Bugs item #712, was opened at 2006-12-12 03:53 You can respond by visiting: http://sarovar.org/tracker/?func=detail&atid=493&aid=712&group_id=106 Category: hz Group: v1.40.0
Status: Open Resolution: Accepted Priority: 5 Submitted By: Robert (schlcht) Assigned to: The Thanh Han (hanthethanh) Summary: problems with \letterspacefont
Initial Comment: % Testing the new \letterspacefont, I found: % % (1) it's certainly not correct to have the spacing % relative to character widths (look at `minimal'!) % (2) everything's shifted to the right % (3) when trying to expand the letter-spaced font, I % get the warning `font should be expanded before % its first use' (even before its first use), and % then pdftex segfaults. \pdfadjustspacing2 \hsize13cm This is normal text This is normal text This is normal text This is normal text This is normal text This is normal text {\letterspacefont\lspfont=\font 1000 %\pdffontexpand\lspfont 20 20 5 autoexpand % segfault \lspfont This isn't normal text This isn't normal text This isn't normal text This is minimal text} This is normal text This is normal text This is normal text \bye ---------------------------------------------------------------------- Comment By: The Thanh Han (hanthethanh) Date: 2007-03-01 22:07 Message: Logged In: YES user_id=710 here is a patch that makes disabling ligature optional -- a keyword "nolig" would do that: \letterspacefont\y=\x 100 nolig ---------------------------------------------------------------------- Comment By: The Thanh Han (hanthethanh) Date: 2007-02-22 10:31 Message: Logged In: YES user_id=710 yes it sounds reasonable. Or we can extend the syntax of \letterspacefont so that if an optional keyword like 'nolig' is found then ligatures will be disabled. ---------------------------------------------------------------------- Comment By: Robert (schlcht) Date: 2007-02-22 03:54 Message: Logged In: YES user_id=2217 The current situation with regards to the lack of kerning of letterspaced fonts is not really satisfying. After some consideration, I therefore think it is actually better *not* to disable ligatures, and hence kerning, for letterspaced fonts. So I would propose to remove the line: set_no_ligatures(k); {disable ligatures for letter-spaced fonts} It is easy enough for the high-level interfaces (microtype, context) to (automatically) disable selected ligatures only, so that kerning for the rest of the characters is still available. What do you think? \letterspacefont\lsfont\font 100 \lsfont \tagcode\lsfont`f -1 VALID off -- \bye ---------------------------------------------------------------------- Comment By: The Thanh Han (hanthethanh) Date: 2007-02-02 14:54 Message: Logged In: YES user_id=710 the warning message can be removed. I left it there since I don't know what happens if a virtual font is loaded, used and then expanded and used again with font expansion. It should be alright to do so, but I am not very sure. Anyway, I will change the warning to be issued for non-virtual fonts only. It turned to be a design mistake that the \pdffontexpand primitive takes a base font and turns it to an expanded font. It would be better it was more like \letterspacefont, ie it should create a new font and leave the original font intact. ---------------------------------------------------------------------- Comment By: Taco Hoekwater (taco) Date: 2007-02-02 08:30 Message: Logged In: YES user_id=1608
I hope luatex will abolish with this nonsensical connexion of ligatures and kerns?
Yes. ligatures and kerns are totally separate in luatex. ---------------------------------------------------------------------- Comment By: Robert (schlcht) Date: 2007-02-01 20:02 Message: Logged In: YES user_id=2217 If the warning is misleading, should it not be removed? On a different matter: Since \letterspacefont issues set_no_ligatures, there won't be any kerning, either. There's no way around that, I guess? (I hope luatex will abolish with this nonsensical connexion of ligatures and kerns?) ---------------------------------------------------------------------- Comment By: The Thanh Han (hanthethanh) Date: 2007-01-04 16:59 Message: Logged In: YES user_id=710 The warning is misleading but harmless. The reason of the warning is that pdftex checks whether a font has not been used before expansion (its type has not been examined and is new/unknown yet). \letterspacefont sets the type of \y as a virtual font, thus pdftex thinks the font might have been used before. ---------------------------------------------------------------------- Comment By: Robert (schlcht) Date: 2007-01-04 01:40 Message: Logged In: YES user_id=2217 I'm a bit confused about the status of (3): letterspacing and expansion: When expanding a letterspaced font, pdftex issues the warning: ``font should be expanded before its first use'', but apart from that, I cannot see any problems -- the font is both letterspaced and expanded. Or is there a reason for the warning? \pdfadjustspacing2 \font\x=cmr10 \x \letterspacefont\y=\x 100 \y \pdffontexpand\y 20 20 5 autoexpand ... \bye ---------------------------------------------------------------------- Comment By: Martin Schröder (oneiros) Date: 2006-12-21 17:09 Message: Logged In: YES user_id=421 A patch for this will be included in the next version (1.40). ---------------------------------------------------------------------- Comment By: The Thanh Han (hanthethanh) Date: 2006-12-12 18:47 Message: Logged In: YES user_id=710 oops, I disabled ligature for letter-spaced font, but this should not affect the base font. Will have to rethink. Most likely the syntax will change like follows: \letterspacefont\f=cmr10 at 11pt 100 \f text ---------------------------------------------------------------------- Comment By: Robert (schlcht) Date: 2006-12-12 16:50 Message: Logged In: YES user_id=2217 % and here's % (4) ligatures will be broken up, not only in the % letter-spaced font (which is probably acceptable), % but in all subsequent uses of the base font, too fi\par {\letterspacefont\lspfont=\font 100 \lspfont fi}\par fi \bye ---------------------------------------------------------------------- Comment By: The Thanh Han (hanthethanh) Date: 2006-12-12 14:31 Message: Logged In: YES user_id=710 I fixed (1) and (2); (3) is disabled now, ie you cannot expand a letter-spaced font. Please wait for another release from Martin. ---------------------------------------------------------------------- You can respond by visiting: http://sarovar.org/tracker/?func=detail&atid=493&aid=712&group_id=106