Crate flowmaid 

flowmaid — a Mermaid-like diagram engine.

Supported diagram types: flowcharts (flowchart / graph), Entity-Relationship diagrams (erDiagram), UML class diagrams (classDiagram), sequence diagrams (sequenceDiagram), pie charts (pie), state diagrams (stateDiagram-v2), mindmaps (mindmap), and user-journey diagrams (journey).

Library usage:

let svg = flowmaid::render_svg("flowchart TD\nA[Start] --> B[Done]").unwrap();
assert!(svg.starts_with("<svg"));

let er = flowmaid::render_svg("erDiagram\nusers ||--o{ posts : writes").unwrap();
assert!(er.contains("users"));

let uml = flowmaid::render_svg("classDiagram\nAnimal <|-- Dog").unwrap();
assert!(uml.contains("Animal"));

Re-exports

pub use emit::to_mermaid;

pub use model::Document;

pub use parser::ParseError;

Modules

class

UML class diagram rendering: classes drawn as three-compartment boxes (name / fields / methods), relationships drawn with UML end glyphs (triangles, diamonds, open arrows).

emit

Graph → mermaid text — the inverse of crate::parser::parse (issue #18).

er

Entity-Relationship rendering: entities drawn as attribute tables, relationships drawn with crow’s foot notation.

fold

Serpentine / compact layout for long linear chains (issue #15).

journey

User-journey rendering: a fixed horizontal band — no graph layout. Tasks flow left to right in source order; each is a smiley face whose color and mouth curve track its 1–5 satisfaction score (red frown → green smile). Sections are colored bands spanning their tasks, a thin path links the faces, and each participant gets a stable accent shown in a legend and as per-task dots.

layout

Sugiyama layout engine, following dagre (the algorithm mermaid.js uses):

mindmap

Mindmap rendering, in the Mermaid style: the root sits at the centre and branches radiate outward. Nodes at depth k land on a ring of radius k · RING; each subtree owns an angular wedge sized by its leaf count, so busy branches get more room. Every top-level branch gets a stable accent that its whole subtree fills, and the six node shapes (rounded / square / circle / hexagon / bang / cloud) are drawn for real.

model

Core data model: graph, nodes, edges.

parser

Hand-written parser for Mermaid-like diagram syntax.

pie

Pie chart rendering: proportional slices drawn clockwise from 12 o’clock, percentage labels inside the slices, and a color legend on the right (with raw values when showData is set).

render

SVG wrapper: render(graph) = automatic scene -> SVG serialisation. All geometry & serialisation logic lives in the scene module, so the output of render() and the interactive flow (scene/route/to_svg) are guaranteed identical.

scene

Ready-to-draw geometry for interactive apps (drag & drop editors, hit-testing, export). Every coordinate in this module is FINAL (screen pixels, already following the diagram direction) — unlike the abstract coordinates inside layout.

seq

Sequence diagram rendering: participant boxes across the top, dashed lifelines below, and one row per statement top-down.

style

Shared color theme, exposed so hosts (GUI painters) can match the SVG writers exactly.

Functions

render_svg

Shortcut: Mermaid-syntax text -> SVG string. Dispatches on the diagram type header (flowchart/graph, erDiagram, classDiagram, sequenceDiagram, pie, or stateDiagram-v2).