QuickDraw routine CopyBits (problems with)

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2 total messages Started by rick Thu, 13 Dec 1984 14:43

#170

Author: rick
Date: Thu, 13 Dec 1984 14:43

34 lines
1367 bytes

I encountered a problem when using CopyBits:


VAR
  MyBitMap : BitMap;
  MyPattrn : Pattern;  { 8 bits by 8 bits }


BEGIN
  MyBitMap.baseAddr:= @MyPattrn;
  MyBitMap.rowBytes:= 1;    { 8*8 pixels }
  SetRect(MyBitMap.bounds,  0,0,8,8);  { 8*8 pixels }

  CopyBits(MyBitMap,
           MyW.port.portBits,
           srcRect,
           dstRect,
           srcXor,
           NIL);      { No mask region }
END;

 
This example causes "System error 02", Address error.
It appears CopyBits cannot copy from a BitImage with
rowBytes=1. When I changed my BitImage to 16*8 pixels,
rowBytes=2, everything functioned ok. 

Does anyone know where the problem is, with me or with
QuickDraw??

Thanks in advance,
Rick Jansen
  { philabs,decvax,seismo}!mcvax!sara70!rick

Re: QuickDraw routine CopyBits (problems with)

#176

Author: William Pugh
Date: Mon, 17 Dec 1984 18:00

8 lines
832 bytes

Each row of a bit map must start on an even address, and therefor rowBytes
must be an even number.

System ID=2 means that a word-oriented operation was attempted on a odd address.


		Bill Pugh
		Cornell

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