Fix shift

pygal/line.py

@@ -47,7 +47,7 @@ class Line(BaseGraph):
         self.validate()
         x_step = len(self.series[0].values)
         x_pos = [x / float(x_step - 1) for x in range(x_step)
-        ] if x_step != 1 else [0]  # Center if only one value
+        ] if x_step != 1 else [.5]  # Center if only one value
         vals = [val for serie in self.series for val in serie.values]
         margin = Margin(*(4 * [10]))
         ymin, ymax = min(vals), max(vals)

pygal/view.py

@@ -14,8 +14,6 @@ class View(object):
         self.height = height
         xrng = (xmax - xmin) or 1
         yrng = (ymax - ymin) or 1
-        if xrng == 1:
-            xmin -= .5
         if yrng == 1:
             ymin -= .5
         self.box = Box(xmin, ymin, xrng, yrng)