LaTeX options for graphs

This module provides a class to hold, manipulate and employ various options for rendering a graph in LaTeX, in addition to providing the code that actually generates a LaTeX representation of a (combinatorial) graph.

AUTHORS:

• Rob Beezer (2009-05-20): GraphLatex class

• Fidel Barerra Cruz (2009-05-20): tkz-graph commands to render a graph

• Nicolas M. Thiéry (2010-02): dot2tex/graphviz interface

• Rob Beezer (2010-05-29): Extended range of tkz-graph options

LaTeX Versions of Graphs

Many mathematical objects in Sage have LaTeX representations, and graphs are no exception. For a graph g, the command view(g), issued at the Sage command line or in the notebook, will create a graphic version of g. Similarly, latex(g) will return a (long) string that is a representation of the graph in LaTeX. Other ways of employing LaTeX in Sage, such as %latex in a notebook cell, or the Typeset checkbox in the notebook, will handle g appropriately.

Support through the tkz-graph package is by Alain Matthes, the author of tkz-graph, whose work can be found at https://www.ctan.org/pkg/tkz-graph.

The range of possible options for customizing the appearance of a graph are carefully documented at sage.graphs.graph_latex.GraphLatex.set_option(). As a broad overview, the following options are supported:

• Pre-built Styles: the pre-built styles of the tkz-graph package provide nice drawings quickly

• Dimensions: can be specified in natural units, then uniformly scaled after design work

• Vertex Colors: the perimeter and fill color for vertices can be specified, including on a per-vertex basis

• Vertex Shapes: may be circles, shaded spheres, rectangles or diamonds, including on a per-vertex basis

• Vertex Sizes: may be specified as minimums, and will automatically sized to contain vertex labels, including on a per-vertex basis

• Vertex Labels: can use latex formatting, and may have their colors specified, including on a per-vertex basis

• Vertex Label Placement: can be interior to the vertex, or external at a configurable location

• Edge Colors: a solid color with or without a second color down the middle, on a per-edge basis

• Edge Thickness: can be set, including on a per-edge basis

• Edge Labels: can use latex formatting, and may have their colors specified, including on a per-edge basis

• Edge Label Placement: can be to the left, right, above, below, inline, and then sloped or horizontal

• Digraph Edges: are slightly curved, with arrowheads

• Loops: may be specified by their size, and with a direction equaling one of the four compass points

To use LaTeX in Sage you of course need a working TeX installation and it will work best if you have the dvipng and convert utilities. For graphs you need the tkz-graph.sty and tkz-berge.sty style files of the tkz-graph package. TeX, dvipng, and convert should be widely available through package managers or installers. You may need to install the tkz-graph style files in the appropriate locations, a task beyond the scope of this introduction. Primary locations for these programs are:

• TeX: http://ctan.org/

• dvipng: http://sourceforge.net/projects/dvipng/

• convert: http://www.imagemagick.org (the ImageMagick suite)

• tkz-graph: https://www.ctan.org/pkg/tkz-graph

Customizing the output is accomplished in several ways. Suppose g is a graph, then g.set_latex_options() can be used to efficiently set or modify various options. Setting individual options, or querying options, can be accomplished by first using a command like opts = g.latex_options() to obtain a sage.graphs.graph_latex.GraphLatex object which has several methods to set and retrieve options.

Here is a minimal session demonstrating how to use these features. The following setup should work in the notebook or at the command-line.:

sage: H = graphs.HeawoodGraph()
sage: H.set_latex_options(
....:     graphic_size=(5,5),
....:     vertex_size=0.2,
....:     edge_thickness=0.04,
....:     edge_color='green',
....:     vertex_color='green',
....:     vertex_label_color='red'
....: )

At this point, view(H) should call pdflatex to process the string created by latex(H) and then display the resulting graphic.

To use this image in a LaTeX document, you could of course just copy and save the resulting graphic. However, the latex() command will produce the underlying LaTeX code, which can be incorporated into a standalone LaTeX document.:

sage: from sage.graphs.graph_latex import check_tkz_graph
sage: check_tkz_graph()  # random - depends on TeX installation
sage: latex(H)
\begin{tikzpicture}
\definecolor{cv0}{rgb}{0.0,0.502,0.0}
\definecolor{cfv0}{rgb}{1.0,1.0,1.0}
\definecolor{clv0}{rgb}{1.0,0.0,0.0}
\definecolor{cv1}{rgb}{0.0,0.502,0.0}
\definecolor{cfv1}{rgb}{1.0,1.0,1.0}
\definecolor{clv1}{rgb}{1.0,0.0,0.0}
\definecolor{cv2}{rgb}{0.0,0.502,0.0}
\definecolor{cfv2}{rgb}{1.0,1.0,1.0}
\definecolor{clv2}{rgb}{1.0,0.0,0.0}
\definecolor{cv3}{rgb}{0.0,0.502,0.0}
\definecolor{cfv3}{rgb}{1.0,1.0,1.0}
\definecolor{clv3}{rgb}{1.0,0.0,0.0}
\definecolor{cv4}{rgb}{0.0,0.502,0.0}
\definecolor{cfv4}{rgb}{1.0,1.0,1.0}
\definecolor{clv4}{rgb}{1.0,0.0,0.0}
\definecolor{cv5}{rgb}{0.0,0.502,0.0}
\definecolor{cfv5}{rgb}{1.0,1.0,1.0}
\definecolor{clv5}{rgb}{1.0,0.0,0.0}
\definecolor{cv6}{rgb}{0.0,0.502,0.0}
\definecolor{cfv6}{rgb}{1.0,1.0,1.0}
\definecolor{clv6}{rgb}{1.0,0.0,0.0}
\definecolor{cv7}{rgb}{0.0,0.502,0.0}
\definecolor{cfv7}{rgb}{1.0,1.0,1.0}
\definecolor{clv7}{rgb}{1.0,0.0,0.0}
\definecolor{cv8}{rgb}{0.0,0.502,0.0}
\definecolor{cfv8}{rgb}{1.0,1.0,1.0}
\definecolor{clv8}{rgb}{1.0,0.0,0.0}
\definecolor{cv9}{rgb}{0.0,0.502,0.0}
\definecolor{cfv9}{rgb}{1.0,1.0,1.0}
\definecolor{clv9}{rgb}{1.0,0.0,0.0}
\definecolor{cv10}{rgb}{0.0,0.502,0.0}
\definecolor{cfv10}{rgb}{1.0,1.0,1.0}
\definecolor{clv10}{rgb}{1.0,0.0,0.0}
\definecolor{cv11}{rgb}{0.0,0.502,0.0}
\definecolor{cfv11}{rgb}{1.0,1.0,1.0}
\definecolor{clv11}{rgb}{1.0,0.0,0.0}
\definecolor{cv12}{rgb}{0.0,0.502,0.0}
\definecolor{cfv12}{rgb}{1.0,1.0,1.0}
\definecolor{clv12}{rgb}{1.0,0.0,0.0}
\definecolor{cv13}{rgb}{0.0,0.502,0.0}
\definecolor{cfv13}{rgb}{1.0,1.0,1.0}
\definecolor{clv13}{rgb}{1.0,0.0,0.0}
\definecolor{cv0v1}{rgb}{0.0,0.502,0.0}
\definecolor{cv0v5}{rgb}{0.0,0.502,0.0}
\definecolor{cv0v13}{rgb}{0.0,0.502,0.0}
\definecolor{cv1v2}{rgb}{0.0,0.502,0.0}
\definecolor{cv1v10}{rgb}{0.0,0.502,0.0}
\definecolor{cv2v3}{rgb}{0.0,0.502,0.0}
\definecolor{cv2v7}{rgb}{0.0,0.502,0.0}
\definecolor{cv3v4}{rgb}{0.0,0.502,0.0}
\definecolor{cv3v12}{rgb}{0.0,0.502,0.0}
\definecolor{cv4v5}{rgb}{0.0,0.502,0.0}
\definecolor{cv4v9}{rgb}{0.0,0.502,0.0}
\definecolor{cv5v6}{rgb}{0.0,0.502,0.0}
\definecolor{cv6v7}{rgb}{0.0,0.502,0.0}
\definecolor{cv6v11}{rgb}{0.0,0.502,0.0}
\definecolor{cv7v8}{rgb}{0.0,0.502,0.0}
\definecolor{cv8v9}{rgb}{0.0,0.502,0.0}
\definecolor{cv8v13}{rgb}{0.0,0.502,0.0}
\definecolor{cv9v10}{rgb}{0.0,0.502,0.0}
\definecolor{cv10v11}{rgb}{0.0,0.502,0.0}
\definecolor{cv11v12}{rgb}{0.0,0.502,0.0}
\definecolor{cv12v13}{rgb}{0.0,0.502,0.0}
%
\Vertex[style={minimum size=0.2cm,draw=cv0,fill=cfv0,text=clv0,shape=circle},LabelOut=false,L=\hbox{$0$},x=2.5cm,y=5.0cm]{v0}
\Vertex[style={minimum size=0.2cm,draw=cv1,fill=cfv1,text=clv1,shape=circle},LabelOut=false,L=\hbox{$1$},x=1.3874cm,y=4.7524cm]{v1}
\Vertex[style={minimum size=0.2cm,draw=cv2,fill=cfv2,text=clv2,shape=circle},LabelOut=false,L=\hbox{$2$},x=0.4952cm,y=4.0587cm]{v2}
\Vertex[style={minimum size=0.2cm,draw=cv3,fill=cfv3,text=clv3,shape=circle},LabelOut=false,L=\hbox{$3$},x=0.0cm,y=3.0563cm]{v3}
\Vertex[style={minimum size=0.2cm,draw=cv4,fill=cfv4,text=clv4,shape=circle},LabelOut=false,L=\hbox{$4$},x=0.0cm,y=1.9437cm]{v4}
\Vertex[style={minimum size=0.2cm,draw=cv5,fill=cfv5,text=clv5,shape=circle},LabelOut=false,L=\hbox{$5$},x=0.4952cm,y=0.9413cm]{v5}
\Vertex[style={minimum size=0.2cm,draw=cv6,fill=cfv6,text=clv6,shape=circle},LabelOut=false,L=\hbox{$6$},x=1.3874cm,y=0.2476cm]{v6}
\Vertex[style={minimum size=0.2cm,draw=cv7,fill=cfv7,text=clv7,shape=circle},LabelOut=false,L=\hbox{$7$},x=2.5cm,y=0.0cm]{v7}
\Vertex[style={minimum size=0.2cm,draw=cv8,fill=cfv8,text=clv8,shape=circle},LabelOut=false,L=\hbox{$8$},x=3.6126cm,y=0.2476cm]{v8}
\Vertex[style={minimum size=0.2cm,draw=cv9,fill=cfv9,text=clv9,shape=circle},LabelOut=false,L=\hbox{$9$},x=4.5048cm,y=0.9413cm]{v9}
\Vertex[style={minimum size=0.2cm,draw=cv10,fill=cfv10,text=clv10,shape=circle},LabelOut=false,L=\hbox{$10$},x=5.0cm,y=1.9437cm]{v10}
\Vertex[style={minimum size=0.2cm,draw=cv11,fill=cfv11,text=clv11,shape=circle},LabelOut=false,L=\hbox{$11$},x=5.0cm,y=3.0563cm]{v11}
\Vertex[style={minimum size=0.2cm,draw=cv12,fill=cfv12,text=clv12,shape=circle},LabelOut=false,L=\hbox{$12$},x=4.5048cm,y=4.0587cm]{v12}
\Vertex[style={minimum size=0.2cm,draw=cv13,fill=cfv13,text=clv13,shape=circle},LabelOut=false,L=\hbox{$13$},x=3.6126cm,y=4.7524cm]{v13}
%
\Edge[lw=0.04cm,style={color=cv0v1,},](v0)(v1)
\Edge[lw=0.04cm,style={color=cv0v5,},](v0)(v5)
\Edge[lw=0.04cm,style={color=cv0v13,},](v0)(v13)
\Edge[lw=0.04cm,style={color=cv1v2,},](v1)(v2)
\Edge[lw=0.04cm,style={color=cv1v10,},](v1)(v10)
\Edge[lw=0.04cm,style={color=cv2v3,},](v2)(v3)
\Edge[lw=0.04cm,style={color=cv2v7,},](v2)(v7)
\Edge[lw=0.04cm,style={color=cv3v4,},](v3)(v4)
\Edge[lw=0.04cm,style={color=cv3v12,},](v3)(v12)
\Edge[lw=0.04cm,style={color=cv4v5,},](v4)(v5)
\Edge[lw=0.04cm,style={color=cv4v9,},](v4)(v9)
\Edge[lw=0.04cm,style={color=cv5v6,},](v5)(v6)
\Edge[lw=0.04cm,style={color=cv6v7,},](v6)(v7)
\Edge[lw=0.04cm,style={color=cv6v11,},](v6)(v11)
\Edge[lw=0.04cm,style={color=cv7v8,},](v7)(v8)
\Edge[lw=0.04cm,style={color=cv8v9,},](v8)(v9)
\Edge[lw=0.04cm,style={color=cv8v13,},](v8)(v13)
\Edge[lw=0.04cm,style={color=cv9v10,},](v9)(v10)
\Edge[lw=0.04cm,style={color=cv10v11,},](v10)(v11)
\Edge[lw=0.04cm,style={color=cv11v12,},](v11)(v12)
\Edge[lw=0.04cm,style={color=cv12v13,},](v12)(v13)
%
\end{tikzpicture}

EXAMPLES:

This example illustrates switching between the built-in styles when using the tkz_graph format.:

sage: g = graphs.PetersenGraph()
sage: g.set_latex_options(tkz_style='Classic')
sage: from sage.graphs.graph_latex import check_tkz_graph
sage: check_tkz_graph()  # random - depends on TeX installation
sage: latex(g)
\begin{tikzpicture}
\GraphInit[vstyle=Classic]
...
\end{tikzpicture}
sage: opts = g.latex_options()
sage: opts
LaTeX options for Petersen graph: {'tkz_style': 'Classic'}
sage: g.set_latex_options(tkz_style = 'Art')
sage: opts.get_option('tkz_style')
'Art'
sage: opts
LaTeX options for Petersen graph: {'tkz_style': 'Art'}
sage: latex(g)
\begin{tikzpicture}
\GraphInit[vstyle=Art]
...
\end{tikzpicture}

This example illustrates using the optional dot2tex module:

sage: g = graphs.PetersenGraph()
sage: g.set_latex_options(format='dot2tex', prog='neato')
sage: from sage.graphs.graph_latex import check_tkz_graph
sage: check_tkz_graph()  # random - depends on TeX installation
sage: latex(g)  # optional - dot2tex graphviz
\begin{tikzpicture}[>=latex,line join=bevel,]
...
\end{tikzpicture}

Among other things, this supports the flexible edge_options option (see sage.graphs.generic_graph.GenericGraph.graphviz_string()); here we color in red all edges touching the vertex 0:

sage: g = graphs.PetersenGraph()
sage: g.set_latex_options(format="dot2tex", edge_options=lambda u_v_label: {"color": "red"} if u_v_label[0] == 0 else {})
sage: latex(g)  # optional - dot2tex graphviz
\begin{tikzpicture}[>=latex,line join=bevel,]
...
\end{tikzpicture}

GraphLatex class and functions

class sage.graphs.graph_latex.GraphLatex(graph, **options)

Bases: SageObject

A class to hold, manipulate and employ options for converting a graph to LaTeX.

This class serves two purposes. First it holds the values of various options designed to work with the tkz-graph LaTeX package for rendering graphs. As such, a graph that uses this class will hold a reference to it. Second, this class contains the code to convert a graph into the corresponding LaTeX constructs, returning a string.

EXAMPLES:

sage: from sage.graphs.graph_latex import GraphLatex
sage: opts = GraphLatex(graphs.PetersenGraph())
sage: opts
LaTeX options for Petersen graph: {}
sage: g = graphs.PetersenGraph()
sage: opts = g.latex_options()
sage: g == loads(dumps(g))
True

dot2tex_picture()

Call dot2tex to construct a string of LaTeX commands representing a graph as a tikzpicture.

EXAMPLES:

sage: g = digraphs.ButterflyGraph(1)
sage: from sage.graphs.graph_latex import check_tkz_graph
sage: check_tkz_graph()  # random - depends on TeX installation
sage: print(g.latex_options().dot2tex_picture())  # optional - dot2tex graphviz
\begin{tikzpicture}[>=latex,line join=bevel,]
%%
  \node (node_...) at (...bp,...bp) [draw,draw=none] {$\left(...\right)$};
  \node (node_...) at (...bp,...bp) [draw,draw=none] {$\left(...\right)$};
  \node (node_...) at (...bp,...bp) [draw,draw=none] {$\left(...\right)$};
  \node (node_...) at (...bp,...bp) [draw,draw=none] {$\left(...\right)$};
  \draw [black,->] (node_...) ..controls (...bp,...bp) and (...bp,...bp)  .. (node_...);
  \draw [black,->] (node_...) ..controls (...bp,...bp) and (...bp,...bp)  .. (node_...);
  \draw [black,->] (node_...) ..controls (...bp,...bp) and (...bp,...bp)  .. (node_...);
  \draw [black,->] (node_...) ..controls (...bp,...bp) and (...bp,...bp)  .. (node_...);
%
\end{tikzpicture}

We make sure github issue #13624 is fixed:

sage: G = DiGraph()
sage: G.add_edge(3333, 88, 'my_label')
sage: G.set_latex_options(edge_labels=True)
sage: print(G.latex_options().dot2tex_picture())  # optional - dot2tex graphviz
\begin{tikzpicture}[>=latex,line join=bevel,]
%%
\node (node_...) at (...bp,...bp) [draw,draw=none] {$...$};
  \node (node_...) at (...bp,...bp) [draw,draw=none] {$...$};
  \draw [black,->] (node_...) ..controls (...bp,...bp) and (...bp,...bp)  .. (node_...);
  \definecolor{strokecol}{rgb}{0.0,0.0,0.0};
  \pgfsetstrokecolor{strokecol}
  \draw (...bp,...bp) node {$\text{\texttt{my{\char`\_}label}}$};
%
\end{tikzpicture}

Check that github issue #25120 is fixed:

sage: G = Graph([(0,1)])
sage: G.set_latex_options(edge_colors = {(0,1): 'red'})
sage: print(G.latex_options().dot2tex_picture())  # optional - dot2tex graphviz
\begin{tikzpicture}[>=latex,line join=bevel,]
...
\draw [red,] (node_0) ... (node_1);
...
\end{tikzpicture}

Note

There is a lot of overlap between what tkz_picture and dot2tex do. It would be best to merge them! dot2tex probably can work without graphviz if layout information is provided.

get_option(option_name)

Return the current value of the named option.

INPUT:

• option_name – the name of an option

OUTPUT:

If the name is not present in __graphlatex_options it is an error to ask for it. If an option has not been set then the default value is returned. Otherwise, the value of the option is returned.

EXAMPLES:

sage: g = graphs.PetersenGraph()
sage: opts = g.latex_options()
sage: opts.set_option('tkz_style', 'Art')
sage: opts.get_option('tkz_style')
'Art'
sage: opts.set_option('tkz_style')
sage: opts.get_option('tkz_style') == "Custom"
True
sage: opts.get_option('bad_name')
Traceback (most recent call last):
...
ValueError: bad_name is not a Latex option for a graph.

latex()

Return a string in LaTeX representing a graph.

This is the command that is invoked by sage.graphs.generic_graph.GenericGraph._latex_ for a graph, so it returns a string of LaTeX commands that can be incorporated into a LaTeX document unmodified. The exact contents of this string are influenced by the options set via the methods sage.graphs.generic_graph.GenericGraph.set_latex_options(), set_option(), and set_options().

By setting the format option different packages can be used to create the latex version of a graph. Supported packages are tkz-graph and dot2tex.

EXAMPLES:

sage: from sage.graphs.graph_latex import check_tkz_graph
sage: check_tkz_graph()  # random - depends on TeX installation
sage: g = graphs.CompleteGraph(2)
sage: opts = g.latex_options()
sage: print(opts.latex())
\begin{tikzpicture}
\definecolor{cv0}{rgb}{0.0,0.0,0.0}
\definecolor{cfv0}{rgb}{1.0,1.0,1.0}
\definecolor{clv0}{rgb}{0.0,0.0,0.0}
\definecolor{cv1}{rgb}{0.0,0.0,0.0}
\definecolor{cfv1}{rgb}{1.0,1.0,1.0}
\definecolor{clv1}{rgb}{0.0,0.0,0.0}
\definecolor{cv0v1}{rgb}{0.0,0.0,0.0}
%
\Vertex[style={minimum size=1.0cm,draw=cv0,fill=cfv0,text=clv0,shape=circle},LabelOut=false,L=\hbox{$0$},x=2.5cm,y=5.0cm]{v0}
\Vertex[style={minimum size=1.0cm,draw=cv1,fill=cfv1,text=clv1,shape=circle},LabelOut=false,L=\hbox{$1$},x=2.5cm,y=0.0cm]{v1}
%
\Edge[lw=0.1cm,style={color=cv0v1,},](v0)(v1)
%
\end{tikzpicture}

We check that github issue #22070 is fixed:

sage: edges = [(i,(i+1)%3,a) for i,a in enumerate('abc')]
sage: G_with_labels = DiGraph(edges)
sage: C = [[0,1], [2]]
sage: kwds = dict(subgraph_clusters=C,color_by_label=True,prog='dot',format='dot2tex')
sage: opts = G_with_labels.latex_options()
sage: opts.set_options(edge_labels=True, **kwds)  # optional - dot2tex graphviz
sage: latex(G_with_labels)                        # optional - dot2tex graphviz
\begin{tikzpicture}[>=latex,line join=bevel,]
%%
\begin{scope}
  \pgfsetstrokecolor{black}
  \definecolor{strokecol}{rgb}{...};
  \pgfsetstrokecolor{strokecol}
  \definecolor{fillcol}{rgb}{...};
  \pgfsetfillcolor{fillcol}
  \filldraw ... cycle;
\end{scope}
\begin{scope}
  \pgfsetstrokecolor{black}
  \definecolor{strokecol}{rgb}{...};
  \pgfsetstrokecolor{strokecol}
  \definecolor{fillcol}{rgb}{...};
  \pgfsetfillcolor{fillcol}
  \filldraw ... cycle;
\end{scope}
...
\end{tikzpicture}

set_option(option_name, option_value=None)

Set, modify, clear a LaTeX option for controlling the rendering of a graph.

The possible options are documented here, because ultimately it is this routine that sets the values. However, the sage.graphs.generic_graph.GenericGraph.set_latex_options() method is the easiest way to set options, and allows several to be set at once.

INPUT:

• option_name – a string for a latex option contained in the list sage.graphs.graph_latex.GraphLatex.__graphlatex_options. A ValueError is raised if the option is not allowed.

• option_value – a value for the option. If omitted, or set to None, the option will use the default value.

The output can be either handled internally by Sage, or delegated to the external software dot2tex and graphviz. This is controlled by the option format:

• format – string (default: 'tkz_graph'); either 'dot2tex' or 'tkz_graph'.

If format is 'dot2tex', then all the LaTeX generation will be delegated to dot2tex (which must be installed).

For tkz_graph, the possible option names, and associated values are given below. This first group allows you to set a style for a graph and specify some sizes related to the eventual image. (For more information consult the documentation for the tkz-graph package.)

• tkz_style – string (default: 'Custom'); the name of a pre-defined tkz-graph style such as 'Shade', 'Art', 'Normal', 'Dijkstra', 'Welsh', 'Classic', and 'Simple', or the string 'Custom'. Using one of these styles alone will often give a reasonably good drawing with minimal effort. For a custom appearance set this to 'Custom' and use the options described below to override the default values.

• units – string (default: 'cm') – a natural unit of measurement used for all dimensions. Possible values are: 'in', 'mm', 'cm', 'pt', 'em', 'ex'.

• scale – float (default: 1.0); a dimensionless number that multiplies every linear dimension. So you can design at sizes you are accustomed to, then shrink or expand to meet other needs. Though fonts do not scale.

• graphic_size – tuple (default: (5, 5)); overall dimensions (width, length) of the bounding box around the entire graphic image.

• margins – 4-tuple (default: (0, 0, 0, 0)); portion of graphic given over to a plain border as a tuple of four numbers: (left, right, top, bottom). These are subtracted from the graphic_size to create the area left for the vertices of the graph itself. Note that the processing done by Sage will trim the graphic down to the minimum possible size, removing any border. So this is only useful if you use the latex string in a latex document.

If not using a pre-built style the following options are used, so the following defaults will apply. It is not possible to begin with a pre-built style and modify it (other than editing the latex string by hand after the fact).

• vertex_color – (default: 'black'); a single color to use as the default for outline of vertices. For the sphere shape this color is used for the entire vertex, which is drawn with a 3D shading. Colors must be specified as a string recognized by the matplotlib library: a standard color name like 'red', or a hex string like '#2D87A7', or a single character from the choices 'rgbcmykw'. Additionally, a number between 0 and 1 will create a grayscale value. These color specifications are consistent throughout the options for a tikzpicture.

• vertex_colors – a dictionary whose keys are vertices of the graph and whose values are colors. These will be used to color the outline of vertices. See the explanation above for the vertex_color option to see possible values. These values need only be specified for a proper subset of the vertices. Specified values will supersede a default value.

• vertex_fill_color – (default: 'white'); a single color to use as the default for the fill color of vertices. See the explanation above for the vertex_color option to see possible values. This color is ignored for the sphere vertex shape.

• vertex_fill_colors – a dictionary whose keys are vertices of the graph and whose values are colors. These will be used to fill the interior of vertices. See the explanation above for the vertex_color option to see possible values. These values need only be specified for a proper subset of the vertices. Specified values will supersede a default value.

• vertex_shape – string (default: 'circle'); specifies the shape of the vertices. Allowable values are 'circle', 'sphere', 'rectangle', 'diamond'. The sphere shape has a 3D look to its coloring and is uses only one color, that specified by vertex_color and vertex_colors, which are normally used for the outline of the vertex.

• vertex_shapes – a dictionary whose keys are vertices of the graph and whose values are shapes. See vertex_shape for the allowable possibilities.

• vertex_size – float (default: 1.0); the minimum size of a vertex as a number. Vertices will expand to contain their labels if the labels are placed inside the vertices. If you set this value to zero the vertex will be as small as possible (up to tkz-graph’s “inner sep” parameter), while still containing labels. However, if labels are not of a uniform size, then the vertices will not be either.

• vertex_sizes – a dictionary of sizes for some of the vertices.

• vertex_labels – boolean (default: True); determine whether or not to display the vertex labels. If False subsequent options about vertex labels are ignored.

• vertex_labels_math – boolean (default: True); when True, if a label is a string that begins and ends with dollar signs, then the string will be rendered as a latex string. Otherwise, the label will be automatically subjected to the latex() method and rendered accordingly. If False the label is rendered as its textual representation according to the _repr method. Support for arbitrarily-complicated mathematics is not especially robust.

• vertex_label_color – (default: 'black'); a single color to use as the default for labels of vertices. See the explanation above for the vertex_color option to see possible values.

• vertex_label_colors – a dictionary whose keys are vertices of the graph and whose values are colors. These will be used for the text of the labels of vertices. See the explanation above for the vertex_color option to see possible values. These values need only be specified for a proper subset of the vertices. Specified values will supersede a default value.

• vertex_label_placement – (default: 'center'); if 'center' the label is centered in the interior of the vertex and the vertex will expand to contain the label. Giving instead a pair of numbers will place the label exterior to the vertex at a certain distance from the edge, and at an angle to the positive x-axis, similar in spirit to polar coordinates.

• vertex_label_placements – a dictionary of placements indexed by the vertices. See the explanation for vertex_label_placement for the possible values.

• edge_color – (default: 'black'); a single color to use as the default for an edge. See the explanation above for the vertex_color option to see possible values.

• edge_colors – a dictionary whose keys are edges of the graph and whose values are colors. These will be used to color the edges. See the explanation above for the vertex_color option to see possible values. These values need only be specified for a proper subset of the vertices. Specified values will supersede a default value.

• edge_fills – boolean (default: False); whether an edge has a second color running down the middle. This can be a useful effect for highlighting edge crossings.

• edge_fill_color – (default: 'black'); a single color to use as the default for the fill color of an edge. The boolean switch edge_fills must be set to True for this to have an effect. See the explanation above for the vertex_color option to see possible values.

• edge_fill_colors – a dictionary whose keys are edges of the graph and whose values are colors. See the explanation above for the vertex_color option to see possible values. These values need only be specified for a proper subset of the vertices. Specified values will supersede a default value.

• edge_thickness – float (default: 0.1); specifies the width of the edges. Note that tkz-graph does not interpret this number for loops.

• edge_thicknesses – a dictionary of thicknesses for some of the edges of a graph. These values need only be specified for a proper subset of the vertices. Specified values will supersede a default value.

• edge_labels – boolean (default: False); determine if edge labels are shown. If False subsequent options about edge labels are ignored.

• edge_labels_math – boolean (default: True); control how edge labels are rendered. Read the explanation for the vertex_labels_math option, which behaves identically. Support for arbitrarily-complicated mathematics is not especially robust.

• edge_label_color – (default: 'black'); a single color to use as the default for labels of edges. See the explanation above for the vertex_color option to see possible values.

• edge_label_colors – a dictionary whose keys are edges of the graph and whose values are colors. These will be used for the text of the labels of edges. See the explanation above for the vertex_color option to see possible values. These values need only be specified for a proper subset of the vertices. Specified values will supersede a default value. Note that labels must be used for this to have any effect, and no care is taken to ensure that label and fill colors work well together.

• edge_label_sloped – boolean (default: True); specifies how edge labels are place. False results in a horizontal label, while True means the label is rotated to follow the direction of the edge it labels.

• edge_label_slopes – a dictionary of booleans, indexed by some subset of the edges. See the edge_label_sloped option for a description of sloped edge labels.

• edge_label_placement – (default: 0.50); either a number between 0.0 and 1.0, or one of: 'above', 'below', 'left', 'right'. These adjust the location of an edge label along an edge. A number specifies how far along the edge the label is located. 'left' and 'right' are conveniences. 'above' and 'below' move the label off the edge itself while leaving it near the midpoint of the edge. The default value of 0.50 places the label on the midpoint of the edge.

• edge_label_placements – a dictionary of edge placements, indexed by the edges. See the edge_label_placement option for a description of the allowable values.

• loop_placement – (default: (3.0, 'NO')); determine how loops are rendered. the first element of the pair is a distance, which determines how big the loop is and the second element is a string specifying a compass point (North, South, East, West) as one of 'NO', 'SO', 'EA', 'WE'.

• loop_placements – a dictionary of loop placements. See the loop_placements option for the allowable values. While loops are technically edges, this dictionary is indexed by vertices.

For the 'dot2tex' format, the possible option names and associated values are given below:

• prog – string; the program used for the layout. It must be a string corresponding to one of the software of the graphviz suite: 'dot', 'neato', 'twopi', 'circo' or 'fdp'.

• edge_labels – boolean (default: False); whether to display the labels on edges.

• edge_colors – a color; can be used to set a global color to the edge of the graph.

• color_by_label – boolean (default: False); colors the edges according to their labels

• subgraph_clusters – (default: []) a list of lists of vertices, if supported by the layout engine, nodes belonging to the same cluster subgraph are drawn together, with the entire drawing of the cluster contained within a bounding rectangle.

OUTPUT:

There are none. Success happens silently.

EXAMPLES:

Set, then modify, then clear the tkz_style option, and finally show an error for an unrecognized option name:

sage: g = graphs.PetersenGraph()
sage: opts = g.latex_options()
sage: opts
LaTeX options for Petersen graph: {}
sage: opts.set_option('tkz_style', 'Art')
sage: opts
LaTeX options for Petersen graph: {'tkz_style': 'Art'}
sage: opts.set_option('tkz_style', 'Simple')
sage: opts
LaTeX options for Petersen graph: {'tkz_style': 'Simple'}
sage: opts.set_option('tkz_style')
sage: opts
LaTeX options for Petersen graph: {}
sage: opts.set_option('bad_name', 'nonsense')
Traceback (most recent call last):
...
ValueError: bad_name is not a LaTeX option for a graph.

See sage.graphs.generic_graph.GenericGraph.layout_graphviz() for installation instructions for graphviz and dot2tex. Furthermore, pgf >= 2.00 should be available inside LaTeX’s tree for LaTeX compilation (e.g. when using view). In case your LaTeX distribution does not provide it, here are short instructions:

• download pgf from http://sourceforge.net/projects/pgf/

• unpack it in /usr/share/texmf/tex/generic (depends on your system)

• clean out remaining pgf files from older version

• run texhash

set_options(**kwds)

Set several LaTeX options for a graph all at once.

INPUT:

• kwds – any number of option/value pairs to set many graph latex options at once (a variable number, in any order). Existing values are overwritten, new values are added. Existing values can be cleared by setting the value to None. Errors are raised in the set_option() method.

EXAMPLES:

sage: g = graphs.PetersenGraph()
sage: opts = g.latex_options()
sage: opts.set_options(tkz_style='Welsh')
sage: opts.get_option('tkz_style')
'Welsh'

tkz_picture()

Return a string of LaTeX commands representing a graph as a tikzpicture.

This routine interprets the graph’s properties and the options in _options to render the graph with commands from the tkz-graph LaTeX package.

This requires that the LaTeX optional packages tkz-graph and tkz-berge be installed. You may also need a current version of the pgf package. If the tkz-graph and tkz-berge packages are present in the system’s TeX installation, the appropriate \\usepackage{} commands will be added to the LaTeX preamble as part of the initialization of the graph. If these two packages are not present, then this command will return a warning on its first use, but will return a string that could be used elsewhere, such as a LaTeX document.

For more information about tkz-graph you can visit https://www.ctan.org/pkg/tkz-graph.

EXAMPLES:

With a pre-built tkz-graph style specified, the latex representation will be relatively simple.

sage: from sage.graphs.graph_latex import check_tkz_graph
sage: check_tkz_graph()  # random - depends on TeX installation
sage: g = graphs.CompleteGraph(3)
sage: opts = g.latex_options()
sage: g.set_latex_options(tkz_style='Art')
sage: print(opts.tkz_picture())
\begin{tikzpicture}
\GraphInit[vstyle=Art]
%
\Vertex[L=\hbox{$0$},x=2.5cm,y=5.0cm]{v0}
\Vertex[L=\hbox{$1$},x=0.0cm,y=0.0cm]{v1}
\Vertex[L=\hbox{$2$},x=5.0cm,y=0.0cm]{v2}
%
\Edge[](v0)(v1)
\Edge[](v0)(v2)
\Edge[](v1)(v2)
%
\end{tikzpicture}

Setting the style to “Custom” results in various configurable aspects set to the defaults, so the string is more involved.

sage: from sage.graphs.graph_latex import check_tkz_graph
sage: check_tkz_graph()  # random - depends on TeX installation
sage: g = graphs.CompleteGraph(3)
sage: opts = g.latex_options()
sage: g.set_latex_options(tkz_style='Custom')
sage: print(opts.tkz_picture())
\begin{tikzpicture}
\definecolor{cv0}{rgb}{0.0,0.0,0.0}
\definecolor{cfv0}{rgb}{1.0,1.0,1.0}
\definecolor{clv0}{rgb}{0.0,0.0,0.0}
\definecolor{cv1}{rgb}{0.0,0.0,0.0}
\definecolor{cfv1}{rgb}{1.0,1.0,1.0}
\definecolor{clv1}{rgb}{0.0,0.0,0.0}
\definecolor{cv2}{rgb}{0.0,0.0,0.0}
\definecolor{cfv2}{rgb}{1.0,1.0,1.0}
\definecolor{clv2}{rgb}{0.0,0.0,0.0}
\definecolor{cv0v1}{rgb}{0.0,0.0,0.0}
\definecolor{cv0v2}{rgb}{0.0,0.0,0.0}
\definecolor{cv1v2}{rgb}{0.0,0.0,0.0}
%
\Vertex[style={minimum size=1.0cm,draw=cv0,fill=cfv0,text=clv0,shape=circle},LabelOut=false,L=\hbox{$0$},x=2.5cm,y=5.0cm]{v0}
\Vertex[style={minimum size=1.0cm,draw=cv1,fill=cfv1,text=clv1,shape=circle},LabelOut=false,L=\hbox{$1$},x=0.0cm,y=0.0cm]{v1}
\Vertex[style={minimum size=1.0cm,draw=cv2,fill=cfv2,text=clv2,shape=circle},LabelOut=false,L=\hbox{$2$},x=5.0cm,y=0.0cm]{v2}
%
\Edge[lw=0.1cm,style={color=cv0v1,},](v0)(v1)
\Edge[lw=0.1cm,style={color=cv0v2,},](v0)(v2)
\Edge[lw=0.1cm,style={color=cv1v2,},](v1)(v2)
%
\end{tikzpicture}

See the introduction to the graph_latex module for more information on the use of this routine.

sage.graphs.graph_latex.check_tkz_graph()

Check if the proper LaTeX packages for the tikzpicture environment are installed in the user’s environment, and issue a warning otherwise.

The warning is only issued on the first call to this function. So any doctest that illustrates the use of the tkz-graph packages should call this once as having random output to exhaust the warnings before testing output.

See also sage.misc.latex.Latex.check_file()

sage.graphs.graph_latex.have_tkz_graph()

Return True if the proper LaTeX packages for the tikzpicture environment are installed in the user’s environment, namely tikz, tkz-graph and tkz-berge.

The result is cached.

See also sage.misc.latex.Latex.has_file()

sage.graphs.graph_latex.setup_latex_preamble()

Add appropriate \usepackage{...}, and other instructions to the latex preamble for the packages that are needed for processing graphs(tikz, tkz-graph, tkz-berge), if available in the LaTeX installation.

See also sage.misc.latex.Latex.add_package_to_preamble_if_available().

EXAMPLES:

sage: sage.graphs.graph_latex.setup_latex_preamble()