[Devel] FT_Set_Hint_Flags() , etc.

[David Chester]

Is the implementation of adding configurable options to the hinters still
a work in progress?  It looks like its 99% done, but the hinters aren't
reading the information from face->internal->hint_flags.

Shouldn't there be lines like:

hinter->no_horz_hints = \ 
          hinter->face->internal->hint_flags & FT_HINT_NO_HSTEM_ALIGN;

hinter->no_vert_hints = \
          hinter->face->internal->hint_flags & FT_HINT_NO_VSTEM_ALIGN;

in ahhint.c, and similar lines in the postscript hinter?

And why is there only one flag (FT_HINT_NO_INTEGER_STEM) for stem
snapping?  Since it seems that there are options in both the pshinter and
the autohinter to independently toggle the snapping of vertical and
horizontal stems, why not have two seperate flags,
FT_HINT_NO_INTEGER_HSTEM and FT_HINT_NO_INTEGER_VSTEM?

When I've made the above changes, FT_Set_Hint_Flags() works as I would
expect, and to my eyes, the results are fairly promising.

Still, though, serif fonts still seem to suffer quite a bit of distortion
even with only the hstem alignment (no snapping, no vstem alignment).  I
wish there were another hinting option where only the extreme top and
extreme bottom of the outline would be aligned on a pixel boundry, and
the rest would be left to fall where it might.

Here's an example which shows Times New Roman very slightly hinted,
similar to how I've just described, but with a few shortcomings.  

http://www.cs.mcgill.ca/~dchest/salon1.png

The implementation in the example is lacking in that the e's and s's,
etc. reach a tiny bit into the pixel row below, and the f's and p's and
q's are left alone, unstretched, so their stems are fuzzy.  But, it's
sort of close.  There's also some gamma correction on the TNR.  In case
anyone's wondering, the Verdana is hinted with the new options: vstem
alignment and vstem snapping are turned off.  Also, with both fonts, I've
altered FT_Set_Char_Size() so that it doesn't round my supplied
char_width and char_height, and I can choose more strategic values. 

Thoughts, comments?

Regards,
David Chester

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