free grads

wi

N.B.: This command was deprecated long ago and is not included in grads version 1.9 or later.

The wi (write image) command dumps an exact copy of the contents of the grads graphics screen directly to an image file. This feature is implemented by means of an interface to the ImageMagick library. The syntax is:    

wi filename.fmt

where filename can be any meaningful file name, and fmt is one of the ImageMagick supported formats: gif, bmp, cgm, eps, fax, ico, jpeg, pcx, hdf, and many more.

Usage Notes

1. Because it requires a connection to an X-server, wi does not work when running grads in batch mode (-b option). A similar command that does work in batch mode is printim.
2. Some ImageMagick formats (tiff, png, mpeg, et al.) are not yet supported by grads. If a specified format is not recognized or supported, the image will be saved in MIFF, ImageMagick's native format. If a file name extension is not specified, GIF is the default.
3. Make sure no other window is on top of your grads graphics windows when issuing a wi command, because wi takes a snapshot of the current state of this window. If another window is partially covering your graphics window, your image file will contain the combination of these 2 windows.

Examples

To try out wi, display something on the graphics screen, and then at the ga-> prompt enter:

wi test.gif for writing a GIF file
wi test.jpeg for writing a JPEG file
wi test.bmp for writing a Windows BMP file

Bugs for Win32 GrADS Users

1. On Windows 95 systems, GradsHDF, the version built with the NCSA MFHDF library, has a subtle bug when reading certain 16-bit (short) packed NetCDF files (e.g. NCEP re-analysis files converted to NetCDF at CIRES/CDC). Although GrADS is able to produce a plot, it mistankenly produces very large values for a few grid points. Work around: use GradsNC in such cases. This problem has not been reported on Windows NT systems.
   
2. X Windows widgets built with gs scripts may miss/delay some X events (keyboard/mouse clicks). This problem appears to occur only on Windows 95; it has not been reported on Windows NT.
   
3. Athena widgets built with gui scripts: menu items become invisible when selected (MI/X Server only); some mouse delays on Windows 95.
   
4. wi has been reported to produce black and white GIF output on VGA systems with more than 256 colors. The workaround is to write a JPEG image, or to change your Windows display to 256 colors.