GDIT - GD InTpreter

Description

gdit is a simple interpreter for Thomas Boutell 's gd library. It can be used in preference to a high level language such as 'C' or the tcl interface to gd. gd provides a set of functions for creating CompuServe GIF files. GIF is the native file format for web browsers.

gdit Provides a useful set of features including:

gdit is not a generalised drawing package. It is designed to be used in Web CGI scripts where there is a set of known geometric data to be plotted. It can also be used from the command line to perform such chores as identifying and setting background colors on transparent GIFs.

History

I wrote gdit over a few weeks in March/April 1995. I decided to use bison and flex because they seemed to provided the most powerful environment for building the front end. I also have them running on both my NeXT and NT machines. Unfortunately I have neither used these tools before nor do I have any proper documentation other than some course notes copied down in '85 during a Computer Science lecture. I therefore apologize to any true disciples and would be very open to incorporating improvements. Anyway the whole thing seems to work fine.

As is often the case, gdit started out as a quick hack to solve a small problem, this was version 0.9 and seemed like the idea might have a wider audience. This version is a complete redesign of the earlier program and supports most of the features of the gd library.

New Features

  1. Can write GIF File data to the standard output stream. See example PERL scripts for usage.
  2. Support for reading X bitmap files.
  3. Script and Image files can be supplied on the command line.
  4. Allow comment strings to be written to GIF files.

Requirements

If you are building the UNIX version you will require the gd library. This must be obtained separately from gdit. gdit will build with the 'standard' UNIX yacc and lex tools. GNU provide versions of these tools called bison and flex . gdit is gnu preferred but 'yacc a son gui', as they say. The MS Windows 32 bit version is available as an .exe, no batteries required. This version was built using MSVC 2.0, you can also rebuild gdit.exe with the UNIX sources for gd library and gdit, you will require the GNU ports of bison and flex.

GDIT has been built on Sun, Linux PC, Windows NT, Windows 95, AIX and SGI systems.

License Terms

gdit is copyright 1995, David Harvey-George. Permission is granted to copy and distribute this work provided that all copyright notices remain intact. That means you can put it on your FTP site or distribute it on CDROM or other media without charge.

Use: gdit is free for none commercial use. However neither gdit or gd library is in the public domain. Copyright is retained by each holder.

Warranty

This program is distributed in the hope that it will be useful but without any warranty, without even the implied warranty of merchantability or fitness for a particular purpose.

Limitations

gdit only supports 1 output image (the current image) and 1 brush and tile image.

Future

eg:

set brush rook.gif

line 20 20 20 20 brushed

Given the legal difficulties surrounding GIF a new standard called PNG has been proposed. This is a 24 bit graphics format featuring a better compression algorithm but supporting useful GIF features such as interlacing and transparent colors. If the gdlibrary is ported to PNG it is hoped that gdit can be moved to this new standard without too much difficulty.

GDIT Language Specification

Bug List

Demonstration

Other Sources

Credits and license terms

gd 1.1.1 is copyright 1994, Quest Protein Database Center. You must obtain gd separately from gdit. See the documentation for full terms.

gdit v1.4 is copyright 1995, David Harvey-George and is based on v 1.2 of gd library.


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Last Updated: November 27, 1995. © 1995 DB Harvey-George, ITCP