Using JGV

Installing JGV

To install JGV on your Web server, unpack the distribution file (either JGV.tar.Z, or JGV.zip). Inside the "JGV" directory that the unpacking process creates you will find several files, plus a subdirectory called "geom". The class files are inside subdirectories of the "geom" directory. Move the "geom" directory to some directory that is visible to your web server.

When you invoke JGV, make sure that the file "logo.gif" is in the same directory as the HTML file containing the applet tag.

Applet tag

To use JGV in a Web page you create an "applet tag" in an HTML file that looks something like the following:

    <applet
      code="geom.jgv.JGVApplet"
      codebase=../..
      width=200 height=200>
    <param name="background" value="0x000000">
    <param name="file" value="data.oogl">
    </applet>

The "code=" line gives the name of the applet to invoke and should appear exactly as above. The "codebase=" line should give the pathname on your server of the directory into which you installed the "geom" directory in the installation process above; this pathname can be relative to the current directory (the one containing the HTML file you're writing), or it can be an absolute path from the root of your Web tree. The "width=" and "height=" line should give the dimensions, in pixels, that you want the JGV applet to take up in the Web page.

Following the initial "<applet ...>" tag there can be a number of parameters to be passed to JGV. Each parameter should be given in the form

    <param name="NAME" value="VALUE">

where NAME is the name of the parameter, and VALUE is the value that you want it to have. The parameters that JGV recognizes are:

background: the background color, specified as 6-digit hexadecimal integer
file: the name of a data file to load; this file should be stored on your server in the same directory as the HTML page
geom: the actual geometry specification. This lets you specify the geometry directly in the HTML file, rather than having it download another file from the server. If you use this, omit the file parameter. NOTE: in the value field for the geom parameter you must terminate each line with a semicolon. This is necessary because Netscape eliminates newlines from parameter values. Also, avoid using tabs; Netscape seems to eliminate them too. Use spaces instead. Here's an example of a JGV applet tag using the geom parameter.

Geometry formats

JGV recognizes a restricted subset of the OOGL file format used by Geomview. Specifically, JGV

recognizes the OFF and VECT types (but not their higher dimensional versions, 4OFF, 4VECT, etc)
recognizes the LIST and INST object types for building composite objects
correctly parses but ignores vertex color information in OFF objects (it does correctly handle face colors, though)
does not recognize appearances
does not recognize handles (objects named with "define" or "unit")
does not recognize the binary OOGL formats

For complete details of the OOGL file format, see the OOGL documentation.

The Geometry Center Home Page

Comments to: webmaster@geom.umn.edu
Created: Sep 16 1996 --- Last modified: Thu Jan 29 14:59:02 1998