rasterio inspired block_windows implementation using itertools

block_windows.py

from itertools import product, chain

def block_windows(src, xsize, ysize):
     height, width = src.shape
     nrows, rmod = divmod(height, ysize)
     ncols, cmod = divmod(width, xsize)
     offsets = product(range(0, width, xsize), range(0, height, ysize))
     sizes = product(chain([xsize]*ncols, [cmod]), chain([ysize]*nrows, [rmod]))
     for (xoff, yoff), (xsize, ysize) in zip(offsets, sizes):
         yield xoff, yoff, xsize, ysize