Make system tray icon sizes configurable by the user.
See also Bug #364431 https://bugs.kde.org/show_bug.cgi?id=364431
See also Bug #365570 https://bugs.kde.org/show_bug.cgi?id=365570

diff --git a/applets/systemtray/package/contents/code/IconSizeTools.js b/applets/systemtray/package/contents/code/IconSizeTools.js
new file mode 100644
index 0000000..7d06349
--- /dev/null
+++ b/applets/systemtray/package/contents/code/IconSizeTools.js
@@ -0,0 +1,5 @@
+var iconSizes = new Array("small", "smallMedium", "medium", "large", "huge", "enormous");
+
+function iconSizeFromTheme(size) {
+    return units.iconSizes[iconSizes[size]];
+}
diff --git a/applets/systemtray/package/contents/config/main.xml b/applets/systemtray/package/contents/config/main.xml
index 65a7029..f0defc3 100644
--- a/applets/systemtray/package/contents/config/main.xml
+++ b/applets/systemtray/package/contents/config/main.xml
@@ -45,6 +45,9 @@
     <entry name="knownItems" type="StringList">
       <default></default>
     </entry>
+    <entry name="iconSize" type="Int">
+      <default>2</default>
+    </entry>
   </group>

 </kcfg>
diff --git a/applets/systemtray/package/contents/ui/ConfigGeneral.qml b/applets/systemtray/package/contents/ui/ConfigGeneral.qml
index 4fcfcf6..ec6885b 100644
--- a/applets/systemtray/package/contents/ui/ConfigGeneral.qml
+++ b/applets/systemtray/package/contents/ui/ConfigGeneral.qml
@@ -42,5 +42,6 @@ Item {
     property alias cfg_hardwareControlShown: hardwareControl.checked
     property alias cfg_miscellaneousShown: miscellaneous.checked
+    property alias cfg_iconSize: iconSize.value
     property var cfg_extraItems: []

     SystemPalette {
@@ -52,6 +54,39 @@ Item {

         PlasmaExtras.Heading {
             level: 2
+            text: i18n("Icon Size")
+            color: palette.text
+        }
+        Item {
+            width: height
+            height: units.gridUnit / 2
+        }
+        QtLayouts.RowLayout {
+            visible: !isPopup || viewMode.currentIndex === 1
+            QtControls.Label {
+                text: i18n("Size:")
+            }
+            QtControls.Label {
+                text: i18n("Small")
+            }
+            QtControls.Slider {
+                id: iconSize
+                minimumValue: 0
+                maximumValue: 5
+                stepSize: 1
+                tickmarksEnabled: true
+            }
+            QtControls.Label {
+                text: i18n("Large")
+            }
+        }
+
+        Item {
+            width: height
+            height: units.gridUnit
+        }
+        PlasmaExtras.Heading {
+            level: 2
             text: i18n("Categories")
             color: palette.text
         }
diff --git a/applets/systemtray/package/contents/ui/main.qml b/applets/systemtray/package/contents/ui/main.qml
index a66ea69..d0a1e04 100644
--- a/applets/systemtray/package/contents/ui/main.qml
+++ b/applets/systemtray/package/contents/ui/main.qml
@@ -22,5 +22,6 @@ import QtQuick 2.5
 import org.kde.plasma.core 2.0 as PlasmaCore
 import org.kde.plasma.plasmoid 2.0
+import "IconSizeTools.js" as IconSizeTools
 import "items"

 MouseArea {
@@ -34,4 +35,4 @@ MouseArea {
     property bool vertical: plasmoid.formFactor == PlasmaCore.Types.Vertical
-    property int itemSize: units.roundToIconSize(Math.min(Math.min(width, height), units.iconSizes[iconSizes[plasmoid.configuration.iconSize]]))
-    property int hiddenItemSize: units.iconSizes.smallMedium
+    property int itemSize: units.roundToIconSize(Math.min(Math.min(width, height), IconSizeTools.iconSizeFromTheme(plasmoid.configuration.iconSize)))
+    property int hiddenItemSize: Math.min(units.iconSizes.large, IconSizeTools.iconSizeFromTheme(plasmoid.configuration.iconSize))
     property alias expanded: dialog.visible