Here are pointers to documentation on the graphics extension used on the course. The extension requires a Unix/X11 system; it does not work on Windows.
The graphics extension uses a program called xdraw, which reads commands and draws things on a window. You can use it directly from Scheme in Niksula. The Scheme interface is described here:
(You don't need to load the file xdraw-mzscheme.scm that the documentation talks about, and you don't need to set *xdraw-path*. This is done automatically in Niksula, so you can just evaluate (new-xdraw) to open a new graphics window.)
The available commands and their syntax is described on the xdraw manual page. You probably only need to read the COMMANDS section of the manual page.
The quickest way to learn to use the graphics extension is probably to look at the examples in the README.Scheme file (above). Please try out the examples with Niksula's Scheme interpreter.
The syntax of color and font names is described on the X(1) manual page (sections COLOR NAMES and FONT NAMES):
The xdraw(1x) manual page also refers to quite a few other manual pages. You usually don't need them, but if you do, you should be able to view them in Niksula with the "man" program. For example, "man XDrawArc" should display the XDrawArc(3x) manual page.
There are short examples of using xdraw in the README.Scheme file above. Below is a link to a longer example. Please note that it's not very well commented, and probably useful mostly as a demonstration of a more complex style of graphics. The short examples in README.Scheme are probably better for learning to use the graphics extension.
This page is currently maintained by Timo Lilja. Last updated on Sep 25th, 2001.