move FixNullElevation to separate file

2 files changed, 107 insertions, 94 deletions

diff --git a/fietsboek/transformers/__init__.py b/fietsboek/transformers/__init__.py
index 330e699..7df700c 100644
--- a/fietsboek/transformers/__init__.py
+++ b/fietsboek/transformers/__init__.py
@@ -11,7 +11,6 @@ function to load and apply transformers.
 
 from abc import ABC, abstractmethod
 from collections.abc import Callable, Iterable, Mapping
-from itertools import islice
 from typing import Literal, NamedTuple, TypeVar
 
 from gpxpy.gpx import GPX, GPXTrackPoint
@@ -128,99 +127,6 @@ class Transformer(ABC):
         """
 
 
-class FixNullElevation(Transformer):
-    """A transformer that fixes points with zero elevation."""
-
-    @classmethod
-    def identifier(cls) -> str:
-        return "fix-null-elevation"
-
-    @classmethod
-    def name(cls) -> TranslationString:
-        return _("transformers.fix-null-elevation.title")
-
-    @classmethod
-    def description(cls) -> TranslationString:
-        return _("transformers.fix-null-elevation.description")
-
-    @classmethod
-    def parameter_model(cls) -> type[Parameters]:
-        return Parameters
-
-    @property
-    def parameters(self) -> Parameters:
-        return Parameters()
-
-    @parameters.setter
-    def parameters(self, value):
-        pass
-
-    def execute(self, gpx: GPX):
-        def all_points():
-            return gpx.walk(only_points=True)
-
-        def rev_points():
-            # We cannot use reversed(gpx.walk(...)) since that is not a
-            # generator, so we do it manually.
-            return (
-                point
-                for track in reversed(gpx.tracks)
-                for segment in reversed(track.segments)
-                for point in reversed(segment.points)
-            )
-
-        # First, from the front
-        self.fixup(all_points)
-        # Then, from the back
-        self.fixup(rev_points)
-
-    @classmethod
-    def fixup(cls, points: Callable[[], Iterable[GPXTrackPoint]]):
-        """Fixes the given GPX points.
-
-        This iterates over the points and checks for the first point that has a
-        non-zero elevation, and a slope that doesn't exceed 100%. All previous
-        points will have their elevation adjusted to match this first "good
-        point".
-
-        :param points: A function that generates the iterable of points.
-        """
-        max_slope = 1.0
-
-        bad_until = 0
-        final_elevation = 0.0
-        for i, (point, next_point) in enumerate(zip(points(), islice(points(), 1, None))):
-            if (
-                point.elevation is not None
-                and point.elevation != 0.0
-                and cls.slope(point, next_point) < max_slope
-            ):
-                bad_until = i
-                final_elevation = point.elevation
-                break
-
-        for point in islice(points(), None, bad_until):
-            point.elevation = final_elevation
-
-    @staticmethod
-    def slope(point_a: GPXTrackPoint, point_b: GPXTrackPoint) -> float:
-        """Returns the slope between two GPX points.
-
-        This is defined as delta_h / euclid_distance.
-
-        :param point_a: First point.
-        :param point_b: Second point.
-        :return: The slope, as percentage.
-        """
-        if point_a.elevation is None or point_b.elevation is None:
-            return 0.0
-        delta_h = abs(point_a.elevation - point_b.elevation)
-        dist = point_a.distance_2d(point_b)
-        if dist == 0.0 or dist is None:
-            return 0.0
-        return delta_h / dist
-
-
 def list_transformers() -> list[type[Transformer]]:
     """Returns a list of all available transformers.
 
@@ -228,6 +134,7 @@ def list_transformers() -> list[type[Transformer]]:
     """
     # pylint: disable=import-outside-toplevel,cyclic-import
     from .breaks import RemoveBreaks
+    from .elevation import FixNullElevation
 
     return [
         FixNullElevation,
diff --git a/fietsboek/transformers/elevation.py b/fietsboek/transformers/elevation.py
new file mode 100644
index 0000000..0e6f3b0
--- /dev/null
+++ b/fietsboek/transformers/elevation.py
@@ -0,0 +1,106 @@
+"""Transformers that deal with elevation changes in the track."""
+from collections.abc import Callable, Iterable
+from itertools import islice
+
+from gpxpy.gpx import GPX, GPXTrackPoint
+from pyramid.i18n import TranslationString
+
+from . import Parameters, Transformer
+
+_ = TranslationString
+
+
+class FixNullElevation(Transformer):
+    """A transformer that fixes points with zero elevation."""
+
+    @classmethod
+    def identifier(cls) -> str:
+        return "fix-null-elevation"
+
+    @classmethod
+    def name(cls) -> TranslationString:
+        return _("transformers.fix-null-elevation.title")
+
+    @classmethod
+    def description(cls) -> TranslationString:
+        return _("transformers.fix-null-elevation.description")
+
+    @classmethod
+    def parameter_model(cls) -> type[Parameters]:
+        return Parameters
+
+    @property
+    def parameters(self) -> Parameters:
+        return Parameters()
+
+    @parameters.setter
+    def parameters(self, value):
+        pass
+
+    def execute(self, gpx: GPX):
+        def all_points():
+            return gpx.walk(only_points=True)
+
+        def rev_points():
+            # We cannot use reversed(gpx.walk(...)) since that is not a
+            # generator, so we do it manually.
+            return (
+                point
+                for track in reversed(gpx.tracks)
+                for segment in reversed(track.segments)
+                for point in reversed(segment.points)
+            )
+
+        # First, from the front
+        self.fixup(all_points)
+        # Then, from the back
+        self.fixup(rev_points)
+
+    @classmethod
+    def fixup(cls, points: Callable[[], Iterable[GPXTrackPoint]]):
+        """Fixes the given GPX points.
+
+        This iterates over the points and checks for the first point that has a
+        non-zero elevation, and a slope that doesn't exceed 100%. All previous
+        points will have their elevation adjusted to match this first "good
+        point".
+
+        :param points: A function that generates the iterable of points.
+        """
+        max_slope = 1.0
+
+        bad_until = 0
+        final_elevation = 0.0
+        for i, (point, next_point) in enumerate(zip(points(), islice(points(), 1, None))):
+            if (
+                point.elevation is not None
+                and point.elevation != 0.0
+                and cls.slope(point, next_point) < max_slope
+            ):
+                bad_until = i
+                final_elevation = point.elevation
+                break
+
+        for point in islice(points(), None, bad_until):
+            point.elevation = final_elevation
+
+    @staticmethod
+    def slope(point_a: GPXTrackPoint, point_b: GPXTrackPoint) -> float:
+        """Returns the slope between two GPX points.
+
+        This is defined as delta_h / euclid_distance.
+
+        :param point_a: First point.
+        :param point_b: Second point.
+        :return: The slope, as percentage.
+        """
+        if point_a.elevation is None or point_b.elevation is None:
+            return 0.0
+        delta_h = abs(point_a.elevation - point_b.elevation)
+        dist = point_a.distance_2d(point_b)
+        if dist == 0.0 or dist is None:
+            return 0.0
+        return delta_h / dist
+
+
+__all__ = ["FixNullElevation"]