ChartDirector Ver 3.0 (C++ Edition)

Rotated Line Chart




This example demonstrates swapping the x and y axes to produce a rotated line chart in which the line goes from top to bottom (instead of left to right).

The x and y axes in the example are configured as follows:

For demo purposes, this example uses RanTable to simulate a database table with 4 columns, in which one is a date/time column and the remaining three are data columns. The date/time column is passed to ChartDirector as the x values using Layer.setXData, while the data columns are passed to ChartDirector as y values using Layer.addDataSet.

Source Code Listing

[The following project is available in "cppdemo/rotatedline".]
#include "chartdir.h" int main(int argc, char *argv[]) { // // We use a random table to simulate generating 12 months of data // //Create the random table object with 4 cols * 12 rows, using 3 as seed RanTable *rantable = new RanTable(3, 4, 12); //Set the 1st column to be the 12 months of year 2002 rantable->setDateCol(0, chartTime(2002, 1, 1), 86400 * 30); //Set the 2nd, 3rd and 4th columns to be random numbers starting from 125, //75, and 100 respectively. The change between rows is set to -35 to + 35. //The minimum value of any cell is 0. rantable->setCol(1, 125, -35, 35, 0); rantable->setCol(2, 75, -35, 35, 0); rantable->setCol(3, 100, -35, 35, 0); //Get the 1st column (time) as the x data DoubleArray dataX = rantable->getCol(0); //Get the 2nd, 3rd and 4th columns as 3 data sets DoubleArray dataY0 = rantable->getCol(1); DoubleArray dataY1 = rantable->getCol(2); DoubleArray dataY2 = rantable->getCol(3); //Create a XYChart object of size 360 x 400 pixels XYChart *c = new XYChart(360, 400); //Add a title to the chart c->addTitle("<*underline=2*>Rotated Line Chart Demo", "timesbi.ttf", 14); //Set the plotarea at (60, 75) and of size 190 x 320 pixels. Turn on both //horizontal and vertical grid lines with light grey color (0xc0c0c0) c->setPlotArea(60, 75, 190, 320)->setGridColor(0xc0c0c0, 0xc0c0c0); //Add a legend box at (270, 75) c->addLegend(270, 75); //Swap the x and y axis to become a rotated chart c->swapXY(); //Set the y axis on the top side (right + rotated = top) c->setYAxisOnRight(); //Add a title to the y axis c->yAxis()->setTitle("Throughput (MBytes)"); //Reverse the x axis so it is pointing downwards c->xAxis()->setReverse(); //Add a line chart layer using the given data LineLayer *layer = c->addLineLayer(); layer->setXData(dataX); layer->addDataSet(dataY0, 0xff0000, "Server A"); layer->addDataSet(dataY1, 0x338033, "Server B"); layer->addDataSet(dataY2, 0xff, "Server C"); //Set the line width to 2 pixels layer->setLineWidth(2); //output the chart c->makeChart("rotatedline.png"); //free up resources delete rantable; delete c; return 0; }