ossimPngCodec Class Reference

#include <ossimPngCodec.h>

Inheritance diagram for ossimPngCodec:

Public Member Functions
	ossimPngCodec (bool addAlpha=false)
virtual ossimString	getCodecType () const
	Will return the identifier used to identify the codec type. More...
virtual bool	encode (const ossimRefPtr< ossimImageData > &in, std::vector< ossim_uint8 > &out) const
	Encode png method. More...
virtual bool	decode (const std::vector< ossim_uint8 > &in, ossimRefPtr< ossimImageData > &out) const
	Decode png method. More...
virtual const std::string &	getExtension () const
virtual void	setProperty (ossimRefPtr< ossimProperty > property)
	Ineterface to allow for specific properties to be set. More...
virtual ossimRefPtr< ossimProperty >	getProperty (const ossimString &name) const
	Interface to get the value of a specific property. More...
virtual void	getPropertyNames (std::vector< ossimString > &propertyNames) const
	Get a list of all supported property names. More...
virtual bool	loadState (const ossimKeywordlist &kwl, const char *prefix=0)
	Allocate the state of the object thorugh a factory load/keywordlist. More...
virtual bool	saveState (ossimKeywordlist &kwl, const char *prefix=0) const
	Save the state of the codec to the keywordlist. More...
Public Member Functions inherited from ossimObject
	ossimObject ()
virtual	~ossimObject ()
virtual ossimObject *	dup () const
virtual ossimString	getShortName () const
virtual ossimString	getLongName () const
virtual ossimString	getDescription () const
virtual ossimString	getClassName () const
virtual RTTItypeid	getType () const
virtual bool	canCastTo (ossimObject *obj) const
virtual bool	canCastTo (const RTTItypeid &id) const
virtual bool	canCastTo (const ossimString &parentClassName) const
virtual std::ostream &	print (std::ostream &out) const
	Generic print method. More...
virtual bool	isEqualTo (const ossimObject &obj, ossimCompareType compareType=OSSIM_COMPARE_FULL) const
virtual void	accept (ossimVisitor &visitor)
Public Member Functions inherited from ossimReferenced
	ossimReferenced ()
	ossimReferenced (const ossimReferenced &)
ossimReferenced &	operator= (const ossimReferenced &)
void	ref () const
	increment the reference count by one, indicating that this object has another pointer which is referencing it. More...
void	unref () const
	decrement the reference count by one, indicating that a pointer to this object is referencing it. More...
void	unref_nodelete () const
	decrement the reference count by one, indicating that a pointer to this object is referencing it. More...
int	referenceCount () const
Public Member Functions inherited from ossimPropertyInterface
	ossimPropertyInterface ()
virtual	~ossimPropertyInterface ()
virtual void	setProperty (const ossimString &name, const ossimString &value)
virtual ossimString	getPropertyValueAsString (const ossimString &name) const
void	getPropertyList (std::vector< ossimRefPtr< ossimProperty > > &propertyList) const
void	setProperties (std::vector< ossimRefPtr< ossimProperty > > &propertyList)

Protected Attributes
bool	m_addAlphaChannel
std::string	m_ext

Additional Inherited Members
Protected Member Functions inherited from ossimReferenced
virtual	~ossimReferenced ()

Detailed Description

Definition at line 5 of file ossimPngCodec.h.

Constructor & Destructor Documentation

ossimPngCodec()

ossimPngCodec::ossimPngCodec

(

bool

addAlpha = false

)

Definition at line 28 of file ossimPngCodec.cpp.

   :m_addAlphaChannel(addAlpha),
    m_ext("png")
{

}

Member Function Documentation

decode()

bool ossimPngCodec::decode ( const std::vector< ossim_uint8 > &  in, ossimRefPtr< ossimImageData > &  out  ) const

virtual

Decode png method.

Parameters

in	Input data to decode.
out	Output tile. If the pointer to ossimImageData is null internally it will be created. For code loops it is better to pre initialized to correct size.

Note

Caller should set "out's" image rectangle upon successful decode.

Returns

true on success, false on failure.

Implements ossimCodecBase.

Definition at line 244 of file ossimPngCodec.cpp.

References y.

{
   bool result = true;
   ossim_uint32 y = 0;
   png_structp  pngPtr = 0;
   png_infop    infoPtr = 0;
   png_uint_32 pngWidth = 0;
   png_uint_32 pngHeight = 0;
   ossim_int32  pngBitDepth=0, pngByteDepth = 0, pngColorType=0, pngInterlaceType=0;

   // png_bytep* row_pointers=0;

   if (in.empty())
   {
      return false;
   }

   pngPtr = png_create_read_struct (PNG_LIBPNG_VER_STRING, 0, 0, 0);
   //assert (png_ptr && "creating png_create_write_structpng_create_write_struct failed");

   // Initialize info structure
   infoPtr = png_create_info_struct (pngPtr);

   // Setup Exception handling
   setjmp (png_jmpbuf(pngPtr));

   const ossim_uint8* inputPointer = &in.front();//&pngData_arg[0];
   png_set_read_fn (pngPtr, reinterpret_cast<void*> (&inputPointer), user_read_data);

   png_read_info (pngPtr, infoPtr);

   png_get_IHDR (pngPtr, infoPtr, &pngWidth, &pngHeight, &pngBitDepth,
                 &pngColorType, &pngInterlaceType, NULL, NULL);



   // ensure a color bit depth of 8
   //assert(png_bit_depth==sizeof(T)*8);

   ossim_uint32 pngChannels = 0;
   switch (pngColorType)
   {
      case PNG_COLOR_TYPE_GRAY:
      {
         pngChannels = 1;
         break;
      }
      case PNG_COLOR_TYPE_GRAY_ALPHA:
      {
         pngChannels = 2;
         break;     
      }
      case PNG_COLOR_TYPE_RGB:
      {
         pngChannels = 3;
         break;     
      }
      case PNG_COLOR_TYPE_RGB_ALPHA:
      {
         pngChannels = 4;
         break;     
      }
      default:
      {
         pngChannels = 0;
         break;     
      }
   }
   pngByteDepth = pngBitDepth>>3;
   //imageData_arg.clear ();
   //imageData_arg.resize (png_height * png_width * png_channels);

   ossim_uint32 bytes = pngHeight*pngWidth*pngChannels*pngByteDepth;
   //row_pointers = reinterpret_cast<png_bytep*> (malloc (sizeof(png_bytep) * png_height));
   std::vector<ossim_uint8> data(bytes);
   std::vector<ossim_uint8*> rowPointers(pngHeight);
   ossim_uint8* dataPtr = &data.front();
   for (y = 0; y < pngHeight; y++)
   {
      rowPointers[y] = reinterpret_cast<ossim_uint8*> (dataPtr + ( y*(pngWidth*pngByteDepth*pngChannels)));
   }

   png_read_image (pngPtr, &rowPointers.front());

   ossimScalarType scalarType = ((pngByteDepth==1)?OSSIM_UINT8:OSSIM_UINT16);
   ossim_uint32 bands = pngChannels;

   if((bands == 2) ||(bands==4))
   {
      bands = bands - 1;
   }
   // now allocate the ossimImageData object if not already allocated
   if(!out.valid())
   {
      out = new ossimImageData(0, scalarType, bands, pngWidth, pngHeight);
      out->initialize();
   }
   else
   {
      out->setNumberOfDataComponents(bands);
      out->setImageRectangleAndBands(ossimIrect(0,0,pngWidth-1,pngHeight-1), bands);
      out->initialize();
   }

   if(pngChannels == 1)
   {
      // ossim_uint32 idx = 0;
      memcpy(out->getBuf(0), dataPtr, bytes);
      out->validate();
      // once we support alpha channel properly we will need to add alpha settings here

   }
   else if(pngChannels == 2)
   {
      //std::cout << "DECODING 2 channels\n";
      ossim_uint32 size = pngWidth*pngHeight;
      ossim_uint32 idx = 0;
      if(scalarType == OSSIM_UINT16)
      {
         ossim_uint16* tempDataPtr = reinterpret_cast<ossim_uint16*> (dataPtr);
         ossim_uint16* buf = static_cast<ossim_uint16*>(out->getBuf(0));

         for(idx = 0; idx < size;++idx)
         {
            *buf = tempDataPtr[0];

            tempDataPtr+=2;++buf;
         }
         out->validate();
      }
      else if(scalarType == OSSIM_UINT8)
      {
         ossim_uint8* tempDataPtr = dataPtr;
         ossim_uint8* buf = static_cast<ossim_uint8*>(out->getBuf(0));

         for(idx = 0; idx < size;++idx)
         {
            *buf = *tempDataPtr;

            tempDataPtr+=2;++buf;
         }
         out->validate();
      }
      else
      {
         result = false;
      }
   }
   else if(pngChannels == 4)
   {
      //std::cout << "DECODING 4 channels\n";
      ossim_uint32 size = pngWidth*pngHeight;
      ossim_uint32 idx = 0;
      if(scalarType == OSSIM_UINT16)
      {
         ossim_uint16* tempDataPtr = reinterpret_cast<ossim_uint16*> (dataPtr);
         ossim_uint16* buf1 = static_cast<ossim_uint16*>(out->getBuf(0));
         ossim_uint16* buf2 = static_cast<ossim_uint16*>(out->getBuf(1));
         ossim_uint16* buf3 = static_cast<ossim_uint16*>(out->getBuf(2));

         for(idx = 0; idx < size;++idx)
         {
            *buf1 = tempDataPtr[0];
            *buf2 = tempDataPtr[1];
            *buf3 = tempDataPtr[2];

            tempDataPtr+=4;++buf1;++buf2;++buf3;
         }
         out->validate();
      }
      else if(scalarType == OSSIM_UINT8)
      {
         ossim_uint8* tempDataPtr = dataPtr;
         ossim_uint8* buf1 = static_cast<ossim_uint8*>(out->getBuf(0));
         ossim_uint8* buf2 = static_cast<ossim_uint8*>(out->getBuf(1));
         ossim_uint8* buf3 = static_cast<ossim_uint8*>(out->getBuf(2));

         for(idx = 0; idx < size;++idx)
         {
            *buf1 = tempDataPtr[0];
            *buf2 = tempDataPtr[1];
            *buf3 = tempDataPtr[2];

            tempDataPtr+=4;++buf1;++buf2;++buf3;
         }
         out->validate();
      }
      else
      {
         result = false;
      }
   }
   else
   {
      out->loadTile(dataPtr, out->getImageRectangle(), OSSIM_BIP);
   }

   if (infoPtr)
   {
      png_free_data (pngPtr, infoPtr, PNG_FREE_ALL, -1);
   }
   if (pngPtr)
   {
      png_destroy_read_struct (&pngPtr, 0, 0);
   }

   return result;
}

encode()

bool ossimPngCodec::encode ( const ossimRefPtr< ossimImageData > &  in, std::vector< ossim_uint8 > &  out  ) const

virtual

Encode png method.

Current options handled by this factory:

type: png

Parameters

in	Input data to encode.
out	Encoded output data.

Returns

true on success, false on failure.

Implements ossimCodecBase.

Definition at line 46 of file ossimPngCodec.cpp.

References ossimImageData::getBuf(), ossimImageData::getHeight(), ossimImageData::getNumberOfBands(), ossimRectilinearDataObject::getScalarType(), ossimImageData::getWidth(), m_addAlphaChannel, OSSIM_UINT16, OSSIM_UINT8, OSSIM_USHORT11, and y.

{
   out.clear();
   ossim_int32 colorType = -1;
   ossim_int32 bitDepth = 0;
   if(!in->getBuf()) return false;
   if(in->getNumberOfBands() == 1)
   {
      if(m_addAlphaChannel)
      {
         colorType = PNG_COLOR_TYPE_GRAY_ALPHA;
      }
      else
      {
         colorType = PNG_COLOR_TYPE_GRAY;
      }
   }
   else if(in->getNumberOfBands() == 3)
   {
      if(m_addAlphaChannel)
      {
         colorType = PNG_COLOR_TYPE_RGB_ALPHA;
      }
      else
      {
         colorType = PNG_COLOR_TYPE_RGB;
      }
   }
   if(colorType < 0) return false;

   switch(in->getScalarType())
   {
      case OSSIM_UINT8:
      {
         bitDepth = 8;
         break;
      }
      case OSSIM_USHORT11:
      case OSSIM_UINT16:
      {
         bitDepth = 16;
         break;
      }
      default:
      {
         bitDepth = 0;
      }
   }
   if(bitDepth == 0) return false;
   // std::cout << "bitDepth = " << bitDepth << ", BANDS = " << in->getNumberOfBands() << std::endl;
   ossim_int32 w = in->getWidth();
   ossim_int32 h = in->getHeight();
   png_structp p = png_create_write_struct(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL);
   TPngDestructor destroyPng(p);
   png_infop info_ptr = png_create_info_struct(p);
   setjmp(png_jmpbuf(p));

   png_set_IHDR(p, info_ptr, w, h, bitDepth,
                colorType,
                PNG_INTERLACE_NONE,
                PNG_COMPRESSION_TYPE_DEFAULT,
                PNG_FILTER_TYPE_DEFAULT);
   png_set_compression_level(p, 1);

   switch(colorType)
   {
      case PNG_COLOR_TYPE_GRAY:
      {
         if(bitDepth == 8)
         {
            ossim_uint8* buf = (ossim_uint8*)in->getBuf();
            std::vector<ossim_uint8*> rows(h);
            for(ossim_int32 y=0; y<h;++y)
            {
               rows[y] = (ossim_uint8*)(buf + y * w) ;          
            }
            png_set_rows(p, info_ptr, &rows[0]);
            png_set_write_fn(p, &out, PngWriteCallback, NULL);
            png_write_png(p, info_ptr, PNG_TRANSFORM_IDENTITY, NULL);
         }
         else if(bitDepth == 16)
         {
            ossim_uint16* buf = (ossim_uint16*)in->getBuf();
            std::vector<ossim_uint8*> rows(h);
            for(int y=0; y<h;++y)
            {
               rows[y] = (ossim_uint8*)(buf + y * w) ;          
            }
            png_set_rows(p, info_ptr, &rows[0]);
            png_set_write_fn(p, &out, PngWriteCallback, NULL);
            png_write_png(p, info_ptr, PNG_TRANSFORM_IDENTITY, NULL);
         }
         break;
      }
      case PNG_COLOR_TYPE_GRAY_ALPHA:
      {
         if(bitDepth == 8)
         {
            std::vector<ossim_uint8> buf(w*h*2);
            std::vector<ossim_uint8*> rows(h);
            ossim_uint8* bufPtr = &buf.front();
            in->unloadTileToBipAlpha(&buf.front(), in->getImageRectangle(), in->getImageRectangle());
            for(int y=0; y<h;++y)
            {
               rows[y] = (ossim_uint8*)(bufPtr + y * (w*2)) ;           
            }
            png_set_rows(p, info_ptr, &rows[0]);
            png_set_write_fn(p, &out, PngWriteCallback, NULL);
            png_write_png(p, info_ptr, PNG_TRANSFORM_IDENTITY, NULL);

         }
         else
         {
            std::vector<ossim_uint16> buf(w*h*2);
            std::vector<ossim_uint8*> rows(h);
            ossim_uint16* bufPtr = &buf.front();
            in->unloadTileToBipAlpha(&buf.front(), in->getImageRectangle(), in->getImageRectangle());
            for(ossim_int32 y=0; y<h;++y)
            {
               rows[y] = (ossim_uint8*)(bufPtr + y * (w*2)) ;           
            }
            png_set_rows(p, info_ptr, &rows[0]);
            png_set_write_fn(p, &out, PngWriteCallback, NULL);
            png_write_png(p, info_ptr, PNG_TRANSFORM_IDENTITY, NULL);
         }

         break;
      }
      case PNG_COLOR_TYPE_RGB:
      {
         if(bitDepth == 8)
         {
            std::vector<ossim_uint8> buf(w*h*3);
            std::vector<ossim_uint8*> rows(h);
            in->unloadTile(&buf.front(), in->getImageRectangle(), in->getImageRectangle(), OSSIM_BIP);
            ossim_uint8* bufPtr = &buf.front();
            for(ossim_int32 y=0; y<h;++y)
            {
               rows[y] = (ossim_uint8*)(bufPtr + y * (w*3)) ;           
            }
            png_set_rows(p, info_ptr, &rows[0]);
            png_set_write_fn(p, &out, PngWriteCallback, NULL);
            png_write_png(p, info_ptr, PNG_TRANSFORM_IDENTITY, NULL);
         }
         else
         {
            std::vector<ossim_uint16> buf(w*h*3);
            std::vector<ossim_uint8*> rows(h);
            ossim_uint16* bufPtr = &buf.front();
            in->unloadTile(&buf.front(), in->getImageRectangle(), in->getImageRectangle(),OSSIM_BIP);
            for(ossim_int32 y=0; y<h;++y)
            {
               rows[y] = (ossim_uint8*)(bufPtr + y * (w*3)) ;           
            }
            png_set_rows(p, info_ptr, &rows[0]);
            png_set_write_fn(p, &out, PngWriteCallback, NULL);
            png_write_png(p, info_ptr, PNG_TRANSFORM_IDENTITY, NULL);
         }
         break;
      }
      case PNG_COLOR_TYPE_RGB_ALPHA:
      {
         if(bitDepth == 8)
         {
            std::vector<ossim_uint8> buf(w*h*4);
            std::vector<ossim_uint8*> rows(h);
            in->unloadTileToBipAlpha(&buf.front(), in->getImageRectangle(), in->getImageRectangle());
            ossim_uint8* bufPtr = &buf.front();
            for(int y=0; y<h;++y)
            {
               rows[y] = (ossim_uint8*)(bufPtr + y * (w*4)) ;           
            }
            png_set_rows(p, info_ptr, &rows[0]);
            png_set_write_fn(p, &out, PngWriteCallback, NULL);
            png_write_png(p, info_ptr, PNG_TRANSFORM_IDENTITY, NULL);
         }
         else
         {
            std::vector<ossim_uint16> buf(w*h*4);
            std::vector<ossim_uint8*> rows(h);
            in->unloadTileToBipAlpha(&buf.front(), in->getImageRectangle(), in->getImageRectangle());
            ossim_uint16* bufPtr = &buf.front();
            for(ossim_int32 y=0; y<h;++y)
            {
               rows[y] = (ossim_uint8*)(bufPtr + y * (w*4)) ;           
            }
            png_set_rows(p, info_ptr, &rows[0]);
            png_set_write_fn(p, &out, PngWriteCallback, NULL);
            png_write_png(p, info_ptr, PNG_TRANSFORM_IDENTITY, NULL);
         }
         break;
      }
   }

   return true;
}

getCodecType()

ossimString ossimPngCodec::getCodecType ( ) const

virtual

Will return the identifier used to identify the codec type.

For example the Jpeg codec will have "jpeg" as the identifier

Returns

Codec identifier

Implements ossimCodecBase.

Definition at line 35 of file ossimPngCodec.cpp.

{
   return "png";
}

getExtension()

const std::string & ossimPngCodec::getExtension ( ) const

virtual

Implements ossimCodecBase.

Definition at line 40 of file ossimPngCodec.cpp.

References m_ext.

{
   return m_ext; // "png"
}

getProperty()

ossimRefPtr< ossimProperty > ossimPngCodec::getProperty ( const ossimString &  name ) const

virtual

Interface to get the value of a specific property.

Parameters

in	name. Property name to retrieve

Returns

property value

Reimplemented from ossimPropertyInterface.

Definition at line 466 of file ossimPngCodec.cpp.

{
   ossimRefPtr<ossimProperty> result;

   if(name == ADD_ALPHA_CHANNEL_KW)
   {

   }
   else
   {
      result = ossimCodecBase::getProperty(name);
   }

   return result;
}

getPropertyNames()

void ossimPngCodec::getPropertyNames ( std::vector< ossimString > &  propertyNames ) const

virtual

Get a list of all supported property names.

Currently only "quality" property is exposed

Parameters

out	proeprtyNames. push the list of proeprty names to the list

Reimplemented from ossimPropertyInterface.

Definition at line 482 of file ossimPngCodec.cpp.

{
   propertyNames.push_back(ADD_ALPHA_CHANNEL_KW);
}

loadState()

bool ossimPngCodec::loadState ( const ossimKeywordlist &  kwl, const char *  prefix = 0  )

virtual

Allocate the state of the object thorugh a factory load/keywordlist.

Parameters

in	kwl. Input keywordlist that holds the values.
in	prefix. prefix to use for all keywords.

Reimplemented from ossimObject.

Definition at line 487 of file ossimPngCodec.cpp.

References ossimKeywordlist::find().

{
   ossimString addAlphaChannel = kwl.find(prefix, ADD_ALPHA_CHANNEL_KW);

   if(!addAlphaChannel.empty())
   {
      m_addAlphaChannel = addAlphaChannel.toBool();
   }

   return ossimCodecBase::loadState(kwl, prefix);
}

saveState()

bool ossimPngCodec::saveState ( ossimKeywordlist &  kwl, const char *  prefix = 0  ) const

virtual

Save the state of the codec to the keywordlist.

Parameters

out	kwl. Input keywordlist that holds the values.
in	prefix. prefix to use for all keywords.

Reimplemented from ossimObject.

Definition at line 499 of file ossimPngCodec.cpp.

References ossimKeywordlist::add().

{
   kwl.add(prefix, ADD_ALPHA_CHANNEL_KW, m_addAlphaChannel);

   return ossimCodecBase::saveState(kwl, prefix);
}

setProperty()

void ossimPngCodec::setProperty ( ossimRefPtr< ossimProperty >  property )

virtual

Ineterface to allow for specific properties to be set.

Reimplemented from ossimPropertyInterface.

Definition at line 454 of file ossimPngCodec.cpp.

References ossimProperty::getName().

{
   if(property->getName() == ADD_ALPHA_CHANNEL_KW)
   {
      m_addAlphaChannel = property->valueToString().toBool();
   }
   else
   {
      ossimCodecBase::setProperty(property);
   }
}

Member Data Documentation

m_addAlphaChannel

bool ossimPngCodec::m_addAlphaChannel

protected

Definition at line 90 of file ossimPngCodec.h.

Referenced by encode().

m_ext

std::string ossimPngCodec::m_ext

protected

Definition at line 91 of file ossimPngCodec.h.

Referenced by getExtension().

---

The documentation for this class was generated from the following files:

• ossimPngCodec.h
• ossimPngCodec.cpp