ossimPngReader.h

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//----------------------------------------------------------------------------
//
// License:  LGPL
// 
// See LICENSE.txt file in the top level directory for more details.
//
// Author:  David Burken
//
// Description: OSSIM Portable Network Graphics (PNG) reader (tile source).
//
//----------------------------------------------------------------------------
// $Id: ossimPngReader.h 23355 2015-06-01 23:55:15Z dburken $
#ifndef ossimPngReader_HEADER
#define ossimPngReader_HEADER 1

#include <ossim/imaging/ossimImageHandler.h>
#include <ossim/imaging/ossimStreamReaderInterface.h>
#include <ossim/imaging/ossimAppFixedTileCache.h>
#include <ossim/base/ossimIosFwd.h>
#include <png.h>
#include <memory>
#include <vector>

class ossimImageData;

class ossimPngReader : public ossimImageHandler, public ossimStreamReaderInterface
{
public:

   enum ossimPngReadMode
   {
      ossimPngReadUnknown = 0,
      ossimPngRead8       = 1,
      ossimPngRead16      = 2,
      ossimPngRead8a      = 3,
      ossimPngRead16a     = 4 
   };

   ossimPngReader();

   virtual ~ossimPngReader();

   virtual ossimString getShortName() const;

   virtual ossimString getLongName()  const;

   virtual ossimString getClassName()    const;

   virtual ossimRefPtr<ossimImageData> getTile(const  ossimIrect& rect,
                                               ossim_uint32 resLevel=0);
   virtual bool getTile(ossimImageData* result, ossim_uint32 resLevel=0);

   virtual ossim_uint32 getNumberOfInputBands() const;

   virtual ossim_uint32 getNumberOfOutputBands()const;

   virtual ossim_uint32 getNumberOfLines(ossim_uint32 reduced_res_level = 0) const;

   virtual ossim_uint32 getNumberOfSamples(ossim_uint32 reduced_res_level = 0) const;

   virtual ossimIrect getImageRectangle(ossim_uint32 reduced_res_level = 0) const;

   virtual bool saveState(ossimKeywordlist& kwl,
                          const char* prefix=0)const;

   virtual bool loadState(const ossimKeywordlist& kwl,
                          const char* prefix=0);

   virtual void setProperty(ossimRefPtr<ossimProperty> property);

   virtual ossimRefPtr<ossimProperty> getProperty(const ossimString& name) const;
   
   virtual void getPropertyNames(std::vector<ossimString>& propertyNames) const;

   virtual ossimScalarType getOutputScalarType() const;

   virtual ossim_uint32    getTileWidth() const;

   virtual ossim_uint32    getTileHeight() const;

   virtual ossim_uint32 getImageTileWidth() const;

   virtual ossim_uint32 getImageTileHeight() const;

   bool isOpen()const;

   virtual double getMaxPixelValue(ossim_uint32 band = 0)const;

   virtual bool open( std::shared_ptr<ossim::istream>& str,
                      const std::string& connectionString );

   virtual void close();

   bool checkSignature(std::istream& str);

   virtual ossimRefPtr<ossimImageGeometry> getImageGeometry();
   
protected:

   bool open( std::shared_ptr<ossim::istream>& str );
   
   bool readPngInit();

   bool initReader();
   
   void readPngVersionInfo();
   ossimString getPngColorTypeString() const;

   void setMaxPixelValue();

   virtual bool open();

   void allocate();

   void destroy();

   void restart();

   void fillTile(const ossimIrect& clip_rect, ossimImageData* tile);

   template <class T> void copyLines(T dummy,  ossim_uint32 stopLine);
   template <class T> void copyLinesWithAlpha(T, ossim_uint32 stopLine);

   static void pngReadData(
      png_structp png_ptr, png_bytep data, png_size_t length);

   ossimRefPtr<ossimImageData>  m_tile;
   ossimRefPtr<ossimImageData>  m_cacheTile;

   ossim_uint8*  m_lineBuffer;
   ossim_uint32  m_lineBufferSizeInBytes;

   std::shared_ptr<ossim::istream> m_str;
   
   ossimIrect    m_bufferRect;
   ossimIrect    m_imageRect;
   ossim_uint32  m_numberOfInputBands;
   ossim_uint32  m_numberOfOutputBands;
   ossim_uint32  m_bytePerPixelPerBand;
   ossimIpt      m_cacheSize;


   ossimAppFixedTileCache::ossimAppFixedCacheId m_cacheId;

   png_structp      m_pngReadPtr;
   png_infop        m_pngReadInfoPtr;
   ossim_int8       m_pngColorType;
   ossim_uint32     m_currentRow; // 0 at start or first line
   ossimScalarType  m_outputScalarType;
   ossim_int32      m_interlacePasses;
   ossim_int8       m_bitDepth;
   ossimPngReadMode m_readMode;

   std::vector<ossim_float64> m_maxPixelValue;

   bool m_swapFlag;

   // If true the alpha channel will be passed on as a band.
   bool m_useAlphaChannelFlag;
   
TYPE_DATA
};

#endif /* #ifndef ossimPngReader_HEADER */