Add a Job subclass that handles sending data to the engine

This can be used by the CuraEngine backend to reduce lag when we start
slicing.

Contributes to CURA-358

plugins/CuraEngineBackend/StartSliceJob.py

@@ -0,0 +1,123 @@
+# Copyright (c) 2015 Ultimaker B.V.
+# Cura is released under the terms of the AGPLv3 or higher.
+
+import time
+import numpy
+
+from UM.Job import Job
+from UM.Application import Application
+from UM.Logger import Logger
+
+from UM.Scene.SceneNode import SceneNode
+from UM.Scene.Iterator.DepthFirstIterator import DepthFirstIterator
+
+from cura.OneAtATimeIterator import OneAtATimeIterator
+
+from . import Cura_pb2
+
+class StartSliceJob(Job):
+    def __init__(self, profile, socket):
+        super().__init__()
+
+        self._scene = Application.getInstance().getController().getScene()
+        self._profile = profile
+        self._socket = socket
+
+    def run(self):
+        self._scene.acquireLock()
+
+        for node in DepthFirstIterator(self._scene.getRoot()):
+            if node.callDecoration("getLayerData"):
+                node.getParent().removeChild(node)
+                break
+
+        object_groups = []
+        if self._profile.getSettingValue("print_sequence") == "one_at_a_time":
+            for node in OneAtATimeIterator(self._scene.getRoot()):
+                temp_list = []
+
+                if getattr(node, "_outside_buildarea", False):
+                    continue
+
+                children = node.getAllChildren()
+                children.append(node)
+                for child_node in children:
+                    if type(child_node) is SceneNode and child_node.getMeshData() and child_node.getMeshData().getVertices() is not None:
+                        temp_list.append(child_node)
+
+                object_groups.append(temp_list)
+                Job.yieldThread()
+        else:
+            temp_list = []
+            for node in DepthFirstIterator(self._scene.getRoot()):
+                if type(node) is SceneNode and node.getMeshData() and node.getMeshData().getVertices() is not None:
+                    if not getattr(node, "_outside_buildarea", False):
+                        temp_list.append(node)
+                Job.yieldThread()
+            object_groups.append(temp_list)
+
+        self._scene.releaseLock()
+
+        if not object_groups:
+            return
+
+        self._sendSettings(self._profile)
+
+        slice_message = Cura_pb2.Slice()
+
+        for group in object_groups:
+            group_message = slice_message.object_lists.add()
+            for object in group:
+                print(object)
+                mesh_data = object.getMeshData().getTransformed(object.getWorldTransformation())
+
+                obj = group_message.objects.add()
+                obj.id = id(object)
+
+                verts = numpy.array(mesh_data.getVertices())
+                verts[:,[1,2]] = verts[:,[2,1]]
+                verts[:,1] *= -1
+                obj.vertices = verts.tostring()
+
+                self._handlePerObjectSettings(object, obj)
+
+                Job.yieldThread()
+
+            # Hack to add per-object settings also to the "MeshGroup" in CuraEngine
+            # We really should come up with a better solution for this.
+            self._handlePerObjectSettings(group[0], group_message)
+
+        Logger.log("d", "Sending data to engine for slicing.")
+        self._socket.sendMessage(slice_message)
+
+        self.setResult(True)
+
+    def _sendSettings(self, profile):
+        msg = Cura_pb2.SettingList()
+        for key, value in profile.getAllSettingValues(include_machine = True).items():
+            s = msg.settings.add()
+            s.name = key
+            s.value = str(value).encode("utf-8")
+
+        self._socket.sendMessage(msg)
+
+    def _handlePerObjectSettings(self, node, message):
+        profile = node.callDecoration("getProfile")
+        if profile:
+            for key, value in profile.getChangedSettingValues().items():
+                setting = message.settings.add()
+                setting.name = key
+                setting.value = str(value).encode()
+
+                Job.yieldThread()
+
+        object_settings = node.callDecoration("getAllSettingValues")
+        if not object_settings:
+            return
+
+        for key, value in object_settings.items():
+            setting = message.settings.add()
+            setting.name = key
+            setting.value = str(value).encode()
+
+            Job.yieldThread()