ligatures?

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Adam Lindsay

12 May 2003 12 May '03

2:28 p.m.

TeXnicians, Once again, I'll stick my neck out showing my pure TeX ignorance. Are there ConTeXt commands for adding ligatures to the usual set (ff, fi, etc.)? Where in the chain are these characters (f + i) grouped and associated with the 'fi' character to be output? I'd like to be able to take advantage of some extended ligatures with my pro fonts, but it seems that if users have to enter the ligatures as \Thligature or whatever, they would be of very limited use. thanks in advance, adam -- =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-= Adam T. Lindsay atl@comp.lancs.ac.uk Computing Dept, Lancaster University +44(0)1524/594.537 Lancaster, LA1 4YR, UK Fax:+44(0)1524/593.608 -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-

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Bruce D'Arcus

12 May 12 May

2:57 p.m.

On Monday, May 12, 2003, at 10:28 AM, Adam Lindsay wrote:

...

Are there ConTeXt commands for adding ligatures to the usual set (ff, fi, etc.)? Where in the chain are these characters (f + i) grouped and associated with the 'fi' character to be output?

IIRC, look in the encoding files; in other words, at the level of TeX itself. To add ligs, though, you need to use slots. Because of the 256 character limit, this means you have to throw out other glyphs to get the extra ligs AFAIK. Bruce

Bill McClain

3:01 p.m.

On Mon, 12 May 2003 10:57:52 -0400 "Bruce D'Arcus" wrote:

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To add ligs, though, you need to use slots. Because of the 256 character limit, this means you have to throw out other glyphs to get the extra ligs AFAIK.

I wonder: the vf files define ligatures also; run vftovp on one and look at the LIG entries in the LIGTABLE section. Could this be used to add arbitrary number of new ligatures, or convenient coding for some glyphs? Hoenig has examples of this sort of thing in _TeX Unbound_. I've wanted to experiment with virtual fonts for a while, but am daunted by fontinst. -Bill -- Sattre Press Pagan Papers http://sattre-press.com/ by Kenneth Grahame info@sattre-press.com http://pp.sattre-press.com/

Bruce D'Arcus

3:25 p.m.

On Monday, May 12, 2003, at 11:01 AM, Bill McClain wrote:

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I've wanted to experiment with virtual fonts for a while, but am daunted by fontinst.

Here's a really good new tutorial: http://lehman.virtualave.net/files/ltxfonts.pdf Bruce

Edmund Lian

3:43 p.m.

New subject: Dumb newbie question about UTF-8 support

Hi All, I'm a newbie experimenting with TeX/ConTeXt as a cross-platform MS Word/Quark/InDesign/etc. substitute. I like what I've seen so far, so I moved on to exploring how well it would support a multilingual situation. And this is where I started to get confused... I need to be able to use both Traditional and Simplified Chinese, English and perhaps one or two other languages. The problem with Chinese is that there are several different encoding standards--Big5, GB, HZ, etc. I'm trying to avoid the mess involved in moving documents between Big5 and GB by going to UTF-8 as a standard. Despite all my Googling however, I still haven't been able to establish a suitable tool chain to process these documents using TeX/ConTeXt... some of my initial points of confusion are: 1. TeX. Apparently it is not UTF-8 capable, hence Omega and NTS. However, I see Unicode extensions for LaTeX. How is this possible, and what is the analogous situation for ConTeXt? 2. ConTeXt. I see passing references to some kind of UTF-8 extension, but cannot find documentation on it. mchinese.pdf also mentions this in passing. Is it possible to feed UTF-8 documents to ConTeXt? 3. Font installation. mchinese.pdf describes how to install Chinese fonts, but the tools used are not available in some of the environments that I've been using (Mac OS X, Debian/GNU Linux, etc.) I did come across ttf2tex, but there's no mention of this in mchinese.pdf. Where can I find more current instructions for installing fonts for ConTeXt? Finally, I wonder if anybody else finds the pragma-ade.nl site very hard to use/navigate because of the heavy use of PDFs? Some of the in-document links that call up other PDFs are broken. And, if the browser isn't set up right, it tries to download the PDF rather than opening it in-place. I can't help thinking that a more HTML-oriented site would actually improve navigability and utility... ...Edmund.

Patrick Gundlach

3:03 p.m.

"Adam Lindsay" writes:

...

I'd like to be able to take advantage of some extended ligatures with my pro fonts, but it seems that if users have to enter the ligatures as \Thligature or whatever, they would be of very limited use.

Adam, make use of the "Virtual Fonts" feature in TeX and the backends. How did you install your fonts? You should have some .vf files for your fonts and you can access the contents of them with vftovp (convert back with vptovf) and just add ligature information. See Knuth's "More fun for Grand Wizards: Virtual Fonts" available on ctan or in Knuth's book "Digital typography". (Hope I got the title of the article right.) Virtual Fonts are real fun to play with! It is (imo) one of the best reason to use TeX :) It is completely transparent to the users, no need to say \Thligature or so. Patrick

Bruce D'Arcus

3:46 p.m.

On Monday, May 12, 2003, at 11:03 AM, Patrick Gundlach wrote:

...

make use of the "Virtual Fonts" feature in TeX and the backends. How did you install your fonts? You should have some .vf files for your fonts and you can access the contents of them with vftovp (convert back with vptovf) and just add ligature information.

The strategy he used does not use virtual fonts. It involved running afm2tfm (via texfont) on the afms to extract the glyphs using different encodings. Conceptually this is pretty straightforward. I'm not sure (because I've never done it) what would be involved in extending this installer to support adding ligs via vfs... Bruce

Patrick Gundlach

9:27 p.m.

"Bruce D'Arcus" writes:

...

...
make use of the "Virtual Fonts" feature in TeX and the backends. How did you install your fonts? You should have some .vf files for your fonts and you can access the contents of them with vftovp (convert back with vptovf) and just add ligature information.

The strategy he used does not use virtual fonts.

Who is "he" in this case? Adam?

...

It involved running afm2tfm (via texfont) on the afms to extract the glyphs using different encodings.

But afm2tfm gives you the vf's! And how can you reencode a font without vf's? Are you doing this in the mapfile?

...

Conceptually this is pretty straightforward. I'm not sure (because I've never done it) what would be involved in extending this installer to support adding ligs via vfs...

Just take the fi as an example. Patrick

Bruce D'Arcus

10:04 p.m.

On Monday, May 12, 2003, at 05:27 PM, Patrick Gundlach wrote:

...

...
The strategy he used does not use virtual fonts.

Who is "he" in this case? Adam?

Yes. And me too.

...

...
It involved running afm2tfm (via texfont) on the afms to extract the glyphs using different encodings.

But afm2tfm gives you the vf's! And how can you reencode a font without vf's? Are you doing this in the mapfile?

OK, I don't fully understand virtual fonts, but let's take an example: You have a font with 1,000 + glyphs (an OpenType Pro font). You take texnansi as your base encoding, and create a variant encoding that replaces regular figures with old-style. You run afm2tfm on the afms using this variant encoding, and it creates a tfm with all of the necessary metric information. When you typeset, you tell it to use texnansi so that TeX uses the old-style figures. No need for virtual fonts (as it was explained to me, you will put TeX into infinite loop if you actually refer to the vfs in this case, but I don't understand exactly why; I think because the vf refers to the tfm, which refers back to the vf.). Bruec

Adam Lindsay

3:54 p.m.

Patrick, Bruce, Bill, Thanks a lot for the excellent suggestions. I had completely avoided Virtual Fonts before (even when making "new" math fonts), because I thought it would be too much of a big topic to tackle (more that it would be too interesting, rather than too difficult :). After this enthusiastic response, however, I'll be giving the topic a closer look. Thanks for the Lehman link, Bruce. So, am I right in concluding that ligatures are *only* handled by the output routine? There's no way of using ConTeXt to map my normal text input ('i' followed by 'j') to the already-defined \ijligature? Cheers, adam Patrick Gundlach said this at Mon, 12 May 2003 17:03:01 +0200:

...

"Adam Lindsay" writes:

...
I'd like to be able to take advantage of some extended ligatures with my pro fonts, but it seems that if users have to enter the ligatures as \Thligature or whatever, they would be of very limited use.

Adam,

make use of the "Virtual Fonts" feature in TeX and the backends. How did you install your fonts? You should have some .vf files for your fonts and you can access the contents of them with vftovp (convert back with vptovf) and just add ligature information. See Knuth's "More fun for Grand Wizards: Virtual Fonts" available on ctan or in Knuth's book "Digital typography". (Hope I got the title of the article right.) Virtual Fonts are real fun to play with! It is (imo) one of the best reason to use TeX :) It is completely transparent to the users, no need to say \Thligature or so.

Patrick _______________________________________________ ntg-context mailing list ntg-context@ntg.nl http://www.ntg.nl/mailman/listinfo/ntg-context

-- =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-= Adam T. Lindsay atl@comp.lancs.ac.uk Computing Dept, Lancaster University +44(0)1524/594.537 Lancaster, LA1 4YR, UK Fax:+44(0)1524/593.608 -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-

Bruce D'Arcus

8:54 p.m.

If you want to get completely out of control (and I don't recommend this unless you really need the functionality): You can also use the ligature mechanism to access alternate glyphs. For example, you could set up the fonts so that *Z gives you the swash Z. The technique (though using Omega) is outlined here: http://www.tau.ac.il/~stoledo/Pubs/ps3.ps Bruce

Patrick Gundlach

9:41 p.m.

"Adam Lindsay" writes: Hello Adam, I am not a TeX expert, but I try to give an answer. Please anybody out there correct me.

...

So, am I right in concluding that ligatures are *only* handled by the output routine?

The ligatures defined by the font are handled by the paragraph breaking routine. Deep down inside the lion. The "output routine" (OTR) is something different.

...

There's no way of using ConTeXt to map my normal text input ('i' followed by 'j') to the already-defined \ijligature?

In order to parse the text so that ij is mapped to \ijligature, you probably have to make the "i" active and check if the next char is "j" and if yes, replace it with \ijligature. Don't think about it. Patrick

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Adam Lindsay
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Bruce D'Arcus
Edmund Lian
Patrick Gundlach

ligatures?

Adam Lindsay

Bruce D'Arcus

Bill McClain

Bruce D'Arcus

Edmund Lian

Patrick Gundlach

Bruce D'Arcus

Patrick Gundlach

Bruce D'Arcus

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