better shadow casting

src/c3nav/mapdata/models/level.py

@@ -1,11 +1,10 @@
 from django.db import models
 from django.utils.functional import cached_property
 from django.utils.translation import ugettext_lazy as _
-from shapely.geometry import CAP_STYLE, JOIN_STYLE
+from shapely.geometry import JOIN_STYLE
 from shapely.ops import cascaded_union
 
 from c3nav.mapdata.models.base import MapItem
-from c3nav.mapdata.utils import assert_multipolygon
 
 
 class Level(MapItem):
@@ -149,15 +148,4 @@ class LevelGeometries():
         return self.get_levelconnectors()
 
     def intermediate_shadows(self, to_level=None):
-        rings = []
-        for polygon in assert_multipolygon(self.buildings):
-            rings.append(polygon.exterior)
-            rings.extend(polygon.interiors)
-
-        objects = []
-        levelconnectors = self.get_levelconnectors(to_level)
-        for ring in rings:
-            objects.append(ring.difference(levelconnectors))
-        lines = cascaded_union(objects)
-
-        return lines.buffer(0.1, cap_style=CAP_STYLE.flat, join_style=JOIN_STYLE.mitre)
+        return self.buildings.difference(self.get_levelconnectors(to_level))

src/c3nav/mapdata/render/renderer.py

@@ -177,7 +177,8 @@ class LevelRenderer():
         contents = self.add_svg_content(svg)
         for level in higher:
             contents.append(self.polygon_svg(level.geometries.intermediate_shadows(to_level=self.level),
-                                             fill_color='#9E9E9E'))
+                                             stroke_color='#9E9E9E',
+                                             stroke_width=0.1))
 
         for level in higher:
             self.add_svg_image(svg, 'file://'+get_render_path('level-%s.base.png' % level.name))