[Groff] Announcing the new html driver

[Gaius Mulley]

Hello fellow groffians,

I've finally emailed Werner some patches for the first cut of
the new html device driver. I've refrained from sending them
to the list since they are 76k and require moving the source
tree a little. The new device driver is a complete replacement
for the old driver and is now invoked as -Thtml whereas
the old driver is invoked via -Thtml-old.

[ if you want to try this now you can down-load a patch applied
  gzipped tar cvs src tree from:
  ftp:floppsie.comp.glam.ac.uk/pub/groff/groff-html.tar.gz
]

[ example output exists under
  http:floppsie.comp.glam.ac.uk:Glamorgan/gaius/web/groff.html
]

Assuming the patches are accepted :-) then the feature list
for the new device driver is as follows:

+ simpler implementation!

+ troff passes tag information through from the front end so that the
  back end device driver understands sections/titles/line breaks and
  no formatting (.nf .fi) requests.

+ troff runs twice once for html text and once for images (ps -> png).
  Thus all postscript features should work, for example encapsulated
  postscript. PSPIC works fine with -Thtml, without the need for any
  extra commands.

+ all images are transparent png files.

+ emitted html code is much easier to read - and passes w3 tidy
  (apart from omitting the alternative tag on images).

+ automatic section heading links are generated (and can be turned off
  via -P-l). (Also see -P-n).

+ automatic rules at the top and bottom of the document are generated.
  Likewise these can be turned off via -P-r.

+ resolution of the images can be altered via -P-i<number>. Where <number>
  is the number of pixels per inch.

+ renamed -markup to -mwww

+ section and numbered heading links can be placed anywhere at
  users request (including multiple occurrences if desired) using .LINKS

+ defaults to the html base size of 3 and then scales up and down from there.

Still to do:

- tags into needs to be placed into all other macro sets. I've only added
  them to -man and -ms
- tables need to produce html tables rather than png files.
- testing/thrashing though many different styles of input.
- the font descriptions R.proto needs checking. It was written with
  strict html-4.0 conformance in mind. I suspect that other ISO chars
  are understood by most browsers - but I've not included non html-4.0
  chars.
- I think that html.tmac could provide more character approximations
  maybe as a substitute for some lack of characters in html-4.0.
  I've not done this yet, due to time, and also wondering whether this
  is the correct way to go..
- probably more

I'd also like to say a huge `thank you' to Werner for coming up with the
new design..

enjoy,

Gaius