/* | |
Copyright 2005-2007 Adobe Systems Incorporated | |
Use, modification and distribution are subject to the Boost Software License, | |
Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at | |
http://www.boost.org/LICENSE_1_0.txt). | |
See http://opensource.adobe.com/gil for most recent version including documentation. | |
*/ | |
/*************************************************************************************************/ | |
#ifndef GIL_LOCATOR_H | |
#define GIL_LOCATOR_H | |
//////////////////////////////////////////////////////////////////////////////////////// | |
/// \file | |
/// \brief pixel 2D locator | |
/// \author Lubomir Bourdev and Hailin Jin \n | |
/// Adobe Systems Incorporated | |
/// \date 2005-2007 \n September 20, 2006 | |
/// | |
//////////////////////////////////////////////////////////////////////////////////////// | |
#include <cstddef> | |
#include <cassert> | |
#include "pixel_iterator.hpp" | |
//////////////////////////////////////////////////////////////////////////////////////// | |
/// Pixel 2D LOCATOR | |
//////////////////////////////////////////////////////////////////////////////////////// | |
namespace boost { namespace gil { | |
//forward declarations | |
template <typename P> ptrdiff_t memunit_step(const P*); | |
template <typename P> P* memunit_advanced(const P* p, ptrdiff_t diff); | |
template <typename P> P& memunit_advanced_ref(P* p, ptrdiff_t diff); | |
template <typename Iterator, typename D> struct iterator_add_deref; | |
template <typename T> class point2; | |
namespace detail { | |
// helper class specialized for each axis of pixel_2d_locator | |
template <std::size_t D, typename Loc> class locator_axis; | |
} | |
template <typename T> struct dynamic_x_step_type; | |
template <typename T> struct dynamic_y_step_type; | |
template <typename T> struct channel_type; | |
template <typename T> struct color_space_type; | |
template <typename T> struct channel_mapping_type; | |
template <typename T> struct is_planar; | |
template <typename T> struct num_channels; | |
// The type of a locator or a view that has X and Y swapped. By default it is the same | |
template <typename T> struct transposed_type { | |
typedef T type; | |
}; | |
/// \class pixel_2d_locator_base | |
/// \brief base class for models of PixelLocatorConcept | |
/// \ingroup PixelLocatorModel PixelBasedModel | |
/// | |
/// Pixel locator is similar to a pixel iterator, but allows for 2D navigation of pixels within an image view. | |
/// It has a 2D difference_type and supports random access operations like: | |
/// \code | |
/// difference_type offset2(2,3); | |
/// locator+=offset2; | |
/// locator[offset2]=my_pixel; | |
/// \endcode | |
/// | |
/// In addition, each coordinate acts as a random-access iterator that can be modified separately: | |
/// "++locator.x()" or "locator.y()+=10" thereby moving the locator horizontally or vertically. | |
/// | |
/// It is called a locator because it doesn't implement the complete interface of a random access iterator. | |
/// For example, increment and decrement operations don't make sense (no way to specify dimension). | |
/// Also 2D difference between two locators cannot be computed without knowledge of the X position within the image. | |
/// | |
/// This base class provides most of the methods and typedefs needed to create a model of a locator. GIL provides two | |
/// locator models as subclasses of \p pixel_2d_locator_base. A memory-based locator, \p memory_based_2d_locator and a virtual | |
/// locator, \p virtual_2d_locator. | |
/// The minimum functionality a subclass must provide is this: | |
/// \code | |
/// class my_locator : public pixel_2d_locator_base<my_locator, ..., ...> { // supply the types for x-iterator and y-iterator | |
/// typedef ... const_t; // read-only locator | |
/// | |
/// template <typename Deref> struct add_deref { | |
/// typedef ... type; // locator that invokes the Deref dereference object upon pixel access | |
/// static type make(const my_locator& loc, const Deref& d); | |
/// }; | |
/// | |
/// my_locator(); | |
/// my_locator(const my_locator& pl); | |
/// | |
/// // constructors with dynamic step in y (and x). Only valid for locators with dynamic steps | |
/// my_locator(const my_locator& loc, coord_t y_step); | |
/// my_locator(const my_locator& loc, coord_t x_step, coord_t y_step, bool transpose); | |
/// | |
/// bool operator==(const my_locator& p) const; | |
/// | |
/// // return _references_ to horizontal/vertical iterators. Advancing them moves this locator | |
/// x_iterator& x(); | |
/// y_iterator& y(); | |
/// x_iterator const& x() const; | |
/// y_iterator const& y() const; | |
/// | |
/// // return the vertical distance to another locator. Some models need the horizontal distance to compute it | |
/// y_coord_t y_distance_to(const my_locator& loc2, x_coord_t xDiff) const; | |
/// | |
/// // return true iff incrementing an x-iterator located at the last column will position it at the first | |
/// // column of the next row. Some models need the image width to determine that. | |
/// bool is_1d_traversable(x_coord_t width) const; | |
/// }; | |
/// \endcode | |
/// | |
/// Models may choose to override some of the functions in the base class with more efficient versions. | |
/// | |
template <typename Loc, typename XIterator, typename YIterator> // The concrete subclass, the X-iterator and the Y-iterator | |
class pixel_2d_locator_base { | |
public: | |
typedef XIterator x_iterator; | |
typedef YIterator y_iterator; | |
// typedefs required by ConstRandomAccessNDLocatorConcept | |
static const std::size_t num_dimensions=2; | |
typedef typename std::iterator_traits<x_iterator>::value_type value_type; | |
typedef typename std::iterator_traits<x_iterator>::reference reference; // result of dereferencing | |
typedef typename std::iterator_traits<x_iterator>::difference_type coord_t; // 1D difference type (same for all dimensions) | |
typedef point2<coord_t> difference_type; // result of operator-(locator,locator) | |
typedef difference_type point_t; | |
template <std::size_t D> struct axis { | |
typedef typename detail::locator_axis<D,Loc>::coord_t coord_t; | |
typedef typename detail::locator_axis<D,Loc>::iterator iterator; | |
}; | |
// typedefs required by ConstRandomAccess2DLocatorConcept | |
typedef typename point_t::template axis<0>::coord_t x_coord_t; | |
typedef typename point_t::template axis<1>::coord_t y_coord_t; | |
bool operator!=(const Loc& p) const { return !(concrete()==p); } | |
x_iterator x_at(x_coord_t dx, y_coord_t dy) const { Loc tmp=concrete(); tmp+=point_t(dx,dy); return tmp.x(); } | |
x_iterator x_at(const difference_type& d) const { Loc tmp=concrete(); tmp+=d; return tmp.x(); } | |
y_iterator y_at(x_coord_t dx, y_coord_t dy) const { Loc tmp=concrete(); tmp+=point_t(dx,dy); return tmp.y(); } | |
y_iterator y_at(const difference_type& d) const { Loc tmp=concrete(); tmp+=d; return tmp.y(); } | |
Loc xy_at(x_coord_t dx, y_coord_t dy) const { Loc tmp=concrete(); tmp+=point_t(dx,dy); return tmp; } | |
Loc xy_at(const difference_type& d) const { Loc tmp=concrete(); tmp+=d; return tmp; } | |
template <std::size_t D> typename axis<D>::iterator& axis_iterator() { return detail::locator_axis<D,Loc>()(concrete()); } | |
template <std::size_t D> typename axis<D>::iterator const& axis_iterator() const { return detail::locator_axis<D,Loc>()(concrete()); } | |
template <std::size_t D> typename axis<D>::iterator axis_iterator(const point_t& p) const { return detail::locator_axis<D,Loc>()(concrete(),p); } | |
reference operator()(x_coord_t dx, y_coord_t dy) const { return *x_at(dx,dy); } | |
reference operator[](const difference_type& d) const { return *x_at(d.x,d.y); } | |
reference operator*() const { return *concrete().x(); } | |
Loc& operator+=(const difference_type& d) { concrete().x()+=d.x; concrete().y()+=d.y; return concrete(); } | |
Loc& operator-=(const difference_type& d) { concrete().x()-=d.x; concrete().y()-=d.y; return concrete(); } | |
Loc operator+(const difference_type& d) const { return xy_at(d); } | |
Loc operator-(const difference_type& d) const { return xy_at(-d); } | |
// Some locators can cache 2D coordinates for faster subsequent access. By default there is no caching | |
typedef difference_type cached_location_t; | |
cached_location_t cache_location(const difference_type& d) const { return d; } | |
cached_location_t cache_location(x_coord_t dx, y_coord_t dy)const { return difference_type(dx,dy); } | |
private: | |
Loc& concrete() { return (Loc&)*this; } | |
const Loc& concrete() const { return (const Loc&)*this; } | |
template <typename X> friend class pixel_2d_locator; | |
}; | |
// helper classes for each axis of pixel_2d_locator_base | |
namespace detail { | |
template <typename Loc> | |
class locator_axis<0,Loc> { | |
typedef typename Loc::point_t point_t; | |
public: | |
typedef typename point_t::template axis<0>::coord_t coord_t; | |
typedef typename Loc::x_iterator iterator; | |
inline iterator& operator()( Loc& loc) const { return loc.x(); } | |
inline iterator const& operator()(const Loc& loc) const { return loc.x(); } | |
inline iterator operator()( Loc& loc, const point_t& d) const { return loc.x_at(d); } | |
inline iterator operator()(const Loc& loc, const point_t& d) const { return loc.x_at(d); } | |
}; | |
template <typename Loc> | |
class locator_axis<1,Loc> { | |
typedef typename Loc::point_t point_t; | |
public: | |
typedef typename point_t::template axis<1>::coord_t coord_t; | |
typedef typename Loc::y_iterator iterator; | |
inline iterator& operator()( Loc& loc) const { return loc.y(); } | |
inline iterator const& operator()(const Loc& loc) const { return loc.y(); } | |
inline iterator operator()( Loc& loc, const point_t& d) const { return loc.y_at(d); } | |
inline iterator operator()(const Loc& loc, const point_t& d) const { return loc.y_at(d); } | |
}; | |
} | |
template <typename Loc, typename XIt, typename YIt> | |
struct channel_type<pixel_2d_locator_base<Loc,XIt,YIt> > : public channel_type<XIt> {}; | |
template <typename Loc, typename XIt, typename YIt> | |
struct color_space_type<pixel_2d_locator_base<Loc,XIt,YIt> > : public color_space_type<XIt> {}; | |
template <typename Loc, typename XIt, typename YIt> | |
struct channel_mapping_type<pixel_2d_locator_base<Loc,XIt,YIt> > : public channel_mapping_type<XIt> {}; | |
template <typename Loc, typename XIt, typename YIt> | |
struct is_planar<pixel_2d_locator_base<Loc,XIt,YIt> > : public is_planar<XIt> {}; | |
/// \class memory_based_2d_locator | |
/// \brief Memory-based pixel locator. Models: PixelLocatorConcept,HasDynamicXStepTypeConcept,HasDynamicYStepTypeConcept,HasTransposedTypeConcept | |
/// \ingroup PixelLocatorModel PixelBasedModel | |
/// | |
/// The class takes a step iterator as a parameter. The step iterator provides navigation along the vertical axis | |
/// while its base iterator provides horizontal navigation. | |
/// | |
/// Each instantiation is optimal in terms of size and efficiency. | |
/// For example, xy locator over interleaved rgb image results in a step iterator consisting of | |
/// one std::ptrdiff_t for the row size and one native pointer (8 bytes total). ++locator.x() resolves to pointer | |
/// increment. At the other extreme, a 2D navigation of the even pixels of a planar CMYK image results in a step | |
/// iterator consisting of one std::ptrdiff_t for the doubled row size, and one step iterator consisting of | |
/// one std::ptrdiff_t for the horizontal step of two and a CMYK planar_pixel_iterator consisting of 4 pointers (24 bytes). | |
/// In this case ++locator.x() results in four native pointer additions. | |
/// | |
/// Note also that \p memory_based_2d_locator does not require that its element type be a pixel. It could be | |
/// instantiated with an iterator whose \p value_type models only \p Regular. In this case the locator | |
/// models the weaker RandomAccess2DLocatorConcept, and does not model PixelBasedConcept. | |
/// Many generic algorithms don't require the elements to be pixels. | |
//////////////////////////////////////////////////////////////////////////////////////// | |
template <typename StepIterator> | |
class memory_based_2d_locator : public pixel_2d_locator_base<memory_based_2d_locator<StepIterator>, typename iterator_adaptor_get_base<StepIterator>::type, StepIterator> { | |
typedef memory_based_2d_locator<StepIterator> this_t; | |
GIL_CLASS_REQUIRE(StepIterator, boost::gil, StepIteratorConcept) | |
public: | |
typedef pixel_2d_locator_base<memory_based_2d_locator<StepIterator>, typename iterator_adaptor_get_base<StepIterator>::type, StepIterator> parent_t; | |
typedef memory_based_2d_locator<typename const_iterator_type<StepIterator>::type> const_t; // same as this type, but over const values | |
typedef typename parent_t::coord_t coord_t; | |
typedef typename parent_t::x_coord_t x_coord_t; | |
typedef typename parent_t::y_coord_t y_coord_t; | |
typedef typename parent_t::x_iterator x_iterator; | |
typedef typename parent_t::y_iterator y_iterator; | |
typedef typename parent_t::difference_type difference_type; | |
typedef typename parent_t::reference reference; | |
template <typename Deref> struct add_deref { | |
typedef memory_based_2d_locator<typename iterator_add_deref<StepIterator,Deref>::type> type; | |
static type make(const memory_based_2d_locator<StepIterator>& loc, const Deref& nderef) { | |
return type(iterator_add_deref<StepIterator,Deref>::make(loc.y(),nderef)); | |
} | |
}; | |
memory_based_2d_locator() {} | |
memory_based_2d_locator(const StepIterator& yit) : _p(yit) {} | |
template <typename SI> memory_based_2d_locator(const memory_based_2d_locator<SI>& loc, coord_t y_step) : _p(loc.x(), loc.row_size()*y_step) {} | |
template <typename SI> memory_based_2d_locator(const memory_based_2d_locator<SI>& loc, coord_t x_step, coord_t y_step, bool transpose=false) | |
: _p(make_step_iterator(loc.x(),(transpose ? loc.row_size() : loc.pixel_size())*x_step), | |
(transpose ? loc.pixel_size() : loc.row_size())*y_step ) {} | |
memory_based_2d_locator(x_iterator xit, std::ptrdiff_t row_bytes) : _p(xit,row_bytes) {} | |
template <typename X> memory_based_2d_locator(const memory_based_2d_locator<X>& pl) : _p(pl._p) {} | |
memory_based_2d_locator(const memory_based_2d_locator& pl) : _p(pl._p) {} | |
bool operator==(const this_t& p) const { return _p==p._p; } | |
x_iterator const& x() const { return _p.base(); } | |
y_iterator const& y() const { return _p; } | |
x_iterator& x() { return _p.base(); } | |
y_iterator& y() { return _p; } | |
// These are faster versions of functions already provided in the superclass | |
x_iterator x_at (x_coord_t dx, y_coord_t dy) const { return memunit_advanced(x(), offset(dx,dy)); } | |
x_iterator x_at (const difference_type& d) const { return memunit_advanced(x(), offset(d.x,d.y)); } | |
this_t xy_at (x_coord_t dx, y_coord_t dy) const { return this_t(x_at( dx , dy ), row_size()); } | |
this_t xy_at (const difference_type& d) const { return this_t(x_at( d.x, d.y), row_size()); } | |
reference operator()(x_coord_t dx, y_coord_t dy) const { return memunit_advanced_ref(x(),offset(dx,dy)); } | |
reference operator[](const difference_type& d) const { return memunit_advanced_ref(x(),offset(d.x,d.y)); } | |
this_t& operator+=(const difference_type& d) { memunit_advance(x(),offset(d.x,d.y)); return *this; } | |
this_t& operator-=(const difference_type& d) { memunit_advance(x(),offset(-d.x,-d.y)); return *this; } | |
// Memory-based locators can have 1D caching of 2D relative coordinates | |
typedef std::ptrdiff_t cached_location_t; // type used to store relative location (to allow for more efficient repeated access) | |
cached_location_t cache_location(const difference_type& d) const { return offset(d.x,d.y); } | |
cached_location_t cache_location(x_coord_t dx, y_coord_t dy)const { return offset(dx,dy); } | |
reference operator[](const cached_location_t& loc) const { return memunit_advanced_ref(x(),loc); } | |
// Only make sense for memory-based locators | |
std::ptrdiff_t row_size() const { return memunit_step(y()); } // distance in mem units (bytes or bits) between adjacent rows | |
std::ptrdiff_t pixel_size() const { return memunit_step(x()); } // distance in mem units (bytes or bits) between adjacent pixels on the same row | |
bool is_1d_traversable(x_coord_t width) const { return row_size()-pixel_size()*width==0; } // is there no gap at the end of each row? | |
// Returns the vertical distance (it2.y-it1.y) between two x_iterators given the difference of their x positions | |
std::ptrdiff_t y_distance_to(const this_t& p2, x_coord_t xDiff) const { | |
std::ptrdiff_t rowDiff=memunit_distance(x(),p2.x())-pixel_size()*xDiff; | |
assert(( rowDiff % row_size())==0); | |
return rowDiff / row_size(); | |
} | |
private: | |
template <typename X> friend class memory_based_2d_locator; | |
std::ptrdiff_t offset(x_coord_t x, y_coord_t y) const { return y*row_size() + x*pixel_size(); } | |
StepIterator _p; | |
}; | |
///////////////////////////// | |
// PixelBasedConcept | |
///////////////////////////// | |
template <typename SI> | |
struct color_space_type<memory_based_2d_locator<SI> > : public color_space_type<typename memory_based_2d_locator<SI>::parent_t> { | |
}; | |
template <typename SI> | |
struct channel_mapping_type<memory_based_2d_locator<SI> > : public channel_mapping_type<typename memory_based_2d_locator<SI>::parent_t> { | |
}; | |
template <typename SI> | |
struct is_planar<memory_based_2d_locator<SI> > : public is_planar<typename memory_based_2d_locator<SI>::parent_t> { | |
}; | |
template <typename SI> | |
struct channel_type<memory_based_2d_locator<SI> > : public channel_type<typename memory_based_2d_locator<SI>::parent_t> { | |
}; | |
///////////////////////////// | |
// HasDynamicXStepTypeConcept | |
///////////////////////////// | |
// Take the base iterator of SI (which is typically a step iterator) and change it to have a step in x | |
template <typename SI> | |
struct dynamic_x_step_type<memory_based_2d_locator<SI> > { | |
private: | |
typedef typename iterator_adaptor_get_base<SI>::type base_iterator_t; | |
typedef typename dynamic_x_step_type<base_iterator_t>::type base_iterator_step_t; | |
typedef typename iterator_adaptor_rebind<SI, base_iterator_step_t>::type dynamic_step_base_t; | |
public: | |
typedef memory_based_2d_locator<dynamic_step_base_t> type; | |
}; | |
///////////////////////////// | |
// HasDynamicYStepTypeConcept | |
///////////////////////////// | |
template <typename SI> | |
struct dynamic_y_step_type<memory_based_2d_locator<SI> > { | |
typedef memory_based_2d_locator<SI> type; | |
}; | |
} } // namespace boost::gil | |
#endif |