Issue #39: support flipping icons horizontally.

If tags has "direction" key, direction is mostly to the left (to the
West), and shape for the icon is right directed, we flip the shape
horizontally.

roentgen/icon.py

@@ -39,6 +39,7 @@ class Shape:
     offset: np.array  # vector that should be used to shift the path
     id_: str  # shape identifier
     name: Optional[str] = None  # icon description
+    is_right_directed: bool = False
 
     def is_default(self) -> bool:
         """
@@ -98,6 +99,7 @@ class ShapeExtractor:
         :param svg_file_name: input SVG file name with icons.  File may contain
             any other irrelevant graphics.
         """
+        self.configuration = ShapeConfiguration(configuration_file_name)
         self.shapes: Dict[str, Shape] = {}
 
         with open(svg_file_name) as input_file:
@@ -109,8 +111,6 @@ class ShapeExtractor:
                     if isinstance(node, Element):
                         self.parse(node)
 
-        self.configuration = ShapeConfiguration(configuration_file_name)
-
     def parse(self, node: Element) -> None:
         """
         Extract icon paths into a map.
@@ -154,7 +154,10 @@ class ShapeExtractor:
                     name = child_node.childNodes[0].nodeValue
                     break
 
-            self.shapes[id_] = Shape(path, point, id_, name)
+            is_right_directed: bool = (
+                id_ in self.configuration.right_directed
+            )
+            self.shapes[id_] = Shape(path, point, id_, name, is_right_directed)
         else:
             error(f"not standard ID {id_}")
 

roentgen/scheme.py

@@ -10,6 +10,7 @@ from typing import Any, Dict, List, Optional, Set, Tuple, Union
 import yaml
 from colour import Color
 
+from roentgen.direction import DirectionSet
 from roentgen.icon import (
     DEFAULT_COLOR, DEFAULT_SHAPE_ID, Icon, IconSet, ShapeExtractor,
     ShapeSpecification
@@ -184,6 +185,7 @@ class Scheme:
         :param icon_extractor: extractor with icon specifications
         :param tags: OpenStreetMap element tags dictionary
         :param for_: target (node, way, area or relation)
+        :return (icon set, icon priority)
         """
         tags_hash: str = (
             ",".join(tags.keys()) + ":" + ",".join(map(str, tags.values()))
@@ -191,7 +193,7 @@ class Scheme:
         if tags_hash in self.cache:
             return self.cache[tags_hash]
 
-        main_icon: Icon = None
+        main_icon: Optional[Icon] = None
         extra_icons: List[Icon] = []
         processed: Set[str] = set()
         priority: int = 0
@@ -264,6 +266,12 @@ class Scheme:
         returned: IconSet = IconSet(main_icon, extra_icons, processed)
         self.cache[tags_hash] = returned, priority
 
+        if "direction" in tags:
+            if DirectionSet(tags["direction"]).is_right() is False:
+                for specification in main_icon.shape_specifications:
+                    if specification.shape.is_right_directed:
+                        specification.flip_horizontally = True
+
         return returned, priority
 
     def get_style(self, tags: Dict[str, Any], scale):