Re: [ft-devel] various Type 1 -> CFF issues

[Werner LEMBERG]

>> * Make the old type 1 driver optional.  The file `ftt1drv.h' is
>>   talking about a `T1_CONFIG_OPTION_OLD_ENGINE' configuration
>>   macro, however, this isn't implemented yet.
> 
> I had actually implemented it, but did not commit later on, c.f.
>   http://lists.nongnu.org/archive/html/freetype-devel/2017-07/msg00010.html

Ah, ok.

> I had decided that since the new engine incurs so much overhead it
> would not be good to use it for scanning advance widths.  The old
> routine rightly does not initialise any of the glyph rendering
> objects, but it would take considerable changes to the new engine to
> do the same, which I felt was not worth it.

Mhmm.  Getting advance widths quickly is something quite important, I
believe.

> I could extract the advance width processing from the old
> interpreter into a separate function, which gets always compiled in,
> with the rest switched by the macro.

Please proceed!  I think it would be good to isolate the old Type1
engine as much as possible.

>> * Implement the `hinting-engine' property for the `type1' module.
>>
>> * `FT_PARAM_TAG_RANDOM_SEED' is defined twice (in `ftt1drv.h' and
>>   `ftcffdrv.h').  I think this should be removed – all properties
>>   for the new Type 1 engine should be in `ftcffdrv.h' only, and
>>   it's not worth to add random seed control to the old engine.  Do
>>   you agree?
> 
> I think so too - this is something I overlooked when copying the
> file over from `ftcffdrv.h'. I had renamed the class to PS_Driver,
> which all three drivers are now using.

OK.

> The only property there is `hinting_engine'.  I differentiated
> `FT_T1_HINTING_' from `FT_CFF_HINTING_', but maybe we can just use
> `FT_PS_HINTING_' for both.

Please select a solution that you think fits best.  For me it's
important to have a possibility to switch between the old and new
engines, both for testing and demonstration purposes in the demo
programs – and by default only the new engine should be available.


    Werner