Merge pull request #282 from WarrenWeckesser/bug-label-arrow-not-visible

BUG: Fix undefined variable in DataLabel when arrow_visible is False.

chaco/data_label.py

@@ -405,8 +405,8 @@ def _render_bubble(self, component, gc, view_bounds=None, mode='normal'):
                     by = y2
                 else:
                     by = y
+            arrow_len = sqrt((px - bx)**2 + (py - by)**2)
 
-        arrow_len = sqrt((px - bx) ** 2 + (py - by) ** 2)
         arrow_visible = (self.arrow_visible and
                          (arrow_len >= self.arrow_min_length))
 

chaco/tests/test_data_label.py

@@ -0,0 +1,30 @@
+import unittest
+from chaco.api import create_scatter_plot, PlotGraphicsContext, DataLabel
+
+
+class DataLabelTestCase(unittest.TestCase):
+
+    def test_data_label_arrow_not_visible(self):
+        # Regression test for https://github.com/enthought/chaco/issues/281
+        # Before the problem was fixed, this test (specifically, using
+        # arrow_visible=False in the DataLabel constructor) would raise an
+        # exception because of an undefined reference.
+        size = (50, 50)
+        plot = create_scatter_plot(data=[range(10), range(10)])
+        label = DataLabel(component=plot,
+                          data_point=(4, 4),
+                          marker_color="red",
+                          marker_size=3,
+                          label_position=(20, 50),
+                          label_style='bubble',
+                          label_text="Something interesting",
+                          label_format="at x=%(x).2f, y=%(y).2f",
+                          arrow_visible=False)
+        plot.overlays.append(label)
+        plot.outer_bounds = list(size)
+        gc = PlotGraphicsContext(size)
+        gc.render_component(plot)
+
+
+if __name__ == "__main__":
+    unittest.main()