Improve CGAL::Image_3

- The type of `value_outside` is now directory `Return_type`: no need to
  apply the transformation.

- The indicator functions of the labelized trilinear interpolation can
  be changed.

CGAL_ImageIO/include/CGAL/Image_3.h

@@ -47,16 +47,23 @@ namespace CGAL {
 namespace ImageIO {
 
 template <typename T>
-class Indicator : public std::unary_function<T, double>
+struct Indicator_factory
 {
+  class Indicator : public std::unary_function<T, double>
+  {
     const T label;
-public:
+  public:
     Indicator(T i) : label(i) {};
 
     double operator()(T x) const
     {
       return (x == label) ? 1. : 0.;
     }
+  }; // end nested class Indicator
+
+  Indicator indicator(T i) const {
+    return Indicator(i);
+  }
 };
 
 } // end namespace CGAL::ImageIO
@@ -185,8 +192,8 @@ public:
   trilinear_interpolation(const Coord_type&x, 
 			  const Coord_type&y, 
 			  const Coord_type&z,
-			  const Image_word_type& value_outside = 
-			    Image_word_type(),
+			  const Target_word_type& value_outside =
+			    Target_word_type(),
 			  Image_transform transform = 
 			    Image_transform() ) const;
 
@@ -198,8 +205,8 @@ public:
   trilinear_interpolation(const Coord_type&x, 
 			  const Coord_type&y, 
 			  const Coord_type&z,
-			  const Image_word_type& value_outside = 
-			  Image_word_type()) const 
+			  const Target_word_type& value_outside =
+			  Target_word_type()) const
   {
     return trilinear_interpolation<
       Image_word_type,
@@ -208,13 +215,31 @@ public:
   }
 
   template <typename Image_word_type,
-	    typename Coord_type>
-  Image_word_type 
+	    typename Coord_type,
+            typename Target_word_type>
+  Target_word_type
   labellized_trilinear_interpolation(const Coord_type&x,
 				     const Coord_type&y,
 				     const Coord_type&z,
-				     const Image_word_type& value_outside = 
-  				       Image_word_type()) const;
+				     const Target_word_type& value_outside =
+  				       Target_word_type()) const
+  {
+    CGAL::ImageIO::Indicator_factory<Image_word_type> indicator_factory;
+    return labellized_trilinear_interpolation<Image_word_type>
+      (x, y, z, value_outside, indicator_factory);
+  }
+
+  template <typename Image_word_type,
+	    typename Coord_type,
+            typename Target_word_type,
+            typename Indicator_factory>
+  Target_word_type
+  labellized_trilinear_interpolation
+    (const Coord_type&x,
+     const Coord_type&y,
+     const Coord_type&z,
+     const Target_word_type& value_outside,
+     const Indicator_factory indicator_factory) const;
 
 }; // end Image_3
 
@@ -226,12 +251,12 @@ Target_word_type
 Image_3::trilinear_interpolation(const Coord_type& x, 
 				 const Coord_type& y, 
 				 const Coord_type& z,
-				 const Image_word_type& value_outside,
+				 const Target_word_type& value_outside,
 				 Image_transform transform) const 
 {
   // Check on double/float coordinates, because (int)-0.1 gives 0
   if ( x < 0 || y < 0 || z < 0 )
-    return Target_word_type(value_outside);
+    return value_outside;
   
   const Coord_type lx = x / image()->vx;
   const Coord_type ly = y / image()->vy;
@@ -248,7 +273,7 @@ Image_3::trilinear_interpolation(const Coord_type& x,
      ly >= dimy-1 ||
      lx >= dimx-1)
   {
-    return Target_word_type(transform(value_outside));
+    return value_outside;
   }  
 
   // images are indexed by (z,y,x)
@@ -411,12 +436,16 @@ Image_3::trilinear_interpolation(const Coord_type& x,
 
 
 template <typename Image_word_type,
-	  typename Coord_type>
-Image_word_type 
-Image_3::labellized_trilinear_interpolation(const Coord_type& x, 
+	  typename Coord_type,
+          typename Target_word_type,
+          typename Indicator_factory>
+Target_word_type
+Image_3::labellized_trilinear_interpolation
+  (const Coord_type& x,
    const Coord_type& y,
    const Coord_type& z,
-					    const Image_word_type& value_outside) const 
+   const Target_word_type& value_outside,
+   const Indicator_factory indicator_factory) const
 {
   // Check on double/float coordinates, because (int)-0.1 gives 0
   if ( x < 0 || y < 0 || z < 0 ) return value_outside;
@@ -481,15 +510,14 @@ Image_3::labellized_trilinear_interpolation(const Coord_type& x,
     return labels[0];
   }
     
-  typedef ImageIO::Indicator<Image_word_type> Indicator;
   double best_value = 0.;
   Image_word_type best = 0;
   for(int i = 0; i < lc; ++i)
   {
     Image_word_type iwt = labels[i];
     const double r = 
-      trilinear_interpolation<Image_word_type,double,Coord_type, Indicator>(
-        x, y, z, value_outside, Indicator(iwt));
+      trilinear_interpolation<Image_word_type,double,Coord_type>(
+        x, y, z, value_outside, indicator_factory.indicator(iwt));
     CGAL_assertion(r >= 0.);
     CGAL_assertion(r <= 1.);
 

Mesh_3/include/CGAL/Mesh_3/Image_to_labeled_function_wrapper.h

@@ -60,7 +60,7 @@ public:
   /// Constructor
   Image_to_labeled_function_wrapper(const Image_& image, 
                                     const Transform& transform = Transform(),
-                                    const Image_word_type value_outside = 0)
+                                    const Return_type value_outside = 0)
     : r_im_(image)
     , transform(transform)
     , value_outside(value_outside)
@@ -85,7 +85,7 @@ public:
       if ( labeled_image )
       {
         return static_cast<return_type>(transform(
-          r_im_.labellized_trilinear_interpolation(
+          r_im_.template labellized_trilinear_interpolation<Image_word_type>(
               CGAL::to_double(p.x()),
               CGAL::to_double(p.y()),
               CGAL::to_double(p.z()),
@@ -130,7 +130,7 @@ private:
   /// Labeled image to wrap
   const Image_& r_im_;
   const Transform transform;
-  const Image_word_type value_outside;
+  const Return_type value_outside;
 
 };  // end class Image_to_labeled_function_wrapper