[Groff] Re: new grohtml patches

[Werner LEMBERG]

> At the user level the patches provide:
> 
>   + much improved horizontal alignment.
>     This results in much neater manual page rendering imho..
>   + added the new .HEAD macro in www.tmac which allows users
>     to specify style sheets.
>     See doc/webpage.ms for an example. Also supplied is a trivial
>     style sheet for the web page.
> 
> "Under the hood" the patches implement the Lemberg[1] algorithm for
> preserving the troff state in diversions (many thanks Werner!).
> This information is passed through to post-grohtml which then
> accurately (I hope..) understands how troff is formating the
> document. As a result less html specific modifications are required
> inside macro files.
> 
> There is still an obvious bug in the vertical alignment in that
> spaces are present in between each table row and to paraphrase
> Dijkstra at least several bugs that I'm unaware of :-)

Very nice!  I'll apply them in the next few days (hopefully).  Some
comments, based on pic.ms.  It looks like those buglets can be fixed
easily:

. pic-6.html: Suddenly all paragraphs have

    <font color="#000000"> .... </font>

  (after the image with colour).  I think there should be some code
  to suppress this.

. The captions of figure 6-5 and figure 6-6 (and many others) are
  centered by grohtml itself.  I think this shouldn't be done -- the
  html browser will do it by itself.  Additionally, each centered line
  is envelopped by <p> ... </p> which adds ugly vertical space.

  Maybe the line length should be set to an `infinite' value?

. Sometimes, indentation is lost.  For example, look at pic-16.html.
  The line

    for variable = expr1 to expr2 [by [*]expr3] do X body X

  should be indented.  I'm not sure whether this is a problem in
  grohtml or missing support in the ms macros.

. On the last page, pic-23.html, I see

    [ prev | next | top ]

  which should be

    [ prev | top ]

  instead.  A similar problem can be seen in pic-1.html.

. groff.css isn't mentioned Makefile.in.  It should probably be
  handled similarly to grnexmpl.g, this is, copied from $(srcdir) to
  the current directory if srcdir != builddir.


A completely different buglet can be seen after 

  groff -e -man -Thtml groff_diff.n > groff_diff.html

Have a look at the documentation of the `Dp' drawing command.  The
small images representing dx1, dy1, etc. aren't properly aligned
vertically.  We probably have to modify eqn so that it makes troff
emit the `depth' (in the TeX sense) of an equation box as a tag -- the
change to eqn is trivial since it already emits \x with the proper
depth of that box.


    Werner