experimental widget casting functionality

modules/viz/include/opencv2/viz/widgets.hpp

@@ -15,6 +15,8 @@ namespace temp_viz
         Widget& operator =(const Widget &other);
         
         ~Widget();
+
+        template<typename _W> _W cast();
     private:
         class Impl;
         Impl *impl_;
@@ -56,13 +58,10 @@ namespace temp_viz
         void setColor(const Color &color);
     };
     
-
     class CV_EXPORTS LineWidget : public Widget3D
     {
     public:
         LineWidget(const Point3f &pt1, const Point3f &pt2, const Color &color = Color::white());
-        LineWidget(const Widget &other) : Widget3D(other) {}
-        LineWidget& operator=(const Widget &other);
         
         void setLineWidth(float line_width);
         float getLineWidth();
@@ -158,4 +157,10 @@ namespace temp_viz
     private:
         struct ApplyCloudNormals;
     };
+
+    template<> CV_EXPORTS Widget3D Widget::cast<Widget3D>();
+    template<> CV_EXPORTS LineWidget Widget::cast<LineWidget>();
 }
+
+
+

modules/viz/src/simple_widgets.cpp

@@ -24,12 +24,6 @@ temp_viz::LineWidget::LineWidget(const Point3f &pt1, const Point3f &pt2, const C
     setColor(color);
 }
 
-temp_viz::LineWidget& temp_viz::LineWidget::operator=(const Widget &other)
-{
-    Widget3D::operator=(other);
-    return *this;
-}
-
 void temp_viz::LineWidget::setLineWidth(float line_width)
 {
     vtkLODActor *actor = vtkLODActor::SafeDownCast(WidgetAccessor::getProp(*this));
@@ -44,6 +38,12 @@ float temp_viz::LineWidget::getLineWidth()
     return actor->GetProperty()->GetLineWidth();
 }
 
+template<> temp_viz::LineWidget temp_viz::Widget::cast<temp_viz::LineWidget>()
+{
+    Widget3D widget = this->cast<Widget3D>();
+    return static_cast<LineWidget&>(widget);
+}
+
 ///////////////////////////////////////////////////////////////////////////////////////////////
 /// plane widget implementation
 

modules/viz/src/widget.cpp

@@ -165,6 +165,16 @@ void temp_viz::Widget3D::setColor(const Color &color)
     actor->Modified ();
 }
 
+template<> temp_viz::Widget3D temp_viz::Widget::cast<temp_viz::Widget3D>()
+{
+    vtkProp3D *actor = vtkProp3D::SafeDownCast(WidgetAccessor::getProp(*this));
+    CV_Assert(actor);
+
+    Widget3D widget;
+    WidgetAccessor::setProp(widget, actor);
+    return widget;
+}
+
 ///////////////////////////////////////////////////////////////////////////////////////////////
 /// widget2D implementation