On Sat, 19 Feb 2011, Peter Dyballa wrote: > XeTeX (and original TeX) do not put SPACE characters into the output, i.e., if > a SPACE glyph would exist in a font it is not used to separate words or such.
I'm well aware of that. I explained it myself on this very list a few days ago in answer to someone else's question about word boundary detection in OpenType features. However, even though XeTeX and original TeX do not send space glyphs to the output, they still need to know how wide an interword space should be for each font, so that they know where to put those non-space glyphs they do send. With an original-TeX font, whether the engine is TeX or XeTeX, that information would be in the TFM file and loaded into fontdimens 2, 3, and 4. With an OTF font, it appears that XeTeX looks at the "space" glyph in the font - even though it will not send that glyph to the output - and puts the width of that glyph into fontdimen2. And that's fine as far as it goes. The problem is that XeTeX also adds stretchability and shrinkability to the word space, which is an inappropriate thing to do when the font is monospace, and there doesn't seem to be a way to remove the stretchability and shrinkability in a way that will survive the LaTeX font-size commands. A side issue is that it also hardcodes a puntuation space that is much too small, in \fontdimen7 - I asked about that here last month - but that issue is easier to work around and would probably be solved by the same things that could solve the stretchability issue. > Presumingly the space between two words is comprised of the right bearing of > the right-most character of the left word + some inter-word space from TeX + > the left bearing of the left-most character of the right word. Only this > inter-word space is effected. Yes, and that "some inter-word space from TeX" is, in the case of OTF fonts with XeTeX, equal to the width of the space glyph plus a hardcoded proportion of stretchability and shrinkability. But it's not important that the main size comes from the space glyph width; the issue is the stretchability, which seems not to come from the font but to be provided by either the engine or the fontspec package. (I think it comes from the engine, but couldn't find it in the source code when I looked just now.) > Instead of exotic fonts you can use from TeX Live 2010 the GNU Freefonts in: No, I can't. The document in question is a type specimen, and written in a mixture of English and Japanese. Using a different font would defeat the entire purpose; and it should be obvious that "use a different font!" is not, in general, an acceptable solution to font-support problems. Furthermore, the fonts you just named don't contain any Japanese or Han-unified characters and therefore would be useless for my document even if I were free to change the font. But even if I pretend that the GNU FreeFonts are acceptable, when I try it with the OTF version of FreeMono XeTeX still makes the interword space stretchable after each LaTeX size command. Do you have an installation that does not do that - where you can use a plain LaTeX font size command and have the interword space afterward be scaled to the new size but NOT stretchable? If so, I'd really like to know the version numbers and the TeX code you're using to accomplish that. A major goal of XeTeX is to support languages other than English - including languages such as Japanese that are written in the Han script. 地球の人々は全部英語を読みません。Typesetting in such languages is traditionally monospace; "don't use monospace fonts" or "accept that spacing will be stretchable and therefore wrong when you use monospace fonts" are not limitations XeTeX can sustain. "You must reset the spacing after every size change" is a workaround I can live with in the short term, but it is not a solution. It seems clear to me that this is a bug, though I'm not sure yet whether it's better considered as a bug in the XeTeX engine or in the fontspec package, because it's not clear where the stretchability is being set. -- Matthew Skala msk...@ansuz.sooke.bc.ca People before principles. http://ansuz.sooke.bc.ca/
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