[HarfBuzz] GSUB for vertical layouts (CJK)

[Behdad Esfahbod]

On 05/31/11 09:08, Grigori Goronzy wrote:
> Another font I tested that normally is available in a single file per
> font, Matisse Pro, doesn't show any such irregularities and everything
> looks great--positioning and substitutions. Enabling `vrt2' makes it use
> vertical only for CJK characters. Very nice!

So, here is my current plan, based on a quick reading of the OpenType feature
registry:

  * vrt2 should be enabled if available, otherwise vert is enabled.
    Note: If user explicitly asks for vert, then vrt2 should not be enalbed.

  * vkrn is enabled.  vpal enabled if vkrn is enabled.
    Note: I have no idea if anyone even uses vpal.

  * valt is enabled?  The docs say some nonsensical stuff.


behdad