simple filters...

api_test.py

@@ -117,10 +117,14 @@ for t in tests:
     assert(sd.ndim == dd.ndim)
     assert(np.array_equal(sd.load(), dd))
 
-# test put method
+# test put method & simple filters
 
-stream = Stream('test')
-outlet = stream.filter()
+def test(data):
+    assert(np.array_equal(data, data_a[0]))
+
+stream0 = Stream('test')
+stream1 = stream0.filter(process_frame = lambda data: data)
+stream2 = stream1.filter(process_frame = test)
 stream.put(data_a[0])
 
 

bob/io/stream/stream.py

@@ -223,19 +223,22 @@ def stream_filter(name):
 ################################################################################
 # Stream Filters
 
-### Filter general class ###
+### Filter general class & simple filter ###
 @stream_filter('filter')
 class StreamFilter(Stream):
-    def __init__(self, name, parent):
+    def __init__(self, name, parent, process_frame=None):
+        self.__process_frame = process_frame
         super().__init__(name=name, parent=parent)
-        pass
 
     def process(self, data, indices):
         assert isinstance(indices, list)
         return np.stack([self.process_frame(data[i], i, indices[i]) for i in range(data.shape[0])])
 
     def process_frame(self, data, data_index, stream_index):
-        return data
+        if self.__process_frame is not None:
+            return self.__process_frame(data)
+        else:
+            return data
 
     # load one or several frames
     def load(self, index=None):