def gen_tasks(self):
"""
Generator returning a tiles coordinates to render
@todo: Replace naive implementation with collision detection
:return: (zoom, x, y)
"""
for zoom in range(MIN_ZOOM, MAX_ZOOM + 1):
seen = set() # (x, y)
M = 2**zoom - 1
# Find all areas suitable for zoom
for area in Area.objects.filter(is_active=True,
min_zoom__lte=zoom,
max_zoom__gte=zoom):
# Get area tiles
SW = ll_to_xy(zoom, area.SW)
NE = ll_to_xy(zoom, area.NE)
left = max(SW[0] - PAD_TILES, 0)
right = min(NE[0] + PAD_TILES, M)
top = max(NE[1] - PAD_TILES, 0)
bottom = min(SW[1] + PAD_TILES, M)
a_size = (right - left + 1) * (bottom - top + 1)
self.log("Checking area '%s' at zoom level %d "\
" (%d x %d = %d tiles)" % (area.name, zoom,
right - left + 1,
bottom - top + 1,
a_size))
seen |= set((tc.x, tc.y) for tc in TileCache.objects.filter(
map=self.map.id, zoom=zoom).only("x", "y"))
for x in range(left, right + 1):
for y in range(top, bottom + 1):
c = (x, y)
if c in seen:
continue
seen.add(c)
if not self.force:
# Check tile is ready
tc = TileCache.objects.filter(map=self.map.id,
zoom=zoom,
x=x,
y=y).first()
if tc and tc.ready:
continue
yield (zoom, x, y)
def test_zero_point(zoom_level):
C = ll_to_xy(zoom_level, (0, 0))
assert C == (2**(zoom_level - 1), 2**(zoom_level - 1))