Appendix B: Writing a Chart as a Bitmap Image
An IMSL C# Numerical Libraries chart can be saved as an image file using the .NET Image class.
The chart tree is constructed in the usual manner. Here a
method called
CreateChart
is used to create a simple chart, with the null-argument
Chart
constructor. The chart is written to a file without being displayed using the Chart.WritePNG
method. This method does not require a desktop GUI application using Windows.Forms,
but can be run in a “headless” mode.
If a chart is being displayed, a Bitmap object can be created using the Chart.PaintImage method. This object can then be used like any other .NET Image, including calling its Save method as in this example. For the Image returned by PaintImage not to be null, the chart must have been rendered to the screen. Therefore, this method is not suitable for headless applications.
using System;
using System.Drawing;
using System.IO;
using Imsl.Chart2D;
public class SampleImageIO : FrameChart
{
public SampleImageIO()
{
this.Chart = CreateChart();
// Create an image file from the chart's image once displayed
Bitmap bmap = new Bitmap(this.Chart.PaintImage());
bmap.Save("SampleImageIO2.png",
System.Drawing.Imaging.ImageFormat.Png);
}
static Chart CreateChart() {
Chart chart = new Chart();
AxisXY axis = new AxisXY(chart);
int npoints = 20;
double dx = .5 * Math.PI/(npoints-1);
double[] x = new double[npoints];
double[] y = new double[npoints];
// Generate some data
for (int i = 0; i < x.Length; i++)
{
x[i] = i * dx;
y[i] = Math.Sin(x[i]);
}
new Data(axis, x, y);
return chart;
}
public static void Main(string[] argv)
{
// Create an image file using WritePNG without a display
Chart chart = CreateChart();
chart.ScreenSize = new Size(500, 500);
FileStream fs =
new FileStream("SampleImageIO.png", FileMode.OpenOrCreate);
chart.WritePNG(fs, 500, 500);
System.Windows.Forms.Application.Run(new SampleImageIO());
}
}
|
PHONE: 713.784.3131 FAX:713.781.9260 |
