DOC: Add open source diagram tooling

.gitignore

@@ -4,6 +4,7 @@ docs/_downloads
 docs/jupyter_execute/*
 docs/.jupyter_cache/*
 docs/reference
+docs/diagrams/build
 output
 
 *.log

docs/diagrams/.gitignore

@@ -0,0 +1,2 @@
+# Ignore the built diagrams
+build

docs/diagrams/config.toml

@@ -0,0 +1,14 @@
+# Configuration file for diagram generation using Kroki
+# Each [[diagram]] entry represents a diagram to be generated
+
+# Example Excalidraw diagram configuration
+# [[diagram]]
+# file_src = "src/example.excalidraw"
+# output_name = "example"
+# format = "svg"
+
+# Add your diagram configurations below
+[[diagram]]
+file_src = "src/indexing-parcels.excalidraw"
+output_name = "indexing-parcels"
+format = "svg"

docs/diagrams/main.py

@@ -0,0 +1,157 @@
+#!/usr/bin/env python
+"""
+Script to generate diagrams from source files using Kroki.
+
+This script reads configuration from config.toml and processes diagram files
+using the kroki CLI tool to generate output images.
+"""
+
+import subprocess
+import sys
+from pathlib import Path
+from typing import Literal
+
+from pydantic import BaseModel, Field, field_validator
+
+try:
+    import tomllib
+except ImportError:
+    import tomli as tomllib
+
+
+# Supported diagram types in Kroki
+DiagramType = Literal[ "actdiag", "blockdiag", "bpmn", "bytefield", "c4plantuml", "d2", "diagramsnet", "ditaa", "erd", "excalidraw", "graphviz", "mermaid", "nomnoml", "nwdiag", "packetdiag", "pikchr", "plantuml", "rackdiag", "seqdiag", "structurizr", "svgbob", "umlet", "vega", "vegalite", "wavedrom"]  # fmt: skip
+
+# Supported output formats
+OutputFormat = Literal["base64", "jpeg", "pdf", "png", "svg"]
+
+
+class DiagramConfig(BaseModel):
+    """Configuration for a single diagram."""
+
+    file_src: str = Field(
+        ..., description="Path to the source diagram file, relative to the script"
+    )
+    output_name: str | None = Field(
+        None, description="Output filename without extension (defaults to input stem)"
+    )
+    format: OutputFormat = Field("svg", description="Output format")
+    type: DiagramType | None = Field(
+        None, description="Diagram type (defaults to infer from file extension)"
+    )
+
+    @field_validator("file_src")
+    @classmethod
+    def validate_file_src(cls, v: str) -> str:
+        """Ensure file_src is not empty."""
+        if not v or not v.strip():
+            raise ValueError("file_src cannot be empty")
+        return v
+
+
+class Config(BaseModel):
+    """Root configuration model."""
+
+    diagram: list[DiagramConfig] = Field(
+        default_factory=list, description="List of diagrams to generate"
+    )
+
+
+def main():
+    """Main function to process diagrams based on config.toml."""
+    script_dir = Path(__file__).parent
+    config_file = script_dir / "config.toml"
+    build_dir = script_dir / "build"
+
+    # Ensure build directory exists
+    build_dir.mkdir(parents=True, exist_ok=True)
+
+    # Load configuration
+    try:
+        with open(config_file, "rb") as f:
+            config_data = tomllib.load(f)
+    except FileNotFoundError:
+        print(f"Error: Configuration file not found: {config_file}", file=sys.stderr)
+        sys.exit(1)
+    except Exception as e:
+        print(f"Error reading configuration file: {e}", file=sys.stderr)
+        sys.exit(1)
+
+    # Validate configuration with Pydantic
+    try:
+        config = Config(**config_data)
+    except Exception as e:
+        print(f"Error: Invalid configuration: {e}", file=sys.stderr)
+        sys.exit(1)
+
+    # Check if there are any diagrams configured
+    if not config.diagram:
+        print("No diagrams configured in config.toml")
+        return
+
+    print(f"Processing {len(config.diagram)} diagram(s)...")
+
+    # Process each diagram
+    for i, diagram in enumerate(config.diagram, 1):
+        # Get input file path (relative to script directory)
+        input_file = script_dir / diagram.file_src
+        if not input_file.exists():
+            print(
+                f"Warning: Source file not found: {input_file}, skipping",
+                file=sys.stderr,
+            )
+            continue
+
+        # Get output configuration
+        output_name = diagram.output_name or input_file.stem
+        output_format = diagram.format
+        output_file = build_dir / f"{output_name}.{output_format}"
+
+        # Detect diagram type from file extension or use explicit type
+        if diagram.type:
+            diagram_type = diagram.type
+        else:
+            # Infer from file extension
+            diagram_type = input_file.suffix.lstrip(".")
+            if diagram_type == "excalidraw":
+                diagram_type = "excalidraw"
+
+        # Build kroki command
+        cmd = [
+            "kroki",
+            "convert",
+            str(input_file),
+            "--type",
+            diagram_type,
+            "--format",
+            output_format,
+            "--out-file",
+            str(output_file),
+        ]
+
+        # Execute kroki command
+        print(
+            f"  [{i}/{len(config.diagram)}] Processing {diagram.file_src} -> {output_file.name}"
+        )
+        try:
+            result = subprocess.run(cmd, capture_output=True, text=True, check=True)
+            if result.stdout:
+                print(f"    {result.stdout.strip()}")
+        except subprocess.CalledProcessError as e:
+            print(
+                f"    Error processing {diagram.file_src}: {e.stderr.strip()}",
+                file=sys.stderr,
+            )
+            continue
+        except FileNotFoundError:
+            print(
+                "Error: 'kroki' command not found. Please ensure kroki is installed.",
+                file=sys.stderr,
+            )
+            sys.exit(1)
+
+    print("Done!")
+
+
+if __name__ == "__main__":
+    main()