Re: [ft-devel] Horizontal Stem Snapping in Autohinter

[Adam Twardoch (List)]

I would definitely applaud to the autohinter API, especially for
ttfautohint!

Adam

On 12-06-14 08:51, Werner LEMBERG wrote:
>> What are your thoughts on implementing horizontal stem snapping in
>> the autohinter?
> It's certainly worth an option.  BTW, if you say `make devel', the
> option AF_CONFIG_OPTION_USE_WARPER is in use which goes into a similar
> direction but trying to minimize the glyph shape distortion.  Have you
> tried that?  Do you like it?
>
>> To me, this provides a substantially cleaner look to 99.5% of
>> glyphs, particularly when the stems are between 1 and 3 pixels
>> thick.  I think this is largely the issue when people complain about
>> Freetype font rendering.
> OK.  However, this must be controllable at run time, I think.  We
> urgently need an API to control the auto-hinter!  Currently, we are
> abusing `load_flags' for that (which I've massively extended for my
> ttfautohint project, BTW), but this is not a solution because we would
> be running out of bits.  Additionally, it's ugly.
>
> A first, partial implementation of auto-hinter properties can be found
> in the `autohinter-properties' git branch.  I've implemented global
> settings which are inherited by all new faces, and local settings to
> adjust a particular face.  It's a very simple start, I think.
>
> What we also need are functions like
>
>   FT_Error
>   FT_Library_SetAutohinterProperty( FT_Library  library,
>                                     FT_Int32    property,
>                                     void*       data );
>   FT_Error
>   FT_Face_SetAutohinterProperty( FT_Face   face,
>                                  FT_Int32  property,
>                                  void*     data );
>
> to fine-tune a certain property (on the global and local scope);
> `data' is a generic pointer which contents depends on the property.
> For example, take the `increase x height for the range 5 < ppem < 15'
> property in the Infinality patches: The above functions could be used
> to manipulate the lower and upper bound (5 and 15, respectively).
>
> In our private discussion in February you replied that the Infinality
> stem-alignment stuff is not tied to the autohinter, so it might be
> worth to move my first implementation attempt to the modules
> interface, something which I haven't investigated yet.  Volunteers
> welcome!
>
>
>     Werner
>
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-- 

May success attend your efforts,
-- Adam Twardoch
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