# Procedures to split rivers of a raster fill into small enough blocks.
# Last edited on 2021-07-28 12:09:45 by jstolfi

import raster_splitrivers_IMP

def doit(OPHS, Delta, Gamma):
  # Assumes that the parameter {OPHS} is a list of oriented paths, each
  # consisting of a single trace, all parallel to some unit direction
  # vector {xdir}.
  # 
  # Also assumes that the paths have been classified into /rivers/ as
  # define in the paper by E. Santos et al. (2021). e.g. by
  # {raster_regroupp.split_at_forks}. The procedure will split each
  # river (group) into smaller /sections/ by horizontal /cut-lines/ that
  # run between scan-lines. Then it will re-assign the group indices
  # (consecutively, starting from 0) to identify these sections, even 
  # if none of the original groups was split.
  #
  # The paths in {OPHS} must be pairwise disjoint. They must be sorted
  # in /scanline order/, which is defined by increasing projection on an
  # axis {ydir} perpendicular to {xdir}, ignoring roundoff errors; with
  # ties broken by increasing projection along {xdir}. The orientations
  # of the paths and traces are ignored by these procedures.
  #
  # This procedure uses the contact information of each path as accessed
  # by {path_hp.get_contacts} and {path_hp.set_contacts}. These lists
  # must have all contacts which have both sides on paths of {OPHS}, and
  # only those. Contacts between {OPHS} and other paths (such as
  # contours) should not be in those lists.
  return raster_splitrivers_IMP.doir(OPHS, Delta, Gamma)