Fresh Fish 9/FreshFishVol9-CD2.bin/bbs/reviews/text.lha/text/AmigaTeX

Internet Message Format | 1992-05-06 | 15KB

From: Stewart Russell <[e-mail]>
Organization: The Amiga Online Review Column - ed. Jason L. Tibbitts III
Subject: REVIEW: AmigaTeX 3.1h
Keywords: application, page layout, typesetting, TeX
Path: menudo.uh.edu
Distribution: world
Newsgroups: comp.sys.amiga.reviews
Followup-To: comp.sys.amiga.applications
Reply-To: Stewart Russell <[e-mail]>

AmigaTeX is a full implementation of the TeX document preparation
and typesetting system for Amiga computers. It includes automatic
font generation using Metafont, virtual font mapping, PostScript
font support, and Encapsulated PostScript and IFF graphics
extensions. AmigaTeX makes good use of the Amiga's facilities,
and at US$300, offers superb value for money.

[
This review appeared in issue 12 of Jeff Walker's Just Amiga
Monthly (JAM) magazine, but in a slightly different form. I
tried selling this around most of the UK Amiga magazines, but
they weren't interested.

Feel free to use this review in any user magazine --- contact me
at the Reply To: address if you want some pictures. I don't get
around on Usenet much, so if you need me, use the Reply To:
address.

This review was not really intended for TeXperts, so please
excuse any totally obvious bits.

                                Stewart C. Russell
                                 Glasgow, Scotland.
]



Page layout is a skilled job. Anyone who has looked at a badly
DTP'd page will know this. Typesetting is a very skilled job,
especially when difficult layouts such as mathematical formulae
are involved.

Universities generally have a large computer installation, and
the facilities for publishing books papers written in house.
Computers are great at keeping track of large numbers of
measurements, which is essentially the basis of typesetting.


The TeX Cycle

TeX creates documents in its own special way. First, create your
source file; AmigaTeX has no text editing facilities of its own,
so you can use whatever editor you are happiest with.

Next, run your source through the TeX program to create a
device-independent (DVI) file, which contains all the page
layout information. Then preview the layout on the screen
viewer, which gives as good a picture of each page of the
document as is possible on a computer screen.

If you are happy with what you got out of the previewer, you
send the DVI file through one of the printer drivers. With luck,
you will have a document to cherish, output at the best quality
your printer can manage.

On a standard implementation of TeX, you would need to exit the
text editor before running TeX, then exit TeX before running the
previewer, and so on. With a 1 MB Amiga, you will probably be
forced to do the same with AmigaTeX.

With more memory, TeX and Preview can coexist. Preview responds
to signals from TeX, telling it when it is free to display a
page. With an ARexx-compatible text-editor, the whole package
becomes completely interactive, with errors in the source being
highlighted via a return code from TeX.


Since Usenet's graphics facilities tend to zero, it's not worth
including any TeX source or output here. Wander across to a
university library, and flick through some books on TeX. You'll
see what TeX source looks like, and more importantly, the superb
results it can create.


Macros

TeX requires macro packages to become usable. AmigaTeX comes
with two general purpose packages, Plain and LaTeX. Plain TeX
allows control over every aspect of the page layout. Sometimes
this means that the document gets so full of command sequences
that it becomes impossible to read.

LaTeX tries to maintain the flow of the document. It lacks some
of the powerful primitive commands of Plain TeX, but has high
level functions such as automatic section numbering, citation
databases, instant footnotes and index generation. It's what
most people use first, because it is straightforward to use.

A common criticism of TeX documents is that they all look the
same. With LaTeX, this is intentional; a standard document such
as a PhD thesis should be uniformly laid out, since it is the
content and not the presentation which is to be considered. Many
TeX documents look the same because many users never bother to
learn the more complex structures required to create new
layouts; the power is there, if only people looked for it.

TeX treats words as boxes, which are stuck together with glue
that is free to stretch or shrink by a set amount. The lines of
text, which can be independent of the lines on the input file,
are also in boxes which can move about very slightly according
to the current glue settings.

Words cannot stretch or shrink, but they can be hyphenated
across two lines. TeX has some very clever rules about this, and
manages to hyphenate most instances correctly. A hyphenation
dictionary is used for those difficult words.


Fonts

TeX uses a very elegant set of vector fonts, all designed for
maximum readability at their design scale. These fonts are
defined in units smaller than the wavelength of visible light,
so no advance in phototypesetting will ever render TeX fonts
obsolete.

The Computer Modern series of fonts created by Donald Knuth are
designed to be pleasing to the eye, without being simply
derivatives of the existing classics. Since TeX is for serious
publications, they are only available in sizes ranging from 5 to
17 points, all fully hinted, with an inch-high font for
headlines. Scaling to any size is possible, but gross font
scaling is not recommended, since the character stroke widths
look correct at sizes close to the design scale.

TeX does not use the vector fonts directly, since it must print
to some sort of raster device. Compressed bitmap versions of the
vector fonts are used, since there is approximately ten minutes
calculation (on a standard A500) involved in generating one font
at a given resolution.

These fonts are what make up the bulk of the AmigaTeX
distribution. There's around six megabytes of fonts with the
basic package alone, more with each printer driver. Each font
disk is colour coded, and AmigaTeX asks for them by name as it
requires a certain font. A cache of these font bitmaps is built
up on the hard disk, speeding up print times if the font is
needed again.

If you wish to use a strange sized font, AmigaTeX will ask you
if you wish it generated in the Previewer. If you really need
the font, the Metafont font generator is launched, and the font
will appear in the fullness of time. Metafont isn't required too
often once a mature cache has been established, so the time
delay can be lived with.

Metafont can also be used to design your own fonts. It uses a
straightforward ASCII language to do this, the intricacies of
which are explained in another book by Prof. Knuth. Like TeX, it
is powerful, and easy to use once you understand its way of
doing things.

The latest version of AmigaTeX is compliant with TeX 3.1, which
implements virtual fonts. A virtual font can be made up of parts
from any other font - you could have upper case taken from a 10
point serif font, and lower case using the upper case characters
from an 8 point set, giving a neat small caps font.

One of the neater uses for virtual fonts is to allow the use of
PostScript fonts in AmigaTeX documents. Both Type 1 and Type 3
fonts are supported, the former having anti-aliasing `hints' to
give better output quality. Fonts produced by Adobe Systems are
very well defined, but do not have the extreme precision of TeX's
own. They do have the distinct advantage of being rendered very
quickly (two minutes per font) and can be used totally
transparently by AmigaTeX. Virtual font bitmaps are cached like
any other TeX font, so rendering is a once-only delay.


Graphics

Plain TeX (and LaTeX) have only very simple line drawing
commands. To counter this, TeX has an extremely powerful command
called \special, which is so powerful that TeX ignores it
completely. It is passed intact to the DVI file, and it is up to
the printer driver to do something with it. It is in this way
that AmigaTeX can render IFF and Encapsulated PostScript
graphics into a predefined box.

Adrian Aylward's `Post' PostScript interpreter is use