This is the file vertical.txt of the CJK macro package ver. 4.8.5
(16-Oct-2021).


Vertical typesetting
====================

TeX itself can't support vertical typesetting. Nevertheless, it is possible
to emulate it by rotating glyphs by 90 degrees.

The CJK package supports two different approaches:

o   Provide fonts which already contain rotated glyphs. In this case, the
    only difference to normal typesetting is the emulation of bold
    characters by printing a character three times with slight vertical
    offsets instead of horizontal ones. Both hbf2gf and ttf2pk can produce
    rotated bitmap fonts. The major disadvantage is that it doesn't work
    well for outline fonts since there is no portable way to implement
    rotation on the font level which works for both PostScript and PDF
    output.

    You need a `.fdx' file for this option which at least contains
    `\CJKvdef{norotate}{}'.

o   Use the graphicx package to rotate glyphs. A disadvantage is that
    processing of a document is much slower and that documents tend to be
    much larger in size. On the other hand, PDF and PostScript output can be
    produced from identical sources since graphicx hides the implementation
    differences.

    This works even without a `.fdx' file in case CJK's default rotation
    parameters are fine.


CJKvert.sty
-----------

Loading CJKvert.sty activates vertical support. The two commands to be used
in documents are \CJKvert and \CJKhorz which do the obvious. \CJKvert is
the default. The two commands act locally, not globally.

Use macro \CJKbaselinestretch to adjust the baseline stretch during vertical
typesetting. The default value is `1.3'.

Package option `usebaselinestretch' saves the \baselinestretch value set
before loading CJKvert.sty. If this option is active, then

  new \baselinestretch = \CJKbaselinestretch * \baselinestretch

after issuing \CJKvert. Otherwise, it is simply

  new \baselinestretch = \CJKbaselinestretch

Similarly, \CJKhorz restores the old \baselinestretch value if
`usebaselinestretch' is active; without the option, \baselinestretch is set
to `1'.


Problems with vertical typesetting
----------------------------------

Some glyphs can't be used directly for vertical typesetting; a simple
rotation by 90 degrees would produce ugly results for various reasons:

o   Many punctuation characters have special vertical representation forms.
    Some fonts contain proper vertical glyphs, but many don't. In the latter
    case it is necessary to provide alternative methods to improve the
    optical appearance.

o   Non-rotated (latin) text within rotated (CJK) text is aligned
    differently as if text is written horizontally. Rotated glyphs thus must
    be slightly shifted.

o   Some fonts contain CJK glyphs without quadratic bounding boxes but only
    monospaced advance widths. It is then necessary to provide glyph
    dimensions to assure monospaced advance heights after rotation.

See the documentation file `fdxfiles.txt' for details on setting up
extended font definition files which can handle those items.


Fonts with vertical representation forms
----------------------------------------

OpenType fonts intended for vertical typesetting normally contain a GSUB
feature called `vert' which provides a mapping to vertical instead of
horizontal representation forms. ttf2tfm automatically takes care of it (see
below), but if such fonts have been converted to sets of Type 1 subfonts
this feature is lost.

A solution to this problem is to collect all vertical representation glyphs
in a special Type 1 subfont. See the scripts vertical.pe, vertref.pe (for
FontForge), and makefdx.pl (for Perl) in the directory utils/subfonts which
do that.

At the moment of this writing, only the fonts bsmi00lp.ttf and bkai00mp.ttf
for traditional Chinese have been transformed to Type 1 subfonts together
with a font with vertical representation glyphs (bsmilpv.pfb and
bkaimpv.pfb). They are part of the corresponding CJK font bundles found on
CTAN. See the file INSTALL for more information.


Rotated fonts
-------------

o   To install a rotated font to be handled by hbf2gf, simply proceed as
    usual, with one difference: You have to add a line

        rotation  yes

    to the hbf2gf configuration file of this font. x_offset and y_offset
    values must be adjusted too. Look at the example configuration file
    b5kr12.cfg for details---as you can see, the name of the non-rotated
    font (b5ka12) has been changed to `b5kr12'.

o   With ttf2tfm, use the `-x' switch to activate rotation. For details
    please refer to the man pages of ttf2tfm and ttf2pk.


---End of vertical.txt---