PNGGenerator.h

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//-*-c++-*-
#ifndef INCLUDED_PNGGenerator_h_
#define INCLUDED_PNGGenerator_h_

#include "Vision/FilterBankGenerator.h"
  
//! Generates FilterBankEvents containing PNG compressed images
/*!
 *  This class shares a lot of non-PNG specific code with JPEGGenerator,
 *  so you may want to replicate any changes made in that class as well.
 *
 *  @todo create a common super class with JPEGGenerator to hold common setup code
*/
class PNGGenerator : public FilterBankGenerator {
public:
  static const unsigned int PNG_HEADER_PAD=500; //!< add a bit to the expected size in getBinSize just to leave a little extra room for small images
  
  //! defines how to interpret the source images (see #srcMode and #curMode)
  enum src_mode_t {
    SRC_AUTO,       //!< if src is not a InterleavedYUVGenerator, SRC_GREYSCALE, otherwise SRC_COLOR
    SRC_GRAYSCALE,  //!< indicates each channel of source should be compressed individually as grayscale images
    SRC_COLOR       //!< indicates first channel should be in an interleaved layout which can be compressed into a "color" image
  };
  
  //! constructor
  PNGGenerator(unsigned int mysid, FilterBankGenerator* fbg, EventBase::EventTypeID_t tid);
  //! constructor
  PNGGenerator(unsigned int mysid, PNGGenerator::src_mode_t sMode, FilterBankGenerator* fbg, EventBase::EventTypeID_t tid);

  //! destructor
  virtual ~PNGGenerator();

  //! set #srcMode and #curMode as well if @a mode==SRC_AUTO
  virtual void setSourceMode(src_mode_t mode) { srcMode=mode; if(mode!=SRC_AUTO) curMode=mode;}
  //! returns #srcMode
  virtual src_mode_t getSourceMode() const { return srcMode; }
  //! returns #curMode
  virtual src_mode_t getCurrentSourceFormat() const { return curMode; }
  
  static std::string getClassDescription() { return "Compresses its source FilterBankGenerator's data into PNG format"; }
  
  //! should receive FilterBankEvents from a RawCameraGenerator (or a subclass thereof)
  virtual void doEvent();
  
  //! if we don't already know bytesUsed, let's assume the size will be smaller than the original uncompressed. If we fail this assumption, probably better to fail anyway.
  virtual unsigned int getBinSize() const;
  
  virtual unsigned int loadBuffer(const char buf[], unsigned int len, const char* filename=NULL);
  
  //! you probably don't want to be calling this to access the PNG -- use getImage() instead (saveBuffer will prepend some header information before the actual image data)
  virtual unsigned int saveBuffer(char buf[], unsigned int len) const;

  //! returns the number of bytes used for the image returned by getImage() - will return 0 if the image hasn't been calculated yet (so call it @e after getImage())
  virtual size_t getImageSize(unsigned int layer, unsigned int chan) const { return bytesUsed[layer][chan]; }
  
protected:
  virtual void setNumImages(unsigned int nLayers, unsigned int nChannels);
  virtual unsigned char * createImageCache(unsigned int layer, unsigned int chan) const;
  virtual void calcImage(unsigned int layer, unsigned int chan);
  virtual void destruct();
  
  src_mode_t srcMode;   //!< how to interpret source channel of next filter bank event
  src_mode_t curMode;   //!< how to interpret getImage's current image
  
  unsigned int ** bytesUsed; //!< number of bytes used per image to actually store data;
    
private:
  PNGGenerator(const PNGGenerator& fbk); //!< don't call
  const PNGGenerator& operator=(const PNGGenerator& fbk); //!< don't call
};

/*! @file
 * @brief Describes PNGGenerator, which generates FilterBankEvents containing PNG compressed images
 * @author Ethan Tira-Thompson (ejt) (Creator)
 */

#endif