Added start & stop camera interface

CURA-2411

cura/PrinterOutputDevice.py

@@ -134,6 +134,20 @@ class PrinterOutputDevice(QObject, OutputDevice):
     def _setJobState(self, job_state):
         Logger.log("w", "_setJobState is not implemented by this output device")
 
+    @pyqtSlot()
+    def startCamera(self):
+        self._startCamera()
+
+    def _startCamera(self, job_state):
+        Logger.log("w", "_startCamera is not implemented by this output device")
+
+    @pyqtSlot()
+    def stopCamera(self):
+        self._stopCamera()
+
+    def _stopCamera(self, job_state):
+        Logger.log("w", "_stopCamera is not implemented by this output device")
+
     @pyqtProperty(str, notify = jobNameChanged)
     def jobName(self):
         return self._job_name

resources/qml/Cura.qml

@@ -402,6 +402,16 @@ UM.MainWindow
                 anchors.verticalCenter: parent.verticalCenter
                 anchors.horizontalCenterOffset: - UM.Theme.getSize("sidebar").width / 2
                 visible: base.monitoringPrint
+                onVisibleChanged:
+                {
+                    if(visible)
+                    {
+                        Cura.MachineManager.printerOutputDevices[0].startCamera()
+                    } else
+                    {
+                        Cura.MachineManager.printerOutputDevices[0].stopCamera()
+                    }
+                }
                 source:
                 {
                     if(!base.monitoringPrint)