Ubuntu Manpage: tcldot - graph manipulation in tcl

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introduction
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NAME

       tcldot - graph manipulation in tcl

SYNOPSIS

       #!/usr/local/bin/tclsh
       package require Tcldot

USAGE

       Requires the dynamic loading facilities of tcl7.6 or later.

INTRODUCTION

       tcldot  is  a tcl dynamically loaded extension that incorporates the directed graph facilities of dot(1),
       and the undirected graph facilities of neato(1), into tcl and provides a set of commands to control those
       facilities.   tcldot converts dot and neato from batch processing tools to an interpreted and, if needed,
       interactive set of graph manipulation facilities.

COMMANDS

tcldot initially adds only three commands to tcl, namely dotnew, dotread, and dotstring. These commands
return a handle for the graph that has just been created and that handle can then be used as a command
for further actions on the graph.

All other "commands" are of the form:

handle <method> parameters

Many of the methods return further handles of graphs, nodes of edges, which are themselves registered as
commands.

The methods are described in detail below, but in summary:

Graph methods are:

addedge, addnode, addsubgraph, countedges, countnodes, layout, listattributes, listedgeattributes,
listnodeattributes, listedges, listnodes, listnodesrev, listsubgraphs, render, rendergd,
queryattributes, queryedgeattributes, querynodeattributes, queryattributevalues,
queryedgeattributevalues, querynodeattributevalues, setattributes, setedgeattributes,
setnodeattributes, showname, write.

Node methods are:

addedge, listattributes, listedges, listinedges, listoutedges, queryattributes,
queryattributevalues, setattributes, showname.

Edge methods are:

delete, listattributes, listnodes, queryattributes, queryattributevalues, setattributes, showname.

dotnew graphType ?attributeName attributeValue? ?...?

creates a new empty graph and returns its graphHandle.

graphType can be any supported by dot(1) namely: "graph," "digraph," "graphstrict," or
"digraphstrict." (In digraphs edges have a direction from tail to head. "Strict" graphs or
digraphs collapse multiple edges between the same pair of nodes into a single edge.)

Following the mandatory graphType parameter the dotnew command will accept an arbitrary number of
attribute name/value pairs for the graph. Certain special graph attributes and permitted values
are described in dot(1), but the programmer can arbitrarily invent and assign values to additional
attributes beyond these. In dot the attribute name is separated from the value by an "="
character. In tcldot the "=" has been replaced by a " " (space) to be more consistent with tcl
syntax. e.g.

set g [dotnew digraph rankdir LR]

dotread fileHandle

reads in a dot-language description of a graph from a previously opened file identified by the
fileHandle. The command returns the graphHandle of the newly read graph. e.g.

set f [open test.dot r]
set g [dotread $f]

dotstring string

reads in a dot-language description of a graph from a Tcl string; The command returns the
graphHandle of the newly read graph. e.g.

set g [dotstring $dotsyntaxstring]

graphHandle addnode ?nodeName? ?attributeName attributeValue? ?...?

creates a new node in the graph whose handle is graphHandle and returns its nodeHandle. The
handle of a node is a string like: "node0" where the integer value is different for each node.
There can be an arbitrary number of attribute name/value pairs for the node. Certain special node
attributes and permitted values are described in dot(1), but the programmer can arbitrarily invent
and assign values to additional attributes beyond these. e.g.

set n [$g addnode "N" label "Top\nNode" shape triangle eggs easyover]

A possible cause of confusion in tcldot is the distinction between handles, names, labels, and
variables. The distinction is primarily in who owns them. Handles are owned by tcldot and are
guaranteed to be unique within one interpreter session. Typically handles are assigned to
variables, like "n" above, for manipulation within a tcl script. Variables are owned by the
programmer. Names are owned by the application that is using the graph, typically names are
important when reading in a graph from an external program or file. Labels are the text that is
displayed with the node (or edge) when the graph is displayed, labels are meaningful to the reader
of the graph. Only the handles and variables are essential to tcldot's ability to manipulate
abstract graphs. If a name is not specified then it defaults to the string representation of the
handle, if a label is not specified then it defaults to the name.

graphHandle addedge tailNode headNode ?attributeName attributeValue? ?...?

creates a new edge in the graph whose handle is graphHandle and returns its edgeHandle. tailNode
and headNode can be specified either by their nodeHandle or by their nodeName. e.g.

set n [$g addnode]
set m [$g addnode]
$g addedge $n $m label "NM"

$g addnode N
$g addnode M
$g addedge N M label "NM"

The argument is recognized as a handle if possible and so it is best to avoid names like "node6"
for nodes. If there is potential for conflict then use findnode to translate explicitly from
names to handles. e.g.

$g addnode "node6"
$g addnode "node99"
$g addedge [$g findnode "node6"] [$g findnode "node99"]

There can be an arbitrary number of attribute name/value pairs for the edge. Certain special edge
attributes and permitted values are described in dot(1), but the programmer can arbitrarily invent
and assign values to additional attributes beyond these.

graphHandle addsubgraph ?graphName? ?attributeName attributeValue? ?...?

creates a new subgraph in the graph and returns its graphHandle. If the graphName is omitted then
the name of the subgraph defaults to it's graphHandle. There can be an arbitrary number of
attribute name/value pairs for the subgraph. Certain special graph attributes and permitted
values are described in dot(1), but the programmer can arbitrarily invent and assign values to
additional attributes beyond these. e.g.

set sg [$g addsubgraph dinglefactor 6]

Clusters, as described in dot(1), are created by giving the subgraph a name that begins with the
string: "cluster". Cluster can be labelled by using the label attibute. e.g.

set cg [$g addsubgraph cluster_A label dongle dinglefactor 6]

nodeHandle addedge headNode ?attributeName attributeValue? ?...?

creates a new edge from the tail node identified by tha nodeHandle to the headNode which can be
specified either by nodeHandle or by nodeName (with preference to recognizing the argument as a
handle). The graph in which this is drawn is the graph in which both nodes are members. There
can be an arbitrary number of attribute name/value pairs for the edge. These edge attributes and
permitted values are described in dot(1). e.g.

[$g addnode] addedge [$g addnode] label "NM"

graphHandle delete

nodeHandle delete

edgeHandle delete

Delete all data structures associated with the graph, node or edge from the internal storage of
the interpreter. Deletion of a node also results in the the deletion of all subtending edges on
that node. Deletion of a graph also results in the deletion of all nodes and subgraphs within
that graph (and hence all edges too). The return from these delete commands is a null string.

graphHandle countnodes

graphHandle countedges

Returns the number of nodes, or edges, in the graph.

graphHandle listedges

graphHandle listnodes

graphHandle listnodesrev

graphHandle listsubgraphs

nodeHandle listedges

nodeHandle listinedges

nodeHandle listoutedges

edgeHandle listnodes

Each return a list of handles of graphs, nodes or edges, as appropriate.

graphHandle findnode nodeName

graphHandle findedge tailnodeName headNodeName

nodeHandle findedge nodeName

Each return the handle of the item if found, or an error if none are found. For non-strict graphs
when there are multiple edges between two nodes findedge will return an arbitrary edge from the
set.

graphHandle showname

nodeHandle showname

edgeHandle showname

Each return the name of the item. Edge names are of the form: "a->b" where "a" and "b" are the
names of the nodes and the connector "->" indicates the tail-to-head direction of the edge. In
undirected graphs the connector "--" is used.

graphHandle setnodeattributes attributeName attributeValue ?...?

graphHandle setedgeattributes attributeName attributeValue ?...?

Set one or more default attribute name/values that are to apply to all nodes (edges) unless
overridden by subgraphs or per-node (per-edge) attributes.

graphHandle listnodeattributes

graphHandle listedgeattributes

Return a list of attribute names.

graphHandle querynodeattributes attributeName ?...?

graphHandle queryedgeattributes attributeName ?...?

Return a list of default attribute value, one value for each of the attribute names provided with
the command.

graphHandle querynodeattributes attributeName ?...?

graphHandle queryedgeattributes attributeName ?...?

Return a list of pairs of attrinute name and default attribute value, one pair for each of the
attribute names provided with the command.

graphHandle setattributes attributeName attributeValue ?...?

nodeHandle setattributes attributeName attributeValue ?...?

edgeHandle setattributes attributeName attributeValue ?...?

Set one or more attribute name/value pairs for a specific graph, node, or edge instance.

graphHandle listattributes

nodeHandle listattributes

edgeHandle listattributes

Return a list of attribute names (attribute values are provided by queryattribute

graphHandle queryattributes attributeName ?...?

nodeHandle queryattributes attributeName ?...?

edgeHandle queryattributes attributeName ?...?

Return a list of attribute value, one value for each of the attribute names provided with the
command.

graphHandle queryattributevalues attributeName ?...?

nodeHandle queryattributevalues attributeName ?...?

edgeHandle queryattributevalues attributeName ?...?

Return a list of pairs or attribute name and attribute value, one value for each of the attribute
names provided with the command.

Annotate the graph with layout information. This commands takes an abstract graph add shape and
position information to it according to the layout engine's rules of eye-pleasing graph layout. If
the layout engine is unspecified then it defaults to dot for directed graphs, and neato otherwise.
If the nop engine is specified then layout infomation from the input graph is used. The result of
the layout is stored as additional attributes name/value pairs in the graph, node and edges.
These attributes are intended to be interpreted by subsequent write or render commands.

Write a graph to the open file represented by fileHandle in a specific format. Possible formats
are: "ps" "mif" "hpgl" "plain" "dot" "gif" "ismap" If the layout hasn't been already done, then it
will be done as part of this operation using the same rules for selecting the layout engine as for
the layout command.

graphHandle rendergd gdHandle

Generates a rendering of a graph to a new or existing gifImage structure (see gdTcl(1) ). Returns
the gdHandle of the image. If the layout hasn't been already done, then it will be done as part
of this operation using the same rules for selecting the layout engine as for the layout command.

If no canvas argument is provided then render returns a string of commands which, when evaluated,
will render the graph to a Tk canvas whose canvasHandle is available in variable $c

If a canvas argument is provided then render produces a set of commands for canvas instead of $c.

If the layout hasn't been already done, then it will be done as part of this operation using the
same rules for selecting the layout engine as for the layout command.

#!/usr/local/bin/wish
package require Tcldot
set c [canvas .c]
pack $c
set g [dotnew digraph rankdir LR]
$g setnodeattribute style filled color white
[$g addnode Hello] addedge [$g addnode World!]
$g layout
if {[info exists debug]} {
puts [$g render] ;# see what render produces
}
eval [$g render]

Render generates a series of canvas commands for each graph element, for example a node typically
consist of two items on the canvas, one for the shape and the other for the label. The canvas
items are automatically tagged (See canvas(n) ) by the commands generated by render. The tags
take one of two forms: text items are tagged with 0<handle> and shapes and lines are rendered with
1<handle>.

The tagging can be used to recognize when a user wants to interact with a graph element using the
mouse. See the script in examples/disp of the tcldot distribution for a demonstration of this
facility.

BUGS

       Still batch-oriented.  It would be nice if the layout was maintained incrementally.  (The  intent  is  to
       address this limitation in graphviz_2_0.)

AUTHOR

       John Ellson (ellson@graphviz.org)

ACKNOWLEDGEMENTS

       John  Ousterhout,  of  course,  for  tcl  and tk.  Steven North and Eleftherios Koutsofios for dot.  Karl
       Lehenbauer and Mark Diekhans of NeoSoft for the handles.c code which was derived from tclXhandles.c.  Tom
       Boutell  of  the Quest Center at Cold Spring Harbor Labs for the gif drawing routines.  Spencer Thomas of
       the University of Michigan for gdTcl.c.  Dayatra Shands for coding much of the initial implementation  of
       tcldot.

KEYWORDS

       graph, tcl, tk, dot, neato.

                                                 Tcl Extensions                                     tcldot(3tcl)