[metapost] glyph operator and contours order

[Taco Hoekwater]

On 02/05/2011 04:02 PM, Laurent Méhats wrote:
>
> I believe that glyph contours don't intersect each-other, nor
> self-intersect (is that always true ?),

That should be true, otherwise it is not a proper Type 1 font.
But that is not quite the same as 'always': fonts that break this
rule can exist and even though they are not valid, they would
probably still work in everything except drawing programs.
It should be extremely rare, though.

> so my question would be: given two
> non intersecting nor self-intersecting cycles, is there a proper way to
> decide whether one lies inside the other ?

Not easily. I vaguely recall that there was some test code
based on a discussion a year or so ago on the list, but I
cannot find it any more.

The correct solution would be for metapost to allow non-continuous
paths and even/odd fill rules, then change the output of 'glyph'
accordingly. That extension is indeed planned, but not for the next
release.

Best wishes,
Taco