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Re: Groups in Picts

Sub:    Re: Groups in Picts
To:     Henry Lieberman
From:   Steve Mitchell
Date:   12/22/91
> I am writing a Lisp interface to Mac Pict objects, ...
> Where is the information about groups?  If two graphic objects are
> grouped [say in MacDraw], then transferred via the clipboard to
> some other application [say, Canvas, Fullwrite, etc.] that has a
> group operation, the groups information is preserved. ... Could it
> perhaps be in the [uninterpreted] so-called "picture comments", and if
> so, is its format documented?
Yes, it's in the picture comments.
Grouping and a few other declarations started with MacDraw way back when.
They were originally documented in Tech Note #27. It was withdrawn in
August, 1989, after Apple handed MacDraw over to Claris. It looks like
other Mac programs are following the MacDraw conventions.
The group picture comments are "short" comments - $00A0 followed by
the kind word:
picGrpBeg =140     Begin a group
picGrpEnd =141     End a group
These may be nested.
MacDraw also requires a picDwgBeg comment between the version # and
the ClipRgn OpCodes, and a picDwgEnd before the EndOfPicture OpCode:
picDwgBeg =130     Begin a MacDraw Picture
picDwgEnd =131     End a MacDraw Picture
This says the picture contains MacDraw picture comments.
This may be enough to get you started although doubtless you'll want to
get the latest dox from Claris (I don't have them). To contact Claris,
try calling 1-800-729-2292 ext 20 and asking for the main number.
Incidentally, I have simple picture-object-oriented cut, copy and paste
for PICTs working on top of your conversion of pict-scrap.lisp - I'll
send it to you if you haven't already done it. I'm interested in knowing
more about the progress of your Lisp/Pict interface; each time I need a
piece, I'm faced with writing it!