Use U+22EF MIDLINE HORIZONTAL ELLIPSIS for ellipses?

[xfq]

Chapter 6.2, pages 276-277 of v14 of the Unicode Standard suggests using ⋯ U+22EF MIDLINE HORIZONTAL ELLIPSIS instead of … U+2026 HORIZONTAL ELLIPSIS for CJK:

In East Asian typographic traditions, particularly in Japan, an ellipsis is raised to the center line of text. When an ellipsis is represented by U+2026 HORIZONTAL ELLIPSIS or by sequences of full stops, this effect requires specialized rendering support. In practice, it is relatively common for authors of East Asian text to substitute U+22EF MIDLINE HORIZONTAL ELLIPSIS for this. Because the midline ellipsis is a mathematical symbol, intended to represent column elision in matrix notation, it is typically used with layout on a mathematical center line. With appropriate font design to harmonize with East Asian typography, this midline ellipsis can produce the desired appearance without having to support contextual shifting of the baseline for U+2026 HORIZONTAL ELLIPSIS.

U+22EE VERTICAL ELLIPSIS and U+22EF MIDLINE HORIZONTAL ELLIPSIS are part of a set of special ellipsis characters used for row or column elision in matrix notation. Although their primary use is for a mathematical context, U+22EF MIDLINE HORIZONTAL ELLIPSIS has also become popular for the midline ellipsis in East Asian typography. When U+22EF is used this way, an East Asian font will typically contain a rotated glyph variant for use in vertical text layout. If an appropriate mechanism for glyph variant substitution (such as the “vert” GSUB feature in the Open Font Format) in vertically rendered text is not available, U+FE19 presentation form for vertical horizontal ellipsis is the preferred character substitution to represent a vertical ellipsis, instead of the mathematical U+22EE VERTICAL ELLIPSIS.

Should we consider recommending the use of the midline ellipsis?

[xfq]

Relevant section in clreq: https://w3c.github.io/clreq/#id83

[bobbytung]

It's all about capability. Android system, before / around version 4.0, the system font Droid did not contain U+22EF MIDLINE HORIZONTAL ELLIPSIS and the system cannot display this code point even with web font or embedded font.

Now, if new Android system fixed this issue and system font contains this glyph. We should list this code point in CLREQ as well.

[bobbytung]

追加備註：

在Unicode標準第14版的6.2章中，亦推薦使用U+22EF MIDLINE HORIZONTAL ELLIPSIS作為刪節號。

此符號配合適當的轉向與取代機制，在顯示上無論直橫排，刪節點皆居中，更符合排版需求。然而，在Unicode編碼中歸類於數學符號，在一些早期的作業系統，可能無法顯示。