TempImage.h

virtual void setCacheSizeFromPath (const IPosition& sliceShape, const IPosition& windowStart, const IPosition& windowLength, const IPosition& axisPath)

virtual void setCacheSizeInTiles (uInt howManyTiles)

virtual void clearCache()

virtual void showCacheStatistics (ostream& os) const

virtual Bool ok() const

Protected Members

virtual const LatticeRegion* getRegionPtr() const

virtual Bool doGetSlice (Array<T>& buffer, const Slicer& theSlice)

virtual void doPutSlice (const Array<T>& sourceBuffer, const IPosition& where, const IPosition& stride)

Private Members

void applyMaskSpecifier (const MaskSpecifier&)

void applyMask (const String& maskName)

Description

Review Status

Programs:

Tests:

tTempImage.cc

Prerequisite

CoordinateSystem ImageInterface TempLattice

Etymology

The TempImage name comes from its role as the Image class for temporary storage.

Synopsis

The class TempImage is useful for storing temporary images for which it is not known whether they can be held in memory. It uses class TempLattice to hold the image in memory when it is small enough. Otherwise it is held in a temporary file. Similarly to TempLattice one can give the maximum memory to use to control when the image can be held in memory.
The other Image information like coordinates, units, and miscinfo is held in member variables and disappears when the TempImage object is destructed.

It is possibly to temporarily close a TempImage, which only takes effect when it is created as a PagedArray. In this way it is possible to reduce the number of open files in case a lot of TempImage objects are used. A temporarily closed TempImage will be reopened automatically when needed. It can also be reopened explicitly.

Example

Motivation

The size of astronomical data can be very large. The ability to fit an entire image into random access memory cannot be guaranteed. Paging from disk pieces of the image appeared to be the way to deal with this problem.

Member Description

TempImage()

The default constructor creates an empty image.

TempImage (const TiledShape& mapShape, const CoordinateSystem& coordinateInfo, Int maxMemoryInMB=-1)

Construct a temporary Image from shape and coordinate information. If the image is sufficiently small, it is kept in memory. Otherwise it is kept in a temporary disk table. It can be forced to disk by setting maxMemoryinMB=0. The algorithm is the same as in class TempLattice.

TempImage (const TiledShape& mapShape, const CoordinateSystem& coordinateInfo, Double maxMemoryInMB)

TempImage (const TempImage<T>& other)

Copy constructor (reference semantics).

~TempImage()

Destructor

TempImage<T>& operator= (const TempImage<T>& other)

Assignment operator (reference semantics).

virtual ImageInterface<T>* cloneII() const

Make a copy of the object (reference semantics).

virtual String imageType() const

Get the image type (returns name of derived class).

virtual Bool isPaged() const

Is the TempImage paged to disk?

virtual Bool canReferenceArray() const

Can the lattice data be referenced as an array section?

virtual Bool isWritable() const

Is the TempImage writable?

virtual void setDefaultMask (const String& maskName)

Set the default pixelmask to the mask with the given name (which has to exist in the "masks" group). If the image table is writable, the setting is persistent by writing the name as a keyword. If the given regionName is the empty string, the default pixelmask is unset.

void removeMask()

Delete the pixel mask attached to the TempImage. Does nothing if there isn't one

virtual void useMask (MaskSpecifier = MaskSpecifier())

Use the mask as specified. If a mask was already in use, it is replaced by the new one.

virtual void removeRegion (const String& name, RegionHandler::GroupType = RegionHandler::Any, Bool throwIfUnknown = True)

Remove a region/mask belonging to the image from the given group (which can be Any). If a mask removed is the default mask, the image gets unmasked.
Optionally an exception is thrown if the region does not exist.

virtual void attachMask (const Lattice<Bool>& mask)

Attach a mask to the TempImage. It replaces a probably already attached mask. It has to have the same shape as the image.

virtual Bool isMasked() const

It a mask attached to the image?

virtual Bool hasPixelMask() const

Does the image object use a pixelmask? This is similar to isMasked().

virtual const Lattice<Bool>& pixelMask() const
virtual Lattice<Bool>& pixelMask()

Get access to the pixelmask used. An exception is thrown if the image does not use a pixelmask.

virtual Bool doGetMaskSlice (Array<Bool>& buffer, const Slicer& section)

Get a section of the mask. It throws an exception if there is no mask.

virtual void flush()

Flush the data.

virtual void tempClose()

Close the TempImage temporarily (if it is paged to disk). Note that a possible mask is not closed. It'll be reopened automatically when needed or when reopen is called explicitly.

virtual void reopen()

If needed, reopen a temporarily closed TempLattice.

virtual void resize (const TiledShape& newShape)

Function which changes the shape of the image (N.B. the data is thrown away - the Image will be filled with nonsense afterwards)

virtual String name (Bool stripPath=False) const

Return the name of the current TempImage object. It is always "Temporary_Image"

virtual IPosition shape() const

Return the shape of the image

virtual void set (const T& value)

Function which sets all of the elements in the Lattice to a value.

virtual void apply (T (function)(T))
virtual void apply (T (function)(const T&))
virtual void apply (const Functional<T,T>& function)

Replace every element, x, of the lattice with the result of f(x). You must pass in the address of the function -- so the function must be declared and defined in the scope of your program. Both versions of apply require a function that accepts a single argument of type T (the Lattice template actual type) and returns a result of the same type. The first apply expects a function with an argument passed by value; the second expects the argument to be passed by const reference. The first form ought to run faster for the built-in types, which may be an issue for large images stored in memory, where disk access is not an issue.

virtual T getAt (const IPosition& where) const
virtual void putAt (const T& value, const IPosition& where)

Get or put a single pixel. Note that the function operator () can also be used to get a pixel.

virtual LatticeIterInterface<T>* makeIter (const T& navigator, Bool useRef) const

This is the implementations of the letters for the envelope Iterator class Not for public use

virtual uInt advisedMaxPixels() const

Returns the maximum recommended number of pixels for a cursor. This is the number of pixels in a tile.

virtual IPosition doNiceCursorShape (uInt maxPixels) const

Help the user pick a cursor for most efficient access.

virtual uInt maximumCacheSize() const

Maximum size - not necessarily all used. In pixels.

virtual void setMaximumCacheSize (uInt howManyPixels)

Set the maximum (allowed) cache size as indicated.

virtual void setCacheSizeFromPath (const IPosition& sliceShape, const IPosition& windowStart, const IPosition& windowLength, const IPosition& axisPath)

Set the cache size as to "fit" the indicated path.

virtual void setCacheSizeInTiles (uInt howManyTiles)

Set the actual cache size for this Array to be be big enough for the indicated number of tiles. This cache is not shared with PagedArrays in other rows and is always clipped to be less than the maximum value set using the setMaximumCacheSize member function. tiles. Tiles are cached using a first in first out algorithm.

virtual void clearCache()

Clears and frees up the caches, but the maximum allowed cache size is unchanged from when setCacheSize was called

virtual void showCacheStatistics (ostream& os) const

Report on cache success.

virtual Bool ok() const

Check for symmetry in data members.

virtual const LatticeRegion* getRegionPtr() const

Get the region used (it always returns 0).

virtual Bool doGetSlice (Array<T>& buffer, const Slicer& theSlice)

Function which extracts an array from the map.

virtual void doPutSlice (const Array<T>& sourceBuffer, const IPosition& where, const IPosition& stride)

Function to replace the values in the map with soureBuffer.