A multi-dimensional iterator templated over image type that walks an image region and is specialized to keep track of its index location. More...
#include <itkImageRegionConstIteratorWithIndex.h>
Public Types | |
typedef TImage::AccessorFunctorType | AccessorFunctorType |
typedef TImage::AccessorType | AccessorType |
typedef TImage | ImageType |
typedef TImage::IndexType | IndexType |
typedef IndexType::IndexValueType | IndexValueType |
typedef TImage::InternalPixelType | InternalPixelType |
typedef TImage::OffsetType | OffsetType |
typedef OffsetType::OffsetValueType | OffsetValueType |
typedef TImage::PixelContainer | PixelContainer |
typedef PixelContainer::Pointer | PixelContainerPointer |
typedef TImage::PixelType | PixelType |
typedef TImage::RegionType | RegionType |
typedef ImageRegionConstIteratorWithIndex | Self |
typedef TImage::SizeType | SizeType |
typedef SizeType::SizeValueType | SizeValueType |
typedef ImageConstIteratorWithIndex < TImage > | Superclass |
Public Member Functions | |
Self | Begin (void) const |
Self | End (void) const |
PixelType | Get (void) const |
const IndexType & | GetIndex () const |
const RegionType & | GetRegion () const |
void | GoToBegin (void) |
void | GoToReverseBegin (void) |
ImageRegionConstIteratorWithIndex (const ImageConstIteratorWithIndex< TImage > &it) | |
ImageRegionConstIteratorWithIndex (const TImage *ptr, const RegionType ®ion) | |
ImageRegionConstIteratorWithIndex () | |
bool | IsAtEnd (void) const |
bool | IsAtReverseEnd (void) const |
bool | operator!= (const Self &it) const |
Self & | operator++ () |
bool | operator< (const Self &it) const |
bool | operator<= (const Self &it) const |
bool | operator== (const Self &it) const |
bool | operator> (const Self &it) const |
bool | operator>= (const Self &it) const |
bool | Remaining () |
const PixelType & | Value (void) const |
Self & | operator-- () |
void | SetIndex (const IndexType &ind) |
Static Public Member Functions | |
static unsigned int | GetImageDimension () |
Static Public Attributes | |
static const unsigned int | ImageDimension = TImage::ImageDimension |
Protected Attributes | |
const InternalPixelType * | m_Begin |
IndexType | m_BeginIndex |
const InternalPixelType * | m_End |
IndexType | m_EndIndex |
TImage::ConstWeakPointer | m_Image |
unsigned long | m_OffsetTable [ImageDimension+1] |
AccessorType | m_PixelAccessor |
AccessorFunctorType | m_PixelAccessorFunctor |
const InternalPixelType * | m_Position |
IndexType | m_PositionIndex |
RegionType | m_Region |
bool | m_Remaining |
A multi-dimensional iterator templated over image type that walks an image region and is specialized to keep track of its index location.
The "WithIndex" family of iteators was designed for algorithms that use both the values and locations of image pixels in calculations. Unlike ImageRegionIterator, which calculates an index only when requested, ImageRegionIteratorWithIndex maintains its index location as a member variable that is updated during increment and decrement operations. Iteration speed is penalized, but index queries become more efficient.
ImageRegionConstIteratorWithIndex is a multi-dimensional iterator, requiring more information be specified before the iterator can be used than conventional iterators. Whereas the std::vector::iterator from the STL only needs to be passed a pointer to establish the iterator, the multi-dimensional image iterator needs a pointer, the size of the buffer, the size of the region, the start index of the buffer, and the start index of the region. To gain access to this information, ImageRegionConstIteratorWithIndex holds a reference to the image over which it is traversing.
ImageRegionConstIteratorWithIndex assumes a particular layout of the image data. The is arranged in a 1D array as if it were [][][][slice][row][col] with Index[0] = col, Index[1] = row, Index[2] = slice, etc.
operator++ provides a simple syntax for walking around a region of a multidimensional image. operator++ iterates across a row, constraining the movement to within a region of image. When the iterator reaches the boundary of the region along a row, the iterator automatically wraps to the next row, starting at the first pixel in the row that is part of the region. This allows for simple processing loops of the form:
IteratorType it( image, image->GetRequestedRegion() );
it.Begin();
while( ! it.IsAtEnd() )
{
it.Set( 100.0 + it.Get() );
++it;
}
It also can be used for walking in the reverse direction like
IteratorType it( image, image->GetRequestedRegion() );
it.End();
while( !it.IsAtBegin() )
{
it.Set( 100.0 );
--it;
}
Definition at line 123 of file itkImageRegionConstIteratorWithIndex.h.
typedef TImage::AccessorFunctorType itk::ImageConstIteratorWithIndex< TImage >::AccessorFunctorType [inherited] |
Definition at line 132 of file itkImageConstIteratorWithIndex.h.
typedef TImage::AccessorType itk::ImageConstIteratorWithIndex< TImage >::AccessorType [inherited] |
Accessor type that convert data between internal and external representations.
Reimplemented in itk::ReflectiveImageRegionIterator< TImage >, itk::ImageIteratorWithIndex< TImage >, itk::ImageLinearIteratorWithIndex< TImage >, itk::ImageRandomIteratorWithIndex< TImage >, itk::ImageRandomNonRepeatingIteratorWithIndex< TImage >, itk::ImageRegionExclusionIteratorWithIndex< TImage >, itk::ImageRegionIteratorWithIndex< TImage >, itk::ImageSliceIteratorWithIndex< TImage >, and itk::ImageLinearIteratorWithIndex< TImageType >.
Definition at line 131 of file itkImageConstIteratorWithIndex.h.
typedef TImage itk::ImageRegionConstIteratorWithIndex< TImage >::ImageType |
Image typedef support. While this was already typdef'ed in the superclass it needs to be redone here for this subclass to compile properly with gcc. Note that we have to rescope Image back to itk::Image to that is it not confused with ImageIterator::Image.
Reimplemented from itk::ImageConstIteratorWithIndex< TImage >.
Reimplemented in itk::ImageRegionIteratorWithIndex< TImage >.
Definition at line 140 of file itkImageRegionConstIteratorWithIndex.h.
typedef TImage::IndexType itk::ImageRegionConstIteratorWithIndex< TImage >::IndexType |
Index typedef support. While this was already typdef'ed in the superclass it needs to be redone here for this subclass to compile properly with gcc. Note that we have to rescope Index back to itk::Index to that is it not confused with ImageIterator::Index.
Reimplemented from itk::ImageConstIteratorWithIndex< TImage >.
Reimplemented in itk::ImageRegionIteratorWithIndex< TImage >.
Definition at line 134 of file itkImageRegionConstIteratorWithIndex.h.
typedef IndexType::IndexValueType itk::ImageConstIteratorWithIndex< TImage >::IndexValueType [inherited] |
Reimplemented in itk::ReflectiveImageRegionIterator< TImage >, itk::ImageIteratorWithIndex< TImage >, itk::ImageLinearIteratorWithIndex< TImage >, itk::ImageRandomIteratorWithIndex< TImage >, itk::ImageRandomNonRepeatingIteratorWithIndex< TImage >, itk::ImageRegionExclusionIteratorWithIndex< TImage >, itk::ImageRegionIteratorWithIndex< TImage >, itk::ImageSliceIteratorWithIndex< TImage >, and itk::ImageLinearIteratorWithIndex< TImageType >.
Definition at line 105 of file itkImageConstIteratorWithIndex.h.
typedef TImage::InternalPixelType itk::ImageConstIteratorWithIndex< TImage >::InternalPixelType [inherited] |
Internal Pixel Type
Reimplemented in itk::ReflectiveImageRegionIterator< TImage >, itk::ImageIteratorWithIndex< TImage >, itk::ImageLinearIteratorWithIndex< TImage >, itk::ImageRandomIteratorWithIndex< TImage >, itk::ImageRandomNonRepeatingIteratorWithIndex< TImage >, itk::ImageRegionExclusionIteratorWithIndex< TImage >, itk::ImageRegionIteratorWithIndex< TImage >, itk::ImageSliceIteratorWithIndex< TImage >, and itk::ImageLinearIteratorWithIndex< TImageType >.
Definition at line 124 of file itkImageConstIteratorWithIndex.h.
typedef TImage::OffsetType itk::ImageConstIteratorWithIndex< TImage >::OffsetType [inherited] |
Type of the Offset taken from the image
Reimplemented in itk::ReflectiveImageRegionConstIterator< TImage >, itk::ReflectiveImageRegionIterator< TImage >, itk::ImageIteratorWithIndex< TImage >, itk::ImageLinearIteratorWithIndex< TImage >, itk::ImageRandomIteratorWithIndex< TImage >, itk::ImageRandomNonRepeatingIteratorWithIndex< TImage >, itk::ImageRegionExclusionIteratorWithIndex< TImage >, itk::ImageRegionIteratorWithIndex< TImage >, itk::ImageSliceIteratorWithIndex< TImage >, and itk::ImageLinearIteratorWithIndex< TImageType >.
Definition at line 135 of file itkImageConstIteratorWithIndex.h.
typedef OffsetType::OffsetValueType itk::ImageConstIteratorWithIndex< TImage >::OffsetValueType [inherited] |
Reimplemented in itk::ReflectiveImageRegionConstIterator< TImage >, itk::ReflectiveImageRegionIterator< TImage >, itk::ImageIteratorWithIndex< TImage >, itk::ImageLinearIteratorWithIndex< TImage >, itk::ImageRandomIteratorWithIndex< TImage >, itk::ImageRandomNonRepeatingIteratorWithIndex< TImage >, itk::ImageRegionExclusionIteratorWithIndex< TImage >, itk::ImageRegionIteratorWithIndex< TImage >, itk::ImageSliceIteratorWithIndex< TImage >, and itk::ImageLinearIteratorWithIndex< TImageType >.
Definition at line 136 of file itkImageConstIteratorWithIndex.h.
typedef TImage::PixelContainer itk::ImageRegionConstIteratorWithIndex< TImage >::PixelContainer |
PixelContainer typedef support. Used to refer to the container for the pixel data. While this was already typdef'ed in the superclass it needs to be redone here for this subclass to compile properly with gcc.
Reimplemented from itk::ImageConstIteratorWithIndex< TImage >.
Reimplemented in itk::ImageRegionIteratorWithIndex< TImage >.
Definition at line 145 of file itkImageRegionConstIteratorWithIndex.h.
typedef PixelContainer::Pointer itk::ImageRegionConstIteratorWithIndex< TImage >::PixelContainerPointer |
Reimplemented from itk::ImageConstIteratorWithIndex< TImage >.
Reimplemented in itk::ImageRegionIteratorWithIndex< TImage >.
Definition at line 146 of file itkImageRegionConstIteratorWithIndex.h.
typedef TImage::PixelType itk::ImageConstIteratorWithIndex< TImage >::PixelType [inherited] |
External Pixel Type
Reimplemented in itk::ReflectiveImageRegionIterator< TImage >, itk::ImageIteratorWithIndex< TImage >, itk::ImageLinearIteratorWithIndex< TImage >, itk::ImageRandomIteratorWithIndex< TImage >, itk::ImageRandomNonRepeatingIteratorWithIndex< TImage >, itk::ImageRegionExclusionIteratorWithIndex< TImage >, itk::ImageRegionIteratorWithIndex< TImage >, itk::ImageSliceIteratorWithIndex< TImage >, and itk::ImageLinearIteratorWithIndex< TImageType >.
Definition at line 127 of file itkImageConstIteratorWithIndex.h.
typedef TImage::RegionType itk::ImageRegionConstIteratorWithIndex< TImage >::RegionType |
Region typedef support. While this was already typdef'ed in the superclass it needs to be redone here for this subclass to compile properly with gcc. Note that we have to rescope Region back to itk::ImageRegion so that is it not confused with ImageIterator::Index.
Reimplemented from itk::ImageConstIteratorWithIndex< TImage >.
Reimplemented in itk::ImageRegionIteratorWithIndex< TImage >.
Definition at line 152 of file itkImageRegionConstIteratorWithIndex.h.
typedef ImageRegionConstIteratorWithIndex itk::ImageRegionConstIteratorWithIndex< TImage >::Self |
Standard class typedefs.
Reimplemented from itk::ImageConstIteratorWithIndex< TImage >.
Reimplemented in itk::ImageRegionIteratorWithIndex< TImage >.
Definition at line 127 of file itkImageRegionConstIteratorWithIndex.h.
typedef TImage::SizeType itk::ImageConstIteratorWithIndex< TImage >::SizeType [inherited] |
Size typedef support.
Reimplemented in itk::ReflectiveImageRegionIterator< TImage >, itk::ImageIteratorWithIndex< TImage >, itk::ImageLinearIteratorWithIndex< TImage >, itk::ImageRandomIteratorWithIndex< TImage >, itk::ImageRandomNonRepeatingIteratorWithIndex< TImage >, itk::ImageRegionExclusionConstIteratorWithIndex< TImage >, itk::ImageRegionExclusionIteratorWithIndex< TImage >, itk::ImageRegionIteratorWithIndex< TImage >, itk::ImageSliceIteratorWithIndex< TImage >, and itk::ImageLinearIteratorWithIndex< TImageType >.
Definition at line 108 of file itkImageConstIteratorWithIndex.h.
typedef SizeType::SizeValueType itk::ImageConstIteratorWithIndex< TImage >::SizeValueType [inherited] |
Reimplemented in itk::ReflectiveImageRegionIterator< TImage >, itk::ImageIteratorWithIndex< TImage >, itk::ImageLinearIteratorWithIndex< TImage >, itk::ImageRandomIteratorWithIndex< TImage >, itk::ImageRandomNonRepeatingIteratorWithIndex< TImage >, itk::ImageRegionExclusionIteratorWithIndex< TImage >, itk::ImageRegionIteratorWithIndex< TImage >, itk::ImageSliceIteratorWithIndex< TImage >, and itk::ImageLinearIteratorWithIndex< TImageType >.
Definition at line 109 of file itkImageConstIteratorWithIndex.h.
typedef ImageConstIteratorWithIndex<TImage> itk::ImageRegionConstIteratorWithIndex< TImage >::Superclass |
Reimplemented in itk::ImageRegionIteratorWithIndex< TImage >.
Definition at line 128 of file itkImageRegionConstIteratorWithIndex.h.
itk::ImageRegionConstIteratorWithIndex< TImage >::ImageRegionConstIteratorWithIndex | ( | ) | [inline] |
Default constructor. Needed since we provide a cast constructor.
Definition at line 155 of file itkImageRegionConstIteratorWithIndex.h.
itk::ImageRegionConstIteratorWithIndex< TImage >::ImageRegionConstIteratorWithIndex | ( | const TImage * | ptr, | |
const RegionType & | region | |||
) | [inline] |
Constructor establishes an iterator to walk a particular image and a particular region of that image.
Definition at line 159 of file itkImageRegionConstIteratorWithIndex.h.
itk::ImageRegionConstIteratorWithIndex< TImage >::ImageRegionConstIteratorWithIndex | ( | const ImageConstIteratorWithIndex< TImage > & | it | ) | [inline] |
Constructor that can be used to cast from an ImageIterator to an ImageRegionConstIteratorWithIndex. Many routines return an ImageIterator but for a particular task, you may want an ImageRegionConstIteratorWithIndex. Rather than provide overloaded APIs that return different types of Iterators, itk returns ImageIterators and uses constructors to cast from an ImageIterator to a ImageRegionConstIteratorWithIndex.
Definition at line 169 of file itkImageRegionConstIteratorWithIndex.h.
Self itk::ImageConstIteratorWithIndex< TImage >::Begin | ( | void | ) | const [inherited] |
Move an iterator to the beginning of the region.
Self itk::ImageConstIteratorWithIndex< TImage >::End | ( | void | ) | const [inherited] |
Move an iterator to the End of the region.
PixelType itk::ImageConstIteratorWithIndex< TImage >::Get | ( | void | ) | const [inline, inherited] |
Get the pixel value
Definition at line 237 of file itkImageConstIteratorWithIndex.h.
static unsigned int itk::ImageConstIteratorWithIndex< TImage >::GetImageDimension | ( | ) | [inline, static, inherited] |
Get the dimension (size) of the index.
Definition at line 156 of file itkImageConstIteratorWithIndex.h.
const IndexType& itk::ImageConstIteratorWithIndex< TImage >::GetIndex | ( | void | ) | const [inline, inherited] |
Get the index. This provides a read only reference to the index.
Definition at line 219 of file itkImageConstIteratorWithIndex.h.
Referenced by itk::ConstrainedRegionBasedLevelSetFunctionSharedData< TInputImage, TFeatureImage, TSingleData >::PopulateListImage(), and itk::Statistics::JointDomainImageToListAdaptor< TImage >::Search().
const RegionType& itk::ImageConstIteratorWithIndex< TImage >::GetRegion | ( | ) | const [inline, inherited] |
Get the region that this iterator walks. ImageIterators know the beginning and the end of the region of the image to iterate over.
Definition at line 224 of file itkImageConstIteratorWithIndex.h.
void itk::ImageConstIteratorWithIndex< TImage >::GoToBegin | ( | void | ) | [inherited] |
Move an iterator to the beginning of the region.
Reimplemented in itk::ReflectiveImageRegionConstIterator< TImage >, itk::ImageRandomConstIteratorWithIndex< TImage >, and itk::ImageRandomNonRepeatingConstIteratorWithIndex< TImage >.
Referenced by itk::ConstrainedRegionBasedLevelSetFunctionSharedData< TInputImage, TFeatureImage, TSingleData >::PopulateListImage(), and itk::Statistics::JointDomainImageToListAdaptor< TImage >::Search().
void itk::ImageConstIteratorWithIndex< TImage >::GoToReverseBegin | ( | void | ) | [inherited] |
Move an iterator to the End of the region.
bool itk::ImageConstIteratorWithIndex< TImage >::IsAtEnd | ( | void | ) | const [inline, inherited] |
Is the iterator at the end of the region?
Reimplemented in itk::ImageRandomConstIteratorWithIndex< TImage >, and itk::ImageRandomNonRepeatingConstIteratorWithIndex< TImage >.
Definition at line 267 of file itkImageConstIteratorWithIndex.h.
Referenced by itk::ConstrainedRegionBasedLevelSetFunctionSharedData< TInputImage, TFeatureImage, TSingleData >::PopulateListImage(), and itk::Statistics::JointDomainImageToListAdaptor< TImage >::Search().
bool itk::ImageConstIteratorWithIndex< TImage >::IsAtReverseEnd | ( | void | ) | const [inline, inherited] |
Is the iterator at the beginning of the region?
Definition at line 261 of file itkImageConstIteratorWithIndex.h.
bool itk::ImageConstIteratorWithIndex< TImage >::operator!= | ( | const Self & | it | ) | const [inline, inherited] |
Comparison operator. Two iterators are the same if they "point to" the same memory location
Definition at line 162 of file itkImageConstIteratorWithIndex.h.
Self& itk::ImageRegionConstIteratorWithIndex< TImage >::operator++ | ( | ) |
Increment (prefix) the fastest moving dimension of the iterator's index. This operator will constrain the iterator within the region (i.e. the iterator will automatically wrap from the end of the row of the region to the beginning of the next row of the region) up until the iterator tries to moves past the last pixel of the region. Here, the iterator will be set to be one pixel past the end of the region.
Self& itk::ImageRegionConstIteratorWithIndex< TImage >::operator-- | ( | ) |
Decrement (prefix) the fastest moving dimension of the iterator's index. This operator will constrain the iterator within the region (i.e. the iterator will automatically wrap from the beginning of the row of the region to the end of the previous row of the region) up until the iterator tries to moves past the first pixel of the region. Here, the iterator will be set to be one pixel past the beginning of the region.
bool itk::ImageConstIteratorWithIndex< TImage >::operator< | ( | const Self & | it | ) | const [inline, inherited] |
Comparison operator. An iterator is "less than" another if it "points to" a lower memory location.
Definition at line 190 of file itkImageConstIteratorWithIndex.h.
bool itk::ImageConstIteratorWithIndex< TImage >::operator<= | ( | const Self & | it | ) | const [inline, inherited] |
Comparison operator. An iterator is "less than" another if it "points to" a lower memory location.
Definition at line 180 of file itkImageConstIteratorWithIndex.h.
bool itk::ImageConstIteratorWithIndex< TImage >::operator== | ( | const Self & | it | ) | const [inline, inherited] |
Comparison operator. Two iterators are the same if they "point to" the same memory location
Definition at line 171 of file itkImageConstIteratorWithIndex.h.
bool itk::ImageConstIteratorWithIndex< TImage >::operator> | ( | const Self & | it | ) | const [inline, inherited] |
Comparison operator. An iterator is "greater than" another if it "points to" a higher location.
Definition at line 210 of file itkImageConstIteratorWithIndex.h.
bool itk::ImageConstIteratorWithIndex< TImage >::operator>= | ( | const Self & | it | ) | const [inline, inherited] |
Comparison operator. An iterator is "greater than" another if it "points to" a higher location.
Definition at line 200 of file itkImageConstIteratorWithIndex.h.
bool itk::ImageConstIteratorWithIndex< TImage >::Remaining | ( | ) | [inline, inherited] |
Are there data remainning in the region ?
Definition at line 273 of file itkImageConstIteratorWithIndex.h.
void itk::ImageConstIteratorWithIndex< TImage >::SetIndex | ( | const IndexType & | ind | ) | [inline, inherited] |
Set the index. No bounds checking is performed.
Definition at line 229 of file itkImageConstIteratorWithIndex.h.
const PixelType& itk::ImageConstIteratorWithIndex< TImage >::Value | ( | void | ) | const [inline, inherited] |
Return a const reference to the pixel This method will provide the fastest access to pixel data, but it will NOT support ImageAdaptors.
Definition at line 243 of file itkImageConstIteratorWithIndex.h.
const unsigned int itk::ImageConstIteratorWithIndex< TImage >::ImageDimension = TImage::ImageDimension [static, inherited] |
Dimension of the image the iterator walks. This constant is needed so functions that are templated over image iterator type (as opposed to being templated over pixel type and dimension) can have compile time access to the dimension of the image that the iterator walks.
Reimplemented in itk::ImageRandomNonRepeatingConstIteratorWithIndex< TImage >.
Definition at line 101 of file itkImageConstIteratorWithIndex.h.
const InternalPixelType* itk::ImageConstIteratorWithIndex< TImage >::m_Begin [protected, inherited] |
Definition at line 292 of file itkImageConstIteratorWithIndex.h.
IndexType itk::ImageConstIteratorWithIndex< TImage >::m_BeginIndex [protected, inherited] |
Definition at line 282 of file itkImageConstIteratorWithIndex.h.
const InternalPixelType* itk::ImageConstIteratorWithIndex< TImage >::m_End [protected, inherited] |
Definition at line 293 of file itkImageConstIteratorWithIndex.h.
IndexType itk::ImageConstIteratorWithIndex< TImage >::m_EndIndex [protected, inherited] |
Definition at line 283 of file itkImageConstIteratorWithIndex.h.
TImage::ConstWeakPointer itk::ImageConstIteratorWithIndex< TImage >::m_Image [protected, inherited] |
Definition at line 279 of file itkImageConstIteratorWithIndex.h.
unsigned long itk::ImageConstIteratorWithIndex< TImage >::m_OffsetTable[ImageDimension+1] [protected, inherited] |
Definition at line 289 of file itkImageConstIteratorWithIndex.h.
AccessorType itk::ImageConstIteratorWithIndex< TImage >::m_PixelAccessor [protected, inherited] |
Definition at line 297 of file itkImageConstIteratorWithIndex.h.
AccessorFunctorType itk::ImageConstIteratorWithIndex< TImage >::m_PixelAccessorFunctor [protected, inherited] |
Definition at line 298 of file itkImageConstIteratorWithIndex.h.
const InternalPixelType* itk::ImageConstIteratorWithIndex< TImage >::m_Position [protected, inherited] |
Definition at line 291 of file itkImageConstIteratorWithIndex.h.
Referenced by itk::ImageConstIteratorWithIndex< TImageType >::operator!=(), itk::ImageConstIteratorWithIndex< TImageType >::operator<(), itk::ImageConstIteratorWithIndex< TImageType >::operator<=(), itk::ImageConstIteratorWithIndex< TImageType >::operator==(), itk::ImageConstIteratorWithIndex< TImageType >::operator>(), and itk::ImageConstIteratorWithIndex< TImageType >::operator>=().
IndexType itk::ImageConstIteratorWithIndex< TImage >::m_PositionIndex [protected, inherited] |
Definition at line 281 of file itkImageConstIteratorWithIndex.h.
RegionType itk::ImageConstIteratorWithIndex< TImage >::m_Region [protected, inherited] |
Definition at line 287 of file itkImageConstIteratorWithIndex.h.
bool itk::ImageConstIteratorWithIndex< TImage >::m_Remaining [protected, inherited] |
Definition at line 295 of file itkImageConstIteratorWithIndex.h.