Daniel@0: Daniel@0: Daniel@0: Daniel@0: Daniel@0: Arrow Shapes Daniel@0: Daniel@0: Daniel@0: Daniel@0:

Arrow Shapes

Daniel@0:

Daniel@0: Arrow shapes can be specified and named using the following simple Daniel@0: grammar. Daniel@0: Terminals are shown in bold font and nonterminals in italics. Daniel@0: Literal characters are given in single quotes. Daniel@0: Square brackets [ and ] enclose optional items. Daniel@0: Vertical bars | separate alternatives. Daniel@0: Daniel@0: Daniel@0: Daniel@0: Daniel@0: Daniel@0: Daniel@0: Daniel@0: Daniel@0: Daniel@0: Daniel@0: Daniel@0: Daniel@0: Daniel@0: Daniel@0: Daniel@0: Daniel@0: Daniel@0: Daniel@0: Daniel@0: Daniel@0: Daniel@0: Daniel@0: Daniel@0: Daniel@0: Daniel@0: Daniel@0: Daniel@0: Daniel@0: Daniel@0: Daniel@0: Daniel@0: Daniel@0: Daniel@0: Daniel@0: Daniel@0: Daniel@0: Daniel@0: Daniel@0: Daniel@0: Daniel@0: Daniel@0: Daniel@0: Daniel@0: Daniel@0: Daniel@0: Daniel@0: Daniel@0: Daniel@0: Daniel@0: Daniel@0: Daniel@0: Daniel@0: Daniel@0: Daniel@0: Daniel@0: Daniel@0: Daniel@0: Daniel@0: Daniel@0: Daniel@0: Daniel@0: Daniel@0: Daniel@0: Daniel@0: Daniel@0: Daniel@0: Daniel@0: Daniel@0: Daniel@0: Daniel@0: Daniel@0:

arrowname	:	aname [ aname [ aname [ aname ] ] ]
aname	:	[ modifiers ] shape
modifiers	:	[ 'o' ] [ side ]
side	:	'l'
	\|	'r'
shape	:	box
	\|	crow
	\|	diamond
	\|	dot
	\|	inv
	\|	none
	\|	normal
	\|	tee
	\|	vee

Daniel@0:

Daniel@0: The primitive shapes are: Daniel@0:

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"box"	Daniel@0:	"crow"	Daniel@0:	"diamond"	Daniel@0:
"dot"	Daniel@0:	"inv"	Daniel@0:	"none"	Daniel@0:
"normal"	Daniel@0:	"tee"	Daniel@0:	"vee"	Daniel@0:

Daniel@0: Daniel@0:

Daniel@0: As for the modifiers: Daniel@0:

'l' Daniel@0:: Clip the shape, leaving only the part to the left of the edge. Daniel@0:
'r' Daniel@0:: Clip the shape, leaving only the part to the right of the edge. Daniel@0:
'o' Daniel@0:: Use an open (non-filled) version of the shape. Daniel@0:

Daniel@0: Left and right are defined as those directions determined by looking Daniel@0: from the edge towards the point where the arrow "touches" the node. Daniel@0:

Daniel@0: As an example, the arrow shape lteeoldiamond is parsed as Daniel@0: 'l' 'tee' 'o' 'l' 'diamond' and corresponds to the shape Daniel@0:

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Daniel@0: Daniel@0: Note that the first arrow shape specified occurs closest to the node. Daniel@0: Subsequent arrow shapes, if specified, occur further from the node. Daniel@0:

Daniel@0: Not all syntactically legal combinations of modifiers are meaningful Daniel@0: or semantically valid. Daniel@0: For example, none of the modifiers make any sense with none. Daniel@0: The following table indicates which modifiers are allowed with which shapes. Daniel@0:

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Modifier	box Daniel@0:	crow Daniel@0:	diamond Daniel@0:	dot Daniel@0:	inv Daniel@0:	none Daniel@0:	normal Daniel@0:	tee Daniel@0:	vee Daniel@0:
'l'/'r'	X	X	X		X		X	X	X
'o'	X		X	X	X		X

Daniel@0: Daniel@0:

Daniel@0: This yields 36 different arrow shapes. The optional second, third, fourth shapes Daniel@0: can independently be any of the 36, but since nonenone Daniel@0: is redundant, there are 35**4 + 35**3 + 35**2 + 35 + 1 = 1,544,761 different combinations. Daniel@0:

Daniel@0: The following display contains the 36 combinations possible with a single Daniel@0: arrow shape. The node attached to the arrow is not drawn but would appear Daniel@0: on the right side of the edge. Daniel@0:

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Daniel@0:	Daniel@0:	Daniel@0:	Daniel@0:	Daniel@0:	Daniel@0:
box Daniel@0:	lbox Daniel@0:	rbox Daniel@0:	obox Daniel@0:	olbox Daniel@0:	orbox Daniel@0:
Daniel@0:	Daniel@0:	Daniel@0:
crow Daniel@0:	lcrow Daniel@0:	rcrow Daniel@0:
Daniel@0:	Daniel@0:	Daniel@0:	Daniel@0:	Daniel@0:	Daniel@0:
diamond Daniel@0:	ldiamond Daniel@0:	rdiamond Daniel@0:	odiamond Daniel@0:	oldiamond Daniel@0:	ordiamond Daniel@0:
Daniel@0:	Daniel@0:
dot Daniel@0:	odot Daniel@0:
Daniel@0:	Daniel@0:	Daniel@0:	Daniel@0:	Daniel@0:	Daniel@0:
inv Daniel@0:	linv Daniel@0:	rinv Daniel@0:	oinv Daniel@0:	olinv Daniel@0:	orinv Daniel@0:
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none Daniel@0:
Daniel@0:	Daniel@0:	Daniel@0:	Daniel@0:	Daniel@0:	Daniel@0:
normal Daniel@0:	lnormal Daniel@0:	rnormal Daniel@0:	onormal Daniel@0:	olnormal Daniel@0:	ornormal Daniel@0:
Daniel@0:	Daniel@0:	Daniel@0:
tee Daniel@0:	ltee Daniel@0:	rtee Daniel@0:
Daniel@0:	Daniel@0:	Daniel@0:
vee Daniel@0:	lvee Daniel@0:	rvee Daniel@0:

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