This example illustrates some of the background effects supported by ChartDirector.
ChartDirector supports the use of an image file as the wallpaper of the entire chart background and/or as the background of the plot area only. The former is by using
BaseChart.setWallpaper. The latter is by using the
PlotArea.setBackground2.
In addition to wallpapers, ChartDirector also supports different kinds of background colors. The plot area background can be alternately colored using
PlotArea.setBackground. You can also switch to a dark background with white lines and text in one step by changing the color palette to a
whiteOnBlackPalette using
BaseChart.setColors.
[The following project is available in "cppdemo/background".]
#include "chartdir.h"
void createChart(int img, const char *filename)
{
//The data for the chart
double data[] = {85, 156, 179.5, 211, 123};
const char *labels[] = {"Mon", "Tue", "Wed", "Thu", "Fri"};
//Create a XYChart object of size 270 x 270 pixels
XYChart *c = new XYChart(270, 270);
//Set the plot area at (40, 32) and of size 200 x 200 pixels
PlotArea *plotarea = c->setPlotArea(40, 32, 200, 200);
//Set the background style based on the input parameter
if (img == 0) {
//Has wallpaper image
c->setWallpaper("tile.gif");
} else if (img == 1) {
//Use a background image as the plot area background
plotarea->setBackground("bg.png");
} else if (img == 2) {
//Use white (0xffffff) and grey (0xe0e0e0) as two alternate plotarea
//background colors
plotarea->setBackground(0xffffff, 0xe0e0e0);
} else {
//Use a dark background palette
c->setColors(whiteOnBlackPalette);
}
//Set the labels on the x axis
c->xAxis()->setLabels(StringArray(labels, sizeof(labels)/sizeof(*labels)));
//Add a color bar layer using the given data. Use a 1 pixel 3D border for
//the bars.
c->addBarLayer(DoubleArray(data, sizeof(data)/sizeof(*data)), IntArray(0, 0)
)->setBorderColor(-1, 1);
//output the chart
c->makeChart(filename);
//free up resources
delete c;
}
int main(int argc, char *argv[]) {
createChart(0, "background0.png");
createChart(1, "background1.png");
createChart(2, "background2.png");
createChart(3, "background3.png");
return 0;
}
|
© 2003 Advanced Software Engineering Limited. All rights reserved.