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Дата изменения: Fri Sep 11 17:33:25 1998 Дата индексирования: Tue Oct 2 12:45:42 2012 Кодировка: Поисковые слова: total solar eclipse |
#include "ImageIO.h" // types of image data (these mostly correspond to the FITS BITPIX values) enum ImageDataType { UNKNOWN_IMAGE = -1, // unknown type BYTE_IMAGE = 8, // 8 bit images X_IMAGE = -8, // special, color scaled, X image data SHORT_IMAGE = 16, // 16 bit signed USHORT_IMAGE = -16, // 16 bit unsigned LONG_IMAGE = 32, // 32 bit integer FLOAT_IMAGE = -32 // 32 bit floating point }; class ImageIORep { ... }; class FitsIO : public ImageIORep { ... }; class ImageIO; ... public: ImageIO(); ImageIO(ImageIORep* rep); ImageIO(const ImageIO&); ~ImageIO(); ImageIO& operator=(const ImageIO&); int nativeByteOrder() const; int write(const char *filename) const; int wcsinit(); int get(const char* keyword, double& val) const; int get(const char* keyword, float& val) const; int get(const char* keyword, int& val) const; int get(const char* keyword, long& val) const; int get(const char* keyword, unsigned char& val) const; int get(const char* keyword, unsigned short& val) const; int get(const char* keyword, short& val) const; char* get(const char* keyword) const; int getFitsHeader(ostream& os) const; double scaleValue(double d) const; double unScaleValue(double d) const; int pixelSize() const; int width() const; int height() const; int bitpix() const; double bscale() const; double bzero() const; const Mem& header() const; const Mem& data() const; WCS& wcs(); void wcs(const WCS& newwcs); int header(const Mem& m); int data(const Mem& m); const char* headerPtr() const; const void* dataPtr() const; int status() const; ImageIORep* rep() const; };
Class ImageIO is used to read, write and manage the memory for astronomical images of various formats. The image header and data may be optionally kept in shared memory (mmap or shm), so they can be accessed by external processes that may want to do image processing or other operations. Regardless of the original image format and derived class, the header and data are always kept in FITS format. Other image types are converted to FITS format by the derived classes (see below). Subclasses of ImageIORep can, however, specify via a virtual method whether the image data is in network or in native byte order (see below).
Class ImageIO uses reference counting to make it easier to share objects of this type for displaying in multiple windows. The actual (abstract) base class is ImageIORep. An ImageIO object contains a pointer to an ImageIORep object, which may be shared by multiple ImageIO objects. To add new image types, to the ImageIO class, classes are derived from ImageIORep.
This class offers optional support of world coordinates for the image, which can be initialized by calling the wcsinit() method, which must be defined in a derived class, such as FitsIO. Normally wcsinit() will get the necessary information from the image header, which is normally assumed to be in FITS format.
ImageIO() Default constructor, creates a null object (use assignment operator to set later); ImageIO(ImageIORep* rep) Constructor, from a pointer to a subclass of ImageIORep (FitsIO, for example). "rep" should be allocated with the "new" operator and will be deleted by this class when there are no more references to it. Note that this constructors enables automatic conversion from a pointer to a subclass of ImageIORep to class ImageIO. Examples: // create an ImageIO object from a FITS file ImageIO imio1 = FitsIO::read(filename); // create an ImageIO object from FITS data and header in memory Mem header(...), data(...); ImageIO imio2 = new FitsIO(w, h, type, bzero, bscale, header, data); ImageIO(const ImageIO&) Copy constructor: only copies the internal pointer and raises the reference count. ~ImageIO() Destructor, lowers the reference count and frees the memory, if there are no more references. ImageIO& operator=(const ImageIO&) Assignment operator: reference counted. nativeByteOrder() Return true if the ImageIORep subclass uses native byte ordering. FITS files and most other image formats are in network byte order, however, the derived class may want to byte swap the data first, if needed, so that it is easier to work with. This virtual method is checked by classes that use this object to determine if byte-swapping may need to be done. write(filename) Write the image header and data to a file in a format defined in the derived class. get(keyword, val) Find and set the value for the given FITS keyword and return 0 if OK (found). This method is overloaded for various data types. get(keyword) Find and return the string value for the given FITS keyword, or NULL if not found. scaleValue(d) Apply the FITS keyword values for BZERO and BSCALE to the given value (d = BZERO+d*BSCALE) unScaleValue(d) Reverse the effect of BZERO and BSCALE (d = (d-BZERO)/BSCALE) width() Return the width of the image in pixels. height() Return the height of the image in pixels. bitpix() Return the value of the BITPIX keyword (data type of image). bscale() Return value for the BSCALE keyword. bzero() Return the value for the BZERO keyword. header() Return a reference to the FITS header (class Mem). data() Return a reference to the FITS image data (class Mem). header(const Mem& newheader) Replace teh image header. data(const Mem& newdata) Replace the image data with new data of same size. WCS& wcs() Return a reference to the object used to manage world coordinates. Note that this object is reference counted in the same way as the ImageIO class. void wcs(const WCS& newwcs) Set the WCS object used to manage world coordinates. Since the WCS class is also a reference counted wrapper around an abstract base class (WCSRep), you can define subclasses of class WCSRep that redefines the behavior and implementation of the WCS object.
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