Add pyproj and methods to set center and zoom

Author: stfnkth

docs/examples/concepts/basic_map.py

@@ -7,5 +7,6 @@
 m.add_control(ol.FullScreenControl())
 
 # m.add_view_call("setZoom", 5)
-m.set_zoom(5)
+m.set_zoom(12)
+m.set_center(lonlat=(-122.4, 37.74))
 m.save()

pyproject.toml

@@ -10,6 +10,7 @@ dependencies = [
     "eval-type-backport>=0.2.2",
     "jinja2>=3.1.6",
     "pydantic>=2.5.3",
+    "pyproj>=3.6.1",
 ]
 
 # [project.scripts]

src/openlayers/map.py

@@ -64,6 +64,12 @@ def set_zoom(self, zoom_level: float | int) -> None:
             zoom_level (float | int): The zoom level of the view
         """
         self.add_view_call("setZoom", zoom_level)
+
+    def set_center(self, lonlat: tuple[float, float] = None, center: tuple[float, float] = None) -> None:
+        from .utils import default_crs_transformer
+
+        center = center or default_crs_transformer().transform(*lonlat)
+        self.add_view_call("setCenter", center)
 
     def add_layer(self, layer: LayerT | LayerLike | dict) -> None:
         """Add a layer to the map

src/openlayers/utils.py

@@ -2,11 +2,16 @@
 
 import base64
 from pathlib import Path
-
+from pyproj import Transformer, CRS
 
 def create_icon_src_from_file(filename: str) -> bytes:
     with open(filename, "rb") as f:
         encoded_image = base64.b64encode(f.read()).decode("utf-8")
 
     image_type = Path(filename).suffix.replace(".", "")
     return f"data:image/{image_type};base64," + encoded_image
+
+def default_crs_transformer() -> Transformer:
+    crs_from = CRS.from_epsg(4326)
+    crs_to = CRS.from_epsg(3857)
+    return Transformer.from_crs(crs_from=crs_from, crs_to=crs_to, always_xy=True)

tests/test_utils.py

@@ -0,0 +1,11 @@
+from openlayers.utils import default_crs_transformer
+
+def test_crs_transformer() -> None:
+    lon = -122.4
+    lat = 37.74
+    
+    transformer = default_crs_transformer()
+    center = (lon, lat)
+    coords = transformer.transform(*center)
+
+    print(coords)