Tcl, Tool Command Language, is a widely available free environment originally intended for 'glueing together' command line tools and fitting them out with a graphical user interface. Tk is a graphical user interface (GUI) library
complementing Tcl. Tk proved so popular that it now ships with all distributions of Tcl. Today Tcl/Tk is used for applications as different as air traffic control systems, bank administration services and... the Huygens Software.
Thus, Huygens Software is based on an solid, proven, well-documented and well-maintained programming language. One of the pleasant side effects of the use of Tcl, in contrast to vendor-specific macro languages, is the availability of a good number of excellent books and websites on Tcl. See for example http://www.tcl.tk/ or http://en.wikipedia.org/wiki/Tcl
In Tcl Huygens the standard Tcl interpreter is extended with image processing commands, and commands to control the general behavior of the Huygens Compute Engine (CE). Next to the basic Tcl command set Huygens Scripting also includes the Tk command set which allows you to create graphical user interfaces from scripts.
Useful libraries can be found, for example, in http://tcl.tk/software/tcllib/.
Currently the Huygens Software uses Tcl-Tk 8.6. The supported commands are listed in Tcl Tk Commands.
Standard documentation can be found in http://www.tcl.tk/man/.
A Tcl programming style guide can be found here.
See the basics of Tcl and the Huygens extensions for handling images in Tcl Huygens.
There are quite a number of books on Tcl/Tk. Below we list only the lucid book on Tcl by John Ousterhout, and the encyclopedian book written by Brent Welch et al:
- Tcl and the Tk Toolkit by John Ousterhout, ISBN: 0-201-63337-Z, Addison-Wesley, New York.
- Practical Programming in Tcl and Tk (4th Edition) by Brent Welch, Ken Jones, Jeffrey Hobbs, ISBN: 0-13-038560-3, Prentice Hall PTR.