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Re: CSS Text 3 Comments

From: Brady Duga <duga@google.com>
Date: Thu, 7 Nov 2013 09:38:38 -0800
Message-ID: <CAH_p_eUHQXa_iC=kGSEPbsTrCYR52Jm_pcXZxZUPXKXCHGT0eA@mail.gmail.com>
To: Markus Gylling <markus.gylling@gmail.com>
Cc: W3C Public Digital Publishing IG Mailing List <public-digipub-ig-comment@w3.org>, W3C Digital Publishing IG <public-digipub-ig@w3.org>
Looks good, though I just noticed there are 2 number 19s. Might want to
promote one before you send this on.


On Thu, Nov 7, 2013 at 4:59 AM, Markus Gylling <markus.gylling@gmail.com>wrote:

> Hi all,
> thanks for your work on this. Below is a list that intends to compile your
> comments, starting with the list Brady provided, and comments from Dave,
> Eric, Jean et. al. inserted in natural order. I have left out the
> discussion on positional pseudo-elements, as there seemed to be agreement
> that this is not LC-level stuff (but this proposition could/should of
> course be forwarded to the CSS WG via other channels).
>
> I’ll let this sit until noon PST awaiting any final comments you might
> have (did I miss something? more non-LC stuff included that we want to save
> for later? etc) and then send our reply to Bert.
>
> Again, thanks! /markus
>
> --- begin ---
> 1. It would be great to keep the ‘hanging-punctuation’ property, though I
> understand it is awaiting implementations. What is the timeline here? That
> is, when would an implementation need to appear in order to preserve this
> property?
>
> This is certainly important to us. Antenna House has implemented this, and
> it's on the roadmap for Prince.
>
> 2. In section 1.3, after the example:
> "Within this specification, the ambiguous term character is used as a
> friendlier synonym for grapheme cluster. See Characters and Properties for
> how to determine the Unicode properties of a character."
> "A letter for the purpose of this specification is a character belonging
> to one of the Letter or Number general categories in Unicode. [UAX44]"
> If I replace 'character' in the second paragraph with 'grapheme cluster',
> I am not sure I get a reasonable answer. For instance, is U+0067  + U+0308
> a letter? I don't think U+0308 is, does that disqualify the whole cluster?
> Or is this a different use of the term character? Does Unicode define such
> clusters as belonging to all the groups all the code points belong to?
>
> 3. The only place the spec mentions that text-transform should affect line
> breaking is in an informative example (#2), at least that I saw. Should
> this be mentioned in a normative section? Some line breaking changes are
> obvious (for instance, changing the width of the glyphs will alter line
> breaking), but others are more obscure (for instance, transformation to
> full width).
>
> 4. From 5.1, last bullet point:
> "For line breaking in/around ruby, the base text is considered part of the
> same inline formatting context as its surrouding content, but the ruby text
> is not: i.e. line breaking opportunities between the ruby element and its
> surrounding content are determined as if the ruby base were inline and the
> ruby text were not there." [Also, note the typo: surrouding]
> The first part of this sounds like breaks are allowed in a single run of
> base text (difficult, I assume), but the second part sounds like breaks are
> only allowed at boundaries of the ruby element. It seems like, in practice,
> breaks are allowed anywhere in a ruby element a break would be allowed if
> such a location is also a base text boundary.
> For example, consider this snippet:
> <p>だ<ruby>大分<rt>だいぶ</rt>日数<rt>ひかず</rt></ruby>が</p>
> From "the base text is considered part of the same inline formatting
> context as its surrouding content, but the ruby text is not", I might
> imagine breaks as though the text were written
> だ[1]大[2]分[3]日[4]数[5]が
> But, this: "i.e. line breaking opportunities between the ruby element and
> its surrounding content" seems to imply this only covers line breaks at the
> boundary of the ruby element itself. In which case I would get:
> だ[1]大分日数[5]が
> However, I would expect the correct breaking would be neither of those,
> but rather:
> だ[1]大分[3]日数[5]が
> I am not certain how I can interpret the spec to generate those line
> breaks.
>
> 5. In "5.2. Breaking Rules for Punctuation", in this sentence and the one
> below it that is similar:
> "If the content language is Chinese or Japanese, then additionally allow
> (but otherwise forbid) for ‘normal’ and ‘loose’:"
> It's not clear to me what the 'otherwise' applies to - is it the 'normal'
> and 'loose', so it is forbidden in strict when the language is Chinese or
> Japanese? Or does it apply to the language as well, so it is forbidden in
> strict for Chinese and Japanese, and for any value for all other languages?
> If the latter, then the implication is that in eg English, breaks before
>  U+2010 are forbidden. However, the later clarifying note seems to indicate
> that non-CJK text is only affected when the language is Chinese or Japanese.
>
> 6. In "6.1. Hyphenation Control", the sentence: "The UA is therefore only
> required to automatically hyphenate text for which [...]"
> Is it the case that a UA is ever *required* to automatically hyphenate?
> Perhaps this should be weakened to "Therefore, if no language is specified
> or no hyphenation resource is available to the UA for a specified language,
> the UA may choose to treat 'auto' as 'manual'."
>
> Section 6.1 also states, "Conditional hyphenation characters inside a
> word, if present, take priority over automatic resources when determining
> hyphenation opportunities within the word." Is this a strong-enough
> statement? We've seen many cases where a word will hyphenate one character
> away from a soft hyphen.
>
> 6.1 In example 8, there is an extra nun in نوشتنن, at the end. I think it
> should be نوشتن.
>
> 7. Not really wrong, but the order of property names in the title for 6.2
> is the opposite of the order just below, in the definition,
> ‘word-wrap’/‘overflow-wrap’ vs overflow-wrap/word-wrap. Just a little weird.
>
> 8. "6.2. Overflow Wrapping", so sayeth Yoda:
> "[...] and grapheme clusters must together stay as one unit." Maybe "stay
> together" instead?
>
> 9. In "7.1. Text Alignment", "text-align: start end" sounds a lot like
> "text-align-last: *", giving special treatment to the first line instead of
> the last line, with less control. Perhaps there should be a separate
> property for controlling the first line alignment, just like there is for
> controlling the last line. Then text-align could become a shorthand. For
> example:
>
> text-align: center == text-align-first: center, text-align-middle: center,
> text-align-last: auto
> text-align: center right == text-align-first: center, text-align-middle:
> center, text-align-last: right
> text-align: left center right == text-align-first: left,
> text-align-middle: center, text-align-last: right
>
> This makes the proposed 'text-align: start end' become 'text-align: start
> end end' instead.
> Of course, the down side is this would require two new properties
> ("text-align-first", "text-align-middle"). Not sure if this is worth
> considering at this point, but it seems odd to handle this in different
> ways for different special lines. Perhaps drop 'start end' for now and
> reconsider for level 2?
>
> Sometimes we need to force a line-break inside a paragraph for various
> reasons
> [novelists-sometimes-string-together-dozens-of-words-with-hyphens-leaving-no-natural-break-points].
>  Having text-align-last control this is almost never what we want. In the
> most common case, we want the last line left-aligned and all other lines
> justified, as in most books published in the last five hundred years.
> Separating text-align-middle from text-align-last would be very helpful.
>
> 10. What impact do zero-width letters and zero-width word-separators have
> on the inter-word and distribute text-justify values?
>
> 11. I take exception to example 10 in 7.3.5. Both the greedy algorithm and
> the Knuth/Plass algorithm are O(n). What performance metrics are you using
> to determine the relative speed of these algorithms? Additionally,
> Knuth/Plass is easily adapted to other languages, so it applies equally to
> example 11. Perhaps "harder to implement" instead?
>
> 12. "8.1. Word Spacing": Can this property be used to make words overlap?
> That is, are values less than -100% allowed? 'letter-spacing' says there
> may be UA limitations for such things.
>
> 13. letter-spacing says it doesn't apply at the start/end of a line.
> Should there be similar text be in word-spacing?
>
> 14. At the end of word-spacing (just after example 13), the text
> "Word-separator characters include [...]" - is this considered an
> exhaustive list? If so, this should be made clear, otherwise some sort of
> guidelines for deciding what else might be a word-separator would be useful.
>
> 15. In "8.2. Tracking", just after example 14: "[...] to the innermost
> element element that contains the two characters [...]"
> Just one element?
>
> 16. And just after example 15: "Letter-spacing ignores zero-width
> characters (such as those from the Unicode Cf category)." Does this mean
> characters that are defined to be zero-width, or characters whose width
> might be zero? For instance, given:
>
> span.zero { display: inline-block; width: 0; }
> p {letter-spacing: 1em;}
>
> <p>a<span class="zero">b</span>c</p>
>
> Would this be viewed as "a bc" (1em after 'a', zero-width 'b', 1em after
> end of 'b', 'c') or as 'a' with 'b' and 'c' on top of each other 1em later?
>
> We are disappointed that maximum and minimum values for word-spacing and
> letter-spacing were removed in this draft. Better control over
> justification is a key requirement for us.
>
> 17. In "9.1. First Line Indentation", it is not clear to me what
> 'each-line' is doing. Does this simply make the indent of lines after hard
> line breaks indent, and they wouldn't otherwise? If so, perhaps it should
> say "In addition to the first line of a block container each line after a
> forced line break are also affected. Lines after a soft wrap break are
> still not affected." Or maybe there is something else going on I just don't
> understand.
>
> I found this section a bit confusing. Perhaps examples of "hanging" and
> "each-line" would be helpful.
>
> 18. In "9.2. Hanging Punctuation", the 'Animatable:' table entry has a
> spurious gt ('>').
>
> 19. Appendix A, steps 5.iv and 5.v - how do you do letter and word spacing
> without knowing the font in use? For instance, a percent value for letter
> spacing depends on the advance measure of the character, which will depend
> on the current font.
>
> 19. Appendix B:
> "[...]  is to help UA developers to implement default stylesheet [...]" -
> 'a default stylesheet'? Or maybe 'the default stylesheet'? Or even 'default
> stylesheets'?
>
> --- end ---
>
> On 05 Nov 2013, at 17:55, Cramer, Dave <Dave.Cramer@hbgusa.com> wrote:
>
>   On 11/5/13 11:25 AM, "Brady Duga" <duga@google.com> wrote:
>
>   I was also thinking about different margins based on page-facing. Do we
> need to target new, left and right pages? Or even/odd pages? Seems like
> this is a complex enough discussion to avoid in LC comments.
>
>
>  PrinceXML uses margin-inside and margin-outside. There's been some talk
> in the CSS WG about allowing element styling based on @page context (:left,
> :right, :first).
>
>  So much of layout involves position—it's OK to hyphenate a word, except
> when it's the last word on a left-hand page. I sometimes feel that our
> biggest problem isn't that CSS is missing some features, it's that CSS
> doesn't allow us to target the situations we want to change. The first page
> of a chapter, the last word on the page, the second star to the right…
>
>  Dave
>
>
>
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Received on Thursday, 7 November 2013 17:39:06 UTC

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