UTR #50 Review Memo
This page is a memo page to make our discussion on UTR #50 smooth.
Analysis by Codepoint
Two modes are presented: Stacked (
text-orientation: upright) and Mixed (
text-orientation: mixed). Codes used for analysis by codepoint:
|U||Upright; translates between horizontal and vertical
|R||Sideways; rotates between horizontal and vertical
|TU||Typeset upright with alternate glyph. Best fallback is just upright.
|TR||Typeset upright with alternate glyph. Best fallback is just sideways.
|V||Upright wrt Unicode code charts, but translates between horizontal and vertical (VO=U/HO=L)
Codepoint classifications and notes by general category:
Potential tailoring categories:
Notes on Interaction with Font Design
From what I understand, T allows anything; from changing glyph to changing orientations, so although “representative glyphs” are shown, their orientations are undefined in UTR #50. Some rotate, some do not, and it's up to font designer. Is this correct understanding?
If UTR #50 means fonts should not change glyphs/positions for U/S/SB, there are compatibility and font designing problems here.
Issues with non-square fonts:
U does not work with proportional or non-square fonts. If a font is condensed (tall) in horizontal flow, it needs to be condensed (wide) in vertical flow; e.g., AXIS fonts
S/SB does not work with slanted fonts; e.g., susha.png
Does the baseline alignment work good by just rotation?
EM DASH, Arrows, etc. aligns at center baseline?
Most font designers I contacted believe that it's ok as long as the font is a square font, but I'm worried as it has never been tested at all.