Hold mathematical expressions involving ImageInterface objects. More...

#include <ImageExpr.h>

Inheritance diagram for casa::ImageExpr< T >:

Public Member Functions
	ImageExpr ()
	The default constructor.
	ImageExpr (const LatticeExpr< T > &latticeExpr, const String &name)
	Construct an ImageExpr from a LatticeExpr.
	ImageExpr (const ImageExpr< T > &other)
	Copy constructor (reference semantics)
	~ImageExpr ()
	Destructor does nothing.
ImageExpr< T > &	operator= (const ImageExpr< T > &other)
	Assignment (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	isMasked () const
	Has the object really a mask?
virtual const LatticeRegion *	getRegionPtr () const
	Get the region used.
virtual IPosition	shape () const
	return the shape of the ImageExpr
virtual void	resize (const TiledShape &newShape)
	Function which changes the shape of the ImageExpr.
virtual Bool	doGetMaskSlice (Array< Bool > &buffer, const Slicer &section)
	Do the actual get of the mask data.
virtual Bool	doGetSlice (Array< T > &buffer, const Slicer &theSlice)
	Do the actual get of the data.
virtual void	doPutSlice (const Array< T > &sourceBuffer, const IPosition &where, const IPosition &stride)
	putSlice is not possible on an expression, so it throws an exception.
virtual String	name (Bool stripPath=False) const
	Return the name of the current ImageInterface object.
virtual Bool	ok () const
	Check class invariants.
virtual LatticeIterInterface< T > *	makeIter (const LatticeNavigator &navigator, Bool useRef) const
	These are the implementations of the LatticeIterator letters.
virtual Bool	isWritable () const
	Returns False, as the ImageExpr is not writable.
virtual IPosition	doNiceCursorShape (uInt maxPixels) const
	Help the user pick a cursor for most efficient access if they only want pixel values and don't care about the order or dimension of the cursor.
virtual Bool	lock (FileLocker::LockType, uInt nattempts)
	Handle the (un)locking and syncing.
virtual void	unlock ()
virtual Bool	hasLock (FileLocker::LockType) const
virtual void	resync ()
	Resynchronize the Lattice object with the lattice file.
virtual void	tempClose ()
	Temporarily close the lattice.
virtual void	reopen ()
	Explicitly reopen the temporarily closed lattice.
const LatticeExpr< T > &	expression () const
	Get the lattice expression.
Private Attributes
LatticeExpr< T >	latticeExpr_p
Unit	unit_p
Lattice< Bool > *	pBool_p
	These are used to return null object by reference.
Record	rec_p
String	name_p

Detailed Description

template<class T>
class casa::ImageExpr< T >

Hold mathematical expressions involving ImageInterface objects.

Intended use:

Public interface

Review Status

Test programs:: tImageExpr

Prerequisite

Etymology

This class holds a LatticeExpr object but inherits from ImageInterface hence ImageExpr

Synopsis

An ImageExpr object holds a LatticeExpr object which can be used to evaluate mathematical expressions involving Lattices. ImageExpr exists so that direct manipulation of LatticeExpr objects by methods expecting an ImageInterface, rather than a Lattice can occur.

The ImageExpr object is constructed from a LatticeExpr object, but only if the latter has true Coordinates associated with it. The ImageExpr object is not writable, so the ImageExpr object functions like a read only ImageInterface.

Example

       PagedImage<Float> a("imageB");                // Open PagedImages
       PagedImage<Float> b("imageB");
   
       LatticeExprNode node(a+b);                    // Create ImageExpr
       LatticeExpr<Float> lExpr(node);
       ImageExpr<Float> iExpr(lExpr);
   
       LogOrigin or("imageImpl", "main()", WHERE);   // Create statistics object
       LogIO logger(or);
       ImageStatistics<Float> stats(iExpr, logger);
       Bool ok = stats.display();                              // Display statistics

The ImageExpr object is evaluated during the call to stats.dislay(). Previously, the expression tree has been constructed, but not evaluated.

Motivation

This enables one to evaluate expressions but not to have to write them out to an output image.

Definition at line 109 of file ImageExpr.h.

Constructor & Destructor Documentation

template<class T>

casa::ImageExpr< T >::ImageExpr ( )

The default constructor.

template<class T>

casa::ImageExpr< T >::ImageExpr	(	const LatticeExpr< T > &	latticeExpr,
		const String &	name
	)

Construct an ImageExpr from a LatticeExpr.

The name given could be the original expression string. The prefix "Expression: " is added to the name if not empty. The function name() returns this name (including possible prefix).

template<class T>

casa::ImageExpr< T >::ImageExpr ( const ImageExpr< T > & other )

Copy constructor (reference semantics)

template<class T>

casa::ImageExpr< T >::~ImageExpr ( )

Destructor does nothing.

Member Function Documentation

template<class T>

virtual ImageInterface<T>* casa::ImageExpr< T >::cloneII ( ) const [virtual]

Make a copy of the object (reference semantics).

Implements casa::ImageInterface< T >.

template<class T>

virtual Bool casa::ImageExpr< T >::doGetMaskSlice	(	Array< Bool > &	buffer,
		const Slicer &	section
	)		`[virtual]`

Do the actual get of the mask data.

The return value is always False, thus the buffer does not reference another array.

Reimplemented from casa::MaskedLattice< T >.

template<class T>

virtual Bool casa::ImageExpr< T >::doGetSlice	(	Array< T > &	buffer,
		const Slicer &	theSlice
	)		`[virtual]`

Do the actual get of the data.

Implements casa::Lattice< T >.

template<class T>

virtual IPosition casa::ImageExpr< T >::doNiceCursorShape ( uInt maxPixels ) const [virtual]

Help the user pick a cursor for most efficient access if they only want pixel values and don't care about the order or dimension of the cursor.

Reimplemented from casa::LatticeBase.

template<class T>

virtual void casa::ImageExpr< T >::doPutSlice	(	const Array< T > &	sourceBuffer,
		const IPosition &	where,
		const IPosition &	stride
	)		`[virtual]`

putSlice is not possible on an expression, so it throws an exception.

Implements casa::Lattice< T >.

template<class T>

const LatticeExpr<T>& casa::ImageExpr< T >::expression ( ) const [inline]

Get the lattice expression.

Definition at line 194 of file ImageExpr.h.

template<class T>

virtual const LatticeRegion* casa::ImageExpr< T >::getRegionPtr ( ) const [virtual]

Get the region used.

Implements casa::MaskedLattice< T >.

template<class T>

virtual Bool casa::ImageExpr< T >::hasLock ( FileLocker::LockType ) const [virtual]

Reimplemented from casa::LatticeBase.

template<class T>

virtual String casa::ImageExpr< T >::imageType ( ) const [virtual]

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

Implements casa::ImageInterface< T >.

template<class T>

virtual Bool casa::ImageExpr< T >::isMasked ( ) const [virtual]

Has the object really a mask?

Reimplemented from casa::MaskedLattice< T >.

template<class T>

virtual Bool casa::ImageExpr< T >::isWritable ( ) const [virtual]

Returns False, as the ImageExpr is not writable.

Reimplemented from casa::LatticeBase.

template<class T>

virtual Bool casa::ImageExpr< T >::lock	(	FileLocker::LockType	,
		uInt	nattempts
	)		`[virtual]`

Handle the (un)locking and syncing.

Reimplemented from casa::LatticeBase.

template<class T>

virtual LatticeIterInterface<T>* casa::ImageExpr< T >::makeIter	(	const LatticeNavigator &	navigator,
		Bool	useRef
	)		const `[virtual]`

These are the implementations of the LatticeIterator letters.

Note: not for public use

Reimplemented from casa::Lattice< T >.

template<class T>

virtual String casa::ImageExpr< T >::name ( Bool stripPath = False ) const [virtual]

Return the name of the current ImageInterface object.

Returns the expression string given in the constructor.

Implements casa::ImageInterface< T >.

template<class T>

virtual Bool casa::ImageExpr< T >::ok ( ) const [virtual]

Check class invariants.

Implements casa::ImageInterface< T >.

template<class T>

ImageExpr<T>& casa::ImageExpr< T >::operator= ( const ImageExpr< T > & other )

Assignment (reference semantics)

template<class T>

virtual void casa::ImageExpr< T >::reopen ( ) [virtual]

Explicitly reopen the temporarily closed lattice.

By default the function does not do anything at all.

Reimplemented from casa::LatticeBase.

template<class T>

virtual void casa::ImageExpr< T >::resize ( const TiledShape & newShape ) [virtual]

Function which changes the shape of the ImageExpr.

Throws an exception as ImageExpr is not writable.

Implements casa::ImageInterface< T >.

template<class T>

virtual void casa::ImageExpr< T >::resync ( ) [virtual]

Resynchronize the Lattice object with the lattice file.

This function is only useful if no read-locking is used, ie. if the table lock option is UserNoReadLocking or AutoNoReadLocking. In that cases the table system does not acquire a read-lock, thus does not synchronize itself automatically.
By default the function does not do anything at all.

Reimplemented from casa::LatticeBase.

template<class T>

virtual IPosition casa::ImageExpr< T >::shape ( ) const [virtual]

return the shape of the ImageExpr

Implements casa::LatticeBase.

template<class T>

virtual void casa::ImageExpr< T >::tempClose ( ) [virtual]

Temporarily close the lattice.

It will be reopened automatically on the next access.
By default the function does not do anything at all.

Reimplemented from casa::LatticeBase.

template<class T>

virtual void casa::ImageExpr< T >::unlock ( ) [virtual]