Re: [jlreq] Example of central-baseline alignment of sideways-ed Latin glyphs within a vertical Japanese line box (#246)

http://www.gtalbot.org/BugzillaSection/Bug1673499-Mixed-fonts-line-height-v7.html

Each font can (preferably should) have a baseline table so that glyphs in a mixed script scenario can be positioned according to the dominant baseline. The dominant baseline for 'writing-mode: vertical-rl' is center (assuming 'text-orientation' is 'mixed'). So, rotated sideways 90° clockwise Latin glyphs must use the central baseline, must be centrally-baseline aligned within the line box. The demo 
Bug1673499-Mixed-fonts-line-height-v7.html demonstrates this, with both Firefox 78.5.0 ESR and Chrome 83.0.4103.116 succeeding with 3 available fonts (M+ 1p, Noto Sans CJK JP Regular, Noto Sans CJK SC Regular) in the code (you can toggle On/Off any of the 3 font faces in Web Inspector tool).


{
It is not true that the Latin glyphs are centrally aligned in vertical -- they ride on their own Latin baseline that is placed at an appropriate point (derived e.g. by centering the cap height) inside the cjk embox. If there were mixed sizes, I would expect the Latin baseline to be common and those glyphs align to it (e.g. be rotated and left-aligned to their Latin baseline), rather than have them centered on their cap heights
}

If I understand you correctly (and I think I do), then this is not what Firefox and Chrome do and this is not what the CSS spec states (although not very clearly, I admit).

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Received on Friday, 4 December 2020 04:14:56 UTC