* apps/graph-morpho/make_complex2d.hh (unmake_complex2d): New function. --- milena/ChangeLog | 7 ++++ milena/apps/graph-morpho/make_complex2d.hh | 42 +++++++++++++++++++++++++++- 2 files changed, 48 insertions(+), 1 deletions(-) diff --git a/milena/ChangeLog b/milena/ChangeLog index 23e901b..68b7d0c 100644 --- a/milena/ChangeLog +++ b/milena/ChangeLog @@ -1,5 +1,12 @@ 2009-09-21 Roland Levillain &lt;roland(a)lrde.epita.fr&gt; + Deconstruction of image2d-based complex images. + + * apps/graph-morpho/make_complex2d.hh (unmake_complex2d): + New function. + +2009-09-21 Roland Levillain &lt;roland(a)lrde.epita.fr&gt; + Reify the construction of image2d-based complex images. * apps/graph-morpho/make_complex2d.hh: New file. diff --git a/milena/apps/graph-morpho/make_complex2d.hh b/milena/apps/graph-morpho/make_complex2d.hh index 1859ab0..a79c798 100644 --- a/milena/apps/graph-morpho/make_complex2d.hh +++ b/milena/apps/graph-morpho/make_complex2d.hh @@ -37,7 +37,9 @@ The values set on "edge" sites and "square" sites are a conjunction of the values on the face of the adjacent faces of - immediate lower dimension. */ + immediate lower dimension. + + The converse operation is unmake_complex2d. */ template <typename I> inline mln_concrete(I) @@ -88,4 +90,42 @@ make_complex2d(const mln::Image<I>& input_) return output; } + +/** \brief Create an image of pixels from a binary 2D image + representing a cubical 2-complex by dividing the resolution of the + image \a input image by two. + + Basically, this is the converse of make_complex2d. */ +template <typename I> +inline +mln_concrete(I) +unmake_complex2d(const mln::Image<I>& input_) +{ + using namespace mln; + + const I& input = exact(input_); + // The input image must have an odd number of rows and columns. + mln_precondition(input.nrows() % 2 == 1); + mln_precondition(input.ncols() % 2 == 1); + + // Create a (morpher) image of the pixels of INPUT. + typedef image_if< const I, cplx2d::predicate_t > J; + J input_pixels = input | cplx2d::is_pixel; + + /* FIXME: The construction of OUTPUT is obvioulsy not generic, since + it expects I's domain to provide the interface of an mln::box2d. + There should be a static precondition on I at the beginning of + this function. */ + typedef mln_concrete(I) O; + // FIXME: This won't work if INPUT's domain does not start at (0,0). + O output(input.nrows() / 2 + 1, input.ncols() / 2 + 1); + + mln_piter(J) p_in(input_pixels.domain()); + mln_piter(O) p_out(output.domain()); + for_all_2(p_in, p_out) + output(p_out) = input(p_in); + return output; +} + + #endif // ! APPS_GRAPH_MORPHO_MAKE_COMPLEX2D_HH -- 1.6.4.2