0.6.0 - 2026-05-28

Release Notes

This release adds an opt-in SVG output pipeline for applications that need Mermaid-parity SVG by default but also need cleaner output for in-app previews, PNG/PDF export, or host-specific theming. Use render_svg_sync for parity snapshots, SvgPipeline::readable() when the SVG will be inlined and should keep readable fallback text, and SvgPipeline::resvg_safe() before rasterizing through resvg / usvg.

Added

• Added SvgPipeline::readable() and SvgPipeline::resvg_safe() for callers that need fallback text, rasterizer-friendly SVG, or cleanup without changing default render_svg_sync output.

• Added host styling extension points: SvgPostprocessor for custom passes, ScopedCssPostprocessor for CSS injection, and CssOverridePolicy::StripExistingImportant for callers that want app styles to override Mermaid defaults. Postprocessors can read the diagram type, title, and root SVG id from SvgPostprocessContext.

• Expanded Zed-derived regression coverage for Sequence, Flowchart, ER, Gantt, Class, and raster fallback cases.

• Added crate-specific README pages for merman-core, merman-render, and merman-cli, including focused parsing, rendering, and CLI examples for docs.rs/crates.io users.

• Added a rendering guide in docs/rendering/SVG_OUTPUT_PIPELINE.md and a runnable svg_pipeline example:

  cargo run -p merman --features render --example svg_pipeline < fixtures/flowchart/basic.mmd > out.svg

  Library integrations can use the same pipeline directly. This example builds a typical editor/export pipeline: make the SVG resvg-friendly, allow host CSS to override Mermaid defaults, and scope the injected CSS to one diagram id.

  use merman::render::{
      CssOverridePolicy, HeadlessRenderer, ScopedCssPostprocessor, SvgPipeline,
  };
  
  let pipeline = SvgPipeline::resvg_safe().with_postprocessor(
      ScopedCssPostprocessor::new(
          r#"
  .node rect {
    stroke: #2563eb;
    stroke-width: 2px;
  }
  .merman-foreignobject-fallback-text {
    fill: #111827;
  }
  "#,
      )
      .with_override_policy(CssOverridePolicy::StripExistingImportant),
  );
  let renderer = HeadlessRenderer::new().with_diagram_id("host-diagram");
  let svg = renderer
      .render_svg_with_pipeline_sync("flowchart TD; A[API]-->B[DB];", &pipeline)?
      .unwrap();
  # let _ = svg;
  # Ok::<(), Box<dyn std::error::Error>>(())

Changed

• Readable SVG helpers, raster helpers, and CLI raster export now use the shared SVG output pipeline; default render_svg_sync remains Mermaid-parity output with no consumer cleanup.
• ScopedCssPostprocessor now inserts host CSS after existing SVG styles when possible, so scoped host rules follow Mermaid defaults in cascade order.

Fixed

• Fixed Architecture arrowheads on diagonal edges so they follow the rendered line direction.
• Fixed readable/raster output for Mermaid HTML labels: fallback text now handles literal \n, avoids double-escaped entities such as class generics, and keeps useful styling context for host CSS.
• Fixed sequence diagrams with keyword-like participant ids such as AS, END, RECT, or loop.
• Hardened SvgPipeline::resvg_safe() against common usvg / resvg incompatibilities, including unsupported CSS, animation declarations, invalid visual attributes, empty rectangle placeholders, CSS deg units, and non-finite values.

Install merman-cli 0.6.0

Install prebuilt binaries via shell script

curl --proto '=https' --tlsv1.2 -LsSf https://github.com/Latias94/merman/releases/download/v0.6.0/merman-cli-installer.sh | sh

Install prebuilt binaries via powershell script

powershell -ExecutionPolicy Bypass -c "irm https://github.com/Latias94/merman/releases/download/v0.6.0/merman-cli-installer.ps1 | iex"

Download merman-cli 0.6.0

File	Platform	Checksum
merman-cli-aarch64-apple-darwin.tar.xz	Apple Silicon macOS	checksum
merman-cli-x86_64-apple-darwin.tar.xz	Intel macOS	checksum
merman-cli-x86_64-pc-windows-msvc.zip	x64 Windows	checksum
merman-cli-x86_64-unknown-linux-gnu.tar.xz	x64 Linux	checksum