Merge Google Summer of Code unit refactor.

(bzr r12471)

27 files changed, 606 insertions, 245 deletions

diff --git a/src/ui/CMakeLists.txt b/src/ui/CMakeLists.txt
index e831bcf69..b592d2527 100644
--- a/src/ui/CMakeLists.txt
+++ b/src/ui/CMakeLists.txt
@@ -112,6 +112,7 @@ set(ui_SRC
 	widget/text.cpp
 	widget/tolerance-slider.cpp
 	widget/unit-menu.cpp
+	widget/unit-tracker.cpp
 
 	view/view.cpp
 	view/view-widget.cpp
@@ -240,6 +241,7 @@ set(ui_SRC
 	widget/text.h
 	widget/tolerance-slider.h
 	widget/unit-menu.h
+	widget/unit-tracker.h
 
 	view/edit-widget-interface.h
 	view/view-widget.h
diff --git a/src/ui/clipboard.cpp b/src/ui/clipboard.cpp
index 72ddd90a9..629960613 100644
--- a/src/ui/clipboard.cpp
+++ b/src/ui/clipboard.cpp
@@ -79,7 +79,7 @@
 #include "text-editing.h"
 #include "tools-switch.h"
 #include "path-chemistry.h"
-#include "unit-constants.h"
+#include "util/units.h"
 #include "helper/png-write.h"
 #include "svg/svg-color.h"
 #include "sp-namedview.h"
@@ -1078,14 +1078,14 @@ void ClipboardManagerImpl::_onGet(Gtk::SelectionData &sel, guint /*info*/)
     try {
         if (out == outlist.end() && target == "image/png")
         {
-            gdouble dpi = PX_PER_IN;
+            gdouble dpi = Inkscape::Util::Quantity::convert(1, "in", "px");
             guint32 bgcolor = 0x00000000;
 
             Geom::Point origin (_clipboardSPDoc->getRoot()->x.computed, _clipboardSPDoc->getRoot()->y.computed);
             Geom::Rect area = Geom::Rect(origin, origin + _clipboardSPDoc->getDimensions());
 
-            unsigned long int width = (unsigned long int) (area.width() * dpi / PX_PER_IN + 0.5);
-            unsigned long int height = (unsigned long int) (area.height() * dpi / PX_PER_IN + 0.5);
+            unsigned long int width = (unsigned long int) (area.width() * dpi / Inkscape::Util::Quantity::convert(1, "in", "px") + 0.5);
+            unsigned long int height = (unsigned long int) (area.height() * dpi / Inkscape::Util::Quantity::convert(1, "in", "px") + 0.5);
 
             // read from namedview
             Inkscape::XML::Node *nv = sp_repr_lookup_name (_clipboardSPDoc->rroot, "sodipodi:namedview");
diff --git a/src/ui/dialog/clonetiler.cpp b/src/ui/dialog/clonetiler.cpp
index 753320ab9..b3675440b 100644
--- a/src/ui/dialog/clonetiler.cpp
+++ b/src/ui/dialog/clonetiler.cpp
@@ -34,8 +34,8 @@
 #include "document.h"
 #include "document-undo.h"
 #include "filter-chemistry.h"
-#include "helper/unit-menu.h"
-#include "helper/units.h"
+#include "ui/widget/unit-menu.h"
+#include "util/units.h"
 #include "helper/window.h"
 #include "inkscape.h"
 #include "interface.h"
@@ -58,6 +58,7 @@
 #include "sp-root.h"
 
 using Inkscape::DocumentUndo;
+using Inkscape::Util::unit_table;
 
 namespace Inkscape {
 namespace UI {
@@ -1092,35 +1093,36 @@ CloneTiler::CloneTiler (void) :
                 g_object_set_data (G_OBJECT(dlg), "widthheight", (gpointer) hb);
 
                 // unitmenu
-                GtkWidget *u = sp_unit_selector_new (SP_UNIT_ABSOLUTE | SP_UNIT_DEVICE);
-                sp_unit_selector_set_unit (SP_UNIT_SELECTOR(u), sp_desktop_namedview(SP_ACTIVE_DESKTOP)->doc_units);
+                unit_menu = new Inkscape::UI::Widget::UnitMenu();
+                unit_menu->setUnitType(Inkscape::Util::UNIT_TYPE_LINEAR);
+                unit_menu->setUnit(sp_desktop_namedview(SP_ACTIVE_DESKTOP)->doc_units->abbr);
+                unitChangedConn = unit_menu->signal_changed().connect(sigc::mem_fun(*this, &CloneTiler::clonetiler_unit_changed));
 
                 {
                     // Width spinbutton
 #if WITH_GTKMM_3_0
-                    Glib::RefPtr<Gtk::Adjustment> a = Gtk::Adjustment::create(0.0, -1e6, 1e6, 1.0, 10.0, 0);
+                    fill_width = Gtk::Adjustment::create(0.0, -1e6, 1e6, 1.0, 10.0, 0);
 #else
-                    Gtk::Adjustment *a = new Gtk::Adjustment (0.0, -1e6, 1e6, 1.0, 10.0, 0);
+                    fill_width = new Gtk::Adjustment (0.0, -1e6, 1e6, 1.0, 10.0, 0);
 #endif
-                    sp_unit_selector_add_adjustment (SP_UNIT_SELECTOR (u), GTK_ADJUSTMENT (a->gobj()));
 
                     double value = prefs->getDouble(prefs_path + "fillwidth", 50.0);
-                    SPUnit const &unit = *sp_unit_selector_get_unit(SP_UNIT_SELECTOR(u));
-                    gdouble const units = sp_pixels_get_units (value, unit);
-                    a->set_value (units);
+                    Inkscape::Util::Unit const unit = unit_menu->getUnit();
+                    gdouble const units = Inkscape::Util::Quantity::convert(value, "px", unit);
+                    fill_width->set_value (units);
 
 #if WITH_GTKMM_3_0
-                    Inkscape::UI::Widget::SpinButton *e = new Inkscape::UI::Widget::SpinButton(a, 1.0, 2);
+                    Inkscape::UI::Widget::SpinButton *e = new Inkscape::UI::Widget::SpinButton(fill_width, 1.0, 2);
 #else
-                    Inkscape::UI::Widget::SpinButton *e = new Inkscape::UI::Widget::SpinButton (*a, 1.0, 2);
+                    Inkscape::UI::Widget::SpinButton *e = new Inkscape::UI::Widget::SpinButton (*fill_width, 1.0, 2);
 #endif
                     e->set_tooltip_text (_("Width of the rectangle to be filled"));
                     e->set_width_chars (7);
                     e->set_digits (4);
                     gtk_box_pack_start (GTK_BOX (hb), GTK_WIDGET(e->gobj()), TRUE, TRUE, 0);
                     // TODO: C++ification
-            g_signal_connect(G_OBJECT(a->gobj()), "value_changed",
-                                       G_CALLBACK(clonetiler_fill_width_changed), u);
+            g_signal_connect(G_OBJECT(fill_width->gobj()), "value_changed",
+                                       G_CALLBACK(clonetiler_fill_width_changed), unit_menu);
                 }
                 {
                     GtkWidget *l = gtk_label_new ("");
@@ -1132,32 +1134,31 @@ CloneTiler::CloneTiler (void) :
                 {
                     // Height spinbutton
 #if WITH_GTKMM_3_0
-                    Glib::RefPtr<Gtk::Adjustment> a = Gtk::Adjustment::create(0.0, -1e6, 1e6, 1.0, 10.0, 0);
+                    fill_height = Gtk::Adjustment::create(0.0, -1e6, 1e6, 1.0, 10.0, 0);
 #else
-                    Gtk::Adjustment *a = new Gtk::Adjustment (0.0, -1e6, 1e6, 1.0, 10.0, 0);
+                    fill_height = new Gtk::Adjustment (0.0, -1e6, 1e6, 1.0, 10.0, 0);
 #endif
-                    sp_unit_selector_add_adjustment (SP_UNIT_SELECTOR (u), GTK_ADJUSTMENT (a->gobj()));
 
                     double value = prefs->getDouble(prefs_path + "fillheight", 50.0);
-                    SPUnit const &unit = *sp_unit_selector_get_unit(SP_UNIT_SELECTOR(u));
-                    gdouble const units = sp_pixels_get_units (value, unit);
-                    a->set_value (units);
+                    Inkscape::Util::Unit const unit = unit_menu->getUnit();
+                    gdouble const units = Inkscape::Util::Quantity::convert(value, "px", unit);
+                    fill_height->set_value (units);
 
 #if WITH_GTKMM_3_0
-                    Inkscape::UI::Widget::SpinButton *e = new Inkscape::UI::Widget::SpinButton(a, 1.0, 2);
+                    Inkscape::UI::Widget::SpinButton *e = new Inkscape::UI::Widget::SpinButton(fill_height, 1.0, 2);
 #else
-                    Inkscape::UI::Widget::SpinButton *e = new Inkscape::UI::Widget::SpinButton (*a, 1.0, 2);
+                    Inkscape::UI::Widget::SpinButton *e = new Inkscape::UI::Widget::SpinButton (*fill_height, 1.0, 2);
 #endif
                     e->set_tooltip_text (_("Height of the rectangle to be filled"));
                     e->set_width_chars (7);
                     e->set_digits (4);
                     gtk_box_pack_start (GTK_BOX (hb), GTK_WIDGET(e->gobj()), TRUE, TRUE, 0);
                     // TODO: C++ification
-            g_signal_connect(G_OBJECT(a->gobj()), "value_changed",
-                                       G_CALLBACK(clonetiler_fill_height_changed), u);
+            g_signal_connect(G_OBJECT(fill_height->gobj()), "value_changed",
+                                       G_CALLBACK(clonetiler_fill_height_changed), unit_menu);
                 }
 
-                gtk_box_pack_start (GTK_BOX (hb), u, TRUE, TRUE, 0);
+                gtk_box_pack_start (GTK_BOX (hb), (GtkWidget*) unit_menu->gobj(), TRUE, TRUE, 0);
                 clonetiler_table_attach (table, hb, 0.0, 2, 2);
 
             }
@@ -2944,26 +2945,39 @@ void CloneTiler::clonetiler_switch_to_fill(GtkToggleButton * /*tb*/, GtkWidget *
 
 
 
-void CloneTiler::clonetiler_fill_width_changed(GtkAdjustment *adj, GtkWidget *u)
+void CloneTiler::clonetiler_fill_width_changed(GtkAdjustment *adj, Inkscape::UI::Widget::UnitMenu *u)
 {
     gdouble const raw_dist = gtk_adjustment_get_value (adj);
-    SPUnit const &unit = *sp_unit_selector_get_unit(SP_UNIT_SELECTOR(u));
-    gdouble const pixels = sp_units_get_pixels (raw_dist, unit);
+    Inkscape::Util::Unit const unit = u->getUnit();
+    gdouble const pixels = Inkscape::Util::Quantity::convert(raw_dist, unit, "px");
 
     Inkscape::Preferences *prefs = Inkscape::Preferences::get();
     prefs->setDouble(prefs_path + "fillwidth", pixels);
 }
 
-void CloneTiler::clonetiler_fill_height_changed(GtkAdjustment *adj, GtkWidget *u)
+void CloneTiler::clonetiler_fill_height_changed(GtkAdjustment *adj, Inkscape::UI::Widget::UnitMenu *u)
 {
     gdouble const raw_dist = gtk_adjustment_get_value (adj);
-    SPUnit const &unit = *sp_unit_selector_get_unit(SP_UNIT_SELECTOR(u));
-    gdouble const pixels = sp_units_get_pixels (raw_dist, unit);
+    Inkscape::Util::Unit const unit = u->getUnit();
+    gdouble const pixels = Inkscape::Util::Quantity::convert(raw_dist, unit, "px");
 
     Inkscape::Preferences *prefs = Inkscape::Preferences::get();
     prefs->setDouble(prefs_path + "fillheight", pixels);
 }
 
+void CloneTiler::clonetiler_unit_changed()
+{
+    Inkscape::Preferences *prefs = Inkscape::Preferences::get();
+    gdouble width_pixels = prefs->getDouble(prefs_path + "fillwidth");
+    gdouble height_pixels = prefs->getDouble(prefs_path + "fillheight");
+    
+    Inkscape::Util::Unit 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);
+    gtk_adjustment_set_value(fill_width->gobj(), width_value);
+    gtk_adjustment_set_value(fill_height->gobj(), height_value);
+}
 
 void CloneTiler::clonetiler_do_pick_toggled(GtkToggleButton *tb, GtkWidget *dlg)
 {
@@ -2977,7 +2991,6 @@ void CloneTiler::clonetiler_do_pick_toggled(GtkToggleButton *tb, GtkWidget *dlg)
     }
 }
 
-
 }
 }
 }
diff --git a/src/ui/dialog/clonetiler.h b/src/ui/dialog/clonetiler.h
index 7ec30cfaa..e2a0240ee 100644
--- a/src/ui/dialog/clonetiler.h
+++ b/src/ui/dialog/clonetiler.h
@@ -19,6 +19,11 @@
 
 namespace Inkscape {
 namespace UI {
+
+namespace Widget {
+    class UnitMenu;
+}
+
 namespace Dialog {
 
 class CloneTiler : public Widget::Panel {
@@ -45,8 +50,9 @@ protected:
     static void clonetiler_do_pick_toggled(GtkToggleButton *tb, GtkWidget *dlg);
     static void clonetiler_pick_to(GtkToggleButton *tb, gpointer data);
     static void clonetiler_xy_changed(GtkAdjustment *adj, gpointer data);
-    static void clonetiler_fill_width_changed(GtkAdjustment *adj, GtkWidget *u);
-    static void clonetiler_fill_height_changed(GtkAdjustment *adj, GtkWidget *u);
+    static void clonetiler_fill_width_changed(GtkAdjustment *adj, Inkscape::UI::Widget::UnitMenu *u);
+    static void clonetiler_fill_height_changed(GtkAdjustment *adj, Inkscape::UI::Widget::UnitMenu *u);
+    void clonetiler_unit_changed();
     static void clonetiler_switch_to_create(GtkToggleButton */*tb*/, GtkWidget *dlg);
     static void clonetiler_switch_to_fill(GtkToggleButton */*tb*/, GtkWidget *dlg);
     static void clonetiler_keep_bbox_toggled(GtkToggleButton *tb, gpointer /*data*/);
@@ -112,12 +118,22 @@ private:
     DesktopTracker deskTrack;
     Inkscape::UI::Widget::ColorPicker *color_picker;
     GtkSizeGroup* table_row_labels;
+    Inkscape::UI::Widget::UnitMenu *unit_menu;
+
+#if WITH_GTKMM_3_0
+    Glib::RefPtr<Gtk::Adjustment> fill_width;
+    Glib::RefPtr<Gtk::Adjustment> fill_height;
+#else
+    Gtk::Adjustment *fill_width;
+    Gtk::Adjustment *fill_height;
+#endif
 
     sigc::connection desktopChangeConn;
     sigc::connection selectChangedConn;
     sigc::connection subselChangedConn;
     sigc::connection selectModifiedConn;
     sigc::connection color_changed_connection;
+    sigc::connection unitChangedConn;
 
     /**
      * Can be invoked for setting the desktop. Currently not used.
diff --git a/src/ui/dialog/document-properties.cpp b/src/ui/dialog/document-properties.cpp
index d335fb303..77fb182e5 100644
--- a/src/ui/dialog/document-properties.cpp
+++ b/src/ui/dialog/document-properties.cpp
@@ -28,7 +28,6 @@
 #include "document.h"
 #include "desktop-handles.h"
 #include "desktop.h"
-#include "helper/units.h"
 #include "inkscape.h"
 #include "io/sys.h"
 #include "preferences.h"
@@ -1432,7 +1431,7 @@ void DocumentProperties::update()
     _rcb_shad.setActive (nv->showpageshadow);
 
     if (nv->doc_units)
-        _rum_deflt.setUnit (nv->doc_units);
+        _rum_deflt.setUnit (nv->doc_units->abbr);
 
     double const doc_w_px = sp_desktop_document(dt)->getWidth();
     double const doc_h_px = sp_desktop_document(dt)->getHeight();
diff --git a/src/ui/dialog/export.cpp b/src/ui/dialog/export.cpp
index a851503fe..2c92608d7 100644
--- a/src/ui/dialog/export.cpp
+++ b/src/ui/dialog/export.cpp
@@ -48,9 +48,8 @@
 #include <glibmm/i18n.h>
 #include <glibmm/miscutils.h>
 
-#include "helper/unit-menu.h"
-#include "helper/units.h"
-#include "unit-constants.h"
+#include "ui/widget/unit-menu.h"
+#include "util/units.h"
 #include "helper/window.h"
 #include "inkscape-private.h"
 #include "document.h"
@@ -98,7 +97,7 @@
 
 #define SP_EXPORT_MIN_SIZE 1.0
 
-#define DPI_BASE PX_PER_IN
+#define DPI_BASE Inkscape::Util::Quantity::convert(1, "in", "px")
 
 #define EXPORT_COORD_PRECISION 3
 
@@ -108,6 +107,8 @@
 #include "verbs.h"
 #include "export.h"
 
+using Inkscape::Util::unit_table;
+
 namespace {
 
 class MessageCleaner
@@ -198,10 +199,13 @@ Export::Export (void) :
         /* Units box */
         /* gets added to the vbox later, but the unit selector is needed
            earlier than that */
-        unit_selector = Glib::wrap(sp_unit_selector_new (SP_UNIT_ABSOLUTE | SP_UNIT_DEVICE));
+        unit_selector = new Inkscape::UI::Widget::UnitMenu();
+        unit_selector->setUnitType(Inkscape::Util::UNIT_TYPE_LINEAR);
+        unitChangedConn = unit_selector->signal_changed().connect(sigc::mem_fun(*this, &Export::onUnitChanged));
+        
         SPDesktop *desktop = SP_ACTIVE_DESKTOP;
         if (desktop)
-            sp_unit_selector_set_unit (SP_UNIT_SELECTOR(unit_selector->gobj()), sp_desktop_namedview(desktop)->doc_units);
+            unit_selector->setUnit(sp_desktop_namedview(desktop)->doc_units->abbr);
         unitbox.pack_end(*unit_selector, false, false, 0);
         unitbox.pack_end(units_label, false, false, 3);
 
@@ -226,28 +230,28 @@ Export::Export (void) :
         t->set_col_spacings (4);
 #endif
 
-        x0_adj = createSpinbutton ( "x0", 0.0, -1000000.0, 1000000.0, 0.1, 1.0, unit_selector->gobj(),
+        x0_adj = createSpinbutton ( "x0", 0.0, -1000000.0, 1000000.0, 0.1, 1.0, ((Gtk::Widget*) unit_selector)->gobj(),
                                    t, 0, 0, _("_x0:"), "", EXPORT_COORD_PRECISION, 1,
                                    &Export::onAreaX0Change);
 
-        x1_adj = createSpinbutton ( "x1", 0.0, -1000000.0, 1000000.0, 0.1, 1.0, unit_selector->gobj(),
+        x1_adj = createSpinbutton ( "x1", 0.0, -1000000.0, 1000000.0, 0.1, 1.0, ((Gtk::Widget*) unit_selector)->gobj(),
                                    t, 0, 1, _("x_1:"), "", EXPORT_COORD_PRECISION, 1,
                                    &Export::onAreaX1Change);
 
         width_adj = createSpinbutton ( "width", 0.0, 0.0, PNG_UINT_31_MAX, 0.1, 1.0,
-                                   unit_selector->gobj(), t, 0, 2, _("Wid_th:"), "", EXPORT_COORD_PRECISION, 1,
+                                   ((Gtk::Widget*) unit_selector)->gobj(), t, 0, 2, _("Wid_th:"), "", EXPORT_COORD_PRECISION, 1,
                                    &Export::onAreaWidthChange);
 
-        y0_adj = createSpinbutton ( "y0", 0.0, -1000000.0, 1000000.0, 0.1, 1.0, unit_selector->gobj(),
+        y0_adj = createSpinbutton ( "y0", 0.0, -1000000.0, 1000000.0, 0.1, 1.0, ((Gtk::Widget*) unit_selector)->gobj(),
                                    t, 2, 0, _("_y0:"), "", EXPORT_COORD_PRECISION, 1,
                                    &Export::onAreaY0Change);
 
-        y1_adj = createSpinbutton ( "y1", 0.0, -1000000.0, 1000000.0, 0.1, 1.0, unit_selector->gobj(),
+        y1_adj = createSpinbutton ( "y1", 0.0, -1000000.0, 1000000.0, 0.1, 1.0, ((Gtk::Widget*) unit_selector)->gobj(),
                                    t, 2, 1, _("y_1:"), "", EXPORT_COORD_PRECISION, 1,
                                    &Export::onAreaY1Change);
 
         height_adj = createSpinbutton ( "height", 0.0, 0.0, PNG_UINT_31_MAX, 0.1, 1.0,
-                                   unit_selector->gobj(), t, 2, 2, _("Hei_ght:"), "", EXPORT_COORD_PRECISION, 1,
+                                   ((Gtk::Widget*) unit_selector)->gobj(), t, 2, 2, _("Hei_ght:"), "", EXPORT_COORD_PRECISION, 1,
                                    &Export::onAreaHeightChange);
 
         area_box.pack_start(togglebox, false, false, 3);
@@ -496,9 +500,6 @@ Gtk::Adjustment * Export::createSpinbutton( gchar const * /*key*/, float val, fl
 #else
     Gtk::Adjustment *adj = new Gtk::Adjustment  ( val, min, max, step, page, 0 );
 #endif
-    if (us) {
-        sp_unit_selector_add_adjustment ( SP_UNIT_SELECTOR (us), GTK_ADJUSTMENT (adj->gobj()) );
-    }
 
     int pos = 0;
     Gtk::Label *l = NULL;
@@ -979,6 +980,12 @@ Glib::ustring Export::absolutize_path_from_document_location (SPDocument *doc, c
     return path;
 }
 
+// Called when unit is changed
+void Export::onUnitChanged()
+{
+    onAreaToggled();
+}
+
 void Export::onHideExceptSelected ()
 {
     prefs->setBool("/dialogs/export/hideexceptselected/value", hide_export.get_active());
@@ -1042,8 +1049,8 @@ void Export::onExport ()
 
             Geom::OptRect area = item->desktopVisualBounds();
             if (area) {
-                gint width = (gint) (area->width() * dpi / PX_PER_IN + 0.5);
-                gint height = (gint) (area->height() * dpi / PX_PER_IN + 0.5);
+                gint width = (gint) (area->width() * dpi / DPI_BASE + 0.5);
+                gint height = (gint) (area->height() * dpi / DPI_BASE + 0.5);
 
                 if (width > 1 && height > 1) {
                     // Do export
@@ -1507,10 +1514,6 @@ void Export::areaXChange (Gtk::Adjustment *adj)
         return;
     }
 
-    if (sp_unit_selector_update_test(SP_UNIT_SELECTOR(unit_selector->gobj()))) {
-        return;
-    }
-
     update = true;
 
     x0 = getValuePx(x0_adj);
@@ -1554,10 +1557,6 @@ void Export::areaYChange (Gtk::Adjustment *adj)
         return;
     }
 
-    if (sp_unit_selector_update_test (SP_UNIT_SELECTOR(unit_selector->gobj())))  {
-        return;
-    }
-
     update = true;
 
     y0 = getValuePx(y0_adj);
@@ -1597,10 +1596,6 @@ void Export::onAreaWidthChange()
         return;
     }
 
-    if (sp_unit_selector_update_test(reinterpret_cast<SPUnitSelector *>(unit_selector->gobj()))) {
-        return;
-    }
-
     update = true;
 
     float x0 = getValuePx(x0_adj);
@@ -1630,10 +1625,6 @@ void Export::onAreaHeightChange()
         return;
     }
 
-    if (sp_unit_selector_update_test(reinterpret_cast<SPUnitSelector *>(unit_selector->gobj()))) {
-        return;
-    }
-
     update = true;
 
     float y0 = getValuePx(y0_adj);
@@ -1709,10 +1700,6 @@ void Export::onBitmapWidthChange ()
         return;
     }
 
-    if (sp_unit_selector_update_test(SP_UNIT_SELECTOR(unit_selector->gobj()))) {
-       return;
-    }
-
     update = true;
 
     x0 = getValuePx(x0_adj);
@@ -1743,10 +1730,6 @@ void Export::onBitmapHeightChange ()
         return;
     }
 
-    if (sp_unit_selector_update_test(SP_UNIT_SELECTOR(unit_selector->gobj()))) {
-       return;
-    }
-
     update = true;
 
     y0 = getValuePx(y0_adj);
@@ -1803,10 +1786,6 @@ void Export::onExportXdpiChange()
         return;
     }
 
-    if (sp_unit_selector_update_test(SP_UNIT_SELECTOR(unit_selector->gobj()))) {
-       return;
-    }
-
     update = true;
 
     x0 = getValuePx(x0_adj);
@@ -1905,9 +1884,9 @@ void Export::setValuePx(Glib::RefPtr<Gtk::Adjustment>& adj, double val)
 void Export::setValuePx( Gtk::Adjustment *adj, double val)
 #endif
 {
-    const SPUnit *unit = sp_unit_selector_get_unit(SP_UNIT_SELECTOR(unit_selector->gobj()) );
+    const Unit unit = unit_selector->getUnit();
 
-    setValue(adj, sp_pixels_get_units (val, *unit));
+    setValue(adj, Inkscape::Util::Quantity::convert(val, "px", unit));
 
     return;
 }
@@ -1955,9 +1934,9 @@ float Export::getValuePx(  Gtk::Adjustment *adj )
 #endif
 {
     float value = getValue( adj);
-    const SPUnit *unit = sp_unit_selector_get_unit(SP_UNIT_SELECTOR(unit_selector->gobj()));
+    const Unit unit = unit_selector->getUnit();
 
-    return sp_units_get_pixels (value, *unit);
+    return Inkscape::Util::Quantity::convert(value, unit, "px");
 } // end of sp_export_value_get_px()
 
 /**
diff --git a/src/ui/dialog/export.h b/src/ui/dialog/export.h
index b10c98fd2..f324f5dc5 100644
--- a/src/ui/dialog/export.h
+++ b/src/ui/dialog/export.h
@@ -172,6 +172,11 @@ private:
 #endif
 
     /**
+     * Unit changed callback
+     */
+    void onUnitChanged();
+
+    /**
      * Hide except selected callback
      */
     void onHideExceptSelected ();
@@ -330,7 +335,7 @@ private:
 
     /* Unit selector widgets */
     Gtk::HBox unitbox;
-    Gtk::Widget* unit_selector;
+    Inkscape::UI::Widget::UnitMenu *unit_selector;
     Gtk::Label units_label;
 
     /* Filename widgets  */
@@ -365,6 +370,7 @@ private:
     sigc::connection selectChangedConn;
     sigc::connection subselChangedConn;
     sigc::connection selectModifiedConn;
+    sigc::connection unitChangedConn;
 
 };
 
diff --git a/src/ui/dialog/guides.cpp b/src/ui/dialog/guides.cpp
index 51bbc7d9a..2de387364 100644
--- a/src/ui/dialog/guides.cpp
+++ b/src/ui/dialog/guides.cpp
@@ -230,7 +230,7 @@ void GuidelinePropertiesDialog::_setup() {
     _unit_menu.setUnitType(UNIT_TYPE_LINEAR);
     _unit_menu.setUnit("px");
     if (_desktop->namedview->doc_units) {
-        _unit_menu.setUnit( sp_unit_get_abbreviation(_desktop->namedview->doc_units) );
+        _unit_menu.setUnit( _desktop->namedview->doc_units->abbr );
     }
     _spin_angle.setUnit(_angle_unit_status);
 
diff --git a/src/ui/dialog/inkscape-preferences.cpp b/src/ui/dialog/inkscape-preferences.cpp
index bc648002d..7890b0b4c 100644
--- a/src/ui/dialog/inkscape-preferences.cpp
+++ b/src/ui/dialog/inkscape-preferences.cpp
@@ -28,7 +28,7 @@
 #include "preferences.h"
 #include "verbs.h"
 #include "selcue.h"
-#include "unit-constants.h"
+#include "util/units.h"
 #include <iostream>
 #include "enums.h"
 #include "desktop-handles.h"
@@ -1428,10 +1428,10 @@ void InkscapePreferences::initPageBitmaps()
                            _("Automatically reload linked images when file is changed on disk"));
     _misc_bitmap_editor.init("/options/bitmapeditor/value", true);
     _page_bitmaps.add_line( false, _("_Bitmap editor:"), _misc_bitmap_editor, "", "", true);
-    _importexport_export_res.init("/dialogs/export/defaultxdpi/value", 0.0, 6000.0, 1.0, 1.0, PX_PER_IN, true, false);
+    _importexport_export_res.init("/dialogs/export/defaultxdpi/value", 0.0, 6000.0, 1.0, 1.0, Inkscape::Util::Quantity::convert(1, "in", "px"), true, false);
     _page_bitmaps.add_line( false, _("Default export _resolution:"), _importexport_export_res, _("dpi"),
                             _("Default bitmap resolution (in dots per inch) in the Export dialog"), false);
-    _bitmap_copy_res.init("/options/createbitmap/resolution", 1.0, 6000.0, 1.0, 1.0, PX_PER_IN, true, false);
+    _bitmap_copy_res.init("/options/createbitmap/resolution", 1.0, 6000.0, 1.0, 1.0, Inkscape::Util::Quantity::convert(1, "in", "px"), true, false);
     _page_bitmaps.add_line( false, _("Resolution for Create Bitmap _Copy:"), _bitmap_copy_res, _("dpi"),
                             _("Resolution used by the Create Bitmap Copy command"), false);
     {
@@ -1443,7 +1443,7 @@ void InkscapePreferences::initPageBitmaps()
         _bitmap_import_quality.init("/dialogs/import/quality", 1, 100, 1, 1, 100, true, false);
         _page_bitmaps.add_line( false, _("Bitmap import quality:"), _bitmap_import_quality, "%", "Bitmap import quality (jpeg only). 100 is best quality", false);
     }
-    _importexport_import_res.init("/dialogs/import/defaultxdpi/value", 0.0, 6000.0, 1.0, 1.0, PX_PER_IN, true, false);
+    _importexport_import_res.init("/dialogs/import/defaultxdpi/value", 0.0, 6000.0, 1.0, 1.0, Inkscape::Util::Quantity::convert(1, "in", "px"), true, false);
     _page_bitmaps.add_line( false, _("Default _import resolution:"), _importexport_import_res, _("dpi"),
                             _("Default bitmap resolution (in dots per inch) for bitmap import"), false);
     _importexport_import_res_override.init(_("Override file resolution"), "/dialogs/import/forcexdpi", false);
diff --git a/src/ui/dialog/print.cpp b/src/ui/dialog/print.cpp
index 2ab8cf121..4c8c77f96 100644
--- a/src/ui/dialog/print.cpp
+++ b/src/ui/dialog/print.cpp
@@ -26,7 +26,7 @@
 #include "ui/widget/rendering-options.h"
 #include "document.h"
 
-#include "unit-constants.h"
+#include "util/units.h"
 #include "helper/png-write.h"
 #include "svg/svg-color.h"
 #include "io/sys.h"
@@ -72,8 +72,8 @@ static void draw_page(
 
             sp_export_png_file(junk->_doc, tmp_png.c_str(), 0.0, 0.0,
                 width, height,
-                (unsigned long)(width * dpi / PX_PER_IN),
-                (unsigned long)(height * dpi / PX_PER_IN),
+                (unsigned long)(width * dpi / Inkscape::Util::Quantity::convert(1, "in", "px")),
+                (unsigned long)(height * dpi / Inkscape::Util::Quantity::convert(1, "in", "px")),
                 dpi, dpi, bgcolor, NULL, NULL, true, NULL);
 
             // This doesn't seem to work:
@@ -90,7 +90,7 @@ static void draw_page(
                 cairo_t *cr = gtk_print_context_get_cairo_context (context);
                 cairo_matrix_t m;
                 cairo_get_matrix(cr, &m);
-                cairo_scale(cr, PT_PER_IN / dpi, PT_PER_IN / dpi);
+                cairo_scale(cr, Inkscape::Util::Quantity::convert(1, "in", "pt") / dpi, Inkscape::Util::Quantity::convert(1, "in", "pt") / dpi);
                 // FIXME: why is the origin offset??
                 cairo_set_source_surface(cr, png->cobj(), -16.0, -16.0);
                 cairo_paint(cr);
@@ -195,8 +195,8 @@ Print::Print(SPDocument *doc, SPItem *base) :
     // set up paper size to match the document size
     gtk_print_operation_set_unit (_printop, GTK_UNIT_POINTS);
     GtkPageSetup *page_setup = gtk_page_setup_new();
-    gdouble doc_width = _doc->getWidth() * PT_PER_PX;
-    gdouble doc_height = _doc->getHeight() * PT_PER_PX;
+    gdouble doc_width = _doc->getWidth() * Inkscape::Util::Quantity::convert(1, "px", "pt");
+    gdouble doc_height = _doc->getHeight() * Inkscape::Util::Quantity::convert(1, "px", "pt");
     GtkPaperSize *paper_size;
     if (doc_width > doc_height) {
         gtk_page_setup_set_orientation (page_setup, GTK_PAGE_ORIENTATION_LANDSCAPE);
diff --git a/src/ui/dialog/text-edit.cpp b/src/ui/dialog/text-edit.cpp
index a662495a0..4a25f723b 100644
--- a/src/ui/dialog/text-edit.cpp
+++ b/src/ui/dialog/text-edit.cpp
@@ -58,7 +58,7 @@ extern "C" {
 #include "widgets/font-selector.h"
 #include <glibmm/i18n.h>
 #include <glibmm/markup.h>
-#include "unit-constants.h"
+#include "util/units.h"
 #include "sp-textpath.h"
 
 namespace Inkscape {
@@ -401,7 +401,7 @@ void TextEdit::setPreviewText (Glib::ustring font_spec, Glib::ustring phrase)
 
     Inkscape::Preferences *prefs = Inkscape::Preferences::get();
     int unit = prefs->getInt("/options/font/unitType", SP_CSS_UNIT_PT);
-    double pt_size = sp_style_css_size_units_to_px(sp_font_selector_get_size(fsel), unit) * PT_PER_PX;
+    double pt_size = sp_style_css_size_units_to_px(sp_font_selector_get_size(fsel), unit) * Inkscape::Util::Quantity::convert(1, "px", "pt");
 
     // Pango font size is in 1024ths of a point
     // C++11: Glib::ustring size = std::to_string( pt_size * PANGO_SCALE );
diff --git a/src/ui/tool/node.cpp b/src/ui/tool/node.cpp
index dc6e0fbae..82eb697bd 100644
--- a/src/ui/tool/node.cpp
+++ b/src/ui/tool/node.cpp
@@ -22,7 +22,6 @@
 #include "preferences.h"
 #include "snap.h"
 #include "snap-preferences.h"
-#include "sp-metrics.h"
 #include "sp-namedview.h"
 #include "ui/control-manager.h"
 #include "ui/tool/control-point-selection.h"
@@ -490,9 +489,13 @@ Glib::ustring Handle::_getDragTip(GdkEventMotion */*event*/) const
     double angle = Geom::angle_between(Geom::Point(-1,0), position() - _parent->position());
     angle += M_PI; // angle is (-M_PI...M_PI] - offset by +pi and scale to 0...360
     angle *= 360.0 / (2 * M_PI);
-    GString *x = SP_PX_TO_METRIC_STRING(dist[Geom::X], _desktop->namedview->getDefaultMetric());
-    GString *y = SP_PX_TO_METRIC_STRING(dist[Geom::Y], _desktop->namedview->getDefaultMetric());
-    GString *len = SP_PX_TO_METRIC_STRING(length(), _desktop->namedview->getDefaultMetric());
+    
+    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());
     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);
@@ -1294,8 +1297,11 @@ Glib::ustring Node::_getTip(unsigned state) const
 Glib::ustring Node::_getDragTip(GdkEventMotion */*event*/) const
 {
     Geom::Point dist = position() - _last_drag_origin();
-    GString *x = SP_PX_TO_METRIC_STRING(dist[Geom::X], _desktop->namedview->getDefaultMetric());
-    GString *y = SP_PX_TO_METRIC_STRING(dist[Geom::Y], _desktop->namedview->getDefaultMetric());
+    
+    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);
     g_string_free(x, TRUE);
diff --git a/src/ui/widget/Makefile_insert b/src/ui/widget/Makefile_insert
index 2de954674..710b95c2b 100644
--- a/src/ui/widget/Makefile_insert
+++ b/src/ui/widget/Makefile_insert
@@ -79,5 +79,7 @@ ink_common_sources +=	\
 	ui/widget/tolerance-slider.cpp  \
 	ui/widget/tolerance-slider.h    \
 	ui/widget/unit-menu.cpp		\
-	ui/widget/unit-menu.h
+	ui/widget/unit-menu.h \
+	ui/widget/unit-tracker.h \
+	ui/widget/unit-tracker.cpp
 
diff --git a/src/ui/widget/page-sizer.cpp b/src/ui/widget/page-sizer.cpp
index 988c4e5de..8287452d7 100644
--- a/src/ui/widget/page-sizer.cpp
+++ b/src/ui/widget/page-sizer.cpp
@@ -37,7 +37,7 @@
 #include "desktop.h"
 #include "helper/action.h"
 #include "helper/action-context.h"
-#include "helper/units.h"
+#include "util/units.h"
 #include "inkscape.h"
 #include "sp-namedview.h"
 #include "sp-root.h"
@@ -48,6 +48,7 @@
 #include "xml/repr.h"
 
 using std::pair;
+using Inkscape::Util::unit_table;
 
 namespace Inkscape {
 namespace UI {
@@ -96,7 +97,7 @@ struct PaperSizeRec {
     char const * const name;  //name
     double const smaller;     //lesser dimension
     double const larger;      //greater dimension
-    SPUnitId const unit;      //units
+    Glib::ustring const unit;      //units
 };
 
 // list of page formats that should be in landscape automatically
@@ -114,31 +115,31 @@ fill_landscape_papers() {
 }
 
 static PaperSizeRec const inkscape_papers[] = {
-    { "A4",                210,  297, SP_UNIT_MM },
-    { "US Letter",         8.5,   11, SP_UNIT_IN },
-    { "US Legal",          8.5,   14, SP_UNIT_IN },
-    { "US Executive",     7.25, 10.5, SP_UNIT_IN },
-    { "A0",                841, 1189, SP_UNIT_MM },
-    { "A1",                594,  841, SP_UNIT_MM },
-    { "A2",                420,  594, SP_UNIT_MM },
-    { "A3",                297,  420, SP_UNIT_MM },
-    { "A5",                148,  210, SP_UNIT_MM },
-    { "A6",                105,  148, SP_UNIT_MM },
-    { "A7",                 74,  105, SP_UNIT_MM },
-    { "A8",                 52,   74, SP_UNIT_MM },
-    { "A9",                 37,   52, SP_UNIT_MM },
-    { "A10",                26,   37, SP_UNIT_MM },
-    { "B0",               1000, 1414, SP_UNIT_MM },
-    { "B1",                707, 1000, SP_UNIT_MM },
-    { "B2",                500,  707, SP_UNIT_MM },
-    { "B3",                353,  500, SP_UNIT_MM },
-    { "B4",                250,  353, SP_UNIT_MM },
-    { "B5",                176,  250, SP_UNIT_MM },
-    { "B6",                125,  176, SP_UNIT_MM },
-    { "B7",                 88,  125, SP_UNIT_MM },
-    { "B8",                 62,   88, SP_UNIT_MM },
-    { "B9",                 44,   62, SP_UNIT_MM },
-    { "B10",                31,   44, SP_UNIT_MM },
+    { "A4",                210,  297, "mm" },
+    { "US Letter",         8.5,   11, "in" },
+    { "US Legal",          8.5,   14, "in" },
+    { "US Executive",     7.25, 10.5, "in" },
+    { "A0",                841, 1189, "mm" },
+    { "A1",                594,  841, "mm" },
+    { "A2",                420,  594, "mm" },
+    { "A3",                297,  420, "mm" },
+    { "A5",                148,  210, "mm" },
+    { "A6",                105,  148, "mm" },
+    { "A7",                 74,  105, "mm" },
+    { "A8",                 52,   74, "mm" },
+    { "A9",                 37,   52, "mm" },
+    { "A10",                26,   37, "mm" },
+    { "B0",               1000, 1414, "mm" },
+    { "B1",                707, 1000, "mm" },
+    { "B2",                500,  707, "mm" },
+    { "B3",                353,  500, "mm" },
+    { "B4",                250,  353, "mm" },
+    { "B5",                176,  250, "mm" },
+    { "B6",                125,  176, "mm" },
+    { "B7",                 88,  125, "mm" },
+    { "B8",                 62,   88, "mm" },
+    { "B9",                 44,   62, "mm" },
+    { "B10",                31,   44, "mm" },
 
 
 
@@ -150,63 +151,63 @@ static PaperSizeRec const inkscape_papers[] = {
          don't know what D and E series are used for.
          */
 
-    { "C0",                917, 1297, SP_UNIT_MM },
-    { "C1",                648,  917, SP_UNIT_MM },
-    { "C2",                458,  648, SP_UNIT_MM },
-    { "C3",                324,  458, SP_UNIT_MM },
-    { "C4",                229,  324, SP_UNIT_MM },
-    { "C5",                162,  229, SP_UNIT_MM },
-    { "C6",                114,  162, SP_UNIT_MM },
-    { "C7",                 81,  114, SP_UNIT_MM },
-    { "C8",                 57,   81, SP_UNIT_MM },
-    { "C9",                 40,   57, SP_UNIT_MM },
-    { "C10",                28,   40, SP_UNIT_MM },
-    { "D1",                545,  771, SP_UNIT_MM },
-    { "D2",                385,  545, SP_UNIT_MM },
-    { "D3",                272,  385, SP_UNIT_MM },
-    { "D4",                192,  272, SP_UNIT_MM },
-    { "D5",                136,  192, SP_UNIT_MM },
-    { "D6",                 96,  136, SP_UNIT_MM },
-    { "D7",                 68,   96, SP_UNIT_MM },
-    { "E3",                400,  560, SP_UNIT_MM },
-    { "E4",                280,  400, SP_UNIT_MM },
-    { "E5",                200,  280, SP_UNIT_MM },
-    { "E6",                140,  200, SP_UNIT_MM },
+    { "C0",                917, 1297, "mm" },
+    { "C1",                648,  917, "mm" },
+    { "C2",                458,  648, "mm" },
+    { "C3",                324,  458, "mm" },
+    { "C4",                229,  324, "mm" },
+    { "C5",                162,  229, "mm" },
+    { "C6",                114,  162, "mm" },
+    { "C7",                 81,  114, "mm" },
+    { "C8",                 57,   81, "mm" },
+    { "C9",                 40,   57, "mm" },
+    { "C10",                28,   40, "mm" },
+    { "D1",                545,  771, "mm" },
+    { "D2",                385,  545, "mm" },
+    { "D3",                272,  385, "mm" },
+    { "D4",                192,  272, "mm" },
+    { "D5",                136,  192, "mm" },
+    { "D6",                 96,  136, "mm" },
+    { "D7",                 68,   96, "mm" },
+    { "E3",                400,  560, "mm" },
+    { "E4",                280,  400, "mm" },
+    { "E5",                200,  280, "mm" },
+    { "E6",                140,  200, "mm" },
 //#endif
 
 
 
-    { "CSE",               462,  649, SP_UNIT_PT },
-    { "US #10 Envelope", 4.125,  9.5, SP_UNIT_IN },
+    { "CSE",               462,  649, "pt" },
+    { "US #10 Envelope", 4.125,  9.5, "in" },
     /* See http://www.hbp.com/content/PCR_envelopes.cfm for a much larger list of US envelope
        sizes. */
-    { "DL Envelope",       110,  220, SP_UNIT_MM },
-    { "Ledger/Tabloid",     11,   17, SP_UNIT_IN },
+    { "DL Envelope",       110,  220, "mm" },
+    { "Ledger/Tabloid",     11,   17, "in" },
     /* Note that `Folio' (used in QPrinter/KPrinter) is deliberately absent from this list, as it
        means different sizes to different people: different people may expect the width to be
        either 8, 8.25 or 8.5 inches, and the height to be either 13 or 13.5 inches, even
        restricting our interpretation to foolscap folio.  If you wish to introduce a folio-like
        page size to the list, then please consider using a name more specific than just `Folio' or
        `Foolscap Folio'. */
-    { "Banner 468x60",      60,  468, SP_UNIT_PX },
-    { "Icon 16x16",         16,   16, SP_UNIT_PX },
-    { "Icon 32x32",         32,   32, SP_UNIT_PX },
-    { "Icon 48x48",         48,   48, SP_UNIT_PX },
+    { "Banner 468x60",      60,  468, "px" },
+    { "Icon 16x16",         16,   16, "px" },
+    { "Icon 32x32",         32,   32, "px" },
+    { "Icon 48x48",         48,   48, "px" },
     /* business cards */
-    { "Business Card (ISO 7810)", 53.98, 85.60, SP_UNIT_MM },
-    { "Business Card (US)",             2,     3.5,  SP_UNIT_IN },
-    { "Business Card (Europe)",        55,    85,    SP_UNIT_MM },
-    { "Business Card (Aus/NZ)",        55,    90,    SP_UNIT_MM },
+    { "Business Card (ISO 7810)", 53.98, 85.60, "mm" },
+    { "Business Card (US)",             2,     3.5,  "in" },
+    { "Business Card (Europe)",        55,    85,    "mm" },
+    { "Business Card (Aus/NZ)",        55,    90,    "mm" },
 
     // Start Arch Series List
 
 
-    { "Arch A",         9,    12,    SP_UNIT_IN },  // 229 x 305 mm
-    { "Arch B",        12,    18,    SP_UNIT_IN },  // 305 x 457 mm
-    { "Arch C",        18,    24,    SP_UNIT_IN },  // 457 x 610 mm
-    { "Arch D",        24,    36,    SP_UNIT_IN },  // 610 x 914 mm
-    { "Arch E",        36,    48,    SP_UNIT_IN },  // 914 x 1219 mm
-    { "Arch E1",       30,    42,    SP_UNIT_IN },  // 762 x 1067 mm
+    { "Arch A",         9,    12,    "in" },  // 229 x 305 mm
+    { "Arch B",        12,    18,    "in" },  // 305 x 457 mm
+    { "Arch C",        18,    24,    "in" },  // 457 x 610 mm
+    { "Arch D",        24,    36,    "in" },  // 610 x 914 mm
+    { "Arch E",        36,    48,    "in" },  // 914 x 1219 mm
+    { "Arch E1",       30,    42,    "in" },  // 762 x 1067 mm
 
     /*
      * The above list of Arch sizes were taken from the following site:
@@ -217,7 +218,7 @@ static PaperSizeRec const inkscape_papers[] = {
      * September 2009 - DAK
      */
 
-    { NULL,                     0,    0, SP_UNIT_PX },
+    { NULL,                     0,    0, "px" },
 };
 
 
@@ -226,10 +227,6 @@ static PaperSizeRec const inkscape_papers[] = {
 //# P A G E    S I Z E R
 //########################################################################
 
-//The default unit for this widget and its calculations
-static const SPUnit _px_unit = sp_unit_get_by_id (SP_UNIT_PX);
-
-
 /**
  * Constructor
  */
@@ -280,13 +277,8 @@ PageSizer::PageSizer(Registry & _wr)
         char formatBuf[80];
         snprintf(formatBuf, 79, "%0.1f x %0.1f", p->smaller, p->larger);
         Glib::ustring desc = formatBuf;
-        if (p->unit == SP_UNIT_IN)
-            desc.append(" in");
-        else if (p->unit == SP_UNIT_MM)
-             desc.append(" mm");
-        else if (p->unit == SP_UNIT_PX)
-            desc.append(" px");
-        PaperSize paper(name, p->smaller, p->larger, p->unit);
+        desc.append(" " + p->unit);
+        PaperSize paper(name, p->smaller, p->larger, unit_table.getUnit(p->unit));
         _paperSizeTable[name] = paper;
         Gtk::TreeModel::Row row = *(_paperSizeListStore->append());
         row[_paperSizeListColumns.nameColumn] = name;
@@ -320,9 +312,9 @@ PageSizer::PageSizer(Registry & _wr)
     SPNamedView *nv = sp_desktop_namedview(dt);
     _wr.setUpdating (true);
     if (nv->units) {
-        _dimensionUnits.setUnit(nv->units);
+        _dimensionUnits.setUnit(nv->units->abbr);
     } else if (nv->doc_units) {
-        _dimensionUnits.setUnit(nv->doc_units);
+        _dimensionUnits.setUnit(nv->doc_units->abbr);
     }
     _wr.setUpdating (false);
     
@@ -484,8 +476,8 @@ PageSizer::setDim (double w, double h, bool changeList)
     if (SP_ACTIVE_DESKTOP && !_widgetRegistry->isUpdating()) {
         SPDocument *doc = sp_desktop_document(SP_ACTIVE_DESKTOP);
         double const old_height = doc->getHeight();
-        doc->setWidth (w, &_px_unit);
-        doc->setHeight (h, &_px_unit);
+        doc->setWidth (Inkscape::Util::Quantity(w, "px"));
+        doc->setHeight (Inkscape::Util::Quantity(h, "px"));
         // The origin for the user is in the lower left corner; this point should remain stationary when
         // changing the page size. The SVG's origin however is in the upper left corner, so we must compensate for this
         Geom::Translate const vert_offset(Geom::Point(0, (old_height - h)));
@@ -569,9 +561,9 @@ PageSizer::find_paper_size (double w, double h) const
     for (iter = _paperSizeTable.begin() ;
          iter != _paperSizeTable.end() ; ++iter) {
         PaperSize paper = iter->second;
-        SPUnit const &i_unit = sp_unit_get_by_id(paper.unit);
-        double smallX = sp_units_get_pixels(paper.smaller, i_unit);
-        double largeX = sp_units_get_pixels(paper.larger,  i_unit);
+        Inkscape::Util::Unit const &i_unit = paper.unit;
+        double smallX = Inkscape::Util::Quantity::convert(paper.smaller, i_unit, "px");
+        double largeX = Inkscape::Util::Quantity::convert(paper.larger, i_unit, "px");
 
         g_return_val_if_fail(smallX <= largeX, _paperSizeListStore->children().end());
 
@@ -662,9 +654,8 @@ PageSizer::on_paper_size_list_changed()
         _landscape = _landscapeButton.get_active();
     }
 
-    SPUnit const &src_unit = sp_unit_get_by_id (paper.unit);
-    sp_convert_distance (&w, &src_unit, &_px_unit);
-    sp_convert_distance (&h, &src_unit, &_px_unit);
+    w = Inkscape::Util::Quantity::convert(w, paper.unit, "px");
+    h = Inkscape::Util::Quantity::convert(h, paper.unit, "px");
 
     if (_landscape)
         setDim (h, w, false);
diff --git a/src/ui/widget/page-sizer.h b/src/ui/widget/page-sizer.h
index d1fbb56e0..34ed7592d 100644
--- a/src/ui/widget/page-sizer.h
+++ b/src/ui/widget/page-sizer.h
@@ -18,7 +18,7 @@
 #include "ui/widget/registered-widget.h"
 #include <sigc++/sigc++.h>
 
-#include "helper/units.h"
+#include "util/units.h"
 
 #include <gtkmm/alignment.h>
 #include <gtkmm/expander.h>
@@ -64,7 +64,7 @@ public:
     PaperSize(const Glib::ustring &nameArg,
 	          double smallerArg,
 	          double largerArg,
-			  SPUnitId unitArg)
+			  Inkscape::Util::Unit unitArg)
 	    {
 	    name    = nameArg;
 	    smaller = smallerArg;
@@ -108,7 +108,7 @@ public:
     /**
      * The units (px, pt, mm, etc) of this specification
      */	     
-    SPUnitId unit;
+    Inkscape::Util::Unit unit;
 
 private:
 
@@ -117,7 +117,7 @@ private:
 	    name    = "";
 	    smaller = 0.0;
 	    larger  = 0.0;
-	    unit    = SP_UNIT_PX;
+	    unit    = unit_table.getUnit("px");
 	    }
 
 	void assign(const PaperSize &other)
diff --git a/src/ui/widget/registered-widget.cpp b/src/ui/widget/registered-widget.cpp
index ea2bac867..ae6a7d1e0 100644
--- a/src/ui/widget/registered-widget.cpp
+++ b/src/ui/widget/registered-widget.cpp
@@ -27,7 +27,6 @@
 #include "ui/widget/random.h"
 #include "widgets/spinbutton-events.h"
 
-#include "helper/units.h"
 #include "xml/repr.h"
 #include "svg/svg-color.h"
 #include "svg/stringstream.h"
@@ -118,9 +117,9 @@ RegisteredUnitMenu::RegisteredUnitMenu (const Glib::ustring& label, const Glib::
 }
 
 void
-RegisteredUnitMenu::setUnit (const SPUnit* unit)
+RegisteredUnitMenu::setUnit (Glib::ustring unit)
 {
-    getUnitMenu()->setUnit (sp_unit_get_abbreviation (unit));
+    getUnitMenu()->setUnit(unit);
 }
 
 void
diff --git a/src/ui/widget/registered-widget.h b/src/ui/widget/registered-widget.h
index 18a84ea05..93b0cef4e 100644
--- a/src/ui/widget/registered-widget.h
+++ b/src/ui/widget/registered-widget.h
@@ -32,7 +32,6 @@
 
 #include <gtkmm/checkbutton.h>
 
-struct SPUnit;
 class SPDocument;
 
 namespace Gtk {
@@ -167,7 +166,7 @@ public:
                          Inkscape::XML::Node* repr_in = NULL,
                          SPDocument *doc_in = NULL );
 
-    void setUnit (const SPUnit*);
+    void setUnit (const Glib::ustring);
     Unit 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/rendering-options.cpp b/src/ui/widget/rendering-options.cpp
index f26e71553..d6248df69 100644
--- a/src/ui/widget/rendering-options.cpp
+++ b/src/ui/widget/rendering-options.cpp
@@ -13,7 +13,7 @@
 #endif
 
 #include "rendering-options.h"
-#include "unit-constants.h"
+#include "util/units.h"
 #include <glibmm/i18n.h>
 
 namespace Inkscape {
@@ -59,8 +59,8 @@ RenderingOptions::RenderingOptions () :
     _radio_bitmap.signal_toggled().connect(sigc::mem_fun(*this, &RenderingOptions::_toggled));
 
     // configure default DPI
-    _dpi.setRange(PT_PER_IN,2400.0);
-    _dpi.setValue(PT_PER_IN);
+    _dpi.setRange(Inkscape::Util::Quantity::convert(1, "in", "pt"),2400.0);
+    _dpi.setValue(Inkscape::Util::Quantity::convert(1, "in", "pt"));
     _dpi.setIncrements(1.0,10.0);
     _dpi.setDigits(0);
     _dpi.update();
diff --git a/src/ui/widget/scalar-unit.cpp b/src/ui/widget/scalar-unit.cpp
index 99ff70846..2f4c1f341 100644
--- a/src/ui/widget/scalar-unit.cpp
+++ b/src/ui/widget/scalar-unit.cpp
@@ -16,6 +16,8 @@
 #include "scalar-unit.h"
 #include "spinbutton.h"
 
+using Inkscape::Util::unit_table;
+
 namespace Inkscape {
 namespace UI {
 namespace Widget {
@@ -226,9 +228,8 @@ void ScalarUnit::on_unit_changed()
     Glib::ustring abbr = _unit_menu->getUnitAbbr();
     _suffix->set_label(abbr);
 
-    Inkscape::Util::UnitTable &table = _unit_menu->getUnitTable();
-    Inkscape::Util::Unit new_unit = (table.getUnit(abbr));
-    Inkscape::Util::Unit old_unit = (table.getUnit(lastUnits));
+    Inkscape::Util::Unit new_unit = (unit_table.getUnit(abbr));
+    Inkscape::Util::Unit old_unit = (unit_table.getUnit(lastUnits));
 
     double convertedVal = 0;
     if (old_unit.type == UNIT_TYPE_DIMENSIONLESS && new_unit.type == UNIT_TYPE_LINEAR) {
diff --git a/src/ui/widget/selected-style.cpp b/src/ui/widget/selected-style.cpp
index 18dbb984b..388a0bcea 100644
--- a/src/ui/widget/selected-style.cpp
+++ b/src/ui/widget/selected-style.cpp
@@ -50,6 +50,9 @@
 #include "pixmaps/cursor-adj-a.xpm"
 #include "sp-cursor.h"
 #include "gradient-chemistry.h"
+#include "util/units.h"
+
+using Inkscape::Util::unit_table;
 
 static gdouble const _sw_presets[]     = { 32 ,  16 ,  10 ,  8 ,  6 ,  4 ,  3 ,  2 ,  1.5 ,  1 ,  0.75 ,  0.5 ,  0.25 ,  0.1 };
 static gchar const *const _sw_presets_str[] = {"32", "16", "10", "8", "6", "4", "3", "2", "1.5", "1", "0.75", "0.5", "0.25", "0.1"};
@@ -306,15 +309,17 @@ SelectedStyle::SelectedStyle(bool /*layout*/)
     {
         int row = 0;
 
-        // List of units should match with Fill/Stroke dialog stroke style width list
-        for (GSList *l = sp_unit_get_list(SP_UNIT_ABSOLUTE | SP_UNIT_DEVICE); l != NULL; l = l->next) {
-            SPUnit const *u = static_cast<SPUnit*>(l->data);
+        Inkscape::Util::UnitTable::UnitMap m = unit_table.units(Inkscape::Util::UNIT_TYPE_LINEAR);
+        Inkscape::Util::UnitTable::UnitMap::iterator iter = m.begin();
+        while(iter != m.end()) {
             Gtk::RadioMenuItem *mi = Gtk::manage(new Gtk::RadioMenuItem(_sw_group));
-            mi->add(*(new Gtk::Label(u->abbr, 0.0, 0.5)));
+            mi->add(*(new Gtk::Label((*iter).first, 0.0, 0.5)));
             _unit_mis = g_slist_append(_unit_mis, mi);
-            mi->signal_activate().connect(sigc::bind<SPUnitId>(sigc::mem_fun(*this, &SelectedStyle::on_popup_units), u->unit_id));
+            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));
             _popup_sw.attach(*mi, 0,1, row, row+1);
             row++;
+            ++iter;
         }
 
         _popup_sw.attach(*(new Gtk::SeparatorMenuItem()), 0,1, row, row+1);
@@ -476,13 +481,13 @@ SelectedStyle::setDesktop(SPDesktop *desktop)
             this )
     ));
 
-    _sw_unit = const_cast<SPUnit*>(sp_desktop_namedview(desktop)->doc_units);
+    _sw_unit = const_cast<Inkscape::Util::Unit*>(sp_desktop_namedview(desktop)->doc_units);
 
     // Set the doc default unit active in the units list
     gint length = g_slist_length(_unit_mis);
     for (int i = 0; i < length; i++) {
         Gtk::RadioMenuItem *mi = (Gtk::RadioMenuItem *) g_slist_nth_data(_unit_mis, i);
-        if (mi && mi->get_label() == Glib::ustring(_sw_unit->abbr)) {
+        if (mi && mi->get_label() == _sw_unit->abbr) {
             mi->set_active();
             break;
         }
@@ -926,8 +931,8 @@ SelectedStyle::on_opacity_click(GdkEventButton *event)
     return false;
 }
 
-void SelectedStyle::on_popup_units(SPUnitId id) {
-    _sw_unit = (SPUnit *) &(sp_unit_get_by_id(id));
+void SelectedStyle::on_popup_units(Inkscape::Util::Unit &unit) {
+    _sw_unit = new Inkscape::Util::Unit(unit);
     update();
 }
 
@@ -935,7 +940,7 @@ void SelectedStyle::on_popup_preset(int i) {
     SPCSSAttr *css = sp_repr_css_attr_new ();
     gdouble w;
     if (_sw_unit) {
-        w = sp_units_get_pixels (_sw_presets[i], *_sw_unit);
+        w = Inkscape::Util::Quantity::convert(_sw_presets[i], *_sw_unit, "px");
     } else {
         w = _sw_presets[i];
     }
@@ -1114,7 +1119,7 @@ SelectedStyle::update()
     {
         double w;
         if (_sw_unit) {
-            w = sp_pixels_get_units(query->stroke_width.computed, *_sw_unit);
+            w = Inkscape::Util::Quantity::convert(query->stroke_width.computed, "px", *_sw_unit);
         } else {
             w = query->stroke_width.computed;
         }
@@ -1128,7 +1133,7 @@ SelectedStyle::update()
         {
             gchar *str = g_strdup_printf(_("Stroke width: %.5g%s%s"),
                                          w,
-                                         _sw_unit? sp_unit_get_abbreviation(_sw_unit) : "px",
+                                         _sw_unit? _sw_unit->abbr.c_str() : "px",
                                          (result_sw == QUERY_STYLE_MULTIPLE_AVERAGED)?
                                          _(" (averaged)") : "");
             _stroke_width_place.set_tooltip_text(str);
diff --git a/src/ui/widget/selected-style.h b/src/ui/widget/selected-style.h
index e5bc4f883..0a907f1fd 100644
--- a/src/ui/widget/selected-style.h
+++ b/src/ui/widget/selected-style.h
@@ -41,12 +41,15 @@
 #include <sigc++/sigc++.h>
 
 #include "rotateable.h"
-#include "helper/units.h"
 
 class SPDesktop;
-struct SPUnit;
 
 namespace Inkscape {
+
+namespace Util {
+    class Unit;
+}
+
 namespace UI {
 namespace Widget {
 
@@ -273,11 +276,11 @@ protected:
     Gtk::Menu _popup_sw; 
     Gtk::RadioButtonGroup _sw_group;
     GSList *_unit_mis;
-    void on_popup_units(SPUnitId id);
+    void on_popup_units(Inkscape::Util::Unit &u);
     void on_popup_preset(int i);
     Gtk::MenuItem _popup_sw_remove;
 
-    SPUnit *_sw_unit;
+    Inkscape::Util::Unit *_sw_unit;
 
     void *_drop[2];
     bool _dropEnabled[2];
diff --git a/src/ui/widget/style-swatch.cpp b/src/ui/widget/style-swatch.cpp
index aedab3fa5..682457bed 100644
--- a/src/ui/widget/style-swatch.cpp
+++ b/src/ui/widget/style-swatch.cpp
@@ -26,7 +26,7 @@
 #include "xml/repr.h"
 #include "xml/sp-css-attr.h"
 #include "widgets/widget-sizes.h"
-#include "helper/units.h"
+#include "util/units.h"
 #include "helper/action.h"
 #include "helper/action-context.h"
 #include "preferences.h"
@@ -333,7 +333,7 @@ void StyleSwatch::setStyle(SPStyle *query)
     if (has_stroke) {
         double w;
         if (_sw_unit) {
-            w = sp_pixels_get_units(query->stroke_width.computed, *_sw_unit);
+            w = Inkscape::Util::Quantity::convert(query->stroke_width.computed, "px", *_sw_unit);
         } else {
             w = query->stroke_width.computed;
         }
@@ -346,7 +346,7 @@ void StyleSwatch::setStyle(SPStyle *query)
         {
             gchar *str = g_strdup_printf(_("Stroke width: %.5g%s"),
                                          w,
-                                         _sw_unit? sp_unit_get_abbreviation(_sw_unit) : "px");
+                                         _sw_unit? _sw_unit->abbr.c_str() : "px");
             _stroke_width_place.set_tooltip_text(str);
             g_free (str);
         }
diff --git a/src/ui/widget/style-swatch.h b/src/ui/widget/style-swatch.h
index 6bdb5e248..6da58a2dd 100644
--- a/src/ui/widget/style-swatch.h
+++ b/src/ui/widget/style-swatch.h
@@ -30,7 +30,6 @@
 #include "button.h"
 #include "preferences.h"
 
-struct SPUnit;
 struct SPStyle;
 class SPCSSAttr;
 
@@ -43,6 +42,11 @@ class Table;
 }
 
 namespace Inkscape {
+
+namespace Util {
+    class Unit;
+}
+
 namespace UI {
 namespace Widget {
 
@@ -93,7 +97,7 @@ private:
     Gtk::EventBox _stroke_width_place;
     Gtk::Label _stroke_width;
 
-    SPUnit *_sw_unit;
+    Inkscape::Util::Unit *_sw_unit;
 
 friend class ToolObserver;
 };
diff --git a/src/ui/widget/unit-menu.cpp b/src/ui/widget/unit-menu.cpp
index 18b7bcab9..111226774 100644
--- a/src/ui/widget/unit-menu.cpp
+++ b/src/ui/widget/unit-menu.cpp
@@ -15,6 +15,8 @@
 
 #include "unit-menu.h"
 
+using Inkscape::Util::unit_table;
+
 namespace Inkscape {
 namespace UI {
 namespace Widget {
@@ -30,7 +32,7 @@ UnitMenu::~UnitMenu() {
 bool UnitMenu::setUnitType(UnitType unit_type) 
 {
     // Expand the unit widget with unit entries from the unit table
-    UnitTable::UnitMap m = _unit_table.units(unit_type);
+    UnitTable::UnitMap m = unit_table.units(unit_type);
     UnitTable::UnitMap::iterator iter = m.begin();
     while(iter != m.end()) {
         Glib::ustring text = (*iter).first;
@@ -38,7 +40,7 @@ bool UnitMenu::setUnitType(UnitType unit_type)
         ++iter;
     }
     _type = unit_type;
-    set_active_text(_unit_table.primary(unit_type));
+    set_active_text(unit_table.primary(unit_type));
 
     return true;
 }
@@ -52,7 +54,7 @@ bool UnitMenu::resetUnitType(UnitType unit_type)
 
 void UnitMenu::addUnit(Unit const& u)
 {
-    _unit_table.addUnit(u, false);
+    unit_table.addUnit(u, false);
     append(u.abbr);
 }
 
@@ -60,9 +62,9 @@ Unit UnitMenu::getUnit() const
 {
     if (get_active_text() == "") {
         g_assert(_type != UNIT_TYPE_NONE);
-        return _unit_table.getUnit(_unit_table.primary(_type));
+        return unit_table.getUnit(unit_table.primary(_type));
     }
-    return _unit_table.getUnit(get_active_text());
+    return unit_table.getUnit(get_active_text());
 }
 
 bool UnitMenu::setUnit(Glib::ustring const & unit)
@@ -112,8 +114,8 @@ double UnitMenu::getConversion(Glib::ustring const &new_unit_abbr, Glib::ustring
 {
     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);
+        old_factor = unit_table.getUnit(old_unit_abbr).factor;
+    Unit new_unit = unit_table.getUnit(new_unit_abbr);
 
     // Catch the case of zero or negative unit factors (error!)
     if (old_factor < 0.0000001 ||
diff --git a/src/ui/widget/unit-menu.h b/src/ui/widget/unit-menu.h
index 3104d5aef..3f4df6bf9 100644
--- a/src/ui/widget/unit-menu.h
+++ b/src/ui/widget/unit-menu.h
@@ -127,10 +127,7 @@ public:
      */
     bool          isRadial() const;
 
-    UnitTable     &getUnitTable() {return _unit_table;}
-
 protected:
-    UnitTable     _unit_table;
     UnitType          _type;
 };
 
diff --git a/src/ui/widget/unit-tracker.cpp b/src/ui/widget/unit-tracker.cpp
new file mode 100644
index 000000000..5b2dc031b
--- /dev/null
+++ b/src/ui/widget/unit-tracker.cpp
@@ -0,0 +1,263 @@
+/*
+ * Inkscape::UI::Widget::UnitTracker
+ * Simple mediator to synchronize changes to unit menus
+ *
+ * Authors:
+ *   Jon A. Cruz <jon@joncruz.org>
+ *   Matthew Petroff <matthew@mpetroff.net>
+ *
+ * Copyright (C) 2007 Jon A. Cruz
+ * Copyright (C) 2013 Matthew Petroff
+ *
+ * Released under GNU GPL, read the file 'COPYING' for more information
+ */
+
+#include "unit-tracker.h"
+#include "ege-select-one-action.h"
+
+#define COLUMN_STRING 0
+
+using Inkscape::Util::UnitTable;
+using Inkscape::Util::unit_table;
+
+namespace Inkscape {
+namespace UI {
+namespace Widget {
+
+UnitTracker::UnitTracker(UnitType unit_type) :
+    _active(0),
+    _isUpdating(false),
+    _activeUnitInitialized(false),
+    _store(0),
+    _unitList(0),
+    _actionList(0),
+    _adjList(0),
+    _priorValues()
+{
+    _store = gtk_list_store_new(1, G_TYPE_STRING);
+    
+    GtkTreeIter iter;
+    UnitTable::UnitMap m = unit_table.units(unit_type);
+    UnitTable::UnitMap::iterator m_iter = m.begin();
+    while(m_iter != m.end()) {
+        Glib::ustring text = (*m_iter).first;
+        m_iter++;
+        gtk_list_store_append(_store, &iter);
+        gtk_list_store_set(_store, &iter, COLUMN_STRING, text.c_str(), -1);
+    }
+    gint count = gtk_tree_model_iter_n_children(GTK_TREE_MODEL(_store), 0);
+    if ((count > 0) && (_active > count)) {
+        _setActive(--count);
+    } else {
+        _setActive(_active);
+    }
+}
+
+UnitTracker::~UnitTracker()
+{
+    // Unhook weak references to GtkActions
+    while (_actionList) {
+        g_signal_handlers_disconnect_by_func(G_OBJECT(_actionList->data), (gpointer) _unitChangedCB, this);
+        g_object_weak_unref(G_OBJECT(_actionList->data), _actionFinalizedCB, this);
+        _actionList = g_slist_delete_link(_actionList, _actionList);
+    }
+
+    // Unhook weak references to GtkAdjustments
+    while (_adjList) {
+        g_object_weak_unref(G_OBJECT(_adjList->data), _adjustmentFinalizedCB, this);
+        _adjList = g_slist_delete_link(_adjList, _adjList);
+    }
+}
+
+bool UnitTracker::isUpdating() const
+{
+    return _isUpdating;
+}
+
+Inkscape::Util::Unit UnitTracker::getActiveUnit() const
+{
+    return _activeUnit;
+}
+
+void UnitTracker::setActiveUnit(Inkscape::Util::Unit const *unit)
+{
+    if (unit) {
+        GtkTreeIter iter;
+        int index = 0;
+        gboolean found = gtk_tree_model_get_iter_first(GTK_TREE_MODEL(_store), &iter);
+        while (found) {
+            gchar *storedUnit = 0;
+            gtk_tree_model_get(GTK_TREE_MODEL(_store), &iter, COLUMN_STRING, &storedUnit, -1);
+            if (storedUnit && (!unit->abbr.compare(storedUnit))) {
+                _setActive(index);
+                break;
+            }
+            
+            found = gtk_tree_model_iter_next(GTK_TREE_MODEL(_store), &iter);
+            index++;
+        }
+    }
+}
+
+void UnitTracker::setActiveUnitByAbbr(gchar const *abbr)
+{
+    Inkscape::Util::Unit u = unit_table.getUnit(abbr);
+    setActiveUnit(&u);
+}
+
+void UnitTracker::addAdjustment(GtkAdjustment *adj)
+{
+    if (!g_slist_find(_adjList, adj)) {
+        g_object_weak_ref(G_OBJECT(adj), _adjustmentFinalizedCB, this);
+        _adjList = g_slist_append(_adjList, adj);
+    }
+}
+
+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);
+}
+
+void UnitTracker::setFullVal(GtkAdjustment *adj, gdouble val)
+{
+    _priorValues[adj] = val;
+}
+
+GtkAction *UnitTracker::createAction(gchar const *name, gchar const *label, gchar const *tooltip)
+{
+    EgeSelectOneAction *act1 = ege_select_one_action_new(name, label, tooltip, NULL, GTK_TREE_MODEL(_store));
+    ege_select_one_action_set_label_column(act1, COLUMN_STRING);
+    if (_active) {
+        ege_select_one_action_set_active(act1, _active);
+    }
+
+    ege_select_one_action_set_appearance(act1, "minimal");
+    g_object_weak_ref(G_OBJECT(act1), _actionFinalizedCB, this);
+    g_signal_connect(G_OBJECT(act1), "changed", G_CALLBACK(_unitChangedCB), this);
+    _actionList = g_slist_append(_actionList, act1);
+
+    return GTK_ACTION(act1);
+}
+
+void UnitTracker::_unitChangedCB(GtkAction *action, gpointer data)
+{
+    if (action && data) {
+        EgeSelectOneAction *act = EGE_SELECT_ONE_ACTION(action);
+        gint active = ege_select_one_action_get_active(act);
+        UnitTracker *self = reinterpret_cast<UnitTracker *>(data);
+        self->_setActive(active);
+    }
+}
+
+void UnitTracker::_actionFinalizedCB(gpointer data, GObject *where_the_object_was)
+{
+    if (data && where_the_object_was) {
+        UnitTracker *self = reinterpret_cast<UnitTracker *>(data);
+        self->_actionFinalized(where_the_object_was);
+    }
+}
+
+void UnitTracker::_adjustmentFinalizedCB(gpointer data, GObject *where_the_object_was)
+{
+    if (data && where_the_object_was) {
+        UnitTracker *self = reinterpret_cast<UnitTracker *>(data);
+        self->_adjustmentFinalized(where_the_object_was);
+    }
+}
+
+void UnitTracker::_actionFinalized(GObject *where_the_object_was)
+{
+    GSList *target = g_slist_find(_actionList, where_the_object_was);
+    if (target) {
+        _actionList = g_slist_remove(_actionList, where_the_object_was);
+    } else {
+        g_warning("Received a finalization callback for unknown object %p", where_the_object_was);
+    }
+}
+
+void UnitTracker::_adjustmentFinalized(GObject *where_the_object_was)
+{
+    GSList *target = g_slist_find(_adjList, where_the_object_was);
+    if (target) {
+        _adjList = g_slist_remove(_adjList, where_the_object_was);
+    } else {
+        g_warning("Received a finalization callback for unknown object %p", where_the_object_was);
+    }
+}
+
+void UnitTracker::_setActive(gint active)
+{
+    if ( active != _active || !_activeUnitInitialized ) {
+        gint oldActive = _active;
+
+        GtkTreeIter iter;
+        gboolean found = gtk_tree_model_iter_nth_child(GTK_TREE_MODEL(_store), &iter, NULL, oldActive);
+        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);
+
+            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);
+                _activeUnit = newUnit;
+
+                if (_adjList) {
+                    _fixupAdjustments(unit, newUnit);
+                }
+
+            } else {
+                g_warning("Did not find new unit");
+            }
+        } else {
+            g_warning("Did not find old unit");
+        }
+
+        _active = active;
+
+        for ( GSList *cur = _actionList ; cur ; cur = g_slist_next(cur) ) {
+            if (IS_EGE_SELECT_ONE_ACTION(cur->data)) {
+                EgeSelectOneAction *act = EGE_SELECT_ONE_ACTION(cur->data);
+                ege_select_one_action_set_active(act, active);
+            }
+        }
+        
+        _activeUnitInitialized = true;
+    }
+}
+
+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) ) {
+        GtkAdjustment *adj = GTK_ADJUSTMENT(cur->data);
+        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) )
+        {
+            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) )
+        {
+            if (_priorValues.find(adj) != _priorValues.end()) {
+                val = Inkscape::Util::Quantity::convert(_priorValues[adj], "px", newUnit);
+            }
+        } else {
+            val = Inkscape::Util::Quantity::convert(oldVal, oldUnit, newUnit);
+        }
+
+        gtk_adjustment_set_value(adj, val);
+    }
+    _isUpdating = false;
+}
+
+} // namespace Widget
+} // namespace UI
+} // namespace Inkscape
diff --git a/src/ui/widget/unit-tracker.h b/src/ui/widget/unit-tracker.h
new file mode 100644
index 000000000..19559ae1c
--- /dev/null
+++ b/src/ui/widget/unit-tracker.h
@@ -0,0 +1,74 @@
+/*
+ * Inkscape::UI::Widget::UnitTracker
+ * Simple mediator to synchronize changes to unit menus
+ *
+ * Authors:
+ *   Jon A. Cruz <jon@joncruz.org>
+ *   Matthew Petroff <matthew@mpetroff.net>
+ *
+ * Copyright (C) 2007 Jon A. Cruz
+ * Copyright (C) 2013 Matthew Petroff
+ *
+ * Released under GNU GPL, read the file 'COPYING' for more information
+ */
+
+#ifndef INKSCAPE_UI_WIDGET_UNIT_TRACKER_H
+#define INKSCAPE_UI_WIDGET_UNIT_TRACKER_H
+
+#include <map>
+#include <gtk/gtk.h>
+
+#include "util/units.h"
+
+using Inkscape::Util::Unit;
+using Inkscape::Util::UnitType;
+
+namespace Inkscape {
+namespace UI {
+namespace Widget {
+
+class UnitTracker {
+public:
+    UnitTracker(UnitType unit_type);
+    virtual ~UnitTracker();
+
+    bool isUpdating() const;
+
+    void setActiveUnit(Inkscape::Util::Unit const *unit);
+    void setActiveUnitByAbbr(gchar const *abbr);
+    Inkscape::Util::Unit getActiveUnit() const;
+
+    void addUnit(Inkscape::Util::Unit const &u);
+    void addAdjustment(GtkAdjustment *adj);
+    void setFullVal(GtkAdjustment *adj, gdouble val);
+
+    GtkAction *createAction(gchar const *name, gchar const *label, gchar const *tooltip);
+
+protected:
+    UnitType _type;
+
+private:
+    static void _unitChangedCB(GtkAction *action, gpointer data);
+    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 _actionFinalized(GObject *where_the_object_was);
+    void _adjustmentFinalized(GObject *where_the_object_was);
+
+    gint _active;
+    bool _isUpdating;
+    Inkscape::Util::Unit _activeUnit;
+    bool _activeUnitInitialized;
+    GtkListStore *_store;
+    GSList *_unitList;
+    GSList *_actionList;
+    GSList *_adjList;
+    std::map <GtkAdjustment *, gdouble> _priorValues;
+};
+
+} // namespace Widget
+} // namespace UI
+} // namespace Inkscape
+
+#endif // INKSCAPE_UI_WIDGET_UNIT_TRACKER_H