Merge pull request #11388 from ImportanceOfBeingErnest/doc_constrained_layout_improvement

jklymak · web-flow · commit 9d8180964d75 · 2018-06-09T12:32:22.000-04:00
DOC: Constrained layout tutorial improvements
diff --git a/tutorials/intermediate/constrainedlayout_guide.py b/tutorials/intermediate/constrainedlayout_guide.py
@@ -9,8 +9,24 @@
 legends and colorbars so that they fit in the figure window while still
 preserving, as best they can, the logical layout requested by the user.
 
-*constrained_layout* is similar to *tight_layout*, but uses a constraint
-solver to determine the size of axes that allows them to fit.
+*constrained_layout* is similar to
+:doc:`tight_layout</tutorials/intermediate/tight_layout_guide>`,
+but uses a constraint solver to determine the size of axes that allows
+them to fit.
+
+*constrained_layout* needs to be activated before any axes are added to
+a figure. Two ways of doing so are
+
+* using the respective argument to :func:`~.pyplot.subplots` or
+  :func:`~.pyplot.figure`, e.g.::
+
+      plt.subplots(contrained_layout=True)
+
+* activate it via :ref:`rcParams<matplotlib-rcparams>`, like::
+
+      plt.rcParams['figure.constrained_layout.use'] = True
+
+Those are described in detail throughout the following sections.
 
 .. warning::
 
@@ -83,7 +99,7 @@ def example_plot(ax, fontsize=12, nodec=False):
     example_plot(ax)
 
 ###############################################################################
-# Specifying `constrained_layout=True` in the call to `plt.subplots`
+# Specifying ``constrained_layout=True`` in the call to ``plt.subplots``
 # causes the layout to be properly constrained.
 
 fig, axs = plt.subplots(2, 2, constrained_layout=True)
@@ -102,9 +118,9 @@ def example_plot(ax, fontsize=12, nodec=False):
 #
 # .. note::
 #
-#   For the `pcolormesh` kwargs (``pc_kwargs``) we use a dictionary.
+#   For the `~.axes.Axes.pcolormesh` kwargs (``pc_kwargs``) we use a dictionary.
 #   Below we will assign one colorbar to a number of axes each containing
-#   a `ScalarMappable`; specifying the norm and colormap ensures
+#   a `~.cm.ScalarMappable`; specifying the norm and colormap ensures
 #   the colorbar is accurate for all the axes.
 
 arr = np.arange(100).reshape((10, 10))
@@ -117,7 +133,8 @@ def example_plot(ax, fontsize=12, nodec=False):
 
 ############################################################################
 # If you specify a list of axes (or other iterable container) to the
-# ``ax`` argument of ``colorbar``, constrained_layout will take space from all # axes that share the same gridspec.
+# ``ax`` argument of ``colorbar``, constrained_layout will take space from all
+# axes that share the same gridspec.
 
 fig, axs = plt.subplots(2, 2, figsize=(4, 4), constrained_layout=True)
 for ax in axs.flatten():
@@ -153,7 +170,7 @@ def example_plot(ax, fontsize=12, nodec=False):
 # Suptitle
 # =========
 #
-# ``constrained_layout`` can also make room for ``suptitle``.
+# ``constrained_layout`` can also make room for `~.figure.Figure.suptitle`.
 
 fig, axs = plt.subplots(2, 2, figsize=(4, 4), constrained_layout=True)
 for ax in axs.flatten():
@@ -165,10 +182,10 @@ def example_plot(ax, fontsize=12, nodec=False):
 # Legends
 # =======
 #
-# Legends can be placed outside
-# of their parent axis.  Constrained-layout is designed to handle this.
+# Legends can be placed outside of their parent axis.
+# Constrained-layout is designed to handle this for :meth:`.Axes.legend`.
 # However, constrained-layout does *not* handle legends being created via
-# ``fig.legend()`` (yet).
+# :meth:`.Figure.legend` (yet).
 
 fig, ax = plt.subplots(constrained_layout=True)
 ax.plot(np.arange(10), label='This is a plot')
@@ -190,8 +207,8 @@ def example_plot(ax, fontsize=12, nodec=False):
 # For constrained_layout, we have implemented a padding around the edge of
 # each axes.  This padding sets the distance from the edge of the plot,
 # and the minimum distance between adjacent plots.  It is specified in
-# inches by the keyword arguments `w_pad` and `h_pad` to the function
-# `fig.set_constrained_layout_pads`:
+# inches by the keyword arguments ``w_pad`` and ``h_pad`` to the function
+# `~.figure.Figure.set_constrained_layout_pads`:
 
 fig, axs = plt.subplots(2, 2, constrained_layout=True)
 for ax in axs.flatten():
@@ -210,7 +227,7 @@ def example_plot(ax, fontsize=12, nodec=False):
         hspace=0., wspace=0.)
 
 ##########################################
-# Spacing between subplots is set by `wspace` and `hspace`.  There are
+# Spacing between subplots is set by ``wspace`` and ``hspace``. There are
 # specified as a fraction of the size of the subplot group as a whole.
 # If the size of the figure is changed, then these spaces change in
 # proportion.  Note in the blow how the space at the edges doesn't change from
@@ -229,10 +246,10 @@ def example_plot(ax, fontsize=12, nodec=False):
 # Spacing with colorbars
 # -----------------------
 #
-# Colorbars still respect the `w_pad` and `h_pad` values.  However they will
-# be `wspace` and `hsapce` apart from other subplots.  Note the use of a `pad`
-# kwarg here in the `colorbar` call.  It defaults to 0.02 of the size of the
-# axis it is attached to.
+# Colorbars still respect the ``w_pad`` and ``h_pad`` values. However they will
+# be ``wspace`` and ``hsapce`` apart from other subplots.  Note the use of a
+# ``pad`` kwarg here in the ``colorbar`` call.  It defaults to 0.02 of the size
+# of the axis it is attached to.
 
 fig, axs = plt.subplots(2, 2, constrained_layout=True)
 for ax in axs.flatten():
@@ -246,7 +263,7 @@ def example_plot(ax, fontsize=12, nodec=False):
 ##########################################
 # In the above example, the colorbar will not ever be closer than 2 pts to
 # the plot, but if we want it a bit further away, we can specify its value
-# for `pad` to be non-zero.
+# for ``pad`` to be non-zero.
 
 fig, axs = plt.subplots(2, 2, constrained_layout=True)
 for ax in axs.flatten():
@@ -259,16 +276,16 @@ def example_plot(ax, fontsize=12, nodec=False):
 
 ##########################################
 # rcParams
-# --------
+# ========
 #
-# There are five `rcParams` that can be set, either in a script
-# or in the `matplotlibrc` file.  They all have the prefix
-# `figure.constrained_layout`:
+# There are five :ref:`rcParams<matplotlib-rcparams>` that can be set,
+# either in a script or in the `matplotlibrc` file.
+# They all have the prefix ``figure.constrained_layout``:
 #
-# - `use`: Whether to use constrained_layout. Default is False
-# - `w_pad`, `h_pad`    Padding around axes objects.
+# - ``use``: Whether to use constrained_layout. Default is False
+# - ``w_pad``, ``h_pad``:    Padding around axes objects.
 #    Float representing inches.  Default is 3./72. inches (3 pts)
-# - `wspace`, `hspace`  Space between subplot groups.
+# - ``wspace``, ``hspace``:  Space between subplot groups.
 #    Float representing a fraction of the subplot widths being separated.
 #    Default is 0.02.
 
@@ -296,7 +313,7 @@ def example_plot(ax, fontsize=12, nodec=False):
 example_plot(ax2)
 
 ###############################################################################
-# More complicated gridspec layouts are possible...
+# More complicated gridspec layouts are possible.
 
 fig = plt.figure(constrained_layout=True)
 
@@ -377,17 +394,17 @@ def docomplicated(suptitle=None):
 # ================================
 #
 # There can be good reasons to manually set an axes position.  A manual call
-# to `ax.set_position()` will set the axes so constrained_layout has no
-# effect on it anymore.  (Note that constrained_layout still leaves the space
-# for the axes that is moved).
+# to `~.axes.Axes.set_position` will set the axes so constrained_layout has
+# no effect on it anymore. (Note that constrained_layout still leaves the
+# space for the axes that is moved).
 
 fig, axs = plt.subplots(1, 2, constrained_layout=True)
 example_plot(axs[0], fontsize=12)
 axs[1].set_position([0.2, 0.2, 0.4, 0.4])
 
 ###############################################################################
 # If you want an inset axes in data-space, you need to manually execute the
-# layout using `fig.execute_constrained_layout()` call.  The inset figure
+# layout using ``fig.execute_constrained_layout()`` call.  The inset figure
 # will then be properly positioned.  However, it will not be properly
 # positioned if the size of the figure is subsequently changed.  Similarly,
 # if the figure is printed to another backend, there may be slight changes
@@ -414,7 +431,7 @@ def docomplicated(suptitle=None):
 #
 # ``constrained_layout`` will not work on subplots
 # created via the `subplot` command.  The reason is that each of these
-# commands creates a separate `GridSpec` instance and `constrained_layout`
+# commands creates a separate `GridSpec` instance and ``constrained_layout``
 # uses (nested) gridspecs to carry out the layout.  So the following fails
 # to yield a nice layout:
 
@@ -520,33 +537,33 @@ def docomplicated(suptitle=None):
 #
 # Figures are laid out in a hierarchy:
 #
-# 1. Figure: `fig = plt.figure()`
+# 1. Figure: ``fig = plt.figure()``
 #
-#   a. Gridspec `gs0 = gridspec.GridSpec(1, 2, figure=fig)`
+#   a. Gridspec ``gs0 = gridspec.GridSpec(1, 2, figure=fig)``
 #
-#       i. Subplotspec: `ss = gs[0, 0]`
+#       i. Subplotspec: ``ss = gs[0, 0]``
 #
-#          1. Axes: `ax0 = fig.add_subplot(ss)`
+#          1. Axes: ``ax0 = fig.add_subplot(ss)``
 #
-#       ii. Subplotspec: `ss = gs[0, 1]`
+#       ii. Subplotspec: ``ss = gs[0, 1]``
 #
-#          1. Gridspec: `gsR = gridspec.GridSpecFromSubplotSpec(2, 1, ss)`
+#          1. Gridspec: ``gsR = gridspec.GridSpecFromSubplotSpec(2, 1, ss)``
 #
-#             - Subplotspec: ss = gsR[0, 0]
+#             - Subplotspec: ``ss = gsR[0, 0]``
 #
-#                - Axes: `axR0 = fig.add_subplot(ss)`
+#                - Axes: ``axR0 = fig.add_subplot(ss)``
 #
-#             - Subplotspec: ss = gsR[1, 0]
+#             - Subplotspec: ``ss = gsR[1, 0]``
 #
-#                - Axes: `axR1 = fig.add_subplot(ss)`
+#                - Axes: ``axR1 = fig.add_subplot(ss)``
 #
 # Each item has a layoutbox associated with it. The nesting of gridspecs
 # created with `.GridSpecFromSubplotSpec` can be arbitrarily deep.
 #
-# Each ``~matplotlib.axes.Axes` has *two* layoutboxes.  The first one,
+# Each `~matplotlib.axes.Axes` has *two* layoutboxes.  The first one,
 # ``ax._layoutbox`` represents the outside of the Axes and all its
 # decorations (i.e. ticklabels,axis labels, etc.).
-# The second layoutbox corresponds to the Axes' `ax.position`, which sets
+# The second layoutbox corresponds to the Axes' ``ax.position``, which sets
 # where in the figure the spines are placed.
 #
 # Why so many stacked containers?  Ideally, all that would be needed are the
@@ -569,8 +586,8 @@ def docomplicated(suptitle=None):
 # the difference between the red ``pos`` box and the green ``ax`` box
 # is set by the size of the decorations around the Axes.
 #
-# In the code, this is accomplished by the entries in `.do_constrained_layout`
-# like::
+# In the code, this is accomplished by the entries in
+# ``do_constrained_layout()`` like::
 #
 #     ax._poslayoutbox.edit_left_margin_min(-bbox.x0 + pos.x0 + w_padt)
 #
@@ -589,7 +606,7 @@ def docomplicated(suptitle=None):
 # much smaller than the left-hand, so the right-hand layoutboxes are smaller.
 #
 # The Subplotspec boxes are laid out in the code in the subroutine
-# `.arange_subplotspecs`, which simply checks the subplotspecs in the code
+# ``arange_subplotspecs()``, which simply checks the subplotspecs in the code
 # against one another and stacks them appropriately.
 #
 # The two ``pos`` axes are lined up.  Because they have the same
@@ -627,10 +644,10 @@ def docomplicated(suptitle=None):
 # number of columns (one in this example).
 #
 # The colorbar layout logic is contained in `~matplotlib.colorbar.make_axes`
-# which calls `._constrained_layout.layoutcolorbarsingle`
+# which calls ``_constrained_layout.layoutcolorbarsingle()``
 # for cbars attached to a single axes, and
-# `._constrained_layout.layoutcolorbargridspec` if the colorbar is associated
-# with a gridspec.
+# ``_constrained_layout.layoutcolorbargridspec()`` if the colorbar is
+# associated with a gridspec.
 
 fig, ax = plt.subplots(1, 2, constrained_layout=True)
 im = ax[0].pcolormesh(arr, **pc_kwargs)
@@ -644,7 +661,7 @@ def docomplicated(suptitle=None):
 #
 # This example shows the Subplotspec layoutboxes being made smaller by
 # a colorbar layoutbox.  The size of the colorbar layoutbox is
-# set to be *shrink* smaller than the vertical extent of the ``pos``
+# set to be ``shrink`` smaller than the vertical extent of the ``pos``
 # layoutboxes in the gridspec, and it is made to be centered between
 # those two points.
 
@@ -713,7 +730,7 @@ def docomplicated(suptitle=None):
 # the axes position in made the same size as the occupied Axes positions.
 #
 # This is done at the start of
-# `~._constrained_layout.do_constrained_layout` (``hassubplotspec``).
+# ``_constrained_layout.do_constrained_layout()`` (``hassubplotspec``).
 
 fig = plt.figure(constrained_layout=True)
 gs = gridspec.GridSpec(1, 3, figure=fig)
diff --git a/tutorials/intermediate/tight_layout_guide.py b/tutorials/intermediate/tight_layout_guide.py
@@ -10,6 +10,9 @@
 feature and may not work for some cases. It only checks the extents
 of ticklabels, axis labels, and titles.
 
+An alternative to *tight_layout* is 
+:doc:`constrained_layout</tutorials/intermediate/constrainedlayout_guide>`.
+
 
 Simple Example
 ==============
diff --git a/tutorials/introductory/customizing.py b/tutorials/introductory/customizing.py
@@ -91,6 +91,8 @@
 plt.show()
 
 ###############################################################################
+# .. _matplotlib-rcparams:
+#
 # matplotlib rcParams
 # ===================
 #

Original file line number	Diff line number	Diff line change
`@@ -91,6 +91,8 @@`
`91`	`91`	`plt.show()`
`92`	`92`
`93`	`93`	`###############################################################################`
	`94`	`+# .. _matplotlib-rcparams:`
	`95`	`+#`
`94`	`96`	`# matplotlib rcParams`
`95`	`97`	`# ===================`
`96`	`98`	`#`