added tiny (=minimal) button size, for high-dpi screens

CCBUG: 348399

kdecoration/breezedecoration.cpp

@@ -520,6 +520,7 @@ namespace Breeze
         const int baseSize = settings()->gridUnit();
         switch( m_internalSettings->buttonSize() )
         {
+            case InternalSettings::ButtonTiny: return baseSize;
             case InternalSettings::ButtonSmall: return baseSize*1.5;
             default:
             case InternalSettings::ButtonDefault: return baseSize*2;

kdecoration/breezesettingsdata.kcfg

@@ -62,6 +62,7 @@
     <!-- button size -->
     <entry name="ButtonSize" type="Enum">
       <choices>
+          <choice name="ButtonTiny" />
           <choice name="ButtonSmall" />
           <choice name="ButtonDefault" />
           <choice name="ButtonLarge" />

kdecoration/config/ui/breezeconfigurationui.ui

@@ -52,6 +52,11 @@
        </item>
        <item row="1" column="1">
         <widget class="QComboBox" name="buttonSize">
+         <item>
+          <property name="text">
+           <string>Tiny</string>
+          </property>
+         </item>
          <item>
           <property name="text">
            <string comment="@item:inlistbox Button size:">Small</string>