[ft-devel] `gasp' table version 1 and update to `head'

[Werner LEMBERG]

Greg Hitchcock from MS provided some information regarding the gasp
table format, version 1.  I'm only listing the differences.

  field               description

  version              1
  rangeGaspBehavior    bit 3: GASP_SYMMETRIC_SMOOTHING
                         Use smoothing along multiple axis with
                         ClearType.
                       bit 4: GASP_SYMMETRIC_SMOOTHING
                         Use gridfitting with ClearType symmetric
                         smoothing.

                       Bits 0 and 1 (GASP_DOGRAY and GASP_GRIDFIT)
                       operate independently of bits 2 and 3.  If font
                       smoothing is enabled, then the first two bit
                       flags are used.  If ClearType is enabled, then
                       the following two bit flags are used.


The version number has been increased to avoid tri-states of the bits
(set, unset, and undefined) due to the introduction of the parallel
interpretation of `rangeGaspBehavior' (this is, with and without
ClearType).


Additionally, bit 13 in the `flags' field of the `head' table got a
meaning:

  Font optimized for ClearType.  If this flag is cleared, East Asian
  fonts in the Windows Presentation Framework (formerly known as
  `Avalon') will not be hinted.  Setting this flag will enable
  hinting.


    Werner