Fix bug 1804946: Measurement tool is very slow when using grids

This move from Namedview to a new prefernecr point to not reload full namedview on meassure

5 files changed, 66 insertions, 41 deletions

diff --git a/src/attributes.cpp b/src/attributes.cpp
index 1c90682ef..1222d2669 100644
--- a/src/attributes.cpp
+++ b/src/attributes.cpp
@@ -128,9 +128,6 @@ static SPStyleProp const props[] = {
     {SP_ATTR_POSITION, "position"},
     {SP_ATTR_INKSCAPE_COLOR, "inkscape:color"},
     {SP_ATTR_INKSCAPE_LOCKED, "inkscape:locked"},
-    /* Measure tool */
-    {SP_ATTR_INKSCAPE_MEASURE_START, "inkscape:measure-start"},
-    {SP_ATTR_INKSCAPE_MEASURE_END,   "inkscape:measure-end"},
     /* SPImage */
     {SP_ATTR_X, "x"},
     {SP_ATTR_Y, "y"},
diff --git a/src/attributes.h b/src/attributes.h
index 2c4e74b50..1f0178fae 100644
--- a/src/attributes.h
+++ b/src/attributes.h
@@ -137,9 +137,6 @@ enum SPAttributeEnum : unsigned {
     SP_ATTR_POSITION,
     SP_ATTR_INKSCAPE_COLOR,
     SP_ATTR_INKSCAPE_LOCKED,
-    /* Measure tool */
-    SP_ATTR_INKSCAPE_MEASURE_START,
-    SP_ATTR_INKSCAPE_MEASURE_END,
     /* SPImage, SPRect, etc. */
     SP_ATTR_X,
     SP_ATTR_Y,
diff --git a/src/preferences.cpp b/src/preferences.cpp
index afdfad010..79b60191f 100644
--- a/src/preferences.cpp
+++ b/src/preferences.cpp
@@ -434,6 +434,17 @@ void Preferences::setBool(Glib::ustring const &pref_path, bool value)
 }
 
 /**
+ * Set an point attribute of a preference.
+ *
+ * @param pref_path Path of the preference to modify.
+ * @param value The new value of the pref attribute.
+ */
+void Preferences::setPoint(Glib::ustring const &pref_path, Geom::Point value)
+{
+    _setRawValue(pref_path, Glib::ustring::compose("%1",value[Geom::X]) + "," + Glib::ustring::compose("%1",value[Geom::Y]));
+}
+
+/**
  * Set an integer attribute of a preference.
  *
  * @param pref_path Path of the preference to modify.
@@ -819,6 +830,18 @@ bool Preferences::_extractBool(Entry const &v)
     }
 }
 
+Geom::Point Preferences::_extractPoint(Entry const &v)
+{
+    if (v.cached_point) return v.value_point;
+    v.cached_point = true;
+    gchar const *s = static_cast<gchar const *>(v._value);
+    gchar ** strarray = g_strsplit(s, ",", 2);
+    double newx = atoi(strarray[0]);
+    double newy = atoi(strarray[1]);
+    g_strfreev (strarray);
+    return Geom::Point(newx, newy);
+}
+
 int Preferences::_extractInt(Entry const &v)
 {
     if (v.cached_int) return v.value_int;
diff --git a/src/preferences.h b/src/preferences.h
index a18293a42..96b8074de 100644
--- a/src/preferences.h
+++ b/src/preferences.h
@@ -21,6 +21,7 @@
 #include <unordered_map>
 #include <utility>
 #include <vector>
+#include <2geom/point.h>
 
 #include "xml/repr.h"
 
@@ -126,7 +127,7 @@ public:
     public:
         ~Entry() = default;
         Entry() : _pref_path(""), _value(nullptr),
-        cached_bool(false), cached_int(false), cached_double(false), cached_unit(false), cached_color(false), cached_style(false) { 
+        cached_bool(false), cached_point(false), cached_int(false), cached_double(false), cached_unit(false), cached_color(false), cached_style(false) { 
         
         
         } // needed to enable use in maps
@@ -147,6 +148,13 @@ public:
         inline bool getBool(bool def=false) const;
 
         /**
+         * Interpret the preference as an point.
+         *
+         * @param def Default value if the preference is not set.
+         */
+        inline Geom::Point getPoint(Geom::Point def=Geom::Point()) const;
+
+        /**
          * Interpret the preference as an integer.
          *
          * @param def Default value if the preference is not set.
@@ -235,19 +243,20 @@ public:
         Glib::ustring getEntryName() const;
     private:
         Entry(Glib::ustring path, void const *v) : _pref_path(std::move(path)), _value(v),
-        cached_bool(false), cached_int(false), cached_double(false), cached_unit(false), cached_color(false), cached_style(false) {}
+        cached_bool(false), cached_point (false), cached_int (false), cached_double(false), cached_unit(false), cached_color(false), cached_style(false) {}
 
         Glib::ustring _pref_path;
         void const *_value;
         
         mutable bool value_bool;
+        mutable Geom::Point value_point;
         mutable int value_int;
         mutable double value_double;
         mutable Glib::ustring value_unit;
         mutable guint32 value_color;
         mutable SPCSSAttr* value_style;
 
-        mutable bool cached_bool, cached_int, cached_double, cached_unit, cached_color, cached_style;
+        mutable bool cached_bool, cached_point, cached_int, cached_double, cached_unit, cached_color, cached_style;
 
     };
 
@@ -320,6 +329,16 @@ public:
     }
 
     /**
+     * Retrieve a point.
+     *
+     * @param pref_path Path to the retrieved preference.
+     * @param def The default value to return if the preference is not set.
+     */
+    Geom::Point getPoint(Glib::ustring const &pref_path, Geom::Point def=Geom::Point()) {
+        return getEntry(pref_path).getPoint(def);
+    }
+
+    /**
      * Retrieve an integer.
      *
      * @param pref_path Path to the retrieved preference.
@@ -432,6 +451,11 @@ public:
     void setBool(Glib::ustring const &pref_path, bool value);
 
     /**
+     * Set a point value.
+     */
+    void setPoint(Glib::ustring const &pref_path, Geom::Point value);
+
+    /**
      * Set an integer value.
      */
     void setInt(Glib::ustring const &pref_path, int value);
@@ -537,6 +561,7 @@ protected:
      * that v._value is not NULL
      */
     bool _extractBool(Entry const &v);
+    Geom::Point _extractPoint(Entry const &v);
     int _extractInt(Entry const &v);
     double _extractDouble(Entry const &v);
     double _extractDouble(Entry const &v, Glib::ustring const &requested_unit);
@@ -603,6 +628,15 @@ inline bool Preferences::Entry::getBool(bool def) const
     }
 }
 
+inline Geom::Point Preferences::Entry::getPoint(Geom::Point def) const
+{
+    if (!this->isValid()) {
+        return def;
+    } else {
+        return Inkscape::Preferences::get()->_extractPoint(*this);
+    }
+}
+
 inline int Preferences::Entry::getInt(int def) const
 {
     if (!this->isValid()) {
diff --git a/src/ui/tools/measure-tool.cpp b/src/ui/tools/measure-tool.cpp
index ac9c36222..eee108bc0 100644
--- a/src/ui/tools/measure-tool.cpp
+++ b/src/ui/tools/measure-tool.cpp
@@ -398,41 +398,15 @@ MeasureTool::~MeasureTool()
 }
 
 Geom::Point MeasureTool::readMeasurePoint(bool is_start) {
-    SPDesktop *desktop = SP_ACTIVE_DESKTOP;
-    SPNamedView *namedview = desktop->namedview;
-    if(!namedview) {
-        return Geom::Point(Geom::infinity(),Geom::infinity());
-    }
-    char const * measure_point = is_start ? "inkscape:measure-start" : "inkscape:measure-end";
-    char const * measure_point_data = namedview->getAttribute (measure_point);
-    if(!measure_point_data) {
-        measure_point_data = "0,0";
-        namedview->setAttribute (measure_point, measure_point_data);
-    }
-    gchar ** strarray = g_strsplit(measure_point_data, ",", 2);
-    double newx, newy;
-    unsigned int success = sp_svg_number_read_d(strarray[0], &newx);
-    success += sp_svg_number_read_d(strarray[1], &newy);
-    g_strfreev (strarray);
-    if (success == 2) {
-        Geom::Point point_data(newx, newy);
-        return point_data;
-    }
-    return Geom::Point(Geom::infinity(),Geom::infinity());
-
+    Inkscape::Preferences *prefs = Inkscape::Preferences::get();
+    Glib::ustring measure_point = is_start ? "/tools/measure/measure-start" : "/tools/measure/measure-end";
+    return prefs->getPoint(measure_point, Geom::Point(Geom::infinity(),Geom::infinity()));
 }
 
 void MeasureTool::writeMeasurePoint(Geom::Point point, bool is_start) {
-    SPDesktop *desktop = SP_ACTIVE_DESKTOP;
-    SPNamedView *namedview = desktop->namedview;
-    if(!namedview) {
-        return;
-    }
-    std::stringstream meassure_point_str;
-    meassure_point_str.imbue(std::locale::classic());
-    meassure_point_str << point[Geom::X] << "," << point[Geom::Y];
-    gchar const *measure_point = is_start ? "inkscape:measure-start" : "inkscape:measure-end";
-    namedview->setAttribute (measure_point, meassure_point_str.str().c_str());
+    Inkscape::Preferences *prefs = Inkscape::Preferences::get();
+    Glib::ustring measure_point = is_start ? "/tools/measure/measure-start" : "/tools/measure/measure-end";
+    prefs->setPoint(measure_point, point);
 }
 
 //This function is used to reverse the Measure, I do it in two steps because when