Edge-measure rulers too.

src/ant/ant/RulerConfigPage4.ui

@@ -6,8 +6,8 @@
    <rect>
     <x>0</x>
     <y>0</y>
-    <width>668</width>
-    <height>410</height>
+    <width>745</width>
+    <height>438</height>
    </rect>
   </property>
   <property name="windowTitle">
@@ -845,7 +845,12 @@
            </item>
            <item>
             <property name="text">
-             <string>Angle measurement (three mouse clicks)</string>
+             <string>Auto measure along edge (points will be set automatically)</string>
+            </property>
+           </item>
+           <item>
+            <property name="text">
+             <string>Angle or radius measurement (three mouse clicks)</string>
             </property>
            </item>
            <item>

src/ant/ant/antConfig.cc

@@ -247,6 +247,8 @@ RulerModeConverter::to_string (ant::Template::ruler_mode_type m)
     return "single_click";
   } else if (m == ant::Template::RulerAutoMetric) {
     return "auto_metric";
+  } else if (m == ant::Template::RulerAutoMetricEdge) {
+    return "auto_metric_edge";
   } else if (m == ant::Template::RulerMultiSegment) {
     return "multi_segment";
   } else if (m == ant::Template::RulerThreeClicks) {
@@ -266,6 +268,8 @@ RulerModeConverter::from_string (const std::string &s, ant::Template::ruler_mode
     a = ant::Template::RulerSingleClick;
   } else if (t == "auto_metric") {
     a = ant::Template::RulerAutoMetric;
+  } else if (t == "auto_metric_edge") {
+    a = ant::Template::RulerAutoMetricEdge;
   } else if (t == "multi_segment") {
     a = ant::Template::RulerMultiSegment;
   } else if (t == "angle") {

src/ant/ant/antPlugin.cc

@@ -60,6 +60,9 @@ static std::vector<ant::Template> make_standard_templates ()
   templates.push_back (ant::Template (tl::to_string (tr ("Measure")), "$X", "$Y", "$D", ant::Object::STY_ruler, ant::Object::OL_diag, true, lay::AC_Global, "_measure"));
   templates.back ().set_mode (ant::Template::RulerAutoMetric);
 
+  templates.push_back (ant::Template (tl::to_string (tr ("Measure edge")), "$X", "$Y", "$D", ant::Object::STY_ruler, ant::Object::OL_diag, true, lay::AC_Global, "_measure_edge"));
+  templates.back ().set_mode (ant::Template::RulerAutoMetricEdge);
+
   templates.push_back (ant::Template (tl::to_string (tr ("Angle")), "", "", "$(sprintf('%.5g',G))°", ant::Object::STY_line, ant::Object::OL_angle, true, lay::AC_Global, "_angle"));
   templates.back ().set_mode (ant::Template::RulerThreeClicks);
 

src/ant/ant/antService.cc

@@ -1910,6 +1910,29 @@ Service::mouse_click_event (const db::DPoint &p, unsigned int buttons, bool prio
 
         }
 
+      } else if (tpl.mode () == ant::Template::RulerAutoMetricEdge) {
+
+        lay::PointSnapToObjectResult snap_details = snap1_details (p, true);
+        if (snap_details.object_snap == lay::PointSnapToObjectResult::ObjectEdge) {
+
+          //  begin the transaction
+          if (manager ()) {
+            tl_assert (! manager ()->transacting ());
+            manager ()->transaction (tl::to_string (tr ("Create ruler")));
+          }
+
+          m_current = ant::Object (snap_details.object_ref.p1 (), snap_details.object_ref.p2 (), 0, tpl);
+          show_message ();
+
+          insert_ruler (m_current, true);
+
+          //  end the transaction
+          if (manager ()) {
+            manager ()->commit ();
+          }
+
+        }
+
       } else {
 
         m_p1 = snap1 (p, m_obj_snap && tpl.snap ()).second;
@@ -2006,7 +2029,7 @@ Service::mouse_move_event (const db::DPoint &p, unsigned int buttons, bool prio)
     snap_details = snap2_details (m_p1, p, mp_active_ruler->ruler (), ac_from_buttons (buttons));
   } else {
     const ant::Template &tpl = current_template ();
-    snap_details = snap1_details (p, m_obj_snap && tpl.snap ());
+    snap_details = snap1_details (p, m_obj_snap && tpl.snap () && (tpl.mode () != ant::Template::RulerAutoMetricEdge || ! view ()->transient_selection_mode ()));
   }
 
   mouse_cursor_from_snap_details (snap_details);
@@ -2356,24 +2379,38 @@ Service::timeout ()
 
   //  transiently create an auto-metric ruler if requested
 
+  ant::Object *ruler = 0;
+
   const ant::Template &tpl = current_template ();
   if (tpl.mode () == ant::Template::RulerAutoMetric) {
 
     lay::TwoPointSnapToObjectResult ee = auto_measure (m_hover_point, ac_from_buttons (m_hover_buttons), tpl);
     if (ee.any) {
-
       m_current = ant::Object (ee.first, ee.second, 0, tpl);
+      ruler = &m_current;
+    }
 
-      //  HINT: there is no special style for "transient selection on rulers"
-      mp_transient_ruler = new ant::View (this, &m_current, true /*not selected*/);
-
-      if (! editables ()->has_selection ()) {
-        display_status (true);
-      }
+  } else if (tpl.mode () == ant::Template::RulerAutoMetricEdge) {
 
+    lay::PointSnapToObjectResult snap_details = snap1_details (m_hover_point, true);
+    if (snap_details.object_snap == lay::PointSnapToObjectResult::ObjectEdge) {
+      m_current = ant::Object (snap_details.object_ref.p1 (), snap_details.object_ref.p2 (), 0, tpl);
+      ruler = &m_current;
     }
 
   }
+
+  if (ruler) {
+
+    //  HINT: there is no special style for "transient selection on rulers"
+    mp_transient_ruler = new ant::View (this, ruler, true /*not selected*/);
+
+    if (! editables ()->has_selection ()) {
+      display_status (true);
+    }
+
+  }
+
 }
 #endif
 

src/ant/ant/antTemplate.h

@@ -64,15 +64,20 @@ public:
      */
     RulerAutoMetric = 2,
 
+    /**
+     *  @brief The ruler is auto-metric along an edge: a single click will place a ruler and the ruler will extend to the edge below
+     */
+    RulerAutoMetricEdge = 3,
+
     /**
      *  @brief The ruler an angle type (two segments, three mouse clicks) for angle and circle radius measurements
      */
-    RulerThreeClicks = 3,
+    RulerThreeClicks = 4,
 
     /**
      *  @brief The ruler is a multi-segment type
      */
-    RulerMultiSegment = 4
+    RulerMultiSegment = 5
   };
 
   /**

src/ant/ant/gsiDeclAnt.cc

@@ -434,6 +434,11 @@ static int ruler_mode_auto_metric ()
   return ant::Template::RulerAutoMetric;
 }
 
+static int ruler_mode_auto_metric_edge ()
+{
+  return ant::Template::RulerAutoMetricEdge;
+}
+
 static int ruler_mode_three_clicks ()
 {
   return ant::Template::RulerThreeClicks;
@@ -525,6 +530,12 @@ gsi::Class<AnnotationRef> decl_Annotation (decl_BasicAnnotation, "lay", "Annotat
     "\n"
     "This constant has been introduced in version 0.25"
   ) +
+  gsi::method ("RulerModeAutoMetricEdge", &gsi::ruler_mode_auto_metric_edge,
+    "@brief Specifies edge-sensitive auto-metric ruler mode for the \\register_template method\n"
+    "In auto-metric mode, a ruler can be placed with a single click and p1/p2 will be determined from the edge it is placed on.\n"
+    "\n"
+    "This constant has been introduced in version 0.29"
+  ) +
   gsi::method ("RulerThreeClicks", &gsi::ruler_mode_three_clicks,
     "@brief Specifies three-click ruler mode for the \\register_template method\n"
     "In this ruler mode, two segments are created for angle and circle radius measurements. Three mouse clicks are required.\n"