[FEAT] Detect and Render Multi-instance Marker of Pool

[csouchet]

Here is a BPMN diagram containing an horizontal pool with a multi-instance marker

<?xml version="1.0" encoding="UTF-8"?>
<bpmn:definitions xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
        xmlns:bpmn="http://www.omg.org/spec/BPMN/20100524/MODEL"
        xmlns:bpmndi="http://www.omg.org/spec/BPMN/20100524/DI"
        xmlns:dc="http://www.omg.org/spec/DD/20100524/DC"
        id="Definitions_1ww22xr" targetNamespace="http://bpmn.example.com">
  <bpmn:collaboration id="Collaboration_0dpe47f">
    <bpmn:participant id="Participant_11969lb" processRef="Process_0rlrq34">
      <bpmn:participantMultiplicity maximum="3"/>
    </bpmn:participant>
  </bpmn:collaboration>
  <bpmn:process id="Process_0rlrq34" isExecutable="false" />
  <bpmndi:BPMNDiagram id="BPMNDiagram_1">
    <bpmndi:BPMNPlane id="BPMNPlane_1" bpmnElement="Collaboration_0dpe47f">
      <bpmndi:BPMNShape id="Participant_11969lb_di" bpmnElement="Participant_11969lb" isHorizontal="true">
        <dc:Bounds x="156" y="61" width="600" height="250" />
      </bpmndi:BPMNShape>
    </bpmndi:BPMNPlane>
  </bpmndi:BPMNDiagram>
</bpmn:definitions>

The Nobel Prize Process.bpmn diagram taken from the BPMN Specification examples also contains such pools.

Notes for implementation

We currently use a standard mxGraph shape (swimlane) to render the pool. A new dedicated shape will be required to support the marker rendering. The marker is already used in activities and should be reused.

Please start a discussion prior starting the implementation for guidance or help.

⚠️ Check the contribution guidelines for BPMN support