Merge 0d3df5f into e76fa0f

enthought · Jul 17, 2014 · 84ca45c · 84ca45c
2 parents e76fa0f + 0d3df5f
commit 84ca45c
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Showing 2 changed files with 74 additions and 15 deletions.
diff --git a/mayavi/filters/threshold.py b/mayavi/filters/threshold.py
@@ -178,22 +178,47 @@ def _update_ranges(self):
         """Updates the ranges of the input.
         """
         data_range = self._get_data_range()
-        if len(data_range) > 0:
-            dr = data_range
-            if self._first:
-                self._data_min, self._data_max = dr
-                self.set(lower_threshold = dr[0], trait_change_notify=False)
+        if len(data_range) == 0:
+            return
+
+        dr = data_range
+        if self._first:
+            self._data_min, self._data_max = dr
+            self.set(lower_threshold = dr[0], trait_change_notify=False)
+            self.upper_threshold = dr[1]
+            self._first = False
+            return
+
+        # Decide whether to change 'lower' or 'upper' first, to avoid
+        # ending up with inconsistent bounds (max < min) in the lower_threshold
+        # and upper_threshold Range traits.
+        if dr[0] <= self._data_min:
+            # Safe to change lower bound first: intermediate range is [dr[0],
+            # self._data_max], and dr[0] <= self._data_min <= self._data_max.
+            change_lower_first = True
+        else:
+            # Safe to change upper bound first: intermediate range is [self._data_min, dr[1]],
+            # and self._data_min < dr[0] <= dr[1].
+            change_lower_first = False
+
+        if change_lower_first:
+            if self.auto_reset_lower:
+                self._data_min = dr[0]
+                notify = not self.auto_reset_upper
+                self.set(lower_threshold = dr[0],
+                         trait_change_notify=notify)
+            if self.auto_reset_upper:
+                self._data_max = dr[1]
                 self.upper_threshold = dr[1]
-                self._first = False
-            else:
-                if self.auto_reset_lower:
-                    self._data_min = dr[0]
-                    notify = not self.auto_reset_upper
-                    self.set(lower_threshold = dr[0],
-                             trait_change_notify=notify)
-                if self.auto_reset_upper:
-                    self._data_max = dr[1]
-                    self.upper_threshold = dr[1]
+        else:
+            if self.auto_reset_upper:
+                self._data_max = dr[1]
+                notify = not self.auto_reset_lower
+                self.set(upper_threshold = dr[1],
+                         trait_change_notify=notify)
+            if self.auto_reset_lower:
+                self._data_min = dr[0]
+                self.lower_threshold = dr[0]
 
     def _get_data_range(self):
         """Returns the range of the input scalar data."""

diff --git a/mayavi/tests/test_threshold_filter.py b/mayavi/tests/test_threshold_filter.py
@@ -72,6 +72,40 @@ def test_threshold_filter_threhsold(self):
                          ))
         return
 
+    def test_threshold_filter_data_range_changes(self):
+        # Regression test for GitHub issue #136.
+        src = self.make_src()
+        self.e.add_source(src)
+        threshold = Threshold()
+        self.e.add_filter(threshold)
+
+        # Move from one data range to another non-overlapping range,
+        # first downwards, then back up.
+        src.scalar_data = np.linspace(3.0, 5.0, 27).reshape((3, 3, 3))
+        self.assertAlmostEqual(threshold.lower_threshold, 3.0)
+        self.assertAlmostEqual(threshold.upper_threshold, 5.0)
+        src.scalar_data = np.linspace(-5.0, -3.0, 27).reshape((3, 3, 3))
+        self.assertAlmostEqual(threshold.lower_threshold, -5.0)
+        self.assertAlmostEqual(threshold.upper_threshold, -3.0)
+        src.scalar_data = np.linspace(3.0, 5.0, 27).reshape((3, 3, 3))
+        self.assertAlmostEqual(threshold.lower_threshold, 3.0)
+        self.assertAlmostEqual(threshold.upper_threshold, 5.0)
+
+        # Narrow and widen.
+        src.scalar_data = np.linspace(4.2, 4.6, 27).reshape((3, 3, 3))
+        self.assertAlmostEqual(threshold.lower_threshold, 4.2)
+        self.assertAlmostEqual(threshold.upper_threshold, 4.6)
+        src.scalar_data = np.linspace(-20.0, 20.0, 27).reshape((3, 3, 3))
+        self.assertAlmostEqual(threshold.lower_threshold, -20.0)
+        self.assertAlmostEqual(threshold.upper_threshold, 20.0)
+
+        # Shift to a range overlapping the previous one.
+        src.scalar_data = np.linspace(-10.0, -30.0, 27).reshape((3, 3, 3))
+        self.assertAlmostEqual(threshold.lower_threshold, -30.0)
+        self.assertAlmostEqual(threshold.upper_threshold, -10.0)
+        src.scalar_data = np.linspace(-20.0, 20.0, 27).reshape((3, 3, 3))
+        self.assertAlmostEqual(threshold.lower_threshold, -20.0)
+        self.assertAlmostEqual(threshold.upper_threshold, 20.0)
 
 
 if __name__ == '__main__':