[csswg-drafts] [css-text-4] text-spacing, "3/4-width" in fullwidth punctuation collapsing

MurakamiShinyu has just created a new issue for https://github.com/w3c/csswg-drafts:

== [css-text-4] text-spacing, "3/4-width" in fullwidth punctuation collapsing ==
https://drafts.csswg.org/css-text-4/#fullwidth-collapsing

> - Set fullwidth opening punctuation half-width if the previous character is a fullwidth opening punctuation, fullwidth middle dot punctuation, or ideographic space (U+3000). Else set it full-width.
> - Set fullwidth closing punctuation half-width if the next character is a fullwidth closing punctuation, fullwidth middle dot punctuation, or ideographic space (U+3000). Else set it full-width.
> - Set fullwidth closing punctuation followed by fullwidth opening punctuation each at "3/4-width", i.e. halfway between full-width and half-width.

I think the last item above, "3/4-width" rule, is not necessary and the first item should be changed to:

> * Set fullwidth opening punctuation half-width if the previous character is a fullwidth opening punctuation, fullwidth middle dot punctuation, fullwidth closing punctuation, or ideographic space (U+3000). Else set it full-width.

The reasons are as follows:
-  as mentioned in https://github.com/w3c/csswg-drafts/issues/535#issuecomment-251880316, it is not appropriate when we use half-width / full-width glyphs.
- According to JIS X 4051, Table 5, the half-width space between the closing punctuation and the opening punctuation is attached to the former (closing) punctuation. i.e., the closing punctuation should be set full-width and the opening punctuation should be set half-width. (This is unclear in JLREQ but is clear in JIS)
-  Existing typesetting software such as InDesign support the above JIS X 4051 rule.


Example 9 table (Demonstration of adjacent-pairs punctuation trimming) should also be changed:

> Closing—Opening   〕+（  )  (

to

> Closing—Opening   〕+（  〕(

BTW, the current stylesheet in css-text-4 cannot render well this table. I found the css-text-3 stylesheet has the following style:

```css
    .char { border: 1px dotted gray; }
    .quarter { font-size: 25%; }
    tt[lang="ja"] { font-family: "MS Gothic", "Osaka", monospace }
```

I think this should be moved to css-text-4 stylesheet, with some fixing:

```css
    .char { border: 1px dotted gray; }
    .quarter { font-size: 25%; }
    samp[lang="ja"] { font-family: "MS Gothic", "Osaka-Mono", monospace }
```

Note that regular "Osaka" font is not appropriate because its fullwidth punctuations are not really full width (very narrow!) in current macOS font environment. So I think "Osaka-Mono" is better.



Please view or discuss this issue at https://github.com/w3c/csswg-drafts/issues/1668 using your GitHub account

Received on Tuesday, 1 August 2017 07:02:52 UTC