Vertical Layouts for Canvas Text (CJK)

I have noticed a discussion (I have cut some parts for readability) about vertical layout for text from the participants of the HTML WG.

<Hixie> ok for canvas text my proposal is:

<Hixie> drawHString(x, y, maxWidth, textAlign, s); and drawHString(x, y, maxHeight, textAlign, s);

<Hixie> drawVString(...) for the second one

<Lachy> what's the difference between them? drawVString for vertical stings where the letters are stacked on top of each other, and not just rotated 90 deg?

<Philip`> Hixie: They look complex and hard to use :-p

<Philip`> compared to e.g. translate(x,y);drawString(s)

<Hixie> lachy: drawVString() would be for vertical text (e.g. some CJK)

<Hixie> one is lack of support for vertical text :-)

In printed media, it is handled quite well for a long time. Japanese books have some complex layouts mixing western and japanese characters.

It happens not only in CJK (Chinese Japanese Korean) texts. Think about a neon sign of an hotel with the letters written vertically.

Felix Sasaki is my colleague at W3C/Keio and has worked with the Japanese Layout Task Force. He was sitting next to me when I was reading the logs of the discussion, so I just asked him some references. He sent me a link to 1.3 Directional Factors in Japanese Text Layout from the Requirements of Japanese Text Layout. He also reminded me about XSL 1.1: 7.29.3 "glyph-orientation-vertical" .

Wikipedia has a page on the topic of Horizontal and vertical writing in East Asian scripts and Unicode a note on Robust Vertical Text Layout.

All of that should help to define the API for Canvas Text.