draw_mermaid_png() — langchain Function Reference

Architecture documentation for the draw_mermaid_png() function in graph_mermaid.py from the langchain codebase.

Function python LangChainCore Runnables calls 3 called by 1

Entity Profile

LangChainCore→ Runnables→ draw_mermaid_png() — langchain Function Reference

Dependency Diagram

graph TD
  affcc91c_bcd9_50c2_5762_c17c81886c6a["draw_mermaid_png()"]
  c545ef44_a033_15ff_e016_18af37277247["graph_mermaid.py"]
  affcc91c_bcd9_50c2_5762_c17c81886c6a -->|defined in| c545ef44_a033_15ff_e016_18af37277247
  e4ea941d_52a7_cfaa_e5e3_77cb8a320bf3["_render_mermaid_using_api()"]
  e4ea941d_52a7_cfaa_e5e3_77cb8a320bf3 -->|calls| affcc91c_bcd9_50c2_5762_c17c81886c6a
  f12768d7_87ad_702b_934f_217228b590c5["requests()"]
  affcc91c_bcd9_50c2_5762_c17c81886c6a -->|calls| f12768d7_87ad_702b_934f_217228b590c5
  bf3680e2_9ce5_0796_dd67_2a37f682c93b["_render_mermaid_using_pyppeteer()"]
  affcc91c_bcd9_50c2_5762_c17c81886c6a -->|calls| bf3680e2_9ce5_0796_dd67_2a37f682c93b
  e4ea941d_52a7_cfaa_e5e3_77cb8a320bf3["_render_mermaid_using_api()"]
  affcc91c_bcd9_50c2_5762_c17c81886c6a -->|calls| e4ea941d_52a7_cfaa_e5e3_77cb8a320bf3
  style affcc91c_bcd9_50c2_5762_c17c81886c6a fill:#6366f1,stroke:#818cf8,color:#fff

Relationship Graph

Source Code

libs/core/langchain_core/runnables/graph_mermaid.py lines 277–331

def draw_mermaid_png(
    mermaid_syntax: str,
    output_file_path: str | None = None,
    draw_method: MermaidDrawMethod = MermaidDrawMethod.API,
    background_color: str | None = "white",
    padding: int = 10,
    max_retries: int = 1,
    retry_delay: float = 1.0,
    base_url: str | None = None,
    proxies: dict[str, str] | None = None,
) -> bytes:
    """Draws a Mermaid graph as PNG using provided syntax.

    Args:
        mermaid_syntax: Mermaid graph syntax.
        output_file_path: Path to save the PNG image.
        draw_method: Method to draw the graph.
        background_color: Background color of the image.
        padding: Padding around the image.
        max_retries: Maximum number of retries (MermaidDrawMethod.API).
        retry_delay: Delay between retries (MermaidDrawMethod.API).
        base_url: Base URL for the Mermaid.ink API.
        proxies: HTTP/HTTPS proxies for requests (e.g. `{"http": "http://127.0.0.1:7890"}`).

    Returns:
        PNG image bytes.

    Raises:
        ValueError: If an invalid draw method is provided.
    """
    if draw_method == MermaidDrawMethod.PYPPETEER:
        img_bytes = asyncio.run(
            _render_mermaid_using_pyppeteer(
                mermaid_syntax, output_file_path, background_color, padding
            )
        )
    elif draw_method == MermaidDrawMethod.API:
        img_bytes = _render_mermaid_using_api(
            mermaid_syntax,
            output_file_path=output_file_path,
            background_color=background_color,
            max_retries=max_retries,
            retry_delay=retry_delay,
            base_url=base_url,
            proxies=proxies,
        )
    else:
        supported_methods = ", ".join([m.value for m in MermaidDrawMethod])
        msg = (
            f"Invalid draw method: {draw_method}. "
            f"Supported draw methods are: {supported_methods}"
        )
        raise ValueError(msg)

    return img_bytes