Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!uunet!seas.gwu.edu!viraf
From: viraf@seas.gwu.edu (Viraf Bankwalla)
Newsgroups: comp.sys.mac.programmer
Subject: RE: Need PICT help
Message-ID: <1837@sparko.gwu.edu>
Date: 4 May 90 19:20:27 GMT
Reply-To: viraf@seas.gwu.edu ()
Organization: The George Washington University, Washington D.C.
Lines: 71

Hi,

I'm writing a program which can load in various PICT files.  My problem
lies in determining the characteristics of the source.  There are three
types of PICT files (or so I think) 

	versionOne	// BitImage.  Old style PICT
	versionTwo	// PixMap.  Support for color.
	   Chunky	   // CLUT - supports {1, 2, 4, 8} bits per pixel
	   RGBDirect	   // Direct - supports {16, 32} bits per pixel.

OK.  So I open up the 'PICT' file, and look at the header

	int	picSize;	// low word of picture size
	Rect	picFrame;	// picture frame in 72dpi
	switch (version) {
	    case versionOne:	// opcodes are one byte long
		opVersion = 0x11		// version opcode
		    0x01			// DATA - version number
		OPCODE - BYTE			// OPCODES followed by DATA
	 	    DATA
		OPCODE - BYTE
	 	    DATA
		    ::::
		    ::::
		    ::::
		opEndPic = 0xFF			// End of picture opcode

	    case versionTwo:	// opcodes are one word long
		opVersion = 0x0011		// version opcode
		    0x02FF			// DATA - version number
		HeaderOp = 0x0C00		// Version2 PICT have a header
						// before playback defination
		    DATA - 24 bytes
		:::::::
		:::::::
		opPicEnd = 0x00ff		// End of picture
	}

    The 24 bytes of data is defined as 

	longint	Version2 = -1
	unsigned hex longint	// Fixed point bounding box
	unsigned hex longint
	unsigned hex longint
	unsigned hex longint
	longint	Version2 = -1	// RESERVED


	Distinguishing between versionOne and versionTwo is easy.  
If versionOne I allocate memory for a BitMap.  I need to distinguish
between a RGBDirect and Chunky PICT so that I may create and
appropiate GDevice, and allocate memory for the PixMap.  It would 
be nice to be able to get the pixMap struct, and intrepret it.

Any suggestions ???  I thought of replacing StdBits as it provides the
source pixMap (dest = current port), but then I'd have to spool in the
PICT twice - once to gather info and then to actually draw it.  Is there
a better way ?? What should one do if the destination is composed from
two sources which have different resolutions ??  

Apple strongly recommends letting QuickDraw parse the picture, and
thus I dont want to sit down putting YACC to work.

Any help would be greatly appreciated.  

Thanks once again.

						viraf bankwalla
						viraf@seas.gwu.edu
						uunet!gwusun!viraf