[comp.sys.mac.programmer] Bottlenecks, OpenPoly, and polySave

nebel@wam.umd.edu (Chris D. Nebel) (03/15/91)

All right.  A little experimentation with QuickDraw bottlenecks revealed that
they do indeed get called even if the pen is hidden, and that the line
bottleneck is in fact responsible for building up polygon definitions (since
MyStdPoly always wound up getting called with a polygon with no points in it!)

So: IM-1 claims that if the polySave field of the current grafPort is not NIL,
then it's a handle to the current polygon-in-progress.  Sure enough, when you
call OpenPoly, polySave becomes non-NIL.  Trouble is, it gets a value of 1!
(NOT a legal handle :-/)  So my question is: what is going on here?  I get a
normal handle back from OpenPoly, but how does Quickdraw know where it is
afterwards?  More to the point, how can _I_ know? (without using a global
variable, that is)  Why is polySave == 1?  And is any of this actually
documented anywhere?

Oh, yes. And how am I supposed to go about building regions?

Thanks,
Chris Nebel
nebel@wam.umd.edu