ILinePlot: only pass the necessary data when xlim is passed

xlim limits the x axis to a given range, but for ILinePlot we pass all
the data to dygraph and then let dygraph apply the window.  That means
that we include a lot of useless data in the notebook and we lose
performance parsing data that will never be plotted.

Improve xlim for ILinePlot so that it only embeds the data relevant for
the plot.

1 files changed, 25 insertions, 0 deletions

diff --git a/tests/test_constraint.py b/tests/test_constraint.py
index c92d0b3..438fa97 100644
--- a/tests/test_constraint.py
+++ b/tests/test_constraint.py
@@ -159,3 +159,28 @@ class TestConstraintManager(unittest.TestCase):
 
         self.assertEquals(result[0].iloc[0], 3)
         self.assertEquals(result[1].iloc[0], 3)
+
+    def test_constraint_with_window(self):
+        """Test that the constraint manager can constraint to a window of time"""
+        c_mgr = ConstraintManager(self.dfrs[0], "freq", None, AttrConf.PIVOT, {},
+                                  window=(1, 3))
+
+        constraint = iter(c_mgr).next()
+        series = constraint.result[AttrConf.PIVOT_VAL]
+        self.assertEquals(len(series), 3)
+
+        # For the graph to plot a value at 0.75, the resulting series
+        # must contain the value before 0.75.  Same for the upper limit.
+        c_mgr = ConstraintManager(self.dfrs[0], "freq", None, AttrConf.PIVOT, {},
+                                  window=(0.75, 1.5))
+
+        constraint = iter(c_mgr).next()
+        series = constraint.result[AttrConf.PIVOT_VAL]
+        self.assertEquals(series.index.tolist(), [0, 1, 2])
+
+        c_mgr = ConstraintManager(self.dfrs[0], "freq", None, AttrConf.PIVOT, {},
+                                  window=(0, 2))
+
+        constraint = iter(c_mgr).next()
+        series = constraint.result[AttrConf.PIVOT_VAL]
+        self.assertEquals(len(series), 3)