Merge pull request #6192 from jenshnielsen/tighter-axes-limits

More precise choice of axes limits.

lib/matplotlib/tests/test_axes.py

@@ -24,7 +24,7 @@
 from matplotlib.testing.decorators import image_comparison, cleanup
 import matplotlib.pyplot as plt
 import matplotlib.markers as mmarkers
-from numpy.testing import assert_array_equal
+from numpy.testing import assert_allclose, assert_array_equal
 import warnings
 from matplotlib.cbook import IgnoredKeywordWarning
 
@@ -3725,8 +3725,7 @@ def test_vline_limit():
     ax.axvline(0.5)
     ax.plot([-0.1, 0, 0.2, 0.1])
     (ymin, ymax) = ax.get_ylim()
-    assert ymin == -0.1
-    assert ymax == 0.25
+    assert_allclose(ax.get_ylim(), (-.1, .2))
 
 
 @cleanup

lib/matplotlib/ticker.py

@@ -161,13 +161,23 @@
 from matplotlib import rcParams
 from matplotlib import cbook
 from matplotlib import transforms as mtransforms
+from matplotlib.cbook import mplDeprecation
 
 import warnings
 
 if six.PY3:
     long = int
 
 
+# Work around numpy/numpy#6127.
+def _divmod(x, y):
+    if isinstance(x, np.generic):
+        x = x.item()
+    if isinstance(y, np.generic):
+        y = y.item()
+    return six.moves.builtins.divmod(x, y)
+
+
 def _mathdefault(s):
     """
     For backward compatibility, in classic mode we display
@@ -1221,7 +1231,7 @@ def view_limits(self, vmin, vmax):
             vmax += 1
 
         if rcParams['axes.autolimit_mode'] == 'round_numbers':
-            exponent, remainder = divmod(math.log10(vmax - vmin), 1)
+            exponent, remainder = _divmod(math.log10(vmax - vmin), 1)
             if remainder < 0.5:
                 exponent -= 1
             scale = 10 ** (-exponent)
@@ -1247,30 +1257,30 @@ def __init__(self, base):
 
     def lt(self, x):
         'return the largest multiple of base < x'
-        d, m = divmod(x, self._base)
+        d, m = _divmod(x, self._base)
         if closeto(m, 0) and not closeto(m / self._base, 1):
             return (d - 1) * self._base
         return d * self._base
 
     def le(self, x):
         'return the largest multiple of base <= x'
-        d, m = divmod(x, self._base)
+        d, m = _divmod(x, self._base)
         if closeto(m / self._base, 1):  # was closeto(m, self._base)
             #looks like floating point error
             return (d + 1) * self._base
         return d * self._base
 
     def gt(self, x):
         'return the smallest multiple of base > x'
-        d, m = divmod(x, self._base)
+        d, m = _divmod(x, self._base)
         if closeto(m / self._base, 1):
             #looks like floating point error
             return (d + 2) * self._base
         return (d + 1) * self._base
 
     def ge(self, x):
         'return the smallest multiple of base >= x'
-        d, m = divmod(x, self._base)
+        d, m = _divmod(x, self._base)
         if closeto(m, 0) and not closeto(m / self._base, 1):
             return d * self._base
         return (d + 1) * self._base
@@ -1326,23 +1336,13 @@ def view_limits(self, dmin, dmax):
 
 
 def scale_range(vmin, vmax, n=1, threshold=100):
-    dv = abs(vmax - vmin)
-    if dv == 0:     # maxabsv == 0 is a special case of this.
-        return 1.0, 0.0
-        # Note: this should never occur because
-        # vmin, vmax should have been checked by nonsingular(),
-        # and spread apart if necessary.
-    meanv = 0.5 * (vmax + vmin)
+    dv = abs(vmax - vmin)  # > 0 as nonsingular is called before.
+    meanv = (vmax + vmin) / 2
     if abs(meanv) / dv < threshold:
         offset = 0
-    elif meanv > 0:
-        ex = divmod(math.log10(meanv), 1)[0]
-        offset = 10 ** ex
     else:
-        ex = divmod(math.log10(-meanv), 1)[0]
-        offset = -10 ** ex
-    ex = divmod(math.log10(dv / n), 1)[0]
-    scale = 10 ** ex
+        offset = math.copysign(10 ** (math.log10(abs(meanv)) // 1), meanv)
+    scale = 10 ** (math.log10(dv / n) // 1)
     return scale, offset
 
 
@@ -1352,7 +1352,6 @@ class MaxNLocator(Locator):
     """
     default_params = dict(nbins=10,
                           steps=None,
-                          trim=True,
                           integer=False,
                           symmetric=False,
                           prune=None)
@@ -1388,9 +1387,6 @@ def __init__(self, *args, **kwargs):
             will be removed.  If prune==None, no ticks will be removed.
 
         """
-        # I left "trim" out; it defaults to True, and it is not
-        # clear that there is any use case for False, so we may
-        # want to remove that kwarg.  EF 2010/04/18
         if args:
             kwargs['nbins'] = args[0]
             if len(args) > 1:
@@ -1406,7 +1402,9 @@ def set_params(self, **kwargs):
             if self._nbins != 'auto':
                 self._nbins = int(self._nbins)
         if 'trim' in kwargs:
-            self._trim = kwargs['trim']
+            warnings.warn(
+                "The 'trim' keyword has no effect since version 2.0.",
+                mplDeprecation)
         if 'integer' in kwargs:
             self._integer = kwargs['integer']
         if 'symmetric' in kwargs:
@@ -1429,9 +1427,9 @@ def set_params(self, **kwargs):
         if 'integer' in kwargs:
             self._integer = kwargs['integer']
         if self._integer:
-            self._steps = [n for n in self._steps if divmod(n, 1)[1] < 0.001]
+            self._steps = [n for n in self._steps if _divmod(n, 1)[1] < 0.001]
 
-    def bin_boundaries(self, vmin, vmax):
+    def _raw_ticks(self, vmin, vmax):
         nbins = self._nbins
         if nbins == 'auto':
             nbins = max(min(self.axis.get_tick_space(), 9), 1)
@@ -1449,23 +1447,30 @@ def bin_boundaries(self, vmin, vmax):
             if step < scaled_raw_step:
                 continue
             step *= scale
-            best_vmin = step * divmod(vmin, step)[0]
+            best_vmin = vmin // step * step
             best_vmax = best_vmin + step * nbins
-            if (best_vmax >= vmax):
+            if best_vmax >= vmax:
                 break
-        if self._trim:
-            extra_bins = int(divmod((best_vmax - vmax), step)[0])
-            nbins -= extra_bins
-        return (np.arange(nbins + 1) * step + best_vmin + offset)
+
+        # More than nbins may be required, e.g. vmin, vmax = -4.1, 4.1 gives
+        # nbins=9 but 10 bins are actually required after rounding.  So we just
+        # create the bins that span the range we need instead.
+        low = round(Base(step).le(vmin - best_vmin) / step)
+        high = round(Base(step).ge(vmax - best_vmin) / step)
+        return np.arange(low, high + 1) * step + best_vmin + offset
+
+    @cbook.deprecated("2.0")
+    def bin_boundaries(self, vmin, vmax):
+        return self._raw_ticks(vmin, vmax)
 
     def __call__(self):
         vmin, vmax = self.axis.get_view_interval()
         return self.tick_values(vmin, vmax)
 
     def tick_values(self, vmin, vmax):
-        vmin, vmax = mtransforms.nonsingular(vmin, vmax, expander=1e-13,
-                                                         tiny=1e-14)
-        locs = self.bin_boundaries(vmin, vmax)
+        vmin, vmax = mtransforms.nonsingular(
+            vmin, vmax, expander=1e-13, tiny=1e-14)
+        locs = self._raw_ticks(vmin, vmax)
         prune = self._prune
         if prune == 'lower':
             locs = locs[1:]
@@ -1482,11 +1487,11 @@ def view_limits(self, dmin, dmax):
                 dmin = -maxabs
                 dmax = maxabs
 
-        dmin, dmax = mtransforms.nonsingular(dmin, dmax, expander=1e-12,
-                                                        tiny=1.e-13)
+        dmin, dmax = mtransforms.nonsingular(
+            dmin, dmax, expander=1e-12, tiny=1e-13)
 
         if rcParams['axes.autolimit_mode'] == 'round_numbers':
-            return np.take(self.bin_boundaries(dmin, dmax), [0, -1])
+            return self._raw_ticks(dmin, dmax)[[0, -1]]
         else:
             return dmin, dmax