- From: Steve Deach <sdeach@adobe.com>
- Date: Fri, 31 Oct 2008 15:01:32 -0700
- To: Asmus Freytag <asmusf@ix.netcom.com>
- CC: Martin Duerst <duerst@it.aoyama.ac.jp>, "KOBAYASHI Tatsuo(FAMILY Given)" <tlk@kobysh.com>, fantasai <fantasai.lists@inkedblade.net>, WWW International <www-international@w3.org>, Paul Nelson <paulnel@winse.microsoft.com>, Michel Suignard <michel@unicode.org>
Replies interleaved below. On 2008.10.31 14:30, "Asmus Freytag" <asmusf@ix.netcom.com> wrote: > On 10/31/2008 1:50 PM, Steve Deach wrote: >> Exactly what I said under WSA/WSR. In some languages, this is used for >> emphasis . > My point was that because they conflict visually, when WSA is used, > letterspacing should either not be permitted, should be contraction > only, or should be kept below a threshold that prevents it from being > confused with WSA. No, WSA is the emphasis usage. It is an explicit style override on a span of a fixed amount (basically CSS-2.0 letterspacing). It is applied first, before any line-breaking decision is made. If the line then requires justification, traditional letterspacing/wordspacing (as is in XSL & proposed in CSS3) is applied in addition. (see more detail below) >> >> There are ³country² differences, ³language² differences, ³script², and >> ³wild hare² (random designer-/instance-specific) differences in >> everything related to text composition (styling & layout). > Agreed - it is helpful, though, to amass as much detailed input on known > systematic differences in typical text usage conventions. I find that > much more helpful than merely saying "watch out - something may depend > on something". --Sorry, I don't understand the referents for the first sentence. I think you are saying that you can't "automate" this processing, which I basically agree with because you can't fully determine the aggregat of language/country/... combinations in a systematic manner -- Since at least one of these parameters is "wild hare" (and perfectly resolving reader/designer conflicts in locale is impossible), you need explicit options there may be for some of these styling decisions, because even in a well-defined locale 2 or more viable choices or the non-standard choice may be intended to attract attention (or other designer reason). --I'll answer the second sentence: In this case, all the adjustments are "additive". For any property that has a single value or an optimal value (in a min/opt/max triplet), the single/optimal value is applied before making the line-break decision; then the min/max values are used to determine a "window" on the break-point; then once the break is chosen, the min/max values are used to readjust the spacing to make the line justify. (Its been that way in traditional publishing systems for 32 years, at least.) > > A./ >> (However, 20+ years ago, no one was very careful about those >> distinctions; so I think I used [or intended to use] script/language >> in the message below to indicate the distinctions were fuzzy. The same >> comment applies to ³letter², ²character², vs. ³glyph²; so read my >> email using the traditional ³fuzzy² definitions vs. the current ones.) >> >> On 2008.10.31 12:46, "Asmus Freytag" <asmusf@ix.netcom.com> wrote: >> >>> An aside on "letterspacing": >>> >>> The use of this is language dependent! (Not just script dependent). >>> >>> In German, it the use of increased letterspace for e m p h a s i s >>> (like this) has traditionally been used with both Fraktur and roman >>> style fonts. The practice is apparently still alive and well, because >>> you find it use in electronic forums on the web - a rather modern use of >>> text. Letterspacing, unless kept below very tight thresholds, is >>> therefore c o n f u s i n g to readers expecting it to denote emphasis. >>> >>> Other Northern European languages may have similar issues, but I don't >>> have first hand knowledge of current practices. >>> >>> A./ >>> >>> On 10/31/2008 12:04 PM, Steve Deach wrote: >>>> Every few years this issues comes back up. Unfortunately, I can't >> find the >>>> rather long treatise I wrote the last time. >>>> >>>> In general, I agree with Martin, that one should use styling >> properties as a >>>> replacement for most of the "layout" uses of space characters (just >> as one >>>> should use tables in place of most uses of tabs). That said, I would >> like to >>>> briefly summarize the traditional (pre-DTP) handling of spaces and >> spacing, >>>> and comment on "what I believe" to be the correct handling. >>>> >>>> Second, I agree that the handling of letterspacing and wordspacing >> varies by >>>> script and in some cases usage within a script, due to historic/cultural >>>> differences in preferences/aesthetics, or specific readability >> requirements >>>> for the usage, and the aesthetic desires of the designer. >>>> >>>> >>>> >>>> This is a partial reconstruction of my prior emails on this topic. >>>> >>>> My terminology: >>>> "Spacing" an adjustment to the distance between 2 glyphs/characters. >>>> "Space" a character which has a width but no visible inked >> representation. >>>> "Letterspacing" an adjustment to the intercharacter spacing used for >>>> line justification. [This definintion differs from CSS's.] >>>> "Wordspacing" an adjustment to the width of an interword space, also >>>> used for line justification. >>>> "WhiteSpaceAddition/Reduction ( WSA/ WSR)" a uniform adjustment to >>>> intercharacter spacing that is applied for design purposes or >>>> emphasis . [This corresponds most closely to the CSS-2.0 definition >>>> of letterspacing. Most DTP applications call this "Tracking".] >>>> "Tracking" and adjustment to intercharacter spacing which varies by >>>> fontsize/pointsize that is used to increase readability when >>>> optical sizing is not provided by the font. [This traditional >>>> definition differs from that used in most DTP applications.] >>>> >>>> >>>> In setting Roman text: >>>> Letterspacing is not generally applied to Arabic (and other >>>> connected-letter scripts/languages, nor to connected letter >> ("script") faces >>>> in Roman-derivative scripts) >>>> Letterspacing is not generally applied to ideographic or similar >>>> monospaced scripts, nor to monospaced text in Roman-derivative >> environments. >>>> Traditional applications varied widely in the algorithms used for >>>> weighting how much of a justification adjustment was applied to >> wordspacing >>>> vs to letterspacing. Most modern systems treat them as >> linear-proportional. >>>> Traditional publishing applications were also at odds over whether the >>>> letterspacing adjustment AND the wordspacing adjustment should both be >>>> applied to the space/NbSp characters, but most modern systems apply >> both. >>>> The Unicode NbSp (u+00a0) character should be treated the same as the >>>> Unicode Space (u+0020). [In traditional publishing systems, these are >>>> variable width in justified lines and fixed width in "aligned", >> tabular, and >>>> math uses. However, some traditional publishing systems treat all space >>>> characters prior to the first non-space in a line as fixed width.] >>>> The FigureSpace (u+2007), and PunctuationSpace (u+2008) are treated the >>>> same way the corresponding figure '0' and punctuation period/full >> stop would >>>> be treated in the current layout context (justified vs >>>> aligned/tabular/math). >>>> Some traditional publishing systems had a quad-space and a >>>> justifying-space (sometimes called a 'spaceband' rather than 'justifying >>>> space'). Use of the quad-space within justified text would force the >> fixed >>>> nominal-width of the normal interword space character, disabling >>>> justification adjustments. This encoding concept has no analogy in >> Unicode. >>>> All other space characters {EM-space, EN, EM-quad, EN-quad, 3/EM, 4/EM, >>>> 6/EM, Thin, & Hair} are treated as fixed width and are not adjusted for >>>> letterspacing nor for wordspacing. (Traditional publishing systems used >>>> these for alignment/layout and did not generally apply tracking nor >> WSA/WSR >>>> either.) >>>> >>>> Ideographic languages/scripts do not generally use wordspacing or >>>> letterspacing to adjust justification; instead they typically use >> rules akin >>>> to those described in JIS-4051 (latest). This algorithm involves >> trimming >>>> some characters to half-width, then reinserting 1/2 & 1/4-em spacing >>>> adjustments at selected points within the line. >>>> Under these rules, Ideographic-space is treated as an ideographic letter >>>> [generally fixed-fullwidth, but has some specific additional rules], >> and not >>>> as a roman variable space. >>>> It should be a styling option of whether Roman text embedded in >>>> Ideographic text is set using Roman algorithms or Japanese/Chinese >>>> algorithms. Depending on the publication and the publisher, Roman >> text may >>>> be set proportional (using Roman or Asian justification rules), >> halfwidth, >>>> or fullwidth. (Similarly, they may choose Asian or Roman >> word-breaking and >>>> hyphenation rules.) >>>> >>>> I have not covered any specifics in the handling of ancient >> languages that >>>> are generally only of academic interest; nor the handling of Arabic and >>>> Arabic-dervative scripts; nor Indic; nor certain other language-specific >>>> differences (such as adjustments to spaces on sentence boundaries in >> some >>>> uses , nor after certain punctuation characters in French and other >>>> languages). >>>> >>>> I have also not addressed the handling of "hanging punctuation" and >> "hanging >>>> spaces"; though there are different philosophies/algorithm for handling >>>> these across the various script families. >>>> >>>> -- S.Deach >>>> sdeach@adobe.com >>>> >>>> >>>> >>>> >>>> >>>> >>>> On 2008.10.31 02:43, "Martin Duerst" <duerst@it.aoyama.ac.jp> wrote: >>>> >>>> >>>>> Hello everybody, >>>>> >>>>> Just a bit of a wider background on full-width space. >>>>> >>>>> It should be remembered that in contrast to the usual space (U+0020), >>>>> which occurs all over the place in texts in most languages, the >>>>> full-width space doesn't occur AT ALL in typical Japanese (or Chinese) >>>>> texts. That's why it also barely occurs in the document written >>>>> by the Japanese Layout TF, as well as in JIS 4501. >>>>> >>>>> The full-width space is more used for layout than inside the actual >>>>> text. In this respect, what CSS should do is to mainly look at >>>>> Japanese typography and try to come up with properties that allow >>>>> to get rid of full-width spaces in the text, rather than spending >>>>> too much time on how to treat full-width space. >>>>> >>>>> As a typical example, I guess lead typesetting and also definitely >>>>> simple approaches to typesetting on the computer, such as plain >>>>> text or old "word-processors" (which were not very much above >>>>> plain text in their capabilities) use a full-width space to produce >>>>> a start-of-paragraph indent (which is very often one full-width >>>>> character wide). CSS should make sure that there is no need to >>>>> insert such full-width spaces, because an exact one-full-width- >>>>> character start-of-paragraph indent can be produced with an >>>>> appropriate CSS property setting. >>>>> >>>>> Another typical use of full-width space was to center text, >>>>> and to insert spaces into text for headlines (to a large >>>>> extent a crude backup for increasing text size, which wasn't >>>>> possible when technology was limited to one or two bit-mapped >>>>> font sizes. In this case, inter-character spacing property(/ies) >>>>> may be important for 'facsimile' layouts, but with modern >>>>> technology, such layout isn't much used anymore anyway. >>>>> >>>>> Regards, Martin. >>>>> >>>>> At 18:31 08/10/30, KOBAYASHI Tatsuo(FAMILY Given) wrote: >>>>> >>>>>> Hi, Erica, >>>>>> >>>>>> In Japanese Layout, "spacing issue" is one of the most difficult >> issues to >>>>>> treat. >>>>>> We intended to carefully eliminate concrete character name like >> IDEOGRAPHIC >>>>>> SPACE(U+3000) and SPACE(U+0002) from our requirement. Rather >> introduced >>>>>> three >>>>>> different types of abstract space concepts as follows: >>>>>> >>>>>> inter character space: usulal 1/2 em fixed space. >>>>>> conditional space: 1/2 em fixed space to be inserted or pulled off >> between >>>>>> characters and punctuation marks. >>>>>> adjustable space: variable width space, behaves like usual western >> variable >>>>>> space. >>>>>> >>>>>> Note that, usual Japanese punctuation marks have 1/2 em width in our >>>>>> requirement, even if the character name might include "FULLWIDTH ~~~" >>>>>> >>>>>> Anyway, the disition how to deal with these spaces in CSS >> recommendation >>>>>> and >>>>>> in actual implementation is up to your side:-) >>>>>> >>>>>> regards, >>>>>> Tatsuo >>>>>> >>>>>> 2008/10/30 Steve Deach <<mailto:sdeach@adobe.com>sdeach@adobe.com >> <mailto:sdeach@adobe.com%3Esdeach@adobe.com>> >>>>>> >>>>>>> No, in my personal opinion, it should not. >>>>>>> The 2 differences between normal space/nbsp vs ideographic space are: >>>>>>> 1.) The normal width is different, and >>>>>>> 2.) The normal space/nbsp is treated as justifying >>>>>>> (adjusted by both wordspacing and letterspacing), >>>>>>> whereas the Ideographic space should only be adjusted by >>>>>>> letterspacing (only if ideographic letters are also so adjusted). >>>>>>> >>>>>>> However, I will re-confirm this with our CJK experts, before >> claiming this >>>>>>> is an Adobe opinion. >>>>>>> >>>>>>> >>>>>>> >>>>>>> On 2008.10.29 15:13, "fantasai" >>>>>>> >> <<mailto:fantasai.lists@inkedblade.net>fantasai.lists@inkedblade.net >> <mailto:fantasai.lists@inkedblade.net%3Efantasai.lists@inkedblade.net>> >>>>>>> wrote: >>>>>>> >>>>>>> >>>>>>>> Hello, >>>>>>>> >>>>>>>> The CSSWG would like to know whether the IDEOGRAPHIC SPACE U+3000 >>>>>>>> should be affected by 'word-spacing', and whether it should be >>>>>>>> treated as a space during spaces-only justification or treated as >>>>>>>> a typical ideographic punctuation character. >>>>>>>> >>>>>>>> ~fantasai >>>>>>>> >>>>>>>> >>>>>>> >>>>>> >>>>>> -- >>>>>> KOBAYASHI Tatsuo >>>>>> Scholex Co., Ltd. Yokohama >>>>>> JUSTSYSTEM Digital Culture Research Center >>>>>> >>>>> #-#-# Martin J. Du"rst, Assoc. Professor, Aoyama Gakuin University >>>>> #-#-# http://www.sw.it.aoyama.ac.jp mailto:duerst@it.aoyama.ac.jp >>>>> >>>>> >>>> >>>> >>>> >>>> >>>> >>> >
Received on Friday, 31 October 2008 22:02:49 UTC