def process(self):
'''
Starts loading the next section.
'''
# do nothing while workers are not available
if self._active_workers.full():
return
#
# here we have at least 1 worker available
#
#
# viewing has higher priority, so check if we have anything
# in the viewing queue
#
if len(self._viewing_queue) != 0:
for view in self._viewing_queue:
# check if we have the tiles required for this view
allLoaded = True
for tile in view._tiles:
if tile._status.isVirgin():
# we need to load this tile
tile._status.loading()
self._loading_queue.append(tile)
allLoaded = False
print 'We need tile', tile
elif tile._status.isLoading():
# the tile is still loading
allLoaded = False
if allLoaded:
#
# we have all the tiles and
# now we can stitch the view
#
self._viewing_queue.remove(view)
view._status.loading()
print 'Stitching', view
# now it is time to calculate the bounding box for this view
bbox = View.calculateBB(view._tiles, view._zoomlevel)
# print bbox
view._bbox = bbox # re-attach the bounding box (since something could have changed)
# allocate shared mem for view
memory = mp.RawArray(ctypes.c_ubyte, bbox[1]*bbox[3])
view._memory = memory # we need to keep a reference
view._imagedata = Stitcher.shmem_as_ndarray(memory)
# start worker
args = (self, view)
worker = mp.Process(target=Stitcher.run, args=args)
self._active_workers.put(1) # increase worker counter
worker.start()
#
# loading has lower priority
# check if we have anything in the loading queue
#
if len(self._loading_queue) != 0:
tile = self._loading_queue.pop(0)
#zoomlevels = [0, 1, 2, 3, 4, 5] # TODO dynamically
# allocate shared mem for tile and for each zoom level
for z in self._zoomlevels:
divisor = 2**z
tile_width = tile._bbox[1] / divisor
tile_height = tile._bbox[3] / divisor # TODO maybe int?
memory = mp.RawArray(ctypes.c_ubyte, tile_width*tile_height)
imagedata = Loader.shmem_as_ndarray(memory)
tile._levels.append(Level(memory, imagedata))
# start worker
args = (self, tile)
worker = mp.Process(target=Loader.run, args=args)
self._active_workers.put(1) # increase worker counter
worker.start()
return # jump out
