Re: [ft] Rendering a filled contour inside an unfilled one

[Werner LEMBERG]

> In common to TrueType and PostScript style outlines (i.e. whichever
> combination of clockwise/anticlockwise/filled/unfilled is used) I
> would like to know how a filled contour inside an unfilled one
> (which in turn would of course be inside a filled one) such as in
> the case of © is provided by the font and handled by the
> rasterizer. Is it just that whichever is first in storage order is
> done first? For example, in the case of © the outer filled circle
> should be placed first in the font storage, then the inner unfilled
> circle, then the innermost filled C?

For the smooth rasterizer, the *whole* outline is transformed into
intersections with horizontal scan lines, then either the even/odd or
the non-zero winding rule gets applied scanline by scanline, depending
on the FT_OUTLINE_EVEN_ODD_FILL flag.

> I am trying to implement boolean operations on glyph contours, which
> is why I ask.

Please give an example.


    Werner