VTK-based show_object

cadquery/vis.py

@@ -0,0 +1,97 @@
+from . import Shape, Workplane, Assembly, Sketch, Compound, Color
+from .occ_impl.exporters.assembly import _vtkRenderWindow
+from .occ_impl.jupyter_tools import DEFAULT_COLOR
+
+from typing import Union
+
+from OCP.TopoDS import TopoDS_Shape
+
+from vtkmodules.vtkInteractionWidgets import vtkOrientationMarkerWidget
+from vtkmodules.vtkRenderingAnnotation import vtkAxesActor
+from vtkmodules.vtkInteractionStyle import vtkInteractorStyleTrackballCamera
+from vtkmodules.vtkRenderingCore import vtkMapper, vtkRenderWindowInteractor
+
+
+def _to_assy(*objs: Union[Shape, Workplane, Assembly, Sketch]) -> Assembly:
+
+    assy = Assembly(color=Color(*DEFAULT_COLOR))
+
+    for obj in objs:
+        if isinstance(obj, (Shape, Workplane, Assembly)):
+            assy.add(obj)
+        elif isinstance(obj, Sketch):
+            assy.add(obj._faces)
+            assy.add(Compound.makeCompound(obj._edges))
+            assy.add(Compound.makeCompound(obj._wires))
+        elif isinstance(obj, TopoDS_Shape):
+            assy.add(Shape(obj))
+        else:
+            raise ValueError(f"{obj} has unsupported type {type(obj)}")
+
+    return assy
+
+
+def show(*objs: Union[Shape, Workplane, Assembly, Sketch]):
+    """
+    Show CQ objects using VTK
+    """
+
+    # construct the assy
+    assy = _to_assy(*objs)
+
+    # create a VTK window
+    win = _vtkRenderWindow(assy)
+
+    win.SetWindowName("CQ viewer")
+
+    # rendering related settings
+    win.SetMultiSamples(16)
+    vtkMapper.SetResolveCoincidentTopologyToPolygonOffset()
+    vtkMapper.SetResolveCoincidentTopologyPolygonOffsetParameters(1, 0)
+    vtkMapper.SetResolveCoincidentTopologyLineOffsetParameters(-1, 0)
+
+    # create a VTK interactor
+    inter = vtkRenderWindowInteractor()
+    inter.SetInteractorStyle(vtkInteractorStyleTrackballCamera())
+    inter.SetRenderWindow(win)
+
+    # construct an axes indicator
+    axes = vtkAxesActor()
+    axes.SetDragable(0)
+
+    tp = axes.GetXAxisCaptionActor2D().GetCaptionTextProperty()
+    tp.SetColor(0, 0, 0)
+
+    axes.GetYAxisCaptionActor2D().GetCaptionTextProperty().ShallowCopy(tp)
+    axes.GetZAxisCaptionActor2D().GetCaptionTextProperty().ShallowCopy(tp)
+
+    # add to an orientation widget
+    orient_widget = vtkOrientationMarkerWidget()
+    orient_widget.SetOrientationMarker(axes)
+    orient_widget.SetViewport(0.9, 0.0, 1.0, 0.2)
+    orient_widget.SetZoom(1.1)
+    orient_widget.SetInteractor(inter)
+    orient_widget.EnabledOn()
+    orient_widget.InteractiveOff()
+
+    # use gradient background
+    renderer = win.GetRenderers().GetFirstRenderer()
+    renderer.GradientBackgroundOn()
+
+    # set size and camera
+    win.SetSize(*win.GetScreenSize())
+    win.SetPosition(-10, 0)
+
+    camera = renderer.GetActiveCamera()
+    camera.Roll(-35)
+    camera.Elevation(-45)
+    renderer.ResetCamera()
+
+    # show and return
+    inter.Initialize()
+    win.Render()
+    inter.Start()
+
+
+# alias
+show_object = show

tests/test_vis.py

@@ -0,0 +1,83 @@
+from cadquery import Workplane, Assembly, Sketch
+from cadquery.vis import show, show_object
+
+import cadquery.occ_impl.exporters.assembly as assembly
+import cadquery.vis as vis
+
+from vtkmodules.vtkRenderingCore import vtkRenderWindow, vtkRenderWindowInteractor
+
+from pytest import fixture, raises
+
+
+@fixture
+def wp():
+
+    return Workplane().box(1, 1, 1)
+
+
+@fixture
+def assy(wp):
+
+    return Assembly().add(wp)
+
+
+@fixture
+def sk():
+
+    return Sketch().circle(1.0)
+
+
+class FakeInteractor(vtkRenderWindowInteractor):
+    def Start(self):
+
+        pass
+
+    def Initialize(self):
+
+        pass
+
+
+class FakeWindow(vtkRenderWindow):
+    def Render(*args):
+
+        pass
+
+    def SetSize(*args):
+
+        pass
+
+    def GetScreenSize(*args):
+
+        return 1, 1
+
+    def SetPosition(*args):
+
+        pass
+
+
+def test_show(wp, assy, sk, monkeypatch):
+
+    # use some dummy vtk objects
+    monkeypatch.setattr(vis, "vtkRenderWindowInteractor", FakeInteractor)
+    monkeypatch.setattr(assembly, "vtkRenderWindow", FakeWindow)
+
+    # simple smoke test
+    show(wp)
+    show(wp.val())
+    show(assy)
+    show(sk)
+    show(wp, sk, assy, wp.val())
+    show()
+
+    with raises(ValueError):
+        show(1)
+
+    show_object(wp)
+    show_object(wp.val())
+    show_object(assy)
+    show_object(sk)
+    show_object(wp, sk, assy, wp.val())
+    show_object()
+
+    with raises(ValueError):
+        show_object("a")