BPMN Diagrams Preprocessor for Foliant

BPMN (Business Process Modeling Notation) is visual modeling language for documenting business workflows. This preprocessor converts BPMN diagram definitions in source markdown files and converts them into images on the fly during project build.

This preprocessor uses bpmn-to-image tool by bpmn.io to convert diagrams into images.

Installation

$ pip install foliantcontrib.bpmn

You will also need to install bpmn-to-image:

$ npm install -g bpmn-to-image

Config

To enable the preprocessor, add bpmn to preprocessors section in the project config:

preprocessors:
    - bpmn

The preprocessor has a number of options:

preprocessors:
    - bpmn:
        cache_dir: !path .diagramscache/bpmn
        converter_path: bpmn-to-image
        format: png
        as_image: true
        params:
            no-title: true
        `fix_svg_size`: false

cache_dir : Path to the cache directory for the generated diagrams. It can be a path relative to the project root or a global one.

To save time during build, only new and modified diagrams are rendered. The generated images are cached and reused in future builds.

converter_path : Path to bpmn-to-image binary. By default, it is assumed that you have the bpmn-to-image command in your PATH, but if it is not the case you can define it here. Default: bpmn-to-image

format : Output format of the diagram image. Available formats at the time of writing: pdf, png, svg (note that most backends won't render pdf as image). Default: png

as_image : If true — inserts the diagram into the document as Markdown-image. If false — inserts the svg code of the diagram directly into the document (works only for svg format). Default: true

params : Params passed to the bpmn-to-image tool. Value of this option must be a YAML-mapping. Params which require values should be specified as param: value; params which don't require values should be specified as param: true:

    preprocessors:
        - bpmn:
            params:
                no-footer: true
                min-dimensions: '500x300'

To see the full list of available params, run the bpmn-to-image command without parameters.

fix_svg_size : Works only with svg format and as_image: false. By default svg is embedded with hardcoded width and height so they may exceed the boundaries of your HTML page. If this option is set to true the svg width and height will be set to 100% which will make it fit inside your content container. Default: false.

Usage

To insert a diagram definition in your Markdown source, enclose it between <bpmn>...</bpmn> tags:

Here’s the diagram:

<bpmn>
    <?xml version="1.0" encoding="UTF-8"?>
    <definitions xmlns="http://www.omg.org/spec/BPMN/20100524/MODEL" xmlns:bpmndi="http://www.omg.org/spec/BPMN/20100524/DI" xmlns:omgdc="http://www.omg.org/spec/DD/20100524/DC" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" id="sid-38422fae-e03e-43a3-bef4-bd33b32041b2" targetNamespace="http://bpmn.io/bpmn" exporter="http://bpmn.io" exporterVersion="0.10.1">
      <process id="Process_1" isExecutable="false">
        <task id="Task_0l0q2kz" name="Single Task" />
      </process>
      <bpmndi:BPMNDiagram id="BpmnDiagram_1">
        <bpmndi:BPMNPlane id="BpmnPlane_1" bpmnElement="Process_1">
          <bpmndi:BPMNShape id="Task_0l0q2kz_di" bpmnElement="Task_0l0q2kz">
            <omgdc:Bounds x="206" y="108" width="100" height="80" />
          </bpmndi:BPMNShape>
        </bpmndi:BPMNPlane>
      </bpmndi:BPMNDiagram>
    </definitions>
</bpmn>

You can override preprocessor parameters in the tag options. For example if the format for diagrams is set to png in foliant.yml and you need one of your diagrams to render in svg, override the format option in the tag:

SVG diagram:

<bpmn format="svg">
...
</bpmn>

Tags also have an exclusive option caption — the markdown caption of the diagram image.

Diagram with a caption:

<bpmn caption="Diagram of the supply process">
...
</bpmn>