Package 'Rgraphviz'

Title: Provides plotting capabilities for R graph objects
Description: Interfaces R with the AT and T graphviz library for plotting R graph objects from the graph package.
Authors: Kasper Daniel Hansen [cre, aut], Jeff Gentry [aut], Li Long [aut], Robert Gentleman [aut], Seth Falcon [aut], Florian Hahne [aut], Deepayan Sarkar [aut]
Maintainer: Kasper Daniel Hansen <[email protected]>
License: EPL
Version: 2.51.0
Built: 2024-11-14 05:47:03 UTC
Source: https://github.com/bioc/Rgraphviz

Help Index


Class "AgEdge": A class to describe an edge for a Ragraph object

Description

This class is used to represent edges for the Ragraph class. One can retrieve various pieces of information as well as draw them.

Objects from the Class

Objects can be created by calls of the form new("AgEdge", ...).

Slots

arrowhead:

Object of class "character" The style of arrowhead for this edge.

arrowsize:

Object of class "character" A scale factor for the length of the arrow heads & tails

arrowtail:

Object of class "character" The style of arrowtail for this edge.

color:

Object of class "character" The edge color.

dir:

Object of class "character" The edge direction.

ep:

Object of class "xyPoint" The end point of the edge.

head:

Object of class "character" The head node for this edge.

lty:

Object of class "character" The edge line type.

lwd:

Object of class "numeric" The edge line width.

sp:

Object of class "xyPoint" The starting point of the edge.

splines:

Object of class "list" A list of BezierCurve objects

tail:

Object of class "character" The tail node for this edge.

txtLabel:

Object of class "character" The edge text label.

Methods

splines

Returns the splines slot

sp

Returns the sp slot

ep

Returns the ep slot

numSplines

Returns the number of splines

getSpline

Convenience method to retrieve a specific spline

show

Displays a concise description of the object

lines

Draws the edge

head

Gets the head slot

tail

Gets the tail slot

txtLabel

Returns any label for this edge

arrowhead

Retrieves the arrowhead slot.

arrowtail

Retrieves the arrowtail slot.

arrowsize

Retrieves the arrowsize slot.

Author(s)

Jeff Gentry

See Also

Ragraph, BezierCurve, xyPoint

Examples

V <- letters[1:10]
M <- 1:4
g1 <- randomGraph(V, M, .2)
z <- agopen(g1,name="foo")
x <- AgEdge(z)  ## list of AgEdge objects

vv <- x[[1]]
vv
## Demonstrate the methods of this class
splines(vv)
sp(vv)
ep(vv)
numSplines(vv)
getSpline(vv, 1)
head(vv)
tail(vv)
txtLabel(vv)
arrowhead(vv)
arrowtail(vv)
arrowsize(vv)

Class "AgNode": A class to describe a node for a Ragraph object

Description

This class is used to represent nodes for the Ragraph class. One can retrieve various pieces of information as well as draw them.

Objects from the Class

Objects can be created by calls of the form new("AgNode", ...).

Slots

center:

Object of class "xyPoint": The center point of the node

name:

Object of class "character": The name of the node, used to reference it

txtLabel:

Object of class "AgTextLabel": Label for this edge

height:

Object of class "integer": Height of the node in points

rWidth:

Object of class "integer": The right half of the node in points.

lWidth:

Object of class "integer": The left half of the node in points.

color:

Object of class "character": The drawing color of the node.

fillcolor:

Object of class "character": The color to fill in the node with.

shape:

Object of class "character": The shape of the node.

style:

Object of class "character": The style of the node.

Methods

color

signature(object = "AgNode"): Retrieves the drawing color for the node.

fillcolor

signature(object = "AgNode"): Retrieves the color to fill in the node image with.

getNodeCenter

signature(object = "AgNode"): Returns the center point of the node.

getNodeXY

signature(object = "AgNode"): Returns the center as a two element list, with the first element containing the 'x' value and the second element containing the 'y' value.

getNodeHeight

signature(object = "AgNode"): Returns the height of the node.

getNodeLW

signature(object = "AgNode"): Returns the left width of the node.

getNodeRW

signature(object = "AgNode"): Returns the right width of the node.

name

signature(object = "AgNode"): Retrieves the name of the node.

shape

signature(object = "AgNode"): Returns the shape of the node.

style

signature(object = "AgNode"): Returns the style of the node.

txtLabel

signature(object = "AgNode"): Retrieves the node label.

Author(s)

Jeff Gentry

See Also

Ragraph

Examples

V <- letters[1:10]
M <- 1:4
g1 <- randomGraph(V, M, .2)
z <- agopen(g1,name="foo")
x <- AgNode(z) ## list of AgNode objects
vv <- x[[1]]

## The methods in use
color(vv)
fillcolor(vv)
getNodeCenter(vv)
getNodeXY(vv)
getNodeHeight(vv)
getNodeLW(vv)
getNodeRW(vv)
name(vv)
shape(vv)
style(vv)
txtLabel(vv)

A function to obtain a libgraph object

Description

This function will read in a graph object and create a Ragraph object, returning it for use in other functions. The graph represented by the Ragraph can be laidout in various formats.

Usage

agopen(graph, name, nodes, edges, kind = NULL, layout = TRUE,
       layoutType = "dot",
       attrs = list(), nodeAttrs = list(), edgeAttrs = list(),
       subGList = list(), edgeMode = edgemode(graph),
       recipEdges=c("combined", "distinct"))

Arguments

graph

An object of class graphNEL

nodes

A list of pNode objects

edges

A list of pEdge objects

name

The name of the graph

kind

The type of graph

layout

Whether to layout the graph or not

layoutType

Defines the layout engine. Defaults to dot, and see graphvizCapabilities()$layoutTypes for possible values.

attrs

A list of graphviz attributes

nodeAttrs

A list of specific node attributes

edgeAttrs

A list of specific edge attributes

subGList

A list describing subgraphs for the graph parameter

edgeMode

Whether the graph is directed or undirected

recipEdges

How to handle reciprocated edges, defaults to combined

Details

graph is from the package graph-class.

The user can specify either the graph parameter and/or a combination of nodes and edges. If either of the latter parameters are not specified then graph must be passed in, and is used in the functions buildNodeList and buildEdgeList (as appropriate - if nodes is passed in but edges is not, only buildEdgeList is called) which are default transformer functions to generate the pNode and pEdge lists for layout.

The edgeMode argument specifies whether the graph is to be laid out with directed or undirected edges. This parameter defaults to the edgemode of the graph argument - note that if graph was not passed in then edgeMode must be supplied.

The kind parameter works as follows:

NULL:

Determine the direction of the graph from the graph object. This is the default and the recommended method.

AGRAPH:

An undirected graph

AGDIGRAPH:

A directed graph

AGRAPHSTRICT:

A strict undirected graph

AGDIGRAPHSTRICT:

A strict directed graph

Strict graphs do not allow self arcs or multi-edges.

If layout is set to TRUE, then the libgraph routines are used to compute the layout locations for the graph. Otherwise the graph is returned without layout information.

The subGList parameter is a list describing any subgraphs, where each element represents a subgraph and is itself a list with up to three elements. The first element, graph is required and contains the actual graph object for the subgraph. The second element, cluster is a logical value indicating if this is a cluster or a subgraph (a value of TRUE indicates a cluster, which is also the default value if this element is not specified). In Graphviz, subgraphs are more of an organizational mechanism, whereas clusters are laid out separately from the main graph and then later inserted. The last element of the list, attrs is used if there are any attributes for this subgraph. This is a named vector where the names are the attributes and the elements are the values for those attributes.

For a description of attrs, nodeAttrs and edgeAttrs, see the Ragraph man page.

The recipEdges argument can be used to specify how to handle reciprocal edges. The default value, combined will combine any reciprocated edges into a single edge (and if the graph is directed, will by default place an arrowhead on both ends of the edge), while the other option is distinct which will draw to separate edges. Note that in the case of an undirected graph, every edge of a graphNEL is going to be reciprocal due to implementation issues.

Value

An object of class Ragraph

Author(s)

Jeff Gentry

References

http://www.research.att.com/sw/tools/graphviz/

See Also

graphLayout, Ragraph, plot

Examples

set.seed(123)
V <- letters[1:10]
M <- 1:4
g1 <- randomGraph(V, M, .2)
z <- agopen(g1,name="foo")
z
z <- agopen(g1,name="foo",layoutType="neato")

A function to obtain a Ragraph object

Description

This function will read in a graphNEL object and create a Ragraph object, returning it for use in other functions. The graph represented by the Ragraph can be laidout in various formats.

Usage

agopenSimple(graph, name, kind = NULL, edgeMode=edgemode(graph),
       subGList=list(), recipEdges=c("combined", "distinct"))

Arguments

graph

An object of class graphNEL

name

The name of the Ragraph

kind

The type of graph

subGList

A list describing subgraphs for the graph parameter

edgeMode

Whether the graph is directed or undirected

recipEdges

How to handle reciprocated edges, defaults to combined, TODO: use this

Details

graph is from the package graph-class.

The edgeMode argument specifies whether the graph is to be laid out with directed or undirected edges. This parameter defaults to the edgemode of the graph argument.

The kind parameter works as follows:

NULL:

Determine the direction of the graph from the graph object. This is the default and the recommended method.

AGRAPH:

An undirected graph

AGDIGRAPH:

A directed graph

AGRAPHSTRICT:

A strict undirected graph

AGDIGRAPHSTRICT:

A strict directed graph

Strict graphs do not allow self arcs or multi-edges.

The subGList parameter is a list describing any subgraphs, where each element represents a subgraph and is itself a list with up to three elements. The first element, graph is required and contains the actual graph object for the subgraph. The second element, cluster is a logical value indicating if this is a cluster or a subgraph (a value of TRUE indicates a cluster, which is also the default value if this element is not specified). In Graphviz, subgraphs are more of an organizational mechanism, whereas clusters are laid out separately from the main graph and then later inserted. The last element of the list, attrs is used if there are any attributes for this subgraph. This is a named vector where the names are the attributes and the elements are the values for those attributes.

The recipEdges argument can be used to specify how to handle reciprocal edges. The default value, combined will combine any reciprocated edges into a single edge (and if the graph is directed, will by default place an arrowhead on both ends of the edge), while the other option is distinct which will draw to separate edges. Note that in the case of an undirected graph, every edge of a graphNEL is going to be reciprocal due to implementation issues.

Value

An object of class Ragraph

Author(s)

Li Long <[email protected]>

References

http://www.research.att.com/sw/tools/graphviz/

See Also

graphLayout, Ragraph, plot

Examples

set.seed(123)
V <- letters[1:10]
M <- 1:4
g1 <- randomGraph(V, M, .2)
z <- agopenSimple(g1,name="foo")
if(graphvizVersion()$installed_version >= "2.10") {
  ## This example will only run with Graphviz >= 2.10
  plot(z, "twopi")
}

Class "AgTextLabel": Represents a graphviz text label

Description

This class is used to represent the textlabel object in C from the Graphviz library

Objects from the Class

Objects can be created by calls of the form new("AgTextLabel", ...).

Slots

labelText:

Object of class "character" The actual label text

labelLoc:

Object of class "xyPoint" The location of the label

labelJust:

Object of class "character" The justification of the label

labelWidth:

Object of class "integer" The width of the label

labelColor:

Object of class "character" The color to print the label

labelFontsize:

Object of class "numeric" The font size for the label

Methods

labelText

Retrieves the labelText slot

labelLoc

Retrieves the labelLoc slot

labelJust

Retrieves the labelJust slot

labelWidth

Retrieves the labelWidth slot

labelColor

Retrieves the labelColor slot

labelFontsize

Retrieves the labelFontsize slot

Author(s)

Jeff Gentry

See Also

AgEdge-class, AgNode-class

Examples

V <- letters[1:10]
M <- 1:4
g1 <- randomGraph(V, M, .2)

## Make the labels be the edge weights.  This code is from the vignette
eAttrs <- list()
ew <- edgeWeights(g1)
lw <- unlist(unlist(ew))
toRemove <- removedEdges(g1)
lw <- lw[-toRemove]
names(lw) <- edgeNames(g1)
eAttrs$label <- lw

z <- agopen(g1,"foo", edgeAttrs=eAttrs)
x <- AgEdge(z)  ## list of AgEdge objects
x[[1]]  ## AgEdge
a <- txtLabel(x[[1]])
a ## txtLabel object

labelText(a)
labelLoc(a)
labelJust(a)
labelWidth(a)
labelColor(a)
labelFontsize(a)

Read / write Ragraph objects

Description

These functions will write an Ragraph object to or from a file.

Usage

agwrite(graph, filename)
agread(filename, layoutType="dot", layout=TRUE)

Arguments

graph

An object of class Ragraph

filename

The input or output filename

layoutType

character(1) specifying the format of the input file. must be one of graphvizCapabilities()$layoutTypes.

layout

logical(1) indicating whether graphLayout is to be called on the result of file input.

Details

These function are wrappers to agwrite() and agread() calls in Graphviz.

Author(s)

Jeff Gentry

See Also

agopen, agread

Examples

V <- letters[1:10]
M <- 1:4
g1 <- randomGraph(V, M, .2)
z <- agopen(g1, "foo", layout=FALSE) ## default layoutType 'dot'
file <- tempfile()
agwrite(z, file)


## supported input types
graphvizCapabilities()$layoutTypes
g2 <- agread(file, layout=TRUE)
if (interactive())
   plot(g2)

Class "BezierCurve": A class to describe a Bezier curve

Description

This class is used to represent a Bezier curve in R, which can then be used for other applications, plotted, etc

Objects from the Class

Objects can be created by calls of the form new("BezierCurve", ...).

Slots

cPoints:

Object of class "list": A list of xyPoint objects, representing control points for the curve

Methods

cPoints:

Returns the cPoints slot

pointList:

Returns a list of all points having been processed with teh getPoints method of xyPoint

bezierPoints:

Returns a matrix giving x & y points (by column) for the complete Bezier curve

lines:

Draws the Bezier curve

show:

Provides a concise display of information

Author(s)

Jeff Gentry

See Also

xyPoint

Examples

V <- letters[1:10]
M <- 1:4
g1 <- randomGraph(V, M, .2)
z <- agopen(g1,"foo")
x <- AgEdge(z)  ## list of AgEdge objects
x[[1]]  ## AgEdge
a <- splines(x[[1]])[[1]]
a  ## BezierCurve

cPoints(a)
pointList(a)
bezierPoints(a)

Class "boundingBox": A class to describe the bounding box of a Ragraph

Description

The boundingBox class is used to describe the dimensons of the bounding box for a laid out Ragraph

Objects from the Class

Objects can be created by calls of the form new("boundingBox", ...).

Slots

botLeft:

Object of class "xyPoint" Defines the bottom left point of the bounding box

upRight:

Object of class "xyPoint" Defines the upper right point of the bounding box

Methods

botLeft

Retrieve the botLeft slot

upRight

Retrieve the upRight slot

Author(s)

Jeff Gentry

See Also

Ragraph, graph-class

Examples

V <- letters[1:10]
M <- 1:4
g1 <- randomGraph(V, M, .2)
z <- agopen(g1,"foo")
x <- boundBox(z)
x

botLeft(x)
upRight(x)

A function to build lists of node and edge objects

Description

These functions can be used to generate lists of pNode and pEdge objects from an object of class graph. These lists can then be sent to Graphviz to initialize and layout the graph for plotting.

Usage

buildNodeList(graph, nodeAttrs = list(), subGList=list(), defAttrs=list())
buildEdgeList(graph, recipEdges=c("combined", "distinct"),
              edgeAttrs = list(), subGList=list(), defAttrs=list())

Arguments

graph

An object of class graph

nodeAttrs

A list of attributes for specific nodes

edgeAttrs

A list of attributes for specific edges

subGList

A list of any subgraphs to be used in Graphviz

recipEdges

How to deal with reciprocated edges

defAttrs

A list of attributes used to specify defaults.

Details

These functions will take either the nodes or the edges of the specified graph and generate a list of either pNode or pEdge objects.

The recipEdges argument can be used to specify how to handle reciprocal edges. The default value, combined will combine any reciprocated edges into a single edge (and if the graph is directed, will by default place an arrowhead on both ends of the edge), while the other option is distinct which will draw to separate edges. Note that in the case of an undirected graph, every edge of a graphNEL is going to be reciprocal due to implementation issues.

The nodeAttrs and edgeAttrs attribute lists are to be used for cases where one wants to set an attribute on a node or an edge that is not the default. In both cases, these are lists with the names of the elements corresponding to a particular attribute and the elements containing a named vector - the names of the vector are names of either node or edge objects and the values in the vector are the values for this attribute.

Note that with the edgeAttrs list, the name of the edges are in a particular format where an edge between x and y is named x~y. Note that even in an undirected graph that x~y is not the same as y~x - the name must be in the same order that the edge was defined as having.

The subGraph argument can be used to specify a list of subgraphs that one wants to use for this plot. The buildXXXList functions will determine if a particular node or edge is in one of the subgraphs and note that in the object.

The defAttrs list is a list used to specify any default values that one wishes to use. The element names corresponde to the attribute and the value is the default for that particular attribute.

If there is no default specified in defAttrs for an attribute declared in nodeAttrs or edgeAttrs, then the latter must have a value for every node or edge in the graph. Otherwise, if a default is supplied, that value is used for any node or edge not explicitly defined for a particular attribute.

Value

A list of class pNode or pEdge objects.

Author(s)

Jeff Gentry

See Also

agopen, plot.graph, pNode,pEdge

Examples

set.seed(123)
   V <- letters[1:10]
   M <- 1:4
   g1 <- randomGraph(V, M, .2)

   z <- buildEdgeList(g1)
   x <- buildNodeList(g1)

Get and set attributes for a cluster of an Ragraph object

Description

Attributes of a graph can be accessed using clusterData. There's no default attributes for clusters. The attributes must be defined using graphDataDefaults.

Usage

clusterData(self, cluster, attr)
clusterData(self, cluster, attr) <- value

Arguments

self

A Ragraph-class instance

cluster

cluster number

attr

A character vector of length one specifying the name of a cluster attribute

value

A character vector to store as the attribute value

Author(s)

Li Long <[email protected]>

Examples

g1_gz <- gzfile(system.file("GXL/graphExample-01.gxl.gz",
                            package="graph"))
g11_gz <- gzfile(system.file("GXL/graphExample-11.gxl.gz",
                             package="graph"))
if(require(XML)) {
  g1 <- fromGXL(g1_gz)
  g11 <- fromGXL(g11_gz)
  g1_11 <- join(g1, g11)
  sgl <- vector(mode="list", length=2)
  sgl[[1]] <- list(graph=g1, cluster=TRUE)
  sgl[[2]] <- list(graph=g11, cluster=TRUE)
  ng <- agopenSimple(g1_11, "tmpsg", subGList=sgl)
  clusterData(ng, 1, c("bgcolor")) <- c("blue")
  clusterData(ng, 2, c("bgcolor")) <- c("red")
  toFile(ng, layoutType="dot", filename="g1_11_dot.ps", fileType="ps")
}

Functions to generate and check global attribute lists

Description

The getDefaultAttrs function can be used to generate a default global attribute list for Graphviz. The checkAttrs function can be used to verify that such a list is valid for use.

Usage

getDefaultAttrs(curAttrs = list(), layoutType = "dot")
checkAttrs(attrs)

Arguments

curAttrs

Any attributes currently defined

layoutType

The layout method being used. Defaults to dot, and see graphvizCapabilities()$layoutTypes for possible values.

attrs

An attribute list of graphviz attributes

Details

The getDefaultAttrs function generates a four element list (elements being “graph”, “cluster”, “node” and “edge”). Contained in each is another list where the element names correspond to attributes and the value is the value for that attribute. This list can be used to set global attributes in Graphviz, and the exact list returned by getDefaultAttrs represents the values that are used as basic defaults.

The checkAttrs function can be used to verify that a global attribute list is properly formed.

Author(s)

Jeff Gentry

See Also

agopen, plot.graph

Examples

z <- getDefaultAttrs()
  checkAttrs(z)

Get and set attributes of an Ragraph object

Description

Attributes of a graph can be accessed using graphData. The attributes could be defined using graphDataDefaults.

Usage

graphData(self, attr)
graphData(self, attr) <- value

Arguments

self

A Ragraph-class instance

attr

A character vector of length one specifying the name of a graph attribute

value

A character vector to store as the attribute values

Author(s)

Li Long <[email protected]>


Get and set default attributes for an Ragraph

Description

Get/Set default values for attributes associated with a graph.

Usage

graphDataDefaults(self)
graphDataDefaults(self, attr) <- value

Arguments

self

A Ragraph-class instance

attr

A character value giving the name of the attribute

value

A character value as the default value for the specified attribute

Author(s)

Li Long <[email protected]>


A function to layout graph locations

Description

This function will take an object of class Ragraph and will perform a libgraph layout on the graph locations.

Usage

graphLayout(graph, layoutType=graph@layoutType)

Arguments

graph

An object of type Ragraph

layoutType

layout algorithm to use

Details

If the graph has already been laid out, this function merely returns its parameter. Otherwise, it will perform a libgraph layout and retrieve the appropriate location information.

Value

A laid out object of type Ragraph.

Author(s)

Jeff Gentry

See Also

agopen

Examples

V <- letters[1:10]
M <- 1:4
g1 <- randomGraph(V, M, .2)
z <- agopen(g1,"foo",layout=FALSE)
x <- z
a <- graphLayout(z)

Graph Attributes for Rgraphviz

Description

The following describes the allowable attributes to be used with Rgraphviz. Most of these are sent directly to Graphviz and will influence the plot layout, some of these are only cosmetic and stay in R. Users are referred to the Graphviz web documentation which contains some more detailed information on these attributes (and is our source).

Graph Attributes

General Graph Attributes:

bgcolor:

Color for the entire canvas. The default is to use transparent

center:

Drawing is centered in the output canvas. This is a boolean value with a default of FALSE.

fontcolor:

Color used for text, defaulting to black.

fontname:

Font used for text. Default is Times Roman.

fontpath:

Directory used to search for fonts

fontsize:

Font size, in points, for text. This attribute accepts doubles for values with a default of 14.0 and a minimum value of 1.0

label:

Label for the graph. This is a string with some extra escape sequences which can be used. 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, \G is replaced by the name of the graph or cluster. For edge attributes, the substring \N is replaced by the name of the edge, and the substrings \T and \H by the names of the tail and head nodes. The default value for nodes is \N with everything else defaulting to

labeljust:

Subgraphs inherit cluster behavior for labeljust. If r, the labels are right-justified within the bounding rectangle. If l they are left-justified. Otherwise the labels are centered. The default value is c.

labelloc:

Top/bottom placement for graph labels. A value of t places the label at the top, b places them at the bottom. By default root graph labels go on the bottom and cluster labels go on the top.

layers:

Specifies a linearly ordered list of layer names attached to the graph. Only those components belonging to the current layer appear. This attribute accepts a layerList, which is list of strings separated by the characters defined with the layersep attribute which defines layer names and implicitly numbered 1,2,etc. The default is which only uses one layer.

layersep:

Separator characters used to split the layers into a list of names. The default is colons, tabs or spaces.

margin:

Set X&Y margins of canvas in inches. Specified using the notation val,val where each val is a double.

orientation:

If "[1L*]*", set graph orientation to landscape. Used only if rotate is not defined. Default is the empty string.

page:

Width & height of output pages, in inches. If set and smaller then 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. Specified using the notion val,val where each val is a double.

pagedir:

If the page attribute is set and applicable, this attribute specifies the order in which the pages are emitted. This is limited to one of the 8 row or column major orders. One of BL, BR, TR, RB, RT, LB, or LT specifying 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). The default value is BL

quantum:

If 'quantum' > 0.0, node label dimensions will be rounded to integral multiples of the quantum. This attribute is of type double, with a default and minimum value of 0.0

ranksep:

In dot, this gives the desired rank separation in inches. If the value contains equally, the centers of all the ranks are spaced equally apart. In twopi, specifies the separation of concentric circles. This value is of type double, with a minimum value of 0.02. In dot, the default value is 0.5 and for twopi it is 1.0.

ratio:

Sets the aspect ratio for the drawing. If numeric, defines aspect ratio. If it is 'fill' and 'size' has been set, node positions are scaled such that the final drawing fills exactly the specified size. If 'compress' and the 'size' attribute is set and the graph can not be drawn on a single page, then the drawing is compressed to fit in the given size. If 'auto', the 'page' attribute is set and the graph cannot be drawn on a single page, then 'size' is set to an “ideal” value. The default for this attribute is “fill”

rotate:

If 90, set drawing orientation to landscape. This attribute accepts integer values and defaults to 0

samplepoints:

If the input graph defines the 'vertices' attribute, and output is dot or xdot, this gives the number of points used to represent circles and ellipses. It plays the same role in neato, when adjusting the layout to avoid overlapping nodes. This attribute accepts integer values and defaults to 8

size:

Maximum width and height of drawing, in inches. Specified using the notation val,val where each val is a double. If not specified and there is a current output device, the graph is scaled to fit into that device. If size is not specified and there is no current output device, a plot region of the default size will be opened and the graph scaled to match that.

start:

Parameter used to determine the initial layout of nodes. By default, nodes are randomly placed in a square whose sides have length (number of nodes). The same seed is always used for the random number generator, so the initial placement is repeatable. If 'start' converts to an integer, this is used as a seed value for the RNG. If 'start' is "regular", the nodes are placed regularly about a circle. Finally if 'start' is defined, and not one of those cases, the current time is used to pick a seed. The default is the empty string.

Dot Only Attributes

clusterrank:

Mode used for handling clusters. If "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. If the cluster has a 'label' parameter, this label is displayed w/ the cluster. Acceptable values are local, global or none - with local being the default.

compound:

Allow edges between clusters. This is a boolean value with a default of FALSE

concentrate:

Use edge concentrators. This is a boolean value with a default of FALSE

mclimit:

Scale factor used to alter the 'MinQuit' and 'MaxIter' parameters used during crossing minimization. This is a double value with a default of 1.0

nodesep:

Minimum space between two adjacent nodes of the same rank, in inches. This is a double value with a default of 0.25 and a minimum of 0.02

ordering:

If out for a graph and n is a node in G, then edges n->* appear left to right in the order that they were defined.

rankdir:

Determines if the layout is left-to-right or top-to-bottom. Acceptable values are LR and TB with the default being the latter.

remincross:

If TRUE and there are multiple clusters, run cross minimization a second time. Default is FALSE

searchsize:

During network simplex, maximum number of edges with negative cut values to search when looking for one with minimum cut value. This is an integer value with a default of 30

showboxes:

Debugging feature for postscript output, R only. Not currently implemented.

Neato Only Attributes

Damping:

Factor damping force motions. On each iteration, a node's movement is limited to this factor of its potential motion. This is a double value with a default of 0.99 and a minimum value of 0.0

defaultdist:

Default distance between nodes in separate connected components. Only applicable if pack=FALSE. Defaults to 1+(avg. len)*sqrt(|V|) and has a minimum value of epsilon.

dim:

Set the number of dimensions used for the layout. This is an integer value with a default and minimum value of 2.

epsilon:

Terminating condition. If length squared of all energy gradients are less than epsilon, the algorithm stops. This is a double value with a default of .0001 times the number of nodes.

maxiter:

Sets the number of iterations used. This is an integer value with the default of MAXINT.

model:

If circuit, use circuit resistance model to compute dissimilarity values, otherwise use shortest path. Defaults to the empty string.

Twopi Only Attributes

root:

Name of the node to use as the center of the layout. If not defined, will pick the most central node.

Not Dot Attributes

normalize:

Normalize coordinates of final layout so that the first point is at the origin, then rotate so that the first edge is horizontal. This is a boolean value with a default of FALSE.

overlap:

If scale, remove node overlaps by scaling. If FALSE, use Voronoi technique, otherwise leave overlaps. Default is the empty string.

pack:

If "true" or non-negative integer - each connected component is laid out separately and then the graphs are packed tightly. 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 'false', the entire graph is laid out together. For twopi layouts, this just sets the margin. Default is FALSE

packmode:

Indicates the granularity and method used for packing. This will automatically turn on pack. Acceptable values are node, clust and graph, specifying the granularity of packing connected components when pack=TRUE. The default is node.

sep:

Fraction to increase polygons for purposes of determining overlap. This is a double value with a default of 0.01.

splines:

Draw edges as splines. This is a boolean value with a default of TRUE.

voro_margin:

Factor to scale up drawing to allow margin for expansion in Voronoi technique. This is a double value with a default of 0.05 and a minimum value of 0.0

Output Based

resolution:

Number of pixels per inch on a display, used for SVG output. The default for this attribute is 0.96 and it accepts values of type double.

stylesheet:

A URL or pathname specifying a XML style sheet, for SVG output.

truecolor:

Output relies on a truecolor color model, used with bitmap outputs. This is a boolean value with a default of FALSE

Misc

URL:

Hyperlink incorporated into the output. For whole graphs, used as part of an image map. Not currently implemented

comment:

A device dependent commentary. Not currently implemented.

nslimit:

Number of iterations in network simplex applications. Used in computing node x coordinates

nslimit1:

Same as nslimit but for ranking nodes

outputorder:

Specify order in which nodes and edges are drawn. R only

Edge Attributes

General Edge Attributes

arrowhead:

Shape of the arrowhead. Currently somewhat limited in what can be rendered in R as opposed to what is available via Graphviz in that only open and none are allowed. The open is used by default for directed edges and none for undirected edges. R only(?)

arrowsize:

Multiplicative scale factor for arrowheads, type double. R only (?). This attribute accepts values of type double with a default of 1.0 and minimum of 1.0.

arrowtail:

Style of arrow on the tail node of an edge, see arrowhead. For directed edges that with bidirectional arrows, open is used. R only(?)

color:

The color of the edge. Defaults to black.

decorate:

If TRUE, attach edge label to edge by a 2-segment polyline, underlining the label, then going to the closest point of the spline. Default is FALSE. Currently unimplemented.

dir:

Edge type drawing, which ends should get the arrowhead. R only(?). For directed graphs, this defaults to forward and undirected graphs default to both. Other possible values are both (arrows in both directions) and back (Arrow on the tail only)

fontcolor:

The color used for text. The default value is black in R

fontname:

Font used for text. Defaults to Times Roman. Currently unimplemented.

fontsize:

Font size, used for text. Defaults to 14.0 with a minimum value of 1.0

headclip:

Head of the edge is clipped to the boundary of the head node, otherwise it goes to the center of the node. This is a boolean value with the default of TRUE. Currently unimplemented

headlabel:

Label for the head of the edge. See label in Graph Attributes for a description of additional escape sequences. Currently unimplemented.

headport:

Where on the node to aim the edges, uses center, n, s, e, nw, nw, se, and sw. The default is center.

label:

The edge label. See label in Graph Attributes for a description of additional escape sequences.

labelangle:

Angle in degrees that the label is rotated, as a double. Default is -25.0 with a minimum value of -180.0. Currently unimplemented.

labeldistance:

Multiplicative scaling factor adjusting the distance that the label is from the node. This is a double value with a default of 1.0 and a minimum value of 0.0.

layer:

Specifies the layers that this edge is present, type of layerRange. This is specified as a string in the format layerID or layerIDslayerIDslayerID..., where s is a character from the layersep attribute. The layerID attribute can be all, a decimal integer or a layer name. Defaults to the empty string.

style:

Set line style for the edge. R only. Can be one of dashed, dotted, solid, invis and bold. Defaults to solid.

tailclip:

Same as headclip except for the tail of the edge. Defaults to TRUE. Currently unimplemented.

taillabel:

Same as headlabel except for the tail of the edge. Defaults to the empty string. Currently unimplemented.

weight:

The weight of the edge. This attribute is of type double with a default of 0.75 and a minimum value of 0.01.

Dot Only Attributes

constraint:

If FALSE, edge is not used in ranking nodes. Default is TRUE.

lhead:

Logical head of an edge. If compound is TRUE, if lhead is defined and is the name of a cluster containing the real head, then the edge is clipped to the boundary of the cluster.

ltail:

Same as lhead but for the tail of the edge

minlen:

Minimum edge length (rank difference between head and tail). This is an integer value with a default of 1 and a minimum of 0.

samehead:

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

sametail:

Same as samehead but for the tail of the edge.

Neato Only Attributes

len:

Preferred edge length, in inches. This attribute accepts double values with a default of 1.0.

Misc

URL:

Hyperlink incorporated into the output. Not currently supported

headURL:

URL for the head of the edge. Not currently supported

headtooltip:

If there's a headURL, annotation for a tooltip. R only, not currently supported

tailURL:

Same as headURL but for the tail of an edge

tailtooltip:

Same as headtooltip but for the head of an edge

tooltip:

Same as headtooltip but for the edge in general

showboxes:

Debugging feature for postscript. Not currently supported

comment:

Device dependent comment inserted into the output. Not currently supported

Node Attributes

General Node Attributes

color:

Basic drawing color for the node, corresponding to the outside edge of the node. The interior of the node is specified with the fillcolor attribute. Defaults to black.

distortion:

Distortion factor for shape=polygon, positive values cause top to be larger then bottom, negative is opposite. This is a double value with a default of 0.0 and a minimum value of -100.0

fillcolor:

Background color of the node. This defaults to black.

fixedsize:

Use only width and height attributes, do not expand for the width of the label. This defaults to TRUE.

fontcolor:

Color used for text. This defaults to black.

fontname:

Font used for text. The default of this is Times Roman.

fontsize:

Size of font for the text. This defaults to 14.0 with a minimum size of 1.0.

height:

Height of the node, in inches. This attribute accepts values as doubles with a default of 0.5 and a minimum value of 0.02.

label:

Label for the node. See label in Graph Attributes for an explanation of extra escape sequences.

layer:

Layers in which the node is present. See layer in Edge Attributes for an explanation of acceptable inputs.

peripheries:

Set number of peripheries used in polygonal shapes and cluster boundaries. Note that user-defined shapes are treated as a form 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. Also, 1 is the maximum peripheries value for clusters. Not currently implemented.

pos:

Position of the node (For neato layouts, this is the initial position of the node). Specified using the notion val,val where each val is a double.

regular:

Force the polygon to be regular. Defaults to FALSE.

shape:

The shape of the node. Current acceptable values are circle, rectangle, rect, box and ellipse. The circle shape is the default. Note that box, rect and rectangle all correspond to the same actual shape.

sides:

Number of sides if shape=polygon. This is an integer value with a default value of 4 and a minimum value of 0.

skew:

Skew factor for shape=polygon. Positive values skew the polygon to the right, negative to the left. This is a double value with a default value of 0.0 and a minimum value of -100.0.

style:

Set style for the node boundary. R only. Can be one of dashed, dotted, solid, invis and bold. Defaults to solid.

width:

Width of the node, in inches. Default is 0.75 with a minimum value of 0.01

Dot Only Attributes

group:

If the end points of an edge belong to the same group, ie they have the same group attributes, parameters are set to avoid crossings and keep the edges straight

Neato Only Attributes

pin:

If TRUE and node has a pos attribute on input, neato prevents the node from moving from the input position. The default for this attribute is FALSE.

Misc

tooltip:

Annotated tooltip if URL exists. R only. Currently unsupported

toplabel:

Label near the top of nodes of shape M*. Currently unsupported

URL:

Hyperlink incorporated into the output. Not currently supported

bottomlabel:

Same as toplabel but for the bottom of the node

comment:

Device dependent comment inserted into the output. Not currently supported

shapefill:

If non-empty, if output is ps or svg and shape is 'espf', taken as a filename containing a device-dependent description of a node's shape. If non-empty for bitmap output (gif, jpg, etc), and shape set to 'custom', taken as the URL for a file containing the bitmap image for the node. For files on the local machine, the URL begins with "file://". For remote files, graphviz must have been configured to use a command such as curl to retrieve the files remotely. Currently unsupported

z:

Provides z coordinates for the node in a 3D system. Currently unsupported

details

Different attributes are appropriate for different specific graph layout algorithms. Graphviz supports three different layout algorithms, dot, neato and twopi.

There is some tension between attributes that graphviz supports and those that we can support at the R level. Please let us know if there are situations that are not being handled appropriately.

All attributes are passed down to graphviz. However they can be later modified for rendering in R.

Author(s)

Jeff Gentry

References

http://www.graphviz.org/pub/scm/graphviz2/doc/info/attrs.html

See Also

plot.graph, agopen, GraphvizLayouts


List capabilities of Graphviz

Description

List the capabilities of the installed Graphviz.

Usage

graphvizCapabilities()

Value

A list of 5 character vectors. Each character vector describes the relevant capabilitis of Graphviz.

Author(s)

Kasper Daniel Hansen [email protected]

Examples

graphvizCapabilities()

Graphviz Layout Methods

Description

The following describes the different layout methods that can be used within Rgraphviz. Each layout method has its own particular advantages and disadvantages and can have its own quirks. Currently Rgraphviz supports three different layout methods: dot, twopi and neato.

Details

Portions of the layout descriptions were taken from documents provided at http://www.research.att.com/sw/graphviz. The specific documents are listed in the references section of this page.

The dot layout

The dot algorithm produces a ranked layout of a graph honoring edge directions. It is particularly appropriate for displaying hierarchies or directed acyclic graphs. The basic layout scheme is attributed to Sugiyama et al. The specific algorithm used by dot follows the steps described by Gansner et al.

dot draws a graph in four main phases. Knowing this helps you to understand what kind of layouts dot makes and how you can control them. The layout procedure used by dot relies on the graph being acyclic. Thus, the first step is to break any cycles which occur in the input graph by reversing the internal direction of certain cyclic edges. The next step assigns nodes to discrete ranks or levels. In a top-to-bottom drawing, ranks determine Y coordinates. Edges that span more than one rank are broken into chains of virtual nodes and unit-length edges. The third step orders nodes within ranks to avoid crossings. The fourth step sets X coordnates of nodes to keep edges short, and the final step routes edge splines.

In dot, higher edge weights have the effect of causing edges to be shorter and straighter.

Fine-tuning should be approached cautiously. dot works best when it can makes a layout without much help or interference in its placement of individual nodes and edges. Layouts can be adjusted somewhat by increasing the weight of certain edges, and sometimes even by rearranging the order of nodes and edges in the file. But this can backfire because the layouts are not necessarily stable with respect to changes in the input graph. One last adjustment can invalidate all previous changes and make a very bad drawing.

The neato layout

neato is a program that makes layouts of undirected graphs following the filter model of dot. Its layout heuristic creates virtual physical models and runs an iterative solver to find low energy configurations. An ideal spring is placed between every pair of nodes such that its length is set to the shortest path distance between the endpoints. The springs push the nodes so their geometric distance in the layout approximates their path distance in the graph.

In neato, the edge weight is the strength of the corresponding spring.

As with dot, fine-tuning should be approached cautiously, as often small changes can have a drastic effect and create a poor looking layout.

The twopi layout

The radial layout algorithm represented by twopi is conceptually the simplest. It takes a node specified as the center of the layout and the root of the generated spanning tree. The remaining nodes are placed on a series of concentric circles about the center, the circle used corresponding to the graph-theoretic distance from the node to the center. Thus, for example, all of the neighbors of the center node are placed on the first circle around the center. The algorithm allocates angular slices to each branch of the induced spanning tree to guarantee enough space for the tree on each ring. It should be obvious from the description that the basic version of the twopi algorithm relies on the graph being connected.

Of great importance to the quality of the layout is the selection of an appropriate center node. By default, the twopi will randomly pick one of the nodes that are furthest from a leaf node, where a leaf node is a node of degree 1. The root attribute can be used to manually select a central node for the layout, and users are encouraged to use this attribute to select a node which provides a good quality layout. It often might not be obvious what that node will be, as it will vary from graph to graph, so some experimentation might be required.

As with dot and neato, fine-tuning should be approached cautiously, as often small changes can have a drastic effect and create a poor looking layout. The root node of the layout, as mentioned before, can have a profound effect on the outcome of the layout and care should be taken to select an appropriate one.

The circo layout

The circo layout method draws graphs using a circular layout (see Six and Tollis, GD '99 and ALENEX '99, and Kaufmann and Wiese, GD '02.) The tool identifies biconnected components and draws the nodes of the component on a circle. The block-cutpoint tree is then laid out using a recursive radial algorithm. Edge crossings within a circle are minimized by placing as many edges on the circle's perimeter as possible. In particular, if the component is outerplanar, the component will have a planar layout.

If a node belongs to multiple non-trivial biconnected components, the layout puts the node in one of them. By default, this is the first non-trivial component found in the search from the root component.

The fdp layout

The fdp layout draws undirected graphs using a spring model similar to neato. It relies on a force-directed approach in the spirit of Fruchterman and Reingold. The fdp model uses springs only between nodes connected with an edge, and an electrical repulsive force between all pairs of nodes. Also, it achieves a layout by minimizing the forces rather than the energy of the system.

Author(s)

Jeff Gentry

References

http://www.research.att.com/sw/tools/graphviz/dotguide.pdf, http://www.research.att.com/sw/tools/graphviz/neatoguide.pdf, http://www.research.att.com/sw/tools/graphviz/libguide.pdf

See Also

GraphvizAttributes, plot.graph, agopen

Examples

set.seed(123)
V <- letters[1:10]
M <- 1:4
g1 <- randomGraph(V, M, .2)
if (interactive()) {
  op <- par()
  on.exit(par=op)
  par(ask=TRUE)
  plot(g1, "dot")
  plot(g1, "neato")
  plot(g1, "twopi")
}

A function to determine graphviz library version

Description

This function will query the graphviz libraries that the package was built against and report what version of Graphviz is being used.

Usage

graphvizVersion()

Value

A list with three elements, two of class numeric_version. The first element named installed_version represents the version of Graphviz that is being used by the package. The second element named build_version represents the version of Graphviz that was used to build the package. A mismatch between these two versions may indicate problems. The third element is a logical named bundled_graphviz and indicates if Rgraphviz is using the bundled Graphviz (default) or an external Graphviz.

Author(s)

Jeff Gentry, modified by Kasper Daniel Hansen

Examples

graphvizVersion()

A function to compute layouts of graph objects

Description

This is a wrapper to layout graph objects using arbitrary layout engines. The default engine (and so far the only implemented engine) is ATT's Graphviz.

Usage

layoutGraph(x, layoutFun = layoutGraphviz, ...)

Arguments

x

A graph object

layoutFun

A function that performs the graph layout and returns a graph object with all necessary rendering information

...

Further arguments that are passed to layoutFun

Details

Layout of a graph and its rendering are two separate processes. layoutGraph provides an API to use an arbitrary algorithm for the layout. This is archived by abstraction of the layout process into a separate function (layoutFun) with well-defined inputs and outputs. The only requirements on the layoutFun are to accept a graph object as input and to return a valid graph object with all the necessary rendering information stored in its renderInfo slot. This information comprises

for nodes:

nodeX, nodeY

the locations of the nodes, in the coordinate system defined by bbox (see below).

lWidth, rWidth

the width components of the nodes, lWidth+rWidth=total width.

height

the heights of the nodes.

labelX, labelY

node label locations.

labelJust

the justification of the node labels.

label

node label text.

shape

the node shape. Valid values are box, rectangle, ellipse, plaintext, circle and triangle.

for edges:

splines

representation of the edge splines as a list of BezierCurve objects.

labelX, labelY

edge label locations.

label

edge label text.

arrowhead, arrowtail

some of Graphviz's arrow shapes are supported. Currently they are: open, normal, dot, odot, box, obox, tee, diamond, odiamond and none. In addition, a user-defined function can be passed which needs to be able to deal with 4 arguments: A list of xy coordinates for the center of the arrowhead, and the graphical parameters col, lwd and lty.

direction

The edge direction. The special value both is used when reciprocrated edges are to be collapsed.

To indicate that this information has been added to the graph, the graph plotting function should also set the laidout flag in the graphData slot to TRUE and add the bounding box information (i.e., the coordinate system in which the graph is laid out) in the format of a two-by-two matrix as item bbox in the graphData slot.

AT&T's Graphviz is the default layout algorithm to use when layoutGraph is called without a specific layoutFun function. See agopen for details about how to tweak Graphviz and the valid arguments that can be passed on through .... The most common ones to set in this context might be layoutType, which controls the type of layout to compute and the nodeAttrs and edgeAttrs arguments, which control the fine-tuning of nodes and edges.

Value

An object inheriting from class graph

Note

Please note that the layout needs to be recomputed whenever attributes are changed which are bound to affect the position of nodes or edges. This is for instance the case for the arrowhead and arrowtail parameters.

Author(s)

Florian Hahne, Deepayan Sarkar

See Also

renderGraph, graph.par, nodeRenderInfo, edgeRenderInfo, agopen,

Examples

set.seed(123)
V <- letters[1:5]
M <- 1:2
g1 <- randomGraph(V, M, 0.5)
edgemode(g1) <- "directed"
x <- layoutGraph(g1)
renderGraph(x)

## one of Graphviz's additional layout algorithms
x <- layoutGraph(g1, layoutType="neato")
renderGraph(x)

## some tweaks to Graphviz's node and edge attributes,
## including a user-defined arrowhead and node shape functions.
myArrows <- function(x, ...)
{
for(i in 1:4)
points(x,cex=i)
}

myNode <- function(x, col, fill, ...)
symbols(x=mean(x[,1]), y=mean(x[,2]), thermometers=cbind(.5, 1,
runif(1)), inches=0.5,
fg=col, bg=fill, add=TRUE)

eAtt <- list(arrowhead=c("a~b"=myArrows, "b~d"="odiamond", "d~e"="tee"))
nAtt <- list(shape=c(d="box", c="ellipse", a=myNode))
edgemode(g1) <- "directed"
x <- layoutGraph(g1, edgeAttrs=eAtt, nodeAttrs=nAtt, layoutType="neato")
renderGraph(x)

make a list of character vectors that can be used as a value for the nodeAttrs argument in agopen

Description

make a list of character vectors that can be used as a value for the nodeAttrs argument in agopen

Usage

makeNodeAttrs(g, label = nodes(g), shape = "ellipse",
              fillcolor = "#e0e0e0", ...)

Arguments

g

graph

label

character of length either 1 or numnodes(g). If the length is 1, the value is recycled.

shape

character of length either 1 or numnodes(g)

fillcolor

character of length either 1 or numnodes(g)

...

further named arguments that are character vectors of length either 1 or numNodes(g)

Details

This function is trivial but convenient.

Value

A list of named character vectors, each of which with length numNodes(g).

Author(s)

Wolfgang Huber <[email protected]>

Examples

g <- randomEGraph(letters[1:10], p=0.2)
makeNodeAttrs(g)

Class "pEdge": A class to represent an edge

Description

This class is used to represent all necessary information to plot an edge in Graphviz

Details

The attrs slot is a named list, where the names correspond to attributes and the values in the list correspond to the value for that element's attribute.

The subG slot describes which subgraph this edge is a part of. A value of 0 implies that the edge is not a member of any subgraph.

Objects from the Class

Objects can be created by calls of the form new("pEdge", ...).

Slots

from:

Object of class "character": The name of the node on the tail of this edge.

to:

Object of class "character": The name of the node on the head of this edge.

attrs:

Object of class "list": A list of attributes specific to this edge.

subG:

Object of class "integer": Which subgraph this edge is a part of.

Methods

from

signature(object = "pEdge"): Retrieves the from slot of this edge

to

signature(object = "pEdge"): Retrieves the to slot of this edge

Author(s)

R. Gentleman and Jeff Gentry

See Also

pNode, agopen, buildEdgeList

Examples

set.seed(123)
   V <- letters[1:10]
   M <- 1:4
   g1 <- randomGraph(V, M, .2)

   z <- buildEdgeList(g1)
   vv <- z[[1]]   ## Object of type pEdge

   vv
   from(vv)
   to(vv)

A function to plot pie graphs as a glyph

Description

This function allows the user to plot a pie graph at a specified x/y location in a plotting region.

Usage

pieGlyph(x, xpos, ypos, labels = names(x), edges = 200, radius = 0.8, density = NULL, angle = 45, col = NULL, border = NULL, lty = NULL, main = NULL, ...)

Arguments

xpos

The x location of the glyph

ypos

The Y location of the glyph

x

a vector of positive quantities. The values in x are displayed as the areas of pie slices.

labels

a vector of character strings giving names for the slices. For empty or NA labels, no pointing line is drawn either.

edges

the circular outline of the pie is approximated by a polygon with this many edges.

radius

the pie is drawn centered in a square box whose sides range from 1-1 to 11. If the character strings labeling the slices are long it may be necessary to use a smaller radius.

density

the density of shading lines, in lines per inch. The default value of NULL means that no shading lines are drawn. Non-positive values of density also inhibit the drawing of shading lines.

angle

the slope of shading lines, given as an angle in degrees (counter-clockwise).

col

a vector of colors to be used in filling or shading the slices. If missing a set of 6 pastel colours is used, unless density is specified when par("fg") is used.

border, lty

(possibly vectors) arguments passed to polygon which draws each slice.

main

an overall title for the plot.

...

graphical parameters can be given as arguments to pie. They will affect the main title and labels only.

Author(s)

R. Gentleman, F. Sim

See Also

pie

Examples

plot(1:10, col="white")
   pieGlyph(1:20, 5, 5)

Plot a graph object - methods

Description

A plot method for graph objects.

Usage

## S4 method for signature 'graph,ANY'
plot(x, y, ..., name = "", subGList = list(), 
    attrs = list(), nodeAttrs = list(), edgeAttrs = list(), 
    recipEdges = c("combined", "distinct"))
## S4 method for signature 'Ragraph,ANY'
plot(x, y, edgeAttrs = list(), ..., main = NULL, 
    cex.main = NULL, col.main = "black", sub = NULL, cex.sub = NULL, 
    col.sub = "black", drawNode = drawAgNode, xlab, ylab, mai)

Arguments

x

The graph object to plot

y

The layout method to use: One of dot, neato, twopi, circo, and fdp. The default is dot

name

The name of the graph, passed to agopen

subGList

A list of subgraphs taken from the primary graph object to be plotted. If provided, these subgraphs will be clustered visually. If not provided, no clusters will be used.

attrs

A list of Graphviz attributes to be sent to the layout engine

nodeAttrs

A list of attributes for specific nodes

edgeAttrs

A list of attributes for specific edges

recipEdges

Determines how to draw reciprocating edges. See agopen

main, cex.main, col.main

Main label and graphic parameters for the plot

sub, cex.sub, col.sub

Subtitle and graphic parameters for the plot

drawNode

Function to draw the nodes. The default is drawAgNode

xlab

Label for the x axis of the plot

ylab

Label for the y axis of the plot

mai

Margins for plot

...

General commands to be sent to plot

details

The first plot method in the usage section corresponds to the graph class in the graph package. It will convert the graph object into an object of class Ragraph by using Graphviz to perform the layout. Then it will call the plot method for Ragraph. The plot.graph method is nothing more then a wrapper that calls agopen and plot.Ragraph.

The second plot method in the usage section is for the Ragraph class, which describes a Graphviz structure of a graph. This method will extract necessary information from the object and use it to plot the graph.

Users can specify arbitrary drawing functions for the nodes of the Ragraph with the drawNode argument, although caution is urged. The default drawing function for all nodes is drawAgNode, which will draw a basic circle, ellipse or rectangle according to the layout specifications for each node. If supplying a custom function, users are encouraged to look at the code of this function for a more clear picture of the information required to properly draw a node. Users can specify either one custom function to be used for all nodes or a list (where length is equal to the nubmer of nodes) of functions where the Nth element in the list provides the drawing function for the Nth node, and every function will take four parameters - the first is an object of class AgNode representing the node itself and the second is an object of class xyPoint representing the upper right corner of the Graphviz plotting region (where the lower left is 0,0). The third parameter, attrs is a node attribute list and represents post-layout attribute changes where the user wants to override values present in the layout. The last argument, radConv is a divisor to the radius and is used to convert from Graphviz units to R plotting units. Outside of the first argument, the rest of these (particularly radConv which generally shouldn't be specifically set) do not need to be set by the user, but any drawing function must have them as parameters.

The attrs list requires a particular format. It must be of length 3 with names graph, node, and edge. Each of these elements themselves are lists - such that an element of graph corresponds to a graph element. A full listing of attributes and their possible settings is available at http://www.research.att.com/~erg/graphviz/info/attrs.html. All attribute values should be entered as character strings (even if the requested value is to be otherwise).

The nodeAttrs list is used to specify attributes on a particular node, instead of for all nodes. The format of this list is such that the elements correspond to attributes (the name of the element is used to note which attribute) and each element contains a named vector. The names of the vector denote which nodes are having this attribute set and the values in the vector specify the value.

The edgeAttrs list is identical in format to nodeAttrs. However, the name of the edges is in a particular format where an edge between x and y is named x~y. Note that even in an undirected graph that x~y is not the same as y~x - the name must be in the same order that the edge was defined as having.

value

The Ragraph object used for plotting

author

Jeff Gentry

seealso

graphNEL-class, graph-class

Examples

#  WHY DOES THIS NOT WORK IN CHECK?
#  V <- letters[1:10]
#  M <- 1:4
#  g1 <- randomGraph(V, M, .2)
#  plot(g1)

Class "pNode": A class to plot nodes

Description

This class is used to transfer information to Graphviz that is necessary to represent and plot a node.

Details

The attrs slot is a named list, where the names correspond to attributes and the values in the list correspond to the value for that element's attribute.

The subG slot describes which subgraph this node is a part of. A value of 0 implies that the node is not a member of any subgraph.

Objects from the Class

Objects can be created by calls of the form new("pNode", ...).

Slots

name:

Object of class "character": The name of the node, used to reference the node.

attrs:

Object of class "list": A list of attributes specific to this node.

subG:

Object of class "integer": Which subgraph this node is a part of.

Methods

name

signature(object = "pNode"): Retrieves the name slot of the object.

Author(s)

R. Gentleman and Jeff Gentry

See Also

pEdge, agopen, buildNodeList

Examples

set.seed(123)
   V <- letters[1:10]
   M <- 1:4
   g1 <- randomGraph(V, M, .2)

   z <- buildNodeList(g1)
   z[[1]]   ## Object of type pNode

   name(z[[1]])

Class "Ragraph": A class to handle libgraph representations

Description

Class Ragraph is used to handle libgraph representations of R graph objects.

Objects from the Class

Objects can be created by calls to the function agopen.

Slots

agraph:

Object of class "externalptr": A C based structure containing the libgraph information

laidout:

Object of class "logical": Whether or not this graph has been laid out or not.

layoutType:

Object of class "character": The layout method used for this object

edgemode:

Object of class "character": The edgemode for this graph - “directed” or “undirected”

AgNode:

Object of class "list": A list of AgNode objects.

AgEdge:

Object of class "list": A list of AgEdge objects.

boundBox:

Object of class "boundBox": Defines the bounding box of the plot.

bg:

Object of class "character": The background color.

fg:

Object of class "character": The foreground color.

Methods

show

signature(object = "Ragraph"): A brief summary of the contents

agraph

signature(object = "Ragraph"): Returns the external libgraph pointer

laidout

signature(object = "Ragraph"): Returns the laidout slot

boundBox

signature(object = "Ragraph"): Returns the bounding box.

AgEdge

signature(object = "Ragraph"): Returns the edge list.

AgNode

signature(object = "Ragraph"): Returns the node list.

edgemode

signature(object = "Ragraph"): Retrieves the edgemode of this object.

layoutType

signature(object = "Ragraph"): Retrieves the method used for the layout of this graph.

edgeNames

signature(object = "Ragraph"): Returns a vector of the names of the edges in this graph.

graphDataDefaults

signature(self= "Ragraph"): Gets default attributes of the given graph.

graphDataDefaults<-

signature(self= "Ragraph", attr="vector", value="vector"): Sets default attributes of the given graph.

graphData

signature(self= "Ragraph", attr="vector"): Gets attributes of the given graph.

graphData<-

signature(self= "Ragraph", attr="vector", value="vector"): Sets attributes of the given graph.

clusterData

signature(self= "Ragraph", cluster="numeric", attr="vector"): Gets attributes of a cluster for the given graph.

clusterData<-

signature(self= "Ragraph", cluster="numeric", attr="vector", value="vector"): Sets attributes of a cluster for the given graph.

edgeDataDefaults

signature(self= "Ragraph",attr="missing"): Gets default attributes of the given edge.

edgeDataDefaults<-

signature(self= "Ragraph", attr="vector", value="vector"): Sets default attributes of the given edge.

edgeData

signature(self= "Ragraph", from="vector", to="vector", attr="vector"): Gets attributes of the given edge.

edgeData<-

signature(self= "Ragraph", from="vector", to="vector", attr="vector", value="vector"): Sets attributes of the given edge.

nodeDataDefaults

signature(self= "Ragraph",attr="missing"): Gets default attributes of the given node.

nodeDataDefaults<-

signature(self= "Ragraph", attr="vector", value="vector"): Sets default attributes of the given node.

nodeData

signature(self= "Ragraph", n="vector", attr="vector"): Gets attributes of the given node.

nodeData<-

signature(self= "Ragraph", n="vector", attr="vector", value="vector"): Sets attributes of the given node.

getNodeXY

signature(object = "Ragraph"): Returns a two element list, the first element contains a numerical vector with the 'x' positions of every node in this graph, and the second element contains a numerical vector with the 'y' positions for every node in the graph.

getNodeHeight

signature(object = "Ragraph"): Returns a vector with the heights of every node in the graph

getNodeLW

signature(object = "Ragraph"): Returns a vector with the left width of every node in the graph.

getNodeRW

signature(object = "Ragraph"): Returns a vector with the right width of every node in the graph.

Author(s)

Jeff Gentry and Li Long <[email protected]>

See Also

agopen

Examples

set.seed(123)
V <- letters[1:10]
M <- 1:4
g1 <- randomGraph(V, M, .2)
z <- agopen(g1,"foo")
z

## The various methods in action

## These methods are all used to obtain positional information about nodes
getNodeXY(z)
getNodeHeight(z)
getNodeLW(z)
getNodeRW(z)

## Retrieve information about the edges in the graph
edgeNames(z)
edgemode(z)

## These get information about the layout
laidout(z)
layoutType(z)
boundBox(z)

## Used to retrieve the entire list of edges or nodes
AgEdge(z)
AgNode(z)

A Function To List Removed Edges

Description

This function can be used to retrieve a numerical vector which will describe which edges in a graph would be removed if recipEdges is set to combined during plotting.

Usage

removedEdges(graph)

Arguments

graph

An object of class graph or Ragraph, the graph to perform this operation on

Details

This function will simply detect which (if any) edges in a graph would be removed during combination of reciprocated edges.

Value

A numerical vector, where the values correspond to removed edges.

Author(s)

Jeff Gentry

See Also

edgeNames, agopen, buildEdgeList

Examples

set.seed(123)
V <- letters[1:10]
M <- 1:4
g1 <- randomGraph(V, M, .2)
removedEdges(g1)

Render a laid out graph object

Description

This method uses the renderInfo slot of a graph object to render it on a plotting device. The graph must have been laid out using the layoutGraph function before.

Usage

## S4 method for signature 'graph'
renderGraph(x, ..., drawNodes="renderNodes", drawEdges=renderEdges, graph.pars=list())

Arguments

x

An object derived from class graph

drawNodes

A function that is used for the node rendering. The details of its API are still undecided, so far the input to the function is the (laid out) graph object. Defaults to renderNodes, which is not exported in the name space (type Rgraphviz:::renderNodes to see the function definition). This default function knows how to draw node shapes of type box, rectangle, ellipse, plaintext, circle and triangle. In addition, an arbitrary user-defined function can be passed on to draw the node. This function needs to be able to deal with the following arguments: a two-by-two matrix of the bounding box for the respective node, and labelX, labelY, fill, col, lwd, lty, textCol, style, label and fontsize, which are all defined by the layout algorithm or are graphical nodeRenderInfo parameters.

drawEdges

A function that is used for the edge rendering. Defaults to renderEdges. Currently, this function can draw different types of arrowheads: open, normal, dot, odot, box, obox, tee, diamond, odiamond and none. In addition, a user-defined function can be passed as arrowhead or arrowtail parameters which needs to be able to deal with 4 arguments: A list of xy coordinates for the center of the arrowhead, and the graphical parameters col, lwd and lty.

graph.pars

A list of rendering parameters to use as defaults. Parameters that have been explicitely set using nodeRenderInfo, edgeRenderInfo or graphRenderInfo take precendence. If not explicitely supplied, the value of a call to graph.par is used. This design allows to set session-wide defaults.

...

further arguments

Details

This method can render graph objects that have previously been laid out using the function layoutGraph. The details for user defined node drawing remain to be decided.

Value

An object derived from class graph with information about the coordinates of the nodes in the coordinate system of the plotting device added to the renderInfo slot.

Author(s)

Florian Hahne

See Also

layoutGraph, link[graph:renderInfo-class]{nodeRenderInfo}, link[graph:renderInfo-class]{edgeRenderInfo}, link[graph:renderInfo-class]{graphRenderInfo},

Examples

set.seed(123)
V <- letters[1:5]
M <- 1:2
g1 <- randomGraph(V, M, 0.5)
edgemode(g1) <- "directed"
x <- layoutGraph(g1)
renderGraph(x)

## one of Graphviz's additional layout algorithms
x <- layoutGraph(g1, layoutType="neato")
renderGraph(x)

## some tweaks to Graphviz's node and edge attributes,
## including a user-defined arrowhead and node shape functions.
myArrows <- function(x, ...)
{
for(i in 1:4)
points(x,cex=i)
}

myNode <- function(x, col, fill, ...)
symbols(x=mean(x[,1]), y=mean(x[,2]), thermometers=cbind(.5, 1,
runif(1)), inches=0.5,
fg=col, bg=fill, add=TRUE)

eAtt <- list(arrowhead=c("a~b"=myArrows, "b~d"="odiamond", "d~e"="tee"))
nAtt <- list(shape=c(d="box", c="ellipse", a=myNode))
edgemode(g1) <- "directed"
x <- layoutGraph(g1, edgeAttrs=eAtt, nodeAttrs=nAtt, layoutType="neato")
renderGraph(x)

A Generic For Converting Objects To Dot

Description

This generic is used to convert objects of varying classes to the Dot language. Currently, only the graph class is supported.

Usage

toDot(graph, filename, ...)

Arguments

graph

The graph to output to Dot

filename

The name of the file to output to.

...

Any arguments to pass on to agopen

details

The method defined for graph objects is a convenience wrapper around agopen and agwrite in that order. It will take an object of class graph (or one of its subclasses), call agopen (any extra arguments besides the graph and the name parameter should be passed in via ...) and then write the resulting information via agwrite in the file specified by filename.

author

Jeff Gentry

seealso

agopen, agwrite, graph-class

Examples

set.seed(123)
  V <- letters[1:10]
  M <- 1:4
  g1 <- randomGraph(V, M, .2)

  nAttrs <- list()
  eAttrs <- list()
  nAttrs$label <- c(a="lab1", b="lab2", g="lab3", d="lab4")
  eAttrs$label <- c("a~h"="test", "c~h"="test2")
  nAttrs$color <- c(a="red", b="red", g="green", d="blue")
  eAttrs$color <- c("a~d"="blue", "c~h"="purple")

  toDot(g1, tempfile(), nodeAttrs=nAttrs, edgeAttrs=eAttrs)

Render a graph in a file with given format

Description

Render a graph in a file with given format

Usage

toFile(graph, layoutType = "dot", filename, fileType = "dot")

Arguments

graph

an instance of the Ragraph class

layoutType

Which layout algorithm to use. Defaults to dot, and see graphvizCapabilities()$layoutTypes for possible values.

filename

output file name

fileType

Output file type. Defaults to dot, and see graphvizCapabilities()$deviceTypes for possible values.

Details

This function takes a given Ragraph, does the chosen layout, then renders the output to an external file. Users could view the output file with corresponding viewer.

Value

toFile returns NULL after writing to a file.

Author(s)

Li Long <[email protected]>

References

Rgraphviz by E. Ganssner, S. North, www.graphviz.org

Examples

g1_gz <- gzfile(system.file("GXL/graphExample-01.gxl.gz",
                            package="graph"))

if(require(XML)) {
  g1 <- fromGXL(g1_gz)
  ag <- agopen(g1, name="test")

  toFile(ag, layoutType="dot", filename="g1_dot.svg", fileType="svg")
  toFile(ag, layoutType="neato", filename="g1_neato.ps", fileType="ps")
  toFile(ag, layoutType="twopi", filename="g1_twopi.svg", fileType="svg")
}

Class "xyPoint": A class to represent a X/Y coordinate.

Description

This class is used to describe a coordinate in 2-dimensional (X/Y) space

Objects from the Class

Objects can be created by calls of the form new("xyPoint", ...).

Slots

x:

Object of class "numeric" The x coordinate

y:

Object of class "numeric" The y coordinate

Methods

getX

Returns the value stored in the x slot

getY

Returns the value stored in the y slot

getPoints

Returns a vector of two numerical values representing the x and y positions

show

Display information about the object in a concise fashion

Author(s)

Jeff Gentry

Examples

z <- new("xyPoint", x=150, y=30)
   z
   getPoints(z)

   getX(z)
   getY(z)