Commit b25d759b authored by Justin Bronn's avatar Justin Bronn
Browse files

Fixed #8113. Made `get_width_height` a `GoogleZoom` method that takes the... 

Fixed #8113.  Made `get_width_height` a `GoogleZoom` method that takes the extent instead of an envelope so it may handle Point geometries.  Thanks to Santiago Aguiar for the bug report.


git-svn-id: http://code.djangoproject.com/svn/django/trunk@8428 bcc190cf-cafb-0310-a4f2-bffc1f526a37
parent e3ea9dde

django/contrib/gis/maps/google/zoom.py

+34 −37
Original line number Diff line number Diff line
@@ -6,17 +6,6 @@ from math import pi, sin, cos, log, exp, atan 
DTOR = pi / 180.

RTOD = 180. / pi



def get_width_height(envelope):

    # Getting the lower-left, upper-left, and upper-right

    #  coordinates of the envelope.

    ll = Point(envelope[0][0])

    ul = Point(envelope[0][1])

    ur = Point(envelope[0][2])

    

    height = ll.distance(ul)

    width  = ul.distance(ur)

    return width, height



class GoogleZoom(object):

    """

    GoogleZoom is a utility for performing operations related to the zoom
@@ -34,21 +23,19 @@ class GoogleZoom(object): 
    

    def __init__(self, num_zoom=19, tilesize=256):

        "Initializes the Google Zoom object."



        # Google's tilesize is 256x256, square tiles are assumed.

        self._tilesize = tilesize

        

        # The number of zoom levels

        self._nzoom = num_zoom



        # Initializing arrays to hold the parameters for each

        #  one of the zoom levels.

        # Initializing arrays to hold the parameters for each one of the 

        # zoom levels.

        self._degpp = [] # Degrees per pixel

        self._radpp = [] # Radians per pixel

        self._npix  = [] # 1/2 the number of pixels for a tile at the given zoom level

        

        # Incrementing through the zoom levels and populating the

        #  parameter arrays.

        # Incrementing through the zoom levels and populating the parameter arrays.

        z = tilesize # The number of pixels per zoom level.

        for i in xrange(num_zoom):

            # Getting the degrees and radians per pixel, and the 1/2 the number of
@@ -79,9 +66,8 @@ class GoogleZoom(object): 
        lon, lat = self.get_lon_lat(lonlat)

        npix = self._npix[zoom]



        # Calculating the pixel x coordinate by multiplying the longitude

        #  value with with the number of degrees/pixel at the given

        #  zoom level.

        # Calculating the pixel x coordinate by multiplying the longitude value

        # with with the number of degrees/pixel at the given zoom level.

        px_x = round(npix + (lon * self._degpp[zoom]))



        # Creating the factor, and ensuring that 1 or -1 is not passed in as the
@@ -136,7 +122,6 @@ class GoogleZoom(object): 
        

    def get_zoom(self, geom):

        "Returns the optimal Zoom level for the given geometry."



        # Checking the input type.

        if not isinstance(geom, GEOSGeometry) or geom.srid != 4326:

            raise TypeError('get_zoom() expects a GEOS Geometry with an SRID of 4326.')
@@ -144,13 +129,12 @@ class GoogleZoom(object): 
        # Getting the envelope for the geometry, and its associated width, height

        # and centroid.

        env = geom.envelope

        env_w, env_h = get_width_height(env)

        env_w, env_h = self.get_width_height(env.extent)

        center = env.centroid



        for z in xrange(self._nzoom):

            # Getting the tile at the zoom level.

            tile = self.tile(center, z)

            tile_w, tile_h = get_width_height(tile)

            tile_w, tile_h = self.get_width_height(self.tile(center, z).extent)



            # When we span more than one tile, this is an approximately good

            # zoom level.
@@ -162,3 +146,16 @@ class GoogleZoom(object): 
        # Otherwise, we've zoomed in to the max.

        return self._nzoom-1



    def get_width_height(self, extent):

        """

        Returns the width and height for the given extent.

        """

        # Getting the lower-left, upper-left, and upper-right

        # coordinates from the extent.

        ll = Point(extent[:2])

        ul = Point(extent[0], extent[3])

        ur = Point(extent[2:])

        # Calculating the width and height.

        height = ll.distance(ul)

        width  = ul.distance(ur)

        return width, height