Rectangle

Include <mln/core/se/rect2d.hpp>

struct rect2d : public mln::se_facade<rect2d>

Define a dynamic rectangular window anchored at (0,0). Its width and height are always odd numbers to ensure symmetry.

Public Functions

rect2d() = default

Construct an empty rectangle.

rect2d(int width, int height)

Construct a rectangle of size (Width × Height).

Parameters:

• width – The width of the rectangle. If width is even, it is rounded to the closest lower odd int.

• height – The height of the rectangle. If height is even, it is rounded to the closest lower odd int.

rect2d inc() const

A WNeighborhood to be added when used incrementally.

rect2d dec() const

A WNeighborhood to be substracted when used incrementally.

inline auto offsets() const

Return a range of SE offsets.

bool is_decomposable() const

Return true if decomposable (for any non-empty rectangle)

bool is_separable() const

Return true if separable (for any non-empty rectangle)

bool is_incremental() const

Return true if incremental (if the width is larger than 1)

std::vector<periodic_line2d> decompose() const

Return an horizontal line of length Width and a vertical line of length Height corresponding to the SE decomposition.

std::vector<periodic_line2d> separate() const

Return an horizontal line of length Width and a vertical line of length Height.

int radial_extent() const

Return the extent radius.

mln::box2d compute_input_region(mln::box2d roi) const

Compute the input region of a ROI.

mln::box2d compute_output_region(mln::box2d roi) const

Compute the output region of a ROI.

Performance

The rectangle is decomposable in two lines, so that the speed of a dilation (or erosion) by a rectangle does not depend on the size of the rectangle.

Example 1. Dilation by rectangle

#include <mln/core/se/rect2d.hpp>

mln::se::rect2d (21, 21);
auto output = mln::morpho::structural::dilate(input, rect);