feat(resize): snap to minimum bounds during resize

closes #252

lib/features/snapping/BpmnSnapping.js

@@ -5,6 +5,7 @@ var inherits = require('inherits');
 var forEach = require('lodash/collection/forEach');
 
 var getBoundingBox = require('diagram-js/lib/util/Elements').getBBox;
+var is = require('../modeling/ModelingUtil').is;
 
 var Snapping = require('diagram-js/lib/features/snapping/Snapping'),
     SnapUtil = require('diagram-js/lib/features/snapping/SnapUtil');
@@ -119,6 +120,24 @@ function BpmnSnapping(eventBus, canvas) {
       snapParticipant(participantSnapBox, shape, event);
     }
   });
+
+  eventBus.on('resize.start', 1500, function(event) {
+    var context = event.context,
+        shape = context.shape;
+
+    if (is(shape, 'bpmn:SubProcess')) {
+        context.minDimensions = { width: 140, height: 120 };
+    }
+
+    if (is(shape, 'bpmn:Participant')) {
+        context.minDimensions = { width: 400, height: 200 };
+    }
+
+    if (is(shape, 'bpmn:TextAnnotation')) {
+      context.minDimensions = { width: 50, height: 50 };
+    }
+  });
+  
 }
 
 inherits(BpmnSnapping, Snapping);

test/fixtures/bpmn/collaboration-resize.bpmn

@@ -0,0 +1,33 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<bpmn:definitions xmlns:bpmn="http://www.omg.org/spec/BPMN/20100524/MODEL" xmlns:bpmndi="http://www.omg.org/spec/BPMN/20100524/DI" xmlns:di="http://www.omg.org/spec/DD/20100524/DI" xmlns:dc="http://www.omg.org/spec/DD/20100524/DC" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" id="Definitions_1" targetNamespace="http://bpmn.io/schema/bpmn">
+  <bpmn:collaboration id="Collaboration_1">
+    <bpmn:participant id="Participant_1" processRef="Process_1" />
+    <bpmn:participant id="Participant_2" processRef="Process_2" />
+  </bpmn:collaboration>
+  <bpmn:process id="Process_1" isExecutable="false" />
+  <bpmn:process id="Process_2">
+    <bpmn:subProcess id="SubProcess_1" />
+    <bpmn:textAnnotation id="TextAnnotation_1" />
+    <bpmn:association id="Association_1" sourceRef="SubProcess_1" targetRef="TextAnnotation_1" />
+  </bpmn:process>
+  <bpmndi:BPMNDiagram id="BPMNDiagram_1">
+    <bpmndi:BPMNPlane id="BPMNPlane_1" bpmnElement="Collaboration_1">
+      <bpmndi:BPMNShape id="Participant_1_di" bpmnElement="Participant_1">
+        <dc:Bounds x="14" y="10" width="600" height="300" />
+      </bpmndi:BPMNShape>
+      <bpmndi:BPMNShape id="Participant_2_di" bpmnElement="Participant_2">
+        <dc:Bounds x="14" y="341" width="603" height="332" />
+      </bpmndi:BPMNShape>
+      <bpmndi:BPMNShape id="SubProcess_1_di" bpmnElement="SubProcess_1" isExpanded="true">
+        <dc:Bounds x="103" y="424" width="350" height="200" />
+      </bpmndi:BPMNShape>
+      <bpmndi:BPMNShape id="TextAnnotation_1_di" bpmnElement="TextAnnotation_1">
+        <dc:Bounds x="492" y="372" width="100" height="80" />
+      </bpmndi:BPMNShape>
+      <bpmndi:BPMNEdge id="Association_1_di" bpmnElement="Association_1">
+        <di:waypoint xsi:type="dc:Point" x="453" y="465" />
+        <di:waypoint xsi:type="dc:Point" x="492" y="429" />
+      </bpmndi:BPMNEdge>
+    </bpmndi:BPMNPlane>
+  </bpmndi:BPMNDiagram>
+</bpmn:definitions>

test/spec/features/snapping/BpmnSnappingSpec.js

@@ -10,6 +10,7 @@ var coreModule = require('../../../../lib/core'),
     snappingModule = require('../../../../lib/features/snapping'),
     modelingModule = require('../../../../lib/features/modeling'),
     createModule = require('diagram-js/lib/features/create'),
+    resizeModule = require('diagram-js/lib/features/resize'),
     rulesModule = require('../../../../lib/features/modeling/rules');
 
 var pick = require('lodash/object/pick');
@@ -165,4 +166,58 @@ describe('features/snapping - BpmnSnapping', function() {
 
   });
 
+  
+  describe('on shape resize', function () {
+    var diagramXML = require('../../../fixtures/bpmn/collaboration-resize.bpmn');
+    
+    var testResizeModules = [ coreModule, resizeModule, rulesModule, snappingModule ];
+
+    beforeEach(bootstrapModeler(diagramXML, { modules: testResizeModules }));
+
+    var createEvent;
+
+    beforeEach(inject(function(canvas, dragging) {
+      createEvent = Events.scopedCreate(canvas);
+    }));
+
+
+    it('should snap a SubProcess to minimum bounds', inject(function(canvas, elementRegistry, resize, dragging) {
+      
+      var subProcess = elementRegistry.get('SubProcess_1');
+
+      resize.activate(Events.create(canvas._svg, { x: 453, y: 624 }), subProcess, 'se');
+      dragging.move(Events.create(canvas._svg, { x: -453, y: -624 }));
+      dragging.end();
+
+      expect(subProcess.width).toEqual(140);
+      expect(subProcess.height).toEqual(120);
+    }));
+
+
+    it('should snap a Participant to minimum bounds', inject(function(canvas, elementRegistry, resize, dragging) {
+
+      var participant = elementRegistry.get('Participant_1');
+
+      resize.activate(Events.create(canvas._svg, { x: 614, y: 310 }), participant, 'se');
+      dragging.move(Events.create(canvas._svg, { x: -614, y: -310 }));
+      dragging.end();
+
+      expect(participant.width).toEqual(400);
+      expect(participant.height).toEqual(200);
+    }));
+
+    it('should snap a TextAnnotation to minimum bounds', inject(function(canvas, elementRegistry, resize, dragging) {
+      
+      var textAnnotation = elementRegistry.get('TextAnnotation_1');
+
+      resize.activate(Events.create(canvas._svg, { x: 592, y: 452 }), textAnnotation, 'se');
+      dragging.move(Events.create(canvas._svg, { x: -592, y: -452 }));
+      dragging.end();
+
+      expect(textAnnotation.width).toEqual(50);
+      expect(textAnnotation.height).toEqual(50);
+    }));
+
+  });
+
 });