//
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// Copyright 2005-2007 Adobe Systems Incorporated
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//
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// Distributed under the Boost Software License, Version 1.0
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// See accompanying file LICENSE_1_0.txt or copy at
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// http://www.boost.org/LICENSE_1_0.txt
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//
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#ifndef BOOST_GIL_VIRTUAL_LOCATOR_HPP
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#define BOOST_GIL_VIRTUAL_LOCATOR_HPP
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#include <boost/gil/dynamic_step.hpp>
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#include <boost/gil/position_iterator.hpp>
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#include <boost/assert.hpp>
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#include <boost/iterator/iterator_facade.hpp>
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namespace boost { namespace gil {
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/// \ingroup PixelLocatorModel PixelBasedModel
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/// \brief A 2D locator over a virtual image
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/// Upon dereferencing, invokes a given function object passing it its coordinates.
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/// Models:
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/// PixelLocatorConcept,
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/// HasDynamicXStepTypeConcept,
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/// HasDynamicYStepTypeConcept,
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/// HasTransposedTypeConcept
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///
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/// \tparam DerefFn Function object that given a point returns a reference.
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/// Models PixelDereferenceAdaptorConcept.
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/// \tparam IsTransposed Indicates if locator should navigate in transposed mode.
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template <typename DerefFn, bool IsTransposed>
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class virtual_2d_locator
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: public pixel_2d_locator_base
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<
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virtual_2d_locator<DerefFn, IsTransposed>,
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position_iterator<DerefFn, IsTransposed>,
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position_iterator<DerefFn, 1-IsTransposed>
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>
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{
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using this_t = virtual_2d_locator<DerefFn, IsTransposed>;
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public:
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using parent_t = pixel_2d_locator_base
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<
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virtual_2d_locator<DerefFn, IsTransposed>,
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position_iterator<DerefFn, IsTransposed>,
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position_iterator<DerefFn, 1-IsTransposed>
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>;
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using const_t = virtual_2d_locator<typename DerefFn::const_t, IsTransposed>;
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using deref_fn_t = DerefFn;
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using point_t = typename parent_t::point_t;
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using coord_t = typename parent_t::coord_t;
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using x_coord_t = typename parent_t::x_coord_t;
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using y_coord_t = typename parent_t::y_coord_t;
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using x_iterator = typename parent_t::x_iterator;
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using y_iterator = typename parent_t::y_iterator;
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template <typename NewDerefFn>
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struct add_deref
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{
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using type = virtual_2d_locator<deref_compose<NewDerefFn, DerefFn>, IsTransposed>;
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static type make(this_t const& loc, NewDerefFn const& new_deref_fn)
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{
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return type(loc.pos(), loc.step(),
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deref_compose<NewDerefFn, DerefFn>(new_deref_fn, loc.deref_fn()));
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}
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};
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virtual_2d_locator(
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point_t const& p = {0, 0},
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point_t const& step = {1, 1},
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deref_fn_t const& deref_fn = deref_fn_t())
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: y_pos_(p, step, deref_fn)
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{}
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template <typename D, bool TR>
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virtual_2d_locator(virtual_2d_locator<D, TR> const &loc, coord_t y_step)
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: y_pos_(loc.pos(), point_t(loc.step().x, loc.step().y * y_step), loc.deref_fn())
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{}
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template <typename D, bool TR>
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virtual_2d_locator(virtual_2d_locator<D, TR> const& loc, coord_t x_step, coord_t y_step, bool transpose = false)
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: y_pos_(loc.pos()
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, transpose ?
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point_t(loc.step().x * y_step, loc.step().y * x_step) :
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point_t(loc.step().x * x_step, loc.step().y * y_step)
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, loc.deref_fn())
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{
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BOOST_ASSERT(transpose == (IsTransposed != TR));
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}
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template <typename D, bool TR>
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virtual_2d_locator(virtual_2d_locator<D, TR> const& other) : y_pos_(other.y_pos_) {}
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virtual_2d_locator(virtual_2d_locator const& other) : y_pos_(other.y_pos_) {}
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virtual_2d_locator& operator=(virtual_2d_locator const& other) = default;
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bool operator==(const this_t& p) const { return y_pos_ == p.y_pos_; }
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auto x() -> x_iterator&
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{
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return *gil_reinterpret_cast<x_iterator*>(this);
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}
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auto x() const -> x_iterator const&
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{
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return *gil_reinterpret_cast_c<x_iterator const*>(this);
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}
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auto y() -> y_iterator& { return y_pos_; }
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auto y() const -> y_iterator const& { return y_pos_; }
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/// Returns the y distance between two x_iterators given the difference of their x positions
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auto y_distance_to(this_t const& it2, x_coord_t) const -> y_coord_t
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{
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return (it2.pos()[1 - IsTransposed] - pos()[1 - IsTransposed])
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/ step()[1 - IsTransposed];
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}
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/// \todo TODO: is there no gap at the end of each row?
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/// i.e. can we use x_iterator to visit every pixel instead of nested loops?
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bool is_1d_traversable(x_coord_t) const { return false; }
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// Methods specific for virtual 2D locator
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auto pos() const -> point_t const& { return y_pos_.pos(); }
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auto step() const -> point_t const& { return y_pos_.step(); }
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auto deref_fn() const -> deref_fn_t const& { return y_pos_.deref_fn(); }
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private:
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template <typename D, bool TR>
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friend class virtual_2d_locator;
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y_iterator y_pos_; // current position, the step and the dereference object
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};
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/////////////////////////////
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// PixelBasedConcept
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/////////////////////////////
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template <typename D, bool TR>
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struct channel_type<virtual_2d_locator<D, TR>>
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: channel_type<typename virtual_2d_locator<D, TR>::parent_t>
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{
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};
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template <typename D, bool TR>
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struct color_space_type<virtual_2d_locator<D, TR>>
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: color_space_type<typename virtual_2d_locator<D, TR>::parent_t>
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{
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};
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template <typename D, bool TR>
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struct channel_mapping_type<virtual_2d_locator<D, TR>>
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: channel_mapping_type<typename virtual_2d_locator<D, TR>::parent_t>
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{
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};
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template <typename D, bool TR>
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struct is_planar<virtual_2d_locator<D, TR>>
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: is_planar<typename virtual_2d_locator<D, TR>::parent_t>
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{
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};
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/////////////////////////////
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// HasDynamicXStepTypeConcept
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/////////////////////////////
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template <typename D, bool TR>
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struct dynamic_x_step_type<virtual_2d_locator<D,TR>>
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{
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using type = virtual_2d_locator<D,TR>;
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};
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/////////////////////////////
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// HasDynamicYStepTypeConcept
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/////////////////////////////
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template <typename D, bool TR>
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struct dynamic_y_step_type<virtual_2d_locator<D,TR>>
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{
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using type = virtual_2d_locator<D,TR>;
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};
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/////////////////////////////
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// HasTransposedTypeConcept
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/////////////////////////////
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template <typename D, bool IsTransposed>
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struct transposed_type<virtual_2d_locator<D,IsTransposed>>
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{
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using type = virtual_2d_locator<D,1-IsTransposed>;
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};
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}} // namespace boost::gil
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#endif
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