Issue #222: Tidy VTKOverlayWindow and fix unit tests.

sksurgeryvtk/widgets/vtk_overlay_window.py

@@ -515,26 +515,9 @@ def add_vtk_models(self, models, layer=1):
         that is a vtkActor.
 
         :param models: list of VTK models.
-        :param layer:  Render layer to add to, default 1 (forground)
+        :param layer:  [1|3|4]. Render layer to add to, default 1.
         """
-
-        if layer == 0:
-            raise ValueError("You shouldn't add actors to the background video.")
-
-        if layer == 1:
-            renderer = self.layer_1_renderer
-
-        elif layer == 2:
-            raise ValueError("You shouldn't add actors to the midground video.")
-
-        elif layer == 3:
-            renderer = self.layer_3_renderer
-
-        elif layer == 4:
-            renderer = self.layer_4_renderer
-
-        else:
-            raise ValueError("Invalid layer specified")
+        renderer = self.get_foreground_renderer(layer=layer)
 
         for model in models:
             renderer.AddActor(model.actor)
@@ -549,26 +532,9 @@ def add_vtk_actor(self, actor, layer=1):
         Add a vtkActor directly.
 
         :param actor: vtkActor
-        :param layer: Render layer to add to, default 1 (foreground)
+        :param layer: [1|3|4]. Render layer to add to, default 1.
         """
-
-        if layer == 0:
-            raise ValueError("You shouldn't add actors to the background video.")
-
-        if layer == 1:
-            renderer = self.layer_1_renderer
-
-        elif layer == 2:
-            raise ValueError("You shouldn't add actors to the midground video.")
-
-        elif layer == 3:
-            renderer = self.layer_3_renderer
-
-        elif layer == 4:
-            renderer = self.layer_4_renderer
-
-        else:
-            raise ValueError("Invalid layer specified")
+        renderer = self.get_foreground_renderer(layer=layer)
 
         renderer.AddActor(actor)
 
@@ -577,26 +543,28 @@ def add_vtk_actor(self, actor, layer=1):
 
     def get_background_image_actor(self, layer=0):
         """
-        Returns one of the background video layers, depending on
-        the constructor arguments. So, either layer 0 or 2.
+        Returns one of the background video image actors.
+
+        :param layer: [0|2]. Index of image actor. Default 0.
         """
         if layer == 0:
             return self.layer_0_image_actor
         if layer == 1:
-            raise ValueError("Layer 1 is not a background renderer.")
+            raise ValueError("Layer 1 is not a background actor.")
         if layer == 2:
             return self.layer_2_image_actor
         if layer == 3:
-            raise ValueError("Layer 3 is not a background renderer.")
+            raise ValueError("Layer 3 is not a background actor.")
         if layer == 4:
-            raise ValueError("Layer 3 is not a background renderer.")
+            raise ValueError("Layer 4 is not a background actor.")
 
-        raise ValueError("Didn't find background renderer.")
+        raise ValueError("Didn't find background actor.")
 
     def get_background_renderer(self, layer=0):
         """
-        Returns one of the background video layers, depending on
-        the constructor arguments. So, either layer 0 or 2.
+        Returns one of the background video layers.
+
+        :param layer: [0|2]. Index of background image renderer. Default 0.
         """
         if layer == 0:
             return self.layer_0_renderer
@@ -607,7 +575,7 @@ def get_background_renderer(self, layer=0):
         if layer == 3:
             raise ValueError("Layer 3 is not a background renderer.")
         if layer == 4:
-            raise ValueError("Layer 3 is not a background renderer.")
+            raise ValueError("Layer 4 is not a background renderer.")
 
         raise ValueError("Didn't find background renderer.")
 
@@ -627,7 +595,7 @@ def get_foreground_renderer(self, layer=1):
         if layer == 3:
             return self.layer_3_renderer
         if layer == 4:
-            raise ValueError("Layer 4 is only for annotations like text.")
+            return self.layer_4_renderer
 
         raise ValueError(f"Invalid layer specification:{layer}")
 

tests/widgets/test_vtk_overlay_window_5_layers.py

@@ -114,7 +114,7 @@ def test_overlay_window_video_2(setup_vtk_overlay_window_video_only_layer_2):
     vtk_overlay.show()
     vtk_overlay.Render()
 
-    bg_ren = vtk_overlay.get_background_renderer()
+    bg_ren = vtk_overlay.get_background_renderer(layer=2)
     assert bg_ren == vtk_overlay.layer_2_renderer
 
     fg_ren = vtk_overlay.get_foreground_renderer()
@@ -180,15 +180,15 @@ def test_overlay_window_video_both(setup_vtk_overlay_window_video_both_layer_0_a
     fg_ren = vtk_overlay.get_foreground_renderer(layer=3)
     assert fg_ren == vtk_overlay.layer_3_renderer
 
+    fg_ren = vtk_overlay.get_foreground_renderer(layer=4)
+    assert fg_ren == vtk_overlay.layer_4_renderer
+
     with pytest.raises(ValueError):
         fg_ren = vtk_overlay.get_foreground_renderer(layer=0)
 
     with pytest.raises(ValueError):
         fg_ren = vtk_overlay.get_foreground_renderer(layer=2)
 
-    with pytest.raises(ValueError):
-        fg_ren = vtk_overlay.get_foreground_renderer(layer=4)
-
     with pytest.raises(ValueError):
         fg_ren = vtk_overlay.get_foreground_renderer(layer=5)
 
@@ -223,7 +223,7 @@ def test_overlay_window_combined_ar_look(setup_vtk_overlay_window_video_only_lay
     vtk_overlay.show()
     vtk_overlay.Render()
 
-    bg_ren = vtk_overlay.get_background_renderer()
+    bg_ren = vtk_overlay.get_background_renderer(layer=2)
     assert bg_ren == vtk_overlay.layer_2_renderer
 
     fg_ren = vtk_overlay.get_foreground_renderer(layer=1)