driver — select a graphics driver
driver(driver_name) current_driver=driver()
This function is used to select a graphics driver, or with no arguments
to get the current graphics driver name.
Most of the time, a user can ignore this function and change the driver
by calling high level functions such as xbasc.
The selected driver can be one of the followings:
output to the screen of the computer.
output into Postscript format.
output to the screen of the computer. Same as X11.
output into XFig format.
output into Gif format.
output into PPM format.
To convert "GIF" or "PPM" files to other image format or for building animation one can use the "convert" program for ImageMagic (http://www.imagemagick.org/)
For example if one has generated a sequence of Gif files named img*.gif it is possible to build an animated Gif file (named anim.gif) by
convert -delay 10 img*.gif anim.gif