new_contents: # Copyright 2019 Luke Pinner
  # 
  # Licensed under the Apache License, Version 2.0 (the "License");
  # you may not use this file except in compliance with the License.
  # You may obtain a copy of the License at
  # 
  #     http://www.apache.org/licenses/LICENSE-2.0
  # 
  # Unless required by applicable law or agreed to in writing, software
  # distributed under the License is distributed on an "AS IS" BASIS,
  # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  # See the License for the specific language governing permissions and
  # limitations under the License.
  
  from itertools import product
  import rasterio as rio
  from rasterio import windows
  
  
  def overlapping_tiles(src, overlap, width, height, boundless=False):
      """"width & height not including overlap i.e requesting a 256x256 window with 
          1px overlap will return a 258x258 window (for non edge windows)"""
      offsets = product(range(0, src.meta['width'], width), range(0, src.meta['height'], height))
      big_window = windows.Window(col_off=0, row_off=0, width=src.meta['width'], height=src.meta['height'])
      for col_off, row_off in offsets:
  
          window = windows.Window(
              col_off=col_off - overlap,
              row_off=row_off - overlap,
              width=width + overlap * 2,
              height=height + overlap * 2)
  
          if boundless:
              yield window
          else:
              yield window.intersection(big_window)
  
  
  def overlapping_blocks(src, overlap=0, band=1, boundless=False):
  
      big_window = windows.Window(col_off=0, row_off=0, width=src.meta['width'], height=src.meta['height'])
      for ji, window in src.block_windows(band):
  
          if overlap == 0:
              yield window
  
          else:
              window = windows.Window(
                  col_off=window.col_off - overlap,
                  row_off=window.row_off - overlap,
                  width=window.width + overlap * 2,
                  height=window.height + overlap * 2)
              if boundless:
                  yield window
              else:
                  yield window.intersection(big_window)
  
subject: Create overlapping_windows.py