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From: nv89-nun@alv.nada.kth.se (Nicklas Ungman)
Newsgroups: comp.sys.mac.programmer
Subject: Re: COPYBITS
Message-ID: <NV89-NUN.91Feb23152739@alv.nada.kth.se>
Date: 23 Feb 91 14:27:41 GMT
References: <1991Feb22.032616.30166@wpi.WPI.EDU>
Sender: news@nada.kth.se (Mr News)
Organization: Royal Institute of Technology, Stockholm, Sweden
Lines: 25
In-reply-to: nuk@wpi.WPI.EDU's message of 22 Feb 91 03:26:16 GMT

The problem might be that MyMap is not properly set up.
The following procedure shuold work ok.
Also see Macintosh Technical Notes #41:Drawing into an Offscreen Bitmap.

procedure DoStuff;
var
  OffscreenPort: GrafPort;
   ...
begin
  MyMap.bounds:=SrcRect;
  MyMap.rowBytes:=((SrcRect.right - SrcRect.left + 15) div 16)*2;
  MyMap.baseAddr:=NewPtr(MyMap.rowBytes*LongInt(SrcRect.bottom - SrcRect.top));

  OpenPort(@OffScreenPort);
  SetPortBits(MyMap);

	{draw stuff}

  CopyBit(OffScreenPort.portBits,VisibleWindow^.portBits,
 			SrcRect,DestRect,0,NIL);
  ClosePort(@OffScreenPort);
end;


/Nixxon