[pdftex] Type 1 font problem

[Allin Cottrell]

On Sun, 21 Jan 2018, Allin Cottrell wrote:

> On Sun, 21 Jan 2018, Karl Berry wrote:
>
[...]
>> Looking at http://users.wfu.edu/cottrell/t1problem/caslon_bad.png, that
>> is strange output, to me more indicative of a bug in the font rendering
>> on system B than anything else.  I doubt it is a problem in the PDF,
>> because the PDF just says "display these characters from this font".
[...]
>
> Thanks, Karl (and also George White). I'll try to follow your advice 
> and will report back if I find anything definitive.

Karl's diagnosis is correct: the problem is in freetype2. The test I 
reported earlier (which seemed to exonerate libfreetype) was flawed, I 
guess due to caching of shared library code.

There was a substantial change in the Type 1 rendering code in 
freetype2 between versions 2.8.1 (2017-09-16) and 2.9 (2018-01-08): a 
new "adobe" hinting engine was introduced and is now favored over the 
original "freetype" engine by default. However it's possible to build 
the library with support for the old engine by defining

T1_CONFIG_OPTION_OLD_ENGINE

in ftoption.h. In that case the "freetype" engine becomes the default 
but the "adobe" engine can be selected by exporting

FREETYPE_PROPERTIES="type1:hinting-engine=adobe"

Reliably, use of the adobe engine produces the bad results that I 
mentioned, for Adobe Caslon and Monotype Bulmer, while the freetype 
engine gives correct results.

--
Allin Cottrell
Department of Economics
Wake Forest University, NC