Write C++ libdimension-png wrapper.

19 files changed, 729 insertions, 40 deletions

diff --git a/libdimension-png/dimension-png.h b/libdimension-png/dimension-png.h
index f8b4775..46ce82d 100644
--- a/libdimension-png/dimension-png.h
+++ b/libdimension-png/dimension-png.h
@@ -29,7 +29,7 @@ extern "C" {
 #endif
 
 int dmnsn_png_write_canvas(const dmnsn_canvas *canvas, FILE *file);
-int dmnsn_png_read_canvas(dmnsn_canvas **canvas, FILE *file);
+dmnsn_canvas *dmnsn_png_read_canvas(FILE *file);
 
 #ifdef __cplusplus
 }
diff --git a/libdimension-png/png.c b/libdimension-png/png.c
index 9bd22be..b639900 100644
--- a/libdimension-png/png.c
+++ b/libdimension-png/png.c
@@ -119,9 +119,10 @@ dmnsn_png_write_canvas(const dmnsn_canvas *canvas, FILE *file)
   return 0;
 }
 
-int
-dmnsn_png_read_canvas(dmnsn_canvas **canvas, FILE *file)
+dmnsn_canvas *
+dmnsn_png_read_canvas(FILE *file)
 {
+  dmnsn_canvas *canvas;
   png_byte header[8] = { 0, 0, 0, 0, 0, 0, 0, 0 };
   png_structp png_ptr;
   png_infop info_ptr;
@@ -134,28 +135,25 @@ dmnsn_png_read_canvas(dmnsn_canvas **canvas, FILE *file)
   dmnsn_sRGB sRGB;
   png_bytep png_pixel;
 
-  /* Ensure that *canvas can always be deleted. */
-  *canvas = NULL;
-
-  if (!file) return 1;
+  if (!file) return NULL;
 
   fread(header, 1, 8, file);
-  if (png_sig_cmp(header, 0, 8)) return 1;
+  if (png_sig_cmp(header, 0, 8)) return NULL;
 
   png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL);
-  if (!png_ptr) return 1;
+  if (!png_ptr) return NULL;
 
   info_ptr = png_create_info_struct(png_ptr);
   if (!info_ptr) {
     png_destroy_read_struct(&png_ptr, NULL, NULL);
-    return 1;
+    return NULL;
   }
 
   if (setjmp(png_jmpbuf(png_ptr))) {
     if (row_pointers) free(row_pointers);
     if (image) free(image);
     png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
-    return 1;
+    return NULL;
   }
 
   png_init_io(png_ptr, file);
@@ -190,14 +188,14 @@ dmnsn_png_read_canvas(dmnsn_canvas **canvas, FILE *file)
   image = malloc(rowbytes*height);
   if (!image) {
     png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
-    return 1;
+    return NULL;
   }
 
   row_pointers = malloc(sizeof(png_bytep)*height);
   if (!row_pointers) {
     free(image);
     png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
-    return 1;
+    return NULL;
   }
 
   for (y = 0; y < height; ++y) {
@@ -206,13 +204,13 @@ dmnsn_png_read_canvas(dmnsn_canvas **canvas, FILE *file)
 
   png_read_image(png_ptr, row_pointers);
 
-  *canvas = dmnsn_new_canvas(width, height);
-  if (!*canvas) {
+  canvas = dmnsn_new_canvas(width, height);
+  if (!canvas) {
     free(row_pointers);
     free(image);
     png_read_end(png_ptr, NULL);
     png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
-    return 1;
+    return NULL;
   }
 
   if (bit_depth == 16) {
@@ -231,7 +229,7 @@ dmnsn_png_read_canvas(dmnsn_canvas **canvas, FILE *file)
           color       = dmnsn_color_from_sRGB(sRGB);
           color.trans = ((double)((png_pixel[6] << UINT16_C(8))
                                   + png_pixel[7]))/UINT16_MAX;
-          dmnsn_set_pixel(*canvas, x, height - y - 1, color);
+          dmnsn_set_pixel(canvas, x, height - y - 1, color);
         }
       }
     } else {
@@ -247,7 +245,7 @@ dmnsn_png_read_canvas(dmnsn_canvas **canvas, FILE *file)
             /UINT16_MAX;
 
           color = dmnsn_color_from_sRGB(sRGB);
-          dmnsn_set_pixel(*canvas, x, height - y - 1, color);
+          dmnsn_set_pixel(canvas, x, height - y - 1, color);
         }
       }
     }
@@ -264,7 +262,7 @@ dmnsn_png_read_canvas(dmnsn_canvas **canvas, FILE *file)
 
           color       = dmnsn_color_from_sRGB(sRGB);
           color.trans = ((double)png_pixel[3])/UINT8_MAX;
-          dmnsn_set_pixel(*canvas, x, height - y - 1, color);
+          dmnsn_set_pixel(canvas, x, height - y - 1, color);
         }
       }
     } else {
@@ -277,7 +275,7 @@ dmnsn_png_read_canvas(dmnsn_canvas **canvas, FILE *file)
           sRGB.B = ((double)png_pixel[2])/UINT8_MAX;
 
           color = dmnsn_color_from_sRGB(sRGB);
-          dmnsn_set_pixel(*canvas, x, height - y - 1, color);
+          dmnsn_set_pixel(canvas, x, height - y - 1, color);
         }
       }
     }
@@ -287,5 +285,5 @@ dmnsn_png_read_canvas(dmnsn_canvas **canvas, FILE *file)
   free(image);
   png_read_end(png_ptr, NULL);
   png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
-  return 0;
+  return canvas;
 }
diff --git a/libdimension/color.c b/libdimension/color.c
index 4caf53b..e2a4df9 100644
--- a/libdimension/color.c
+++ b/libdimension/color.c
@@ -19,7 +19,7 @@
  *************************************************************************/
 
 #include "dimension.h"
-#include <math.h> /* For pow() */
+#include <math.h> /* For pow(), sqrt() */
 
 /* sRGB white point (D50) */
 const dmnsn_CIE_XYZ dmnsn_whitepoint = { .X = 0.9504060171449392,
@@ -253,3 +253,17 @@ dmnsn_color_add(dmnsn_color color1, dmnsn_color color2)
 
   return ret;
 }
+
+double
+dmnsn_color_difference(dmnsn_color color1, dmnsn_color color2)
+{
+  dmnsn_CIE_Lab Lab, Lab1, Lab2;
+  dmnsn_color ret;
+
+  Lab1 = dmnsn_Lab_from_color(color1, dmnsn_whitepoint);
+  Lab2 = dmnsn_Lab_from_color(color2, dmnsn_whitepoint);
+
+  return sqrt((Lab1.L - Lab2.L)*(Lab1.L - Lab2.L)
+              + (Lab1.a - Lab2.a)*(Lab1.a - Lab2.a)
+              + (Lab1.b - Lab2.b)*(Lab1.b - Lab2.b));
+}
diff --git a/libdimension/dimension.h b/libdimension/dimension.h
index 22fb700..df50524 100644
--- a/libdimension/dimension.h
+++ b/libdimension/dimension.h
@@ -36,7 +36,8 @@ typedef enum {
   DMNSN_SEVERITY_HIGH    /* Always die */
 } dmnsn_severity;
 
-#define dmnsn_error(severity, str) dmnsn_report_error(severity, __func__, str)
+#define dmnsn_error(severity, str)                              \
+  dmnsn_report_error(severity, __PRETTY_FUNCTION__, str)
 
 void dmnsn_report_error(dmnsn_severity severity,
                         const char *func, const char *str);
diff --git a/libdimension/dimension/color.h b/libdimension/dimension/color.h
index 5567628..0e64875 100644
--- a/libdimension/dimension/color.h
+++ b/libdimension/dimension/color.h
@@ -80,6 +80,7 @@ dmnsn_CIE_Luv dmnsn_Luv_from_color(dmnsn_color color, dmnsn_CIE_XYZ white);
 dmnsn_sRGB    dmnsn_sRGB_from_color(dmnsn_color color);
 
 dmnsn_color dmnsn_color_add(dmnsn_color color1, dmnsn_color color2);
+double dmnsn_color_difference(dmnsn_color color1, dmnsn_color color2);
 
 #ifdef __cplusplus
 }
diff --git a/libdimension/error.c b/libdimension/error.c
index 9dae673..6edf577 100644
--- a/libdimension/error.c
+++ b/libdimension/error.c
@@ -30,10 +30,10 @@ void
 dmnsn_report_error(dmnsn_severity severity, const char *func, const char *str)
 {
   if (severity >= dmnsn_get_resilience()) {
-    fprintf(stderr, "Dimension ERROR:   %s(): %s\n", func, str);
+    fprintf(stderr, "Dimension ERROR:   %s: %s\n", func, str);
     exit(EXIT_FAILURE);
   } else {
-    fprintf(stderr, "Dimension WARNING: %s(): %s\n", func, str);
+    fprintf(stderr, "Dimension WARNING: %s: %s\n", func, str);
   }
 }
 
@@ -42,12 +42,12 @@ dmnsn_get_resilience()
 {
   dmnsn_severity resilience;
   if (pthread_mutex_lock(&dmnsn_resilience_mutex) != 0) {
-    fprintf(stderr, "Dimension WARNING: %s(): %s\n", __func__,
+    fprintf(stderr, "Dimension WARNING: %s: %s\n", __PRETTY_FUNCTION__,
             "Couldn't lock resilience mutex.");
   }
   resilience = dmnsn_resilience;
   if (pthread_mutex_unlock(&dmnsn_resilience_mutex) != 0) {
-    fprintf(stderr, "Dimension WARNING: %s(): %s\n", __func__,
+    fprintf(stderr, "Dimension WARNING: %s: %s\n", __PRETTY_FUNCTION__,
             "Couldn't unlock resilience mutex.");
   }
   return resilience;
@@ -57,18 +57,18 @@ void
 dmnsn_set_resilience(dmnsn_severity resilience)
 {
   if (resilience > DMNSN_SEVERITY_HIGH) {
-    fprintf(stderr, "Dimension ERROR: %s(): %s\n", __func__,
+    fprintf(stderr, "Dimension ERROR: %s: %s\n", __PRETTY_FUNCTION__,
             "Resilience has wrong value.");
     exit(EXIT_FAILURE);
   }
 
   if (pthread_mutex_lock(&dmnsn_resilience_mutex) != 0) {
-    fprintf(stderr, "Dimension WARNING: %s(): %s\n", __func__,
+    fprintf(stderr, "Dimension WARNING: %s: %s\n", __PRETTY_FUNCTION__,
             "Couldn't lock resilience mutex.");
   }
   dmnsn_resilience = resilience;
   if (pthread_mutex_unlock(&dmnsn_resilience_mutex) != 0) {
-    fprintf(stderr, "Dimension WARNING: %s(): %s\n", __func__,
+    fprintf(stderr, "Dimension WARNING: %s: %s\n", __PRETTY_FUNCTION__,
             "Couldn't unlock resilience mutex.");
   }
 }
diff --git a/libdimensionxx/Makefile.am b/libdimensionxx/Makefile.am
index 39687fe..da8f544 100644
--- a/libdimensionxx/Makefile.am
+++ b/libdimensionxx/Makefile.am
@@ -17,12 +17,12 @@
 ## along with this program.  If not, see <http://www.gnu.org/licenses/>. ##
 ###########################################################################
 
-nobase_include_HEADERS = dimensionxx.hpp dimensionxx/geometry.hpp dimensionxx/color.hpp dimensionxx/canvas.hpp
+nobase_include_HEADERS = dimensionxx.hpp dimensionxx/canvas.hpp dimensionxx/color.hpp dimensionxx/cookie.hpp dimensionxx/geometry.hpp dimensionxx/png.hpp
 
 INCLUDES = -I../libdimension -I../libdimension-png
 
 lib_LTLIBRARIES = libdimensionxx.la
 
-libdimensionxx_la_SOURCES = dimensionxx.hpp dimensionxx/geometry.hpp dimensionxx/color.hpp dimensionxx/canvas.hpp canvas.cpp color.cpp geometry.cpp
+libdimensionxx_la_SOURCES = $(nobase_include_HEADERS) canvas.cpp color.cpp cookie.cpp geometry.cpp png.cpp
 libdimensionxx_la_LDFLAGS = -version-info 0:0:0
 libdimensionxx_la_LIBADD  = ../libdimension/libdimension.la ../libdimension-png/libdimension-png.la
diff --git a/libdimensionxx/cookie.cpp b/libdimensionxx/cookie.cpp
new file mode 100644
index 0000000..dd8a06d
--- /dev/null
+++ b/libdimensionxx/cookie.cpp
@@ -0,0 +1,163 @@
+/*************************************************************************
+ * Copyright (C) 2008 Tavian Barnes <tavianator@gmail.com>               *
+ *                                                                       *
+ * This file is part of The Dimension Library.                           *
+ *                                                                       *
+ * The Dimension Library is free software; you can redistribute it and/  *
+ * or modify it under the terms of the GNU Lesser General Public License *
+ * as published by the Free Software Foundation; either version 3 of the *
+ * License, or (at your option) any later version.                       *
+ *                                                                       *
+ * The Dimension Library is distributed in the hope that it will be      *
+ * useful, but WITHOUT ANY WARRANTY; without even the implied warranty   *
+ * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU  *
+ * Lesser General Public License for more details.                       *
+ *                                                                       *
+ * You should have received a copy of the GNU Lesser General Public      *
+ * License along with this program.  If not, see                         *
+ * <http://www.gnu.org/licenses/>.                                       *
+ *************************************************************************/
+
+#include "dimensionxx.hpp"
+#include <stdio.h>
+
+namespace Dimension
+{
+  namespace
+  {
+    struct Cookie
+    {
+    public:
+      std::istream* istr;
+      std::ostream* ostr;
+    };
+
+    ssize_t
+    cookie_read(void* cookie, char* buf, size_t size)
+    {
+      Cookie* streams = reinterpret_cast<Cookie*>(cookie);
+
+      streams->istr->read(buf, size);
+
+      if (streams->istr->eof()) {
+        return streams->istr->gcount();
+      } else if (!streams->istr->good()) {
+        return -1;
+      } else {
+        return streams->istr->gcount();
+      }
+    }
+
+    ssize_t
+    cookie_write(void* cookie, const char* buf, size_t size)
+    {
+      Cookie* streams = reinterpret_cast<Cookie*>(cookie);
+
+      streams->ostr->write(buf, size);
+
+      if (!streams->ostr->good()) {
+        return -1;
+      } else {
+        return size;
+      }
+    }
+
+    int
+    cookie_seek(void* cookie, off64_t* offset, int whence)
+    {
+      Cookie* streams = reinterpret_cast<Cookie*>(cookie);
+      bool success = true;
+
+      if (streams->istr) {
+        switch (whence) {
+        case SEEK_SET:
+          streams->istr->seekg(*offset, std::ios::beg);
+          break;
+        case SEEK_CUR:
+          streams->istr->seekg(*offset, std::ios::cur);
+          break;
+        case SEEK_END:
+          streams->istr->seekg(*offset, std::ios::end);
+          break;
+        }
+
+        if (!streams->istr->good()) {
+          success = false;
+        }
+      }
+
+      if (streams->ostr) {
+        switch (whence) {
+        case SEEK_SET:
+          streams->ostr->seekp(*offset, std::ios::beg);
+          break;
+        case SEEK_CUR:
+          streams->ostr->seekp(*offset, std::ios::cur);
+          break;
+        case SEEK_END:
+          streams->ostr->seekp(*offset, std::ios::end);
+        }
+
+        if (!streams->ostr->good()) {
+          success = false;
+        }
+      }
+
+      return !success;
+    }
+
+    int
+    cookie_close(void* cookie)
+    {
+      delete reinterpret_cast<Cookie*>(cookie);
+    }
+  }
+
+  std::FILE*
+  fcookie(std::istream& istr)
+  {
+    Cookie* cookie = new Cookie;
+    cookie->istr = &istr;
+    cookie->ostr = 0;
+
+    cookie_io_functions_t io_funcs;
+    io_funcs.read  = &cookie_read;
+    io_funcs.write = 0;
+    io_funcs.seek  = &cookie_seek;
+    io_funcs.close = &cookie_close;
+
+    return fopencookie(reinterpret_cast<void*>(cookie), "r", io_funcs);
+  }
+
+  std::FILE*
+  fcookie(std::ostream& ostr)
+  {
+    Cookie* cookie = new Cookie;
+    cookie->istr = 0;
+    cookie->ostr = &ostr;
+
+    cookie_io_functions_t io_funcs;
+    io_funcs.read  = 0;
+    io_funcs.write = &cookie_write;
+    io_funcs.seek  = &cookie_seek;
+    io_funcs.close = &cookie_close;
+
+    return fopencookie(reinterpret_cast<void*>(cookie), "w", io_funcs);
+  }
+
+  std::FILE*
+  fcookie(std::iostream& iostr)
+  {
+    Cookie* cookie = new Cookie;
+    cookie->istr = &iostr;
+    cookie->ostr = &iostr;
+
+    cookie_io_functions_t io_funcs;
+    io_funcs.read  = &cookie_read;
+    io_funcs.write = &cookie_write;
+    io_funcs.seek  = &cookie_seek;
+    io_funcs.close = &cookie_close;
+
+    return fopencookie(reinterpret_cast<void*>(cookie), "r+", io_funcs);
+  }
+}
diff --git a/libdimensionxx/dimensionxx.hpp b/libdimensionxx/dimensionxx.hpp
index a9e89d8..7714f73 100644
--- a/libdimensionxx/dimensionxx.hpp
+++ b/libdimensionxx/dimensionxx.hpp
@@ -21,9 +21,16 @@
 #ifndef DIMENSIONXX_HPP
 #define DIMENSIONXX_HPP
 
-/* More includes */
+// Internal helpers
+#include <dimensionxx/cookie.hpp>
+
+// libdimension wrappers
+#include <dimensionxx/error.hpp>
 #include <dimensionxx/geometry.hpp>
 #include <dimensionxx/color.hpp>
 #include <dimensionxx/canvas.hpp>
 
+// libdimension-png wrapper
+#include <dimensionxx/png.hpp>
+
 #endif /* DIMENSIONXX_HPP */
diff --git a/libdimensionxx/dimensionxx/canvas.hpp b/libdimensionxx/dimensionxx/canvas.hpp
index f51aa75..c501413 100644
--- a/libdimensionxx/dimensionxx/canvas.hpp
+++ b/libdimensionxx/dimensionxx/canvas.hpp
@@ -26,10 +26,14 @@ namespace Dimension
   class Canvas
   {
   public:
-    Canvas(unsigned int x, unsigned int y)
-      : m_canvas(dmnsn_new_canvas(x, y)) { }
+    Canvas(unsigned int width, unsigned int height)
+      : m_canvas(dmnsn_new_canvas(width, height)) { }
+    explicit Canvas(dmnsn_canvas* canvas) : m_canvas(canvas) { }
     virtual ~Canvas();
 
+    unsigned int width()  const { return m_canvas->x; }
+    unsigned int height() const { return m_canvas->y; }
+
     Color pixel(unsigned int x, unsigned int y) const
       { return Color(dmnsn_get_pixel(m_canvas, x, y)); }
     void pixel(unsigned int x, unsigned int y, const Color& c)
@@ -38,9 +42,12 @@ namespace Dimension
     dmnsn_canvas*       dmnsn()       { return m_canvas; }
     const dmnsn_canvas* dmnsn() const { return m_canvas; }
 
-  private:
+  protected:
+    Canvas() : m_canvas(0) { }
+
     dmnsn_canvas* m_canvas;
 
+  private:
     // Copying prohibited
     Canvas(const Canvas&);
     Canvas& operator=(const Canvas&);
diff --git a/libdimensionxx/dimensionxx/color.hpp b/libdimensionxx/dimensionxx/color.hpp
index 5db041a..afd7ea5 100644
--- a/libdimensionxx/dimensionxx/color.hpp
+++ b/libdimensionxx/dimensionxx/color.hpp
@@ -51,6 +51,8 @@ namespace Dimension
     double trans(double t)  { m_color.trans = t; }
 
     // Color& operator=(const Color& c);
+    Color& operator+=(const Color& c)
+      { m_color = dmnsn_color_add(m_color, c.m_color); return *this; }
 
     dmnsn_color dmnsn() const { return m_color; }
 
@@ -61,6 +63,7 @@ namespace Dimension
   class CIE_XYZ
   {
   public:
+    CIE_XYZ() { }
     CIE_XYZ(double X, double Y, double Z)
       { m_XYZ.X = X; m_XYZ.Y = Y; m_XYZ.Z = Z; }
     CIE_XYZ(const Color& c) : m_XYZ(dmnsn_XYZ_from_color(c.dmnsn())) { }
@@ -85,6 +88,7 @@ namespace Dimension
   class CIE_xyY
   {
   public:
+    CIE_xyY() { }
     CIE_xyY(double x, double y, double Y)
       { m_xyY.x = x; m_xyY.y = y; m_xyY.Y = Y; }
     CIE_xyY(const Color& c) : m_xyY(dmnsn_xyY_from_color(c.dmnsn())) { }
@@ -109,6 +113,7 @@ namespace Dimension
   class CIE_Lab
   {
   public:
+    CIE_Lab() { }
     CIE_Lab(double L, double a, double b)
       { m_Lab.L = L; m_Lab.a = a; m_Lab.b = b; }
     CIE_Lab(const Color& c, const CIE_XYZ& white = whitepoint)
@@ -134,6 +139,7 @@ namespace Dimension
   class CIE_Luv
   {
   public:
+    CIE_Luv() { }
     CIE_Luv(double L, double u, double v)
       { m_Luv.L = L; m_Luv.u = u; m_Luv.v = v; }
     CIE_Luv(const Color& c, const CIE_XYZ& white = whitepoint)
@@ -159,6 +165,7 @@ namespace Dimension
   class sRGB
   {
   public:
+    sRGB() { }
     sRGB(double R, double G, double B)
       { m_RGB.R = R; m_RGB.G = G; m_RGB.B = B; }
     sRGB(const Color& c) : m_RGB(dmnsn_sRGB_from_color(c.dmnsn())) { }
@@ -180,6 +187,8 @@ namespace Dimension
     dmnsn_sRGB m_RGB;
   };
 
+  // Color inline constructors
+
   inline Color::Color(const CIE_XYZ& XYZ)
     : m_color(dmnsn_color_from_XYZ(XYZ.dmnsn())) { }
 
@@ -194,6 +203,22 @@ namespace Dimension
 
   inline Color::Color(const sRGB& RGB)
     : m_color(dmnsn_color_from_sRGB(RGB.dmnsn())) { }
+
+  // Color operators
+
+  inline Color
+  operator+(const Color& lhs, const Color& rhs)
+  {
+    Color temp = lhs;
+    temp += rhs;
+    return temp;
+  }
+
+  inline double
+  operator-(const Color& lhs, const Color& rhs)
+  {
+    return dmnsn_color_difference(lhs.dmnsn(), rhs.dmnsn());
+  }
 }
 
 #endif /* DIMENSIONXX_COLOR_HPP */
diff --git a/libdimensionxx/dimensionxx/cookie.hpp b/libdimensionxx/dimensionxx/cookie.hpp
new file mode 100644
index 0000000..acb783d
--- /dev/null
+++ b/libdimensionxx/dimensionxx/cookie.hpp
@@ -0,0 +1,35 @@
+/*************************************************************************
+ * Copyright (C) 2008 Tavian Barnes <tavianator@gmail.com>               *
+ *                                                                       *
+ * This file is part of The Dimension Library.                           *
+ *                                                                       *
+ * The Dimension Library is free software; you can redistribute it and/  *
+ * or modify it under the terms of the GNU Lesser General Public License *
+ * as published by the Free Software Foundation; either version 3 of the *
+ * License, or (at your option) any later version.                       *
+ *                                                                       *
+ * The Dimension Library is distributed in the hope that it will be      *
+ * useful, but WITHOUT ANY WARRANTY; without even the implied warranty   *
+ * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU  *
+ * Lesser General Public License for more details.                       *
+ *                                                                       *
+ * You should have received a copy of the GNU Lesser General Public      *
+ * License along with this program.  If not, see                         *
+ * <http://www.gnu.org/licenses/>.                                       *
+ *************************************************************************/
+
+#ifndef DIMENSIONXX_COOKIE_HPP
+#define DIMENSIONXX_COOKIE_HPP
+
+#include <istream>
+#include <ostream>
+#include <cstdio>
+
+namespace Dimension
+{
+  std::FILE* fcookie(std::istream& istr);
+  std::FILE* fcookie(std::ostream& ostr);
+  std::FILE* fcookie(std::iostream& iostr);
+}
+
+#endif /* DIMENSIONXX_COOKIE_HPP */
diff --git a/libdimensionxx/dimensionxx/error.hpp b/libdimensionxx/dimensionxx/error.hpp
new file mode 100644
index 0000000..a6a4ca6
--- /dev/null
+++ b/libdimensionxx/dimensionxx/error.hpp
@@ -0,0 +1,30 @@
+/*************************************************************************
+ * Copyright (C) 2008 Tavian Barnes <tavianator@gmail.com>               *
+ *                                                                       *
+ * This file is part of The Dimension Library.                           *
+ *                                                                       *
+ * The Dimension Library is free software; you can redistribute it and/  *
+ * or modify it under the terms of the GNU Lesser General Public License *
+ * as published by the Free Software Foundation; either version 3 of the *
+ * License, or (at your option) any later version.                       *
+ *                                                                       *
+ * The Dimension Library is distributed in the hope that it will be      *
+ * useful, but WITHOUT ANY WARRANTY; without even the implied warranty   *
+ * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU  *
+ * Lesser General Public License for more details.                       *
+ *                                                                       *
+ * You should have received a copy of the GNU Lesser General Public      *
+ * License along with this program.  If not, see                         *
+ * <http://www.gnu.org/licenses/>.                                       *
+ *************************************************************************/
+
+#ifndef DIMENSIONXX_ERROR_HPP
+#define DIMENSIONXX_ERROR_HPP
+
+#include <dimension.h>
+
+namespace Dimension
+{
+}
+
+#endif /* DIMENSIONXX_ERROR_HPP */
diff --git a/libdimensionxx/dimensionxx/png.hpp b/libdimensionxx/dimensionxx/png.hpp
new file mode 100644
index 0000000..96ab2ca
--- /dev/null
+++ b/libdimensionxx/dimensionxx/png.hpp
@@ -0,0 +1,59 @@
+/*************************************************************************
+ * Copyright (C) 2008 Tavian Barnes <tavianator@gmail.com>               *
+ *                                                                       *
+ * This file is part of The Dimension Library.                           *
+ *                                                                       *
+ * The Dimension Library is free software; you can redistribute it and/  *
+ * or modify it under the terms of the GNU Lesser General Public License *
+ * as published by the Free Software Foundation; either version 3 of the *
+ * License, or (at your option) any later version.                       *
+ *                                                                       *
+ * The Dimension Library is distributed in the hope that it will be      *
+ * useful, but WITHOUT ANY WARRANTY; without even the implied warranty   *
+ * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU  *
+ * Lesser General Public License for more details.                       *
+ *                                                                       *
+ * You should have received a copy of the GNU Lesser General Public      *
+ * License along with this program.  If not, see                         *
+ * <http://www.gnu.org/licenses/>.                                       *
+ *************************************************************************/
+
+#ifndef DIMENSIONXX_PNG_HPP
+#define DIMENSIONXX_PNG_HPP
+
+#include <istream>
+#include <ostream>
+
+namespace Dimension
+{
+  class PNG_Canvas : public Canvas
+  {
+  public:
+    explicit PNG_Canvas(std::istream& istr)
+      : Canvas(), m_istr(&istr), m_ostr(0), m_written(false) { read(); }
+    PNG_Canvas(unsigned int x, unsigned int y, std::ostream& ostr)
+      : Canvas(x, y), m_istr(0), m_ostr(&ostr), m_written(false) { }
+    PNG_Canvas(std::istream& istr, std::ostream& ostr)
+      : Canvas(), m_istr(&istr), m_ostr(&ostr), m_written(false) { read(); }
+    virtual ~PNG_Canvas();
+
+    void write();
+
+  protected:
+    PNG_Canvas(std::ostream* ostr)
+      : Canvas(), m_istr(0), m_ostr(ostr), m_written(false) { }
+
+  private:
+    std::istream* m_istr;
+    std::ostream* m_ostr;
+    bool m_written;
+
+    void read();
+
+    // Copying prohibited
+    PNG_Canvas(const PNG_Canvas&);
+    PNG_Canvas& operator=(const PNG_Canvas&);
+  };
+}
+
+#endif /* DIMENSIONXX_PNG_HPP */
diff --git a/libdimensionxx/png.cpp b/libdimensionxx/png.cpp
new file mode 100644
index 0000000..14b8c4d
--- /dev/null
+++ b/libdimensionxx/png.cpp
@@ -0,0 +1,96 @@
+/*************************************************************************
+ * Copyright (C) 2008 Tavian Barnes <tavianator@gmail.com>               *
+ *                                                                       *
+ * This file is part of The Dimension Library.                           *
+ *                                                                       *
+ * The Dimension Library is free software; you can redistribute it and/  *
+ * or modify it under the terms of the GNU Lesser General Public License *
+ * as published by the Free Software Foundation; either version 3 of the *
+ * License, or (at your option) any later version.                       *
+ *                                                                       *
+ * The Dimension Library is distributed in the hope that it will be      *
+ * useful, but WITHOUT ANY WARRANTY; without even the implied warranty   *
+ * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU  *
+ * Lesser General Public License for more details.                       *
+ *                                                                       *
+ * You should have received a copy of the GNU Lesser General Public      *
+ * License along with this program.  If not, see                         *
+ * <http://www.gnu.org/licenses/>.                                       *
+ *************************************************************************/
+
+#include "dimensionxx.hpp"
+#include "../libdimension-png/dimension-png.h"
+
+namespace Dimension
+{
+  PNG_Canvas::~PNG_Canvas()
+  {
+    if (m_ostr && !m_written) {
+      try {
+        write();
+      } catch (...) {
+        dmnsn_error(DMNSN_SEVERITY_MEDIUM,
+                    "Writing canvas to PNG failed in PNG_Canvas destructor.");
+      }
+    }
+  }
+
+  void PNG_Canvas::write()
+  {
+    if (m_written) {
+      dmnsn_error(DMNSN_SEVERITY_MEDIUM,
+                  "Attempt to write canvas to PNG twice.");
+      return;
+    }
+
+    if (!m_ostr) {
+      dmnsn_error(DMNSN_SEVERITY_MEDIUM,
+                  "Attempt to write canvas to PNG without an output stream.");
+      return;
+    }      
+
+    FILE* file = fcookie(*m_ostr);
+    if (!file) {
+      dmnsn_error(DMNSN_SEVERITY_MEDIUM,
+                  "Couldn't create C++/C IO interface when writing canvas"
+                  " to PNG.");
+      return;
+    }      
+
+    if (dmnsn_png_write_canvas(m_canvas, file)) {
+      fclose(file);
+      dmnsn_error(DMNSN_SEVERITY_MEDIUM,
+                  "Writing canvas to PNG failed.");
+      return;
+    }
+
+    fclose(file);
+    m_written = true;
+  }
+
+  void PNG_Canvas::read()
+  {
+    if (!m_istr) {
+      dmnsn_error(DMNSN_SEVERITY_MEDIUM,
+                  "Attempt to read canvas from PNG without an input stream.");
+      return;
+    }      
+
+    FILE* file = fcookie(*m_istr);
+    if (!file) {
+      dmnsn_error(DMNSN_SEVERITY_MEDIUM,
+                  "Couldn't create C++/C IO interface when reading canvas"
+                  " from PNG.");
+      return;
+    }      
+
+    if (!(m_canvas = dmnsn_png_read_canvas(file))) {
+      fclose(file);
+      dmnsn_error(DMNSN_SEVERITY_MEDIUM,
+                  "Reading canvas from PNG failed.");
+      return;
+    }
+
+    fclose(file);
+  }
+}
diff --git a/tests/Makefile.am b/tests/Makefile.am
index f23b469..a11f18a 100644
--- a/tests/Makefile.am
+++ b/tests/Makefile.am
@@ -17,11 +17,11 @@
 ## along with this program.  If not, see <http://www.gnu.org/licenses/>. ##
 ###########################################################################
 
-check_PROGRAMS = warning error png
+check_PROGRAMS = warning error png pngxx
 TESTS          = $(check_PROGRAMS)
 XFAIL_TESTS    = error
 
-INCLUDES = -I../libdimension -I../libdimension-png
+INCLUDES = -I../libdimension -I../libdimension-png -I../libdimensionxx
 
 warning_SOURCES = warning.c
 warning_LDADD   = ../libdimension/libdimension.la
@@ -31,3 +31,6 @@ error_LDADD   = ../libdimension/libdimension.la
 
 png_SOURCES = png.c
 png_LDADD   = ../libdimension/libdimension.la ../libdimension-png/libdimension-png.la
+
+pngxx_SOURCES = pngxx.cpp
+pngxx_LDADD   = ../libdimensionxx/libdimensionxx.la
diff --git a/tests/png.c b/tests/png.c
index b7edd95..0ee7edb 100644
--- a/tests/png.c
+++ b/tests/png.c
@@ -33,7 +33,7 @@ int main() {
   dmnsn_sRGB sRGB;
   FILE *ofile, *ifile;
   unsigned int i, j;
-  const unsigned int x = 300, y = 300;
+  const unsigned int x = 333, y = 300;
 
   dmnsn_set_resilience(DMNSN_SEVERITY_LOW);
 
@@ -121,7 +121,7 @@ int main() {
     return EXIT_FAILURE;
   }
 
-  if (dmnsn_png_read_canvas(&canvas, ifile)) {
+  if (!(canvas = dmnsn_png_read_canvas(ifile))) {
     fprintf(stderr, "--- Reading canvas failed! ---\n");
     return EXIT_FAILURE;
   }
diff --git a/tests/pngxx b/tests/pngxx
new file mode 100755
index 0000000..436e7d8
--- /dev/null
+++ b/tests/pngxx
@@ -0,0 +1,148 @@
+#! /bin/sh
+
+# pngxx - temporary wrapper script for .libs/pngxx
+# Generated by ltmain.sh (GNU libtool) 2.2.6
+#
+# The pngxx program cannot be directly executed until all the libtool
+# libraries that it depends on are installed.
+#
+# This wrapper script should never be moved out of the build directory.
+# If it is, it will not operate correctly.
+
+# Sed substitution that helps us do robust quoting.  It backslashifies
+# metacharacters that are still active within double-quoted strings.
+Xsed='/bin/sed -e 1s/^X//'
+sed_quote_subst='s/\([`"$\\]\)/\\\1/g'
+
+# Be Bourne compatible
+if test -n "${ZSH_VERSION+set}" && (emulate sh) >/dev/null 2>&1; then
+  emulate sh
+  NULLCMD=:
+  # Zsh 3.x and 4.x performs word splitting on ${1+"$@"}, which
+  # is contrary to our usage.  Disable this feature.
+  alias -g '${1+"$@"}'='"$@"'
+  setopt NO_GLOB_SUBST
+else
+  case `(set -o) 2>/dev/null` in *posix*) set -o posix;; esac
+fi
+BIN_SH=xpg4; export BIN_SH # for Tru64
+DUALCASE=1; export DUALCASE # for MKS sh
+
+# The HP-UX ksh and POSIX shell print the target directory to stdout
+# if CDPATH is set.
+(unset CDPATH) >/dev/null 2>&1 && unset CDPATH
+
+relink_command="(cd /home/tavianator/dimension/tests; { test -z \"\${LIBRARY_PATH+set}\" || unset LIBRARY_PATH || { LIBRARY_PATH=; export LIBRARY_PATH; }; }; { test -z \"\${COMPILER_PATH+set}\" || unset COMPILER_PATH || { COMPILER_PATH=; export COMPILER_PATH; }; }; { test -z \"\${GCC_EXEC_PREFIX+set}\" || unset GCC_EXEC_PREFIX || { GCC_EXEC_PREFIX=; export GCC_EXEC_PREFIX; }; }; { test -z \"\${LD_RUN_PATH+set}\" || unset LD_RUN_PATH || { LD_RUN_PATH=; export LD_RUN_PATH; }; }; { test -z \"\${LD_LIBRARY_PATH+set}\" || unset LD_LIBRARY_PATH || { LD_LIBRARY_PATH=; export LD_LIBRARY_PATH; }; }; PATH=/bin:/usr/bin:/sbin:/usr/sbin:/usr/bin/perlbin/site:/usr/bin/perlbin/vendor:/usr/bin/perlbin/core:/opt/qt/bin; export PATH; g++ -g -O2 -o \$progdir/\$file pngxx.o  ../libdimensionxx/.libs/libdimensionxx.so /home/tavianator/dimension/libdimension/.libs/libdimension.so -lm -lpthread /home/tavianator/dimension/libdimension-png/.libs/libdimension-png.so -lpng -Wl,-rpath -Wl,/home/tavianator/dimension/libdimensionxx/.libs -Wl,-rpath -Wl,/home/tavianator/dimension/libdimension/.libs -Wl,-rpath -Wl,/home/tavianator/dimension/libdimension-png/.libs)"
+
+# This environment variable determines our operation mode.
+if test "$libtool_install_magic" = "%%%MAGIC variable%%%"; then
+  # install mode needs the following variables:
+  generated_by_libtool_version='2.2.6'
+  notinst_deplibs=' ../libdimensionxx/libdimensionxx.la /home/tavianator/dimension/libdimension/libdimension.la /home/tavianator/dimension/libdimension-png/libdimension-png.la'
+else
+  # When we are sourced in execute mode, $file and $ECHO are already set.
+  if test "$libtool_execute_magic" != "%%%MAGIC variable%%%"; then
+    ECHO="echo"
+    file="$0"
+    # Make sure echo works.
+    if test "X$1" = X--no-reexec; then
+      # Discard the --no-reexec flag, and continue.
+      shift
+    elif test "X`{ $ECHO '\t'; } 2>/dev/null`" = 'X\t'; then
+      # Yippee, $ECHO works!
+      :
+    else
+      # Restart under the correct shell, and then maybe $ECHO will work.
+      exec /bin/sh "$0" --no-reexec ${1+"$@"}
+    fi
+  fi
+
+  # Find the directory that this script lives in.
+  thisdir=`$ECHO "X$file" | $Xsed -e 's%/[^/]*$%%'`
+  test "x$thisdir" = "x$file" && thisdir=.
+
+  # Follow symbolic links until we get to the real thisdir.
+  file=`ls -ld "$file" | /bin/sed -n 's/.*-> //p'`
+  while test -n "$file"; do
+    destdir=`$ECHO "X$file" | $Xsed -e 's%/[^/]*$%%'`
+
+    # If there was a directory component, then change thisdir.
+    if test "x$destdir" != "x$file"; then
+      case "$destdir" in
+      [\\/]* | [A-Za-z]:[\\/]*) thisdir="$destdir" ;;
+      *) thisdir="$thisdir/$destdir" ;;
+      esac
+    fi
+
+    file=`$ECHO "X$file" | $Xsed -e 's%^.*/%%'`
+    file=`ls -ld "$thisdir/$file" | /bin/sed -n 's/.*-> //p'`
+  done
+
+
+  # Usually 'no', except on cygwin/mingw when embedded into
+  # the cwrapper.
+  WRAPPER_SCRIPT_BELONGS_IN_OBJDIR=no
+  if test "$WRAPPER_SCRIPT_BELONGS_IN_OBJDIR" = "yes"; then
+    # special case for '.'
+    if test "$thisdir" = "."; then
+      thisdir=`pwd`
+    fi
+    # remove .libs from thisdir
+    case "$thisdir" in
+    *[\\/].libs ) thisdir=`$ECHO "X$thisdir" | $Xsed -e 's%[\\/][^\\/]*$%%'` ;;
+    .libs )   thisdir=. ;;
+    esac
+  fi
+
+  # Try to get the absolute directory name.
+  absdir=`cd "$thisdir" && pwd`
+  test -n "$absdir" && thisdir="$absdir"
+
+  program=lt-'pngxx'
+  progdir="$thisdir/.libs"
+
+  if test ! -f "$progdir/$program" ||
+     { file=`ls -1dt "$progdir/$program" "$progdir/../$program" 2>/dev/null | /bin/sed 1q`; \
+       test "X$file" != "X$progdir/$program"; }; then
+
+    file="$$-$program"
+
+    if test ! -d "$progdir"; then
+      mkdir "$progdir"
+    else
+      rm -f "$progdir/$file"
+    fi
+
+    # relink executable if necessary
+    if test -n "$relink_command"; then
+      if relink_command_output=`eval $relink_command 2>&1`; then :
+      else
+	echo "$relink_command_output" >&2
+	rm -f "$progdir/$file"
+	exit 1
+      fi
+    fi
+
+    mv -f "$progdir/$file" "$progdir/$program" 2>/dev/null ||
+    { rm -f "$progdir/$program";
+      mv -f "$progdir/$file" "$progdir/$program"; }
+    rm -f "$progdir/$file"
+  fi
+
+  if test -f "$progdir/$program"; then
+    if test "$libtool_execute_magic" != "%%%MAGIC variable%%%"; then
+      # Run the actual program with our arguments.
+
+      exec "$progdir/$program" ${1+"$@"}
+
+      $ECHO "$0: cannot exec $program $*" 1>&2
+      exit 1
+    fi
+  else
+    # The program doesn't exist.
+    $ECHO "$0: error: \`$progdir/$program' does not exist" 1>&2
+    $ECHO "This script is just a wrapper for $program." 1>&2
+    echo "See the libtool documentation for more information." 1>&2
+    exit 1
+  fi
+fi
diff --git a/tests/pngxx.cpp b/tests/pngxx.cpp
new file mode 100644
index 0000000..ed7cffd
--- /dev/null
+++ b/tests/pngxx.cpp
@@ -0,0 +1,102 @@
+/*************************************************************************
+ * Copyright (C) 2008 Tavian Barnes <tavianator@gmail.com>               *
+ *                                                                       *
+ * This file is part of The Dimension Test Suite.                        *
+ *                                                                       *
+ * Dimension is free software; you can redistribute it and/or modify it  *
+ * under the terms of the GNU Lesser General Public License as published *
+ * by the Free Software Foundation; either version 3 of the License, or  *
+ * (at your option) any later version.                                   *
+ *                                                                       *
+ * Dimension is distributed in the hope that it will be useful, but      *
+ * WITHOUT ANY WARRANTY; without even the implied warranty of            *
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU     *
+ * Lesser General Public License for more details.                       *
+ *                                                                       *
+ * You should have received a copy of the GNU Lesser General Public      *
+ * License along with this program.  If not, see                         *
+ * <http://www.gnu.org/licenses/>.                                       *
+ *************************************************************************/
+
+#include "../libdimensionxx/dimensionxx.hpp"
+#include <fstream>
+
+int
+main()
+{
+  dmnsn_set_resilience(DMNSN_SEVERITY_LOW);
+
+  const unsigned int width = 333, height = 300;
+
+  {
+    std::ofstream ofstr("dimensionxx1.png", std::ios::binary);
+    Dimension::PNG_Canvas ocanvas(3*width, height, ofstr);
+
+    Dimension::CIE_xyY xyY;
+    Dimension::CIE_Lab Lab;
+    Dimension::CIE_Luv Luv;
+    Dimension::sRGB RGB;
+    Dimension::Color color;
+
+    for (unsigned int x = 0; x < width; ++x) {
+      for (unsigned int y = 0; y < height; ++y) {
+        /* CIE xyY colorspace */
+        xyY = Dimension::CIE_xyY(static_cast<double>(x)/(width - 1),
+                                 static_cast<double>(y)/(height - 1),
+                                 0.5);
+        color = xyY;
+        RGB = color;
+
+        if (RGB.R() > 1.0 || RGB.G() > 1.0 || RGB.B() > 1.0
+            || RGB.R() < 0.0 || RGB.G() < 0.0 || RGB.B() < 0.0) {
+          /* Out of sRGB gamut */
+          color.trans(0.5);
+        }
+
+        ocanvas.pixel(x, y, color);
+
+        /* CIE Lab colorspace */
+
+        Lab = Dimension::CIE_Lab(75.0,
+                                 200.0*(static_cast<double>(x)/
+                                        (width - 1) - 0.5),
+                                 200.0*(static_cast<double>(y)/
+                                        (height - 1) - 0.5));
+        color = Lab;
+        RGB = color;
+
+        if (RGB.R() > 1.0 || RGB.G() > 1.0 || RGB.B() > 1.0
+            || RGB.R() < 0.0 || RGB.G() < 0.0 || RGB.B() < 0.0) {
+          /* Out of sRGB gamut */
+          color.trans(0.5);
+        }
+
+        ocanvas.pixel(x + width, y, color);
+
+        /* CIE Luv colorspace */
+
+        Luv = Dimension::CIE_Luv(75.0,
+                                 200.0*(static_cast<double>(x)/
+                                        (width - 1) - 0.5),
+                                 200.0*(static_cast<double>(y)/
+                                        (height - 1) - 0.5));
+        color = Luv;
+        RGB = color;
+
+        if (RGB.R() > 1.0 || RGB.G() > 1.0 || RGB.B() > 1.0
+            || RGB.R() < 0.0 || RGB.G() < 0.0 || RGB.B() < 0.0) {
+          /* Out of sRGB gamut */
+          color.trans(0.5);
+        }
+
+        ocanvas.pixel(x + 2*width, y, color);
+      }
+    }
+  }
+
+  std::ifstream ifstr("dimensionxx1.png", std::ios::binary);
+  std::ofstream ofstr("dimensionxx2.png", std::ios::binary);
+  Dimension::PNG_Canvas iocanvas(ifstr, ofstr);
+
+  return 0;
+}