draw_mermaid_png() — langchain Function Reference

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

Function python LangChainCore Runnables calls 1

Entity Profile

LangChainCore→ Runnables→ draw_mermaid_png() — langchain Function Reference

Dependency Diagram

graph TD
  e151d2f1_d848_ea86_47fa_455730afbb7a["draw_mermaid_png()"]
  646f3bb5_a594_563e_cfbf_e18bdc9efb90["Graph"]
  e151d2f1_d848_ea86_47fa_455730afbb7a -->|defined in| 646f3bb5_a594_563e_cfbf_e18bdc9efb90
  b9f04a0f_6507_1a21_7a91_357a589c2c3a["draw_mermaid()"]
  e151d2f1_d848_ea86_47fa_455730afbb7a -->|calls| b9f04a0f_6507_1a21_7a91_357a589c2c3a
  style e151d2f1_d848_ea86_47fa_455730afbb7a fill:#6366f1,stroke:#818cf8,color:#fff

Relationship Graph

Source Code

libs/core/langchain_core/runnables/graph.py lines 630–703

    def draw_mermaid_png(
        self,
        *,
        curve_style: CurveStyle = CurveStyle.LINEAR,
        node_colors: NodeStyles | None = None,
        wrap_label_n_words: int = 9,
        output_file_path: str | None = None,
        draw_method: MermaidDrawMethod = MermaidDrawMethod.API,
        background_color: str = "white",
        padding: int = 10,
        max_retries: int = 1,
        retry_delay: float = 1.0,
        frontmatter_config: dict[str, Any] | None = None,
        base_url: str | None = None,
        proxies: dict[str, str] | None = None,
    ) -> bytes:
        """Draw the graph as a PNG image using Mermaid.

        Args:
            curve_style: The style of the edges.
            node_colors: The colors of the nodes.
            wrap_label_n_words: The number of words to wrap the node labels at.
            output_file_path: The path to save the image to. If `None`, the image
                is not saved.
            draw_method: The method to use to draw the graph.
            background_color: The color of the background.
            padding: The padding around the graph.
            max_retries: The maximum number of retries (`MermaidDrawMethod.API`).
            retry_delay: The delay between retries (`MermaidDrawMethod.API`).
            frontmatter_config: Mermaid frontmatter config.
                Can be used to customize theme and styles. Will be converted to YAML and
                added to the beginning of the mermaid graph.

                See more here: https://mermaid.js.org/config/configuration.html.

                Example config:

                ```python
                {
                    "config": {
                        "theme": "neutral",
                        "look": "handDrawn",
                        "themeVariables": {"primaryColor": "#e2e2e2"},
                    }
                }
                ```
            base_url: The base URL of the Mermaid server for rendering via API.
            proxies: HTTP/HTTPS proxies for requests (e.g. `{"http": "http://127.0.0.1:7890"}`).

        Returns:
            The PNG image as bytes.
        """
        # Import locally to prevent circular import
        from langchain_core.runnables.graph_mermaid import (  # noqa: PLC0415
            draw_mermaid_png,
        )

        mermaid_syntax = self.draw_mermaid(
            curve_style=curve_style,
            node_colors=node_colors,
            wrap_label_n_words=wrap_label_n_words,
            frontmatter_config=frontmatter_config,
        )
        return draw_mermaid_png(
            mermaid_syntax=mermaid_syntax,
            output_file_path=output_file_path,
            draw_method=draw_method,
            background_color=background_color,
            padding=padding,
            max_retries=max_retries,
            retry_delay=retry_delay,
            proxies=proxies,
            base_url=base_url,
        )