Resolves: tdf#108419 use spinfield preferred size as transparency widget size

Change-Id: I7b5c8aeb087efe007c687dc1f206bcb0e8b0173e
Reviewed-on: https://gerrit.libreoffice.org/38864Reviewed-by: Caolán McNamara <caolanm@redhat.com>
Tested-by: Caolán McNamara <caolanm@redhat.com>

svx/source/tbxctrls/grafctrl.cxx

@@ -92,11 +92,8 @@ ImplGrafMetricField::ImplGrafMetricField( vcl::Window* pParent, const OUString&
     maCommand( rCmd ),
     mxFrame( rFrame )
 {
-    Size aSize( GetTextWidth( "-100 %" ), GetTextHeight() );
-
-    aSize.Width() += 20;
-    aSize.Height() += 6;
-    SetSizePixel( aSize );
+    Size aSize(CalcMinimumSizeForText("-100 %"));
+    SetSizePixel(aSize);
 
     if ( maCommand == ".uno:GrafGamma" )
     {