Add lots of comments, and some code fixes discovered in the process.

9 files changed, 73 insertions, 19 deletions

diff --git a/libdimensionxx/dimensionxx/array.hpp b/libdimensionxx/dimensionxx/array.hpp
index dfbf1c8..735e17a 100644
--- a/libdimensionxx/dimensionxx/array.hpp
+++ b/libdimensionxx/dimensionxx/array.hpp
@@ -18,14 +18,14 @@
  * <http://www.gnu.org/licenses/>.                                       *
  *************************************************************************/
 
+// dmnsn_array* wrapper.
+
 #ifndef DIMENSIONXX_ARRAY_HPP
 #define DIMENSIONXX_ARRAY_HPP
 
 #include <tr1/memory> // For tr1::shared_ptr
 #include <cstdlib>    // For size_t
 
-// dmnsn_array* wrapper.
-
 namespace Dimension
 {
   // RAII scoped read-lock
@@ -148,6 +148,8 @@ namespace Dimension
     return ret;
   }
 
+  // Access the underlying dmnsn_array*
+
   template <typename T>
   dmnsn_array*
   Array<T>::dmnsn()
@@ -170,6 +172,7 @@ namespace Dimension
     return *m_array;
   }
 
+  // Release the dmnsn_array*, if we are the only Array holding it
   template <typename T>
   dmnsn_array*
   Array<T>::release()
diff --git a/libdimensionxx/dimensionxx/canvas.hpp b/libdimensionxx/dimensionxx/canvas.hpp
index eda9ad3..f9e77e5 100644
--- a/libdimensionxx/dimensionxx/canvas.hpp
+++ b/libdimensionxx/dimensionxx/canvas.hpp
@@ -18,11 +18,11 @@
  * <http://www.gnu.org/licenses/>.                                       *
  *************************************************************************/
 
+// dmnsn_canvas* wrapper.
+
 #ifndef DIMENSIONXX_CANVAS_HPP
 #define DIMENSIONXX_CANVAS_HPP
 
-// dmnsn_canvas* wrapper.
-
 namespace Dimension
 {
   // Base canvas class.  Wraps a dmnsn_canvas*.
diff --git a/libdimensionxx/dimensionxx/color.hpp b/libdimensionxx/dimensionxx/color.hpp
index c79f86b..9289479 100644
--- a/libdimensionxx/dimensionxx/color.hpp
+++ b/libdimensionxx/dimensionxx/color.hpp
@@ -18,11 +18,11 @@
  * <http://www.gnu.org/licenses/>.                                       *
  *************************************************************************/
 
+// Wrappers for libdimension colors.
+
 #ifndef DIMENSIONXX_COLOR_HPP
 #define DIMENSIONXX_COLOR_HPP
 
-// Wrappers for libdimension colors.
-
 namespace Dimension
 {
   // Forward declarations
diff --git a/libdimensionxx/dimensionxx/cookie.hpp b/libdimensionxx/dimensionxx/cookie.hpp
index df26b93..0d8b4da 100644
--- a/libdimensionxx/dimensionxx/cookie.hpp
+++ b/libdimensionxx/dimensionxx/cookie.hpp
@@ -18,11 +18,11 @@
  * <http://www.gnu.org/licenses/>.                                       *
  *************************************************************************/
 
+// Some internal magic to use C FILE* I/O with C++ streams.
+
 #ifndef DIMENSIONXX_COOKIE_HPP
 #define DIMENSIONXX_COOKIE_HPP
 
-// Some internal magic to use C FILE* I/O with C++ streams.
-
 #include <istream>
 #include <ostream>
 #include <cstdio>
diff --git a/libdimensionxx/dimensionxx/error.hpp b/libdimensionxx/dimensionxx/error.hpp
index 99670cb..7fb0e53 100644
--- a/libdimensionxx/dimensionxx/error.hpp
+++ b/libdimensionxx/dimensionxx/error.hpp
@@ -18,14 +18,14 @@
  * <http://www.gnu.org/licenses/>.                                       *
  *************************************************************************/
 
-#ifndef DIMENSIONXX_ERROR_HPP
-#define DIMENSIONXX_ERROR_HPP
-
 // Wrappers for libdimension error handling, and an exception class.
 // dmnsn_error is still used by libdimensionxx whenever an exception shouldn't
 // be thrown, like in destructors, and whenever libdimension or libdimension-*
 // use it internally.  Exceptions are thrown otherwise to report errors.
 
+#ifndef DIMENSIONXX_ERROR_HPP
+#define DIMENSIONXX_ERROR_HPP
+
 #include <dimension.h>
 #include <stdexcept>
 #include <string>
diff --git a/libdimensionxx/dimensionxx/geometry.hpp b/libdimensionxx/dimensionxx/geometry.hpp
index f623eda..606f83a 100644
--- a/libdimensionxx/dimensionxx/geometry.hpp
+++ b/libdimensionxx/dimensionxx/geometry.hpp
@@ -18,15 +18,17 @@
  * <http://www.gnu.org/licenses/>.                                       *
  *************************************************************************/
 
+// Wrappers for geometric types (Vectors, Matricies, Lines (rays)).
+
 #ifndef DIMENSIONXX_GEOMETRY_HPP
 #define DIMENSIONXX_GEOMETRY_HPP
 
-// Wrappers for geometric types (Vectors, Matricies, Lines (rays)).
-
 #include <dimension.h>
 
 namespace Dimension
 {
+  class Vector;
+
   // Wrapper for dmnsn_matrix
   class Matrix
   {
@@ -56,6 +58,12 @@ namespace Dimension
     // Get the wrapped matrix
     dmnsn_matrix dmnsn() const { return m_matrix; }
 
+    // Special constructors
+    static inline Matrix identity();
+    static inline Matrix scale(const Vector& factor);
+    static inline Matrix translation(const Vector& d);
+    static inline Matrix rotation(const Vector& theta);
+
   private:
     dmnsn_matrix m_matrix;
   };
@@ -126,6 +134,49 @@ namespace Dimension
     dmnsn_line m_line;
   };
 
+  // Matrix operators
+
+  inline Matrix
+  operator*(const Matrix& lhs, const Matrix& rhs)
+  {
+    // This order is important!
+    Matrix r = rhs;
+    r *= lhs;
+    return r;
+  }
+
+  inline Matrix
+  inverse(const Matrix& M)
+  {
+    return Matrix(dmnsn_matrix_inverse(M.dmnsn()));
+  }
+
+  // Special Matrix constructors
+
+  inline Matrix
+  Matrix::identity()
+  {
+    return Matrix(dmnsn_identity_matrix());
+  }
+
+  inline Matrix
+  Matrix::scale(const Vector& factor)
+  {
+    return Matrix(dmnsn_scale_matrix(factor.dmnsn()));
+  }
+
+  inline Matrix
+  Matrix::translation(const Vector& d)
+  {
+    return Matrix(dmnsn_translation_matrix(d.dmnsn()));
+  }
+
+  inline Matrix
+  Matrix::rotation(const Vector& theta)
+  {
+    return Matrix(dmnsn_rotation_matrix(theta.dmnsn()));
+  }
+
   // Vector operators
 
   inline Vector
diff --git a/libdimensionxx/dimensionxx/object.hpp b/libdimensionxx/dimensionxx/object.hpp
index 3b2c6c1..40dcb25 100644
--- a/libdimensionxx/dimensionxx/object.hpp
+++ b/libdimensionxx/dimensionxx/object.hpp
@@ -18,11 +18,11 @@
  * <http://www.gnu.org/licenses/>.                                       *
  *************************************************************************/
 
+// dmnsn_object* wrapper.
+
 #ifndef DIMENSIONXX_OBJECT_HPP
 #define DIMENSIONXX_OBJECT_HPP
 
-// dmnsn_object* wrapper.
-
 namespace Dimension
 {
   // Abstract base object class.  Wraps a dmnsn_object*.
diff --git a/libdimensionxx/dimensionxx/png.hpp b/libdimensionxx/dimensionxx/png.hpp
index d768287..980840c 100644
--- a/libdimensionxx/dimensionxx/png.hpp
+++ b/libdimensionxx/dimensionxx/png.hpp
@@ -18,11 +18,11 @@
  * <http://www.gnu.org/licenses/>.                                       *
  *************************************************************************/
 
+// C++ wrapper for libdimension PNG support.  PNG_Canvas derives from Canvas.
+
 #ifndef DIMENSIONXX_PNG_HPP
 #define DIMENSIONXX_PNG_HPP
 
-// C++ wrapper for libdimension PNG support.  PNG_Canvas derives from Canvas.
-
 #include <istream>
 #include <ostream>
 
diff --git a/libdimensionxx/dimensionxx/progress.hpp b/libdimensionxx/dimensionxx/progress.hpp
index b9df870..3fff1bc 100644
--- a/libdimensionxx/dimensionxx/progress.hpp
+++ b/libdimensionxx/dimensionxx/progress.hpp
@@ -18,14 +18,14 @@
  * <http://www.gnu.org/licenses/>.                                       *
  *************************************************************************/
 
+// dmnsn_progress* wrapper.
+
 #ifndef DIMENSIONXX_PROGRESS_HPP
 #define DIMENSIONXX_PROGRESS_HPP
 
 #include <tr1/memory> // For tr1::shared_ptr
 #include <list>
 
-// dmnsn_canvas* wrapper.
-
 namespace Dimension
 {
   // Base class for persisting objects