multi_impex.hxx

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/*               Copyright 2003 by Gunnar Kedenburg                     */
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#ifndef VIGRA_MULTI_IMPEX_HXX
#define VIGRA_MULTI_IMPEX_HXX

#include <memory>
#include <iomanip>
#include <sstream>
#include <iostream>
#include <string>
#include <fstream>

#include "config.hxx"
#include "basicimageview.hxx"
#include "impex.hxx"
#include "multi_array.hxx"
#include "multi_pointoperators.hxx"
#include "sifImport.hxx"

#ifdef _MSC_VER
# include <direct.h>
#else
# include <unistd.h>
#endif

namespace vigra {

/** \addtogroup VolumeImpex Import/export of volume data.
*/

//@{

/** \brief Argument object for the function importVolume().

    This object can be used to define the properties of a volume
    data set to be read from disk. It works like \ref vigra::ImageImportInfo,
    but for 3-dimensional data. See \ref importVolume() for usage example.

    <b>\#include</b> <vigra/multi_impex.hxx> <br/>
    Namespace: vigra
**/
class VolumeImportInfo
{
  public:
    typedef ImageImportInfo::PixelType PixelType;

        /// type of volume size returned by shape()
    typedef MultiArrayShape<3>::type   ShapeType;

        /// type of volume size returned by shape()
    typedef ShapeType                  size_type;

        /// 3D resolution type returned by resolution()
    typedef TinyVector<float, 3>       Resolution;

        /** Construct VolumeImportInfo from a single filename.

            The \a filename (which may contain a path) can be interpreted in three different ways:
            <ul>
            <li>If the name refers to a file that contains volume data, the header information
                of this file is read. Two file formats are currently supported: Andor .SIF
                and multi-page TIFF.
            <li>If the name refers to a textfile, the constructor will attempt to interpret the file
                in the ".info" format to obtain the header information. The volume data
                are then expected to be located in an accompanying RAW file. The ".info" file must
                contain the following key-value pairs:
                <UL>
                <LI> name = [short descriptive name of the volume] (optional)
                <LI> filename = [absolute or relative path to raw voxel data file] (required)
                <li> description =  [arbitrary description of the data set] (optional)
                <li> width = [positive integer] (required)
                <li> height = [positive integer] (required)
                <li> depth = [positive integer] (required)
                <li> datatype = [ UINT8 | INT16 | UINT16 | INT32 | UINT32 | FLOAT | DOUBLE ] (required)
                </UL>
                Lines starting with "#" are ignored. To read the data correctly, the
                value_type of the target MultiArray must match the datatype stored in the file.
                Only single-band files are currently supported.
            <li>If the name refers to a 2D image file, the constructor will attempt to decompose
                the filename into the format <tt>base_name + slice_number + name_extension</tt>.
                If this decomposition succeeds, all images with the same base_name and name_extension
                will be considered as the slices of an image stack. Slice numbers need not be consecutive
                (i.e. gaps are allowed) and will be interpreted according to their numerical order
                (i.e. "009", "010", "011" are read in the same order as "9", "10", "11"). The number of images
                found determines the depth of the volume, the remaining header data are read from the given image.
            </ul>
         */
    VIGRA_EXPORT VolumeImportInfo(const std::string &filename);

        /** Construct VolumeImportInfo for a stack of images.

            The constructor will look for filenames of the form <tt>base_name + slice_number + name_extension</tt>.
            All images conforming to this pattern will be considered as the slices of an image stack.
            Slice numbers need not be consecutive (i.e. gaps are allowed) and will be interpreted according
            to their numerical order (i.e. "009", "010", "011" are read in the same order as "9", "10", "11").
            The number of images found determines the depth of the volume, the remaining header data are read
            from the given image. \a name_base may contain a path.
         */
    VIGRA_EXPORT VolumeImportInfo(const std::string &base_name, const std::string &name_extension);

        /** Get the shape of the volume.
         */
    VIGRA_EXPORT ShapeType shape() const;

        /** Get width of the volume.
         **/
    VIGRA_EXPORT MultiArrayIndex width() const;

        /** Get height of the volume.
         **/
    VIGRA_EXPORT MultiArrayIndex height() const;

        /** Get depth of the volume.
         **/
    VIGRA_EXPORT MultiArrayIndex depth() const;

        /**
         * resolution() contains the alignment and resolution of the
         * volume.  resolution()[0] is the x increment in a left-handed
         * world coordinate system of one unstrided step in the volume
         * memory.  The [1] and [2] elements contain the y resp. z
         * increments of the strided row resp. slice steps in the
         * volume.
         *
         * EXAMPLES: (1.f, 1.f, 4.f) means that the slices are four
         * times thicker than the x/y resolution.
         * (1.f, -1.f, 1.f) means that the volume coordinate system is
         * right-handed.
         */
    VIGRA_EXPORT Resolution resolution() const;

        /** Query the file type.

            Possible values are:
            <DL>
            <DT>"MULTIPAGE"<DD> Multiple 2D images in a single file (currently only supported by TIFF).
            <DT>"SIF"<DD>  <a href="http://www.andor.com">Andor Technology's</a> .sif format.
            <DT>"RAW"<DD> Raw data file, accompanied by a .info file
            <DT>"STACK"<DD> A numbered set of 2D image files, one per slice of the volume.
            </DL>
         **/
    VIGRA_EXPORT const char * getFileType() const;

        /** Query the pixel type of the volume data.

            Possible values are:
            <DL>
            <DT>"INT8"<DD> 8-bit signed integer (signed char)
            <DT>"UINT8"<DD> 8-bit unsigned integer (unsigned char)
            <DT>"INT16"<DD> 16-bit signed integer (short)
            <DT>"UINT16"<DD> 16-bit unsigned integer (unsigned short)
            <DT>"INT32"<DD> 32-bit signed integer (long)
            <DT>"UINT32"<DD> 32-bit unsigned integer (unsigned long)
            <DT>"INT64"<DD> 64-bit signed integer (long long)
            <DT>"UINT64"<DD> 64-bit unsigned integer (unsigned long long)
            <DT>"FLOAT"<DD> 32-bit floating point (float)
            <DT>"DOUBLE"<DD> 64-bit floating point (double)
            <DT>"UNKNOWN"<DD> any other type
            </DL>
         **/
    VIGRA_EXPORT const char * getPixelType() const;

        /** Query the pixel type of the volume data.

            Same as getPixelType(), but the result is returned as a
            ImageImportInfo::PixelType enum. This is useful to implement
            a switch() on the pixel type.

            Possible values are:
            <DL>
            <DT>UINT8<DD> 8-bit unsigned integer (unsigned char)
            <DT>INT16<DD> 16-bit signed integer (short)
            <DT>UINT16<DD> 16-bit unsigned integer (unsigned short)
            <DT>INT32<DD> 32-bit signed integer (long)
            <DT>UINT32<DD> 32-bit unsigned integer (unsigned long)
            <DT>FLOAT<DD> 32-bit floating point (float)
            <DT>DOUBLE<DD> 64-bit floating point (double)
            </DL>
         **/
    VIGRA_EXPORT PixelType pixelType() const;

    VIGRA_EXPORT MultiArrayIndex numBands() const;
    VIGRA_EXPORT bool isGrayscale() const;
    VIGRA_EXPORT bool isColor() const;

    // get base file name without path, image index, and extension
    VIGRA_EXPORT const std::string &name() const;

    VIGRA_EXPORT const std::string &description() const;

    template <class T, class Stride>
    void importImpl(MultiArrayView <3, T, Stride> &volume) const;

  protected:
    void getVolumeInfoFromFirstSlice(const std::string &filename);

    size_type shape_;
    Resolution resolution_;
    //PixelType pixelType_;
    int numBands_;

    std::string path_, name_, description_, fileType_, pixelType_;

    std::string rawFilename_;
    std::string baseName_, extension_;
    std::vector<std::string> numbers_;
};

/********************************************************/
/*                                                      */
/*                   VolumeExportInfo                    */
/*                                                      */
/********************************************************/

/** \brief Argument object for the function exportVolume().

    See \ref exportVolume() for usage example. This object must be used
    to define the properties of a volume to be written to disk.

    <b>\#include</b> <vigra/imageinfo.hxx> <br/>
    Namespace: vigra
**/
class VolumeExportInfo
{
  public:
        /** Construct VolumeExportInfo object to output volume data as a multi-page tiff.

            The filename must refer to a TIFF file (extension '.tif' or '.tiff'). This function
            is only available when libtiff is installed.
         **/
    VIGRA_EXPORT VolumeExportInfo( const char * filename );

        /** Construct VolumeExportInfo object to output volume data as an image stack.

            The volume will be stored in a by-slice manner, where the number of slices
            equals the depth of the volume. The file names will be enumerated like
            <tt>name_base+"000"+name_ext</tt>, <tt>name_base+"001"+name_ext</tt> etc.
            (the actual number of zeros depends on the depth). If the target image type
            does not support the source voxel type, all slices will be mapped
            simultaneously to the appropriate target range.
            The file type will be guessed from the extension unless overridden
            by \ref setFileType().

            Recognized extensions: '.bmp', '.gif',
            '.jpeg', '.jpg', '.p7', '.png', '.pbm', '.pgm', '.pnm', '.ppm', '.ras',
            '.tif', '.tiff', '.xv', '.hdr'.

            JPEG support requires libjpeg, PNG support requires libpng, and
            TIFF support requires libtiff.

            If \a name_ext is an empty string, the data is written as a multi-page tiff.
         **/
    VIGRA_EXPORT VolumeExportInfo( const char * name_base, const char * name_ext );
    VIGRA_EXPORT ~VolumeExportInfo();

        /** Set volume file name base.

        **/
    VIGRA_EXPORT VolumeExportInfo & setFileNameBase(const char * name_base);

        /** Set volume file name extension.

            The file type will be guessed from the extension unless overridden
            by \ref setFileType(). Recognized extensions: '.bmp', '.gif',
            '.jpeg', '.jpg', '.p7', '.png', '.pbm', '.pgm', '.pnm', '.ppm', '.ras',
            '.tif', '.tiff', '.xv', '.hdr'.

            JPEG support requires libjpeg, PNG support requires libpng, and
            TIFF support requires libtiff.
        **/
    VIGRA_EXPORT VolumeExportInfo & setFileNameExt(const char * name_ext);
    VIGRA_EXPORT const char * getFileNameBase() const;
    VIGRA_EXPORT const char * getFileNameExt() const;

        /** Store volume as given file type.

            This will override any type guessed
            from the file name's extension. Recognized file types:

            <DL>
            <DT>"BMP"<DD> Microsoft Windows bitmap image file.
            <DT>"GIF"<DD> CompuServe graphics interchange format; 8-bit color.
            <DT>"JPEG"<DD> Joint Photographic Experts Group JFIF format;
            compressed 24-bit color (only available if libjpeg is installed).
            <DT>"PNG"<DD> Portable Network Graphic
            (only available if libpng is installed).
            <DT>"PBM"<DD> Portable bitmap format (black and white).
            <DT>"PGM"<DD> Portable graymap format (gray scale).
            <DT>"PNM"<DD> Portable anymap.
            <DT>"PPM"<DD> Portable pixmap format (color).
            <DT>"SUN"<DD> SUN Rasterfile.
            <DT>"TIFF"<DD> Tagged Image File Format.
            (only available if libtiff is installed.)
            <DT>"MULTIPAGE"<DD> Multi-page TIFF.
               (only available if libtiff is installed.)
            <DT>"VIFF"<DD> Khoros Visualization image file.
            </DL>

            With the exception of TIFF, VIFF, PNG, and PNM all file types store
            only 1 byte (gray scale and mapped RGB) or 3 bytes (RGB) per
            pixel.

            PNG can store UInt8 and UInt16 values, and supports 1 and 3 channel
            images. One additional alpha channel is also supported.

            PNM can store 1 and 3 channel images with UInt8, UInt16 and UInt32
            values in each channel.

            TIFF and VIFF are additionally able to store short and long
            integers (2 or 4 bytes) and real values (32 bit float and
            64 bit double) without conversion. So you will need to use
            TIFF or VIFF if you need to store images with high
            accuracy (the appropriate type to write is automatically
            derived from the image type to be exported). However, many
            other programs using TIFF (e.g. ImageMagick) have not
            implemented support for those pixel types.  So don't be
            surprised if the generated TIFF is not readable in some
            cases.  If this happens, export the image as 'unsigned
            char' or 'RGBValue<unsigned char>' by calling
            \ref ImageExportInfo::setPixelType().

            Support to reading and writing ICC color profiles is
            provided for TIFF, JPEG, and PNG images.
         **/
    VIGRA_EXPORT VolumeExportInfo & setFileType( const char * );
    VIGRA_EXPORT const char * getFileType() const;

        /** Set compression type and quality.

            See \ref ImageExportInfo::setCompression() for details.
         **/
    VIGRA_EXPORT VolumeExportInfo & setCompression( const char * type);
    VIGRA_EXPORT const char * getCompression() const;

        /** Set the pixel type of the volume file(s). Possible values are:
            <DL>
            <DT>"UINT8"<DD> 8-bit unsigned integer (unsigned char)
            <DT>"INT16"<DD> 16-bit signed integer (short)
            <DT>"UINT16"<DD> 16-bit unsigned integer (unsigned short)
            <DT>"INT32"<DD> 32-bit signed integer (long)
            <DT>"UINT32"<DD> 32-bit unsigned integer (unsigned long)
            <DT>"FLOAT"<DD> 32-bit floating point (float)
            <DT>"DOUBLE"<DD> 64-bit floating point (double)
            </DL>
         **/
    VIGRA_EXPORT VolumeExportInfo & setPixelType( const char * );

        /** Get the pixel type of the images in the volume. Possible values are:
            <DL>
            <DT>"UINT8"<DD> 8-bit unsigned integer (unsigned char)
            <DT>"INT16"<DD> 16-bit signed integer (short)
            <DT>"INT32"<DD> 32-bit signed integer (long)
            <DT>"FLOAT"<DD> 32-bit floating point (float)
            <DT>"DOUBLE"<DD> 64-bit floating point (double)
            </DL>
         **/
    VIGRA_EXPORT const char * getPixelType() const;

    VIGRA_EXPORT VolumeExportInfo & setForcedRangeMapping(double fromMin, double fromMax,
                                                     double toMin, double toMax);
    VIGRA_EXPORT bool hasForcedRangeMapping() const;
    VIGRA_EXPORT double getFromMin() const;
    VIGRA_EXPORT double getFromMax() const;
    VIGRA_EXPORT double getToMin() const;
    VIGRA_EXPORT double getToMax() const;

        /** Set the volume resolution in horizontal direction
         **/
    VIGRA_EXPORT VolumeExportInfo & setXResolution( float );
    VIGRA_EXPORT float getXResolution() const;

        /** Set the image resolution in vertical direction
         **/
    VIGRA_EXPORT VolumeExportInfo & setYResolution( float );
    VIGRA_EXPORT float getYResolution() const;

        /** Set the image resolution in depth direction
         **/
    VIGRA_EXPORT VolumeExportInfo & setZResolution( float );
    VIGRA_EXPORT float getZResolution() const;

        /** Set the position of the upper Left corner on a global
            canvas.

            Currently only supported by TIFF and PNG files.

            The offset is encoded in the XPosition and YPosition TIFF tags.

            @param pos     position of the upper left corner in pixels
                           (must be >= 0)
         **/
    // FIXME: mhanselm: we might want to support 3D positions
    VIGRA_EXPORT VolumeExportInfo & setPosition(const Diff2D & pos);

        /** Get the position of the upper left corner on
            a global canvas.
         **/
    // FIXME: mhanselm: we might want to support 3D positions
    VIGRA_EXPORT Diff2D getPosition() const;

        /**
          ICC profiles (handled as raw data so far).
          see getICCProfile()/setICCProfile()
         **/
    typedef ArrayVector<unsigned char> ICCProfile;

        /** Returns a reference to the ICC profile.
         */
    VIGRA_EXPORT const ICCProfile & getICCProfile() const;

        /** Sets the ICC profile.
            ICC profiles are currently supported by TIFF, PNG and JPEG images.
            (Otherwise, the profile data is silently ignored.)
         **/
    VIGRA_EXPORT VolumeExportInfo & setICCProfile(const ICCProfile & profile);

  private:
    float m_x_res, m_y_res, m_z_res;

    std::string m_filetype, m_filename_base, m_filename_ext, m_pixeltype, m_comp;
    Diff2D m_pos;
    ICCProfile m_icc_profile;
    double fromMin_, fromMax_, toMin_, toMax_;
};

namespace detail {

template <class DestIterator, class Shape, class T>
inline void
readVolumeImpl(DestIterator d, Shape const & shape, std::ifstream & s, ArrayVector<T> & buffer, MetaInt<0>)
{
    s.read(reinterpret_cast<char*>(buffer.begin()), shape[0]*sizeof(T));

    DestIterator dend = d + shape[0];
    int k = 0;
    for(; d < dend; ++d, k++)
    {
        *d = buffer[k];
    }
}

template <class DestIterator, class Shape, class T, int N>
void
readVolumeImpl(DestIterator d, Shape const & shape, std::ifstream & s, ArrayVector<T> & buffer, MetaInt<N>)
{
    DestIterator dend = d + shape[N];
    for(; d < dend; ++d)
    {
        readVolumeImpl(d.begin(), shape, s, buffer, MetaInt<N-1>());
    }
}

} // namespace detail

template <class T, class Stride>
void VolumeImportInfo::importImpl(MultiArrayView <3, T, Stride> &volume) const
{
    vigra_precondition(this->shape() == volume.shape(), "importVolume(): Output array must be shaped according to VolumeImportInfo.");

    if(fileType_ == "RAW")
    {
        std::string dirName, baseName;
        char oldCWD[2048];

#ifdef _MSC_VER
        if(_getcwd(oldCWD, 2048) == 0)
        {
            perror("getcwd");
            vigra_fail("VolumeImportInfo: Unable to query current directory (getcwd).");
        }
        if(_chdir(path_.c_str()))
        {
            perror("chdir");
            vigra_fail("VolumeImportInfo: Unable to change to new directory (chdir).");
        }
#else
        if(getcwd(oldCWD, 2048) == 0)
        {
            perror("getcwd");
            vigra_fail("VolumeImportInfo: Unable to query current directory (getcwd).");
        }
        if(chdir(path_.c_str()))
        {
            perror("chdir");
            vigra_fail("VolumeImportInfo: Unable to change to new directory (chdir).");
        }
#endif

        std::ifstream s(rawFilename_.c_str(), std::ios::binary);
        vigra_precondition(s.good(), "RAW file could not be opened");

        ArrayVector<T> buffer(shape_[0]);
        detail::readVolumeImpl(volume.traverser_begin(), shape_, s, buffer, vigra::MetaInt<2>());

        //vigra_precondition(s.good(), "RAW file could not be opened");
        //s.read((char*)volume.data(), shape_[0]*shape_[1]*shape_[2]*sizeof(T));

#ifdef _MSC_VER
        if(_chdir(oldCWD))
            perror("chdir");
#else
        if(chdir(oldCWD))
            perror("chdir");
#endif

        vigra_postcondition(
            volume.shape() == shape(), "imported volume has wrong size");
    }
    else if(fileType_ == "STACK")
    {
        for (unsigned int i = 0; i < numbers_.size(); ++i)
        {
            // build the filename
            std::string filename = baseName_ + numbers_[i] + extension_;

            // import the image
            ImageImportInfo info (filename.c_str ());

            // generate a basic image view to the current layer
            MultiArrayView <2, T, Stride> view (volume.bindOuter (i));
            vigra_precondition(view.shape() == info.shape(),
                "importVolume(): the images have inconsistent sizes.");

            importImage (info, destImage(view));
        }
    }
    else if(fileType_ == "MULTIPAGE")
    {
        ImageImportInfo info(baseName_.c_str());

        for(int k=0; k<info.numImages(); ++k)
        {
            info.setImageIndex(k);
            importImage(info, volume.bindOuter(k));
        }
    }
    // else if(fileType_ == "HDF5")
    // {
        // HDF5File file(baseName_, HDF5File::OpenReadOnly);
        // file.read(extension_, volume);
    // }
    else if(fileType_ == "SIF")
    {
        SIFImportInfo infoSIF(baseName_.c_str());
        readSIF(infoSIF, volume);
    }
}


VIGRA_EXPORT void findImageSequence(const std::string &name_base,
                       const std::string &name_ext,
                       std::vector<std::string> & numbers);

/********************************************************/
/*                                                      */
/*                    importVolume                      */
/*                                                      */
/********************************************************/

/** \brief Function for importing a 3D volume.

    <b>Declarations: </b>

    \code
    namespace vigra {
        // variant 1: read data specified by the given VolumeImportInfo object
        template <class T, class Stride>
        void
        importVolume(VolumeImportInfo const & info,
                     MultiArrayView <3, T, Stride> &volume);

        // variant 2: read data using a single filename, resize volume automatically
        template <class T, class Allocator>
        void
        importVolume(MultiArray <3, T, Allocator> & volume,
                     const std::string &filename);

        // variant 3: read data from an image stack, resize volume automatically
        template <class T, class Allocator>
        void
        importVolume(MultiArray <3, T, Allocator> & volume,
                     const std::string &name_base,
                     const std::string &name_ext);
    }
    \endcode

    Data can be read either from a single file containing 3D data (supported formats:
    Andor .SIF or multi-page TIFF), a ".info" text file which describes the contents of
    an accompanying raw data file, or a stack of 2D images (numbered according to the
    scheme <tt>name_base+"[0-9]+"+name_extension</tt>) each representing a slice of
    the volume. The decision which of these possibilities applies is taken in the
    \ref vigra::VolumeImportInfo::VolumeImportInfo(const std::string &) "VolumeImportInfo constructor",
    see there for full details.

    Variant 1 is the basic version of this function. Here, the info object and a destination
    array of approriate size must already be constructed. The other variants are just abbreviations
    provided for your convenience:
    \code
    // variant 2 is equivalent to
    VolumeImportInfo info(filename);
    volume.reshape(info.shape());
    importVolume(info, volume);    // call variant 1

    // variant 3 is equivalent to
    VolumeImportInfo info(name_base, name_ext);
    volume.reshape(info.shape());
    importVolume(info, volume);    // call variant 1
    \endcode

    <b> Usage:</b>

    <b>\#include</b> <vigra/multi_impex.hxx> <br/>
    Namespace: vigra

    \code
    // read data from a multi-page TIFF file, using variant 1
    VolumeImportInfo info("multipage.tif");
    MultiArray<3, float> volume(info.shape());
    importVolume(info, volume);

    // read data from a stack of 2D png-images, using variant 1
    VolumeImportInfo info("my_data", ".png");  // looks for files 'my_data0.png', 'my_data1.png' etc.
    MultiArray<3, float> volume(info.shape());
    importVolume(info, volume);
    \endcode
    Notice that slice numbers in a stack need not be consecutive (i.e. gaps are allowed) and
    will be interpreted according to their numerical order (i.e. "009", "010", "011"
    are read in the same order as "9", "10", "11"). The number of images
    found determines the depth of the volume.
*/
doxygen_overloaded_function(template <...> void importVolume)

template <class T, class Stride>
void
importVolume(VolumeImportInfo const & info,
             MultiArrayView <3, T, Stride> &volume)
{
    info.importImpl(volume);
}

template <class T, class Allocator>
void
importVolume(MultiArray <3, T, Allocator> &volume,
             const std::string &filename)
{
    VolumeImportInfo info(filename);
    volume.reshape(info.shape());

    info.importImpl(volume);
}

template <class T, class Allocator>
void importVolume (MultiArray <3, T, Allocator> & volume,
                   const std::string &name_base,
                   const std::string &name_ext)
{
    VolumeImportInfo info(name_base, name_ext);
    volume.reshape(info.shape());

    info.importImpl(volume);
}

namespace detail {

template <class T>
void setRangeMapping(std::string const & pixeltype,
                     FindMinMax<T> const & minmax, ImageExportInfo & info)
{
    if(pixeltype == "UINT8")
        info.setForcedRangeMapping((double)minmax.min, (double)minmax.max,
                                   (double)NumericTraits<UInt8>::min(),
                                   (double)NumericTraits<UInt8>::max());
    else if(pixeltype == "INT16")
        info.setForcedRangeMapping((double)minmax.min, (double)minmax.max,
                                   (double)NumericTraits<Int16>::min(),
                                   (double)NumericTraits<Int16>::max());
    else if(pixeltype == "UINT16")
        info.setForcedRangeMapping((double)minmax.min, (double)minmax.max,
                                   (double)NumericTraits<UInt16>::min(),
                                   (double)NumericTraits<UInt16>::max());
    else if(pixeltype == "INT32")
        info.setForcedRangeMapping((double)minmax.min, (double)minmax.max,
                                   (double)NumericTraits<Int32>::min(),
                                   (double)NumericTraits<Int32>::max());
    else if(pixeltype == "UINT32")
        info.setForcedRangeMapping((double)minmax.min, (double)minmax.max,
                                   (double)NumericTraits<UInt32>::min(),
                                   (double)NumericTraits<UInt32>::max());
    else if(pixeltype == "FLOAT")
        info.setForcedRangeMapping((double)minmax.min, (double)minmax.max, 0.0, 1.0);
    else if(pixeltype == "DOUBLE")
        info.setForcedRangeMapping((double)minmax.min, (double)minmax.max, 0.0, 1.0);
}

template <class T, class Tag>
void setRangeMapping(MultiArrayView <3, T, Tag> const & volume,
                     ImageExportInfo & info, VigraTrueType /* isScalar */)
{
    std::string pixeltype = info.getPixelType();
    bool downcast = negotiatePixelType(getEncoderType(info.getFileName(), info.getFileType()),
                                       TypeAsString<T>::result(), pixeltype);

    if(downcast)
    {
        FindMinMax<T> minmax;
        inspectMultiArray(srcMultiArrayRange(volume), minmax);
        setRangeMapping(pixeltype, minmax, info);
    }
}

template <class T, class Tag>
void setRangeMapping(MultiArrayView <3, T, Tag> const & volume,
                     ImageExportInfo & info, VigraFalseType /* isScalar */)
{
    typedef typename T::value_type SrcComponent;
    std::string pixeltype = info.getPixelType();
    bool downcast = negotiatePixelType(getEncoderType(info.getFileName(), info.getFileType()),
                                       TypeAsString<SrcComponent>::result(), pixeltype);

    if(downcast)
    {
        unsigned int bands = volume(0,0,0).size();
        FindMinMax<SrcComponent> minmax;
        for(unsigned int i=0; i<bands; ++i)
        {
            VectorComponentValueAccessor<T> band(i);
            inspectMultiArray(srcMultiArrayRange(volume, band), minmax );
        }
        setRangeMapping(pixeltype, minmax, info);
    }
}

} // namespace detail

/********************************************************/
/*                                                      */
/*                    exportVolume                      */
/*                                                      */
/********************************************************/

/** \brief Function for exporting a 3D volume.

    <b> Declarations:</b>

    \code
    namespace vigra {
        // variant 1: writa data as specified in the given VolumeExportInfo object
        template <class T, class Tag>
        void
        exportVolume (MultiArrayView <3, T, Tag> const & volume,
                      const VolumeExportInfo & info);

        // variant 2: write data to a multi-page TIFF file
        template <class T, class Tag>
        void
        exportVolume (MultiArrayView <3, T, Tag> const & volume,
                      const std::string &filename);

        // variant 3: write data to an image stack
        template <class T, class Tag>
        void
        exportVolume (MultiArrayView <3, T, Tag> const & volume,
                      const std::string &name_base,
                      const std::string &name_ext);
    }
    \endcode

    The volume can either be exported as a multi-page TIFF file (variant 2, only available if
    libtiff is installed), or as a stack of 2D images, one image per slice (variant 3, files are named
    according to the scheme <tt>name_base+"000"+name_ext</tt>, <tt>name_base+"001"+name_ext</tt> etc.).
    If the target image format does not support the source <tt>value_type</tt>, all slices will
    be mapped to the appropriate target range in the same way.

    Variant 1 is the basic version of the function. It allows full control over the export via
    an already constructed \ref vigra::VolumeExportInfo object. The other two are just abbreviations
    that construct the VolumeExportInfo object internally.

    <b> Usage:</b>

    <b>\#include</b> <vigra/multi_impex.hxx> <br/>
    Namespace: vigra

    \code
    MultiArray<3, RGBValue<UInt8> > volume(shape);
    ... // fill in data

    // export a stack named "my_data01.jpg", "my_data02.jpg" etc.
    VolumeExportInfo info("my_data", ".jpg");
    info.setCompression("JPEG QUALITY=95");
    exportVolume(volume, info);
    \endcode
*/
doxygen_overloaded_function(template <...> void exportVolume)

template <class T, class Tag>
void
exportVolume (MultiArrayView <3, T, Tag> const & volume,
              const VolumeExportInfo & volinfo)
{
    if(volinfo.getFileType() == std::string("MULTIPAGE"))
    {
        char const * mode = "w";
        std::string compression = "LZW";
        if(volinfo.getCompression() != std::string())
            compression = volinfo.getCompression();

        for(MultiArrayIndex k=0; k<volume.shape(2); ++k)
        {
            ImageExportInfo info(volinfo.getFileNameBase(), mode);
            info.setFileType("TIFF");
            info.setCompression(compression.c_str());
            info.setPixelType(volinfo.getPixelType());
            detail::setRangeMapping(volume, info, typename NumericTraits<T>::isScalar());
            exportImage(volume.bindOuter(k), info);
            mode = "a";
        }
    }
    else
    {
        std::string name = std::string(volinfo.getFileNameBase()) + std::string(volinfo.getFileNameExt());
        ImageExportInfo info(name.c_str());
        info.setCompression(volinfo.getCompression());
        info.setPixelType(volinfo.getPixelType());
        detail::setRangeMapping(volume, info, typename NumericTraits<T>::isScalar());

        const unsigned int depth = volume.shape (2);
        int numlen = static_cast <int> (std::ceil (std::log10 ((double)depth)));
        for (unsigned int i = 0; i < depth; ++i)
        {
            // build the filename
            std::stringstream stream;
            stream << std::setfill ('0') << std::setw (numlen) << i;
            std::string name_num;
            stream >> name_num;
            std::string sliceFilename =
                std::string(volinfo.getFileNameBase()) +
                name_num +
                std::string(volinfo.getFileNameExt());

            MultiArrayView <2, T, Tag> view (volume.bindOuter (i));

            // export the image
            info.setFileName(sliceFilename.c_str ());
            exportImage(srcImageRange(view), info);
        }
    }
}

template <class T, class Tag>
inline void
exportVolume (MultiArrayView <3, T, Tag> const & volume,
              const std::string &filename)
{
    VolumeExportInfo volinfo(filename.c_str());
    exportVolume(volume, volinfo);
}

template <class T, class Tag>
inline void
exportVolume (MultiArrayView <3, T, Tag> const & volume,
              const std::string &name_base,
              const std::string &name_ext)
{
    VolumeExportInfo volinfo(name_base.c_str(), name_ext.c_str());
    exportVolume(volume, volinfo);
}

//@}

} // namespace vigra

#endif // VIGRA_MULTI_IMPEX_HXX