BUG: make autoscale('tight') set margins to zero; closes matplotlib#6968

Author: efiring

lib/matplotlib/axes/_base.py

@@ -2185,6 +2185,10 @@ def autoscale(self, enable=True, axis='both', tight=None):
             if axis in ['y', 'both']:
                 self._autoscaleYon = bool(enable)
                 scaley = self._autoscaleYon
+        if tight and scalex:
+            self._xmargin = 0
+        if tight and scaley:
+            self._ymargin = 0
         self.autoscale_view(tight=tight, scalex=scalex, scaley=scaley)
 
     def autoscale_view(self, tight=None, scalex=True, scaley=True):
@@ -2194,6 +2198,14 @@ def autoscale_view(self, tight=None, scalex=True, scaley=True):
         setting *scaley* to *False*.  The autoscaling preserves any
         axis direction reversal that has already been done.
 
+        If *tight* is *False*, the axis major locator will be used
+        to expand the view limits if rcParams['axes.autolimit_mode']
+        is 'round_numbers'.  Note that any margins that are in effect
+        will be applied first, regardless of whether *tight* is
+        *True* or *False*.  Specifying *tight* as *True* or *False*
+        saves the setting as a private attribute of the Axes; specifying
+        it as *None* (the default) applies the previously saved value.
+
         The data limits are not updated automatically when artist data are
         changed after the artist has been added to an Axes instance.  In that
         case, use :meth:`matplotlib.axes.Axes.relim` prior to calling
@@ -2246,52 +2258,56 @@ def autoscale_view(self, tight=None, scalex=True, scaley=True):
         def handle_single_axis(scale, autoscaleon, shared_axes, interval,
                                minpos, axis, margin, do_lower_margin,
                                do_upper_margin, set_bound):
-            if scale and autoscaleon:
-                shared = shared_axes.get_siblings(self)
-                dl = [ax.dataLim for ax in shared]
-                # ignore non-finite data limits if good limits exist
-                finite_dl = [d for d in dl if np.isfinite(d).all()]
-                if len(finite_dl):
-                    dl = finite_dl
-
-                bb = mtransforms.BboxBase.union(dl)
-                x0, x1 = getattr(bb, interval)
-                locator = axis.get_major_locator()
-                try:
-                    # e.g., DateLocator has its own nonsingular()
-                    x0, x1 = locator.nonsingular(x0, x1)
-                except AttributeError:
-                    # Default nonsingular for, e.g., MaxNLocator
-                    x0, x1 = mtransforms.nonsingular(
-                        x0, x1, increasing=False, expander=0.05)
-
-                if margin > 0 and (do_lower_margin or do_upper_margin):
-                    if axis.get_scale() == 'linear':
-                        delta = (x1 - x0) * margin
-                        if do_lower_margin:
-                            x0 -= delta
-                        if do_upper_margin:
-                            x1 += delta
-                    else:
-                        # If we have a non-linear scale, we need to
-                        # add the margin in figure space and then
-                        # transform back
-                        minpos = getattr(bb, minpos)
-                        transform = axis.get_transform()
-                        inverse_trans = transform.inverted()
-                        x0, x1 = axis._scale.limit_range_for_scale(
-                            x0, x1, minpos)
-                        x0t, x1t = transform.transform([x0, x1])
-                        delta = (x1t - x0t) * margin
-                        if do_lower_margin:
-                            x0t -= delta
-                        if do_upper_margin:
-                            x1t += delta
-                        x0, x1 = inverse_trans.transform([x0t, x1t])
-
-                if not _tight:
-                    x0, x1 = locator.view_limits(x0, x1)
-                set_bound(x0, x1)
+
+            if not (scale and autoscaleon):
+                return  # nothing to do...
+
+            shared = shared_axes.get_siblings(self)
+            dl = [ax.dataLim for ax in shared]
+            # ignore non-finite data limits if good limits exist
+            finite_dl = [d for d in dl if np.isfinite(d).all()]
+            if len(finite_dl):
+                dl = finite_dl
+
+            bb = mtransforms.BboxBase.union(dl)
+            x0, x1 = getattr(bb, interval)
+            locator = axis.get_major_locator()
+            try:
+                # e.g., DateLocator has its own nonsingular()
+                x0, x1 = locator.nonsingular(x0, x1)
+            except AttributeError:
+                # Default nonsingular for, e.g., MaxNLocator
+                x0, x1 = mtransforms.nonsingular(
+                    x0, x1, increasing=False, expander=0.05)
+
+            if margin > 0 and (do_lower_margin or do_upper_margin):
+                if axis.get_scale() == 'linear':
+                    delta = (x1 - x0) * margin
+                    if do_lower_margin:
+                        x0 -= delta
+                    if do_upper_margin:
+                        x1 += delta
+                else:
+                    # If we have a non-linear scale, we need to
+                    # add the margin in figure space and then
+                    # transform back
+                    minpos = getattr(bb, minpos)
+                    transform = axis.get_transform()
+                    inverse_trans = transform.inverted()
+                    x0, x1 = axis._scale.limit_range_for_scale(
+                        x0, x1, minpos)
+                    x0t, x1t = transform.transform([x0, x1])
+                    delta = (x1t - x0t) * margin
+                    if do_lower_margin:
+                        x0t -= delta
+                    if do_upper_margin:
+                        x1t += delta
+                    x0, x1 = inverse_trans.transform([x0t, x1t])
+
+            if not _tight:
+                x0, x1 = locator.view_limits(x0, x1)
+            set_bound(x0, x1)
+            # End of definition of internal function 'handle_single_axis'.
 
         handle_single_axis(
             scalex, self._autoscaleXon, self._shared_x_axes,