RE: [Devel] outlines

[Graham Asher]

John Schuch said:

<<<<<<
Are these the only values that are meaningful? What I mean is, are some
points
tagged in such a way as to say, 'don't draw a line or curve to me.' For
example, drawing
an 'O' requires drawing to ovals. How does the outline info differentiate
between
the inner and outer oval? Does it?
>>>>>>

The inner and outer curves of an 'O' are different contours, so they are not
joined together. The outline structure differentiates between contours by
storing the number of contours and the indexes of their endpoints (see the
comment to FT_Outline).

<<<<<<
Does this mean that illegal sequences are commonly found?
>>>>>>

I'm not sure. I think so, because (as I remember) there are comments in the
FreeType source code explaining workarounds for illegal cases. Another
illegal case is a contour that starts with a control point.

The point tag values other than on-curve, conic and cubic are used inside
the TrueType hinter to mark points as 'touched' by hinting routines. This is
just a bad design: the outline structure should not be used as scratch
memory by the hinter.

Graham Asher