initial commit and version 1.0

moviepy/Effect.py

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+"""Defines the base class for all effects in MoviePy."""
+
+import copy as _copy
+from abc import ABCMeta, abstractmethod
+
+from moviepy.Clip import Clip
+
+
+class Effect(metaclass=ABCMeta):
+    """Base abstract class for all effects in MoviePy.
+    Any new effect have to extend this base class.
+    """
+
+    def copy(self):
+        """Return a shallow copy of an Effect.
+
+        You must *always* copy an ``Effect`` before applying,
+        because some of them will modify their own attributes when applied.
+        For example, setting a previously unset property by using target clip property.
+
+        If we was to use the original effect, calling the same effect multiple times
+        could lead to different properties, and different results for equivalent clips.
+
+        By using copy, we ensure we can use the same effect object multiple times while
+        maintaining the same behavior/result.
+
+        In a way, copy makes the effect himself being kind of idempotent.
+        """
+        return _copy.copy(self)
+
+    @abstractmethod
+    def apply(self, clip: Clip) -> Clip:
+        """Apply the current effect on a clip
+
+        Parameters
+        ----------
+        clip
+            The target clip to apply the effect on.
+            (Internally, MoviePy will always pass a copy of the original clip)
+
+        """
+        pass