Units: stop newing Unit objects. pass around pointers to "undeletable" Unit objects in the UnitTable. I think we should move to using indexed units, and pass around the index of the unit in the unittable, or smth like that... ?

(bzr r12679)

19 files changed, 78 insertions, 78 deletions

diff --git a/src/ui/dialog/clonetiler.cpp b/src/ui/dialog/clonetiler.cpp
index b3675440b..87c399339 100644
--- a/src/ui/dialog/clonetiler.cpp
+++ b/src/ui/dialog/clonetiler.cpp
@@ -1107,7 +1107,7 @@ CloneTiler::CloneTiler (void) :
 #endif
 
                     double value = prefs->getDouble(prefs_path + "fillwidth", 50.0);
-                    Inkscape::Util::Unit const unit = unit_menu->getUnit();
+                    Inkscape::Util::Unit const *unit = unit_menu->getUnit();
                     gdouble const units = Inkscape::Util::Quantity::convert(value, "px", unit);
                     fill_width->set_value (units);
 
@@ -1140,7 +1140,7 @@ CloneTiler::CloneTiler (void) :
 #endif
 
                     double value = prefs->getDouble(prefs_path + "fillheight", 50.0);
-                    Inkscape::Util::Unit const unit = unit_menu->getUnit();
+                    Inkscape::Util::Unit const *unit = unit_menu->getUnit();
                     gdouble const units = Inkscape::Util::Quantity::convert(value, "px", unit);
                     fill_height->set_value (units);
 
@@ -2948,7 +2948,7 @@ void CloneTiler::clonetiler_switch_to_fill(GtkToggleButton * /*tb*/, GtkWidget *
 void CloneTiler::clonetiler_fill_width_changed(GtkAdjustment *adj, Inkscape::UI::Widget::UnitMenu *u)
 {
     gdouble const raw_dist = gtk_adjustment_get_value (adj);
-    Inkscape::Util::Unit const unit = u->getUnit();
+    Inkscape::Util::Unit const *unit = u->getUnit();
     gdouble const pixels = Inkscape::Util::Quantity::convert(raw_dist, unit, "px");
 
     Inkscape::Preferences *prefs = Inkscape::Preferences::get();
@@ -2958,7 +2958,7 @@ void CloneTiler::clonetiler_fill_width_changed(GtkAdjustment *adj, Inkscape::UI:
 void CloneTiler::clonetiler_fill_height_changed(GtkAdjustment *adj, Inkscape::UI::Widget::UnitMenu *u)
 {
     gdouble const raw_dist = gtk_adjustment_get_value (adj);
-    Inkscape::Util::Unit const unit = u->getUnit();
+    Inkscape::Util::Unit const *unit = u->getUnit();
     gdouble const pixels = Inkscape::Util::Quantity::convert(raw_dist, unit, "px");
 
     Inkscape::Preferences *prefs = Inkscape::Preferences::get();
@@ -2971,7 +2971,7 @@ void CloneTiler::clonetiler_unit_changed()
     gdouble width_pixels = prefs->getDouble(prefs_path + "fillwidth");
     gdouble height_pixels = prefs->getDouble(prefs_path + "fillheight");
     
-    Inkscape::Util::Unit unit = unit_menu->getUnit();
+    Inkscape::Util::Unit const *unit = unit_menu->getUnit();
     
     gdouble width_value = Inkscape::Util::Quantity::convert(width_pixels, "px", unit);
     gdouble height_value = Inkscape::Util::Quantity::convert(height_pixels, "px", unit);
diff --git a/src/ui/dialog/document-properties.cpp b/src/ui/dialog/document-properties.cpp
index 37d0ce213..a6019c55c 100644
--- a/src/ui/dialog/document-properties.cpp
+++ b/src/ui/dialog/document-properties.cpp
@@ -1441,7 +1441,7 @@ void DocumentProperties::update()
         _rum_deflt.setUnit (nv->doc_units->abbr);
 
     double doc_w = sp_desktop_document(dt)->getRoot()->width.value;
-    Glib::ustring doc_w_unit = unit_table.getUnit(sp_desktop_document(dt)->getRoot()->width.unit).abbr;
+    Glib::ustring doc_w_unit = unit_table.getUnit(sp_desktop_document(dt)->getRoot()->width.unit)->abbr;
     if (doc_w_unit == "") {
         doc_w_unit = "px";
     } else if (doc_w_unit == "%" && sp_desktop_document(dt)->getRoot()->viewBox_set) {
@@ -1449,7 +1449,7 @@ void DocumentProperties::update()
         doc_w = sp_desktop_document(dt)->getRoot()->viewBox.width();
     }
     double doc_h = sp_desktop_document(dt)->getRoot()->height.value;
-    Glib::ustring doc_h_unit = unit_table.getUnit(sp_desktop_document(dt)->getRoot()->height.unit).abbr;
+    Glib::ustring doc_h_unit = unit_table.getUnit(sp_desktop_document(dt)->getRoot()->height.unit)->abbr;
     if (doc_h_unit == "") {
         doc_h_unit = "px";
     } else if (doc_h_unit == "%" && sp_desktop_document(dt)->getRoot()->viewBox_set) {
@@ -1644,11 +1644,11 @@ void DocumentProperties::onDocUnitChange()
 {
     SPDocument *doc = SP_ACTIVE_DOCUMENT;
     Inkscape::XML::Node *repr = sp_desktop_namedview(getDesktop())->getRepr();
-    Inkscape::Util::Unit old_doc_unit = unit_table.getUnit("px");
+    Inkscape::Util::Unit const *old_doc_unit = unit_table.getUnit("px");
     if(repr->attribute("inkscape:document-units")) {
         old_doc_unit = unit_table.getUnit(repr->attribute("inkscape:document-units"));
     }
-    Inkscape::Util::Unit doc_unit = _rum_deflt.getUnit();
+    Inkscape::Util::Unit const *doc_unit = _rum_deflt.getUnit();
     
     // Don't execute when change is being undone
     if (!DocumentUndo::getUndoSensitive(doc)) {
@@ -1657,7 +1657,7 @@ void DocumentProperties::onDocUnitChange()
     
     // Set document unit
     Inkscape::SVGOStringStream os;
-    os << doc_unit.abbr;
+    os << doc_unit->abbr;
     repr->setAttribute("inkscape:document-units", os.str().c_str());
     
     // Set viewBox
diff --git a/src/ui/dialog/export.cpp b/src/ui/dialog/export.cpp
index 577793496..f1f7cf6c1 100644
--- a/src/ui/dialog/export.cpp
+++ b/src/ui/dialog/export.cpp
@@ -1884,7 +1884,7 @@ void Export::setValuePx(Glib::RefPtr<Gtk::Adjustment>& adj, double val)
 void Export::setValuePx( Gtk::Adjustment *adj, double val)
 #endif
 {
-    const Unit unit = unit_selector->getUnit();
+    Unit const *unit = unit_selector->getUnit();
 
     setValue(adj, Inkscape::Util::Quantity::convert(val, "px", unit));
 
@@ -1934,7 +1934,7 @@ float Export::getValuePx(  Gtk::Adjustment *adj )
 #endif
 {
     float value = getValue( adj);
-    const Unit unit = unit_selector->getUnit();
+    Unit const *unit = unit_selector->getUnit();
 
     return Inkscape::Util::Quantity::convert(value, unit, "px");
 } // end of sp_export_value_get_px()
diff --git a/src/ui/dialog/guides.cpp b/src/ui/dialog/guides.cpp
index 2de387364..5dfafa78d 100644
--- a/src/ui/dialog/guides.cpp
+++ b/src/ui/dialog/guides.cpp
@@ -59,7 +59,7 @@ Glib::ustring GuidelinePropertiesDialog::_angle_unit_status = DEG; // initialize
 GuidelinePropertiesDialog::~GuidelinePropertiesDialog() {
     // save current status
     _relative_toggle_status = _relative_toggle.get_active();
-    _angle_unit_status = _spin_angle.getUnit().abbr;
+    _angle_unit_status = _spin_angle.getUnit()->abbr;
 }
 
 void GuidelinePropertiesDialog::showDialog(SPGuide *guide, SPDesktop *desktop) {
diff --git a/src/ui/tool/node.cpp b/src/ui/tool/node.cpp
index 82eb697bd..76ec68c3e 100644
--- a/src/ui/tool/node.cpp
+++ b/src/ui/tool/node.cpp
@@ -493,9 +493,9 @@ Glib::ustring Handle::_getDragTip(GdkEventMotion */*event*/) const
     Inkscape::Util::Quantity x_q = Inkscape::Util::Quantity(dist[Geom::X], "px");
     Inkscape::Util::Quantity y_q = Inkscape::Util::Quantity(dist[Geom::Y], "px");
     Inkscape::Util::Quantity len_q = Inkscape::Util::Quantity(length(), "px");
-    GString *x = g_string_new(x_q.string(*_desktop->namedview->doc_units).c_str());
-    GString *y = g_string_new(y_q.string(*_desktop->namedview->doc_units).c_str());
-    GString *len = g_string_new(len_q.string(*_desktop->namedview->doc_units).c_str());
+    GString *x = g_string_new(x_q.string(_desktop->namedview->doc_units).c_str());
+    GString *y = g_string_new(y_q.string(_desktop->namedview->doc_units).c_str());
+    GString *len = g_string_new(len_q.string(_desktop->namedview->doc_units).c_str());
     Glib::ustring ret = format_tip(C_("Path handle tip",
         "Move handle by %s, %s; angle %.2f°, length %s"), x->str, y->str, angle, len->str);
     g_string_free(x, TRUE);
@@ -1300,10 +1300,9 @@ Glib::ustring Node::_getDragTip(GdkEventMotion */*event*/) const
     
     Inkscape::Util::Quantity x_q = Inkscape::Util::Quantity(dist[Geom::X], "px");
     Inkscape::Util::Quantity y_q = Inkscape::Util::Quantity(dist[Geom::Y], "px");
-    GString *x = g_string_new(x_q.string(*_desktop->namedview->doc_units).c_str());
-    GString *y = g_string_new(y_q.string(*_desktop->namedview->doc_units).c_str());
-    Glib::ustring ret = format_tip(C_("Path node tip", "Move node by %s, %s"),
-        x->str, y->str);
+    GString *x = g_string_new(x_q.string(_desktop->namedview->doc_units).c_str());
+    GString *y = g_string_new(y_q.string(_desktop->namedview->doc_units).c_str());
+    Glib::ustring ret = format_tip(C_("Path node tip", "Move node by %s, %s"), x->str, y->str);
     g_string_free(x, TRUE);
     g_string_free(y, TRUE);
     return ret;
diff --git a/src/ui/widget/page-sizer.cpp b/src/ui/widget/page-sizer.cpp
index 2379dc181..b13567adb 100644
--- a/src/ui/widget/page-sizer.cpp
+++ b/src/ui/widget/page-sizer.cpp
@@ -565,9 +565,8 @@ PageSizer::find_paper_size (Inkscape::Util::Quantity w, Inkscape::Util::Quantity
     for (iter = _paperSizeTable.begin() ;
          iter != _paperSizeTable.end() ; ++iter) {
         PaperSize paper = iter->second;
-        Inkscape::Util::Unit const &i_unit = paper.unit;
-        double smallX = Inkscape::Util::Quantity::convert(paper.smaller, i_unit, *w.unit);
-        double largeX = Inkscape::Util::Quantity::convert(paper.larger, i_unit, *w.unit);
+        double smallX = Inkscape::Util::Quantity::convert(paper.smaller, paper.unit, w.unit);
+        double largeX = Inkscape::Util::Quantity::convert(paper.larger, paper.unit, w.unit);
 
         g_return_val_if_fail(smallX <= largeX, _paperSizeListStore->children().end());
 
@@ -704,7 +703,7 @@ void
 PageSizer::on_value_changed()
 {
     if (_widgetRegistry->isUpdating()) return;
-    if (_unit != _dimensionUnits.getUnit().abbr) return;
+    if (_unit != _dimensionUnits.getUnit()->abbr) return;
     setDim (Inkscape::Util::Quantity(_dimensionWidth.getValue(""), _dimensionUnits.getUnit()),
             Inkscape::Util::Quantity(_dimensionHeight.getValue(""), _dimensionUnits.getUnit()));
 }
@@ -712,7 +711,7 @@ void
 PageSizer::on_units_changed()
 {
     if (_widgetRegistry->isUpdating()) return;
-    _unit = _dimensionUnits.getUnit().abbr;
+    _unit = _dimensionUnits.getUnit()->abbr;
     setDim (Inkscape::Util::Quantity(_dimensionWidth.getValue(""), _dimensionUnits.getUnit()),
             Inkscape::Util::Quantity(_dimensionHeight.getValue(""), _dimensionUnits.getUnit()));
 }
diff --git a/src/ui/widget/page-sizer.h b/src/ui/widget/page-sizer.h
index 95836a005..dc8e34d82 100644
--- a/src/ui/widget/page-sizer.h
+++ b/src/ui/widget/page-sizer.h
@@ -64,7 +64,7 @@ public:
     PaperSize(const Glib::ustring &nameArg,
 	          double smallerArg,
 	          double largerArg,
-			  Inkscape::Util::Unit unitArg)
+			  Inkscape::Util::Unit const *unitArg)
 	    {
 	    name    = nameArg;
 	    smaller = smallerArg;
@@ -108,7 +108,7 @@ public:
     /**
      * The units (px, pt, mm, etc) of this specification
      */	     
-    Inkscape::Util::Unit unit;
+    Inkscape::Util::Unit const *unit; /// pointer to object in UnitTable, do not delete
 
 private:
 
diff --git a/src/ui/widget/preferences-widget.cpp b/src/ui/widget/preferences-widget.cpp
index 567f29f91..3ba00c083 100644
--- a/src/ui/widget/preferences-widget.cpp
+++ b/src/ui/widget/preferences-widget.cpp
@@ -354,7 +354,7 @@ void PrefSpinUnit::on_my_value_changed()
     Inkscape::Preferences *prefs = Inkscape::Preferences::get();
     if (getWidget()->get_visible()) //only take action if user changed value
     {
-        prefs->setDoubleUnit(_prefs_path, getValue(getUnit().abbr), getUnit().abbr);
+        prefs->setDoubleUnit(_prefs_path, getValue(getUnit()->abbr), getUnit()->abbr);
     }
 }
 
diff --git a/src/ui/widget/registered-widget.h b/src/ui/widget/registered-widget.h
index 93b0cef4e..883a9e1a2 100644
--- a/src/ui/widget/registered-widget.h
+++ b/src/ui/widget/registered-widget.h
@@ -167,7 +167,7 @@ public:
                          SPDocument *doc_in = NULL );
 
     void setUnit (const Glib::ustring);
-    Unit getUnit() const { return static_cast<UnitMenu*>(_widget)->getUnit(); };
+    Unit const * getUnit() const { return static_cast<UnitMenu*>(_widget)->getUnit(); };
     UnitMenu* getUnitMenu() const { return static_cast<UnitMenu*>(_widget); };
     sigc::connection _changed_connection;
 
diff --git a/src/ui/widget/scalar-unit.cpp b/src/ui/widget/scalar-unit.cpp
index 2f4c1f341..4fa1a7584 100644
--- a/src/ui/widget/scalar-unit.cpp
+++ b/src/ui/widget/scalar-unit.cpp
@@ -102,7 +102,7 @@ void ScalarUnit::resetUnitType(UnitType unit_type)
     lastUnits = _unit_menu->getUnitAbbr();
 }
 
-Unit ScalarUnit::getUnit() const
+Unit const * ScalarUnit::getUnit() const
 {
     g_assert(_unit_menu != NULL);
     return _unit_menu->getUnit();
@@ -228,13 +228,13 @@ void ScalarUnit::on_unit_changed()
     Glib::ustring abbr = _unit_menu->getUnitAbbr();
     _suffix->set_label(abbr);
 
-    Inkscape::Util::Unit new_unit = (unit_table.getUnit(abbr));
-    Inkscape::Util::Unit old_unit = (unit_table.getUnit(lastUnits));
+    Inkscape::Util::Unit const *new_unit = unit_table.getUnit(abbr);
+    Inkscape::Util::Unit const *old_unit = unit_table.getUnit(lastUnits);
 
     double convertedVal = 0;
-    if (old_unit.type == UNIT_TYPE_DIMENSIONLESS && new_unit.type == UNIT_TYPE_LINEAR) {
+    if (old_unit->type == UNIT_TYPE_DIMENSIONLESS && new_unit->type == UNIT_TYPE_LINEAR) {
         convertedVal = PercentageToAbsolute(Scalar::getValue());
-    } else if (old_unit.type == UNIT_TYPE_LINEAR && new_unit.type == UNIT_TYPE_DIMENSIONLESS) {
+    } else if (old_unit->type == UNIT_TYPE_LINEAR && new_unit->type == UNIT_TYPE_DIMENSIONLESS) {
         convertedVal = AbsoluteToPercentage(Scalar::getValue());
     } else {
         double conversion = _unit_menu->getConversion(lastUnits);
diff --git a/src/ui/widget/scalar-unit.h b/src/ui/widget/scalar-unit.h
index 4f22f438c..9e310d3bd 100644
--- a/src/ui/widget/scalar-unit.h
+++ b/src/ui/widget/scalar-unit.h
@@ -82,7 +82,7 @@ public:
     /**
      * Gets the object for the currently selected unit.
      */
-    Unit      getUnit() const;
+    Unit const * getUnit() const;
 
     /**
      * Gets the UnitType ID for the unit.
diff --git a/src/ui/widget/selected-style.cpp b/src/ui/widget/selected-style.cpp
index 97581aa83..3a6b0c7df 100644
--- a/src/ui/widget/selected-style.cpp
+++ b/src/ui/widget/selected-style.cpp
@@ -315,8 +315,8 @@ SelectedStyle::SelectedStyle(bool /*layout*/)
             Gtk::RadioMenuItem *mi = Gtk::manage(new Gtk::RadioMenuItem(_sw_group));
             mi->add(*(new Gtk::Label(iter->first, 0.0, 0.5)));
             _unit_mis = g_slist_append(_unit_mis, mi);
-            Inkscape::Util::Unit const *u = new Inkscape::Util::Unit(unit_table.getUnit(iter->first));
-            mi->signal_activate().connect(sigc::bind<Inkscape::Util::Unit>(sigc::mem_fun(*this, &SelectedStyle::on_popup_units), *u));
+            Inkscape::Util::Unit const *u = unit_table.getUnit(iter->first);
+            mi->signal_activate().connect(sigc::bind<Inkscape::Util::Unit const *>(sigc::mem_fun(*this, &SelectedStyle::on_popup_units), u));
             _popup_sw.attach(*mi, 0,1, row, row+1);
             row++;
             ++iter;
@@ -481,7 +481,7 @@ SelectedStyle::setDesktop(SPDesktop *desktop)
             this )
     ));
 
-    _sw_unit = const_cast<Inkscape::Util::Unit*>(sp_desktop_namedview(desktop)->doc_units);
+    _sw_unit = sp_desktop_namedview(desktop)->doc_units;
 
     // Set the doc default unit active in the units list
     gint length = g_slist_length(_unit_mis);
@@ -931,8 +931,8 @@ SelectedStyle::on_opacity_click(GdkEventButton *event)
     return false;
 }
 
-void SelectedStyle::on_popup_units(Inkscape::Util::Unit &unit) {
-    _sw_unit = new Inkscape::Util::Unit(unit);
+void SelectedStyle::on_popup_units(Inkscape::Util::Unit const *unit) {
+    _sw_unit = unit;
     update();
 }
 
@@ -940,7 +940,7 @@ void SelectedStyle::on_popup_preset(int i) {
     SPCSSAttr *css = sp_repr_css_attr_new ();
     gdouble w;
     if (_sw_unit) {
-        w = Inkscape::Util::Quantity::convert(_sw_presets[i], *_sw_unit, "px");
+        w = Inkscape::Util::Quantity::convert(_sw_presets[i], _sw_unit, "px");
     } else {
         w = _sw_presets[i];
     }
@@ -1119,7 +1119,7 @@ SelectedStyle::update()
     {
         double w;
         if (_sw_unit) {
-            w = Inkscape::Util::Quantity::convert(query->stroke_width.computed, "px", *_sw_unit);
+            w = Inkscape::Util::Quantity::convert(query->stroke_width.computed, "px", _sw_unit);
         } else {
             w = query->stroke_width.computed;
         }
diff --git a/src/ui/widget/selected-style.h b/src/ui/widget/selected-style.h
index 0a907f1fd..21e5575ed 100644
--- a/src/ui/widget/selected-style.h
+++ b/src/ui/widget/selected-style.h
@@ -276,11 +276,11 @@ protected:
     Gtk::Menu _popup_sw; 
     Gtk::RadioButtonGroup _sw_group;
     GSList *_unit_mis;
-    void on_popup_units(Inkscape::Util::Unit &u);
+    void on_popup_units(Inkscape::Util::Unit const *u);
     void on_popup_preset(int i);
     Gtk::MenuItem _popup_sw_remove;
 
-    Inkscape::Util::Unit *_sw_unit;
+    Inkscape::Util::Unit const *_sw_unit;  /// points to object in UnitTable, do not delete
 
     void *_drop[2];
     bool _dropEnabled[2];
diff --git a/src/ui/widget/spinbutton.cpp b/src/ui/widget/spinbutton.cpp
index 1114ff32b..6cbc15c1b 100644
--- a/src/ui/widget/spinbutton.cpp
+++ b/src/ui/widget/spinbutton.cpp
@@ -35,16 +35,16 @@ int SpinButton::on_input(double* newvalue)
     try {
         Inkscape::Util::EvaluatorQuantity result;
         if (_unit_menu || _unit_tracker) {
-            Unit unit;
+            Unit const *unit = NULL;
             if (_unit_menu) {
                 unit = _unit_menu->getUnit();
             } else {
                 unit = _unit_tracker->getActiveUnit();
             }
-            Inkscape::Util::ExpressionEvaluator eval = Inkscape::Util::ExpressionEvaluator(get_text().c_str(), &unit);
+            Inkscape::Util::ExpressionEvaluator eval = Inkscape::Util::ExpressionEvaluator(get_text().c_str(), unit);
             result = eval.evaluate();
             // check if output dimension corresponds to input unit
-            if (result.dimension != (unit.isAbsolute() ? 1 : 0) ) {
+            if (result.dimension != (unit->isAbsolute() ? 1 : 0) ) {
                 throw Inkscape::Util::EvaluatorException("Input dimensions do not match with parameter dimensions.","");
             }
         } else {
diff --git a/src/ui/widget/style-swatch.cpp b/src/ui/widget/style-swatch.cpp
index 49466ce54..a33c1d09f 100644
--- a/src/ui/widget/style-swatch.cpp
+++ b/src/ui/widget/style-swatch.cpp
@@ -333,7 +333,7 @@ void StyleSwatch::setStyle(SPStyle *query)
     if (has_stroke) {
         double w;
         if (_sw_unit) {
-            w = Inkscape::Util::Quantity::convert(query->stroke_width.computed, "px", *_sw_unit);
+            w = Inkscape::Util::Quantity::convert(query->stroke_width.computed, "px", _sw_unit);
         } else {
             w = query->stroke_width.computed;
         }
diff --git a/src/ui/widget/unit-menu.cpp b/src/ui/widget/unit-menu.cpp
index 684016471..7416a2f02 100644
--- a/src/ui/widget/unit-menu.cpp
+++ b/src/ui/widget/unit-menu.cpp
@@ -56,7 +56,7 @@ void UnitMenu::addUnit(Unit const& u)
     append(u.abbr);
 }
 
-Unit UnitMenu::getUnit() const
+Unit const * UnitMenu::getUnit() const
 {
     if (get_active_text() == "") {
         g_assert(_type != UNIT_TYPE_NONE);
@@ -79,27 +79,27 @@ Glib::ustring UnitMenu::getUnitAbbr() const
     if (get_active_text() == "") {
         return "";
     }
-    return getUnit().abbr;
+    return getUnit()->abbr;
 }
 
 UnitType UnitMenu::getUnitType() const
 {
-    return getUnit().type;
+    return getUnit()->type;
 }
 
 double  UnitMenu::getUnitFactor() const
 {
-    return getUnit().factor;
+    return getUnit()->factor;
 }
 
 int UnitMenu::getDefaultDigits() const
 {
-    return getUnit().defaultDigits();
+    return getUnit()->defaultDigits();
 }
 
 double UnitMenu::getDefaultStep() const
 { 
-    int factor_digits = -1*int(log10(getUnit().factor));
+    int factor_digits = -1*int(log10(getUnit()->factor));
     return pow(10.0, factor_digits);
 }
 
@@ -110,19 +110,20 @@ double UnitMenu::getDefaultPage() const
 
 double UnitMenu::getConversion(Glib::ustring const &new_unit_abbr, Glib::ustring const &old_unit_abbr) const
 {
-    double old_factor = getUnit().factor;
-    if (old_unit_abbr != "no_unit")
-        old_factor = unit_table.getUnit(old_unit_abbr).factor;
-    Unit new_unit = unit_table.getUnit(new_unit_abbr);
+    double old_factor = getUnit()->factor;
+    if (old_unit_abbr != "no_unit") {
+        old_factor = unit_table.getUnit(old_unit_abbr)->factor;
+    }
+    Unit const * new_unit = unit_table.getUnit(new_unit_abbr);
 
     // Catch the case of zero or negative unit factors (error!)
     if (old_factor < 0.0000001 ||
-        new_unit.factor < 0.0000001) {
+        new_unit->factor < 0.0000001) {
         // TODO:  Should we assert here?
         return 0.00;
     }
 
-    return old_factor / new_unit.factor;
+    return old_factor / new_unit->factor;
 }
 
 bool UnitMenu::isAbsolute() const
diff --git a/src/ui/widget/unit-menu.h b/src/ui/widget/unit-menu.h
index 3f4df6bf9..114c536c9 100644
--- a/src/ui/widget/unit-menu.h
+++ b/src/ui/widget/unit-menu.h
@@ -74,7 +74,7 @@ public:
      * Returns the Unit object corresponding to the current selection
      * in the dropdown widget.
      */
-    Unit          getUnit() const;
+    Unit const *  getUnit() const;
 
     /**
      * Returns the abbreviated unit name of the selected unit.
diff --git a/src/ui/widget/unit-tracker.cpp b/src/ui/widget/unit-tracker.cpp
index 155f3fafe..67eb1f48d 100644
--- a/src/ui/widget/unit-tracker.cpp
+++ b/src/ui/widget/unit-tracker.cpp
@@ -27,6 +27,7 @@ namespace Widget {
 UnitTracker::UnitTracker(UnitType unit_type) :
     _active(0),
     _isUpdating(false),
+    _activeUnit(NULL),
     _activeUnitInitialized(false),
     _store(0),
     _unitList(0),
@@ -74,7 +75,7 @@ bool UnitTracker::isUpdating() const
     return _isUpdating;
 }
 
-Inkscape::Util::Unit UnitTracker::getActiveUnit() const
+Inkscape::Util::Unit const * UnitTracker::getActiveUnit() const
 {
     return _activeUnit;
 }
@@ -101,8 +102,8 @@ void UnitTracker::setActiveUnit(Inkscape::Util::Unit const *unit)
 
 void UnitTracker::setActiveUnitByAbbr(gchar const *abbr)
 {
-    Inkscape::Util::Unit u = unit_table.getUnit(abbr);
-    setActiveUnit(&u);
+    Inkscape::Util::Unit const *u = unit_table.getUnit(abbr);
+    setActiveUnit(u);
 }
 
 void UnitTracker::addAdjustment(GtkAdjustment *adj)
@@ -113,11 +114,11 @@ void UnitTracker::addAdjustment(GtkAdjustment *adj)
     }
 }
 
-void UnitTracker::addUnit(Inkscape::Util::Unit const &u)
+void UnitTracker::addUnit(Inkscape::Util::Unit const *u)
 {
     GtkTreeIter iter;
     gtk_list_store_append(_store, &iter);
-    gtk_list_store_set(_store, &iter, COLUMN_STRING, u.abbr.c_str(), -1);
+    gtk_list_store_set(_store, &iter, COLUMN_STRING, u ? u->abbr.c_str() : "NULL", -1);
 }
 
 void UnitTracker::setFullVal(GtkAdjustment *adj, gdouble val)
@@ -197,13 +198,13 @@ void UnitTracker::_setActive(gint active)
         if (found) {
             gchar *abbr;
             gtk_tree_model_get(GTK_TREE_MODEL(_store), &iter, COLUMN_STRING, &abbr, -1);
-            Inkscape::Util::Unit unit = unit_table.getUnit(abbr);
+            Inkscape::Util::Unit const *unit = unit_table.getUnit(abbr);
 
             found = gtk_tree_model_iter_nth_child(GTK_TREE_MODEL(_store), &iter, NULL, active);
             if (found) {
                 gchar *newAbbr;
                 gtk_tree_model_get(GTK_TREE_MODEL(_store), &iter, COLUMN_STRING, &newAbbr, -1);
-                Inkscape::Util::Unit newUnit = unit_table.getUnit(newAbbr);
+                Inkscape::Util::Unit const *newUnit = unit_table.getUnit(newAbbr);
                 _activeUnit = newUnit;
 
                 if (_adjList) {
@@ -230,7 +231,7 @@ void UnitTracker::_setActive(gint active)
     }
 }
 
-void UnitTracker::_fixupAdjustments(Inkscape::Util::Unit const oldUnit, Inkscape::Util::Unit const newUnit)
+void UnitTracker::_fixupAdjustments(Inkscape::Util::Unit const *oldUnit, Inkscape::Util::Unit const *newUnit)
 {
     _isUpdating = true;
     for ( GSList *cur = _adjList ; cur ; cur = g_slist_next(cur) ) {
@@ -238,13 +239,13 @@ void UnitTracker::_fixupAdjustments(Inkscape::Util::Unit const oldUnit, Inkscape
         gdouble oldVal = gtk_adjustment_get_value(adj);
         gdouble val = oldVal;
 
-        if ( (oldUnit.type != Inkscape::Util::UNIT_TYPE_DIMENSIONLESS)
-            && (newUnit.type == Inkscape::Util::UNIT_TYPE_DIMENSIONLESS) )
+        if ( (oldUnit->type != Inkscape::Util::UNIT_TYPE_DIMENSIONLESS)
+            && (newUnit->type == Inkscape::Util::UNIT_TYPE_DIMENSIONLESS) )
         {
-            val = newUnit.factor * 100;
+            val = newUnit->factor * 100;
             _priorValues[adj] = Inkscape::Util::Quantity::convert(oldVal, oldUnit, "px");
-        } else if ( (oldUnit.type == Inkscape::Util::UNIT_TYPE_DIMENSIONLESS)
-            && (newUnit.type != Inkscape::Util::UNIT_TYPE_DIMENSIONLESS) )
+        } else if ( (oldUnit->type == Inkscape::Util::UNIT_TYPE_DIMENSIONLESS)
+            && (newUnit->type != Inkscape::Util::UNIT_TYPE_DIMENSIONLESS) )
         {
             if (_priorValues.find(adj) != _priorValues.end()) {
                 val = Inkscape::Util::Quantity::convert(_priorValues[adj], "px", newUnit);
diff --git a/src/ui/widget/unit-tracker.h b/src/ui/widget/unit-tracker.h
index 19559ae1c..61bb556ef 100644
--- a/src/ui/widget/unit-tracker.h
+++ b/src/ui/widget/unit-tracker.h
@@ -36,9 +36,9 @@ public:
 
     void setActiveUnit(Inkscape::Util::Unit const *unit);
     void setActiveUnitByAbbr(gchar const *abbr);
-    Inkscape::Util::Unit getActiveUnit() const;
+    Inkscape::Util::Unit const * getActiveUnit() const;
 
-    void addUnit(Inkscape::Util::Unit const &u);
+    void addUnit(Inkscape::Util::Unit const *u);
     void addAdjustment(GtkAdjustment *adj);
     void setFullVal(GtkAdjustment *adj, gdouble val);
 
@@ -52,13 +52,13 @@ private:
     static void _actionFinalizedCB(gpointer data, GObject *where_the_object_was);
     static void _adjustmentFinalizedCB(gpointer data, GObject *where_the_object_was);
     void _setActive(gint index);
-    void _fixupAdjustments(Inkscape::Util::Unit const oldUnit, Inkscape::Util::Unit const newUnit);
+    void _fixupAdjustments(Inkscape::Util::Unit const *oldUnit, Inkscape::Util::Unit const *newUnit);
     void _actionFinalized(GObject *where_the_object_was);
     void _adjustmentFinalized(GObject *where_the_object_was);
 
     gint _active;
     bool _isUpdating;
-    Inkscape::Util::Unit _activeUnit;
+    Inkscape::Util::Unit const *_activeUnit;
     bool _activeUnitInitialized;
     GtkListStore *_store;
     GSList *_unitList;