///////////////////////////////////////////////////////////////////////////

//

// Copyright (c) 2014, Industrial Light & Magic, a division of Lucas

// Digital Ltd. LLC

// 

// All rights reserved.

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///////////////////////////////////////////////////////////////////////////

#ifndef INCLUDED_IMF_FLAT_IMAGE_CHANNEL_H

#define INCLUDED_IMF_FLAT_IMAGE_CHANNEL_H

//----------------------------------------------------------------------------

//

//      class FlatImageChannel,

//      template class TypedFlatImageChannel<T>

//

//      For an explanation of images, levels and channels,

//      see the comments in header file Image.h.

//

//----------------------------------------------------------------------------

#include <ImfImageChannel.h>

#include <ImfPixelType.h>

#include <ImfFrameBuffer.h>

#include <ImathBox.h>

#include <half.h>

OPENEXR_IMF_INTERNAL_NAMESPACE_HEADER_ENTER

class FlatImageLevel;

//

// Image channels:

//

// A TypedFlatImageChannel<T> holds the pixel data for a single channel

// of one level of a flat image.  The pixels in the channel are of type T,

// where T is either half, float or unsigned int.  Storage is allocated

// only for pixels within the data window of the level.

//

class FlatImageChannel: public ImageChannel

{

  public:

    //

    // Construct an OpenEXR frame buffer slice for this channel.

    // This function is needed reading an image from an OpenEXR

    // file and for saving an image in an OpenEXR file.

    // 

    virtual Slice           slice () const = 0;

    //

    // Access to the flat image level to which this channel belongs.

    //

    FlatImageLevel &        flatLevel ();

    const FlatImageLevel &  flatLevel () const;

  protected:

    friend class FlatImageLevel;

    FlatImageChannel (FlatImageLevel &level,

                      int xSampling,

                      int ySampling,

                      bool pLinear);

    virtual ~FlatImageChannel();

    virtual void            resize ();

    virtual void            resetBasePointer () = 0;

};

template <class T>

class TypedFlatImageChannel: public FlatImageChannel

{

  public:

    //

    // The OpenEXR pixel type of this channel (HALF, FLOAT or UINT).

    //

    virtual PixelType   pixelType () const;

    //

    // Construct an OpenEXR frame buffer slice for this channel.

    // 

    virtual Slice       slice () const;

    //

    // Access to the pixel at pixel space location (x, y), without

    // bounds checking.  Accessing a location outside the data window

    // of the image level results in undefined behavior.

    //

    T &                 operator () (int x, int y);

    const T &           operator () (int x, int y) const;

    //

    // Access to the pixel at pixel space location (x, y), with bounds

    // checking.  Accessing a location outside the data window of the

    // image level throws an Iex::ArgExc exception.

    //

    T &                 at (int x, int y);

    const T &           at (int x, int y) const;

    //

    // Faster access to all pixels in a single horizontal row of the

    // channel.  Rows are numbered from 0 to pixelsPerColumn()-1, and

    // each row contains pixelsPerRow() values.

    // Access is not bounds checked; accessing out of bounds rows or

    // pixels results in undefined behavior.

    //

    T *                 row (int r);

    const T *           row (int r) const;

  private:

    friend class FlatImageLevel;

    //

    // The constructor and destructor are not public because flat

    // image channels exist only as parts of a flat image level.

    //

    TypedFlatImageChannel (FlatImageLevel &level,

                           int xSampling,

                           int ySampling,

                           bool pLinear);

    virtual ~TypedFlatImageChannel ();

    virtual void        resize ();

    virtual void        resetBasePointer ();

    T *                 _pixels;        // Pointer to allocated storage

    T *                 _base;          // Base pointer for faster pixel access

};

//

// Channel typedefs for the pixel data types supported by OpenEXR.

//

typedef TypedFlatImageChannel<half>         FlatHalfChannel;

typedef TypedFlatImageChannel<float>        FlatFloatChannel;

typedef TypedFlatImageChannel<unsigned int> FlatUIntChannel;

//-----------------------------------------------------------------------------

// Implementation of templates and inline functions

//-----------------------------------------------------------------------------

template <class T>

TypedFlatImageChannel<T>::TypedFlatImageChannel

    (FlatImageLevel &level,

     int xSampling,

     int ySampling,

     bool pLinear)

:

    FlatImageChannel (level, xSampling, ySampling, pLinear),

    _pixels (0),

    _base (0)

{

    resize();

}

template <class T>

TypedFlatImageChannel<T>::~TypedFlatImageChannel ()

{

    delete [] _pixels;

}

template <>

inline PixelType

FlatHalfChannel::pixelType () const

{

    return HALF;

}

template <>

inline PixelType

FlatFloatChannel::pixelType () const

{

    return FLOAT;

}

template <>

inline PixelType

FlatUIntChannel::pixelType () const

{

    return UINT;

}

template <class T>

Slice

TypedFlatImageChannel<T>::slice () const

{

    return Slice (pixelType(),                 // type

                  (char *) _base,              // base

                  sizeof (T),                  // xStride

                  pixelsPerRow() * sizeof (T), // yStride

                  xSampling(),

                  ySampling());

}

template <class T>

inline T &

TypedFlatImageChannel<T>::operator () (int x, int y)

{

    return _base[(y / ySampling()) * pixelsPerRow() + (x / xSampling())];

}

template <class T>

inline const T &

TypedFlatImageChannel<T>::operator () (int x, int y) const

{

    return _base[(y / ySampling()) * pixelsPerRow() + (x / xSampling())];

}

template <class T>

inline T &

TypedFlatImageChannel<T>::at (int x, int y)

{

    boundsCheck (x, y);

    return _base[(y / ySampling()) * pixelsPerRow() + (x / xSampling())];

}

template <class T>

inline const T &

TypedFlatImageChannel<T>::at (int x, int y) const

{

    boundsCheck (x, y);

    return _base[(y / ySampling()) * pixelsPerRow() + (x / xSampling())];

}

template <class T>

inline T *

TypedFlatImageChannel<T>::row (int r)

{

    return _base + r * pixelsPerRow();

}

template <class T>

inline const T *

TypedFlatImageChannel<T>::row (int n) const

{

    return _base + n * pixelsPerRow();

}

template <class T>

void

TypedFlatImageChannel<T>::resize ()

{

    delete [] _pixels;

    _pixels = 0;

    FlatImageChannel::resize();  // may throw an exception

    _pixels = new T [numPixels()];

    for (size_t i = 0; i < numPixels(); ++i)

        _pixels[i] = T (0);

    resetBasePointer ();

}

template <class T>

void

TypedFlatImageChannel<T>::resetBasePointer ()

{

    _base = _pixels -

            (level().dataWindow().min.y / ySampling()) * pixelsPerRow() -

            (level().dataWindow().min.x / xSampling());

}

OPENEXR_IMF_INTERNAL_NAMESPACE_HEADER_EXIT

#endif