def change_zoom(self, zoom):
'''zoom in or out by zoom factor, keeping centered'''
state = self.state
if self.mouse_pos:
(x, y) = (self.mouse_pos.x, self.mouse_pos.y)
else:
(x, y) = (state.width / 2, state.height / 2)
(lat, lon) = self.coordinates(x, y)
lat = mp_util.constrain(lat, -85, 85)
lon = mp_util.constrain(lon, -180, 180)
state.ground_width *= zoom
# limit ground_width to sane values
state.ground_width = max(state.ground_width, 2)
state.ground_width = min(state.ground_width, 20000000)
self.re_center(x, y, lat, lon)
def draw(self, img, pixmapper, bounds):
'''draw a polygon on the image'''
if self.hidden:
return
(lat,lon,w,h) = bounds
# note that w and h are in degrees
spacing = 1000
while True:
start = mp_util.latlon_round((lat,lon), spacing)
lat2 = mp_util.constrain(lat+h*0.5,-85,85)
lon2 = mp_util.wrap_180(lon+w)
dist = mp_util.gps_distance(lat2,lon,lat2,lon2)
count = int(dist / spacing)
if count < 2:
spacing /= 10
elif count > 50:
spacing *= 10
else:
break
count += 10
for i in range(count):
# draw vertical lines of constant longitude
pos1 = mp_util.gps_newpos(start[0], start[1], 90, i*spacing)
pos3 = (pos1[0]+h*2, pos1[1])
self.draw_line(img, pixmapper, pos1, pos3, self.colour, self.linewidth)
# draw horizontal lines of constant latitude
pos1 = mp_util.gps_newpos(start[0], start[1], 0, i*spacing)
pos3 = (pos1[0], pos1[1]+w*2)
self.draw_line(img, pixmapper, pos1, pos3, self.colour, self.linewidth)
def coord_to_tile(self, lat, lon, zoom):
'''convert lat/lon/zoom to a TileInfo'''
world_tiles = 1<<zoom
lon = mp_util.wrap_180(lon)
x = world_tiles / 360.0 * (lon + 180.0)
tiles_pre_radian = world_tiles / (2 * pi)
e = sin(radians(lat))
e = mp_util.constrain(e, -1+1.0e-15, 1-1.0e-15)
y = world_tiles/2 + 0.5*log((1+e)/(1-e)) * (-tiles_pre_radian)
offsetx = int((x - int(x)) * TILES_WIDTH)
offsety = int((y - int(y)) * TILES_HEIGHT)
return TileInfo((int(x) % world_tiles, int(y) % world_tiles), zoom, self.service, offset=(offsetx, offsety))
def coord_from_area(self, x, y, lat, lon, width, ground_width):
'''return (lat,lon) for a pixel in an area image
x is pixel coord to the right from top,left
y is pixel coord down from top left
'''
scale1 = mp_util.constrain(cos(radians(lat)), 1.0e-15, 1)
pixel_width = ground_width / float(width)
pixel_width_equator = (ground_width / float(width)) / cos(radians(lat))
latr = radians(lat)
y0 = abs(1.0/cos(latr) + tan(latr))
lat2 = 2 * atan(y0 * exp(-(y * pixel_width_equator) / mp_util.radius_of_earth)) - pi/2.0
lat2 = degrees(lat2)
dx = pixel_width_equator * cos(radians(lat2)) * x
(lat2,lon2) = mp_util.gps_offset(lat2, lon, dx, 0)
return (lat2,lon2)
def constrain_latlon(self):
self.state.lat = mp_util.constrain(self.state.lat, -85, 85)
self.state.lon = mp_util.wrap_180(self.state.lon)