iflConfig(3)	  Image	Format Library C++ Reference Manual	  iflConfig(3)

NAME    [Toc]    [Back]

     iflConfig - class for pixel abstraction

INHERITS FROM    [Toc]    [Back]

     This is a base class and therefore	has no inheritance.

HEADER FILE    [Toc]    [Back]

     #include <ifl/iflConfig.h>

CLASS DESCRIPTION    [Toc]    [Back]

     The iflConfig class is used to describe the configuration of pixel	data.
     It	is used	in iflFile functions such as getTile() and setTile() to
     describe the configuration	of data	in the user's buffer.

     An	iflConfig contains six public member variables describing a collection
     of	pixels:


	  iflType dtype		      Data type	of the pixels

	  iflOrder order	      Order of the pixels

	  iflOrientation orientation  Orientation of the pixels

	  int nchans		      Number of	data channels the pixels
				      contain

	  int choff		      Offset in	the channel list for the
				      purpose of mapping from one collection
				      of channels to another.

	  int* channels		      List that	maps channels from one
				      collection to another.  This array is
				      not maintained by	this object, the data
				      pointed to must persist while the	object
				      is in use.



















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iflConfig(3)	  Image	Format Library C++ Reference Manual	  iflConfig(3)



     Using iflConfig    [Toc]    [Back]

     The iflConfig object contains a list that maps channels from one
     collection	to another.  In	this code fragment,

	  unsigned char	buffer[10*10*3];
	  static int list[] = {	2, 1, 0	};
	  iflConfig cfg(iflUChar, iflInterleaved, 3, list);

	  someFile.getTile(0, 0, 0, 10,	10, 1, buffer, &cfg);

     cfg is used to indicate that buffer is going to receive a 10-by-10	array
     of	three-component	 pixels	stored in interleaved order with an unsigned
     char data type.  This would override the actual configuration of the data
     in	someFile.

     The channel list provides the buffer's channel information. The first
     channel of	the buffer receives data from channel 2	of someFile. The
     second channel is from someFile's channel 1. The third buffer channel
     gets channel 0 of someFile.  In general, when an iflConfig	is defaulted,
     the operation being performed assumes that	the source and destination
     configurations match.  If someFile	was actually a four-channel float
     image stored in separate order, then

	  someFile.getTile(0, 0, 0, 10,	10, 1, buffer);


     would require a buffer declared as

	  float	buffer[10*10*4];

     and would receive a verbatim copy of the requested	section	of someFile.

CLASS MEMBER FUNCTION SUMMARY    [Toc]    [Back]

     Constructor

	  iflConfig()
	  iflConfig(iflDataType	type, iflOrder ord=iflInterleaved,
		    int	nchan=0, int* chanList=NULL, int chanOff=0,
		    iflOrientation ori=iflOrientation(0))


     Channel list manipulations    [Toc]    [Back]

	  void compose(int nc, int* in,	int* out) const
	  int isInvertable() const
	  void invert(int nc, int* chanList) const
	  int mapChan(int idx) const
	  int operator[](int idx) const






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iflConfig(3)	  Image	Format Library C++ Reference Manual	  iflConfig(3)

FUNCTION DESCRIPTIONS    [Toc]    [Back]

     iflConfig()

	  iflConfig()
	  iflConfig(iflDataType	type, iflOrder order=iflInterleaved,
		    int	nchan=0, int* chanList=NULL, int chanOff=0,
		    iflOrientation ori=iflOrientation(0))


	  The first constructor	creates	an uninitialized object	(not
	  recommended).	 The second constructor	creates	an iflConfig with data
	  type,	type; data ordering, order; and	channel	list defined by
	  chanList of nc channels.  If chanList	is omitted, all	nchan channels
	  are used in ascending	order.	Optionally, the	orientation is set to
	  ori.	If omitted, the	orientation matches that of the	image being
	  accessed.

     compose()

	  void compose(int nc, int* in,	int* out) const


	  This function	composes the channel list in the iflConfig object with
	  the channel list of nchan channels specified by in.  The composed
	  list is written to out.

     mapChan()

	  void mapChan(int idx)	const


	  This function	returns	the channel on the list	in the iflConfig
	  object that maps to idx. It takes into account the offset specified
	  by choff, or just the	offseted index,	if the channel list is NULL.
	  If idx is more than nchans or	less than 0, it	returns	-1.

     operator[]()

	  void operator[](int idx) const


	  This operator	returns	the channel on the list	in the iflConfig
	  object that maps to idx. It takes into account the offset specified
	  by choff, or just the	offseted index,	if the channel list is NULL.
	  If idx is more than nchans or	less than 0, it	returns	-1.

     invert()

	  void invert(int nc, int* chanList) const






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iflConfig(3)	  Image	Format Library C++ Reference Manual	  iflConfig(3)



	  This function	inverts	the channel list in the	iflConfig object to
	  perform the mapping in the opposite direction.  The result is
	  written to nc	entries	of chanlist.

     isInvertable()

	  int isInvertable() const


	  This function	returns	whether	the mapping described by the channel
	  list has an inverse.

SEE ALSO    [Toc]    [Back]

     iflFile


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