How to use the command `edgepaint` (with examples)
The edgepaint command is a part of Graphviz, a graph visualization library. It is used to colorize the edges of a graph layout to clarify crossing edges. This can be particularly useful when analyzing complex graph structures with many overlapping edges. The edgepaint command accepts various arguments and can be used in different ways to achieve different results.
Use case 1: Colorize edges of a graph layout to clarify crossing edges
edgepaint path/to/layout1.gv path/to/layout2.gv > path/to/output.gv
Motivation: The motivation behind using this example is to clarify crossing edges in a graph layout by colorizing them. By specifying the paths to multiple graph layout files, the command will colorize the edges in all of them and output the result to a new graph layout file.
Explanation: In this example, we provide the paths to one or more graph layout files (path/to/layout1.gv and path/to/layout2.gv) as arguments to the edgepaint command. The command will then colorize the edges in these layout files to clarify any crossing edges. The > symbol is used to redirect the output to a new graph layout file (path/to/output.gv).
Example output: The path/to/output.gv file will contain the colorized graph layout with all the crossing edges clearly highlighted.
Use case 2: Colorize edges using a color scheme
edgepaint -color-scheme=accent7 path/to/layout.gv > path/to/output.gv
Motivation: The motivation behind using this example is to colorize the edges using a predefined color scheme. The accent7 color scheme, in particular, is provided by Graphviz and can help in visually distinguishing between edges based on their color.
Explanation: In this example, we use the -color-scheme argument followed by the desired color scheme (accent7) to specify the color scheme to be used for coloring the edges. The path/to/layout.gv is the path to the graph layout file that we want to colorize. The > symbol is used to redirect the output to a new graph layout file (path/to/output.gv).
Example output: The path/to/output.gv file will contain the colorized graph layout with edges colored according to the accent7 color scheme.
Use case 3: Lay out a graph and colorize its edges, then convert to a PNG image
dot path/to/input.gv | edgepaint | dot -T png > path/to/output.png
Motivation: The motivation behind using this example is to lay out a graph, colorize its edges using the edgepaint command, and then convert the resulting layout to a PNG image for easy visualization.
Explanation: In this example, we first use the dot command to lay out a graph specified in the path/to/input.gv file. The output of the dot command is piped (|) as input to the edgepaint command, which colorizes the edges. The output of the edgepaint command is then piped as input to another dot command, which converts the layout to a PNG image using the -T png argument. The resulting PNG image is then redirected (>) to the path/to/output.png file.
Example output: The path/to/output.png file will contain the PNG image of the graph with colorized edges.
Use case 4: Display help for edgepaint
edgepaint -?
Motivation: The motivation behind using this example is to get help and information about the edgepaint command and its available options.
Explanation: In this example, we use the -? argument to request help for the edgepaint command. Running this command will display the help information, including the available options and their descriptions.
Example output: Running the edgepaint -? command will display the help information for the edgepaint command in the terminal.
