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Re: [ft-devel] [GSoC] CID font support, and others

From: Dave Arnold
Subject: Re: [ft-devel] [GSoC] CID font support, and others
Date: Fri, 18 Aug 2017 12:40:14 -0700
User-agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:52.0) Gecko/20100101 Thunderbird/52.2.1

Hi Werner,

You are correct that CoolType does not have the improvement that the initial hintmap was designed for. It also does not have some of the heuristics that improve rendering of complex CJK glyphs. On the other hand, CoolType has more code devoted to rendering bilevel bitmaps. (In the early days of PostScript, that was the only kind of rendering.)


On 8/15/2017 10:27 PM, Werner LEMBERG wrote:
Hello Dave,

thanks for your detailed response.

The initial hintmap feature is relatively new in Adobe's CFF
rasterizers.  It does not exist in CoolType (the rasterizer used in
Acrobat).  CoolType uses an interpreter that handles either Type 1
or CFF in one pass.  But because it does not build an initial
hintmap, it is able to process Type 1 hint declarations that occur
mid-charstring.  Hint processing in CoolType is very different from
the rasterizer that Adobe contributed to FreeType.
OK, I thought something along this line.  Given that you write

  The main motivation for the initial hintmap feature was to deal with
  distortions caused by blue zones.  [...]

I wonder whether CoolType's hinting engine produces inferior results
compared to the engine Adobe has contributed to FreeType...

I suppose you could disable the use of the initial hintmap for Type 1
charstrings only.
If I understand correctly, this is what Ewald started with, and he got
bad results...

But your two pass approach has the advantage of making the initial
hintmap feature work for Type 1.  As long as the performance impact
is acceptable, I think this is a good choice.
Thanks for confirmation!

Ewald, have you already done some benchmarks?


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