Refactor buildings and craters.

map_machine/feature/crater.py

@@ -0,0 +1,46 @@
+"""
+Crater on the map.
+"""
+import numpy as np
+from colour import Color
+from svgwrite import Drawing
+
+from map_machine.geometry.flinger import Flinger
+from map_machine.osm.osm_reader import Tagged
+
+
+class Crater(Tagged):
+    """Volcano or impact crater on the map."""
+
+    def __init__(
+        self, tags: dict[str, str], coordinates: np.ndarray, point: np.ndarray
+    ) -> None:
+        super().__init__(tags)
+        self.coordinates: np.ndarray = coordinates
+        self.point: np.ndarray = point
+
+    def draw(self, svg: Drawing, flinger: Flinger) -> None:
+        """Draw crater ridge."""
+        scale: float = flinger.get_scale(self.coordinates)
+        assert "diameter" in self.tags
+        radius: float = float(self.tags["diameter"]) / 2.0
+        radial_gradient = svg.radialGradient(
+            center=self.point + np.array((0.0, radius * scale / 7.0)),
+            r=radius * scale,
+            gradientUnits="userSpaceOnUse",
+        )
+        color: Color = Color("#000000")
+        gradient = svg.defs.add(radial_gradient)
+        (
+            gradient
+            .add_stop_color(0.0, color.hex, opacity=0.2)
+            .add_stop_color(0.7, color.hex, opacity=0.2)
+            .add_stop_color(1.0, color.hex, opacity=1.0)
+        )  # fmt: skip
+        circle = svg.circle(
+            self.point,
+            radius * scale,
+            fill=gradient.get_funciri(),
+            opacity=0.2,
+        )
+        svg.add(circle)