Rescale the current layer number based on the maximum layer

This makes sure we still have the top layer selected when we
receive new data.

Contributes to Asana issue 34806173176751

plugins/LayerView/LayerView.py

@@ -18,10 +18,10 @@ class LayerView(View):
         self._material = None
         self._num_layers = 0
         self._layer_percentage = 0 # what percentage of layers need to be shown (SLider gives value between 0 - 100)
-        self._current_layer_num = 0
         self._proxy = LayerViewProxy.LayerViewProxy()
         self._controller.getScene().sceneChanged.connect(self._onSceneChanged)
         self._max_layers = 10
+        self._current_layer_num = 10
 
     def getCurrentLayer(self):
         return self._current_layer_num
@@ -87,7 +87,7 @@ class LayerView(View):
             renderer.setRenderSelection(False)
             self._old_max_layers = self._max_layers
             ## Recalculate num max layers
-            self._max_layers = 0
+            new_max_layers = 0
             for node in DepthFirstIterator(scene.getRoot()):
                 if not node.render(renderer):
                     if node.getMeshData() and node.isVisible():
@@ -95,11 +95,15 @@ class LayerView(View):
                             layer_data = node.getMeshData().layerData
                         except AttributeError:
                             continue
-                        if self._max_layers < len(layer_data.getLayers()):
-                            self._max_layers = len(layer_data.getLayers())
-            
-            if self._max_layers != self._old_max_layers:
+                        if new_max_layers < len(layer_data.getLayers()):
+                            new_max_layers = len(layer_data.getLayers())
+
+            if new_max_layers > 0 and new_max_layers != self._old_max_layers:
+                self._max_layers = new_max_layers
                 self.maxLayersChanged.emit()
+
+                # This makes sure we update the current layer
+                self.setLayer(int(self._max_layers * (self._current_layer_num / self._old_max_layers)))
     
     maxLayersChanged = Signal()
     

plugins/LayerView/LayerView.qml

@@ -21,6 +21,7 @@ Item
         orientation: Qt.Vertical
         minimumValue: 0;
         maximumValue: UM.LayerView.numLayers;
+        stepSize: 1
 
         value: UM.LayerView.currentLayer
         onValueChanged: UM.LayerView.setCurrentLayer(value)