> is there a standard wrt to outline direction?
There are two: TrueType and PostScript, which are exactly the
opposite. However, all glyphs in a font have the same orientation, so
this should be easy to handle.
> If I can assume that external outlines go in clockwise order, I
> could skip left-pointing path elements when creating the upwards
> skyline, cutting the amount of work in half.
Theoretically, you could use function `FT_Outline_Get_Orientation` to
reliably get the orientation of an outline with unknown origin. For
glyphs of a font this isn't necessary since they follow strict rules.
> Also, is there is way to detect internal curves (eg. the inner curve
> of the O glyph?).
The 'inner' outline of an 'O' glyph has exactly the opposite direction
of the outer outline. In other words, for getting the outermost
outline(s) of a glyph you can always skip such 'inner' ones.
Werner
