[HarfBuzz] Question about shaping with top to bottom direction

[Simon Cozens]

On 16/07/2015 16:21, aronsoyol wrote:
> When shaping it with top to bottom direction and paint it. As you
> see the orientation of number "2015"'s glyph is not expected. they
> should be rotated 90 degrees

Actually I would expect exactly what you got, although it would look
better if you had used the Japanese full-width numberic glyphs (２０１５).

There are multiple ways to arrange Latin text within Japanese vertical
texts; rotating the glyphs is one way, another way is to use fixed-width
full-width characters in horizontal orientation, and tate-chu-yoko is
another one. See http://www.w3.org/TR/jlreq/#fig1_19-en

Because there are multiple ways to do this, Harfbuzz isn't going to
choose between them for you. You have to do that. And Japanese fonts
generally don't contain rotated forms of Latin glyphs, whereas
Harfbuzz's job is just to go from Unicode text to the glyphs that are in
your font, so it can't really help you in this case. If you want to
rotate the Latin text, you need to do it yourself.

Simon