--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/Core/PngWriter.cpp	Thu Jul 19 14:32:22 2012 +0200
@@ -0,0 +1,235 @@
+/**
+ * Palantir - A Lightweight, RESTful DICOM Store
+ * Copyright (C) 2012 Medical Physics Department, CHU of Liege,
+ * Belgium
+ *
+ * This program is free software: you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ * 
+ * This program 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
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ **/
+
+
+#include "PngWriter.h"
+
+#include <vector>
+#include <stdint.h>
+#include <png.h>
+#include "PalantirException.h"
+#include "ChunkedBuffer.h"
+
+
+// http://www.libpng.org/pub/png/libpng-1.2.5-manual.html#section-4
+// http://zarb.org/~gc/html/libpng.html
+/*
+  void write_row_callback(png_ptr, png_uint_32 row, int pass)
+  {
+  }*/
+
+
+
+
+/*  bool isError_;
+
+// http://www.libpng.org/pub/png/book/chapter14.html#png.ch14.div.2
+
+static void ErrorHandler(png_structp png, png_const_charp message)
+{
+printf("** [%s]\n", message);
+
+PngWriter* that = (PngWriter*) png_get_error_ptr(png);
+that->isError_ = true;
+printf("** %d\n", (int)that);
+
+//((PngWriter*) payload)->isError_ = true;
+}
+
+static void WarningHandler(png_structp png, png_const_charp message)
+{
+  printf("++ %d\n", (int)message);
+}*/
+
+
+namespace Palantir
+{
+  struct PngWriter::PImpl
+  {
+    png_structp png_;
+    png_infop info_;
+
+    // Filled by Prepare()
+    std::vector<uint8_t*> rows_;
+    int bitDepth_;
+    int colorType_;
+  };
+
+
+
+  PngWriter::PngWriter() : pimpl_(new PImpl)
+  {
+    pimpl_->png_ = NULL;
+    pimpl_->info_ = NULL;
+
+    pimpl_->png_ = png_create_write_struct
+      (PNG_LIBPNG_VER_STRING, NULL, NULL, NULL); //this, ErrorHandler, WarningHandler);
+    if (!pimpl_->png_)
+    {
+      throw PalantirException(ErrorCode_NotEnoughMemory);
+    }
+
+    pimpl_->info_ = png_create_info_struct(pimpl_->png_);
+    if (!pimpl_->info_)
+    {
+      png_destroy_write_struct(&pimpl_->png_, NULL);
+      throw PalantirException(ErrorCode_NotEnoughMemory);
+    }
+  }
+
+  PngWriter::~PngWriter()
+  {
+    if (pimpl_->info_)
+    {
+      png_destroy_info_struct(pimpl_->png_, &pimpl_->info_);
+    }
+
+    if (pimpl_->png_)
+    {
+      png_destroy_write_struct(&pimpl_->png_, NULL);
+    }
+  }
+
+
+
+  void PngWriter::Prepare(unsigned int width,
+                          unsigned int height,
+                          unsigned int pitch,
+                          PixelFormat format,
+                          const void* buffer)
+  {
+    pimpl_->rows_.resize(height);
+    for (unsigned int y = 0; y < height; y++)
+    {
+      pimpl_->rows_[y] = const_cast<uint8_t*>(reinterpret_cast<const uint8_t*>(buffer)) + y * pitch;
+    }
+
+    switch (format)
+    {
+    case PixelFormat_Grayscale8:
+      pimpl_->bitDepth_ = 8;
+      pimpl_->colorType_ = PNG_COLOR_TYPE_GRAY;
+      break;
+
+    case PixelFormat_Grayscale16:
+      pimpl_->bitDepth_ = 16;
+      pimpl_->colorType_ = PNG_COLOR_TYPE_GRAY;
+      break;
+
+    default:
+      throw PalantirException(ErrorCode_NotImplemented);
+    }
+  }
+
+
+  void PngWriter::Compress(unsigned int width,
+                           unsigned int height,
+                           unsigned int pitch,
+                           PixelFormat format)
+  {
+    png_set_IHDR(pimpl_->png_, pimpl_->info_, width, height,
+                 pimpl_->bitDepth_, pimpl_->colorType_, PNG_INTERLACE_NONE,
+                 PNG_COMPRESSION_TYPE_BASE, PNG_FILTER_TYPE_BASE);
+
+    png_write_info(pimpl_->png_, pimpl_->info_);
+
+    if (height > 0)
+    {
+      switch (format)
+      {
+      case PixelFormat_Grayscale16:
+        // Must swap the endianness!!
+        png_set_rows(pimpl_->png_, pimpl_->info_, &pimpl_->rows_[0]);
+        png_write_png(pimpl_->png_, pimpl_->info_, PNG_TRANSFORM_SWAP_ENDIAN, NULL);
+        break;
+
+      default:
+        png_write_image(pimpl_->png_, &pimpl_->rows_[0]);
+      }
+    }
+
+    png_write_end(pimpl_->png_, NULL);
+  }
+
+
+  void PngWriter::WriteToFile(const char* filename,
+                              unsigned int width,
+                              unsigned int height,
+                              unsigned int pitch,
+                              PixelFormat format,
+                              const void* buffer)
+  {
+    Prepare(width, height, pitch, format, buffer);
+
+    FILE* fp = fopen(filename, "wb");
+    if (!fp)
+    {
+      throw PalantirException(ErrorCode_CannotWriteFile);
+    }    
+
+    png_init_io(pimpl_->png_, fp);
+
+    if (setjmp(png_jmpbuf(pimpl_->png_)))
+    {
+      // Error during writing PNG
+      throw PalantirException(ErrorCode_CannotWriteFile);      
+    }
+
+    Compress(width, height, pitch, format);
+
+    fclose(fp);
+  }
+
+
+
+
+  static void MemoryCallback(png_structp png_ptr, 
+                             png_bytep data, 
+                             png_size_t size)
+  {
+    ChunkedBuffer* buffer = (ChunkedBuffer*) png_get_io_ptr(png_ptr);
+    buffer->AddChunk(reinterpret_cast<const char*>(data), size);
+  }
+
+
+
+  void PngWriter::WriteToMemory(std::string& png,
+                                unsigned int width,
+                                unsigned int height,
+                                unsigned int pitch,
+                                PixelFormat format,
+                                const void* buffer)
+  {
+    ChunkedBuffer chunks;
+
+    Prepare(width, height, pitch, format, buffer);
+
+    if (setjmp(png_jmpbuf(pimpl_->png_)))
+    {
+      // Error during writing PNG
+      throw PalantirException(ErrorCode_InternalError);      
+    }
+
+    png_set_write_fn(pimpl_->png_, &chunks, MemoryCallback, NULL);
+
+    Compress(width, height, pitch, format);
+
+    chunks.Flatten(png);
+  }
+}