Hello Slicer Community,
I am currently developing an extension for high-resolution screen captures within Slicer. My goal is to programmatically capture images of a reconstructed scene that include markup annotations such as landmark names, angles, and distance measurements. However, I’ve encountered an issue where these markup labels do not appear in the off-screen rendering used for capturing the scene. My research points to the existence of a vtkMRMLDisplayableManagerGroup object that should be associated with my threeDView. This group should contain the displayable managers responsible for rendering the markup labels. How would I go about accessing this object so I can incorporate these markup annotations into the newly rendered scene?
Below is the core snippet of my screen capture logic:
def runScreenCapture(self) -> None:
if self.resolution and self.outputPath:
vtk.vtkGraphicsFactory()
gf = vtk.vtkGraphicsFactory()
gf.SetOffScreenOnlyMode(1)
gf.SetUseMesaClasses(1)
rw = vtk.vtkRenderWindow()
rw.SetOffScreenRendering(1)
ren = vtk.vtkRenderer()
rw.SetSize(self.resolution[0], self.resolution[1])
lm = slicer.app.layoutManager()
threeDViewWidget = lm.threeDWidget(self.threeDViewIndex)
threeDView = threeDViewWidget.threeDView()
renderers = threeDView.renderWindow().GetRenderers()
ren3d = renderers.GetFirstRenderer()
# Set the background color of the off-screen renderer to match the original
backgroundColor = ren3d.GetBackground()
ren.SetBackground(backgroundColor)
camera = ren3d.GetActiveCamera()
while ren3d:
actors = ren3d.GetActors()
for index in range(actors.GetNumberOfItems()):
actor = actors.GetItemAsObject(index)
actor_class_name = actor.GetClassName() # Get the class name using VTK's method
# Alternatively, use Python's type function: actor_type = type(actor).__name__
print("Actor index:", index, "Class name:", actor_class_name)
property = actor.GetProperty()
# print("Actor Property:", property)
representation = property.GetRepresentation()
# vtkProperty defines three representation types:
# vtkProperty.VTK_POINTS, vtkProperty.VTK_WIREFRAME, vtkProperty.VTK_SURFACE
if representation == vtk.VTK_POINTS:
print("Actor index:", index, "is represented as points.")
elif representation == vtk.VTK_WIREFRAME:
print("Actor index:", index, "is represented as wireframe.")
elif representation == vtk.VTK_SURFACE:
print("Actor index:", index, "is represented as a surface.")
else:
print("Actor index:", index, "has an unknown representation.")
print("Actor index:", index, "Visibility -", actor.GetVisibility(), "|", isActorVisible(camera, actor))
if actor.GetVisibility(): # and isActorVisible(camera, actor):
ren.AddActor(actor) # Add only visible actors
lights = ren3d.GetLights()
for index in range(lights.GetNumberOfItems()):
ren.AddLight(lights.GetItemAsObject(index))
volumes = ren3d.GetVolumes()
for index in range(volumes.GetNumberOfItems()):
ren.AddVolume(volumes.GetItemAsObject(index))
ren3d = renderers.GetNextItem()
ren.SetActiveCamera(camera)
rw.AddRenderer(ren)
rw.Render()
wti = vtk.vtkWindowToImageFilter()
wti.SetInput(rw)
wti.Update()
writer = vtk.vtkPNGWriter()
writer.SetInputConnection(wti.GetOutputPort())
writer.SetFileName(self.outputPath)
writer.Update()
writer.Write()
i = wti.GetOutput()
