CURA-4425 first thumbnail in UFP file; updated CuraSceneModel and PreviewPass

cura/Snapshot.py

@@ -0,0 +1,74 @@
+# Copyright (c) 2018 Ultimaker B.V.
+# Cura is released under the terms of the LGPLv3 or higher.
+from PyQt5 import QtCore
+
+from cura.PreviewPass import PreviewPass
+
+from UM.Application import Application
+from UM.Math.AxisAlignedBox import AxisAlignedBox
+from UM.Math.Matrix import Matrix
+from UM.Math.Vector import Vector
+from UM.Scene.Camera import Camera
+from UM.Scene.Iterator.DepthFirstIterator import DepthFirstIterator
+
+
+class Snapshot:
+    @staticmethod
+    def snapshot(width = 300, height = 300):
+        scene = Application.getInstance().getController().getScene()
+        cam = scene.getActiveCamera()
+        render_width, render_height = cam.getWindowSize()
+        pp = PreviewPass(render_width, render_height)
+
+        root = scene.getRoot()
+        camera = Camera("snapshot", root)
+
+        # determine zoom and look at
+        bbox = None
+        for node in DepthFirstIterator(root):
+            if node.callDecoration("isSliceable") and node.getMeshData() and node.isVisible():
+                if bbox is None:
+                    bbox = node.getBoundingBox()
+                else:
+                    bbox += node.getBoundingBox()
+        if bbox is None:
+            bbox = AxisAlignedBox()
+        look_at = bbox.center
+        size = max(bbox.width, bbox.height, bbox.depth * 0.5)
+
+        looking_from_offset = Vector(1, 1, 2)
+        if size > 0:
+            # determine the watch distance depending on the size
+            looking_from_offset = looking_from_offset * size * 1.3
+        camera.setViewportSize(render_width, render_height)
+        camera.setWindowSize(render_width, render_height)
+        camera.setPosition(look_at + looking_from_offset)
+        camera.lookAt(look_at)
+
+        # Somehow the aspect ratio is also influenced in reverse by the screen width/height
+        # So you have to set it to render_width/render_height to get 1
+        projection_matrix = Matrix()
+        projection_matrix.setPerspective(30, render_width / render_height, 1, 500)
+
+        camera.setProjectionMatrix(projection_matrix)
+
+        pp.setCamera(camera)
+        pp.setSize(render_width, render_height)  # texture size
+        pp.render()
+        pixel_output = pp.getOutput()
+
+        # It's a bit annoying that window size has to be taken into account
+        if pixel_output.width() >= pixel_output.height():
+            # Scale it to the correct height
+            image = pixel_output.scaledToHeight(height, QtCore.Qt.SmoothTransformation)
+            # Then chop of the width
+            cropped_image = image.copy(image.width() // 2 - width // 2, 0, width, height)
+        else:
+            # Scale it to the correct width
+            image = pixel_output.scaledToWidth(width, QtCore.Qt.SmoothTransformation)
+            # Then chop of the height
+            cropped_image = image.copy(0, image.height() // 2 - height // 2, width, height)
+
+        return cropped_image
+        # if cropped_image.save("/home/jack/preview.png"):
+        #     print("yooo")