Path: utzoo!attcan!uunet!samsung!aplcen!haven!mimsy!mojo!russotto
From: russotto@eng.umd.edu (Matthew T. Russotto)
Newsgroups: comp.sys.mac.programmer
Subject: Re: ARGH!! Trivial Question; Please Help
Message-ID: <1990Mar13.174129.12874@eng.umd.edu>
Date: 13 Mar 90 17:41:29 GMT
References: <KKZF972@xavier.swarthmore.edu> <16616@well.sf.ca.us> <34996@cci632.UUCP>
Sender: news@eng.umd.edu (The News System)
Organization: Maryversity of Uniland, College Park
Lines: 33

In article <34996@cci632.UUCP> ph@cci632.UUCP (Pete Hoch) 
writes:
>> Nick Jackiw writes:
>> _>I've been knocking myself out over a simple (stupid) question:
>
>Question about using PixMapHandles in Copybits.
>
>David Phillip Oster replies:
>> The correct call is:
>> 	HLock(Handle(srcPixMapHandle));
>> 	HLock(Handle(destPixMapHandle));
>> 	CopyBits(BitMapHandle(srcPixMapHandle)^^,
>> 		 BitMapHandle(destPixMapHandle)^^,
>> 		 srcRect, destRect, srcCopy, NIL);
>> 	HUnlock(Handle(srcPixMapHandle));
>> 	HUnlock(Handle(destPixMapHandle));
>
>I have some friends who disagree with this and I will try to argue
>their point.  Who said you have to lock the handles before calling
>CopyBits?  I have never seen sample code from Apple that does this.
>In fact the brand new publication from Apple "Develop" has code
>samples that use CopyBits with PixMapHandles and they DO NOT lock
>the Handles.  I think, but have no proof that CopyBits checks
>the Bit/PixMap type, (it has to do this anyway) and if it is a
>PixMapHandle then CopyBits takes care of the memory management
>problems, (if there are any) for you.

Lock the handles.  Portbits is a special case-- you pass it a POINTER
to a HANDLE to a PIXMAP, instead of the usual pointer to PixMap or 
pointer to BitMap.  I think Copybits detects this situation.
And before someone at DTS jumps all over me for this, I've tried it.
--
Matthew T. Russotto	russotto@eng.umd.edu	russotto@wam.umd.edu
][, ][+, ///, ///+, //e, //c, IIGS, //c+ --- Any questions?