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)

54 files changed, 268 insertions, 270 deletions

diff --git a/src/arc-context.cpp b/src/arc-context.cpp
index dc869ce60..a14562a32 100644
--- a/src/arc-context.cpp
+++ b/src/arc-context.cpp
@@ -418,8 +418,8 @@ void SPArcContext::drag(Geom::Point pt, guint state) {
 
     Inkscape::Util::Quantity rdimx_q = Inkscape::Util::Quantity(rdimx, "px");
     Inkscape::Util::Quantity rdimy_q = Inkscape::Util::Quantity(rdimy, "px");
-    GString *xs = g_string_new(rdimx_q.string(*desktop->namedview->doc_units).c_str());
-    GString *ys = g_string_new(rdimy_q.string(*desktop->namedview->doc_units).c_str());
+    GString *xs = g_string_new(rdimx_q.string(desktop->namedview->doc_units).c_str());
+    GString *ys = g_string_new(rdimy_q.string(desktop->namedview->doc_units).c_str());
 
     if (state & GDK_CONTROL_MASK) {
         int ratio_x, ratio_y;
diff --git a/src/display/canvas-axonomgrid.cpp b/src/display/canvas-axonomgrid.cpp
index 654144122..d66b97bbc 100644
--- a/src/display/canvas-axonomgrid.cpp
+++ b/src/display/canvas-axonomgrid.cpp
@@ -161,15 +161,16 @@ CanvasAxonomGrid::CanvasAxonomGrid (SPNamedView * nv, Inkscape::XML::Node * in_r
     : CanvasGrid(nv, in_repr, in_doc, GRID_AXONOMETRIC)
 {
     Inkscape::Preferences *prefs = Inkscape::Preferences::get();
-    gridunit = new Inkscape::Util::Unit(unit_table.getUnit(prefs->getString("/options/grids/axonom/units")));
-    if (!gridunit)
-        gridunit = new Inkscape::Util::Unit(unit_table.getUnit("px"));
-    origin[Geom::X] = Inkscape::Util::Quantity::convert(prefs->getDouble("/options/grids/axonom/origin_x", 0.0), *gridunit, "px");
-    origin[Geom::Y] = Inkscape::Util::Quantity::convert(prefs->getDouble("/options/grids/axonom/origin_y", 0.0), *gridunit, "px");
+    gridunit = unit_table.getUnit(prefs->getString("/options/grids/axonom/units"));
+    if (!gridunit) {
+        gridunit = unit_table.getUnit("px");
+    }
+    origin[Geom::X] = Inkscape::Util::Quantity::convert(prefs->getDouble("/options/grids/axonom/origin_x", 0.0), gridunit, "px");
+    origin[Geom::Y] = Inkscape::Util::Quantity::convert(prefs->getDouble("/options/grids/axonom/origin_y", 0.0), gridunit, "px");
     color = prefs->getInt("/options/grids/axonom/color", 0x0000ff20);
     empcolor = prefs->getInt("/options/grids/axonom/empcolor", 0x0000ff40);
     empspacing = prefs->getInt("/options/grids/axonom/empspacing", 5);
-    lengthy = Inkscape::Util::Quantity::convert(prefs->getDouble("/options/grids/axonom/spacing_y", 1.0), *gridunit, "px");
+    lengthy = Inkscape::Util::Quantity::convert(prefs->getDouble("/options/grids/axonom/spacing_y", 1.0), gridunit, "px");
     angle_deg[X] = prefs->getDouble("/options/grids/axonom/angle_x", 30.0);
     angle_deg[Z] = prefs->getDouble("/options/grids/axonom/angle_z", 30.0);
     angle_deg[Y] = 0;
@@ -370,13 +371,13 @@ _wr.setUpdating (false);
 
     gdouble val;
     val = origin[Geom::X];
-    val = Inkscape::Util::Quantity::convert(val, "px", *gridunit);
+    val = Inkscape::Util::Quantity::convert(val, "px", gridunit);
     _rsu_ox->setValue (val);
     val = origin[Geom::Y];
-    val = Inkscape::Util::Quantity::convert(val, "px", *gridunit);
+    val = Inkscape::Util::Quantity::convert(val, "px", gridunit);
     _rsu_oy->setValue (val);
     val = lengthy;
-    double gridy = Inkscape::Util::Quantity::convert(val, "px", *gridunit);
+    double gridy = Inkscape::Util::Quantity::convert(val, "px", gridunit);
     _rsu_sy->setValue (gridy);
 
     _rsu_ax->setValue(angle_deg[X]);
diff --git a/src/display/canvas-grid.cpp b/src/display/canvas-grid.cpp
index 5701b91a1..192cc4cba 100644
--- a/src/display/canvas-grid.cpp
+++ b/src/display/canvas-grid.cpp
@@ -399,10 +399,10 @@ void CanvasGrid::setOrigin(Geom::Point const &origin_px)
     gdouble val;
 
     val = origin_px[Geom::X];
-    val = Inkscape::Util::Quantity::convert(val, "px", *gridunit);
+    val = Inkscape::Util::Quantity::convert(val, "px", gridunit);
     os_x << val << gridunit->abbr;
     val = origin_px[Geom::Y];
-    val = Inkscape::Util::Quantity::convert(val, "px", *gridunit);
+    val = Inkscape::Util::Quantity::convert(val, "px", gridunit);
     os_y << val << gridunit->abbr;
     repr->setAttribute("originx", os_x.str().c_str());
     repr->setAttribute("originy", os_y.str().c_str());
@@ -489,17 +489,17 @@ CanvasXYGrid::CanvasXYGrid (SPNamedView * nv, Inkscape::XML::Node * in_repr, SPD
     : CanvasGrid(nv, in_repr, in_doc, GRID_RECTANGULAR)
 {
     Inkscape::Preferences *prefs = Inkscape::Preferences::get();
-    gridunit = new Inkscape::Util::Unit(unit_table.getUnit(prefs->getString("/options/grids/xy/units")));
+    gridunit = unit_table.getUnit(prefs->getString("/options/grids/xy/units"));
     if (!gridunit) {
-        gridunit = new Inkscape::Util::Unit(unit_table.getUnit("px"));
+        gridunit = unit_table.getUnit("px");
     }
-    origin[Geom::X] = Inkscape::Util::Quantity::convert(prefs->getDouble("/options/grids/xy/origin_x", 0.0), *gridunit, "px");
-    origin[Geom::Y] = Inkscape::Util::Quantity::convert(prefs->getDouble("/options/grids/xy/origin_y", 0.0), *gridunit, "px");
+    origin[Geom::X] = Inkscape::Util::Quantity::convert(prefs->getDouble("/options/grids/xy/origin_x", 0.0), gridunit, "px");
+    origin[Geom::Y] = Inkscape::Util::Quantity::convert(prefs->getDouble("/options/grids/xy/origin_y", 0.0), gridunit, "px");
     color = prefs->getInt("/options/grids/xy/color", 0x0000ff20);
     empcolor = prefs->getInt("/options/grids/xy/empcolor", 0x0000ff40);
     empspacing = prefs->getInt("/options/grids/xy/empspacing", 5);
-    spacing[Geom::X] = Inkscape::Util::Quantity::convert(prefs->getDouble("/options/grids/xy/spacing_x", 0.0), *gridunit, "px");
-    spacing[Geom::Y] = Inkscape::Util::Quantity::convert(prefs->getDouble("/options/grids/xy/spacing_y", 0.0), *gridunit, "px");
+    spacing[Geom::X] = Inkscape::Util::Quantity::convert(prefs->getDouble("/options/grids/xy/spacing_x", 0.0), gridunit, "px");
+    spacing[Geom::Y] = Inkscape::Util::Quantity::convert(prefs->getDouble("/options/grids/xy/spacing_y", 0.0), gridunit, "px");
     render_dotted = prefs->getBool("/options/grids/xy/dotted", false);
 
     snapper = new CanvasXYGridSnapper(this, &namedview->snap_manager, 0);
@@ -605,7 +605,7 @@ CanvasXYGrid::readRepr()
         gridunit = q.unit;
         spacing[Geom::X] = q.quantity;
         validateScalar(oldVal, &spacing[Geom::X]);
-        spacing[Geom::X] = Inkscape::Util::Quantity::convert(spacing[Geom::X], *gridunit, "px");
+        spacing[Geom::X] = Inkscape::Util::Quantity::convert(spacing[Geom::X], gridunit, "px");
     }
     if ( (value = repr->attribute("spacingy")) ) {
         double oldVal = spacing[Geom::Y];
@@ -613,7 +613,7 @@ CanvasXYGrid::readRepr()
         gridunit = q.unit;
         spacing[Geom::Y] = q.quantity;
         validateScalar(oldVal, &spacing[Geom::Y]);
-        spacing[Geom::Y] = Inkscape::Util::Quantity::convert(spacing[Geom::Y], *gridunit, "px");
+        spacing[Geom::Y] = Inkscape::Util::Quantity::convert(spacing[Geom::Y], gridunit, "px");
     }
 
     if ( (value = repr->attribute("color")) ) {
@@ -753,16 +753,16 @@ CanvasXYGrid::newSpecificWidget()
 
     gdouble val;
     val = origin[Geom::X];
-    val = Inkscape::Util::Quantity::convert(val, "px", *gridunit);
+    val = Inkscape::Util::Quantity::convert(val, "px", gridunit);
     _rsu_ox->setValue (val);
     val = origin[Geom::Y];
-    val = Inkscape::Util::Quantity::convert(val, "px", *gridunit);
+    val = Inkscape::Util::Quantity::convert(val, "px", gridunit);
     _rsu_oy->setValue (val);
     val = spacing[Geom::X];
-    double gridx = Inkscape::Util::Quantity::convert(val, "px", *gridunit);
+    double gridx = Inkscape::Util::Quantity::convert(val, "px", gridunit);
     _rsu_sx->setValue (gridx);
     val = spacing[Geom::Y];
-    double gridy = Inkscape::Util::Quantity::convert(val, "px", *gridunit);
+    double gridy = Inkscape::Util::Quantity::convert(val, "px", gridunit);
     _rsu_sy->setValue (gridy);
 
     _rcp_gcol->setRgba32 (color);
diff --git a/src/display/canvas-grid.h b/src/display/canvas-grid.h
index 56ed86e94..078670da7 100644
--- a/src/display/canvas-grid.h
+++ b/src/display/canvas-grid.h
@@ -92,7 +92,7 @@ public:
     guint32 empcolor;     /**< Color for emphasis lines */
     gint empspacing;      /**< Spacing between emphasis lines */
 
-    Inkscape::Util::Unit const* gridunit;
+    Inkscape::Util::Unit const* gridunit;  /**< points to Unit object in UnitTable (so don't delete it) */
 
     Inkscape::XML::Node * repr;
     SPDocument *doc;
diff --git a/src/document.cpp b/src/document.cpp
index b94b72bda..4f57cf080 100644
--- a/src/document.cpp
+++ b/src/document.cpp
@@ -556,8 +556,8 @@ SPDocument *SPDocument::doUnref()
 
 Inkscape::Util::Quantity SPDocument::getWidth() const
 {
-    g_return_val_if_fail(this->priv != NULL, Inkscape::Util::Quantity(0.0, Inkscape::Util::Unit()));
-    g_return_val_if_fail(this->root != NULL, Inkscape::Util::Quantity(0.0, Inkscape::Util::Unit()));
+    g_return_val_if_fail(this->priv != NULL, Inkscape::Util::Quantity(0.0, unit_table.getUnit("")));
+    g_return_val_if_fail(this->root != NULL, Inkscape::Util::Quantity(0.0, unit_table.getUnit("")));
 
     gdouble result = root->width.value;
     SVGLength::Unit u = root->width.unit;
@@ -577,7 +577,7 @@ void SPDocument::setWidth(const Inkscape::Util::Quantity &width)
     root->width.computed = width.value("px");
     /* SVG does not support meters as a unit, so we must translate meters to
      * cm when writing */
-    if (*width.unit == unit_table.getUnit("m")) {
+    if (*width.unit == *unit_table.getUnit("m")) {
         root->width.value = width.value("cm");
         root->width.unit = SVGLength::CM;
     } else {
@@ -593,8 +593,8 @@ void SPDocument::setWidth(const Inkscape::Util::Quantity &width)
 
 Inkscape::Util::Quantity SPDocument::getHeight() const
 {
-    g_return_val_if_fail(this->priv != NULL, Inkscape::Util::Quantity(0.0, Inkscape::Util::Unit()));
-    g_return_val_if_fail(this->root != NULL, Inkscape::Util::Quantity(0.0, Inkscape::Util::Unit()));
+    g_return_val_if_fail(this->priv != NULL, Inkscape::Util::Quantity(0.0, unit_table.getUnit("")));
+    g_return_val_if_fail(this->root != NULL, Inkscape::Util::Quantity(0.0, unit_table.getUnit("")));
 
     gdouble result = root->height.value;
     SVGLength::Unit u = root->height.unit;
@@ -614,7 +614,7 @@ void SPDocument::setHeight(const Inkscape::Util::Quantity &height)
     root->height.computed = height.value("px");
     /* SVG does not support meters as a unit, so we must translate meters to
      * cm when writing */
-    if (*height.unit == unit_table.getUnit("m")) {
+    if (*height.unit == *unit_table.getUnit("m")) {
         root->height.value = height.value("cm");
         root->height.unit = SVGLength::CM;
     } else {
@@ -660,7 +660,7 @@ void SPDocument::fitToRect(Geom::Rect const &rect, bool with_margins)
     double const h = rect.height();
 
     double const old_height = getHeight().value("px");
-    Inkscape::Util::Unit const px = unit_table.getUnit("px");
+    Inkscape::Util::Unit const *px = unit_table.getUnit("px");
     
     /* in px */
     double margin_top = 0.0;
@@ -674,17 +674,16 @@ void SPDocument::fitToRect(Geom::Rect const &rect, bool with_margins)
         if (nv != NULL) {
             gchar const * const units_abbr = nv->getAttribute("units");
             Inkscape::Util::Unit const *margin_units = NULL;
-            if (units_abbr != NULL) {
-                Inkscape::Util::Unit mu = unit_table.getUnit(units_abbr);
-                margin_units = &mu;
+            if (units_abbr) {
+                margin_units = unit_table.getUnit(units_abbr);
             }
-            if (margin_units == NULL) {
-                margin_units = &px;
+            if (!margin_units) {
+                margin_units = px;
             }
-            margin_top = nv->getMarginLength("fit-margin-top",margin_units, &px, w, h, false);
-            margin_left = nv->getMarginLength("fit-margin-left",margin_units, &px, w, h, true);
-            margin_right = nv->getMarginLength("fit-margin-right",margin_units, &px, w, h, true);
-            margin_bottom = nv->getMarginLength("fit-margin-bottom",margin_units, &px, w, h, false);
+            margin_top = nv->getMarginLength("fit-margin-top",margin_units, px, w, h, false);
+            margin_left = nv->getMarginLength("fit-margin-left",margin_units, px, w, h, true);
+            margin_right = nv->getMarginLength("fit-margin-right",margin_units, px, w, h, true);
+            margin_bottom = nv->getMarginLength("fit-margin-bottom",margin_units, px, w, h, false);
         }
     }
     
@@ -693,8 +692,8 @@ void SPDocument::fitToRect(Geom::Rect const &rect, bool with_margins)
             rect.max() + Geom::Point(margin_right, margin_top));
     
     
-    setWidth(Inkscape::Util::Quantity(rect_with_margins.width(), "px"));
-    setHeight(Inkscape::Util::Quantity(rect_with_margins.height(), "px"));
+    setWidth(Inkscape::Util::Quantity(rect_with_margins.width(), px));
+    setHeight(Inkscape::Util::Quantity(rect_with_margins.height(), px));
 
     Geom::Translate const tr(
             Geom::Point(0, old_height - rect_with_margins.height())
diff --git a/src/extension/internal/emf-inout.cpp b/src/extension/internal/emf-inout.cpp
index 90ab763e0..f1876c687 100644
--- a/src/extension/internal/emf-inout.cpp
+++ b/src/extension/internal/emf-inout.cpp
@@ -3504,7 +3504,7 @@ Emf::open( Inkscape::Extension::Input * /*mod*/, const gchar *uri )
         doc->setViewBox(Geom::Rect::from_xywh(0, 0, doc->getWidth().quantity, doc->getHeight().quantity));
         
         // Scale and translate objects
-        double scale = Inkscape::Util::Quantity::convert(1, "px", doc->getWidth().unit->abbr);
+        double scale = Inkscape::Util::Quantity::convert(1, "px", doc->getWidth().unit);
         ShapeEditor::blockSetItem(true);
         doc->getRoot()->scaleChildItemsRec(Geom::Scale(scale), Geom::Point(0, SP_ACTIVE_DOCUMENT->getHeight().value("px")));
         ShapeEditor::blockSetItem(false);
diff --git a/src/extension/internal/wmf-inout.cpp b/src/extension/internal/wmf-inout.cpp
index aab98dc87..d69d46f20 100644
--- a/src/extension/internal/wmf-inout.cpp
+++ b/src/extension/internal/wmf-inout.cpp
@@ -3192,7 +3192,7 @@ Wmf::open( Inkscape::Extension::Input * /*mod*/, const gchar *uri )
         doc->setViewBox(Geom::Rect::from_xywh(0, 0, doc->getWidth().quantity, doc->getHeight().quantity));
         
         // Scale and translate objects
-        double scale = Inkscape::Util::Quantity::convert(1, "px", doc->getWidth().unit->abbr);
+        double scale = Inkscape::Util::Quantity::convert(1, "px", doc->getWidth().unit);
         ShapeEditor::blockSetItem(true);
         doc->getRoot()->scaleChildItemsRec(Geom::Scale(scale), Geom::Point(0, SP_ACTIVE_DOCUMENT->getHeight().value("px")));
         ShapeEditor::blockSetItem(false);
diff --git a/src/live_effects/parameter/unit.cpp b/src/live_effects/parameter/unit.cpp
index 561766920..0ee553e2c 100644
--- a/src/live_effects/parameter/unit.cpp
+++ b/src/live_effects/parameter/unit.cpp
@@ -24,7 +24,7 @@ UnitParam::UnitParam( const Glib::ustring& label, const Glib::ustring& tip,
                               Effect* effect, Glib::ustring default_unit)
     : Parameter(label, tip, key, wr, effect)
 {
-    defunit = new Inkscape::Util::Unit(unit_table.getUnit(default_unit));
+    defunit = unit_table.getUnit(default_unit);
     unit = defunit;
 }
 
@@ -36,7 +36,7 @@ bool
 UnitParam::param_readSVGValue(const gchar * strvalue)
 {
     if (strvalue) {
-        param_set_value(unit_table.getUnit(strvalue));
+        param_set_value(*unit_table.getUnit(strvalue));
         return true;
     }
     return false;
diff --git a/src/lpe-tool-context.cpp b/src/lpe-tool-context.cpp
index 0b71a892c..bf912746e 100644
--- a/src/lpe-tool-context.cpp
+++ b/src/lpe-tool-context.cpp
@@ -415,7 +415,7 @@ lpetool_create_measuring_items(SPLPEToolContext *lc, Inkscape::Selection *select
             if (!show)
                 sp_canvas_item_hide(SP_CANVAS_ITEM(canvas_text));
 
-            Inkscape::Util::Unit unit;
+            Inkscape::Util::Unit const * unit = NULL;
             if (prefs->getString("/tools/lpetool/unit").compare("")) {
                 unit = unit_table.getUnit(prefs->getString("/tools/lpetool/unit"));
             } else {
@@ -424,7 +424,7 @@ lpetool_create_measuring_items(SPLPEToolContext *lc, Inkscape::Selection *select
 
             lengthval = Geom::length(pwd2);
             lengthval = Inkscape::Util::Quantity::convert(lengthval, "px", unit);
-            arc_length = g_strdup_printf("%.2f %s", lengthval, unit.abbr.c_str());
+            arc_length = g_strdup_printf("%.2f %s", lengthval, unit->abbr.c_str());
             sp_canvastext_set_text (canvas_text, arc_length);
             set_pos_and_anchor(canvas_text, pwd2, 0.5, 10);
             // TODO: must we free arc_length?
@@ -454,7 +454,7 @@ lpetool_update_measuring_items(SPLPEToolContext *lc)
         SPPath *path = i->first;
         SPCurve *curve = path->getCurve();
         Geom::Piecewise<Geom::D2<Geom::SBasis> > pwd2 = Geom::paths_to_pw(curve->get_pathvector());
-        Inkscape::Util::Unit unit;
+        Inkscape::Util::Unit const * unit = NULL;
         if (prefs->getString("/tools/lpetool/unit").compare("")) {
             unit = unit_table.getUnit(prefs->getString("/tools/lpetool/unit"));
         } else {
@@ -462,7 +462,7 @@ lpetool_update_measuring_items(SPLPEToolContext *lc)
         }
         double lengthval = Geom::length(pwd2);
         lengthval = Inkscape::Util::Quantity::convert(lengthval, "px", unit);
-        gchar *arc_length = g_strdup_printf("%.2f %s", lengthval, unit.abbr.c_str());
+        gchar *arc_length = g_strdup_printf("%.2f %s", lengthval, unit->abbr.c_str());
         sp_canvastext_set_text (SP_CANVASTEXT(i->second), arc_length);
         set_pos_and_anchor(SP_CANVASTEXT(i->second), pwd2, 0.5, 10);
         // TODO: must we free arc_length?
diff --git a/src/pen-context.cpp b/src/pen-context.cpp
index d67bc5e57..428ebd6d9 100644
--- a/src/pen-context.cpp
+++ b/src/pen-context.cpp
@@ -1137,7 +1137,7 @@ static void spdc_pen_set_angle_distance_status_message(SPPenContext *const pc, G
     SPDesktop *desktop = SP_EVENT_CONTEXT(pc)->desktop;
     Geom::Point rel = p - pc->p[pc_point_to_compare];
     Inkscape::Util::Quantity q = Inkscape::Util::Quantity(Geom::L2(rel), "px");
-    GString *dist = g_string_new(q.string(*desktop->namedview->doc_units).c_str());
+    GString *dist = g_string_new(q.string(desktop->namedview->doc_units).c_str());
     double angle = atan2(rel[Geom::Y], rel[Geom::X]) * 180 / M_PI;
     Inkscape::Preferences *prefs = Inkscape::Preferences::get();
     if (prefs->getBool("/options/compassangledisplay/value", 0) != 0) {
diff --git a/src/preferences.cpp b/src/preferences.cpp
index 0dc6f1ec4..0dcebbb90 100644
--- a/src/preferences.cpp
+++ b/src/preferences.cpp
@@ -785,9 +785,8 @@ double Preferences::_extractDouble(Entry const &v, Glib::ustring const &requeste
     if (unit.length() == 0) {
         // no unit specified, don't do conversion
         return val;
-    } else {
-        return val * (unit_table.getUnit(unit).factor / unit_table.getUnit(requested_unit).factor);
     }
+    return val * (unit_table.getUnit(unit)->factor / unit_table.getUnit(requested_unit)->factor); /// \todo rewrite using Quantity class, so the standard code handles unit conversion
 }
 
 Glib::ustring Preferences::_extractString(Entry const &v)
diff --git a/src/rect-context.cpp b/src/rect-context.cpp
index f60b3d465..a0e751359 100644
--- a/src/rect-context.cpp
+++ b/src/rect-context.cpp
@@ -426,8 +426,8 @@ void SPRectContext::drag(Geom::Point const pt, guint state) {
 
     Inkscape::Util::Quantity rdimx_q = Inkscape::Util::Quantity(rdimx, "px");
     Inkscape::Util::Quantity rdimy_q = Inkscape::Util::Quantity(rdimy, "px");
-    GString *xs = g_string_new(rdimx_q.string(*desktop->namedview->doc_units).c_str());
-    GString *ys = g_string_new(rdimy_q.string(*desktop->namedview->doc_units).c_str());
+    GString *xs = g_string_new(rdimx_q.string(desktop->namedview->doc_units).c_str());
+    GString *ys = g_string_new(rdimy_q.string(desktop->namedview->doc_units).c_str());
 
     if (state & GDK_CONTROL_MASK) {
         int ratio_x, ratio_y;
diff --git a/src/seltrans.cpp b/src/seltrans.cpp
index f614853bc..7a8f5ec17 100644
--- a/src/seltrans.cpp
+++ b/src/seltrans.cpp
@@ -1274,8 +1274,8 @@ gboolean Inkscape::SelTrans::centerRequest(Geom::Point &pt, guint state)
     // status text
     Inkscape::Util::Quantity x_q = Inkscape::Util::Quantity(pt[Geom::X], "px");
     Inkscape::Util::Quantity y_q = Inkscape::Util::Quantity(pt[Geom::Y], "px");
-    GString *xs = g_string_new(x_q.string(*_desktop->namedview->doc_units).c_str());
-    GString *ys = g_string_new(y_q.string(*_desktop->namedview->doc_units).c_str());
+    GString *xs = g_string_new(x_q.string(_desktop->namedview->doc_units).c_str());
+    GString *ys = g_string_new(y_q.string(_desktop->namedview->doc_units).c_str());
     _message_context.setF(Inkscape::NORMAL_MESSAGE, _("Move <b>center</b> to %s, %s"), xs->str, ys->str);
     g_string_free(xs, FALSE);
     g_string_free(ys, FALSE);
@@ -1428,8 +1428,8 @@ void Inkscape::SelTrans::moveTo(Geom::Point const &xy, guint state)
     // status text
     Inkscape::Util::Quantity x_q = Inkscape::Util::Quantity(dxy[Geom::X], "px");
     Inkscape::Util::Quantity y_q = Inkscape::Util::Quantity(dxy[Geom::Y], "px");
-    GString *xs = g_string_new(x_q.string(*_desktop->namedview->doc_units).c_str());
-    GString *ys = g_string_new(y_q.string(*_desktop->namedview->doc_units).c_str());
+    GString *xs = g_string_new(x_q.string(_desktop->namedview->doc_units).c_str());
+    GString *ys = g_string_new(y_q.string(_desktop->namedview->doc_units).c_str());
     _message_context.setF(Inkscape::NORMAL_MESSAGE, _("<b>Move</b> by %s, %s; with <b>Ctrl</b> to restrict to horizontal/vertical; with <b>Shift</b> to disable snapping"), xs->str, ys->str);
     g_string_free(xs, TRUE);
     g_string_free(ys, TRUE);
diff --git a/src/sp-guide.cpp b/src/sp-guide.cpp
index 83d2d8e78..a0aa9692e 100644
--- a/src/sp-guide.cpp
+++ b/src/sp-guide.cpp
@@ -476,8 +476,8 @@ char *sp_guide_description(SPGuide const *guide, const bool verbose)
 
         Inkscape::Util::Quantity x_q = Inkscape::Util::Quantity(guide->point_on_line[X], "px");
         Inkscape::Util::Quantity y_q = Inkscape::Util::Quantity(guide->point_on_line[Y], "px");
-        GString *position_string_x = g_string_new(x_q.string(*namedview->doc_units).c_str());
-        GString *position_string_y = g_string_new(y_q.string(*namedview->doc_units).c_str());
+        GString *position_string_x = g_string_new(x_q.string(namedview->doc_units).c_str());
+        GString *position_string_y = g_string_new(y_q.string(namedview->doc_units).c_str());
 
         gchar *shortcuts = g_strdup_printf("; %s", _("<b>Shift+drag</b> to rotate, <b>Ctrl+drag</b> to move origin, <b>Del</b> to delete"));
 
diff --git a/src/sp-namedview.cpp b/src/sp-namedview.cpp
index 4464a0be2..ad497ff2f 100644
--- a/src/sp-namedview.cpp
+++ b/src/sp-namedview.cpp
@@ -557,12 +557,11 @@ void SPNamedView::set(unsigned int key, const gchar* value) {
              * in that they aren't in general absolute units as currently required by
              * doc_units.
              */
-            static Inkscape::Util::Unit px = unit_table.getUnit("px");
-            Inkscape::Util::Unit const *new_unit = new Inkscape::Util::Unit(px);
+            static Inkscape::Util::Unit const *px = unit_table.getUnit("px");
+            Inkscape::Util::Unit const *new_unit = px;
 
             if (value) {
-                Inkscape::Util::Unit u = unit_table.getUnit(value);
-                Inkscape::Util::Unit const *const req_unit = new Inkscape::Util::Unit(u);
+                Inkscape::Util::Unit const *const req_unit = unit_table.getUnit(value);
                 if ( !unit_table.hasUnit(value) ) {
                     g_warning("Unrecognized unit `%s'", value);
                     /* fixme: Document errors should be reported in the status bar or
@@ -585,8 +584,7 @@ void SPNamedView::set(unsigned int key, const gchar* value) {
             Inkscape::Util::Unit const *new_unit = NULL;
 
             if (value) {
-                Inkscape::Util::Unit u = unit_table.getUnit(value);
-                Inkscape::Util::Unit const *const req_unit = new Inkscape::Util::Unit(u);
+                Inkscape::Util::Unit const *const req_unit = unit_table.getUnit(value);
                 if ( !unit_table.hasUnit(value) ) {
                     g_warning("Unrecognized unit `%s'", value);
                     /* fixme: Document errors should be reported in the status bar or
@@ -1114,14 +1112,14 @@ double SPNamedView::getMarginLength(gchar const * const key,
                              bool const use_width)
 {
     double value;
-    Inkscape::Util::Unit percent = unit_table.getUnit("%");
+    static Inkscape::Util::Unit const *percent = unit_table.getUnit("%");
     if(!this->storeAsDouble(key,&value)) {
         return 0.0;
     }
-    if (*margin_units == percent) {
+    if (*margin_units == *percent) {
         return (use_width)? width * value : height * value; 
     }
-    if (!margin_units->compatibleWith(*return_units)) {
+    if (!margin_units->compatibleWith(return_units)) {
         return 0.0;
     }
     return value;
@@ -1129,14 +1127,11 @@ double SPNamedView::getMarginLength(gchar const * const key,
 
 /**
  * Returns namedview's default unit.
+ * If no default unit is set, "pt" is returned
  */
-Inkscape::Util::Unit const SPNamedView::getDefaultUnit() const
+Inkscape::Util::Unit const * SPNamedView::getDefaultUnit() const
 {
-    if (doc_units) {
-        return *doc_units;
-    } else {
-        return *(new Inkscape::Util::Unit(unit_table.getUnit("pt")));
-    }
+    return doc_units ? doc_units : unit_table.getUnit("pt");
 }
 
 /**
diff --git a/src/sp-namedview.h b/src/sp-namedview.h
index 30f962d9f..00302e9a1 100644
--- a/src/sp-namedview.h
+++ b/src/sp-namedview.h
@@ -82,7 +82,7 @@ public:
     gchar const *getName() const;
     guint getViewCount();
     GSList const *getViewList() const;
-    Inkscape::Util::Unit const getDefaultUnit() const;
+    Inkscape::Util::Unit const * getDefaultUnit() const;
 
     void translateGuides(Geom::Translate const &translation);
     void translateGrids(Geom::Translate const &translation);
diff --git a/src/sp-text.cpp b/src/sp-text.cpp
index c431f52da..de5e63fe6 100644
--- a/src/sp-text.cpp
+++ b/src/sp-text.cpp
@@ -348,7 +348,7 @@ gchar* SPText::description() {
     }
 
     Inkscape::Util::Quantity q = Inkscape::Util::Quantity(style->font_size.computed, "px");
-    GString *xs = g_string_new(q.string(*sp_desktop_namedview(SP_ACTIVE_DESKTOP)->doc_units).c_str());
+    GString *xs = g_string_new(q.string(sp_desktop_namedview(SP_ACTIVE_DESKTOP)->doc_units).c_str());
 
     char const *trunc = "";
     Inkscape::Text::Layout const *layout = te_get_layout((SPItem *) this);
diff --git a/src/spiral-context.cpp b/src/spiral-context.cpp
index 24a3ea6de..9d44b5adb 100644
--- a/src/spiral-context.cpp
+++ b/src/spiral-context.cpp
@@ -399,7 +399,7 @@ void SPSpiralContext::drag(Geom::Point const &p, guint state) {
 
     /* status text */
     Inkscape::Util::Quantity q = Inkscape::Util::Quantity(rad, "px");
-    GString *rads = g_string_new(q.string(*desktop->namedview->doc_units).c_str());
+    GString *rads = g_string_new(q.string(desktop->namedview->doc_units).c_str());
     this->message_context->setF(Inkscape::IMMEDIATE_MESSAGE,
                                _("<b>Spiral</b>: radius %s, angle %5g&#176;; with <b>Ctrl</b> to snap angle"),
                                rads->str, sp_round((arg + 2.0*M_PI*this->spiral->revo)*180/M_PI, 0.0001));
diff --git a/src/star-context.cpp b/src/star-context.cpp
index 30112cbe9..d801ad0a0 100644
--- a/src/star-context.cpp
+++ b/src/star-context.cpp
@@ -417,7 +417,7 @@ void SPStarContext::drag(Geom::Point p, guint state)
 
     /* status text */
     Inkscape::Util::Quantity q = Inkscape::Util::Quantity(r1, "px");
-    GString *rads = g_string_new(q.string(*desktop->namedview->doc_units).c_str());
+    GString *rads = g_string_new(q.string(desktop->namedview->doc_units).c_str());
     this->message_context->setF(Inkscape::IMMEDIATE_MESSAGE,
                                ( this->isflatsided?
                                  _("<b>Polygon</b>: radius %s, angle %5g&#176;; with <b>Ctrl</b> to snap angle")
diff --git a/src/text-context.cpp b/src/text-context.cpp
index f12ce6aa6..7d9b9848f 100644
--- a/src/text-context.cpp
+++ b/src/text-context.cpp
@@ -601,8 +601,8 @@ bool SPTextContext::root_handler(GdkEvent* event) {
                 // status text
                 Inkscape::Util::Quantity x_q = Inkscape::Util::Quantity(fabs((p - this->p0)[Geom::X]), "px");
                 Inkscape::Util::Quantity y_q = Inkscape::Util::Quantity(fabs((p - this->p0)[Geom::Y]), "px");
-                GString *xs = g_string_new(x_q.string(*desktop->namedview->doc_units).c_str());
-                GString *ys = g_string_new(y_q.string(*desktop->namedview->doc_units).c_str());
+                GString *xs = g_string_new(x_q.string(desktop->namedview->doc_units).c_str());
+                GString *ys = g_string_new(y_q.string(desktop->namedview->doc_units).c_str());
                 this->message_context->setF(Inkscape::IMMEDIATE_MESSAGE, _("<b>Flowed text frame</b>: %s &#215; %s"), xs->str, ys->str);
 
                 g_string_free(xs, FALSE);
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;
diff --git a/src/util/expression-evaluator.cpp b/src/util/expression-evaluator.cpp
index 3b7e77c6c..48064e647 100644
--- a/src/util/expression-evaluator.cpp
+++ b/src/util/expression-evaluator.cpp
@@ -48,7 +48,7 @@ EvaluatorToken::EvaluatorToken()
     value.fl = 0;
 }
 
-ExpressionEvaluator::ExpressionEvaluator(const char *string, Unit *unit) :
+ExpressionEvaluator::ExpressionEvaluator(const char *string, Unit const *unit) :
     string(string),
     unit(unit)
 {
@@ -360,7 +360,7 @@ int ExpressionEvaluator::getIdentifierSize(const char *string, int start_offset)
 
 bool ExpressionEvaluator::resolveUnit (const char* identifier,
                                        EvaluatorQuantity *result,
-                                       Unit* unit)
+                                       Unit const* unit)
 {
     if (!unit) {
         result->value = 1;
@@ -371,9 +371,9 @@ bool ExpressionEvaluator::resolveUnit (const char* identifier,
         result->dimension = unit->isAbsolute() ? 1 : 0;
         return true;
     } else if (unit_table.hasUnit(identifier)) {
-        Unit identifier_unit = unit_table.getUnit(identifier);
-        result->value = Quantity::convert(1, *unit, identifier_unit);
-        result->dimension = identifier_unit.isAbsolute() ? 1 : 0;
+        Unit const *identifier_unit = unit_table.getUnit(identifier);
+        result->value = Quantity::convert(1, unit, identifier_unit);
+        result->dimension = identifier_unit->isAbsolute() ? 1 : 0;
         return true;
     } else {
         return false;
diff --git a/src/util/expression-evaluator.h b/src/util/expression-evaluator.h
index 6412dfea7..50ff3fb70 100644
--- a/src/util/expression-evaluator.h
+++ b/src/util/expression-evaluator.h
@@ -133,13 +133,13 @@ public:
 class ExpressionEvaluator
 {
 public:
-    ExpressionEvaluator(const char *string, Unit *unit = NULL);
+    ExpressionEvaluator(const char *string, Unit const *unit = NULL);
     
     EvaluatorQuantity evaluate();
 
 private:
     const char *string;
-    Unit *unit;
+    Unit const *unit;
     
     EvaluatorToken current_token;
     const char *start_of_current_token;
@@ -160,7 +160,7 @@ private:
     static bool isUnitIdentifierStart(gunichar c);
     static int getIdentifierSize(const char *s, int start);
     
-    static bool resolveUnit(const char *identifier, EvaluatorQuantity *result, Unit *unit);
+    static bool resolveUnit(const char *identifier, EvaluatorQuantity *result, Unit const *unit);
     
     void throwError(const char *msg);
 };
diff --git a/src/util/units.cpp b/src/util/units.cpp
index cabbc044d..1023cfb6e 100644
--- a/src/util/units.cpp
+++ b/src/util/units.cpp
@@ -189,15 +189,15 @@ int Unit::defaultDigits() const
     return factor_digits;
 }
 
-bool Unit::compatibleWith(Unit const &u) const
+bool Unit::compatibleWith(Unit const *u) const
 {
     // Percentages
-    if (type == UNIT_TYPE_DIMENSIONLESS || u.type == UNIT_TYPE_DIMENSIONLESS) {
+    if (type == UNIT_TYPE_DIMENSIONLESS || u->type == UNIT_TYPE_DIMENSIONLESS) {
         return true;
     }
 
     // Other units with same type
-    if (type == u.type) {
+    if (type == u->type) {
         return true;
     }
 
@@ -254,30 +254,30 @@ void UnitTable::addUnit(Unit const &u, bool primary)
     }
 }
 
-Unit const &UnitTable::getUnit(char const *abbr) const
+Unit const *UnitTable::getUnit(char const *abbr) const
 {
     UnitCodeMap::const_iterator f = _unit_map.find(make_unit_code(abbr));
     if (f != _unit_map.end()) {
-        return *f->second;
+        return &(*f->second);
     }
-    return _empty_unit;
+    return &_empty_unit;
 }
 
-Unit const &UnitTable::getUnit(Glib::ustring const &unit_abbr) const
+Unit const *UnitTable::getUnit(Glib::ustring const &unit_abbr) const
 {
     return getUnit(unit_abbr.c_str());
 }
-Unit const &UnitTable::getUnit(SVGLength::Unit u) const
+Unit const *UnitTable::getUnit(SVGLength::Unit u) const
 {
     if (u == 0 || u > SVGLength::LAST_UNIT) {
-        return _empty_unit;
+        return &_empty_unit;
     }
 
     UnitCodeMap::const_iterator f = _unit_map.find(svg_length_lookup[u]);
     if (f != _unit_map.end()) {
-        return *f->second;
+        return &(*f->second);
     }
-    return _empty_unit;
+    return &_empty_unit;
 }
 
 Quantity UnitTable::parseQuantity(Glib::ustring const &q) const
@@ -303,6 +303,7 @@ Quantity UnitTable::parseQuantity(Glib::ustring const &q) const
     return qty;
 }
 
+/* UNSAFE while passing around pointers to the Unit objects in this table 
 bool UnitTable::deleteUnit(Unit const &u)
 {
     bool deleted = false;
@@ -318,6 +319,7 @@ bool UnitTable::deleteUnit(Unit const &u)
     }
     return deleted;
 }
+*/
 
 bool UnitTable::hasUnit(Glib::ustring const &unit) const
 {
@@ -418,23 +420,23 @@ void UnitParser::on_end_element(Ctx &ctx, Glib::ustring const &name)
     }
 }
 
-Quantity::Quantity(double q, Unit const &u)
+Quantity::Quantity(double q, Unit const *u)
+  : unit(u)
+  , quantity(q)
 {
-    unit = new Unit(u);
-    quantity = q;
 }
 Quantity::Quantity(double q, Glib::ustring const &u)
+  : unit(unit_table.getUnit(u.c_str()))
+  , quantity(q)
 {
-    unit = new Unit(unit_table.getUnit(u.c_str()));
-    quantity = q;
 }
 Quantity::Quantity(double q, char const *u)
+  : unit(unit_table.getUnit(u))
+  , quantity(q)
 {
-    unit = new Unit(unit_table.getUnit(u));
-    quantity = q;
 }
 
-bool Quantity::compatibleWith(Unit const &u) const
+bool Quantity::compatibleWith(Unit const *u) const
 {
     return unit->compatibleWith(u);
 }
@@ -447,9 +449,9 @@ bool Quantity::compatibleWith(char const *u) const
     return compatibleWith(unit_table.getUnit(u));
 }
 
-double Quantity::value(Unit const &u) const
+double Quantity::value(Unit const *u) const
 {
-    return convert(quantity, *unit, u);
+    return convert(quantity, unit, u);
 }
 double Quantity::value(Glib::ustring const &u) const
 {
@@ -460,36 +462,36 @@ double Quantity::value(char const *u) const
     return value(unit_table.getUnit(u));
 }
 
-Glib::ustring Quantity::string(Unit const &u) const {
+Glib::ustring Quantity::string(Unit const *u) const {
     return Glib::ustring::format(std::fixed, std::setprecision(2), value(u)) + " " + unit->abbr;
 }
 Glib::ustring Quantity::string(Glib::ustring const &u) const {
     return string(unit_table.getUnit(u.c_str()));
 }
 Glib::ustring Quantity::string() const {
-    return string(*unit);
+    return string(unit);
 }
 
-double Quantity::convert(double from_dist, Unit const &from, Unit const &to)
+double Quantity::convert(double from_dist, Unit const *from, Unit const *to)
 {
     // Percentage
-    if (to.type == UNIT_TYPE_DIMENSIONLESS) {
-        return from_dist * to.factor;
+    if (to->type == UNIT_TYPE_DIMENSIONLESS) {
+        return from_dist * to->factor;
     }
     
     // Incompatible units
-    if (from.type != to.type) {
+    if (from->type != to->type) {
         return -1;
     }
     
     // Compatible units
-    return from_dist * from.factor / to.factor;
+    return from_dist * from->factor / to->factor;
 }
-double Quantity::convert(double from_dist, Glib::ustring const &from, Unit const &to)
+double Quantity::convert(double from_dist, Glib::ustring const &from, Unit const *to)
 {
     return convert(from_dist, unit_table.getUnit(from.c_str()), to);
 }
-double Quantity::convert(double from_dist, Unit const &from, Glib::ustring const &to)
+double Quantity::convert(double from_dist, Unit const *from, Glib::ustring const &to)
 {
     return convert(from_dist, from, unit_table.getUnit(to.c_str()));
 }
@@ -508,7 +510,7 @@ bool Quantity::operator<(Quantity const &other) const
         g_warning("Incompatible units");
         return false;
     }
-    return quantity < other.value(*unit);
+    return quantity < other.value(unit);
 }
 bool Quantity::operator==(Quantity const &other) const
 {
diff --git a/src/util/units.h b/src/util/units.h
index 7566715d8..e1addaa24 100644
--- a/src/util/units.h
+++ b/src/util/units.h
@@ -58,7 +58,7 @@ public:
     int            defaultDigits() const;
 
     /** Checks if a unit is compatible with the specified unit. */
-    bool           compatibleWith(Unit const &u) const;
+    bool           compatibleWith(Unit const *u) const;
     bool           compatibleWith(Glib::ustring const &) const;
     bool           compatibleWith(char const *) const;
 
@@ -84,29 +84,30 @@ public:
     double quantity;
     
     /** Initialize a quantity. */
-    Quantity(double q, Unit const &u);
+    Quantity(double q, Unit const *u);
     Quantity(double q, Glib::ustring const &u);
     Quantity(double q, char const *u);
     
     /** Checks if a quantity is compatible with the specified unit. */
-    bool compatibleWith(Unit const &u) const;
+    bool compatibleWith(Unit const *u) const;
     bool compatibleWith(Glib::ustring const &u) const;
     bool compatibleWith(char const *u) const;
     
     /** Return the quantity's value in the specified unit. */
-    double value(Unit const &u) const;
+    double value(Unit const *u) const;
     double value(Glib::ustring const &u) const;
     double value(char const *u) const;
     
     /** Return a printable string of the value in the specified unit. */
-    Glib::ustring string(Unit const &u) const;
+    Glib::ustring string(Unit const *u) const;
     Glib::ustring string(Glib::ustring const &u) const;
     Glib::ustring string() const;
     
-    /** Convert distances. */
-    static double convert(double from_dist, Unit const &from, Unit const &to);
-    static double convert(double from_dist, Glib::ustring const &from, Unit const &to);
-    static double convert(double from_dist, Unit const &from, Glib::ustring const &to);
+    /** Convert distances. 
+       no NULL check is performed on the passed pointers to Unit objects!  */
+    static double convert(double from_dist, Unit const *from, Unit const *to);
+    static double convert(double from_dist, Glib::ustring const &from, Unit const *to);
+    static double convert(double from_dist, Unit const *from, Glib::ustring const &to);
     static double convert(double from_dist, Glib::ustring const &from, Glib::ustring const &to);
     static double convert(double from_dist, char const *from, char const *to);
 
@@ -132,17 +133,18 @@ public:
     void    addUnit(Unit const &u, bool primary);
 
     /** Retrieve a given unit based on its string identifier */
-    Unit const &getUnit(Glib::ustring const &name) const;
-    Unit const &getUnit(char const *name) const;
+    Unit const *getUnit(Glib::ustring const &name) const;
+    Unit const *getUnit(char const *name) const;
     
     /** Retrieve a given unit based on its SVGLength unit */
-    Unit const &getUnit(SVGLength::Unit u) const;
+    Unit const *getUnit(SVGLength::Unit u) const;
     
     /** Retrieve a quantity based on its string identifier */
     Quantity parseQuantity(Glib::ustring const &q) const;
 
-    /** Remove a unit definition from the given unit type table */
-    bool    deleteUnit(Unit const &u);
+    /** Remove a unit definition from the given unit type table * /
+     * DISABLED, unsafe with the current passing around pointers to Unit objects in this table */
+    //bool    deleteUnit(Unit const &u);
 
     /** Returns true if the given string 'name' is a valid unit in the table */
     bool    hasUnit(Glib::ustring const &name) const;
diff --git a/src/widgets/desktop-widget.cpp b/src/widgets/desktop-widget.cpp
index e9a834db7..3ca433586 100644
--- a/src/widgets/desktop-widget.cpp
+++ b/src/widgets/desktop-widget.cpp
@@ -394,9 +394,9 @@ void SPDesktopWidget::init( SPDesktopWidget *dtw )
     GtkWidget *eventbox = gtk_event_box_new ();
     dtw->hruler = sp_ruler_new(GTK_ORIENTATION_HORIZONTAL);
     dtw->hruler_box = eventbox;
-    Inkscape::Util::Unit pt = unit_table.getUnit("pt");
+    Inkscape::Util::Unit const *pt = unit_table.getUnit("pt");
     sp_ruler_set_unit(SP_RULER(dtw->hruler), pt);
-    gtk_widget_set_tooltip_text (dtw->hruler_box, gettext(pt.name_plural.c_str()));
+    gtk_widget_set_tooltip_text (dtw->hruler_box, gettext(pt->name_plural.c_str()));
     gtk_container_add (GTK_CONTAINER (eventbox), dtw->hruler);
     g_signal_connect (G_OBJECT (eventbox), "button_press_event", G_CALLBACK (sp_dt_hruler_event), dtw);
     g_signal_connect (G_OBJECT (eventbox), "button_release_event", G_CALLBACK (sp_dt_hruler_event), dtw);
@@ -425,7 +425,7 @@ void SPDesktopWidget::init( SPDesktopWidget *dtw )
     dtw->vruler = sp_ruler_new(GTK_ORIENTATION_VERTICAL);
     dtw->vruler_box = eventbox;
     sp_ruler_set_unit (SP_RULER (dtw->vruler), pt);
-    gtk_widget_set_tooltip_text (dtw->vruler_box, gettext(pt.name_plural.c_str()));
+    gtk_widget_set_tooltip_text (dtw->vruler_box, gettext(pt->name_plural.c_str()));
     gtk_container_add (GTK_CONTAINER (eventbox), GTK_WIDGET (dtw->vruler));
 
 #if GTK_CHECK_VERSION(3,0,0)
diff --git a/src/widgets/lpe-toolbar.cpp b/src/widgets/lpe-toolbar.cpp
index 922526a9f..045d7aa78 100644
--- a/src/widgets/lpe-toolbar.cpp
+++ b/src/widgets/lpe-toolbar.cpp
@@ -198,9 +198,9 @@ static void lpetool_toggle_show_measuring_info(GtkToggleAction *act, GObject *tb
 static void lpetool_unit_changed(GtkAction* /*act*/, GObject* tbl)
 {
     UnitTracker* tracker = reinterpret_cast<UnitTracker*>(g_object_get_data(tbl, "tracker"));
-    Unit const unit = tracker->getActiveUnit();
+    Unit const *unit = tracker->getActiveUnit();
     Inkscape::Preferences *prefs = Inkscape::Preferences::get();
-    prefs->setString("/tools/lpetool/unit", unit.abbr);
+    prefs->setString("/tools/lpetool/unit", unit->abbr);
 
     SPDesktop *desktop = static_cast<SPDesktop *>(g_object_get_data( tbl, "desktop" ));
     if (SP_IS_LPETOOL_CONTEXT(desktop->event_context)) {
@@ -299,10 +299,10 @@ void sp_lpetool_toolbox_prep(SPDesktop *desktop, GtkActionGroup* mainActions, GO
     UnitTracker* tracker = new UnitTracker(Inkscape::Util::UNIT_TYPE_LINEAR);
     tracker->setActiveUnit(sp_desktop_namedview(desktop)->doc_units);
     g_object_set_data(holder, "tracker", tracker);
-    Unit const unit = tracker->getActiveUnit();
+    Unit const *unit = tracker->getActiveUnit();
 
     Inkscape::Preferences *prefs = Inkscape::Preferences::get();
-    prefs->setString("/tools/lpetool/unit", unit.abbr);
+    prefs->setString("/tools/lpetool/unit", unit->abbr);
 
     /** Automatically create a list of LPEs that get added to the toolbar **/
     {
diff --git a/src/widgets/measure-toolbar.cpp b/src/widgets/measure-toolbar.cpp
index 53ed2d275..58244566d 100644
--- a/src/widgets/measure-toolbar.cpp
+++ b/src/widgets/measure-toolbar.cpp
@@ -82,7 +82,7 @@ sp_measure_fontsize_value_changed(GtkAdjustment *adj, GObject *tbl)
 static void measure_unit_changed(GtkAction* /*act*/, GObject* tbl)
 {
     UnitTracker* tracker = reinterpret_cast<UnitTracker*>(g_object_get_data(tbl, "tracker"));
-    Glib::ustring const unit = tracker->getActiveUnit().abbr;
+    Glib::ustring const unit = tracker->getActiveUnit()->abbr;
     Inkscape::Preferences *prefs = Inkscape::Preferences::get();
     prefs->setString("/tools/measure/unit", unit);
 }
diff --git a/src/widgets/node-toolbar.cpp b/src/widgets/node-toolbar.cpp
index 2348acc46..0d4868642 100644
--- a/src/widgets/node-toolbar.cpp
+++ b/src/widgets/node-toolbar.cpp
@@ -240,7 +240,7 @@ static void sp_node_toolbox_coord_changed(gpointer /*shape_editor*/, GObject *tb
     if (!tracker) {
         return;
     }
-    Unit const unit = tracker->getActiveUnit();
+    Unit const *unit = tracker->getActiveUnit();
 
     InkNodeTool *nt = get_node_tool();
     if (!nt || nt->_selected_nodes->empty()) {
@@ -274,7 +274,7 @@ static void sp_node_path_value_changed(GtkAdjustment *adj, GObject *tbl, Geom::D
     if (!tracker) {
         return;
     }
-    Unit const unit = tracker->getActiveUnit();
+    Unit const *unit = tracker->getActiveUnit();
 
     if (DocumentUndo::getUndoSensitive(sp_desktop_document(desktop))) {
         prefs->setDouble(Glib::ustring("/tools/nodes/") + (d == Geom::X ? "x" : "y"),
diff --git a/src/widgets/paintbucket-toolbar.cpp b/src/widgets/paintbucket-toolbar.cpp
index 028753b59..363fadd3d 100644
--- a/src/widgets/paintbucket-toolbar.cpp
+++ b/src/widgets/paintbucket-toolbar.cpp
@@ -98,13 +98,13 @@ static void paintbucket_autogap_changed(EgeSelectOneAction* act, GObject * /*tbl
 static void paintbucket_offset_changed(GtkAdjustment *adj, GObject *tbl)
 {
     UnitTracker* tracker = static_cast<UnitTracker*>(g_object_get_data( tbl, "tracker" ));
-    Unit const unit = tracker->getActiveUnit();
+    Unit const *unit = tracker->getActiveUnit();
     Inkscape::Preferences *prefs = Inkscape::Preferences::get();
 
     // Don't adjust the offset value because we're saving the
     // unit and it'll be correctly handled on load.
     prefs->setDouble("/tools/paintbucket/offset", (gdouble)gtk_adjustment_get_value(adj));
-    prefs->setString("/tools/paintbucket/offsetunits", unit.abbr);
+    prefs->setString("/tools/paintbucket/offsetunits", unit->abbr);
 }
 
 static void paintbucket_defaults(GtkWidget *, GObject *tbl)
@@ -179,8 +179,8 @@ void sp_paintbucket_toolbox_prep(SPDesktop *desktop, GtkActionGroup* mainActions
     UnitTracker* tracker = new UnitTracker(Inkscape::Util::UNIT_TYPE_LINEAR);
     Glib::ustring stored_unit = prefs->getString("/tools/paintbucket/offsetunits");
     if (!stored_unit.empty()) {
-        Unit u = unit_table.getUnit(stored_unit);
-        tracker->setActiveUnit(&u);
+        Unit const *u = unit_table.getUnit(stored_unit);
+        tracker->setActiveUnit(u);
     }
     g_object_set_data( holder, "tracker", tracker );
     {
diff --git a/src/widgets/rect-toolbar.cpp b/src/widgets/rect-toolbar.cpp
index 0d5d3a688..0287a9aeb 100644
--- a/src/widgets/rect-toolbar.cpp
+++ b/src/widgets/rect-toolbar.cpp
@@ -93,7 +93,7 @@ static void sp_rtb_value_changed(GtkAdjustment *adj, GObject *tbl, gchar const *
     SPDesktop *desktop = static_cast<SPDesktop *>(g_object_get_data( tbl, "desktop" ));
 
     UnitTracker* tracker = reinterpret_cast<UnitTracker*>(g_object_get_data( tbl, "tracker" ));
-    Unit const unit = tracker->getActiveUnit();
+    Unit const *unit = tracker->getActiveUnit();
 
     if (DocumentUndo::getUndoSensitive(sp_desktop_document(desktop))) {
         Inkscape::Preferences *prefs = Inkscape::Preferences::get();
@@ -114,7 +114,7 @@ static void sp_rtb_value_changed(GtkAdjustment *adj, GObject *tbl, gchar const *
     for (GSList const *items = selection->itemList(); items != NULL; items = items->next) {
         if (SP_IS_RECT(items->data)) {
             if (gtk_adjustment_get_value(adj) != 0) {
-                (SP_RECT(items->data)->*setter)(Quantity::convert(gtk_adjustment_get_value(adj), unit, *sp_desktop_namedview(desktop)->doc_units));
+                (SP_RECT(items->data)->*setter)(Quantity::convert(gtk_adjustment_get_value(adj), unit, sp_desktop_namedview(desktop)->doc_units));
             } else {
                 SP_OBJECT(items->data)->getRepr()->setAttribute(value_name, NULL);
             }
@@ -185,8 +185,8 @@ static void rect_tb_event_attr_changed(Inkscape::XML::Node * /*repr*/, gchar con
     g_object_set_data( tbl, "freeze", GINT_TO_POINTER(TRUE) );
 
     UnitTracker* tracker = reinterpret_cast<UnitTracker*>( g_object_get_data( tbl, "tracker" ) );
-    Unit const unit = tracker->getActiveUnit();
-    Unit const doc_unit = *sp_desktop_namedview(SP_ACTIVE_DESKTOP)->doc_units;
+    Unit const *unit = tracker->getActiveUnit();
+    Unit const *doc_unit = sp_desktop_namedview(SP_ACTIVE_DESKTOP)->doc_units;
 
     gpointer item = g_object_get_data( tbl, "item" );
     if (item && SP_IS_RECT(item)) {
diff --git a/src/widgets/ruler.cpp b/src/widgets/ruler.cpp
index e4e72d86e..2604ebf22 100644
--- a/src/widgets/ruler.cpp
+++ b/src/widgets/ruler.cpp
@@ -63,7 +63,7 @@ enum {
 typedef struct
 {
   GtkOrientation   orientation;
-  Inkscape::Util::Unit *unit;
+  Inkscape::Util::Unit const *unit;
   gdouble          lower;
   gdouble          upper;
   gdouble          position;
@@ -260,7 +260,7 @@ sp_ruler_init (SPRuler *ruler)
   gtk_widget_set_has_window (GTK_WIDGET (ruler), FALSE);
 
   priv->orientation   = GTK_ORIENTATION_HORIZONTAL;
-  priv->unit          = new Inkscape::Util::Unit(unit_table.getUnit("px"));
+  priv->unit          = unit_table.getUnit("px");
   priv->lower         = 0;
   priv->upper         = 0;
   priv->position      = 0;
@@ -1071,15 +1071,15 @@ sp_ruler_remove_track_widget (SPRuler   *ruler,
  */
 void
 sp_ruler_set_unit (SPRuler  *ruler,
-                   const Inkscape::Util::Unit &unit)
+                   Inkscape::Util::Unit const *unit)
 {
   SPRulerPrivate *priv = SP_RULER_GET_PRIVATE (ruler);
   
   g_return_if_fail (SP_IS_RULER (ruler));
 
-  if (*priv->unit != unit)
+  if (*priv->unit != *unit)
     {
-      priv->unit = new Inkscape::Util::Unit(unit);
+      priv->unit = unit;
       g_object_notify(G_OBJECT(ruler), "unit");
 
       gtk_widget_queue_draw (GTK_WIDGET (ruler));
@@ -1092,7 +1092,7 @@ sp_ruler_set_unit (SPRuler  *ruler,
  *
  * Return value: the unit currently used in the @ruler widget.
  **/
-Inkscape::Util::Unit*
+Inkscape::Util::Unit const*
 sp_ruler_get_unit (SPRuler *ruler)
 {
   return SP_RULER_GET_PRIVATE (ruler)->unit;
@@ -1182,7 +1182,7 @@ sp_ruler_draw_ticks (SPRuler *ruler)
     gint             text_size;
     gint             pos;
     gdouble          max_size;
-    Inkscape::Util::Unit *unit;
+    Inkscape::Util::Unit const *unit = NULL;
     SPRulerMetric    ruler_metric = ruler_metric_general; /* The metric to use for this unit system */
     PangoLayout     *layout;
     PangoRectangle   logical_rect, ink_rect;
@@ -1298,7 +1298,7 @@ sp_ruler_draw_ticks (SPRuler *ruler)
 
     /* Inkscape change to ruler: Use a 1,2,4,8... scale for inches
      * or a 1,2,5,10... scale for everything else */
-    if (*sp_ruler_get_unit (ruler) == unit_table.getUnit("in"))
+    if (*sp_ruler_get_unit (ruler) == *unit_table.getUnit("in"))
       ruler_metric = ruler_metric_inches;
 
     for (scale = 0; scale < G_N_ELEMENTS (ruler_metric.ruler_scale); scale++)
@@ -1317,7 +1317,7 @@ sp_ruler_draw_ticks (SPRuler *ruler)
         gdouble subd_incr;
        
         /* hack to get proper subdivisions at full pixels */
-        if (*unit == unit_table.getUnit("px") && scale == 1 && i == 1)
+        if (*unit == *unit_table.getUnit("px") && scale == 1 && i == 1)
           subd_incr = 1.0;
         else
           subd_incr = ((gdouble) ruler_metric.ruler_scale[scale] / 
diff --git a/src/widgets/ruler.h b/src/widgets/ruler.h
index 08760f584..ed529d082 100644
--- a/src/widgets/ruler.h
+++ b/src/widgets/ruler.h
@@ -56,8 +56,8 @@ void            sp_ruler_remove_track_widget (SPRuler        *ruler,
 		                              GtkWidget      *widget);
 
 void            sp_ruler_set_unit            (SPRuler        *ruler,
-                                              const Inkscape::Util::Unit &unit);
-Inkscape::Util::Unit *sp_ruler_get_unit            (SPRuler        *ruler);
+                                              const Inkscape::Util::Unit *unit);
+Inkscape::Util::Unit const * sp_ruler_get_unit            (SPRuler        *ruler);
 void            sp_ruler_set_position        (SPRuler        *ruler,
                                               gdouble         set_position);
 gdouble         sp_ruler_get_position        (SPRuler        *ruler);
diff --git a/src/widgets/select-toolbar.cpp b/src/widgets/select-toolbar.cpp
index 590b0867f..58d7134b3 100644
--- a/src/widgets/select-toolbar.cpp
+++ b/src/widgets/select-toolbar.cpp
@@ -80,7 +80,7 @@ sp_selection_layout_widget_update(SPWidget *spw, Inkscape::Selection *sel)
         Geom::OptRect const bbox(sel->bounds(bbox_type));
         if ( bbox ) {
             UnitTracker *tracker = reinterpret_cast<UnitTracker*>(g_object_get_data(G_OBJECT(spw), "tracker"));
-            Unit const unit = tracker->getActiveUnit();
+            Unit const *unit = tracker->getActiveUnit();
 
             struct { char const *key; double val; } const keyval[] = {
                 { "X", bbox->min()[X] },
@@ -89,8 +89,8 @@ sp_selection_layout_widget_update(SPWidget *spw, Inkscape::Selection *sel)
                 { "height", bbox->dimensions()[Y] }
             };
 
-            if (unit.type == Inkscape::Util::UNIT_TYPE_DIMENSIONLESS) {
-                double const val = unit.factor * 100;
+            if (unit->type == Inkscape::Util::UNIT_TYPE_DIMENSIONLESS) {
+                double const val = unit->factor * 100;
                 for (unsigned i = 0; i < G_N_ELEMENTS(keyval); ++i) {
                     GtkAdjustment *a = GTK_ADJUSTMENT(g_object_get_data(G_OBJECT(spw), keyval[i].key));
                     gtk_adjustment_set_value(a, val);
@@ -185,14 +185,14 @@ sp_object_layout_any_value_changed(GtkAdjustment *adj, SPWidget *spw)
     gdouble y1 = 0;
     gdouble xrel = 0;
     gdouble yrel = 0;
-    Unit const unit = tracker->getActiveUnit();
+    Unit const *unit = tracker->getActiveUnit();
 
     GtkAdjustment* a_x = GTK_ADJUSTMENT( g_object_get_data( G_OBJECT(spw), "X" ) );
     GtkAdjustment* a_y = GTK_ADJUSTMENT( g_object_get_data( G_OBJECT(spw), "Y" ) );
     GtkAdjustment* a_w = GTK_ADJUSTMENT( g_object_get_data( G_OBJECT(spw), "width" ) );
     GtkAdjustment* a_h = GTK_ADJUSTMENT( g_object_get_data( G_OBJECT(spw), "height" ) );
 
-    if (unit.type == Inkscape::Util::UNIT_TYPE_LINEAR) {
+    if (unit->type == Inkscape::Util::UNIT_TYPE_LINEAR) {
         x0 = Quantity::convert(gtk_adjustment_get_value(a_x), unit, "px");
         y0 = Quantity::convert(gtk_adjustment_get_value(a_y), unit, "px");
         x1 = x0 + Quantity::convert(gtk_adjustment_get_value(a_w), unit, "px");
@@ -200,13 +200,13 @@ sp_object_layout_any_value_changed(GtkAdjustment *adj, SPWidget *spw)
         y1 = y0 + Quantity::convert(gtk_adjustment_get_value(a_h), unit, "px");;
         yrel = Quantity::convert(gtk_adjustment_get_value(a_h), unit, "px") / bbox_user->dimensions()[Geom::Y];
     } else {
-        double const x0_propn = gtk_adjustment_get_value (a_x) / 100 / unit.factor;
+        double const x0_propn = gtk_adjustment_get_value (a_x) / 100 / unit->factor;
         x0 = bbox_user->min()[Geom::X] * x0_propn;
-        double const y0_propn = gtk_adjustment_get_value (a_y) / 100 / unit.factor;
+        double const y0_propn = gtk_adjustment_get_value (a_y) / 100 / unit->factor;
         y0 = y0_propn * bbox_user->min()[Geom::Y];
-        xrel = gtk_adjustment_get_value (a_w) / (100 / unit.factor);
+        xrel = gtk_adjustment_get_value (a_w) / (100 / unit->factor);
         x1 = x0 + xrel * bbox_user->dimensions()[Geom::X];
-        yrel = gtk_adjustment_get_value (a_h) / (100 / unit.factor);
+        yrel = gtk_adjustment_get_value (a_h) / (100 / unit->factor);
         y1 = y0 + yrel * bbox_user->dimensions()[Geom::Y];
     }
 
@@ -227,7 +227,7 @@ sp_object_layout_any_value_changed(GtkAdjustment *adj, SPWidget *spw)
     double sv = fabs(y1 - bbox_user->max()[Geom::Y]);
 
     // unless the unit is %, convert the scales and moves to the unit
-    if (unit.type == Inkscape::Util::UNIT_TYPE_LINEAR) {
+    if (unit->type == Inkscape::Util::UNIT_TYPE_LINEAR) {
         mh = Quantity::convert(mh, "px", unit);
         sh = Quantity::convert(sh, "px", unit);
         mv = Quantity::convert(mv, "px", unit);
diff --git a/src/widgets/stroke-style.cpp b/src/widgets/stroke-style.cpp
index a0b638031..d140cfb21 100644
--- a/src/widgets/stroke-style.cpp
+++ b/src/widgets/stroke-style.cpp
@@ -147,7 +147,8 @@ StrokeStyle::StrokeStyle() :
     selectModifiedConn(),
     startMarkerConn(),
     midMarkerConn(),
-    endMarkerConn()
+    endMarkerConn(),
+    _old_unit(NULL)
 {
     Gtk::HBox *hb;
     Gtk::HBox *f = new Gtk::HBox(false, 0);
@@ -199,12 +200,12 @@ StrokeStyle::StrokeStyle() :
     Gtk::Widget *us = manage(unitSelector);
     SPDesktop *desktop = SP_ACTIVE_DESKTOP;
 
-    unitSelector->addUnit(unit_table.getUnit("%"));
+    unitSelector->addUnit(*unit_table.getUnit("%"));
+    _old_unit = unitSelector->getUnit();
     if (desktop) {
         unitSelector->setUnit(sp_desktop_namedview(desktop)->doc_units->abbr);
-        _old_unit = new Inkscape::Util::Unit(*sp_desktop_namedview(desktop)->doc_units);
+        _old_unit = sp_desktop_namedview(desktop)->doc_units;
     }
-    _old_unit = new Inkscape::Util::Unit(unitSelector->getUnit());
     widthSpin->setUnitMenu(unitSelector);
     unitChangedConn = unitSelector->signal_changed().connect(sigc::mem_fun(*this, &StrokeStyle::unitChangedCB));
     
@@ -529,12 +530,12 @@ void StrokeStyle::updateMarkerHist(SPMarkerLoc const which)
  */
 void StrokeStyle::unitChangedCB()
 {
-    Inkscape::Util::Unit new_unit = unitSelector->getUnit();
-    if (new_unit.type == Inkscape::Util::UNIT_TYPE_DIMENSIONLESS) {
+    Inkscape::Util::Unit const *new_unit = unitSelector->getUnit();
+    if (new_unit->type == Inkscape::Util::UNIT_TYPE_DIMENSIONLESS) {
         widthSpin->set_value(100);
     }
-    widthSpin->set_value(Inkscape::Util::Quantity::convert(widthSpin->get_value(), *_old_unit, new_unit));
-    _old_unit = new Inkscape::Util::Unit(new_unit);
+    widthSpin->set_value(Inkscape::Util::Quantity::convert(widthSpin->get_value(), _old_unit, new_unit));
+    _old_unit = new_unit;
 }
 
 /**
@@ -824,21 +825,20 @@ StrokeStyle::updateLine()
     } else {
         table->set_sensitive(true);
 
-        Inkscape::Util::Unit const *unit = new Inkscape::Util::Unit(unitSelector->getUnit());
-
         if (result_sw == QUERY_STYLE_MULTIPLE_AVERAGED) {
             unitSelector->setUnit("%");
         } else {
             // same width, or only one object; no sense to keep percent, switch to absolute
-            if (unit->type != Inkscape::Util::UNIT_TYPE_LINEAR) {
+            Inkscape::Util::Unit const *tempunit = unitSelector->getUnit();
+            if (tempunit->type != Inkscape::Util::UNIT_TYPE_LINEAR) {
                 unitSelector->setUnit(sp_desktop_namedview(SP_ACTIVE_DESKTOP)->doc_units->abbr);
             }
         }
 
-        unit = new Inkscape::Util::Unit(unitSelector->getUnit());
+        Inkscape::Util::Unit const *unit = unitSelector->getUnit();
 
         if (unit->type == Inkscape::Util::UNIT_TYPE_LINEAR) {
-            double avgwidth = Inkscape::Util::Quantity::convert(query->stroke_width.computed, "px", *unit);
+            double avgwidth = Inkscape::Util::Quantity::convert(query->stroke_width.computed, "px", unit);
 #if WITH_GTKMM_3_0
             (*widthAdj)->set_value(avgwidth);
 #else
@@ -964,7 +964,7 @@ StrokeStyle::scaleLine()
         double const miterlimit = miterLimitAdj->get_value();
 #endif
 
-        Inkscape::Util::Unit const *const unit = new Inkscape::Util::Unit(unitSelector->getUnit());
+        Inkscape::Util::Unit const *const unit = unitSelector->getUnit();
 
         double *dash, offset;
         int ndash;
@@ -974,7 +974,7 @@ StrokeStyle::scaleLine()
             /* Set stroke width */
             double width;
             if (unit->type == Inkscape::Util::UNIT_TYPE_LINEAR) {
-                width = Inkscape::Util::Quantity::convert(width_typed, *unit, "px");
+                width = Inkscape::Util::Quantity::convert(width_typed, unit, "px");
             } else { // percentage
                 gdouble old_w = SP_OBJECT(i->data)->style->stroke_width.computed;
                 width = old_w * width_typed / 100;
diff --git a/src/widgets/stroke-style.h b/src/widgets/stroke-style.h
index 440881c6d..6f0fe583b 100644
--- a/src/widgets/stroke-style.h
+++ b/src/widgets/stroke-style.h
@@ -214,7 +214,7 @@ private:
     sigc::connection endMarkerConn;
     sigc::connection unitChangedConn;
     
-    Inkscape::Util::Unit *_old_unit;
+    Inkscape::Util::Unit const *_old_unit;
 };
 
 } // namespace Inkscape