JavaSketchpad — a brief introduction Sebastian Lisken


Abbreviations: JSP = JavaSketchpad, GSP = The Geometer's Sketchpad

JavaSketchpad is an applet that displays geometry in dragging mode -- constructions can't be modified.

Constructions are related to those of The Geometer's Sketchpad, but not strictly. Not all of GSP's features are supported (and a few constructions of JSP are not in GSP).

Constructions are given to the applet not as a GSP file, but in the applet's own construction language.

Create constructions in two ways:

  • Take a GSP file and treat it with the GSP HTML converter (you will have to edit the resulting HTML file if you want to use your local copy of the applet or if you want to add any HTML surrounding the applet)
  • or write your HTML from scratch, adding the JSP code by hand -- to support this method, I have produced my jsp.awk script which enhances the language and takes care of technicalities (see below)
  •  Provide the applet either by linking to keypress, or my pages, or your own copy (the applet parameters CODEBASE and ARCHIVE must be set accordingly)


    Produce HTML code containing a new (pseudo) tag named <JSP> -- I suggest to store this in files with a .jsp extension

    Put your construction (and set options) between the <JSP> and </JSP> tags

    The construction language is simple, defined in the JavaSketchpad Construction grammar and enhanced by jsp.awk with named objects, backreferences and macros

    An awk script (hence the name) takes the pseudo-HTML file (containing <JSP>...</JSP> tags) and converts it into standard HTML (containing <APPLET>...</APPLET> tags and not including jsp.awk's language enhancements)


    GSP: The Geometer's Sketchpad and demo download page

    JSP: JavaSketchpad Center and Download Center (applet classes and GSP converter)

    jsp.awk: my pages (always under development, comments very welcome)

    Examples: Results of a seminar where didactic Web pages were produced using GSP and JSP (not jsp.awk) and an introduction to trigonometry — both in German

    Cabri, the main alternative: Homepage, Demo Download and CabriJava, the applet that displays Cabri files saved with the full version of Cabri. CabriJava requires a Java 1.1 compatible browser (on most systems, Netscape from version 4.06, Internet Explorer from version 4, HotJava from 1.1.4 - see the compatibility page for details).

    Sebastian Lisken, 6 May 1999