[pdftex] Type 1 font problem

[Allin Cottrell]

On Tue, 23 Jan 2018, The Thanh Han wrote:

> On Tue, Jan 23, 2018 at 5:22 PM, Allin Cottrell <cottrell at wfu.edu> wrote:
>
>> 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.
>>
>
> It could also be a problem/bug of pdftex.​
>
> Can you please try to turn off font subsetting, so that the fonts are
> embedded entirely? If the output is ok, perhaps pdftex is doing something
> that makes adobe hinting engine unhappy.

I did think of that point: I reset pdftex.map to turn off subsetting, 
but it didn't help with the PDF display via freetype2 2.9 and the 
"adobe" engine.

> FWIW, I did a preflight check of the pdf in Adobe Acrobat Pro, and did not
> find any issue.

That's good to know!

Allin Cottrell