Path: utzoo!attcan!uunet!lll-winken!lll-tis!ames!mailrus!tut.cis.ohio-state.edu!bloom-beacon!gatech!udel!rochester!cornell!uw-beaver!ssc-vax!housen
From: housen@ssc-vax.UUCP (Kevin Housen)
Newsgroups: comp.sys.mac.programmer
Subject: Selecting objects in a drawing program
Message-ID: <1997@ssc-vax.UUCP>
Date: 9 Jun 88 20:01:39 GMT
Organization: Boeing Aerospace Corp., Seattle WA
Lines: 21


Im writing a program which will have certain aspects of
an object-oriented drawing program, like MacDraw or
MacDraft.  The user will be able to draw some primitives
like lines, arcs, circles, rects etc. and will be
able to select objects and edit them. There could be lots
of objects (>1000?).  My question is - does anyone know of
an efficient algorithm for detecting which object, if any,
was selected when a mouse-down occurs?  How do programs such
as MacDraw, MacDraft, SuperPaint, etc do this?

Also, what criteria do these programs use to determine when
a polyline or polygon is selected?  MacDraw and SuperPaint
highlite the object when you click within a certain distance
of one of the lines comprising an object.  MacDrafts criterion
isnt obvious.

Any help or suggestions are appreciated.

Thanks heaps...

Kevin Housen