Sketcher: Handling of right mouse button during handler execution

=================================================================

    Instead of terminating the handler, as mandated before this PR by ViewProviderSketch, ViewProviderSketch
    delegates the action to DrawSketchHandler.

    DrawSketchHandler implements by default this terminating behaviour, but allows to override it.

    DrawSketchDefaultHandler (and all tools deriving from it) implement as default behaviour to cancel if
    in initial state, otherwise to reset.

src/Mod/Sketcher/Gui/DrawSketchDefaultHandler.h

@@ -437,6 +437,19 @@ public:
             }
         }
     }
+
+    void pressRightButton(Base::Vector2d onSketchPos) override
+    {
+        Q_UNUSED(onSketchPos);
+
+        if (this->isFirstState()) {
+            quit();
+        }
+        else {
+            handleContinuousMode();
+        }
+    }
+
     //@}
 
 

src/Mod/Sketcher/Gui/DrawSketchHandler.cpp

@@ -378,6 +378,13 @@ void DrawSketchHandler::registerPressedKey(bool pressed, int key)
     }
 }
 
+void DrawSketchHandler::pressRightButton(Base::Vector2d /*onSketchPos*/)
+{
+    // the default behaviour is to quit - specific handler categories may
+    // override this behaviour, for example to implement a continuous mode
+    quit();
+}
+
 //**************************************************************************
 // Helpers
 

src/Mod/Sketcher/Gui/DrawSketchHandler.h

@@ -152,7 +152,8 @@ public:
     {
         return false;
     }
-    virtual void registerPressedKey(bool /*pressed*/, int /*key*/);
+    virtual void registerPressedKey(bool pressed, int key);
+    virtual void pressRightButton(Base::Vector2d onSketchPos);
 
     virtual void quit();
 

src/Mod/Sketcher/Gui/ViewProviderSketch.cpp

@@ -1169,8 +1169,8 @@ bool ViewProviderSketch::mouseButtonPressed(int Button, bool pressed, const SbVe
         if (!pressed) {
             switch (Mode) {
                 case STATUS_SKETCH_UseHandler:
-                    // make the handler quit
-                    sketchHandler->quit();
+                    // delegate to handler whether to quit or do otherwise
+                    sketchHandler->pressRightButton(Base::Vector2d(x, y));
                     return true;
                 case STATUS_NONE: {
                     // A right click shouldn't change the Edit Mode