Re: [ft-devel] [patch] emboldening rework v1

[Alexei Podtelezhnikov]

On Thu, Apr 19, 2012 at 2:12 PM, Behdad Esfahbod <address@hidden> wrote:
> On 04/18/2012 01:36 PM, Alexei Podtelezhnikov wrote:
>> When we talk about an outline as a collection of contours, things get
>> out of control very quickly, because to do a good job you have to
>> inspect the whole layout of contours. For example the orientations of
>> both contours is the same in "=" and different in "o". So we may rely
>
> Actually no.  Now I guess *you* got confused the same way that I got!  In '=',
> each contour can have whatever direction it wants.  Non-zero winding renders
> all four possibilities fine.

There is a difference between what the FreeType renderer can handle,
and what is strandard. The opposite orientation of two contours in "="
would be a font bug.

>> on EITHER the orientation of the contour with the largest area OR the
>> the sum of all contour areas.
>>
>> So here is my simple suggestion. Return NONE when the orientation
>> according to the the largest contour is not the same as the
>> orientation according to the sum of all.
>
> This will result in false positives, and that's bad.

What do you call false positives? I disagree if you refer to a buggy
font that FreeType can render.

>> Thoughts? Once again, the current implementation is broken so it is
>> not like we need to care about backwards compatibility.
>
> It isn't impossible to detect the direction of all outer contours, but is much
> more involved than your signed-area-based algorithm indeed.

I'm starting to see some need for the diagnostic function. Perhaps, so
many buggy fonts are out there because FreeType and others never
provided such API.

> Perhaps the question to be answered is, is anyone using that API right now?

Internally, only the emboldener and the stroker uses this function.
The renderers are immune.