# The following diagrams show the CCD geometry for the different readout modes.
#
# Single readout:
#				G
#		<-------------------------------->
#			    A		    F	 
#		<----------------------><-------->
#		 B 	     	     C   D      E
#		<->                 <--><>      <>
#	^   ^	+-----------------------+--------+  ^	^
#	|   |	|   		     	| 	 |  | e	|
#	| c |	|   		     	|--------|  v  	|
#	|   v	|  +----------------+   ||      ||      |
#	|    	|  |		    |	||  o	||    	|
#	|    	|  |		    |	||  v	||    	|
#	|    	|  |		    |	||  e	||    	|
#     a	|    	|  |		    |	||  r	||      | f
#	|    	|  |		    |	||  s	||    	|
#	|    	|  |		    |	||  c	||    	|
#	|    	|  |		    |	||  a	||    	|
#	|    	|  +----------------+   ||  n   ||    	|
#	|   ^	|   		     	|--------|   	|
#	| b |   |                       |        |  ^	|
#	|   |	|   		     	| 	 |  | d	|
#	v   V	*-----------------------+--------+  v	v
#
# Quad readout (single frame):
#				G'
#		<--------------------------------->
#		     A/2    F/2  F/2      A/2
#		<---------><---><---><----------->
#		 B 	   D   2*E   D         C
#		<->        <>  < >  <> 	     <-->
#	^   ^	*----------+----.----+------------* ^	^
#	|   |	|   	   |    .    |            | | e	|
#	| c |	|   	   |----.----|            | v	|
#	|   v	|  +-------+|  |.|  |+--------+   |   	|
#  a/2	|    	|  |	   ||o |.|o ||        |   |  	| f/2
#	|    	|  |   3   ||v |.|v ||   4    |   |   	|
#	|    	|  |	   ||  |.|  ||        |   |  	|
#	|    	|  |	   ||3 |.|4 ||        |   |  	|
#       V    	...................................   	v
#	^    	|  |	   ||o |.|o ||        |   |  	^
#	|    	|  |   1   ||v |.|v ||   2    |   |  	|
#	|    	|  |	   ||  |.|  ||        |   |   	|
#   a/2	|    	|  +-------+|1 |.|2 |+--------+   |  	| f/2
#	|   ^	|          ||  |.|  ||            |  	|
#	| b |	|   	   |----.----|            | ^	|
#	|   |	|   	   |    .    |            | | d	|
#	v   v	*----------+----.----+------------* v	V
#
#
# Quad readout (four frames):
#
#		       G"			G"
#		<-------------->        <---------------->
#		     A/2     F/2         F/2      A/2
#		<---------><---->       <----><---------->
#		 B 	   D   E        E   D          C
#		<->        <>  <>	<>  <>	      <-->
#	^   ^	*----------+----+	+----+------------* ^	^
#	|   |	|   	   |    |	|    |            | | e	|
#	| c |	|   	   |----|	|----|            | v	|
#   a/2	|   v	|  +-------+|  ||	||  |+--------+   | ^ 	|
#	|    	|  |	   ||o ||	||o ||        |   | |	| f/2
#	|    	|  |   3   ||v ||	||v ||   4    |   | |	|
#	|    	|  |	   ||  ||	||  ||        |   | |	|
#	V    	|  |	   ||3 ||	||4 ||        |   | |	|
#		+---------------+       +-----------------+ v	v
#
#
#            	+---------------+	+-----------------+ ^	^
#	^    	|  |	   ||o ||	||o ||        |   | |	|
#	|    	|  |   1   ||v ||	||v ||   2    |   | |	|
#	|    	|  |	   ||  ||	||  ||        |   | |	|
#	|    	|  +-------+|1 ||	||2 |+--------+   | |	| f/2
#   a/2	|   ^	|          ||  ||	||  ||            | v	|
#	| b |	|   	   |----|	|----|            | ^	|
#	|   |	|   	   |    |	|    |            | | d	|
#	v   v	*----------+----+	+----+------------* v	v
#
# Where
#		A  = xdata			a = ydata
#		B  = txskip1			b = tyskip1
#		C  = txskip2			c = tyskip2
#		D  = bxskip1			d = byskip1
#		E  = bxskip2			e = byskip2
#		F  = xover			f = yover = a
#		G  =  A + F
#		G' =  A + F
#		G" = (A + F) / 2