campoly@violet.berkeley.edu (Mr. Science) (10/20/87)
Thanks to all who responded to my query about decoding PICT files.
Here is an outline of the recommended method:
1) Read Inside Mac, Vol I, pp 197-200. The section on Customizing
QuickDraw Operations describes the low-level bottleneck procedures
which QuickDraw uses to perfom its basic graphic operations. There are
separate procedures for drawing lines, rectangles, etc.
2) Call SetStdProcs to get a QDProcs record which contains pointers
to the built-in bottleneck routines. You can then change one or
more of these pointers to point to your own routines. You must also
set the grafProcs field of the grafPort you wish to use for drawing
to point this QDProcs record.
3) The parameters to these bottleneck routines pass all the information
needed to draw a specific object. Your personal routines may perform
any desired operations on these parameters (such as storing them for
later reference or modifying them), then, if you wish to actually draw
the object, your routine can call the corresponding built-in routine.
4) Once you have everything set up, call DrawPicture with the handle
to the PICTure.
For example, in Pascal:
myProcsPtr := QDProcsPtr(NewPtr(Sizeof(QDProcs)));
SetStdProcs(myProcsPtr^);
myProcsPtr^.lineProc := @MyLineProc;
thePort^.grafProcs := myProcsPtr;
DrawPicture (thePicHandle, thePicFrame);
The procedrue MyLineProc will be called whenever a line drawing command
is encountered in the PICTure whose handle is thePicHandle.
NOTE: Parsing PICT files directly is *not* a good idea. There are
serious difficulties with this approach, not the least of which
is lack of compatibility with MAC II's (and color QuickDraw).
Once again, a BIG thank you to all who took the time to enlighten me.
Gregory Dow ARPA: campoly@violet.berkeley.edu
Chemical Engineering Dept. UUCP: {uwvax, decvax, ihnp4, ...}!ucbvax
University of California !campoly%violet.berkeley.edu
Berkeley, CA 94720 BITNET: POLYDOW@UCBCMSA