[SystemTray] Fix item size for very narrow panel

Summary:
For very narrow panel item size is too big (item + padding exceed panel size). This adds a check to not exceed panel size.
Before:
{F8167941}
After:
{F8167942}

Test Plan:
* Make panel very narrow - icons should fit into panel
* Repeat for vertical/horizontal

Reviewers: #plasma_workspaces, #plasma, ngraham, broulik

Reviewed By: ngraham

Subscribers: plasma-devel

Tags: #plasma

Differential Revision: https://phabricator.kde.org/D27958

applets/systemtray/package/contents/ui/items/PlasmoidItem.qml

@@ -54,7 +54,14 @@ AbstractItem {
 
     onHeightChanged: {
         if (applet) {
-            applet.width = height
+            applet.width = Math.min(plasmoidContainer.width, plasmoidContainer.height)
+            applet.height = applet.width
+        }
+    }
+    onWidthChanged: {
+        if (applet) {
+            applet.width = Math.min(plasmoidContainer.width, plasmoidContainer.height)
+            applet.height = applet.width
         }
     }
 
@@ -71,11 +78,10 @@ AbstractItem {
         if (applet) {
             applet.parent = plasmoidContainer
             applet.anchors.left = plasmoidContainer.left
-            applet.anchors.top = plasmoidContainer.top
-            applet.anchors.bottom = plasmoidContainer.bottom
-            applet.width = plasmoidContainer.height
+            applet.anchors.verticalCenter = plasmoidContainer.verticalCenter
+            applet.width = Math.min(plasmoidContainer.width, plasmoidContainer.height)
+            applet.height = applet.width
             applet.visible = true
-            plasmoidContainer.visible = true
 
             preloadFullRepresentationItem(applet.fullRepresentationItem)
         }

applets/systemtray/package/contents/ui/main.qml

@@ -154,8 +154,8 @@ MouseArea {
             interactive: false //disable features we don't need
             flow: vertical ? GridView.LeftToRight : GridView.TopToBottom
 
-            cellHeight: root.itemSize + units.smallSpacing
-            cellWidth: root.itemSize + units.smallSpacing
+            cellHeight: Math.min(root.itemSize + units.smallSpacing, root.height)
+            cellWidth: Math.min(root.itemSize + units.smallSpacing, root.width)
 
             readonly property int columns: !vertical ? Math.ceil(count / rows)
                                            : Math.max(1, Math.floor(root.width / cellWidth))