tcldot(3tcl)tcldot(3tcl)NAMEtcldot - graph manipulation in tcl
SYNOPSIS
#!/usr/local/bin/tclsh
package require Tcldot
USAGE
Requires the dynamic loading facilities of tcl7.6 or later.
INTRODUCTIONtcldot is a tcl dynamically loaded extension that incorporates the
directed graph facilities of dot(1), and the undirected graph facili‐
ties 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 manip‐
ulation facilities.
COMMANDStcldot 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 com‐
mand 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, list‐
edges, listnodes, listnodesrev, listsubgraphs, render, rendergd,
queryattributes, queryedgeattributes, querynodeattributes,
queryattributevalues, queryedgeattributevalues, querynodeat‐
tributevalues, setattributes, setedgeattributes, setnodeat‐
tributes, showname, write.
Node methods are:
addedge, listattributes, listedges, listinedges, listoutedges,
queryattributes, queryattributevalues, setattributes, showname.
Edge methods are:
delete, listattributes, listnodes, queryattributes, queryat‐
tributevalues, 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 arbitrar‐
ily 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 [dotread $dotsyntaxstring]
graphHandle addnode ?nodeName? ?attributeName attributeValue? ?...?
creates a new node in the graph whose handle is graphHandle and
returns its nodeHandle. The handle of a node is a string like:
"node0" where the integer value is different for each node.
There can be an arbitrary number of attribute name/value pairs
for the node. Certain special node attributes and permitted
values are described in dot(1), but the programmer can arbitrar‐
ily invent and assign values to additional attributes beyond
these. e.g.
set n [$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 han‐
dles and variables are essential to tcldot's ability to manipu‐
late 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 poten‐
tial 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"] [$g findnode "node99"]
There can be an arbitrary number of attribute name/value pairs
for the edge. Certain special edge attributes and permitted
values are described in dot(1), but the programmer can arbitrar‐
ily invent and assign values to additional attributes beyond
these.
graphHandle addsubgraph ?graphName? ?attributeName attributeValue?
?...?
creates a new subgraph in the graph and returns its graphHandle.
If the graphName is omitted then the name of the subgraph
defaults to it's graphHandle. There can be an arbitrary number
of attribute name/value pairs for the subgraph. Certain special
graph attributes and permitted values are described in dot(1),
but the programmer can arbitrarily invent and assign values to
additional attributes beyond these. e.g.
set sg [$g addsubgraph dinglefactor 6]
Clusters, as described in dot(1), are created by giving the sub‐
graph a name that begins with the string: "cluster". Cluster
can be labelled by using the label attibute. e.g.
set cg [$g addsubgraph cluster_A label dongle dinglefactor 6]
nodeHandle addedge headNode ?attributeName attributeValue? ?...?
creates a new edge from the tail node identified by tha nodeHan‐
dle to the headNode which can be specified either by nodeHandle
or by nodeName (with preference to recognizing the argument as a
handle). The graph in which this is drawn is the graph in which
both nodes are members. There can be an arbitrary number of
attribute name/value pairs for the edge. These edge attributes
and permitted values are described in dot(1). e.g.
[$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 con‐
nector "->" 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 com‐
mand.
graphHandle layout ?dot|neato|circo|twopi|fdp|nop?
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.
graphHandle write fileHandle format ?dot|neato|circo|twopi|fdp|nop?
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.
graphHandle render ?canvas ?dot|neato|circo|twopi|fdp|nop??
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 ele‐
ment, for example a node typically consist of two items on the
canvas, one for the shape and the other for the label. The can‐
vas items are automatically tagged (See canvas(n) ) by the com‐
mands generated by render. The tags take one of two forms: text
items are tagged with 0<handle> and shapes and lines are ren‐
dered with 1<handle>.
The tagging can be used to recognize when a user wants to inter‐
act 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 Elefthe‐
rios 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)
