ImfOutputFile.h

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//
// SPDX-License-Identifier: BSD-3-Clause
// Copyright (c) Contributors to the OpenEXR Project.
//


#ifndef INCLUDED_IMF_OUTPUT_FILE_H
#define INCLUDED_IMF_OUTPUT_FILE_H

//-----------------------------------------------------------------------------
//
//      class OutputFile
//
//-----------------------------------------------------------------------------

#include "ImfForward.h"

#include "ImfGenericOutputFile.h"
#include "ImfThreading.h"


OPENEXR_IMF_INTERNAL_NAMESPACE_HEADER_ENTER


class IMF_EXPORT_TYPE OutputFile : public GenericOutputFile
{
  public:

    //-----------------------------------------------------------
    // Constructor -- opens the file and writes the file header.
    // The file header is also copied into the OutputFile object,
    // and can later be accessed via the header() method.
    // Destroying this OutputFile object automatically closes
    // the file.
    //
    // numThreads determines the number of threads that will be
    // used to write the file (see ImfThreading.h).
    //-----------------------------------------------------------

    IMF_EXPORT
    OutputFile (const char fileName[], const Header &header,
                int numThreads = globalThreadCount());


    //------------------------------------------------------------
    // Constructor -- attaches the new OutputFile object to a file
    // that has already been opened, and writes the file header.
    // The file header is also copied into the OutputFile object,
    // and can later be accessed via the header() method.
    // Destroying this OutputFile object does not automatically
    // close the file.
    //
    // numThreads determines the number of threads that will be
    // used to write the file (see ImfThreading.h).
    //------------------------------------------------------------

    IMF_EXPORT
    OutputFile (OPENEXR_IMF_INTERNAL_NAMESPACE::OStream &os, const Header &header,
                int numThreads = globalThreadCount());


    //-------------------------------------------------
    // Destructor
    //
    // Destroying the OutputFile object before writing
    // all scan lines within the data window results in
    // an incomplete file.
    //-------------------------------------------------

    IMF_EXPORT
    virtual ~OutputFile ();


    //------------------------
    // Access to the file name
    //------------------------

    IMF_EXPORT
    const char *        fileName () const;


    //--------------------------
    // Access to the file header
    //--------------------------

    IMF_EXPORT
    const Header &      header () const;


    //-------------------------------------------------------
    // Set the current frame buffer -- copies the FrameBuffer
    // object into the OutputFile object.
    //
    // The current frame buffer is the source of the pixel
    // data written to the file.  The current frame buffer
    // must be set at least once before writePixels() is
    // called.  The current frame buffer can be changed
    // after each call to writePixels.
    //-------------------------------------------------------

    IMF_EXPORT
    void                setFrameBuffer (const FrameBuffer &frameBuffer);


    //-----------------------------------
    // Access to the current frame buffer
    //-----------------------------------

    IMF_EXPORT
    const FrameBuffer & frameBuffer () const;


    //-------------------------------------------------------------------
    // Write pixel data:
    //
    // writePixels(n) retrieves the next n scan lines worth of data from
    // the current frame buffer, starting with the scan line indicated by
    // currentScanLine(), and stores the data in the output file, and
    // progressing in the direction indicated by header.lineOrder().
    //
    // To produce a complete and correct file, exactly m scan lines must
    // be written, where m is equal to
    // header().dataWindow().max.y - header().dataWindow().min.y + 1.
    //-------------------------------------------------------------------

    IMF_EXPORT
    void                writePixels (int numScanLines = 1);


    //------------------------------------------------------------------
    // Access to the current scan line:
    //
    // currentScanLine() returns the y coordinate of the first scan line
    // that will be read from the current frame buffer during the next
    // call to writePixels().
    //
    // If header.lineOrder() == INCREASING_Y:
    //
    //  The current scan line before the first call to writePixels()
    //  is header().dataWindow().min.y.  After writing each scan line,
    //  the current scan line is incremented by 1.
    //
    // If header.lineOrder() == DECREASING_Y:
    //
    //  The current scan line before the first call to writePixels()
    //  is header().dataWindow().max.y.  After writing each scan line,
    //  the current scan line is decremented by 1.
    //
    //------------------------------------------------------------------

    IMF_EXPORT
    int                 currentScanLine () const;


    //--------------------------------------------------------------
    // Shortcut to copy all pixels from an InputFile into this file,
    // without uncompressing and then recompressing the pixel data.
    // This file's header must be compatible with the InputFile's
    // header:  The two header's "dataWindow", "compression",
    // "lineOrder" and "channels" attributes must be the same.
    //--------------------------------------------------------------

    IMF_EXPORT
    void                copyPixels (InputFile &in);
    
    //-------------------------------------------------------------
    // Shortcut to copy all pixels from an InputPart into this file
    // - equivalent to copyPixel(InputFile &in) but for multipart files
    //---------------------------------------------------------------
    
    IMF_EXPORT
    void                copyPixels (InputPart &in);
        


    //--------------------------------------------------------------
    // Updating the preview image:
    //
    // updatePreviewImage() supplies a new set of pixels for the
    // preview image attribute in the file's header.  If the header
    // does not contain a preview image, updatePreviewImage() throws
    // an IEX_NAMESPACE::LogicExc.
    //
    // Note: updatePreviewImage() is necessary because images are
    // often stored in a file incrementally, a few scan lines at a
    // time, while the image is being generated.  Since the preview
    // image is an attribute in the file's header, it gets stored in
    // the file as soon as the file is opened, but we may not know
    // what the preview image should look like until we have written
    // the last scan line of the main image.
    //
    //--------------------------------------------------------------

    IMF_EXPORT
    void                updatePreviewImage (const PreviewRgba newPixels[]);


    //---------------------------------------------------------
    // Break a scan line -- for testing and debugging only:
    // 
    // breakScanLine(y,p,n,c) introduces an error into the
    // output file by writing n copies of character c, starting
    // p bytes from the beginning of the pixel data block that
    // contains scan line y.
    //
    // Warning: Calling this function usually results in a
    // broken image file.  The file or parts of it may not
    // be readable, or the file may contain bad data.
    //
    //---------------------------------------------------------

    IMF_EXPORT
    void                breakScanLine  (int y, int offset, int length, char c);


    struct IMF_HIDDEN Data;

  private:

    //------------------------------------------------------------
    // Constructor -- attaches the OutputStreamMutex to the
    // given one from MultiPartOutputFile. Set the previewPosition
    // and lineOffsetsPosition which have been acquired from
    // the constructor of MultiPartOutputFile as well.
    //------------------------------------------------------------
    IMF_HIDDEN OutputFile (const OutputPartData* part);

    OutputFile (const OutputFile &) = delete;
    OutputFile & operator = (const OutputFile &) = delete;
    OutputFile (OutputFile &&) = delete;
    OutputFile & operator = (OutputFile &&) = delete;

    void                initialize (const Header &header);

    Data *              _data;


    friend class MultiPartOutputFile;
    
};


OPENEXR_IMF_INTERNAL_NAMESPACE_HEADER_EXIT


#endif