From 62d7746e81e8b61eff31b20daeb516834f07afd8 Mon Sep 17 00:00:00 2001
From: Philipp Fromme <philippfromme@outlook.com>
Date: Fri, 10 May 2019 11:28:15 +0200
Subject: [PATCH] feat(bpmn-snapping): snap shape to itself

Closes #993
---
 lib/features/snapping/BpmnSnapping.js         |  8 +++-
 .../snapping/BpmnSnapping.general.bpmn        | 38 +++++++++++++++
 .../features/snapping/BpmnSnappingSpec.js     | 46 +++++++++++++++++++
 3 files changed, 91 insertions(+), 1 deletion(-)
 create mode 100644 test/spec/features/snapping/BpmnSnapping.general.bpmn

diff --git a/lib/features/snapping/BpmnSnapping.js b/lib/features/snapping/BpmnSnapping.js
index 14c1e1a6..4920678d 100644
--- a/lib/features/snapping/BpmnSnapping.js
+++ b/lib/features/snapping/BpmnSnapping.js
@@ -1,7 +1,8 @@
 import inherits from 'inherits';
 
 import {
-  forEach
+  forEach,
+  isNumber
 } from 'min-dash';
 
 import {
@@ -316,6 +317,11 @@ BpmnSnapping.prototype.initSnap = function(event) {
 
 BpmnSnapping.prototype.addTargetSnaps = function(snapPoints, shape, target) {
 
+  // snap shape to itself
+  if (isNumber(shape.x) && isNumber(shape.y)) {
+    snapPoints.add('mid', mid(shape));
+  }
+
   // use target parent as snap target
   if (is(shape, 'bpmn:BoundaryEvent') && shape.type !== 'label') {
     target = target.parent;
diff --git a/test/spec/features/snapping/BpmnSnapping.general.bpmn b/test/spec/features/snapping/BpmnSnapping.general.bpmn
new file mode 100644
index 00000000..0f48812e
--- /dev/null
+++ b/test/spec/features/snapping/BpmnSnapping.general.bpmn
@@ -0,0 +1,38 @@
+<?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:dc="http://www.omg.org/spec/DD/20100524/DC" xmlns:di="http://www.omg.org/spec/DD/20100524/DI" id="Definitions_1" targetNamespace="http://bpmn.io/schema/bpmn" exporter="Camunda Modeler" exporterVersion="3.1.0">
+  <bpmn:process id="Process_1" isExecutable="true">
+    <bpmn:startEvent id="StartEvent_1">
+      <bpmn:outgoing>SequenceFlow_1</bpmn:outgoing>
+    </bpmn:startEvent>
+    <bpmn:task id="Task_1">
+      <bpmn:incoming>SequenceFlow_1</bpmn:incoming>
+      <bpmn:outgoing>SequenceFlow_2</bpmn:outgoing>
+    </bpmn:task>
+    <bpmn:sequenceFlow id="SequenceFlow_1" sourceRef="StartEvent_1" targetRef="Task_1" />
+    <bpmn:endEvent id="EndEvent_1">
+      <bpmn:incoming>SequenceFlow_2</bpmn:incoming>
+    </bpmn:endEvent>
+    <bpmn:sequenceFlow id="SequenceFlow_2" sourceRef="Task_1" targetRef="EndEvent_1" />
+  </bpmn:process>
+  <bpmndi:BPMNDiagram id="BPMNDiagram_1">
+    <bpmndi:BPMNPlane id="BPMNPlane_1" bpmnElement="Process_1">
+      <bpmndi:BPMNShape id="_BPMNShape_StartEvent_2" bpmnElement="StartEvent_1">
+        <dc:Bounds x="156" y="103" width="36" height="36" />
+      </bpmndi:BPMNShape>
+      <bpmndi:BPMNShape id="Task_1_di" bpmnElement="Task_1">
+        <dc:Bounds x="242" y="81" width="100" height="80" />
+      </bpmndi:BPMNShape>
+      <bpmndi:BPMNEdge id="SequenceFlow_1_di" bpmnElement="SequenceFlow_1">
+        <di:waypoint x="192" y="121" />
+        <di:waypoint x="242" y="121" />
+      </bpmndi:BPMNEdge>
+      <bpmndi:BPMNShape id="EndEvent_1_di" bpmnElement="EndEvent_1">
+        <dc:Bounds x="392" y="103" width="36" height="36" />
+      </bpmndi:BPMNShape>
+      <bpmndi:BPMNEdge id="SequenceFlow_2_di" bpmnElement="SequenceFlow_2">
+        <di:waypoint x="342" y="121" />
+        <di:waypoint x="392" y="121" />
+      </bpmndi:BPMNEdge>
+    </bpmndi:BPMNPlane>
+  </bpmndi:BPMNDiagram>
+</bpmn:definitions>
diff --git a/test/spec/features/snapping/BpmnSnappingSpec.js b/test/spec/features/snapping/BpmnSnappingSpec.js
index 14fab963..1fd79ca4 100644
--- a/test/spec/features/snapping/BpmnSnappingSpec.js
+++ b/test/spec/features/snapping/BpmnSnappingSpec.js
@@ -29,6 +29,52 @@ describe('features/snapping - BpmnSnapping', function() {
     connectModule
   ];
 
+  describe('general', function() {
+
+    var diagramXML = require('./BpmnSnapping.general.bpmn');
+
+    beforeEach(bootstrapModeler(diagramXML, {
+      modules: testModules
+    }));
+
+    var task;
+
+    beforeEach(inject(function(dragging, elementRegistry) {
+      task = elementRegistry.get('Task_1');
+
+      dragging.setOptions({ manual: true });
+    }));
+
+
+    it('should snap to itself', inject(function(canvas, dragging, move) {
+
+      // given
+      var originalPosition = {
+        x: task.x,
+        y: task.y
+      };
+
+      var taskGfx = canvas.getGraphics(task);
+
+      // when
+      move.start(canvasEvent(originalPosition), task);
+
+      dragging.hover({ element: task, gfx: taskGfx });
+
+      dragging.move(canvasEvent({
+        x: originalPosition.x + 5,
+        y: originalPosition.y + 5
+      }));
+
+      dragging.end();
+
+      // then
+      expect(task.x).to.eql(originalPosition.x);
+      expect(task.y).to.eql(originalPosition.y);
+    }));
+
+  });
+
   describe('on Boundary Events', function() {
 
     var diagramXML = require('../../../fixtures/bpmn/collaboration/process.bpmn');