Node, Edge and Graph Attributes

The table below describes the attributes used by various Graphviz tools. The table gives the name of the attribute, the graph components (node, edge, etc.) which use the attribute and the type of the attribute (strings representing legal values of that type). Where applicable, the table also gives a default value for the attribute, a minimum allowed setting for numeric attributes, and certain restrictions on the use of the attribute.

Note that attribute names are case-sensitive. This is usually true for attribute values as well, unless noted.

All Graphviz attributes are specified by name-value pairs. Thus, to set the fillcolor of a node abc, one would use

abc [fillcolor = red]

Similarly, to set the arrowhead style of an edge abc -> def, one would use:

abc -> def [arrowhead = diamond]

Further details concerning the setting of attributes can be found in the description of the DOT language.

At present, most device-independent units are either inches or points, which we take as 72 points per inch.

Note: Some attributes, such as dir or arrowtail, are ambiguous when used in DOT with an undirected graph since the head and tail of an edge are meaningless. As a convention, the first time an undirected edge appears, the DOT parser will assign the left node as the tail node and the right node as the head. For example, the edge A -- B will have tail A and head B. It is the user’s responsibility to handle such edges consistently. If the edge appears later, in the format

B -- A [taillabel = "tail"]

the drawing will attach the tail label to node A. To avoid possible confusion when such attributes are required, the user is encouraged to use a directed graph. If it is important to make the graph appear undirected, this can be done using the dir, arrowtail or arrowhead attributes.

The tools accept standard C representations for int and double types. For the bool type, TRUE values are represented by true or yes (case-insensitive) and any non-zero integer, and FALSE values by false or no (case-insensitive) and zero. In addition, there are a variety of specialized types such as arrowType, color, point and rankdir. Legal values for these types are given at the end.

In the Used By field, the characters E, N, G, S and C represent edges, nodes, the root graph, subgraphs and cluster subgraphs, respectively. This field indicates which graph component uses the attribute.

In the Notes field, an annotation of write only indicates that the attribute is used for output, and is not used or read by any of the layout programs.

Name	Used By	Type	Default	Minimum	Notes
_background	G	string	<none>
area	NC	double	1.0	>0	patchwork only
arrowhead	E	arrowType	normal
arrowsize	E	double	1.0	0.0
arrowtail	E	arrowType	normal
bb	G	rect			write only
bgcolor	GC	color colorList	<none>
center	G	bool	false
charset	G	string	"UTF-8"
class	ENCG	string	""		svg only
clusterrank	G	clusterMode	local		dot only
color	ENC	color colorList	black
colorscheme	ENCG	string	""
comment	ENG	string	""
compound	G	bool	false		dot only
concentrate	G	bool	false
constraint	E	bool	true		dot only
Damping	G	double	0.99	0.0	neato only
decorate	E	bool	false
defaultdist	G	double	1+(avg. len)*sqrt(\|V\|)	epsilon	neato only
dim	G	int	2	2	sfdp, fdp, neato only
dimen	G	int	2	2	sfdp, fdp, neato only
dir	E	dirType	forward(directed) none(undirected)
diredgeconstraints	G	string bool	false		neato only
distortion	N	double	0.0	-100.0
dpi	G	double	96.0 0.0		svg, bitmap output only
edgehref	E	escString	""		svg, map only
edgetarget	E	escString	<none>		svg, map only
edgetooltip	E	escString	""		svg, cmap only
edgeURL	E	escString	""		svg, map only
epsilon	G	double	.0001 * # nodes(mode == KK) .0001(mode == major) .01(mode == sgd)		neato only
esep	G	addDouble addPoint	+3		not dot
fillcolor	NEC	color colorList	lightgrey(nodes) black(clusters)
fixedsize	N	bool string	false
fontcolor	ENGC	color	black
fontname	ENGC	string	"Times-Roman"
fontnames	G	string	""		svg only
fontpath	G	string	system-dependent
fontsize	ENGC	double	14.0	1.0
forcelabels	G	bool	true
gradientangle	NCG	int	""
group	N	string	""		dot only
head_lp	E	point			write only
headclip	E	bool	true
headhref	E	escString	""		svg, map only
headlabel	E	lblString	""
headport	E	portPos	center
headtarget	E	escString	<none>		svg, map only
headtooltip	E	escString	""		svg, cmap only
headURL	E	escString	""		svg, map only
height	N	double	0.5	0.02
href	GCNE	escString	""		svg, postscript, map only
id	GCNE	escString	""		svg, postscript, map only
image	N	string	""
imagepath	G	string	""
imagepos	N	string	"mc"
imagescale	N	bool string	false
inputscale	G	double	<none>		fdp, neato only
K	GC	double	0.3	0	sfdp, fdp only
label	ENGC	lblString	"\N" (nodes) "" (otherwise)
label_scheme	G	int	0	0	sfdp only
labelangle	E	double	-25.0	-180.0
labeldistance	E	double	1.0	0.0
labelfloat	E	bool	false
labelfontcolor	E	color	black
labelfontname	E	string	"Times-Roman"
labelfontsize	E	double	14.0	1.0
labelhref	E	escString	""		svg, map only
labeljust	GC	string	"c"
labelloc	NGC	string	"t"(clusters) "b"(root graphs) "c"(nodes)
labeltarget	E	escString	<none>		svg, map only
labeltooltip	E	escString	""		svg, cmap only
labelURL	E	escString	""		svg, map only
landscape	G	bool	false
layer	ENC	layerRange	""
layerlistsep	G	string	","
layers	G	layerList	""
layerselect	G	layerRange	""
layersep	G	string	":\t "
layout	G	string	""
len	E	double	1.0(neato) 0.3(fdp)		fdp, neato only
levels	G	int	MAXINT	0.0	sfdp only
levelsgap	G	double	0.0		neato only
lhead	E	string	""		dot only
lheight	GC	double			write only
lp	EGC	point			write only
ltail	E	string	""		dot only
lwidth	GC	double			write only
margin	NCG	double point	<device-dependent>
maxiter	G	int	100 * # nodes(mode == KK) 200(mode == major) 30(mode == sgd) 600(fdp)		fdp, neato only
mclimit	G	double	1.0		dot only
mindist	G	double	1.0	0.0	circo only
minlen	E	int	1	0	dot only
mode	G	string	major		neato only
model	G	string	shortpath		neato only
mosek	G	bool	false		neato only
newrank	G	bool	false		dot only
nodesep	G	double	0.25	0.02
nojustify	GCNE	bool	false
normalize	G	double bool	false		not dot
notranslate	G	bool	false		neato only
nslimit	G	double			dot only
nslimit1	G	double			dot only
ordering	GN	string	""		dot only
orientation	NG	double string	0.0 ""	360.0
outputorder	G	outputMode	breadthfirst
overlap	G	string bool	true		not dot
overlap_scaling	G	double	-4	-1.0e10	prism only
overlap_shrink	G	bool	true		prism only
pack	G	bool int	false
packmode	G	packMode	node
pad	G	double point	0.0555 (4 points)
page	G	double point
pagedir	G	pagedir	BL
pencolor	C	color	black
penwidth	CNE	double	1.0	0.0
peripheries	NC	int	shape default(nodes) 1(clusters)	0
pin	N	bool	false		fdp, neato only
pos	EN	point splineType
quadtree	G	quadType bool	normal		sfdp only
quantum	G	double	0.0	0.0
rank	S	rankType			dot only
rankdir	G	rankdir	TB		dot only
ranksep	G	double doubleList	0.5(dot) 1.0(twopi)	0.02	twopi, dot only
ratio	G	double string
rects	N	rect			write only
regular	N	bool	false
remincross	G	bool	true		dot only
repulsiveforce	G	double	1.0	0.0	sfdp only
resolution	G	double	96.0 0.0		svg, bitmap output only
root	GN	string bool	<none>(graphs) false(nodes)		circo, twopi only
rotate	G	int	0
rotation	G	double	0		sfdp only
samehead	E	string	""		dot only
sametail	E	string	""		dot only
samplepoints	N	int	8(output) 20(overlap and image maps)
scale	G	double point			not dot
searchsize	G	int	30		dot only
sep	G	addDouble addPoint	+4		not dot
shape	N	shape	ellipse
shapefile	N	string	""
showboxes	ENG	int	0	0	dot only
sides	N	int	4	0
size	G	double point
skew	N	double	0.0	-100.0
smoothing	G	smoothType	"none"		sfdp only
sortv	GCN	int	0	0
splines	G	bool string
start	G	startType	""		fdp, neato only
style	ENCG	style	""
stylesheet	G	string	""		svg only
tail_lp	E	point			write only
tailclip	E	bool	true
tailhref	E	escString	""		svg, map only
taillabel	E	lblString	""
tailport	E	portPos	center
tailtarget	E	escString	<none>		svg, map only
tailtooltip	E	escString	""		svg, cmap only
tailURL	E	escString	""		svg, map only
target	ENGC	escString string	<none>		svg, map only
tooltip	NEC	escString	""		svg, cmap only
truecolor	G	bool			bitmap output only
URL	ENGC	escString	<none>		svg, postscript, map only
vertices	N	pointList			write only
viewport	G	viewPort	""
voro_margin	G	double	0.05	0.0	not dot
weight	E	int double	1	0(dot,twopi) 1(neato,fdp)
width	N	double	0.75	0.01
xdotversion	G	string			xdot only
xlabel	EN	lblString	""
xlp	NE	point			write only
z	N	double	0.0	-MAXFLOAT -1000

Attribute Descriptions

_background : string, default: <none>

A string in the xdot format specifying an arbitrary background.
During rendering, the canvas is first filled as described in the bgcolor attribute.

Then, if _background is defined, the graphics operations described in the string are performed on the canvas.

Valid for: Graphs.

area : double, default: 1.0, minimum: >0

Indicates the preferred area for a node or empty cluster when laid out by patchwork.

Valid for: Clusters, Nodes. Note: patchwork only

arrowhead : arrowType, default: normal

Style of arrowhead on the head node of an edge. This will only appear if the dir attribute is forward or both.

See the limitation.

Valid for: Edges.

arrowsize : double, default: 1.0, minimum: 0.0

Multiplicative scale factor for arrowheads.

Valid for: Edges.

arrowtail : arrowType, default: normal

Style of arrowhead on the tail node of an edge. This will only appear if the dir attribute is back or both.

See the limitation.

Valid for: Edges.

bb : rect

Bounding box of drawing in points.

Valid for: Graphs. Note: write only

bgcolor : color|colorList, default: <none>

When attached to the root graph, this color is used as the background for entire canvas.

When a cluster attribute, it is used as the initial background for the cluster. If a cluster has a filled style, the cluster’s fillcolor will overlay the background color.

If the value is a colorList, a gradient fill is used. By default, this is a linear fill; setting style=radial will cause a radial fill. Only two colors are used. If the second color (after a colon) is missing, the default color is used for it. See also the gradientangle attribute for setting the gradient angle.

For certain output formats, such as PostScript, no fill is done for the root graph unless bgcolor is explicitly set.

For bitmap formats, however, the bits need to be initialized to something, so the canvas is filled with white by default. This means that if the bitmap output is included in some other document, all of the bits within the bitmap’s bounding box will be set, overwriting whatever color or graphics were already on the page. If this effect is not desired, and you only want to set bits explicitly assigned in drawing the graph, set bgcolor="transparent".

Valid for: Clusters, Graphs.

center : bool, default: false

If true, the drawing is centered in the output canvas.

Valid for: Graphs.

charset : string, default: "UTF-8"

Specifies the character encoding used when interpreting string input as a text label.

The default value is "UTF-8". The other legal value is "iso-8859-1" or, equivalently, "Latin1".

The charset attribute is case-insensitive.

Note that if the character encoding used in the input does not match the charset value, the resulting output may be very strange.

Valid for: Graphs.

class : string, default: ""

Classnames to attach to the node, edge, graph, or cluster’s SVG element. Combine with stylesheet for styling SVG output using CSS classnames.

Multiple space-separated classes are supported.

Example:

digraph G {
  graph [class="cats"];

  subgraph cluster_big {
    graph [class="big_cats"];

    "Lion" [class="yellow social"];
    "Snow Leopard" [class="white solitary"];
  }
}

Valid for: Clusters, Edges, Graphs, Nodes. Note: svg only

clusterrank : clusterMode, default: local

Mode used for handling clusters. If clusterrank=local, a subgraph whose name begins with cluster is given special treatment.

The subgraph is laid out separately, and then integrated as a unit into its parent graph, with a bounding rectangle drawn about it. If the cluster has a label parameter, this label is displayed within the rectangle.

Note also that there can be clusters within clusters.

The modes clusterrank=global and clusterrank=none appear to be identical, both turning off the special cluster processing.

Valid for: Graphs. Note: dot only

color : color|colorList, default: black

Basic drawing color for graphics, not text. For the latter, use the fontcolor attribute.

For edges, the value can either be a single color or a colorList.

In the latter case, if colorList has no fractions, the edge is drawn using parallel splines or lines, one for each color in the list, in the order given.

The head arrow, if any, is drawn using the first color in the list, and the tail arrow, if any, the second color. This supports the common case of drawing opposing edges, but using parallel splines instead of separately routed multiedges.

If any fraction is used, the colors are drawn in series, with each color being given roughly its specified fraction of the edge.

For example, the graph:

digraph G {
  a -> b [dir=both color="red:blue"]
  c -> d [dir=none color="green:red;0.25:blue"]
}

yields:

Valid for: Clusters, Edges, Nodes.

colorscheme : string, default: ""

This attribute specifies a color scheme namespace: the context for interpreting color names.

In particular, if a color value has form "xxx" or "//xxx", then the color xxx will be evaluated according to the current color scheme. If no color scheme is set, the standard X11 naming is used.

For example, if colorscheme=bugn9, then color=7 is interpreted as color="/bugn9/7".

Valid for: Clusters, Edges, Graphs, Nodes.

comment : string, default: ""

Comments are inserted into output. Device-dependent

Valid for: Edges, Graphs, Nodes.

compound : bool, default: false

If true, allow edges between clusters.

See lhead and ltail below.

Valid for: Graphs. Note: dot only

concentrate : bool, default: false

If true, use edge concentrators.

This merges multiedges into a single edge and causes partially parallel edges to share part of their paths. The latter feature is not yet available outside of dot.

Valid for: Graphs.

constraint : bool, default: true

If false, the edge is not used in ranking the nodes. For example, in the graph:

digraph G {
  a -> c;
  a -> b;
  b -> c [constraint=false];
}

the edge b -> c does not add a constraint during rank assignment, so the only constraints are that a be above b and c, yielding the graph:

Valid for: Edges. Note: dot only

Damping : double, default: 0.99, minimum: 0.0

Factor damping force motions. On each iteration, a node’s movement is limited to this factor of its potential motion. By being less than 1.0, the system tends to “cool”, thereby preventing cycling.

Valid for: Graphs. Note: neato only

decorate : bool, default: false

If true, attach edge label to edge by a 2-segment polyline, underlining the label, then going to the closest point of spline.

Valid for: Edges.

defaultdist : double, default: 1+(avg. len)*sqrt(|V|), minimum: epsilon

This specifies the distance between nodes in separate connected components. If set too small, connected components may overlap.

Only applicable if pack=false.

Valid for: Graphs. Note: neato only

dim : int, default: 2, minimum: 2

Set the number of dimensions used for the layout.

The maximum value allowed is 10.

Valid for: Graphs. Note: sfdp, fdp, neato only

dimen : int, default: 2, minimum: 2

Set the number of dimensions used for rendering.

The maximum value allowed is 10.

If both dimen and dim are set, the latter specifies the dimension used for layout, and the former for rendering. If only dimen is set, this is used for both layout and rendering dimensions.

Note that, at present, all aspects of rendering are 2D. This includes the shape and size of nodes, overlap removal, and edge routing. Thus, for dimen > 2, the only valid information is the pos attribute of the nodes.

All other coordinates will be 2D and, at best, will reflect a projection of a higher-dimensional point onto the plane.

Valid for: Graphs. Note: sfdp, fdp, neato only

dir : dirType, default: forward(directed), none(undirected)

Edge type for drawing arrowheads.

Indicates which ends of the edge should be decorated with an arrowhead.

The actual style of the arrowhead can be specified using the arrowhead and arrowtail attributes.

See limitation.

Valid for: Edges.

diredgeconstraints : string|bool, default: false

If true, constraints are generated for each edge in the largest (heuristic) directed acyclic subgraph such that the edge must point downwards.

Only valid when mode="ipsep".

If hier, generates level constraints similar to those used with mode="hier". The main difference is that, in the latter case, only these constraints are involved, so a faster solver can be used.

Valid for: Graphs. Note: neato only

distortion : double, default: 0.0, minimum: -100.0

Distortion factor for shape=polygon.

Positive values cause top part to be larger than bottom; negative values do the opposite.

Valid for: Nodes.

dpi : double, default: 96.0, 0.0

Specifies the expected number of pixels per inch on a display device.

For bitmap output, dpi guarantees that text rendering will be done more accurately, both in size and in placement.

For SVG output, dpi guarantees the dimensions in the output correspond to the correct number of points or inches.

Valid for: Graphs. Note: svg, bitmap output only

edgehref : escString, default: ""

Synonym for edgeURL.

Valid for: Edges. Note: svg, map only

edgetarget : escString, default: <none>

If the edge has a URL or edgeURL attribute, edgetarget determines which window of the browser is used for the URL attached to the non-label part of the edge.

Setting edgetarget=_graphviz will open a new window if it doesn’t already exist, or reuse it if it does.

If undefined, the value of the target is used instead.

Valid for: Edges. Note: svg, map only

edgetooltip : escString, default: ""

Tooltip annotation attached to the non-label part of an edge.

Valid for: Edges. Note: svg, cmap only

edgeURL : escString, default: ""

The link for the non-label parts of an edge.

edgeURL overrides any URL defined for the edge.

Also, edgeURL is used near the head or tail node unless overridden by headURL or tailURL, respectively.

See limitation.

Valid for: Edges. Note: svg, map only

epsilon : double, default: .0001 * # nodes(mode == KK), .0001(mode == major), .01(mode == sgd)

Terminating condition. If the length squared of all energy gradients are less than epsilon, the algorithm stops.

Valid for: Graphs. Note: neato only

esep : addDouble|addPoint, default: +3

Margin used around polygons for purposes of spline edge routing.

The interpretation is the same as given for sep. esep should normally be strictly less than sep.

Valid for: Graphs. Note: not dot

fillcolor : color|colorList, default: lightgrey(nodes), black(clusters)

Color used to fill the background of a node or cluster assuming style=filled, or a filled arrowhead.

If fillcolor is not defined, color is used. (For clusters, if color is not defined, bgcolor is used.) If this is not defined, the default is used, except for shape=point or when the output format is MIF, which use black by default.

If the value is a colorList, a gradient fill is used. By default, this is a linear fill; setting style=radial will cause a radial fill. At present, only two colors are used. If the second color (after a colon) is missing, the default color is used for it.

See also the gradientangle attribute for setting the gradient angle.

Note that a cluster inherits the root graph’s attributes if defined. Thus, if the root graph has defined a fillcolor, this will override a color or bgcolor attribute set for the cluster.

Valid for: Clusters, Edges, Nodes.

fixedsize : bool|string, default: false

If false, the size of a node is determined by smallest width and height needed to contain its label and image, if any, with a margin specified by the margin attribute.

The width and height must also be at least as large as the sizes specified by the width and height attributes, which specify the minimum values for these parameters.

If true, the node size is specified by the values of the width and height attributes only and is not expanded to contain the text label. There will be a warning if the label (with margin) cannot fit within these limits.

If the fixedsize attribute is set to shape, the width and height attributes also determine the size of the node shape, but the label can be much larger. Both the label and shape sizes are used when avoiding node overlap, but all edges to the node ignore the label and only contact the node shape. No warning is given if the label is too large.

Valid for: Nodes.

fontcolor : color, default: black

Color used for text.

Valid for: Clusters, Edges, Graphs, Nodes.

fontname : string, default: "Times-Roman"

Font used for text. This very much depends on the output format and, for non-bitmap output such as PostScript or SVG, the availability of the font when the graph is displayed or printed. As such, it is best to rely on font faces that are generally available, such as Times-Roman, Helvetica or Courier.

How font names are resolved also depends on the underlying library that handles font name resolution. If Graphviz was built using the fontconfig library, the latter library will be used to search for the font. See the commands fc-list, fc-match and the other fontconfig commands for how names are resolved and which fonts are available. Other systems may provide their own font package, such as Quartz for OS X.

Note that various font attributes, such as weight and slant, can be built into the font name. Unfortunately, the syntax varies depending on which font system is dominant. Thus, using fontname="times bold italic" will produce a bold, slanted Times font using Pango, the usual main font library. Alternatively, fontname="times:italic" will produce a slanted Times font from fontconfig, while fontname="times-bold" will resolve to a bold Times using Quartz. You will need to ascertain which package is used by your Graphviz system and refer to the relevant documentation.

If Graphviz is not built with a high-level font library, fontname will be considered the name of a Type 1 or True Type font file. If you specify fontname=schlbk, the tool will look for a file named schlbk.ttf or schlbk.pfa or schlbk.pfb in one of the directories specified by the fontpath attribute. The lookup does support various aliases for the common fonts.

Valid for: Clusters, Edges, Graphs, Nodes.

fontnames : string, default: ""

Allows user control of how basic fontnames are represented in SVG output.

If fontnames is undefined or svg, the output will try to use known SVG fontnames.

For example, the default font Times-Roman will be mapped to the basic SVG font serif. This can be overridden by setting fontnames to ps or hd. In the former case, known PostScript font names such as Times-Roman will be used in the output. In the latter case, the fontconfig font conventions are used. Thus, Times-Roman would be treated as Nimbus Roman No9 L. These last two options are useful with SVG viewers that support these richer fontname spaces.

Valid for: Graphs. Note: svg only

fontpath : string, default: system-dependent

Directory list used by libgd to search for bitmap fonts if Graphviz was not built with the fontconfig library.

If fontpath is not set, the environment variable DOTFONTPATH is checked.

If DOTFONTPATH is not set, GDFONTPATH is checked.

If GDFONTPATH not set, libgd uses its compiled-in font path.

Note that fontpath is an attribute of the root graph.

Valid for: Graphs.

fontsize : double, default: 14.0, minimum: 1.0

Font size, in points, used for text.

Valid for: Clusters, Edges, Graphs, Nodes.

forcelabels : bool, default: true

If true, all xlabel attributes are placed, even if there is some overlap with nodes or other labels.

Valid for: Graphs.

gradientangle : int, default: ""

If a gradient fill is being used, this determines the angle of the fill.

For linear fills, the colors transform along a line specified by the angle and the center of the object. For radial fills, a value of zero causes the colors to transform radially from the center; for non-zero values, the colors transform from a point near the object’s periphery as specified by the value.

If unset, the default angle is 0.

Valid for: Clusters, Graphs, Nodes.

group : string, default: ""

If the end points of an edge belong to the same group, i.e., have the same group attribute, parameters are set to avoid crossings and keep the edges straight.

Valid for: Nodes. Note: dot only

head_lp : point

Position of an edge’s head label, in points. The position indicates the center of the label.

Valid for: Edges. Note: write only

headclip : bool, default: true

If true, the head of an edge is clipped to the boundary of the head node; otherwise, the end of the edge goes to the center of the node, or the center of a port, if applicable.

Valid for: Edges.

headhref : escString, default: ""

Synonym for headURL.

Valid for: Edges. Note: svg, map only

headlabel : lblString, default: ""

Text label to be placed near head of edge.

See limitation.

Valid for: Edges.

headport : portPos, default: center

Indicates where on the head node to attach the head of the edge. In the default case, the edge is aimed towards the center of the node, and then clipped at the node boundary.

See limitation.

Valid for: Edges.

headtarget : escString, default: <none>

If the edge has a headURL, headtarget determines which window of the browser is used for the URL. Setting headURL=_graphviz will open a new window if the window doesn’t already exist, or reuse the window if it does.

If undefined, the value of the target is used.

Valid for: Edges. Note: svg, map only

headtooltip : escString, default: ""

Tooltip annotation attached to the head of an edge.

Used only if the edge has a headURL attribute.

Valid for: Edges. Note: svg, cmap only

headURL : escString, default: ""

If defined, headURL is output as part of the head label of the edge.

Also, this value is used near the head node, overriding any URL value.

See limitation.

Valid for: Edges. Note: svg, map only

height : double, default: 0.5, minimum: 0.02

Height of node, in inches.

This is taken as the initial, minimum height of the node. If fixedsize is true, this will be the final height of the node. Otherwise, if the node label requires more height to fit, the node’s height will be increased to contain the label.

If the output format is dot, the value given to height will be the final value.

If the node shape is regular, the width and height are made identical:

If both the width and the height are set explicitly, the maximum of the two values is used.
If one of width or height is set explicitly, that value is used for both width and height.
If neither is set explicitly, the minimum of the two default values is used.

Valid for: Nodes.

href : escString, default: ""

Synonym for URL.

Valid for: Clusters, Edges, Graphs, Nodes. Note: svg, postscript, map only

id : escString, default: ""

Allows the graph author to provide an identifier for graph objects which is to be included in the output.

Normal \N, \E, \G substitutions are applied.

If provided, it is the responsibility of the provider to keep id values unique for its intended downstream use.

Note, in particular, that \E does not provide a unique id for multi-edges.

If no id attribute is provided, then a unique internal id is used. However, this value is unpredictable by the graph writer.

If the graph provides an id attribute, this will be used as a prefix for internally generated attributes. By making internally-used attributes distinct, the user can include multiple image maps in the same document.

Valid for: Clusters, Edges, Graphs, Nodes. Note: svg, postscript, map only

image : string, default: ""

Gives the name of a file containing an image to be displayed inside a node. The image file must be in one of the recognized formats, typically JPEG, PNG, GIF, BMP, SVG, or Postscript, and be able to be converted into the desired output format.

The file must contain the image size information:

Bitmap formats usually already contain image size.
PostScript files must contain a line starting with %%BoundingBox: followed by four integers specifying the lower left x and y coordinates and the upper right x and y coordinates of the bounding box for the image, the coordinates being in points.
An SVG image file must contain width and height attributes, typically as part of the svg element. The values for these should have the form of a floating point number, followed by optional units, e.g., width="76pt". Recognized units are in, px, pc, pt, cm and mm for inches, pixels, picas, points, centimeters and millimeters, respectively. The default unit is points.

Unlike with the shapefile attribute, the image is treated as node content rather than the entire node. In particular, an image can be contained in a node of any shape, not just a rectangle.

Valid for: Nodes.

imagepath : string, default: ""

Specifies a list of directories in which to look for image files as specified by the image attribute or using the IMG element in HTML-like labels.

imagepath should be a list of (absolute or relative) pathnames, each separated by a semicolon ; (for Windows) or a colon : (all other OS).

The first directory in which a file of the given name is found will be used to load the image.

If imagepath is not set, relative pathnames for the image file will be interpreted with respect to the current working directory.

Valid for: Graphs.

imagepos : string, default: "mc"

Controls how an image is positioned within its containing node.

imagepos only has an effect when the image is smaller than the containing node.

The default is to be centered both horizontally and vertically.

Valid values:

tl - Top Left
tc - Top Centered
tr - Top Right
ml - Middle Left
mc - Middle Centered (the default)
mr - Middle Right
bl - Bottom Left
bc - Bottom Centered
br - Bottom Right

Valid for: Nodes.

imagescale : bool|string, default: false

Controls how an image fills its containing node.

In general, the image is given its natural size, (cf. dpi), and the node size is made large enough to contain its image, its label, its margin, and its peripheries.

Its width and height will also be at least as large as its minimum width and height. If, however, fixedsize=true, the width and height attributes specify the exact size of the node.

During rendering, in the default case (imagescale=false), the image retains its natural size.
If imagescale=true, the image is uniformly scaled (i.e., its aspect ratio is preserved) to fit inside the node. At least one dimension of the image will be as large as possible given the size of the node.
When imagescale=width, the width of the image is scaled to fill the node width.
The corresponding property holds when imagescale=height.
When imagescale=both, both the height and the width are scaled separately to fill the node.

In all cases, if a dimension of the image is larger than the corresponding dimension of the node, that dimension of the image is scaled down to fit the node.

As with the case of expansion, if imagescale=true, width and height are scaled uniformly.

Valid for: Nodes.

inputscale : double, default: <none>

For layout algorithms that support initial input positions (specified by the pos attribute), this attribute can be used to appropriately scale the values.

By default, fdp and neato interpret the x and y values of pos as being in inches. (NOTE: neato -n(2) treats the coordinates as being in points, being the unit used by the layout algorithms for the pos attribute.) Thus, if the graph has pos attributes in points, one should set inputscale=72. This can also be set on the command line using the -s flag flag.

If unset, no scaling is done and the units on input are treated as inches.

inputscale=0 is equivalent to inputscale=72.

Valid for: Graphs. Note: fdp, neato only

K : double, default: 0.3, minimum: 0

Spring constant used in virtual physical model. It roughly corresponds to an ideal edge length (in inches), in that increasing K tends to increase the distance between nodes.

Note that the edge attribute len can be used to override this value for adjacent nodes.

Valid for: Clusters, Graphs. Note: sfdp, fdp only

label : lblString, default: "\N" (nodes), "" (otherwise)

Text label attached to objects.

If a node’s shape is record, then the label can have a special format which describes the record layout.

Note that a node’s default label is "\N", so the node’s name or ID becomes its label.

Technically, a node’s name can be an HTML string but this will not mean that the node’s label will be interpreted as an HTML-like label. This is because the node’s actual label is an ordinary string, which will be replaced by the raw bytes stored in the node’s name.

To get an HTML-like label, the label attribute value itself must be an HTML string.

Valid for: Clusters, Edges, Graphs, Nodes.

label_scheme : int, default: 0, minimum: 0

Whether to treat a node whose name has the form |edgelabel|* as a special node representing an edge label.

The default, label_scheme=0, produces no effect.
If label_scheme=1, sfdp uses a penalty-based method to make that kind of node close to the center of its neighbor.
With label_scheme=2, sfdp uses a penalty-based method to make that kind of node close to the old center of its neighbor.
Finally, label_scheme=3 invokes a two-step process of overlap removal and straightening.

Valid for: Graphs. Note: sfdp only

labelangle : double, default: -25.0, minimum: -180.0

Determines, along with labeldistance, where the headlabel / taillabel are placed with respect to the head / tail in polar coordinates.

The origin in the coordinate system is the point where the edge touches the node. The ray of 0 degrees goes from the origin back along the edge, parallel to the edge at the origin.

The angle, in degrees, specifies the rotation from the 0 degree ray, with positive angles moving counterclockwise and negative angles moving clockwise.

Valid for: Edges.

labeldistance : double, default: 1.0, minimum: 0.0

Multiplicative scaling factor adjusting the distance that the headlabel / taillabel is from the head / tail node.

The default distance is 10 points.

See labelangle for more details.

Valid for: Edges.

labelfloat : bool, default: false

If true, allows edge labels to be less constrained in position. In particular, it may appear on top of other edges.

Valid for: Edges.

labelfontcolor : color, default: black

Color used for headlabel and taillabel.

If not set, defaults to edge’s fontcolor.

Valid for: Edges.

labelfontname : string, default: "Times-Roman"

Font used for headlabel and taillabel.

If not set, defaults to edge’s fontname.

Valid for: Edges.

labelfontsize : double, default: 14.0, minimum: 1.0

Font size, in points, used for headlabel and taillabel.

If not set, defaults to edge’s fontsize.

Valid for: Edges.

labelhref : escString, default: ""

Synonym for labelURL.

Valid for: Edges. Note: svg, map only

labeljust : string, default: "c"

Justification for cluster labels.

If labeljust=r, the label is right-justified within bounding rectangle
If labeljust=l, left-justified
Else the label is centered.

Note that a subgraph inherits attributes from its parent. Thus, if the root graph sets labeljust=l, the subgraph inherits this value.

Valid for: Clusters, Graphs.

labelloc : string, default: "t"(clusters), "b"(root graphs), "c"(nodes)

Vertical placement of labels for nodes, root graphs and clusters.

For graphs and clusters, only labelloc=t and labelloc=b are allowed, corresponding to placement at the top and bottom, respectively.

By default, root graph labels go on the bottom and cluster labels go on the top.

Note that a subgraph inherits attributes from its parent. Thus, if the root graph sets labelloc=b, the subgraph inherits this value.

For nodes, this attribute is used only when the height of the node is larger than the height of its label.

If labelloc=t, labelloc=c, labelloc=b, the label is aligned with the top, centered, or aligned with the bottom of the node, respectively.

By default, the label is vertically centered.

Valid for: Clusters, Graphs, Nodes.

labeltarget : escString, default: <none>

If the edge has a URL or labelURL attribute, this attribute determines which window of the browser is used for the URL attached to the label.

Setting labeltarget=_graphviz will open a new window if it doesn’t already exist, or reuse it if it does.

If undefined, the value of the target is used.

Valid for: Edges. Note: svg, map only

labeltooltip : escString, default: ""

Tooltip annotation attached to label of an edge.

Valid for: Edges. Note: svg, cmap only

labelURL : escString, default: ""

If defined, labelURL is the link used for the label of an edge.

labelURL overrides any URL defined for the edge.

Valid for: Edges. Note: svg, map only

landscape : bool, default: false

If true, the graph is rendered in landscape mode. Synonymous with rotate=90 or orientation=landscape.

Valid for: Graphs.

layer : layerRange, default: ""

Specifies layers in which the node, edge or cluster is present.

Valid for: Clusters, Edges, Nodes.

layerlistsep : string, default: ","

Specifies the separator characters used to split an attribute of type layerRange into a list of ranges.

Valid for: Graphs.

layers : layerList, default: ""

Specifies a linearly ordered list of layer names attached to the graph

The graph is then output in separate layers. Only those components belonging to the current output layer appear.

See How to use drawing layers (overlays).

Valid for: Graphs.

layerselect : layerRange, default: ""

Selects a list of layers to be emitted.

Valid for: Graphs.

layersep : string, default: ":\t "

Specifies the separator characters used to split the layers attribute into a list of layer names.

Valid for: Graphs.

layout : string, default: ""

Specifies the name of the layout algorithm to use, such as dot or neato.

Normally, graphs should be kept independent of a type of layout. In some cases, however, it can be convenient to embed the type of layout desired within the graph.

For example, a graph containing position information from a layout might want to record what the associated layout algorithm was.

This attribute takes precedence over the -K flag or the actual command name used.

Valid for: Graphs.

len : double, default: 1.0(neato), 0.3(fdp)

Preferred edge length, in inches.

Valid for: Edges. Note: fdp, neato only

levels : int, default: MAXINT, minimum: 0.0

Number of levels allowed in the multilevel scheme.

Valid for: Graphs. Note: sfdp only

levelsgap : double, default: 0.0

Specifies strictness of level constraints in neato when mode="ipsep" or mode=hier.

Larger positive values mean stricter constraints, which demand more separation between levels. On the other hand, negative values will relax the constraints by allowing some overlap between the levels.

Valid for: Graphs. Note: neato only

lhead : string, default: ""

Logical head of an edge.

When compound is true, if lhead is defined and is the name of a cluster containing the real head, the edge is clipped to the boundary of the cluster.

See limitation.

Valid for: Edges. Note: dot only

lheight : double

Height of graph or cluster label, in inches.

Valid for: Clusters, Graphs. Note: write only

lp : point

Label position, in points.

The position indicates the center of the label.

Valid for: Clusters, Edges, Graphs. Note: write only

ltail : string, default: ""

Logical tail of an edge.

When compound=true, if ltail is defined and is the name of a cluster containing the real tail, the edge is clipped to the boundary of the cluster.

See limitation.

Valid for: Edges. Note: dot only

lwidth : double

Width of graph or cluster label, in inches.

Valid for: Clusters, Graphs. Note: write only

margin : double|point, default: <device-dependent>

For graphs, this sets x and y margins of canvas, in inches.

If the margin is a single double, both margins are set equal to the given value.

Note that the margin is not part of the drawing but just empty space left around the drawing. The margin basically corresponds to a translation of drawing, as would be necessary to center a drawing on a page. Nothing is actually drawn in the margin. To actually extend the background of a drawing, see the pad attribute.

For clusters, margin specifies the space between the nodes in the cluster and the cluster bounding box. By default, this is 8 points.

For nodes, this attribute specifies space left around the node’s label. By default, the value is 0.11,0.055.

Valid for: Clusters, Graphs, Nodes.

maxiter : int, default: 100 * # nodes(mode == KK), 200(mode == major), 30(mode == sgd), 600(fdp)

Sets the number of iterations used.

Valid for: Graphs. Note: fdp, neato only

mclimit : double, default: 1.0

Multiplicative scale factor used to alter the MinQuit (default = 8) and MaxIter (default = 24) parameters used during crossing minimization.

These correspond to the number of tries without improvement before quitting and the maximum number of iterations in each pass.

Valid for: Graphs. Note: dot only

mindist : double, default: 1.0, minimum: 0.0

Specifies the minimum separation between all nodes.

Valid for: Graphs. Note: circo only

minlen : int, default: 1, minimum: 0

Minimum edge length (rank difference between head and tail).

Valid for: Edges. Note: dot only

mode : string, default: major

Technique for optimizing the layout.

For neato, if mode="major", neato uses stress majorization.
If mode="KK", neato uses a version of the gradient descent method. KK is sometimes appreciably faster for small (number of nodes < 100) graphs. A significant disadvantage is that KK may cycle.
If mode="sgd", neato uses a version of the stochastic gradient descent method. sgd’s advantage is faster and more reliable convergence than both the previous methods, while sgd’s disadvantage is that it runs in a fixed number of iterations and may require larger values of maxiter in some graphs.

There are two experimental modes in neato:

mode="hier", which adds a top-down directionality similar to the layout used in dot, and
mode="ipsep", which allows the graph to specify minimum vertical and horizontal distances between nodes. (See the sep attribute.)

For sfdp, the default is mode="spring", which corresponds to using a spring-electrical model. Setting mode="maxent" causes a similar model to be run but one that also takes into account edge lengths specified by the len attribute.

Valid for: Graphs. Note: neato only

model : string, default: shortpath

Specifies how the distance matrix is computed for the input graph.

The distance matrix specifies the ideal distance between every pair of nodes. neato attemps to find a layout which best achieves these distances. By default, it uses the length of the shortest path, where the length of each edge is given by its len attribute.

If model="circuit", neato uses the circuit resistance model to compute the distances. This tends to emphasize clusters.
If model="subset", neato uses the subset model. This sets the edge length to be the number of nodes that are neighbors of exactly one of the end points, and then calculates the shortest paths. This helps to separate nodes with high degree.

For more control of distances, one can use model=mds. In this case, the len of an edge is used as the ideal distance between its vertices.

A shortest path calculation is only used for pairs of nodes not connected by an edge. Thus, by supplying a complete graph, the input can specify all of the relevant distances.

Valid for: Graphs. Note: neato only

mosek : bool, default: false

If Graphviz is built with MOSEK defined, mode=ipsep and mosek=true, the Mosek software is use to solve the ipsep constraints.

Valid for: Graphs. Note: neato only

newrank : bool, default: false

Whether to use a single global ranking, ignoring clusters.

The original ranking algorithm in dot is recursive on clusters. This can produce fewer ranks and a more compact layout, but sometimes at the cost of a head node being place on a higher rank than the tail node. It also assumes that a node is not constrained in separate, incompatible subgraphs. For example, a node cannot be in a cluster and also be constrained by rank=same with a node not in the cluster.

This allows nodes to be subject to multiple constraints. Rank constraints will usually take precedence over edge constraints.

Valid for: Graphs. Note: dot only

nodesep : double, default: 0.25, minimum: 0.02

In dot, nodesep specifies the minimum space between two adjacent nodes in the same rank, in inches.

For other layouts, nodesep affects the spacing between loops on a single node, or multiedges between a pair of nodes.

Valid for: Graphs.

nojustify : bool, default: false

By default, the justification of multi-line labels is done within the largest context that makes sense. Thus, in the label of a polygonal node, a left-justified line will align with the left side of the node (shifted by the prescribed margin). In record nodes, left-justified line will line up with the left side of the enclosing column of fields. If nojustify=true, multi-line labels will be justified in the context of itself.

For example, if nojustify is set, the first label line is long, and the second is shorter and left-justified, the second will align with the left-most character in the first line, regardless of how large the node might be.

Valid for: Clusters, Edges, Graphs, Nodes.

normalize : double|bool, default: false

Normalizes coordinates of final layout so that the first point is at the origin, and then rotates the layout so that the angle of the first edge is specified by the value of normalize in degrees.

If normalize is not a number, it is evaluated as a bool, with true corresponding to 0 degrees.

NOTE: Since the attribute is evaluated first as a number, 0 and 1 cannot be used for false and true.

Valid for: Graphs. Note: not dot

notranslate : bool, default: false

By default, the final layout is translated so that the lower-left corner of the bounding box is at the origin.

This can be annoying if some nodes are pinned or if the user runs neato -n.

To avoid this translation, set notranslate=true.

Valid for: Graphs. Note: neato only

nslimit : double

Sets number of iterations in network simplex applications.

nslimit is used in computing node x coordinates.

If defined, # iterations = nslimit * # nodes; otherwise, # iterations = MAXINT.

Valid for: Graphs. Note: dot only

nslimit1 : double

Sets number of iterations in network simplex applications.

nslimit1 is used for ranking nodes.

If defined, # iterations = nslimit * # nodes; otherwise, # iterations = MAXINT.

Valid for: Graphs. Note: dot only

ordering : string, default: ""

If ordering="out", then the outedges of a node, that is, edges with the node as its tail node, must appear left-to-right in the same order in which they are defined in the input.

If ordering="in", then the inedges of a node must appear left-to-right in the same order in which they are defined in the input.

If defined as a graph or subgraph attribute, the value is applied to all nodes in the graph or subgraph.

Note that the graph attribute takes precedence over the node attribute.

Valid for: Graphs, Nodes. Note: dot only

orientation : double|string, default: 0.0, "", minimum: 360.0

When used on nodes: Angle, in degrees, to rotate polygon node shapes. For any number of polygon sides, 0 degrees rotation results in a flat base.

When used on graphs: If "[lL]*", sets graph orientation to landscape.

Used only if rotate is not defined.

Valid for: Graphs, Nodes.

outputorder : outputMode, default: breadthfirst

Specify order in which nodes and edges are drawn.

Valid for: Graphs.

overlap : string|bool, default: true

Determines if and how node overlaps should be removed.

Nodes are first enlarged using the sep attribute. If true , overlaps are retained. If the value is "scale", overlaps are removed by uniformly scaling in x and y. If the value converts to "false", and it is available, Prism, a proximity graph-based algorithm, is used to remove node overlaps. This can also be invoked explicitly with overlap=prism. This technique starts with a small scaling up, controlled by the overlap_scaling attribute, which can remove a significant portion of the overlap. The prism option also accepts an optional non-negative integer suffix. This can be used to control the number of attempts made at overlap removal. By default, overlap="prism" is equivalent to overlap="prism1000". Setting overlap="prism0" causes only the scaling phase to be run.

If Prism is not available, or the version of Graphviz is earlier than 2.28, "overlap=false" uses a Voronoi-based technique. This can always be invoked explicitly with "overlap=voronoi".

If overlap="scalexy", x and y are separately scaled to remove overlaps.

If overlay="compress", the layout will be scaled down as much as possible without introducing any overlaps, obviously assuming there are none to begin with.

N.B.The remaining allowed values of overlap correspond to algorithms which, at present, can produce bad aspect ratios. In addition, we deprecate the use of the "ortho*" and "portho*".

If the value is "vpsc", overlap removal is done as a quadratic optimization to minimize node displacement while removing node overlaps.

If the value is "orthoxy" or "orthoyx", overlaps are moved by optimizing two constraint problems, one for the x axis and one for the y. The suffix indicates which axis is processed first. If the value is “ortho”, the technique is similar to “orthoxy” except a heuristic is used to reduce the bias between the two passes. If the value is "ortho_yx", the technique is the same as "ortho", except the roles of x and y are reversed. The values "portho", "porthoxy", "porthoxy", and "portho_yx" are similar to the previous four, except only pseudo-orthogonal ordering is enforced.

If the layout is done by neato with mode="ipsep", then one can use overlap=ipsep. In this case, the overlap removal constraints are incorporated into the layout algorithm itself. N.B. At present, this only supports one level of clustering.

Except for fdp and sfdp, the layouts assume overlap="true" as the default. Fdp first uses a number of passes using a built-in, force-directed technique to try to remove overlaps. Thus, fdp accepts overlap with an integer prefix followed by a colon, specifying the number of tries. If there is no prefix, no initial tries will be performed. If there is nothing following a colon, none of the above methods will be attempted. By default, fdp uses overlap="9:prism". Note that overlap="true", overlap="0:true" and overlap="0:" all turn off all overlap removal.

By default, sfdp uses overlap="prism0".

Except for the Voronoi and prism methods, all of these transforms preserve the orthogonal ordering of the original layout. That is, if the x coordinates of two nodes are originally the same, they will remain the same, and if the x coordinate of one node is originally less than the x coordinate of another, this relation will still hold in the transformed layout. The similar properties hold for the y coordinates. This is not quite true for the "porth*" cases. For these, orthogonal ordering is only preserved among nodes related by an edge.

Valid for: Graphs. Note: not dot

overlap_scaling : double, default: -4, minimum: -1.0e10

When overlap=prism, the layout is scaled by this factor, thereby removing a fair amount of node overlap, and making node overlap removal faster and better able to retain the graph’s shape.

If overlap_scaling is negative, the layout is scaled by -1*overlap_scaling times the average label size.
If overlap_scaling is positive, the layout is scaled by overlap_scaling.
If overlap_scaling is zero, no scaling is done.

Valid for: Graphs. Note: prism only

overlap_shrink : bool, default: true

Whether the overlap removal algorithm should perform a compression pass to reduce the size of the layout.

Valid for: Graphs. Note: prism only

pack : bool|int, default: false

Whether each connected component of the graph should be laid out separately, and then the graphs packed together.

If pack has an integral value, this is used as the size, in points,of a margin around each part; otherwise, a default margin of 8 is used.

If pack is interpreted as false, the entire graph is laid out together. The granularity and method of packing is influenced by the packmode attribute.

For layouts which always do packing, such as twopi, the pack attribute is just used to set the margin.

pack is treated as true if the value of pack is true (case-insensitive) or a non-negative integer.

Valid for: Graphs.

packmode : packMode, default: node

This indicates how connected components should be packed (cf. packMode). Note that defining packmode will automatically turn on packing as though one had set pack=true.

Valid for: Graphs.

pad : double|point, default: 0.0555 (4 points)

Specifies how much, in inches, to extend the drawing area around the minimal area needed to draw the graph.

If pad is a single double, both the x and y pad values are set equal to the given value. This area is part of the drawing and will be filled with the background color, if appropriate.

Normally, a small pad is used for aesthetic reasons, especially when a background color is used, to avoid having nodes and edges abutting the boundary of the drawn region.

Valid for: Graphs.

page : double|point

Width and height of output pages, in inches.

If only a single value is given, this is used for both the width and height.

If page is set and is smaller than the size of the layout, a rectangular array of pages of the specified page size is overlaid on the layout, with origins aligned in the lower-left corner, thereby partitioning the layout into pages. The pages are then produced one at a time, in pagedir order.

At present, page only works for PostScript output. For other types of output, use another tool to split the output into multiple output files, or use viewport to generate multiple files.

Valid for: Graphs.

pagedir : pagedir, default: BL

The order in which pages are emitted.

Used only if page is set and applicable.

Limited to one of the 8 row or column major orders.

Valid for: Graphs.

pencolor : color, default: black

Color used to draw the bounding box around a cluster.

If pencolor is not defined, color is used.

If color is not defined, bgcolor is used.

If bgcolor is not defined, the default is used.

Note that a cluster inherits the root graph’s attributes if defined. Thus, if the root graph has defined a pencolor, this will override a color or bgcolor attribute set for the cluster.

Valid for: Clusters.

penwidth : double, default: 1.0, minimum: 0.0

Specifies the width of the pen, in points, used to draw lines and curves, including the boundaries of edges and clusters.

penwidth value is inherited by subclusters, and has no effect on text.

Previous to 31 January 2008, the effect of penwidth=W was achieved by including setlinewidth(W) as part of a style specification.

If both attributes are set, penwidth will be used.

Valid for: Clusters, Edges, Nodes.

peripheries : int, default: shape default(nodes), 1(clusters), minimum: 0

Set number of peripheries used in polygonal shapes and cluster boundaries.

Note that user-defined shapes are treated as a form of box shape, so the default peripheries value is 1 and the user-defined shape will be drawn in a bounding rectangle. Setting peripheries=0 will turn this off.

peripheries=1 is the maximum value for clusters.

Valid for: Clusters, Nodes.

pin : bool, default: false

Keeps the node at the node’s given input position.

If true and the node has a pos attribute on input, neato or fdp prevents the node from moving from the input position. This property can also be specified in the pos attribute itself (cf. the point type).

Note: Due to an artifact of the implementation, previous to 27 Feb 2014, final coordinates are translated to the origin. Thus, if you look at the output coordinates given in the (x)dot or plain format, pinned nodes will not have the same output coordinates as were given on input. If this is important, a simple workaround is to maintain the coordinates of a pinned node. The vector difference between the old and new coordinates will give the translation, which can then be subtracted from all of the appropriate coordinates.

After 27 Feb 2014, this translation can be avoided in neato by setting notranslate=true. However, if the graph specifies node overlap removal or a change in aspect ratio, node coordinates may still change.

Valid for: Nodes. Note: fdp, neato only

pos : point|splineType

Position of node, or spline control points.

For nodes, the position indicates the center of the node. On output, the coordinates are in points.

In neato and fdp, pos can be used to set the initial position of a node. By default, the coordinates are assumed to be in inches. However, the -s command line flag can be used to specify different units. As the output coordinates are in points, feeding the output of a graph laid out by a Graphviz program into neato or fdp will almost always require the -s flag.

When the -n command line flag is used with neato, it is assumed the positions have been set by one of the layout programs, and are therefore in points. Thus, neato -n can accept input correctly without requiring a -s flag and, in fact, ignores any such flag.

Valid for: Edges, Nodes.

quadtree : quadType|bool, default: normal

Quadtree scheme to use.

quadtree=true aliases quadtree=normal
quadtree=false aliases quadtree=none
quadtree=2 aliases quadtree=fast

Valid for: Graphs. Note: sfdp only

quantum : double, default: 0.0, minimum: 0.0

If quantum > 0.0, node label dimensions will be rounded to integral multiples of the quantum.

Valid for: Graphs.

rank : rankType, default:

Rank constraints on the nodes in a subgraph.

If rank="same", all nodes are placed on the same rank.
If rank="min", all nodes are placed on the minimum rank.
If rank="source", all nodes are placed on the minimum rank, and the only nodes on the minimum rank belong to some subgraph with rank="source" or rank="min".

Analogous criteria hold for rank="max" and rank="sink".

(Note: the minimum rank is topmost or leftmost, and the maximum rank is bottommost or rightmost.)

Valid for: . Note: dot only

rankdir : rankdir, default: TB

Sets direction of graph layout.

For example, if rankdir="LR", and barring cycles, an edge T -> H; will go from left to right. By default, graphs are laid out from top to bottom.

This attribute also has a side-effect in determining how record nodes are interpreted. See record shapes.

Valid for: Graphs. Note: dot only

ranksep : double|doubleList, default: 0.5(dot), 1.0(twopi), minimum: 0.02

In dot, sets the desired rank separation, in inches.

This is the minimum vertical distance between the bottom of the nodes in one rank and the tops of nodes in the next. If the value contains equally, the centers of all ranks are spaced equally apart. Note that both settings are possible, e.g., ranksep="1.2 equally".

In twopi, this attribute specifies the radial separation of concentric circles. For twopi, ranksep can also be a list of doubles. The first double specifies the radius of the inner circle; the second double specifies the increase in radius from the first circle to the second; etc. If there are more circles than numbers, the last number is used as the increment for the remainder.

Valid for: Graphs. Note: twopi, dot only

ratio : double|string

Sets the aspect ratio (drawing height/drawing width) for the drawing.

Note that this is adjusted before the size attribute constraints are enforced.

In addition, the calculations usually ignore the node sizes, so the final drawing size may only approximate what is desired.

If ratio is numeric, ratio is taken as the desired aspect ratio. Then, if the actual aspect ratio is less than the desired ratio, the drawing height is scaled up to achieve the desired ratio; if the actual ratio is greater than that desired ratio, the drawing width is scaled up.

If ratio="fill" and the size attribute is set, node positions are scaled, separately in both x and y, so that the final drawing exactly fills the specified size. If both size values exceed the width and height of the drawing, then both coordinate values of each node are scaled up accordingly. However, if either size dimension is smaller than the corresponding dimension in the drawing, one dimension is scaled up so that the final drawing has the same aspect ratio as specified by size. Then, when rendered, the layout will be scaled down uniformly in both dimensions to fit the given size, which may cause nodes and text to shrink as well. This may not be what the user wants, but it avoids the hard problem of how to reposition the nodes in an acceptable fashion to reduce the drawing size.

If ratio="compress" and the size attribute is set, dot attempts to compress the initial layout to fit in the given size. This achieves a tighter packing of nodes but reduces the balance and symmetry. This feature only works in dot.

If ratio="expand", the size attribute is set, and both the width and the height of the graph are less than the value in size, node positions are scaled uniformly until at least one dimension fits size exactly. Note that this is distinct from using size as the desired size, as here the drawing is expanded before edges are generated and all node and text sizes remain unchanged.

If ratio="auto", the page attribute is set and the graph cannot be drawn on a single page, then size is set to an “ideal” value.

In particular, the size in a given dimension will be the smallest integral multiple of the page size in that dimension which is at least half the current size. The two dimensions are then scaled independently to the new size. This feature only works in dot.

Valid for: Graphs.

rects : rect

Rectangles for fields of records, in points.

Valid for: Nodes. Note: write only

regular : bool, default: false

If true, force polygon to be regular, i.e., the vertices of the polygon will lie on a circle whose center is the center of the node.

Valid for: Nodes.

remincross : bool, default: true

If true and there are multiple clusters, run crossing minimization a second time.

Valid for: Graphs. Note: dot only

repulsiveforce : double, default: 1.0, minimum: 0.0

The power of the repulsive force used in an extended Fruchterman-Reingold force directed model. Values larger than 1 tend to reduce the warping effect at the expense of less clustering.

Valid for: Graphs. Note: sfdp only

resolution : double, default: 96.0, 0.0

Synonym for dpi.

Valid for: Graphs. Note: svg, bitmap output only

root : string|bool, default: <none>(graphs), false(nodes)

Specifies nodes to be used as the center of the layout and the root of the generated spanning tree.

As a graph attribute, this gives the name of the node.
As a node attribute, it specifies that the node should be used as a central node.

In twopi, root will actually be the central node. In circo, the block containing the node will be central in the drawing of its connected component. If not defined, twopi will pick a most central node, and circo will pick a random node.

If the root attribute is defined as the empty string, twopi will reset it to name of the node picked as the root node.

For twopi, it is possible to have multiple roots, presumably one for each component. If more than one node in a component is marked as the root, twopi will pick one.

Valid for: Graphs, Nodes. Note: circo, twopi only

rotate : int, default: 0

If rotate=90, sets drawing orientation to landscape.

Valid for: Graphs.

rotation : double, default: 0

Rotates the final layout counter-clockwise by the specified number of degrees.

Valid for: Graphs. Note: sfdp only

samehead : string, default: ""

Edges with the same head and the same samehead value are aimed at the same point on the head.

This has no effect on loops.

Each node can have at most 5 unique samehead values.

See limitation.

Attribute Type Descriptions

The following list gives the legal strings corresponding to values of the given types. The syntax for describing legal type strings is a mixture of literal strings, stdio encodings (e.g., %f for a double), and regular expressions. For regular expressions, (...)* indicates 0 or more copies of the expression enclosed in the parentheses, (...)+ indicates 1 or more, and (...)? denotes 0 or 1 copy.

addDouble

A double with an optional prefix '+'.

Attributes: esep, sep

addPoint

A point with an optional prefix '+'.

Attributes: esep, sep

arrowType

"normal"		"inv"
"dot"		"invdot"
"odot"		"invodot"
"none"		"tee"
"empty"		"invempty"
"diamond"		"odiamond"
"ediamond"		"crow"
"box"		"obox"
"open"		"halfopen"
"vee"

The examples above show a set of commonly used arrow shapes. There is a grammar of arrow shapes which can be used to describe a collection of 3,111,696 arrow combinations of the 42 variations of the primitive set of 11 arrows.

The basic arrows shown above contain:

most of the primitive shapes (box, crow, diamond, dot, inv, none, normal, tee, vee)
shapes that can be derived from the grammar (odot, invdot, invodot, obox, odiamond)
shapes supported as special cases for backward-compatibility (ediamond, open, halfopen, empty, invempty).

Attributes: arrowhead, arrowtail

clusterMode

"local"
"global"
"none"

Attributes: clusterrank

color

Colors can be specified using one of four formats:

`"#%2x%2x%2x"`	Red-Green-Blue (RGB)
`"#%2x%2x%2x%2x"`	Red-Green-Blue-Alpha (RGBA)
`"H[, ]+S[, ]+V"`	Hue-Saturation-Value (HSV) 0.0 <= H,S,V <= 1.0
string	color name

The specification for the RGB and RGBA formats are the format strings used by sscanf to scan the color value. Thus, these values have the form “#RGB” or “#RGBA”, where R, G, B, and A each consist of 2 hexadecimal digits, and can be separated by whitespace. HSV colors have the form of 3 numbers between 0 and 1, separated by whitespace or commas.

String-valued color specifications are case-insensitive and interpreted in the context of the current color scheme, as specified by the colorscheme attribute. If this is undefined, the X11 naming scheme will be used. An initial "/" character can be used to override the use of the colorscheme attribute. In particular, a single initial "/" will cause the string to be evaluated using the default X11 naming. If the color value has the form "/ssss/yyyy", the name yyyy is interpreted using the schema ssss. If the color scheme name is empty, i.e., the color has the form "//yyyy", the colorscheme attribute is used. Thus, the forms "yyyy" and "//yyyy" are equivalent.

At present, Graphviz recognizes the default color scheme X11, and the Brewer color schemes (cf. ColorBrewer). Please note that Brewer color schemes are covered by this license.

Examples:

Color	RGB	HSV	String
White	"#ffffff"	"0.000 0.000 1.000"	"white"
Black	"#000000"	"0.000 0.000 0.000"	"black"
Red	"#ff0000"	"0.000 1.000 1.000"	"red"
Turquoise	"#40e0d0"	"0.482 0.714 0.878"	"turquoise"
Sienna	"#a0522d"	"0.051 0.718 0.627"	"sienna"

The string value transparent can be used to indicate no color. This is only available in the output formats ps, svg, fig, vmrl, and the bitmap formats. It can be used whenever a color is needed but is most useful with the bgcolor attribute. Usually, the same effect can be achieved by setting style to invis.

Attributes: bgcolor, color, fillcolor, fontcolor, labelfontcolor, pencolor

colorList

A colon-separated list of weighted color values: WC(:WC)* where each WC has the form C(;F)? with C a color value and the optional F a floating-point number, 0 ≤ F ≤ 1. The sum of the floating-point numbers in a colorList must sum to at most 1.

NOTE: Gradient fills, described below, are currently only available via *CAIRO or SVG rendering.

If the colorList value specifies multiple colors, with no weights, and a filled style is specified, a linear gradient fill is done using the first two colors. If weights are present, a degenerate linear gradient fill is done. This essentially does a fill using two colors, with the weights specifying how much of region is filled with each color. If the style attribute contains the value radial, then a radial gradient fill is done. These fills work with any shape.

For certain shapes, the style attribute can be set to do fills using more than 2 colors. See the style type for more information.

The following table shows some variations of the yellow:blue color list depending on the style and gradientangle attributes.

Gradient angle	`style=filled`	`style=filled fillcolor=yellow;0.3:blue`	`style=radial`
0
45
90
180
270
360

Attributes: bgcolor, color, fillcolor

dirType

For an edge T -> H;

"forward"

"back"

"both"

"none"

That is, a glyph is drawn at the head end of an edge if and only if dirType is "forward" or "both"; a glyph is drawn at the tail end of an edge if and only if dirType is "back" or "both";

For undirected edges T -- H;, one of the nodes, usually the righthand one, is treated as the head for the purpose of interpreting "forward" and "back".

Attributes: dir

double

Double-precision floating point number.

Attributes: area, arrowsize, Damping, defaultdist, distortion, dpi, epsilon, fontsize, height, inputscale, K, labelangle, labeldistance, labelfontsize, len, levelsgap, lheight, lwidth, margin, mclimit, mindist, nodesep, normalize, nslimit, nslimit1, orientation, overlap_scaling, pad, page, penwidth, quantum, ranksep, ratio, repulsiveforce, resolution, rotation, scale, size, skew, voro_margin, weight, width, z

doubleList

A colon-separated list of doubles: "%f(:%f)*" where each %f is a double.

Attributes: ranksep

escString

A string allowing escape sequences which are replaced according to the context. For node attributes, the substring "\N" is replaced by the name of the node, and the substring "\G" by the name of the graph. For graph or cluster attributes, the substring "\G" is replaced by the name of the graph or cluster. For edge attributes, the substring "\E" is replaced by the name of the edge, the substring "\G" is replaced by the name of the graph or cluster, and the substrings "\T" and "\H" by the names of the tail and head nodes, respectively. The name of an edge is the string formed from the name of the tail node, the appropriate edge operator ("--" or "->") and the name of the head node. In all cases, the substring "\L" is replaced by the object’s label attribute.

In addition, if the associated attribute is label, headlabel or taillabel, the escape sequences "\n", "\l" and "\r" divide the label into lines, centered, left-justified, and right-justified, respectively.

Obviously, one can use \\ to get a single backslash. A backslash appearing before any character not listed above is ignored.

Attributes: edgehref, edgetarget, edgetooltip, edgeURL, headhref, headtarget, headtooltip, headURL, href, id, labelhref, labeltarget, labeltooltip, labelURL, tailhref, tailtarget, tailtooltip, tailURL, target, tooltip, URL

int

Integer number.

Attributes: dim, dimen, gradientangle, label_scheme, levels, maxiter, minlen, pack, peripheries, rotate, samplepoints, searchsize, showboxes, sides, sortv, weight

layerList

list of strings separated by characters from the layersep attribute (by default, colons, tabs or spaces), defining layer names and implicitly numbered 1,2,…

Attributes: layers

layerRange

specifies a list of layers defined by the layers attribute.

It consists of a list of layer intervals separated by any collection of characters from the layerlistsep attribute. Each layer interval is specified as either a layerId or a layerIdslayerId, where layerId = "all", a decimal integer or a layer name. (An integer i corresponds to layer i, layers being numbered from 1.)

The string s consists of 1 or more separator characters specified by the layersep attribute.

Thus, assuming the default values for layersep and layerlistsep, if layers="a:b:c:d:e:f:g:h", the layerRange string layers="a:b,d,f:all" would denote the layers a b d f g h.

Attributes: layer, layerselect

lblString

An escString or an HTML label.

Attributes: headlabel, label, taillabel, xlabel

outputMode

"breadthfirst"
"nodesfirst"
"edgesfirst"

These specify the order in which nodes and edges are drawn in concrete output.

The default "breadthfirst" is the simplest, but when the graph layout does not avoid edge-node overlap, this mode will sometimes have edges drawn over nodes and sometimes on top of nodes.
If the mode "nodesfirst" is chosen, all nodes are drawn first, followed by the edges. This guarantees an edge-node overlap will not be mistaken for an edge ending at a node.
On the other hand, usually for aesthetic reasons, it may be desirable that all edges appear beneath nodes, even if the resulting drawing is ambiguous. This can be achieved by choosing "edgesfirst".

Attributes: outputorder

packMode

"node"
"clust"
"graph"
"array(_flags)?(%d)?"

The modes "node", "clust" or "graph" specify that the components should be packed together tightly, using the specified granularity. A value of "node" causes packing at the node and edge level, with no overlapping of these objects. This produces a layout with the least area, but it also allows interleaving, where a node of one component may lie between two nodes in another component. A value of "graph" does a packing using the bounding box of the component. Thus, there will be a rectangular region around a component free of elements of any other component. A value of “clust” guarantees that top-level clusters are kept intact. What effect a value has also depends on the layout algorithm. For example, neato does not support clusters, so a value of "clust" will have the same effect as the default "node" value.

The mode "array(_flag)?(%d)?" indicates that the components should be packed at the graph level into an array of graphs. By default, the components are in row-major order, with the number of columns roughly the square root of the number of components. If the optional flags contains 'c', then column-major order is used. Finally, if the optional integer suffix is used, this specifies the number of columns for row-major or the number of rows for column-major. Thus, the mode "array_c4" indicates array packing, with 4 rows, starting in the upper left and going down the first column, then down the second column, etc., until all components are used.

If a graph is smaller than the array cell it occupies, it is centered by default. The optional flags may contain 't', 'b', 'l', or 'r', indicating that the graphs should be aligned along the top, bottom, left or right, respectively.

If the optional flags contains 'u', this causes the insertion order of elements in the array to be determined by user-supplied values. Each component can specify its sort value by a non-negative integer using the sortv attribute. Components are inserted in order, starting with the one with the smallest sort value. If no sort value is specified, zero is used.

Attributes: packmode

pagedir

"BL"
"BR"
"TL"
"TR"
"RB"
"RT"
"LB"
"LT"

These specify the 8 row or column major orders for traversing a rectangular array, the first character corresponding to the major order and the second to the minor order. Thus, for “BL”, the major order is from bottom to top, and the minor order is from left to right. This means the bottom row is traversed first, from left to right, then the next row up, from left to right, and so on, until the topmost row is traversed.

Attributes: pagedir

point

"%f,%f('!')?" representing the point (x,y). The optional '!' indicates the node position should not change (input-only).

If dim=3, point may also have the format "%f,%f,%f('!')?" to represent the point (x,y,z).

Attributes: head_lp, lp, margin, pad, page, pos, scale, size, tail_lp, xlp

pointList

A list of points, separated by spaces.

Attributes: vertices

portPos

modifier indicating where on a node an edge should be aimed. It has the form portname(:compass_point)? or compass_point. If the first form is used, the corresponding node must either have record shape with one of its fields having the given portname, or have an HTML-like label, one of whose components has a PORT attribute set to portname.

If a compass point is used, it must have the form "n","ne","e","se","s","sw","w","nw","c","_". This modifies the edge placement to aim for the corresponding compass point on the port or, in the second form where no portname is supplied, on the node itself. The compass point “c” specifies the center of the node or port. The compass point "_" specifies that an appropriate side of the port adjacent to the exterior of the node should be used, if such exists. Otherwise, the center is used. If no compass point is used with a portname, the default value is "_".

This attribute can be attached to an edge using the headport and tailport attributes, or as part of the edge description as in

node1:port1 -> node2:port5:nw;

Note that it is legal to have a portname the same as one of the compass points. In this case, this reference will be resolved to the port. Thus, if node A has a port w, then headport=w will refer to the port and not the compass point. At present, in this case, there is no way to specify that the compass point should be used.

Attributes: headport, tailport

quadType

"normal"
"fast"
"none".

Using "fast" gives about a 2-4 times overall speedup compared with "normal", though layout quality can suffer a little.

Attributes: quadtree

rankdir

"TB"
"LR"
"BT"
"RL"

Corresponding to directed graphs drawn from top to bottom, from left to right, from bottom to top, and from right to left, respectively.

Attributes: rankdir

rankType

"same"
"min"
"source"
"max"
"sink"

Attributes: rank

rect

"%f,%f,%f,%f"

The rectangle llx,lly,urx,ury gives the coordinates, in points, of the lower-left corner (llx,lly) and the upper-right corner (urx,ury).

Attributes: bb, rects

shape

A string specifying the shape of a node. There are three main types of shapes:

The record-based shape has largely been superseded and greatly generalized by HTML-like labels. That is, instead of using shape=record, consider using shape=none and an HTML-like label.

Attributes: shape

smoothType

Values are:

"none"
"avg_dist"
"graph_dist"
"power_dist"
"rng",
"spring"
"triangle"

Attributes: smoothing

splineType

spline ( ';' spline )*

where spline = (endp)? (startp)? point (triple)+
and triple = point point point
and endp = "e,%f,%f"
and startp = "s,%f,%f"

If a spline has points p₁ p₂ p₃ … pₙ, (n = 1 (mod 3)), the points correspond to the control points of a cubic B-spline from p₁ to pₙ. If startp is given, it touches one node of the edge, and the arrowhead goes from p₁ to startp. If startp is not given, p₁ touches a node. Similarly for pₙ and endp.

Attributes: pos

startType

has the syntax (style)?(seed)?.

If style is present, it must be one of the strings "regular", "self", or "random". In the first case, the nodes are placed regularly about a circle. In the second case, an abbreviated version of neato is run to obtain the initial layout. In the last case, the nodes are placed randomly in a unit square.

If seed is present, it specifies a seed for the random number generator. If seed is a positive number, this is used as the seed. If it is anything else, the current time, and possibly the process id, is used to pick a seed, thereby making the choice more random. In this case, the seed value is stored in the graph.

If the value is just "random", a time-based seed is chosen.

Note that input positions, specified by a node’s pos attribute, are only used when the style is "random".

Attributes: start

string

Text; a sequence of characters.

Attributes: _background, charset, class, colorscheme, comment, diredgeconstraints, fixedsize, fontname, fontnames, fontpath, group, image, imagepath, imagepos, imagescale, labelfontname, labeljust, labelloc, layerlistsep, layersep, layout, lhead, ltail, mode, model, ordering, orientation, overlap, ratio, root, samehead, sametail, shapefile, splines, stylesheet, target, xdotversion

style

styleItem ( ',' styleItem )*

where styleItem	=	name or name'('args')'
and args	=	name ( ',' name )*

and name can be any string of characters not containing a space, a left or right parenthesis, or a comma. Whitespace characters are ignored.

NOTE: The styles tapered, striped and wedged are only available in release 2.30 and later.

The recognized style names are,

For nodes and edges:

"dashed"
"dotted"
"solid"
"invis"
"bold"

For edges only:

"tapered"

For nodes only:

"filled"
"striped"
"wedged"
"diagonals"
"rounded"

For clusters:

"filled"
"striped"
"rounded"

The style "radial" is recognized for nodes, clusters and graphs, and indicates a radial-style gradient fill if applicable.

The style "striped" causes the fill to be done as a set of vertical stripes. The colors are specified via a colorList, the colors drawn from left to right in list order. Optional color weights can be specified to indicate the proportional widths of the bars. If the sum of the weights is less than 1, the remainder is divided evenly among the colors with no weight. Note: The style "striped" is only supported with clusters and rectangularly-shaped nodes.

The style "wedged" causes the fill to be done as a set of wedges. The colors are specified via a colorList, with the colors drawn counter-clockwise starting at angle 0. Optional color weights are interpreted analogously to the striped case described above. Note: The style "wedged" is allowed only for elliptically-shaped nodes.

The following tables illustrate some of the effects of the style settings. Examples of tapered line styles are given below. Examples of linear and radial gradient fill can be seen under colorList.

Basic style settings for nodes
`solid`	`dashed`	`dotted`
`bold`	`rounded`	`diagonals`
`filled`	`striped`	`wedged`

Basic style settings for edges
`solid`		`dashed`
`dotted`		`bold`

Basic style settings for clusters
`solid`		`dashed`		`dotted`		`bold`
`rounded`		`filled`		`striped`

The effect of style=tapered depends on the penwidth, dir, arrowhead and arrowtail attributes. The edge starts with width penwidth and tapers to width 1, in points. The dir attribute determines whether the tapering goes from tail to head (dir=forward), from head to tail (dir=forward), from the middle to both the head and tail (dir=both), or no tapering at all (dir=none). If the dir is not explicitly set, the default for the graph type is used (see dir). Arrowheads and arrowtails are also drawn, based on the value of dir; to avoid this, set arrowhead and/or arrowtail to "none".

Note: At present, the tapered style only allows a simple filled polygon. Additional styles such as dotted or dashed, or multiple colors supplied via a colorList are ignored.

The following table illustrates the style=tapered with penwidth=7 and arrowtail=none.

`dir` \ `arrowhead`	`normal`	`none`
`forward`
`back`
`both`
`none`

Additional styles are available in device-dependent form. Style lists are passed to device drivers, which can use this to generate appropriate output.

The style attribute affects the basic appearance of nodes, edges and graphs, but has no effect on any text used in labels. For this, use the fontname, fontsize and fontcolor attributes, or the <FONT>, <B>, <I>, etc. elements in HTML-like labels.

The setlinewidth style value can be used for more control over the width of node borders and edges than is allowed by bold. This style value takes an argument, specifying the width of the line in points. For example, style="bold" is equivalent to style="setlinewidth(2)". The use of setlinewidth is deprecated; one should use the penwidth attribute instead.

Attributes: style

viewPort

"%lf,%lf,%lf,%lf,%lf" or "%lf,%lf,%lf,'%s'"

The viewPort W,H,Z,x,y or W,H,Z,N specifies a viewport for the final image. The pair (W,H) gives the dimensions (width and height) of the final image, in points.

The optional Z is the zoom factor, i.e., the image in the original layout will be W/Z by H/Z points in size. By default, Z is 1.

The optional last part is either a pair (x,y) giving a position in the original layout of the graph, in points, of the center of the viewport, or the name N of a node whose center should used as the focus.

By default, the focus is the center of the graph bounding box, i.e., (bbx/2,bby/2), where "bbx,bby" is the value of the bounding box attribute bb.

Sample values: 50,50,.5,'2.8 BSD' or 100,100,2,450,300. The first will take the 100x100 point square centered on the node 2.8 BSD and scale it down by 0.5, yielding a 50x50 point final image.

Attributes: viewport


splines=none splines=""	splines=line splines=false

splines=polyline	splines=curved

splines=ortho	splines=spline splines=true