BUG: Fix Skew tick implementation.

dopplershift · dopplershift · commit 73ee9f26073a · 2016-11-18T12:29:01.000-07:00
Previous fixes broke upper ticks so that they never showed up. This
comes from checking the default position, 0, against the upper range.
Instead, use a sentinel of None for the default position. If a tick has
the default position, avoid checking against the interval.
diff --git a/examples/api/skewt.py b/examples/api/skewt.py
@@ -24,19 +24,30 @@
 # The sole purpose of this class is to look at the upper, lower, or total
 # interval as appropriate and see what parts of the tick to draw, if any.
 class SkewXTick(maxis.XTick):
+    def update_position(self, loc):
+        # This ensures that the new value of the location is set before
+        # any other updates take place
+        self._loc = loc
+        super(SkewXTick, self).update_position(loc)
+
+    def _has_default_loc(self):
+        return self.get_loc() is None
+
     def _need_lower(self):
-        return transforms.interval_contains(self.axes.lower_xlim,
-                                            self.get_loc())
+        return (self._has_default_loc() or
+                transforms.interval_contains(self.axes.lower_xlim,
+                                             self.get_loc()))
 
     def _need_upper(self):
-        return transforms.interval_contains(self.axes.upper_xlim,
-                                            self.get_loc())
+        return (self._has_default_loc() or
+                transforms.interval_contains(self.axes.upper_xlim,
+                                             self.get_loc()))
 
     @property
     def gridOn(self):
-        return (self._gridOn and
+        return (self._gridOn and (self._has_default_loc() or
                 transforms.interval_contains(self.get_view_interval(),
-                                             self.get_loc()))
+                                             self.get_loc())))
 
     @gridOn.setter
     def gridOn(self, value):
@@ -82,7 +93,7 @@ def get_view_interval(self):
 # as well as create instances of the custom tick
 class SkewXAxis(maxis.XAxis):
     def _get_tick(self, major):
-        return SkewXTick(self.axes, 0, '', major=major)
+        return SkewXTick(self.axes, None, '', major=major)
 
     def get_view_interval(self):
         return self.axes.upper_xlim[0], self.axes.lower_xlim[1]
diff --git a/lib/matplotlib/tests/test_skew.py b/lib/matplotlib/tests/test_skew.py
@@ -20,19 +20,30 @@
 # The sole purpose of this class is to look at the upper, lower, or total
 # interval as appropriate and see what parts of the tick to draw, if any.
 class SkewXTick(maxis.XTick):
+    def update_position(self, loc):
+        # This ensures that the new value of the location is set before
+        # any other updates take place
+        self._loc = loc
+        super(SkewXTick, self).update_position(loc)
+
+    def _has_default_loc(self):
+        return self.get_loc() is None
+
     def _need_lower(self):
-        return transforms.interval_contains(self.axes.lower_xlim,
-                                            self.get_loc())
+        return (self._has_default_loc() or
+                transforms.interval_contains(self.axes.lower_xlim,
+                                             self.get_loc()))
 
     def _need_upper(self):
-        return transforms.interval_contains(self.axes.upper_xlim,
-                                            self.get_loc())
+        return (self._has_default_loc() or
+                transforms.interval_contains(self.axes.upper_xlim,
+                                             self.get_loc()))
 
     @property
     def gridOn(self):
-        return (self._gridOn and
+        return (self._gridOn and (self._has_default_loc() or
                 transforms.interval_contains(self.get_view_interval(),
-                                             self.get_loc()))
+                                             self.get_loc())))
 
     @gridOn.setter
     def gridOn(self, value):
@@ -78,7 +89,7 @@ def get_view_interval(self):
 # as well as create instances of the custom tick
 class SkewXAxis(maxis.XAxis):
     def _get_tick(self, major):
-        return SkewXTick(self.axes, 0, '', major=major)
+        return SkewXTick(self.axes, None, '', major=major)
 
     def get_view_interval(self):
         return self.axes.upper_xlim[0], self.axes.lower_xlim[1]
