Diaview

Diaview is a terminal-native diagram renderer for Mermaid flowcharts. It parses a supported Mermaid flowchart subset, lays it out in Rust, and renders it with Ratatui.

Current scope

Supported today:

• graph TD
• graph TB normalized to top-down
• graph LR
• flowchart TD
• flowchart LR
• rectangle nodes: A[text]
• rounded nodes: A(text)
• diamond nodes: A{text}
• circle nodes: A((text))
• database/cylinder nodes: A[(text)]
• bare node refs: A
• solid arrows: -->
• solid links without arrows: ---
• dashed arrows: -.->
• dashed links without arrows: -.-
• thick arrows: ==>
• edge labels: -->|text| and -- text -->
• subgraph blocks with ids, labels, and membership
• whole-line comments starting with %%
• semicolon-separated statements

Not supported yet:

• interactive editing or selection
• agent / Visual REPL features
• class/style declarations
• non-flowchart Mermaid diagram types
• Graphviz / dagre-backed layout
• general-purpose Mermaid syntax coverage

Usage

Render fullscreen from a file:

cargo run -- fixtures/simple.mmd

Render inline from a file:

cargo run -- --inline fixtures/simple.mmd

Render inline from stdin:

cat fixtures/simple.mmd | cargo run -- --inline

License

Diaview is dual-licensed under either MIT or Apache-2.0.

Font requirement

Diaview requires Nerd Fonts v3 glyph support.

Use a patched Nerd Font, or install Symbols Nerd Font Mono as a terminal fallback.

On macOS with Homebrew:

brew install --cask font-symbols-only-nerd-font

Development

cargo fmt --check
cargo check
cargo test
cargo run -- --inline fixtures/complex_architecture.mmd

Current limitations

• terminal-native rendering only
• no fullscreen interaction yet
• no hidden layout engine dependency
• no raster / Kitty graphics output
• parser and layout support are intentionally narrow

Docs

• docs/README.md
• docs/architecture.md
• docs/development.md
• docs/parser.md
• docs/layout.md
• docs/rendering.md
• docs/testing.md
• docs/roadmap.md