Re: [ft-devel] ttfautohint: How to install

[vernon adams]

FYI i had noticed a possible issue with the sizing in relation to the 'fpgm' on 
all tffautohint generated fonts. When i check them in 'OTMaster', the 
'maxSizeOfInstructions' is flagged up by OTMaster as in need of fixing, e.g. 
the ttfautohint version of Ubuntu Font gives a size of 1013; that OTMaster 
autocorrects to 2636 to match the fpgm. Not sure how relevant that could be, as 
correcting/not correcting this seemed to not effect the fonts' render 
performance at all.

I tested the dummy font. It actually didn't render at all under DirectWrite 
(FFox5) !?, but did under GDI, see shot below;

On 30 Jun 2011, at 11:16, Werner LEMBERG wrote:

>> 
>> The 'final image' is simply the ttfautohint instructions with the
>> addition of links (double links work best in this instance). I did
>> no extra hinting from fontlab - [...]
>> 
>> [...] if i look at the same font in FontForge's Gridfitmode, then i
>> don't see the egging issue at all.
> 
> Exactly!  Such a big deviation between the rendering results indicates
> a severe problem IMHO.
> 
> The only possible explanation I have so far is that the MS Windows
> rasterizer never sees the IUP[y].  It's the last instruction in the
> `fpgm' table, only followed by a final ENDF.  Maybe I've somehow
> incorrectly implemented the generation of this SFNT table, but ttx
> doesn't show any error, and a round-conversion gives the same size and
> checksum of the `fpgm' table...
> 
> Just to be sure that an incorrect `fpgm' size isn't the problem I ask
> you to try the attached font.  With FontForge, I've stripped off all
> glyphs but uppercase `O', then I've disassembled it with ttx, omitting
> the `FFTM', `GDEF', `GPOS', and `GSUB' tables, then added a dummy
> function at the end of the `fpgm' table to make it bigger, and finally
> assembled it again with ttx.