Line spacing/line height when mixing Chinese and Western text

[xfq]

Should we mention in CLReq what the requirements are for line spacing when mixing Chinese and Western text?

Additionally, when mixing Chinese characters with complex scripts like Thai or Javanese, a greater line height may be required.

我们是否需要在CLReq里提一下中西文混排时对行距有什么要求？

另外，当汉字与泰文、爪哇字母的复杂文种混排时，需要的行高可能会更高。

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泰文：

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爪哇字母：

[macnmm]

I would recommend considering a hierarchical approach. The dominant language system should dictate the metrics and line height for all lines in the paragraph; the subordinate script systems are then aligned (and/or scaled) to align and place text within that height and relative to those metrics.
For example, CJK dominant lines are the height of the ideographic embox of the largest font run; all other scripts align their baseline/origin to an appropriate offset into that height.
It is often more important to have a consistent line height in a mixed script paragraph, which may cause line collisions of the ink; in other instances individual lines are adjusted to avoid this. Therefore it is best to offer a choice of behaviors.