Re: [ft] Vertical font layout

[mpsuzuki]

Sorry for lated post.

On Wed, 22 Mar 2006 06:19:34 UT
Paresh Deshmukh <address@hidden> wrote:
>I am having one more query. MsMincho.ttc support vertical layout,
>what will be the expected output for zero degree oriented and
>single byte text with
>FT_Load_Glyph(face, Glyph_Index, FT_LOAD_VERTICAL_LAYOUT).
>I checked with MsWord Vetical box for double byte 'A' it
>print correclty but for single byte it prints rotated 'A'.
>Is there any relation between verival layout and mulibyte char.

I understand as: when you use 16bit ASCII ("Full-Width ASCII"
in Unicode terminology), you get what you expected. But when
you use 7bit ASCII (genuine US-ASCII), you could not get what
you expected - although MS Word shows the text aligned vertically,
all glyphs lie sideways. If I'm misunderstanding, please
discard following and correct me.

According to Apple's TrueType specification:
        http://developer.apple.com/fonts/TTRefMan/RM06/Chap6bdat.html
(I found same information in "EBLC" table description in 
 Microsoft's TrueType specification, ttch02.doc, page 21),
I can say, the result you see in 7bit US-ASCII is NOT
layouted by vertical metrics.

I have to say, MS Word (and either MS Wordpad.exe) is too
complicated to check the behaviour of vanilla TrueType text
layout: its vertical layout is not only by vanilla TrueType,
there are various extra empirical / implicit rules designed
for CJK market. Such extra rules is not always "reasonable"
for ASCII/Latin-1 scripts. The result you see in 7bit US-ASCII
is "prefered style" for 7bit US-ASCII in vertical writing mode
for CJK script. Don't take it as exact behaviour of TrueType
text layout.

Regards,
mpsuzuki