proposal: `cmd/modgraphviz`: Colorize edges for more clear view on large graphs

[abdoeid-eg]

Proposal Details

Problem

Description

When using modgraphiz on large codebases, it generates edges colored black which makes it very hard to differentiate between edges when they blend in one big edge like the following.

Proposed solution

We can add a color property to the edge struct; we then populate this property with the same color for all nodes that depend on the current node.

Example

Dot Code

digraph gomodgraph {
    node [ shape=rectangle fontsize=12 ]
    A -> B [color="red"]
    A -> C [color="red"]
    A -> D [color="red"]
    B -> E [color="blue"]
    B -> F [color="blue"]
}

Output

Is this an acceptable solution to start working on and open a PR with?

[abdoeid-eg]

I use this python script to do so till this is implemented

import random

def random_color():
    # Generate a random hex color
    return '#{:06x}'.format(random.randint(0, 0xFFFFFF))

def process_dot_file(input_path, output_path):
    color_map = {}
    last_key = None
    with open(input_path, 'r') as infile, open(output_path, 'w') as outfile:
        for line in infile:
            stripped = line.rstrip('\n')
            # Skip empty lines
            if not stripped.strip():
                outfile.write(line)
                continue
            # Skip lines ending with {, }, or ]
            if stripped.endswith('{') or stripped.endswith('}') or stripped.endswith(']'):
                outfile.write(line)
                continue
            # Find the key before ' -> '
            if '->' in stripped:
                key = stripped.split('->', 1)[0].strip()
                if key != last_key:
                    color = random_color()
                    color_map[key] = color
                    last_key = key
                else:
                    color = color_map.get(key, random_color())
                # Append color attribute
                if '[' in stripped:
                    # Already has attributes, append color
                    new_line = stripped.rstrip(']') + f', color=\"{color}\"]\n'
                else:
                    new_line = stripped + f' [color=\"{color}\"]\n'
                outfile.write(new_line)
            else:
                outfile.write(line)

if __name__ == "__main__":
    import sys
    # Usage: python converter.py [input_file] [output_file]
    input_file = sys.argv[1] if len(sys.argv) > 1 else "../graph.dot"
    output_file = sys.argv[2] if len(sys.argv) > 2 else "../graph_colored.dot"
    process_dot_file(input_file, output_file)

[seankhliao]

does color help when they all blend together as in your original image?

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