def __init__(self, host_list=None, styles = {}, stop = None, max_jobs=1000, lifetime=3600):
GearmanWorker.__init__(self, host_list)
self.maps = {}
self.prj = {}
self.stop = stop
self.max_jobs = max_jobs
self.done = 0
self.lifetime = lifetime
self.started = time.time()
# Projects between tile pixel co-ordinates and LatLong (EPSG:4326)
self.tileproj = SphericalProjection(MAX_ZOOM)
for style in styles:
logging.debug("Creating map object for %s using %s" % (style, styles[style]))
m = mapnik.Map(TILE_SIZE, TILE_SIZE)
self.maps[style] = m
# Load XML style
mapnik.load_map(m, styles[style], True)
# Obtain <Map> projection
self.prj[style] = mapnik.Projection(m.srs)
self.register_task("render_" + style, render_job);
class Renderer(GearmanWorker):
def __init__(self, host_list=None, styles = {}, stop = None, max_jobs=1000, lifetime=3600):
GearmanWorker.__init__(self, host_list)
self.maps = {}
self.prj = {}
self.stop = stop
self.max_jobs = max_jobs
self.done = 0
self.lifetime = lifetime
self.started = time.time()
# Projects between tile pixel co-ordinates and LatLong (EPSG:4326)
self.tileproj = SphericalProjection(MAX_ZOOM)
for style in styles:
logging.debug("Creating map object for %s using %s" % (style, styles[style]))
m = mapnik.Map(TILE_SIZE, TILE_SIZE)
self.maps[style] = m
# Load XML style
mapnik.load_map(m, styles[style], True)
# Obtain <Map> projection
self.prj[style] = mapnik.Projection(m.srs)
self.register_task("render_" + style, render_job);
def after_poll(self, any_activity):
if self.stop.is_set():
logging.debug("Caught stop signal")
return False
if self.done >= self.max_jobs:
logging.debug("Max jobs limit exceeded, stopping")
return False
if time.time() - self.started > self.lifetime:
logging.debug("Max worker lifetime exceeded, stopping")
return False
return True
def render_image(self, style, m, x, y, z):
# Calculate the meta tile size to use for this zoom level
size = min(METATILE, 1 << z)
# Calculate pixel positions of bottom-left & top-right
p0 = (x * TILE_SIZE, (y + size) * TILE_SIZE)
p1 = ((x + size) * TILE_SIZE, y * TILE_SIZE)
# Convert to LatLong (EPSG:4326)
l0 = self.tileproj.fromPixelToLL(p0, z);
l1 = self.tileproj.fromPixelToLL(p1, z);
# Convert to map projection (e.g. mercator co-ords EPSG:900913)
c0 = self.prj[style].forward(mapnik.Coord(l0[0], l0[1]))
c1 = self.prj[style].forward(mapnik.Coord(l1[0], l1[1]))
# Bounding box for the meta-tile
bbox = mapnik.Envelope(c0.x,c0.y, c1.x,c1.y)
meta_size = TILE_SIZE * size
m.resize(meta_size, meta_size)
m.zoom_to_box(bbox)
if(m.buffer_size == 0):
m.buffer_size = 128
im = mapnik.Image(meta_size, meta_size);
mapnik.render(m, im)
return im
def render_job(self, job):
(style, x, y, z) = json.loads(job.data)
t = MetaTile(style, x, y, z)
logging.info("Got job: %s", t.to_string())
try:
m = self.maps[style]
except KeyError:
logging.error("No map for '%s'", style)
self.send_job_failure(job)
return
try:
im = self.render_image(style, m, x, y, z)
size = min(METATILE, 1 << z)
for xx in range(size):
for yy in range(size):
view = im.view(xx * TILE_SIZE , yy * TILE_SIZE, TILE_SIZE, TILE_SIZE)
tile = view.tostring('png256:z=3')
t.write_tile(xx, yy, tile)
except Exception, e:
logging.critical(e)
self.send_job_failure(job)
return
logging.info("Completed: %s", t.to_string())
self.done += 1
return t.getvalue()
