# Writing slice elements to an RP3-style text file.
# Last edited on 2021-09-30 13:11:23 by stolfi

import txt_write_IMP

def write(wr, OCRS, OPHS, CTS, Z, angle):
  # Writes to file handle {wr} a description of a single object slice at
  # nominal height {Z}, consisting of the contours {OCRS}, the filling
  # elements {OPHS}, the contacts {CTS}, and the link paths associated
  # to {OPHS},
  # 
  # ??? Describe the file format ???
  #
  # Each element {ocr} in the list {OCRS} (written as a line with the 'C'
  # code) must be a /contour/, a closed path without jumps that follows
  # the boundary of the slice. The contours must be properly oriented
  # and must have the same trace parameters.
  # 
  # Each element {oph} in the filling list {OPHS} (written as a line
  # with 'R' code) must be a /raster/, an oriented path with a single
  # trace move, whose axis makes the specified {angle} (in radians,
  # counterclockwise) with the horizontal. If rotated by {-angle}, these
  # rasters must fall on equally spaced horizontal scanlines, sorted in
  # scanline order (increasing {Y} with ties broken by {X}). All these
  # traces must have the same parameters, including the same nominal
  # width that should be equal to the spacing of the scanlines.
  #
  # Each raster {oph} is written out with the first endpoint being the
  # one that would be the leftmost one in the urotated view; but its
  # orientaton is recorded in the 'rbit' field of the line. The
  # procedure also writes in the 'R' line the 'group' index assocated to
  # {oph} by {path_hp.get_group}.
  # 
  # The procedure also writes a line with 'L' code for each pair of
  # rasters that have either a contact or a connecting link path. The
  # contacts of each element {oph} are obtained with
  # {path_hp.get_contacts}, and the links that end at each endpoint are
  # obtaned with {path.get_links(oph)} and
  # {path.get_links(path.rev(oph))} All the links are supposed to
  # have the same move parameters as the rasters.
  # 
  return txt_write_IMP.write(wr, OCRS, OPHS, CTS, Z, angle)