From: "Thomas A. Schmitz" <thomas.schmitz@uni-bonn.de>
To: Hans Hagen <pragma@wxs.nl>,
mailing list for ConTeXt users <ntg-context@ntg.nl>
Subject: Re: xml and lua again
Date: Fri, 28 Oct 2011 12:48:38 +0200 [thread overview]
Message-ID: <4EAA8886.40204@uni-bonn.de> (raw)
In-Reply-To: <4EAA6E5A.8010606@wxs.nl>
On 10/28/11 10:56, Hans Hagen wrote:
> Just switch to philosopher mode for a while and ask yourself what
> implications that would have in the rather fuzzy world of printing.
>
> What is a 'real' dimension? What we call points (pt) is in other
> application also called points but happens to be basepoints in our
> universe (bp). Also, imagine that in good american tradition the
> dimension would have been inches while we all moved on to meters ...
>
> So, Knuth foresaw this (and also wanted predictable calculations and
> wanted to avoid unportable floating points) so he came up with his own
> unit: scaled points. So, a \dimen is just a \count but consider it
> tagged to show you pt for convenience when printed (\the) and the parser
> permits you to enter these numbers as pt/bp/dd/cc/cm/mm etc.
>
> At the lua end all are just integers (with some limited size but that
> might change as Taco and I want to play a bit with adding a couple of
> bytes and see to what extent that will break things).
>
> In metapost the internal unit is bp (because it targets at postscript)
> and there cm, mm etc are just variables that one multiplies with so
> there you can change the universe by just saying "in := cm".
>
> Skips are another story (not to speak of boxes as we do have a dimendef
> but not a boxdef of inserts which are yet another class of animals).
Thanks for this philosophical explanation - I guess I'll have to reread
these passages in the TeX book. I'm looking forward to your experiments :-)
Thomas
___________________________________________________________________________________
If your question is of interest to others as well, please add an entry to the Wiki!
maillist : ntg-context@ntg.nl / http://www.ntg.nl/mailman/listinfo/ntg-context
webpage : http://www.pragma-ade.nl / http://tex.aanhet.net
archive : http://foundry.supelec.fr/projects/contextrev/
wiki : http://contextgarden.net
___________________________________________________________________________________
next prev parent reply other threads:[~2011-10-28 10:48 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-10-22 16:46 Thomas A. Schmitz
2011-10-23 14:04 ` Peter Rolf
2011-10-23 14:37 ` Thomas A. Schmitz
2011-10-23 15:25 ` Peter Rolf
2011-10-23 18:15 ` Peter Rolf
2011-10-24 10:17 ` Hans Hagen
2011-10-24 12:18 ` Thomas A. Schmitz
2011-10-24 12:26 ` Hans Hagen
2011-10-24 17:00 ` Thomas A. Schmitz
2011-10-24 18:48 ` Hans Hagen
2011-10-25 9:43 ` Thomas A. Schmitz
2011-10-25 10:10 ` Wolfgang Schuster
2011-10-25 10:17 ` Hans Hagen
2011-10-25 10:27 ` Thomas A. Schmitz
2011-10-27 9:23 ` Thomas A. Schmitz
2011-10-27 9:53 ` Wolfgang Schuster
2011-10-27 10:32 ` Thomas A. Schmitz
2011-10-27 11:05 ` Hans Hagen
2011-10-28 6:23 ` Thomas A. Schmitz
2011-10-28 6:37 ` luigi scarso
2011-10-28 6:43 ` luigi scarso
2011-10-28 6:44 ` Patrick Gundlach
2011-10-28 6:55 ` Thomas A. Schmitz
2011-10-28 8:35 ` Wolfgang Schuster
2011-10-28 8:59 ` Hans Hagen
2011-10-28 8:56 ` Hans Hagen
2011-10-28 10:48 ` Thomas A. Schmitz [this message]
2011-10-28 11:23 ` luigi scarso
2011-10-28 11:42 ` Hans Hagen
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=4EAA8886.40204@uni-bonn.de \
--to=thomas.schmitz@uni-bonn.de \
--cc=ntg-context@ntg.nl \
--cc=pragma@wxs.nl \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).