Re: [ft-devel] State of TrueType interpreter v38 and up?

[Werner LEMBERG]

>> (a) ignore changes of the horizontal advance widths due to hinting
>>     instructions (not implemented yet), and
>>
>> (b) ensure that all instructions behave correctly even if the
>>     horizontal resolution is increased (this is ClearType
>>     compatibility mode, already implemented).
>
> Ah, okay :) is (a) so complicated or is it that simply nobody did
> the work yet?

It's the latter.  A possible solution is to add a new FT_LOAD_XXX
flag.

> So I guess ClearType
>
> - without stem darkening: let font modify x-coordinates at will but
>   ignore modifications to advance width

Yes, see above.

> - with stem-darkening: nop everything that deals with x-coordinates
>   and embolden just the x-axis? Dave?  The latter would make
>   backwards compatibility irrelevant because we would only honor
>   Y-hints anyway, right?

I think it's not that easy, since you have to correctly handle
diagonal moves.  Instead, I can imagine that all hints are executed,
then the horizontal coordinates are reset to the unhinted ones, and
stem emboldening gets applied instead.


    Werner