By default the DrawGraph command draws the edges and vertices of the graph with the same set of style options. HighlightVertex allows you to specify vertices to be given a different highlighted style specified in the graph stylesheet.

Given only a graph G and a vertex or vertices V, HighlightVertex marks the specified vertices to be rendered with the default highlighted style.

If you simply want a vertex to have a different style without being grouped with other highlighted graph components, use the command StyleVertex instead.

If you want to highlight a vertex but give it a different color, the simplest way it to just specify C, the color for the vertex. The colors C can be given in any form understood by Maple. See ColorTools/Formats for details. When the color of the vertex is set, the color of the vertex label is set automatically to an appropriately contrasting grayscale.

If V is a list or Array of vertices, then a list of colors or stylesheets is used to associate a different color or style to each member.

By default, this command modifies G and returns nothing. If you supply the option inplace = false, then instead the changes are applied to a copy of G, and that copy is returned.

More precise overriding of the default highlighted style can be set using stylesheet options. The stylesheet options are understood as modifiers to the default highlighted style. So, for example, if a color is not specified, the default highlighted color is used. If the stylesheet option and a color C are both given, the color C is ignored.  See StyleVertex for a complete list of vertex style options.

$\mathrm{with}\left(\mathrm{GraphTheory}\right)\:$

$\mathrm{K5}≔\mathrm{CompleteGraph}\left(5\right)$

$\mathrm{K5}≔\mathrm{Graph\; 1:\; an\; undirected\; graph\; with\; 5\; vertices\; and\; 10\; edges}$

$\mathrm{HighlightVertex}\left(\mathrm{K5}\,1\right)$

$\mathrm{DrawGraph}\left(\mathrm{K5}\right)$

$\mathrm{HighlightVertex}\left(\mathrm{K5}\,\left\{1\,3\right\}\,''DodgerBlue''\right)$

$\mathrm{DrawGraph}\left(\mathrm{K5}\right)$

$\mathrm{HighlightVertex}\left(\mathrm{K5}\,\left\{1\,3\right\}\,\mathrm{stylesheet}=\left[\mathrm{font}=\left[''Courier''\,''bold''\,14\right]\,\mathrm{thickness}=3\right]\right)$

$\mathrm{DrawGraph}\left(\mathrm{K5}\right)$

$G≔\mathrm{Graph}\left(\left\{\left\{1\,2\right\}\,\left\{1\,3\right\}\,\left\{2\,3\right\}\,\left\{3\,4\right\}\,\left\{4\,5\right\}\,\left\{4\,6\right\}\,\left\{5\,6\right\}\right\}\right)$

$G≔\mathrm{Graph\; 2:\; an\; undirected\; graph\; with\; 6\; vertices\; and\; 7\; edges}$

$A≔\mathrm{ArticulationPoints}\left(G\right)$

$A≔\left[3\,4\right]$

$H≔\mathrm{HighlightVertex}\left(G\,A\,\mathrm{stylesheet}=\left[\mathrm{color}=''Magenta''\,\mathrm{border}=\mathrm{false}\,\mathrm{fontstyle}=''bold''\right]\,\mathrm{inplace}=\mathrm{false}\right)$

$H≔\mathrm{Graph\; 3:\; an\; undirected\; graph\; with\; 6\; vertices\; and\; 7\; edges}$

$\mathrm{DrawGraph}\left(H\right)$

$\mathrm{DrawGraph}\left(G\right)$

$\mathrm{HighlightVertex}\left(G\,\left[1\,5\right]\,\left[''Fill\; Spring\; Blue''\,''Fill\; Spring\; Yellow''\right]\right)$

$\mathrm{DrawGraph}\left(G\right)$

$\mathrm{HighlightVertex}\left(G\,\left[2\,3\right]\,\mathrm{stylesheet}=\left[\left[\mathrm{fontstyle}=''italic''\right]\,\left[\mathrm{fontstyle}=''bold''\right]\right]\right)$

$\mathrm{DrawGraph}\left(G\right)$

The GraphTheory[HighlightVertex] command was updated in Maple 2019.

The stylesheet option was updated in Maple 2019.