def test_width_and_height(self):
ts = TileGrid(4, 2, 1, 540, 540, GLOBAL_GEO_EXTENT, inv_y=False)
self.assertEqual(ts.width(2), 4320)
self.assertEqual(ts.height(2), 2160)
self.assertEqual(ts.max_width, 8640)
self.assertEqual(ts.max_height, 4320)
self.assertEqual(ts.min_width, 1080)
self.assertEqual(ts.min_height, 540)
def _tile_grid_to_ol4x_xyz_source_options(tile_grid: TileGrid, url: str):
"""
Convert TileGrid into options to be used with ol.source.XYZ(options) of OpenLayers 4.x.
See
* https://openlayers.org/en/latest/apidoc/ol.source.XYZ.html
* https://openlayers.org/en/latest/examples/xyz.html
:param tile_grid: tile grid
:param url: source url
:return:
"""
west, south, east, north = tile_grid.geo_extent
delta_x = east - west + (0 if east >= west else 360)
delta_y = north - south
width = tile_grid.width(0)
height = tile_grid.height(0)
res0_x = delta_x / width
res0_y = delta_y / height
res0 = max(res0_x, res0_y)
if abs(res0_y - res0_x) >= 1.e-5:
warnings.warn(
f'spatial resolutions in x and y direction differ significantly:'
f' {res0_x} and {res0_y} degrees, using maximum {res0}')
# https://openlayers.org/en/latest/examples/xyz.html
# https://openlayers.org/en/latest/apidoc/ol.source.XYZ.html
return dict(
url=url,
projection='EPSG:4326',
minZoom=0,
maxZoom=tile_grid.num_levels - 1,
tileGrid=dict(
extent=[west, south, east, north],
origin=[west, south if tile_grid.inv_y else north],
tileSize=[tile_grid.tile_size[0], tile_grid.tile_size[1]],
resolutions=[res0 / (2**i) for i in range(tile_grid.num_levels)]))
