Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!wuarchive!kuhub.cc.ukans.edu!mlab2
From: mlab2@kuhub.cc.ukans.edu
Newsgroups: comp.sys.mac.programmer
Subject: Re: An itsy bitsy question...
Message-ID: <27725.2787e3d0@kuhub.cc.ukans.edu>
Date: 7 Jan 91 08:58:24 GMT
References: <La6cV1w164w@questor.wimsey.bc.ca>
Organization: University of Kansas Academic Computing Services
Lines: 37

In article <La6cV1w164w@questor.wimsey.bc.ca>, aberno@questor.wimsey.bc.ca (Anthony Berno) writes:
> I was wondering about something, partly from curiosity and partly because 
> I am thinking of using it myself...
> 
> How is the "rubberbanding" done in programs like Superpaint when you are 
> drawing a line on the screen? There isn't an obvious solution in Inside
> Macintosh, and any solutions I have come up with are hideously difficult.
> There must be a relatively simple way of doing it. Does anyone out there
> know?
> 
> Thanks.
> Anthony Berno.

When in line-drawing-mode, a mouseDown event in the drawing window should call
a procedure similar to the below:

procedure RubberBand;
  var
    originalPt, lastPt, newPt : Point;
begin
  GetMouse(originalPoint);
  PenMode(patXOr);
  GetMouse(lastPt);
  MoveTo(originalPt.h, originalPt.v);
  LineTo(lastPt.h, lastPt.v);
  repeat
    MoveTo(originalPt.h, originalPt.v);
    LineTo(lastPt.h, lastPt);
    GetMouse(newPt);
    MoveTo(originalPt.h,originalPt.v);
    LineTo(newPt.h, newPt.v);
    lastPt:=newPt;
  until (not Button);
  PenNormal;
end; 

john calhoun