Remove external dependency from SimulationViewMainComponent

Previously, panelTop had to be defined externally whenever
SimulationViewMainComponent was used. I renamed it and set a default
so the binding by a parent is optional.

CURA-6853

plugins/PreviewStage/PreviewMain.qml

@@ -13,11 +13,18 @@ Item
 {
     Loader
     {
-        property var panelTop: actionPanelWidget.y
         id: previewMain
         anchors.fill: parent
 
         source: UM.Controller.activeView != null && UM.Controller.activeView.mainComponent != null ? UM.Controller.activeView.mainComponent : ""
+
+        // Indicate that the layer slider should stay above the action panel
+        Binding
+        {
+            target: previewMain.item
+            property: "layerSliderSafeYMax"
+            value: actionPanelWidget.y
+        }
     }
 
     Cura.ActionPanelWidget

plugins/SimulationView/LayerSlider.qml

@@ -338,7 +338,6 @@ Item
         // set the slider position based on the lower value
         function setValue(value)
         {
-            print("lower handle set value: " + value)
             // Normalize values between range, since using arrow keys will create out-of-the-range values
             value = sliderRoot.normalizeValue(value)
 

plugins/SimulationView/SimulationViewMainComponent.qml

@@ -12,6 +12,11 @@ import Cura 1.0 as Cura
 Item
 {
     property bool is_simulation_playing: false
+    // By default, the layer slider can extend to the entire height of the parent
+    // A parent may bind this property to indicate the bottom of a safe area
+    // for the Layer slider
+    property var layerSliderSafeYMax: parent.height
+
     visible: UM.SimulationView.layerActivity && CuraApplication.platformActivity
 
     // A slider which lets users trace a single layer (XY movements)
@@ -179,13 +184,13 @@ Item
         id: layerSlider
 
         width: UM.Theme.getSize("slider_handle").width
-        height: preferredHeight + heightMargin * 2 < panelTop ? preferredHeight : panelTop - heightMargin * 2
+        height: preferredHeight + heightMargin * 2 < layerSliderSafeYMax ? preferredHeight : layerSliderSafeYMax - heightMargin * 2
 
         anchors
         {
             right: parent.right
             verticalCenter: parent.verticalCenter
-            verticalCenterOffset: -(parent.height - panelTop) / 2 // center between parent top and panelTop
+            verticalCenterOffset: -(parent.height - layerSliderSafeYMax) / 2 // center between parent top and layerSliderSafeYMax
             rightMargin: UM.Theme.getSize("default_margin").width
             bottomMargin: heightMargin
             topMargin: heightMargin
@@ -216,7 +221,6 @@ Item
         // Make sure the slider handlers show the correct value after switching views
         Component.onCompleted:
         {
-            print("paneltop", panelTop, "screenscaleFactor")
             layerSlider.setLowerValue(UM.SimulationView.minimumLayer)
             layerSlider.setUpperValue(UM.SimulationView.currentLayer)
         }