def fetch(self, zoom_level, x, y):
#first, try to find the tile at this zoom level
#if we don't then that means somewhere above us in the tree is a leaf node
#find that leaf node and return its image
curs = self.conn.cursor()
#print '===================='
#print zoom_level, x, y
node_ids = []
for z in range(zoom_level, -1, -1):
#print z, x, y
node_ids.append(tiletree.build_node_id(z, x, y))
x = int(math.floor(x/2.0))
y = int(math.floor(y/2.0))
id_clause = ' OR '.join('nodes.node_id = %s' for id in node_ids)
curs.execute(\
"""
SELECT images.img_bytes
FROM %(node_table)s nodes, %(image_table)s images
WHERE images.image_id = nodes.image_id AND (%(id_clause)s) AND
(nodes.zoom_level = %%s OR (nodes.is_leaf and (nodes.is_full or nodes.is_blank)))
ORDER BY nodes.zoom_level DESC
""" % {'node_table':self.node_table, 'image_table':self.image_table,
'id_clause':id_clause,}, node_ids + [zoom_level] )
result = curs.fetchone()
if(result):
return StringIO.StringIO(result[0])
raise tiletree.TileNotFoundException()
def build_image(self, surface, node):
img_bytes = StringIO.StringIO()
img_id = tiletree.build_node_id(node.zoom_level, node.tile_x,
node.tile_y)
surface.write_to_png(img_bytes)
img_bytes = tiletree.palette_png_bytes(
StringIO.StringIO(img_bytes.getvalue()))
return (img_id, img_bytes)
def fetch_helper(self, zoom_level, x, y, layers, fetch_func, do_palette=True): cache_id = self.compute_layer_key(layers) + str(tiletree.build_node_id(zoom_level, x, y)) png_bytes = self.cache.get(cache_id) if(png_bytes == None): png_byte_stream = fetch_func(zoom_level, x, y, layers, do_palette) self.cache.set(cache_id, png_byte_stream.getvalue()) return png_byte_stream return StringIO.StringIO(png_bytes)
def fetch_helper(self,
zoom_level,
x,
y,
layers,
fetch_func,
do_palette=True):
cache_id = self.compute_layer_key(layers) + str(
tiletree.build_node_id(zoom_level, x, y))
png_bytes = self.cache.get(cache_id)
if (png_bytes == None):
png_byte_stream = fetch_func(zoom_level, x, y, layers, do_palette)
self.cache.set(cache_id, png_byte_stream.getvalue())
return png_byte_stream
return StringIO.StringIO(png_bytes)
def fetch_info(self, zoom_level, x, y): #first, try to find the tile at this zoom level #if we don't then that means somewhere above us in the tree is a leaf node curs = self.conn.cursor() for z in range(zoom_level, -1, -1): node_id = tiletree.build_node_id(z, x, y) curs.execute(\ """ SELECT nodes.is_blank, nodes.is_full, nodes.is_leaf, nodes.metadata FROM %s nodes WHERE nodes.node_id = %%s """ % (self.node_table,), (node_id,) ) result = curs.fetchone() if(result): return result x = int(math.floor(x/2.0)) y = int(math.floor(y/2.0)) raise tiletree.TileNotFoundException()
def build_image(self, surface, node): img_bytes = StringIO.StringIO() img_id = tiletree.build_node_id(node.zoom_level, node.tile_x, node.tile_y) surface.write_to_png(img_bytes) img_bytes = tiletree.palette_png_bytes(StringIO.StringIO(img_bytes.getvalue())) return (img_id, img_bytes)
