CCfits  2.4
Public Member Functions | Protected Member Functions
CCfits::PHDU Class Reference

class representing the primary HDU for a FITS file. More...

#include <PHDU.h>

Inheritance diagram for CCfits::PHDU:
Inheritance diagram CCfits::HDU

List of all members.

Public Member Functions

virtual ~PHDU ()
 destructor
virtual PHDUclone (FITSBase *p) const =0
 virtual copy constructor, to be implemented in subclasses.
bool extend () const
 Returns the value of the Primary's EXTEND keyword.
template<typename S >
void read (std::valarray< S > &image, long first, long nElements)
 read an image section starting at a specified pixel
template<typename S >
void read (std::valarray< S > &image, long first, long nElements, S *nullValue)
 read part of an image array, processing null values.
template<typename S >
void read (std::valarray< S > &image, const std::vector< long > &first, long nElements)
 read an image section starting at a location specified by an n-tuple
template<typename S >
void read (std::valarray< S > &image, const std::vector< long > &first, long nElements, S *nullValue)
 read part of an image array, processing null values.
template<typename S >
void read (std::valarray< S > &image, const std::vector< long > &firstVertex, const std::vector< long > &lastVertex, const std::vector< long > &stride)
 read an image subset
template<typename S >
void read (std::valarray< S > &image, const std::vector< long > &firstVertex, const std::vector< long > &lastVertex, const std::vector< long > &stride, S *nullValue)
 read an image subset into valarray image, processing null values
virtual void readData (bool readFlag=false, const std::vector< String > &keys=std::vector< String >())=0
 read primary HDU data
virtual void scale (double value)
 set the BSCALE keyword value for images (see warning for images of int type)
virtual double scale () const
 return the BSCALE keyword value
bool simple () const
 Returns the value of the Primary's SIMPLE keyword.
template<typename S >
void write (const std::vector< long > &first, long nElements, const std::valarray< S > &data, S *nullValue)
 Write a set of pixels to an image extension with the first pixel specified by an n-tuple, processing undefined data.
template<typename S >
void write (long first, long nElements, const std::valarray< S > &data, S *nullValue)
 write array to image starting with a specified pixel and allowing undefined data to be processed
template<typename S >
void write (const std::vector< long > &first, long nElements, const std::valarray< S > &data)
 write array starting from specified n-tuple, without undefined data processing
template<typename S >
void write (long first, long nElements, const std::valarray< S > &data)
 write array starting from specified pixel number, without undefined data processing
template<typename S >
void write (const std::vector< long > &firstVertex, const std::vector< long > &lastVertex, const std::vector< long > &stride, const std::valarray< S > &data)
 write a subset (generalize slice) of data to the image
virtual void zero (double value)
 set the BZERO keyword value for images (see warning for images of int type)
virtual double zero () const
 return the BZERO keyword value

Protected Member Functions

 PHDU (const PHDU &right)
 copy constructor
 PHDU (FITSBase *p, int bpix, int naxis, const std::vector< long > &axes)
 Writing Primary HDU constructor, called by PrimaryHDU<T> class.
 PHDU (FITSBase *p=0)
 Reading Primary HDU constructor.
virtual void initRead ()

Detailed Description

class representing the primary HDU for a FITS file.

A PHDU object is automatically instantiated and added to a FITS object when a FITS file is accessed in any way. If a new file is created without specifying the data type for the header, CCfits assumes that the file is to be used for table extensions and creates a dummy header. PHDU instances are only created by FITS ctors. In the first release of CCfits, the Primary cannot be changed once declared.

PHDU and ExtHDU provide the same interface to writing images: multiple overloads of the templated PHDU::read and PHDU::write operations provide for (a) writing image data specified in a number of ways [C-array, std::vector, std::valarray] and with input location specified by initial pixel, by n-tuple, and by rectangular subset [generalized slice]; (b) reading image data specified similarly to the write options into a std::valarray.

Todo:
Implement functions that allow replacement of the primary image

Constructor & Destructor Documentation

CCfits::PHDU::~PHDU ( ) [virtual]

destructor

Destructor

CCfits::PHDU::PHDU ( const PHDU right) [protected]

copy constructor

required for cloning primary HDUs when copying FITS files.

CCfits::PHDU::PHDU ( FITSBase *  p,
int  bpix,
int  naxis,
const std::vector< long > &  axes 
) [protected]

Writing Primary HDU constructor, called by PrimaryHDU<T> class.

Constructor used for creating new PHDU (i.e. for writing data to FITS). also doubles as default constructor since all arguments have default values, which are passed to the HDU constructor

CCfits::PHDU::PHDU ( FITSBase *  p = 0) [protected]

Reading Primary HDU constructor.

Constructor used when reading the primary HDU from an existing file. Does nothing except initialize, with the real work done by the subclass PrimaryHDU<T>.


Member Function Documentation

void CCfits::PHDU::initRead ( ) [protected, virtual]

Read image header and update fits pointer accordingly.

Private: called by ctor.

Implements CCfits::HDU.

template<typename S >
void CCfits::PHDU::read ( std::valarray< S > &  image,
long  first,
long  nElements,
S *  nullValue 
)

read part of an image array, processing null values.

Implicit data conversion is supported (i.e. user does not need to know the type of the data stored. A WrongExtensionType extension is thrown if *this is not an image.

Parameters:
imageThe receiving container, a std::valarray reference
firstThe first pixel from the array to read [a long value]
nElementsThe number of values to read
nullValueA pointer containing the value in the table to be considered as undefined. See cfitsio for details
template<typename S >
void CCfits::PHDU::read ( std::valarray< S > &  image,
const std::vector< long > &  first,
long  nElements,
S *  nullValue 
)

read part of an image array, processing null values.

As above except for

Parameters:
firsta vector<long> representing an n-tuple giving the coordinates in the image of the first pixel.
template<typename S >
void CCfits::PHDU::read ( std::valarray< S > &  image,
const std::vector< long > &  firstVertex,
const std::vector< long > &  lastVertex,
const std::vector< long > &  stride,
S *  nullValue 
)

read an image subset into valarray image, processing null values

The image subset is defined by two vertices and a stride indicating the 'denseness' of the values to be picked in each dimension (a stride = (1,1,1,...) means picking every pixel in every dimension, whereas stride = (2,2,2,...) means picking every other value in each dimension.

void CCfits::PHDU::readData ( bool  readFlag = false,
const std::vector< String > &  keys = std::vector<String>() 
) [pure virtual]

read primary HDU data

Called by FITS ctor, not intended for general use. parameters control how much gets read on initialization. An abstract function, implemented in the subclasses.

Parameters:
readFlagread the image data if true
keya vector of strings of keyword names to be read from the primary HDU
void CCfits::PHDU::scale ( double  value) [virtual]

set the BSCALE keyword value for images (see warning for images of int type)

For primary HDUs and image extensions, this will add (or update) the BSCALE keyword in the header. The new setting will affect future image array read/writes as described in section 4.7 Data Scaling of the CFITSIO manual. For table extensions this function does nothing.

WARNING: If the image contains integer-type data (as indicated by the bitpix() return value), the new scale and zero value combination must not be such that the scaled data would require a floating-point type (this uses the CFITSIO function fits_get_img_equivtype to make the determination). If this situation occurs, the function will throw a FitsException.

Reimplemented from CCfits::HDU.

template<typename S >
void CCfits::PHDU::write ( const std::vector< long > &  first,
long  nElements,
const std::valarray< S > &  data,
S *  nullValue 
)

Write a set of pixels to an image extension with the first pixel specified by an n-tuple, processing undefined data.

All the overloaded versions of PHDU::write perform operations on *this if it is an image and throw a WrongExtensionType exception if not. Where appropriate, alternate versions allow undefined data to be processed

Parameters:
firstan n-tuple of dimension equal to the image dimension specifying the first pixel in the range to be written
nElementsnumber of pixels to be written
dataarray of data to be written
nullValuepointer to null value (data with this value written as undefined; needs the BLANK keyword to have been specified).
template<typename S >
void CCfits::PHDU::write ( long  first,
long  nElements,
const std::valarray< S > &  data,
S *  nullValue 
)

write array to image starting with a specified pixel and allowing undefined data to be processed

parameters after the first are as for version with n-tuple specifying first element. these two version are equivalent, except that it is possible for the first pixel number to exceed the range of 32-bit integers, which is how long datatype is commonly implemented.

template<typename S >
void CCfits::PHDU::write ( const std::vector< long > &  firstVertex,
const std::vector< long > &  lastVertex,
const std::vector< long > &  stride,
const std::valarray< S > &  data 
)

write a subset (generalize slice) of data to the image

A generalized slice/subset is a subset of the image (e.g. one plane of a data cube of size <= the dimension of the cube). It is specified by two opposite vertices. The equivalent cfitsio call does not support undefined data processing so there is no version that allows a null value to be specified.

Parameters:
firstVertexThe coordinates specifying lower and upper vertices of the n-dimensional slice
lastVertex
stridePixels to skip in each to dimension, e.g. stride = (1,1,1,...) means picking every pixel in every dimension, whearas stride = (2,2,2,...) means picking every other value in each dimension.
dataThe data to be written
void CCfits::PHDU::zero ( double  value) [virtual]

set the BZERO keyword value for images (see warning for images of int type)

For primary HDUs and image extensions, this will add (or update) the BZERO keyword in the header. The new setting will affect future image array read/writes as described in section 4.7 Data Scaling of the CFITSIO manual. For table extensions this function does nothing.

WARNING: If the image contains integer-type data (as indicated by the bitpix() return value), the new scale and zero value combination must not be such that the scaled data would require a floating-point type (this uses the CFITSIO function fits_get_img_equivtype to make the determination). If this situation occurs, the function will throw a FitsException.

Reimplemented from CCfits::HDU.


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