Only evaluate necessary transforms.

Dict evaulation is not lazy: previously, this code evaluated all allowable transforms before picking the appropriate one. This is now fixed by breaking it down into the rotation transfrom, then passing the result to one function from a dict of flip transform functions.

Author: mickp

microscope/devices.py

@@ -698,11 +698,14 @@ def _process_data(self, data):
         rot = self._transform[2]
 
         # Choose appropriate transform based on (flips, rot).
-        data = {(0, 0): numpy.rot90(data, rot),
-               (0, 1): numpy.flipud(numpy.rot90(data, rot)),
-               (1, 0): numpy.fliplr(numpy.rot90(data, rot)),
-               (1, 1): numpy.fliplr(numpy.flipud(numpy.rot90(data, rot)))
-               }[flips]
+        # Do rotation
+        data = numpy.rot90(data, rot)
+        # Flip
+        data = {(0, 0): lambda d: d,
+               (0, 1): numpy.flipud,
+               (1, 0): numpy.fliplr,
+               (1, 1): lambda d: numpy.fliplr(numpy.flipud(d))
+               }[flips](data)
         return super()._process_data(data)
 
     def set_readout_mode(self, description):