reformat when the unit changes

Change-Id: I2252a5bc4c3b495c35b9d5672a272362646ebbe8
Reviewed-on: https://gerrit.libreoffice.org/63426
Tested-by: Jenkins
Reviewed-by: Caolán McNamara <caolanm@redhat.com>
Tested-by: Caolán McNamara <caolanm@redhat.com>

include/vcl/weld.hxx

@@ -824,11 +824,7 @@ public:
 
     FieldUnit get_unit() const { return m_eSrcUnit; }
 
-    void set_unit(FieldUnit eUnit)
-    {
-        m_eSrcUnit = eUnit;
-        update_width_chars();
-    }
+    void set_unit(FieldUnit eUnit);
 
     int convert_value_to(int nValue, FieldUnit eValueUnit) const
     {

vcl/source/window/builder.cxx

@@ -250,6 +250,18 @@ namespace weld
         m_xSpinButton->set_digits(digits);
         set_increments(step, page, m_eSrcUnit);
         set_value(value, m_eSrcUnit);
+        update_width_chars();
+    }
+
+    void MetricSpinButton::set_unit(FieldUnit eUnit)
+    {
+        int step, page;
+        get_increments(step, page, m_eSrcUnit);
+        int value = get_value(m_eSrcUnit);
+        m_eSrcUnit = eUnit;
+        set_increments(step, page, m_eSrcUnit);
+        set_value(value, m_eSrcUnit);
+        update_width_chars();
     }
 
     int MetricSpinButton::ConvertValue(int nValue, FieldUnit eInUnit, FieldUnit eOutUnit) const