Crate limu 

limu reads Mermaid diagrams and lays them out, for programs that draw them themselves: in a window, in a terminal, as SVG.

A diagram goes through three stages. Parsing reads the diagram’s text into a model of it. Layout places the model’s parts, measuring text with a measurer the host gives, into a scene, which says what each part is and where it is, but not how it looks. A backend draws the scene, settling its colors from a style’s look. Style is not layout, so a scene is drawn in any theme without being laid out again.

Much of limu is ported from Pele, the Mermaid renderer of the Obsidian team, and its tests compare what limu does with what Pele does, number for number.

Re-exports

pub use limu_scene as scene;

Modules

layout

What a layout takes besides the diagram: what changes where things are. A change of these lays a diagram out again, where a change of style does not.

roles

The roles of the items limu lays out, by the diagram they are of, as “flowchart.node”. A host styles items by role, keying Look::overrides by these names, and a host that draws items its own way tells them apart by role, as an item’s Role equals the name it has.

Structs

Diagram

A diagram’s text read into a model, ready to be laid out. Laying it out changes neither its model nor its configuration, so one diagram may be laid out many times, with other options, and from many threads at once. A host that lays a diagram out again when its width changes parses it once.

Error

An error in a diagram’s text, as Pele’s PeleError is.

Map

An object’s keys and values, in the order JavaScript gives an object’s keys: those that are array indices, “0” to “4294967294” written without leading zeros, in numeric order, and then the rest in the order they were first set.

ParseOptions

What a diagram’s text is read with, as Pele’s ParseOptions has it.

Enums

DiagramType

A type of diagram, as Pele names it.

ErrorCode

What kind of error an Error is, as Pele’s PeleErrorCode says.

Value

A value of a diagram’s configuration: one of JSON’s kinds of value, as JavaScript holds it once JSON.parse or a YAML reader has read it.

Constants

DEFAULT_LIMIT

The most UTF-16 code units a diagram’s text may have by default, Mermaid’s maxTextSize. It is how long the text may be, counted as JavaScript counts a string’s length.

DEFAULT_MAX_EDGES

The most edges a flowchart or an agent flow may have by default. Mermaid stops at 500. Pele draws 5,000 in tens of milliseconds, and A & B --> C & D multiplies, so that without a limit a few kilobytes of text ask for millions of edges.

Functions

layout

Reads a diagram’s text and lays it out as a scene, for a backend to draw: parse with the default limits and no configuration of the host’s, and then Diagram::layout. Its errors are theirs.

parse

Reads a diagram’s text, as Pele’s parse does: its front matter and directives, its type, and then its body, with the parser of its type. The options hold the limits the text is held to and the configuration beneath its own. What changes where things are is given to Diagram::layout. Its errors are text of no type limu reads, text it cannot parse, and text past a limit. An error found once the type is known holds it, as Pele’s tagErrors gives it, and so do the errors of layout.

supports

Whether limu reads the type of diagram a text is, as Pele’s supports says: its type is found, and it is one limu reads. Text whose front matter does not read is not supported. It does not parse the diagram, which may still be in error.

types

The types of diagram limu reads, in the order Pele’s registry lists them. Each is a feature of the crate, and only those it is built with are here.