScale_size = (int)(sizeof(colorScale)/sizeof(*colorScale)); cAxis->setColorScale(DoubleArray(colorScale, colorScale_size)); } else if (chartIndex == 3) { // Specify the color scale to use in the color axis. Also specify an underflow color // 0x66ccff (blue) for regions that fall below the lower axis limit. double colorScale[] = {0, 0xffff99, 0.2, 0x80cdc1, 0.4, 0x35978f, 0.6, 0x01665e, 0.8, 0x003c30, 1}; const int colorScale_size = (int)(sizeof(colorScale)/sizeof(*colorScale)); cAxis->setColorScale(DoubleArray(colorScale, colorScale_size), 0x66ccff); } // Set the center of the plot region at (230, 250), and set width x depth x height to 240 x 240 // x 170 pixels c->setPlotRegion(230, 250, 240, 240, 170); // Set the plot region wall thichness to 3 pixels c->setWallThickness(3); // Set the elevation and rotation angles to 45 degrees c->setViewAngle(45, 45); // Set the perspective level to 20 c->setPerspective(20); // Spline interpolate data to a 50 x 50 grid for a smooth surface c->setInterpolation(50, 50); // Set the axis title c->xAxis()->setTitle("X-Axis", "Arial Bold", 10); c->yAxis()->setTitle("Y-Axis", "Arial Bold", 10); c->zAxis()->setTitle("Z Axis", "Arial Bold", 10); // Output the chart c->makeChart(filename); //free up resources delete r; delete c; } int main(int argc, char *argv[]) { createChart(0, "surfacecolor0.png"); createChart(1, "surfacecolor1.png"); createChart(2, "surfacecolor2.png"); createChart(3, "surfacecolor3.png"); return 0; }