MerGram

Programmatically generate Mermaid diagrams and charts using Python.

MerGram currently supports constructing Mermaid flowcharts, with plans to expand support for additional diagram and chart types in future releases.

Features

• Build Mermaid flowcharts using Python classes
• Support for nodes, links, and subgraphs, and style assignments
• Export diagrams to Mermaid .mmd or .mermaid files
• Optional integration with networkx for graph conversion

What's New in

v0.3.0

• Style class that can be used to add style ... lines to flowcharts
• Fixes to style-related outputs for nodes

v0.2.0

• Flowchart.to_markdown function to get a string representation of the flowchart embedded in a Markdown Mermaid code block.
• Flowchart.to_html function to get a string representation of the flowchart embedded in HTML.

Installation

pip install mergram

To enable networkx integration:

pip install mergram[networkx]

Usage

Basic Flowchart

from mergram.flowchart import Flowchart, Node, Link

fc = Flowchart("Example Flowchart")
a = Node("A", label="Start")
b = Node("B", label="End", shape='circle')
fc += a
fc += b
fc += Link(a, b, text="to end")

print(fc)

Generates the following mermaid diagram code:

---
title: Example Flowchart
---
flowchart TB
    A@{ shape: rect, label: Start }
    B@{ shape: circle, label: End }
    A-->|to end|B
    style A fill:#fff, stroke:#000, stroke-width:2px, color:#000
    style B fill:#fff, stroke:#000, stroke-width:2px, color:#000

That looks like:

---
 title: Example Flowchart
---
flowchart TB
    A@{ shape: rect, label: Start }
    B@{ shape: circle, label: End }
    A-->|to end|B
    style A fill:#fff, stroke:#000, stroke-width:2px, color:#000
    style B fill:#fff, stroke:#000, stroke-width:2px, color:#000

From NetworkX

import networkx as nx
from mergram.flowchart import Flowchart

G = nx.DiGraph()
G.add_edge("A", "B", label="to B")
G.add_edge("B", "A", label="to A")
fc = Flowchart("From NetworkX", orientation='LR')
fc.from_networkx(G)
print(fc)

---
title: From NetworkX
---
flowchart LR
    B@{ shape: rect, label: B }
    A@{ shape: rect, label: A }
    A-->|to B|B
    B-->|to A|A
    style A fill:#fff, stroke:#000, stroke-width:2px, color:#000
    style B fill:#fff, stroke:#000, stroke-width:2px, color:#000

---
 title: From NetworkX
---
flowchart LR
    B@{ shape: rect, label: B }
    A@{ shape: rect, label: A }
    A-->|to B|B
    B-->|to A|A
    style A fill:#fff, stroke:#000, stroke-width:2px, color:#000
    style B fill:#fff, stroke:#000, stroke-width:2px, color:#000

Export to File

fc.write("diagram.mmd")

Optional Dependencies

• networkx: For converting existing graphs to Mermaid flowcharts.

License

MIT License

Contributing

Contributions are welcome! Please open issues or pull requests.