Improve box interface.

pylene/include/mln/core/box.hpp

@@ -125,6 +125,22 @@ namespace mln::experimental
     /// \brief Returns the top-left corner point
     using Impl::tl;
 
+    /// \brief Returns the x coordinate of the top-left corner point
+    constexpr int x() const noexcept { return this->__begin(0); }
+
+    /// \brief Returns the y coordinate of the top-left corner point
+    template <int d = ndim, class = std::enable_if_t<d == -1 || d >= 2>>
+    constexpr int y() const noexcept { return this->__begin(1); }
+
+    /// \brief Returns the z coordinate of the top-left corner point
+    template <int d = ndim, class = std::enable_if_t<d == -1 || d >= 3>>
+    constexpr int z() const noexcept { return this->__begin(2); }
+
+    /// \brief Returns the w coordinate of the top-left corner point
+    template <int d = ndim, class = std::enable_if_t<d == -1 || d >= 4>>
+    constexpr int w() const noexcept { return this->__begin(3); }
+
+
     /// \brief Returns the k-th coordinate of the top-left corner point
     constexpr int tl(int k) const noexcept { return this->__begin(k); }
 
@@ -320,14 +336,30 @@ namespace mln::experimental
         assert(width >= 0);
       }
 
-      template <int d = D, class = std::enable_if_t<d == 2>>
-      constexpr _bstorage(int width, int height)
+
+      constexpr _bstorage(int x, int width) requires(D == 1)
+        : m_begin{x}
+        , m_end{x + width}
+      {
+        assert(width >= 0);
+      }
+
+
+      constexpr _bstorage(int width, int height) requires (D == 2)
         : m_begin{0, 0}
         , m_end{width, height}
       {
         assert(width >= 0 && height >= 0);
       }
 
+      constexpr _bstorage(int x, int y, int width, int height) requires(D == 2)
+        : m_begin{x, y}
+        , m_end{x + width, y + height}
+      {
+        assert(width >= 0 && height >= 0);
+      }
+
+
       template <int d = D, class = std::enable_if_t<d == 3>>
       constexpr _bstorage(int width, int height, int depth)
         : m_begin{0, 0, 0}
@@ -336,14 +368,31 @@ namespace mln::experimental
         assert(width >= 0 && height >= 0 && depth >= 0);
       }
 
-      template <int d = D, class = std::enable_if_t<d == 4>>
-      constexpr _bstorage(int width, int height, int depth, int duration)
+      template <int d = D, class = std::enable_if_t<d == 3>>
+      constexpr _bstorage(int x, int y, int z, int width, int height, int depth)
+        : m_begin{x, y, z}
+        , m_end{x + width, y + height, z + depth}
+      {
+        assert(width >= 0 && height >= 0 && depth >= 0);
+      }
+
+
+      constexpr _bstorage(int width, int height, int depth, int duration) requires (D == 4)
         : m_begin{0, 0, 0, 0}
         , m_end{width, height, depth, duration}
       {
         assert(width >= 0 && height >= 0 && depth >= 0 && duration >= 0);
       }
 
+      template <int d = D, class = std::enable_if_t<d == 4>>
+      constexpr _bstorage(int x, int y, int z, int w, int width, int height, int depth, int duration)
+        : m_begin{x, y, z, w}
+        , m_end{x + width, y + height, z + depth, w + duration}
+      {
+        assert(width >= 0 && height >= 0 && depth >= 0 && duration >= 0);
+      }
+
+
 
       static constexpr int dim() noexcept { return D; }
       constexpr const T*   data() const noexcept { return m_begin.data(); }