Fitt's Law improvements for applets

--each applets layout can not identify properly
which applet is the first/last visible from its
contents. This way we can now identify properly
at all cases which applets should remove their
margins in order to follow Fitt's Law at screen
edges. For example when a windows buttons applet
is found at the screen edge and suddently it
hides itself then the next visible applet should
be considered at screen edge and such should remove
its margins in order to touch the screen edge.

containment/package/contents/ui/applet/AppletItem.qml

@@ -84,8 +84,8 @@ Item {
     property bool isSpacer: applet && (applet.pluginName === "org.kde.latte.spacer")
     property bool isSystray: applet && (applet.pluginName === "org.kde.plasma.systemtray" || applet.pluginName === "org.nomad.systemtray" )
 
-    property bool firstChildOfStartLayout: (index === layoutsContainer.startLayout.beginIndex)
-    property bool lastChildOfEndLayout: ((index === layoutsContainer.endLayout.beginIndex+layoutsContainer.endLayout.count-1)&&(layoutsContainer.endLayout.count>1))
+    property bool firstChildOfStartLayout: index === layoutsContainer.startLayout.firstVisibleIndex
+    property bool lastChildOfEndLayout: index === layoutsContainer.endLayout.lastVisibleIndex
 
     readonly property bool atScreenEdge: {
         if (root.isHorizontal) {
@@ -106,14 +106,15 @@ Item {
     }
 
     //applet is in starting edge
-    /*property bool startEdge: index < layoutsContainer.endLayout.beginIndex ? (index === 0)&&(layoutsContainer.mainLayout.count > 1) :
-                                                               (index === layoutsContainer.endLayout.beginIndex)&&(layoutsContainer.endLayout.count > 1)*/
-    property bool startEdge: (index === layoutsContainer.startLayout.beginIndex) || (index === layoutsContainer.mainLayout.beginIndex) || (index === layoutsContainer.endLayout.beginIndex)
+    property bool startEdge: (index >=0) &&
+                             ((index === layoutsContainer.startLayout.firstVisibleIndex)
+                              || (index === layoutsContainer.mainLayout.firstVisibleIndex)
+                              || (index === layoutsContainer.endLayout.firstVisibleIndex))
     //applet is in ending edge
-    property bool endEdge: plasmoid.configuration.panelPosition !== Latte.Types.Justify ? (index === layoutsContainer.mainLayout.beginIndex + layoutsContainer.mainLayout.count - 1)&&(layoutsContainer.mainLayout.count>1) :
-                                                                                          (((index === layoutsContainer.startLayout.beginIndex+layoutsContainer.startLayout.count-2)&&(layoutsContainer.startLayout.count>2))
-                                                                                           ||((index === layoutsContainer.mainLayout.beginIndex+layoutsContainer.mainLayout.count-2)&&(layoutsContainer.mainLayout.count>2))
-                                                                                           ||((index === layoutsContainer.endLayout.beginIndex+layoutsContainer.endLayout.count-1)&&(layoutsContainer.endLayout.count>1)))
+    property bool endEdge: (index >=0) &&
+                           ((index === layoutsContainer.startLayout.lastVisibleIndex)
+                            || (index === layoutsContainer.mainLayout.lastVisibleIndex)
+                            || (index === layoutsContainer.endLayout.lastVisibleIndex))
 
     readonly property bool acceptMouseEvents: applet && !isLattePlasmoid && !originalAppletBehavior && !appletItem.isSeparator && !communicator.parabolicEffectLocked
     readonly property bool originalAppletBehavior: (root.zoomFactor === 1 && !lockZoom /*hacky flag to keep Latte behavior*/)
@@ -466,8 +467,8 @@ Item {
 
     Component.onDestruction: {
         if (animationWasSent) {
-             root.slotAnimationsNeedBothAxis(-1);
-             animationWasSent = false;
+            root.slotAnimationsNeedBothAxis(-1);
+            animationWasSent = false;
         }
 
         if (isSeparator){

containment/package/contents/ui/layouts/AppletsContainer.qml

@@ -91,6 +91,57 @@ Grid {
         return no;
     }
 
+    property int firstVisibleIndex: -1
+    property int lastVisibleIndex: -1
+
+    Binding{
+        target: appletsContainer
+        property:"firstVisibleIndex"
+        when: appletsContainer
+        value: {
+            if (root.inConfigureAppletsMode) {
+                return;
+            }
+
+            var ind = -1;
+            for (var i=0; i>=children[i].length-1; ++i){
+                if (children[i]
+                        && (children[i].index<ind || ind === -1)
+                        && children[i].applet
+                        && !children[i].isHidden
+                        && !children[i].isInternalViewSplitter) {
+                    ind = children[i].index;
+                }
+            }
+
+            return ind;
+        }
+    }
+
+    Binding{
+        target: appletsContainer
+        property:"lastVisibleIndex"
+        when: appletsContainer
+        value: {
+            if (root.inConfigureAppletsMode) {
+                return;
+            }
+
+            var ind = -1;
+            for (var i=children.length-1; i>=0; --i){
+                if (children[i]
+                        && children[i].index>ind
+                        && children[i].applet
+                        && !children[i].isHidden
+                        && !children[i].isInternalViewSplitter) {
+                    ind = children[i].index;
+                }
+            }
+
+            return ind;
+        }
+    }
+
     onCountChanged: {
         if (root.editMode) {
             //! this is mainly used when removing/adding internal view splitters