def format(self, mapobj, file_name="", fill=True):
"""The segmentation routines require a disk file to be used for paging
segments in and out of memory. This routine formats the file open for
write on file descriptor fd for use as a segment file.
"""
if file_name == "":
file_name = libgis.G_tempfile()
mapobj.temp_file = open(file_name, "w")
size = ctypes.sizeof(RTYPE[mapobj.mtype]["ctypes"])
if fill:
libseg.Segment_format(
mapobj.temp_file.fileno(),
self.rows(),
self.cols(),
self.srows,
self.scols,
size,
)
else:
libseg.Segment_format_nofill(
mapobj.temp_file.fileno(),
self.rows(),
self.cols(),
self.srows,
self.scols,
size,
)
# TODO: why should I close and then re-open it?
mapobj.temp_file.close()
def open(self, mapobj):
"""Open a segment it is necessary to pass a RasterSegment object.
"""
self.val = RTYPE[mapobj.mtype]['grass def']()
size = ctypes.sizeof(RTYPE[mapobj.mtype]['ctypes'])
file_name = libgis.G_tempfile()
libseg.Segment_open(self.c_seg, file_name, self.rows(), self.cols(),
self.srows, self.scols, size, self.nseg())
self.flush()
