mermaid_core 0.3.0

Pure Dart port of mermaid.js: detect, parse and lay out 28 diagram types into a backend-agnostic scene, with an SVG renderer and a CLI. No Flutter.

0.3.0

• Honor active per-diagram layout and style configuration through init directives and frontmatter, including nested flow collections. See the configuration support notes in parity/ for backend and upstream limitations.

• Use the effective upstream ER cell padding default of 20 and allow overrides.

• Parse CSS named colors, HSL/HSLA, percentage RGB and alpha forms, with finite numeric validation and channel clamping.

• Honor Kanban ticket URLs and all radar margins. Keep Cynefin boundary randomness within 32-bit arithmetic on the Dart VM.

• Add registered Kanban task icons, task styles, and interaction directives.

• Apply requirement element styles and interaction directives.

• Correct right-to-left Git graph layout and adjacent class-note placement.

• Require ELK 0.2.0 for corrected compound routes, ports, labels, loops, spacing, and layout strategy handling.

0.2.1

• Version alignment with mermaid_flutter 0.2.1. No code changes.

0.2.0

Behavior changes

• Scene groups now carry a SceneGroupRole. RenderScene.nodeBounds and node hit-testing include only SceneGroupRole.node groups, so cluster, frame, namespace, boundary, section, and legend ids are no longer reported as nodes.
• MermaidTheme equality and hashCode now cover every palette field instead of the 16 base fields, so two themes that differ only in a palette no longer compare equal.
• Default cScale*, cScaleInv*, and cScalePeer* colors now match Mermaid.js 11, and forestTheme defines an XY chart plot palette.
• Multi-line subgraph titles (subgraph S["a<br/>b"]) now sit inside the cluster border instead of above it; the cluster reserves the full title band.
• Frontmatter config: YAML now strips trailing # comments, so width: 800 # note reads as the number 800 instead of silently falling back to the default. As in YAML, an unquoted value that starts with # is a comment, so quote color literals such as linkColor: '#ff0000'.
• Frontmatter config keys may contain hyphens and dots, and values accept flow-style maps such as nodeColors: {Bio-conversion: '#f00'}.
• layoutSankey takes a single config: SankeyConfig parameter instead of twelve named options. Mermaid.render is unaffected.
• SankeyConfig.useMaxWidth was removed; it was parsed but never read.
• XyChart.horizontal, showDataLabel, and showDataLabelOutsideBar are now getters over XyChart.config; the matching constructor parameters were removed.

Changes

• Add resolveDiagramConfig for reading per-diagram configuration from directives and frontmatter.
• Honor common layout configuration for sequence, flowchart, state, class, Gantt, pie, and gitGraph diagrams through directives and frontmatter.
• Add SceneShape.copyWith and SceneText.copyWith, and value equality on SceneEdgeMetadata.
• Compute RenderScene.nodeBounds once per scene and reuse the map, and make MermaidTheme equality short-circuit on identity with a cached hash code.
• Share edge geometry helpers (rect intersection, basis curves, path midpoints) and validated config readers across diagram layouts.
• Add scene-space node-bound lookup through RenderScene.nodeBounds and RenderScene.boundsOfNode.
• Add structured flowchart edge metadata and path-distance measurement for precise stroke and label interaction.
• Add paint-only flowchart node and link overrides that reuse an existing parsed and laid-out scene.
• Document and verify deterministic Dagre, ELK, and hand-drawn flowchart geometry, including geometry-preserving style changes.
• Wrap long flowchart labels at spaces, underscores, and hyphens before using hard character breaks.
• Place long flowchart edge labels at the midpoint of the routed path and adjust them away from node collisions.
• Honor Sankey frontmatter for dimensions, alignment, values, prefixes, suffixes, node colors, link colors, and label styles.
• Improve Sankey node ordering and link composition, and keep small node bars and gradient lanes visible at a consistent minimum thickness.
• Honor XY chart theme and layout configuration, including horizontal charts, data labels, plot spacing, axis typography, and stroke widths.
• Align quadrant dimensions, padding, quoted axis labels, trailing arrows, and rotated axes with the configured viewport.
• Improve nested state placement, fills, and routing, including states that are referenced before their composite declaration.
• Improve sequence participant sizing, note wrapping, activation alignment, side-note clearance, autonumber badges, frame layout, and nested rect paint order.
• Improve class, flowchart, C4, and requirement graph routing, edge-label clearance, relation markers, and dense-node ordering.
• Center titled flowchart subgraphs on their member rows, keep block arrowheads outside adjacent nodes, and align Git graph commit labels and tag notches with Mermaid.js.
• Correct ER entity spacing, Gantt paint order, Journey label contrast, Timeline section spans, Ishikawa label and arrow alignment, and Radar labels.
• Align Venn labels, treemap squarification, spanning block groups, C4 deployment boundaries, and the default Mermaid color scale with Mermaid.js.
• Include all diagram palettes and specialized color roles in MermaidTheme.copyWith, equality, and hash-code calculations.
• Preserve hand-drawn edge markers and legacy Font Awesome labels, and add gradient strokes and multiply compositing to render scenes and SVG output.

Fixes

• Header-only diagrams (flowchart TB, classDiagram, erDiagram, requirementDiagram, stateDiagram-v2) render an empty scene instead of throwing from render().
• A sequence block with no participants, a transition into an empty composite state, and a quadrant chart smaller than its title and axis bands render instead of throwing.
• Sankey values too large to scale (such as 1e308) no longer throw; NaN and the infinities are reported as a MermaidParseException at parse time.
• look: handDrawn keeps gradient link colors and multiply blending instead of flattening them to a solid color.
• Long flowchart edge labels, flowchart titles, and isolated-direction subgraph titles carry explicit line breaks, so SVG output no longer overflows its label box.
• Block: a child's span is clamped to its group's column count so a wide span no longer paints over siblings, and round shapes are sized from the shorter side of their cell.
• C4: boundary descriptions are measured at the width they are drawn at, so a long description no longer paints over the elements inside the boundary; an empty boundary label reserves no space.
• Class: cross-namespace relations follow direction, relation labels use the theme's edge-label background, namespace separation repeats until no clusters overlap, and notes move with their class.
• Git: the LR commit-tag spear tip is drawn outside the tag body, matching upstream.
• Venn: the title band is sized from the measured title so it no longer overlaps the circles.
• ER: attribute bands grow with the minimum-height floor so they cover the whole entity.
• Requirement: the re-column pass is bounded by each rank's free space, so a relation source no longer drags its target past its neighbours.
• XY chart: negative, zero, or non-finite config.xyChart dimensions fall back to defaults; an all-equal value series maps to the middle of the range and a single category is centered, matching d3.
• Sankey: a node with a custom nodeColors entry no longer consumes a palette slot, and value-less labels are centered on their node.
• Sequence: a created participant's top box is exposed as actor_<id> again, and message arrowheads stop on the target's activation bar.
• Radar: a body title line overrides the frontmatter title, matching every other diagram.
• Quadrant: a dangling axis label appends the long arrow with surrounding spaces, matching upstream's grammar.
• Journey section labels use the theme's title color; Ishikawa cause labels are centered on their box.

0.1.2

• Route flowchart edges into subgraphs with bends that more closely match Mermaid.js.
• Prevent command and read-model nodes from overlapping in Event Modeling diagrams.
• Align Kanban section titles, card insets, and bottom padding with Mermaid.js.
• Render C4 database cylinders without a white cutout in the top cap.

0.1.1

• Prevent late font fallback changes on Flutter web from wrapping flowchart labels outside their node boxes.

0.1.0

Initial release. Pure Dart port of mermaid.js.

• 28 diagram types: flowchart, sequence, class, state, ER, pie, gantt, quadrant, journey, timeline, xychart, mindmap, requirement, C4, gitGraph, sankey, packet, block, radar, treemap, kanban, architecture, cynefin, venn, ishikawa, wardley, eventModeling, railroad.
• Diagram detection, hand-written parsers, layout (vendored dagre for graph diagrams; elk and tidy-tree alternate engines), and a backend-agnostic render scene IR.
• SVG renderer (renderSceneToSvg) and a CLI (mermaid_dart) that emits SVG, or PNG via an external rasterizer.
• Theme directives: %%{init}%% + frontmatter config.theme/themeVariables; named themes default/dark/forest/neutral.
• Hand-drawn look (look: handDrawn) — a faithful roughjs port.
• Icons on flowchart nodes via iconify-style packs (@{ icon: }).
• Math in labels ($$...$$): a TeX subset (super/subscripts, \frac, \sqrt, matrices, cases, braces, accents) laid out with scene primitives.
• Validated against 184 upstream demo fixtures.