240 lines
11 KiB
C++
240 lines
11 KiB
C++
//
|
|
// Copyright 2005-2007 Adobe Systems Incorporated
|
|
//
|
|
// Distributed under 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
|
|
//
|
|
#ifndef BOOST_GIL_IMAGE_VIEW_HPP
|
|
#define BOOST_GIL_IMAGE_VIEW_HPP
|
|
|
|
#include <boost/gil/dynamic_step.hpp>
|
|
#include <boost/gil/iterator_from_2d.hpp>
|
|
|
|
#include <cstddef>
|
|
#include <iterator>
|
|
|
|
namespace boost { namespace gil {
|
|
|
|
////////////////////////////////////////////////////////////////////////////////////////
|
|
/// \class image_view
|
|
/// \ingroup ImageViewModel PixelBasedModel
|
|
/// \brief A lightweight object that interprets memory as a 2D array of pixels. Models ImageViewConcept,PixelBasedConcept,HasDynamicXStepTypeConcept,HasDynamicYStepTypeConcept,HasTransposedTypeConcept
|
|
///
|
|
/// Image view consists of a pixel 2D locator (defining the mechanism for navigating in 2D)
|
|
/// and the image dimensions.
|
|
///
|
|
/// Image views to images are what ranges are to STL containers. They are lightweight objects,
|
|
/// that don't own the pixels. It is the user's responsibility that the underlying data remains
|
|
/// valid for the lifetime of the image view.
|
|
///
|
|
/// Similar to iterators and ranges, constness of views does not extend to constness of pixels.
|
|
/// A const \p image_view does not allow changing its location in memory (resizing, moving) but does
|
|
/// not prevent one from changing the pixels. The latter requires an image view whose value_type
|
|
/// is const.
|
|
///
|
|
/// Images have interfaces consistent with STL 1D random access containers, so they can be used
|
|
/// directly in STL algorithms like:
|
|
/// \code
|
|
/// std::fill(img.begin(), img.end(), red_pixel);
|
|
/// \endcode
|
|
///
|
|
/// In addition, horizontal, vertical and 2D random access iterators are provided.
|
|
///
|
|
/// Note also that \p image_view does not require that its element type be a pixel. It could be
|
|
/// instantiated with a locator whose \p value_type models only \p Regular. In this case the image
|
|
/// view models the weaker RandomAccess2DImageViewConcept, and does not model PixelBasedConcept.
|
|
/// Many generic algorithms don't require the elements to be pixels.
|
|
///
|
|
////////////////////////////////////////////////////////////////////////////////////////
|
|
template <typename Loc> // Models 2D Pixel Locator
|
|
class image_view {
|
|
public:
|
|
|
|
// aliases required by ConstRandomAccessNDImageViewConcept
|
|
static const std::size_t num_dimensions=2;
|
|
using value_type = typename Loc::value_type;
|
|
using reference = typename Loc::reference; // result of dereferencing
|
|
using coord_t = typename Loc::coord_t; // 1D difference type (same for all dimensions)
|
|
using difference_type = coord_t; // result of operator-(1d_iterator,1d_iterator)
|
|
using point_t = typename Loc::point_t;
|
|
using locator = Loc;
|
|
using const_t = image_view<typename Loc::const_t>; // same as this type, but over const values
|
|
template <std::size_t D> struct axis
|
|
{
|
|
using coord_t = typename Loc::template axis<D>::coord_t; // difference_type along each dimension
|
|
using iterator = typename Loc::template axis<D>::iterator; // 1D iterator type along each dimension
|
|
};
|
|
using iterator = iterator_from_2d<Loc>; // 1D iterator type for each pixel left-to-right inside top-to-bottom
|
|
using const_iterator = typename const_t::iterator; // may be used to examine, but not to modify values
|
|
using const_reference = typename const_t::reference; // behaves as a const reference
|
|
using pointer = typename std::iterator_traits<iterator>::pointer; // behaves as a pointer to the value type
|
|
using reverse_iterator = std::reverse_iterator<iterator>;
|
|
using size_type = std::size_t;
|
|
|
|
// aliases required by ConstRandomAccess2DImageViewConcept
|
|
using xy_locator = locator;
|
|
using x_iterator = typename xy_locator::x_iterator; // pixel iterator along a row
|
|
using y_iterator = typename xy_locator::y_iterator; // pixel iterator along a column
|
|
using x_coord_t = typename xy_locator::x_coord_t;
|
|
using y_coord_t = typename xy_locator::y_coord_t;
|
|
|
|
template <typename Deref> struct add_deref
|
|
{
|
|
using type = image_view<typename Loc::template add_deref<Deref>::type>;
|
|
static type make(const image_view<Loc>& iv, const Deref& d)
|
|
{
|
|
return type(iv.dimensions(), Loc::template add_deref<Deref>::make(iv.pixels(),d));
|
|
}
|
|
};
|
|
|
|
image_view() : _dimensions(0,0) {}
|
|
template <typename View> image_view(const View& iv) : _dimensions(iv.dimensions()), _pixels(iv.pixels()) {}
|
|
|
|
template <typename L2> image_view(const point_t& sz , const L2& loc) : _dimensions(sz), _pixels(loc) {}
|
|
template <typename L2> image_view(coord_t width, coord_t height, const L2& loc) : _dimensions(x_coord_t(width),y_coord_t(height)), _pixels(loc) {}
|
|
|
|
template <typename View> image_view& operator=(const View& iv) { _pixels=iv.pixels(); _dimensions=iv.dimensions(); return *this; }
|
|
image_view& operator=(const image_view& iv) { _pixels=iv.pixels(); _dimensions=iv.dimensions(); return *this; }
|
|
|
|
template <typename View> bool operator==(const View& v) const { return pixels()==v.pixels() && dimensions()==v.dimensions(); }
|
|
template <typename View> bool operator!=(const View& v) const { return !(*this==v); }
|
|
|
|
template <typename L2> friend void swap(image_view<L2>& x, image_view<L2>& y);
|
|
|
|
/// \brief Exchanges the elements of the current view with those of \a other
|
|
/// in constant time.
|
|
///
|
|
/// \note Required by the Collection concept
|
|
/// \see https://www.boost.org/libs/utility/Collection.html
|
|
void swap(image_view<Loc>& other)
|
|
{
|
|
using boost::gil::swap;
|
|
swap(*this, other);
|
|
}
|
|
|
|
/// \brief Returns true if the view has no elements, false otherwise.
|
|
///
|
|
/// \note Required by the Collection concept
|
|
/// \see https://www.boost.org/libs/utility/Collection.html
|
|
bool empty() const { return !(width() > 0 && height() > 0); }
|
|
|
|
/// \brief Returns a reference to the first element in raster order.
|
|
///
|
|
/// \note Required by the ForwardCollection, since view model the concept.
|
|
/// \see https://www.boost.org/libs/utility/Collection.html
|
|
reference front() const { return *begin(); }
|
|
|
|
/// \brief Returns a reference to the last element in raster order.
|
|
///
|
|
/// \note Required by the ForwardCollection, since view model the concept.
|
|
/// \see https://www.boost.org/libs/utility/Collection.html
|
|
reference back() const { return *rbegin(); }
|
|
|
|
const point_t& dimensions() const { return _dimensions; }
|
|
const locator& pixels() const { return _pixels; }
|
|
x_coord_t width() const { return dimensions().x; }
|
|
y_coord_t height() const { return dimensions().y; }
|
|
std::size_t num_channels() const { return gil::num_channels<value_type>::value; }
|
|
bool is_1d_traversable() const { return _pixels.is_1d_traversable(width()); }
|
|
|
|
//\{@
|
|
/// \name 1D navigation
|
|
size_type size() const { return width()*height(); }
|
|
iterator begin() const { return iterator(_pixels,_dimensions.x); }
|
|
iterator end() const { return begin()+(difference_type)size(); } // potential performance problem!
|
|
reverse_iterator rbegin() const { return reverse_iterator(end()); }
|
|
reverse_iterator rend() const { return reverse_iterator(begin()); }
|
|
reference operator[](difference_type i) const { return begin()[i]; } // potential performance problem!
|
|
iterator at(difference_type i)const { return begin()+i; }
|
|
iterator at(const point_t& p) const { return begin()+p.y*width()+p.x; }
|
|
iterator at(x_coord_t x, y_coord_t y)const { return begin()+y*width()+x; }
|
|
|
|
//\}@
|
|
|
|
//\{@
|
|
/// \name 2-D navigation
|
|
reference operator()(const point_t& p) const { return _pixels(p.x,p.y); }
|
|
reference operator()(x_coord_t x, y_coord_t y)const { return _pixels(x,y); }
|
|
template <std::size_t D> typename axis<D>::iterator axis_iterator(const point_t& p) const { return _pixels.template axis_iterator<D>(p); }
|
|
xy_locator xy_at(x_coord_t x, y_coord_t y) const { return _pixels+point_t(x_coord_t(x),y_coord_t(y)); }
|
|
locator xy_at(const point_t& p) const { return _pixels+p; }
|
|
//\}@
|
|
|
|
//\{@
|
|
/// \name X navigation
|
|
x_iterator x_at(x_coord_t x, y_coord_t y) const { return _pixels.x_at(x,y); }
|
|
x_iterator x_at(const point_t& p) const { return _pixels.x_at(p); }
|
|
x_iterator row_begin(y_coord_t y) const { return x_at(0,y); }
|
|
x_iterator row_end(y_coord_t y) const { return x_at(width(),y); }
|
|
//\}@
|
|
|
|
//\{@
|
|
/// \name Y navigation
|
|
y_iterator y_at(x_coord_t x, y_coord_t y) const { return xy_at(x,y).y(); }
|
|
y_iterator y_at(const point_t& p) const { return xy_at(p).y(); }
|
|
y_iterator col_begin(x_coord_t x) const { return y_at(x,0); }
|
|
y_iterator col_end(x_coord_t x) const { return y_at(x,height()); }
|
|
//\}@
|
|
|
|
private:
|
|
template <typename L2> friend class image_view;
|
|
|
|
point_t _dimensions;
|
|
xy_locator _pixels;
|
|
};
|
|
|
|
template <typename L2>
|
|
inline void swap(image_view<L2>& x, image_view<L2>& y) {
|
|
using std::swap;
|
|
swap(x._dimensions,y._dimensions);
|
|
swap(x._pixels, y._pixels); // TODO: Extend further
|
|
}
|
|
|
|
/////////////////////////////
|
|
// PixelBasedConcept
|
|
/////////////////////////////
|
|
|
|
template <typename L>
|
|
struct channel_type<image_view<L> > : public channel_type<L> {};
|
|
|
|
template <typename L>
|
|
struct color_space_type<image_view<L> > : public color_space_type<L> {};
|
|
|
|
template <typename L>
|
|
struct channel_mapping_type<image_view<L> > : public channel_mapping_type<L> {};
|
|
|
|
template <typename L>
|
|
struct is_planar<image_view<L> > : public is_planar<L> {};
|
|
|
|
/////////////////////////////
|
|
// HasDynamicXStepTypeConcept
|
|
/////////////////////////////
|
|
|
|
template <typename L>
|
|
struct dynamic_x_step_type<image_view<L> > {
|
|
using type = image_view<typename dynamic_x_step_type<L>::type>;
|
|
};
|
|
|
|
/////////////////////////////
|
|
// HasDynamicYStepTypeConcept
|
|
/////////////////////////////
|
|
|
|
template <typename L>
|
|
struct dynamic_y_step_type<image_view<L> > {
|
|
using type = image_view<typename dynamic_y_step_type<L>::type>;
|
|
};
|
|
|
|
/////////////////////////////
|
|
// HasTransposedTypeConcept
|
|
/////////////////////////////
|
|
|
|
template <typename L>
|
|
struct transposed_type<image_view<L> > {
|
|
using type = image_view<typename transposed_type<L>::type>;
|
|
};
|
|
|
|
}} // namespace boost::gil
|
|
|
|
#endif
|