.. DO NOT EDIT. .. THIS FILE WAS AUTOMATICALLY GENERATED BY SPHINX-GALLERY. .. TO MAKE CHANGES, EDIT THE SOURCE PYTHON FILE: .. "tutorials/intermediate/constrainedlayout_guide.py" .. LINE NUMBERS ARE GIVEN BELOW. .. only:: html .. note:: :class: sphx-glr-download-link-note Click :ref:`here ` to download the full example code .. rst-class:: sphx-glr-example-title .. _sphx_glr_tutorials_intermediate_constrainedlayout_guide.py: ================================ Constrained Layout Guide ================================ How to use constrained-layout to fit plots within your figure cleanly. *constrained_layout* automatically adjusts subplots and decorations like 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 :doc:`tight_layout`, 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(constrained_layout=True) * activate it via :ref:`rcParams`, like:: plt.rcParams['figure.constrained_layout.use'] = True Those are described in detail throughout the following sections. .. warning:: Currently Constrained Layout is **experimental**. The behaviour and API are subject to change, or the whole functionality may be removed without a deprecation period. If you *require* your plots to be absolutely reproducible, get the Axes positions after running Constrained Layout and use ``ax.set_position()`` in your code with ``constrained_layout=False``. Simple Example ============== In Matplotlib, the location of axes (including subplots) are specified in normalized figure coordinates. It can happen that your axis labels or titles (or sometimes even ticklabels) go outside the figure area, and are thus clipped. .. GENERATED FROM PYTHON SOURCE LINES 48-78 .. code-block:: default import matplotlib.pyplot as plt import matplotlib.colors as mcolors import matplotlib.gridspec as gridspec import numpy as np plt.rcParams['savefig.facecolor'] = "0.8" plt.rcParams['figure.figsize'] = 4.5, 4. plt.rcParams['figure.max_open_warning'] = 50 def example_plot(ax, fontsize=12, hide_labels=False): ax.plot([1, 2]) ax.locator_params(nbins=3) if hide_labels: ax.set_xticklabels([]) ax.set_yticklabels([]) else: ax.set_xlabel('x-label', fontsize=fontsize) ax.set_ylabel('y-label', fontsize=fontsize) ax.set_title('Title', fontsize=fontsize) fig, ax = plt.subplots(constrained_layout=False) example_plot(ax, fontsize=24) .. image:: /tutorials/intermediate/images/sphx_glr_constrainedlayout_guide_001.png :alt: Title :class: sphx-glr-single-img .. GENERATED FROM PYTHON SOURCE LINES 80-84 To prevent this, the location of axes needs to be adjusted. For subplots, this can be done by adjusting the subplot params (:ref:`howto-subplots-adjust`). However, specifying your figure with the ``constrained_layout=True`` kwarg will do the adjusting automatically. .. GENERATED FROM PYTHON SOURCE LINES 84-88 .. code-block:: default fig, ax = plt.subplots(constrained_layout=True) example_plot(ax, fontsize=24) .. image:: /tutorials/intermediate/images/sphx_glr_constrainedlayout_guide_002.png :alt: Title :class: sphx-glr-single-img .. GENERATED FROM PYTHON SOURCE LINES 89-91 When you have multiple subplots, often you see labels of different axes overlapping each other. .. GENERATED FROM PYTHON SOURCE LINES 91-96 .. code-block:: default fig, axs = plt.subplots(2, 2, constrained_layout=False) for ax in axs.flat: example_plot(ax) .. image:: /tutorials/intermediate/images/sphx_glr_constrainedlayout_guide_003.png :alt: Title, Title, Title, Title :class: sphx-glr-single-img .. GENERATED FROM PYTHON SOURCE LINES 97-99 Specifying ``constrained_layout=True`` in the call to ``plt.subplots`` causes the layout to be properly constrained. .. GENERATED FROM PYTHON SOURCE LINES 99-104 .. code-block:: default fig, axs = plt.subplots(2, 2, constrained_layout=True) for ax in axs.flat: example_plot(ax) .. image:: /tutorials/intermediate/images/sphx_glr_constrainedlayout_guide_004.png :alt: Title, Title, Title, Title :class: sphx-glr-single-img .. GENERATED FROM PYTHON SOURCE LINES 105-120 Colorbars ========= If you create a colorbar with `.Figure.colorbar`, you need to make room for it. ``constrained_layout`` does this automatically. Note that if you specify ``use_gridspec=True`` it will be ignored because this option is made for improving the layout via ``tight_layout``. .. note:: 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 `~.cm.ScalarMappable`; specifying the norm and colormap ensures the colorbar is accurate for all the axes. .. GENERATED FROM PYTHON SOURCE LINES 120-129 .. code-block:: default arr = np.arange(100).reshape((10, 10)) norm = mcolors.Normalize(vmin=0., vmax=100.) # see note above: this makes all pcolormesh calls consistent: pc_kwargs = {'rasterized': True, 'cmap': 'viridis', 'norm': norm} fig, ax = plt.subplots(figsize=(4, 4), constrained_layout=True) im = ax.pcolormesh(arr, **pc_kwargs) fig.colorbar(im, ax=ax, shrink=0.6) .. image:: /tutorials/intermediate/images/sphx_glr_constrainedlayout_guide_005.png :alt: constrainedlayout guide :class: sphx-glr-single-img .. rst-class:: sphx-glr-script-out Out: .. code-block:: none .. GENERATED FROM PYTHON SOURCE LINES 130-133 If you specify a list of axes (or other iterable container) to the ``ax`` argument of ``colorbar``, constrained_layout will take space from the specified axes. .. GENERATED FROM PYTHON SOURCE LINES 133-139 .. code-block:: default fig, axs = plt.subplots(2, 2, figsize=(4, 4), constrained_layout=True) for ax in axs.flat: im = ax.pcolormesh(arr, **pc_kwargs) fig.colorbar(im, ax=axs, shrink=0.6) .. image:: /tutorials/intermediate/images/sphx_glr_constrainedlayout_guide_006.png :alt: constrainedlayout guide :class: sphx-glr-single-img .. rst-class:: sphx-glr-script-out Out: .. code-block:: none .. GENERATED FROM PYTHON SOURCE LINES 140-143 If you specify a list of axes from inside a grid of axes, the colorbar will steal space appropriately, and leave a gap, but all subplots will still be the same size. .. GENERATED FROM PYTHON SOURCE LINES 143-150 .. code-block:: default fig, axs = plt.subplots(3, 3, figsize=(4, 4), constrained_layout=True) for ax in axs.flat: im = ax.pcolormesh(arr, **pc_kwargs) fig.colorbar(im, ax=axs[1:, ][:, 1], shrink=0.8) fig.colorbar(im, ax=axs[:, -1], shrink=0.6) .. image:: /tutorials/intermediate/images/sphx_glr_constrainedlayout_guide_007.png :alt: constrainedlayout guide :class: sphx-glr-single-img .. rst-class:: sphx-glr-script-out Out: .. code-block:: none .. GENERATED FROM PYTHON SOURCE LINES 151-156 Note that there is a bit of a subtlety when specifying a single axes as the parent. In the following, it might be desirable and expected for the colorbars to line up, but they don't because the colorbar paired with the bottom axes is tied to the subplotspec of the axes, and hence shrinks when the gridspec-level colorbar is added. .. GENERATED FROM PYTHON SOURCE LINES 156-164 .. code-block:: default fig, axs = plt.subplots(3, 1, figsize=(4, 4), constrained_layout=True) for ax in axs[:2]: im = ax.pcolormesh(arr, **pc_kwargs) fig.colorbar(im, ax=axs[:2], shrink=0.6) im = axs[2].pcolormesh(arr, **pc_kwargs) fig.colorbar(im, ax=axs[2], shrink=0.6) .. image:: /tutorials/intermediate/images/sphx_glr_constrainedlayout_guide_008.png :alt: constrainedlayout guide :class: sphx-glr-single-img .. rst-class:: sphx-glr-script-out Out: .. code-block:: none .. GENERATED FROM PYTHON SOURCE LINES 165-167 The API to make a single-axes behave like a list of axes is to specify it as a list (or other iterable container), as below: .. GENERATED FROM PYTHON SOURCE LINES 167-175 .. code-block:: default fig, axs = plt.subplots(3, 1, figsize=(4, 4), constrained_layout=True) for ax in axs[:2]: im = ax.pcolormesh(arr, **pc_kwargs) fig.colorbar(im, ax=axs[:2], shrink=0.6) im = axs[2].pcolormesh(arr, **pc_kwargs) fig.colorbar(im, ax=[axs[2]], shrink=0.6) .. image:: /tutorials/intermediate/images/sphx_glr_constrainedlayout_guide_009.png :alt: constrainedlayout guide :class: sphx-glr-single-img .. rst-class:: sphx-glr-script-out Out: .. code-block:: none .. GENERATED FROM PYTHON SOURCE LINES 176-180 Suptitle ========= ``constrained_layout`` can also make room for `~.figure.Figure.suptitle`. .. GENERATED FROM PYTHON SOURCE LINES 180-187 .. code-block:: default fig, axs = plt.subplots(2, 2, figsize=(4, 4), constrained_layout=True) for ax in axs.flat: im = ax.pcolormesh(arr, **pc_kwargs) fig.colorbar(im, ax=axs, shrink=0.6) fig.suptitle('Big Suptitle') .. image:: /tutorials/intermediate/images/sphx_glr_constrainedlayout_guide_010.png :alt: Big Suptitle :class: sphx-glr-single-img .. rst-class:: sphx-glr-script-out Out: .. code-block:: none Text(0.5, 0.9895825, 'Big Suptitle') .. GENERATED FROM PYTHON SOURCE LINES 188-195 Legends ======= 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 :meth:`.Figure.legend` (yet). .. GENERATED FROM PYTHON SOURCE LINES 195-200 .. code-block:: default fig, ax = plt.subplots(constrained_layout=True) ax.plot(np.arange(10), label='This is a plot') ax.legend(loc='center left', bbox_to_anchor=(0.8, 0.5)) .. image:: /tutorials/intermediate/images/sphx_glr_constrainedlayout_guide_011.png :alt: constrainedlayout guide :class: sphx-glr-single-img .. rst-class:: sphx-glr-script-out Out: .. code-block:: none .. GENERATED FROM PYTHON SOURCE LINES 201-202 However, this will steal space from a subplot layout: .. GENERATED FROM PYTHON SOURCE LINES 202-208 .. code-block:: default fig, axs = plt.subplots(1, 2, figsize=(4, 2), constrained_layout=True) axs[0].plot(np.arange(10)) axs[1].plot(np.arange(10), label='This is a plot') axs[1].legend(loc='center left', bbox_to_anchor=(0.8, 0.5)) .. image:: /tutorials/intermediate/images/sphx_glr_constrainedlayout_guide_012.png :alt: constrainedlayout guide :class: sphx-glr-single-img .. rst-class:: sphx-glr-script-out Out: .. code-block:: none .. GENERATED FROM PYTHON SOURCE LINES 209-218 In order for a legend or other artist to *not* steal space from the subplot layout, we can ``leg.set_in_layout(False)``. Of course this can mean the legend ends up cropped, but can be useful if the plot is subsequently called with ``fig.savefig('outname.png', bbox_inches='tight')``. Note, however, that the legend's ``get_in_layout`` status will have to be toggled again to make the saved file work, and we must manually trigger a draw if we want constrained_layout to adjust the size of the axes before printing. .. GENERATED FROM PYTHON SOURCE LINES 218-235 .. code-block:: default fig, axs = plt.subplots(1, 2, figsize=(4, 2), constrained_layout=True) axs[0].plot(np.arange(10)) axs[1].plot(np.arange(10), label='This is a plot') leg = axs[1].legend(loc='center left', bbox_to_anchor=(0.8, 0.5)) leg.set_in_layout(False) # trigger a draw so that constrained_layout is executed once # before we turn it off when printing.... fig.canvas.draw() # we want the legend included in the bbox_inches='tight' calcs. leg.set_in_layout(True) # we don't want the layout to change at this point. fig.set_constrained_layout(False) fig.savefig('../../doc/_static/constrained_layout_1b.png', bbox_inches='tight', dpi=100) .. image:: /tutorials/intermediate/images/sphx_glr_constrainedlayout_guide_013.png :alt: constrainedlayout guide :class: sphx-glr-single-img .. GENERATED FROM PYTHON SOURCE LINES 236-243 The saved file looks like: .. image:: /_static/constrained_layout_1b.png :align: center A better way to get around this awkwardness is to simply use the legend method provided by `.Figure.legend`: .. GENERATED FROM PYTHON SOURCE LINES 243-252 .. code-block:: default fig, axs = plt.subplots(1, 2, figsize=(4, 2), constrained_layout=True) axs[0].plot(np.arange(10)) lines = axs[1].plot(np.arange(10), label='This is a plot') labels = [l.get_label() for l in lines] leg = fig.legend(lines, labels, loc='center left', bbox_to_anchor=(0.8, 0.5), bbox_transform=axs[1].transAxes) fig.savefig('../../doc/_static/constrained_layout_2b.png', bbox_inches='tight', dpi=100) .. image:: /tutorials/intermediate/images/sphx_glr_constrainedlayout_guide_014.png :alt: constrainedlayout guide :class: sphx-glr-single-img .. GENERATED FROM PYTHON SOURCE LINES 253-258 The saved file looks like: .. image:: /_static/constrained_layout_2b.png :align: center .. GENERATED FROM PYTHON SOURCE LINES 260-268 Padding and Spacing =================== 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 `~.figure.Figure.set_constrained_layout_pads`: .. GENERATED FROM PYTHON SOURCE LINES 268-279 .. code-block:: default fig, axs = plt.subplots(2, 2, constrained_layout=True) for ax in axs.flat: example_plot(ax, hide_labels=True) fig.set_constrained_layout_pads(w_pad=4/72, h_pad=4/72, hspace=0, wspace=0) fig, axs = plt.subplots(2, 2, constrained_layout=True) for ax in axs.flat: example_plot(ax, hide_labels=True) fig.set_constrained_layout_pads(w_pad=2/72, h_pad=2/72, hspace=0, wspace=0) .. rst-class:: sphx-glr-horizontal * .. image:: /tutorials/intermediate/images/sphx_glr_constrainedlayout_guide_015.png :alt: constrainedlayout guide :class: sphx-glr-multi-img * .. image:: /tutorials/intermediate/images/sphx_glr_constrainedlayout_guide_016.png :alt: constrainedlayout guide :class: sphx-glr-multi-img .. GENERATED FROM PYTHON SOURCE LINES 280-285 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 below how the space at the edges doesn't change from the above, but the space between subplots does. .. GENERATED FROM PYTHON SOURCE LINES 285-292 .. code-block:: default fig, axs = plt.subplots(2, 2, constrained_layout=True) for ax in axs.flat: example_plot(ax, hide_labels=True) fig.set_constrained_layout_pads(w_pad=2/72, h_pad=2/72, hspace=0.2, wspace=0.2) .. image:: /tutorials/intermediate/images/sphx_glr_constrainedlayout_guide_017.png :alt: constrainedlayout guide :class: sphx-glr-single-img .. GENERATED FROM PYTHON SOURCE LINES 293-302 Spacing with colorbars ----------------------- Colorbars will be placed ``wspace`` and ``hsapce`` apart from other subplots. The padding between the colorbar and the axis it is attached to will never be less than ``w_pad`` (for a vertical colorbar) or ``h_pad`` (for a horizontal colorbar). Note the use of the ``pad`` kwarg here in the ``colorbar`` call. It defaults to 0.02 of the size of the axis it is attached to. .. GENERATED FROM PYTHON SOURCE LINES 302-311 .. code-block:: default fig, axs = plt.subplots(2, 2, constrained_layout=True) for ax in axs.flat: pc = ax.pcolormesh(arr, **pc_kwargs) fig.colorbar(pc, ax=ax, shrink=0.6, pad=0) ax.set_xticklabels('') ax.set_yticklabels('') fig.set_constrained_layout_pads(w_pad=2/72, h_pad=2/72, hspace=0.2, wspace=0.2) .. image:: /tutorials/intermediate/images/sphx_glr_constrainedlayout_guide_018.png :alt: constrainedlayout guide :class: sphx-glr-single-img .. GENERATED FROM PYTHON SOURCE LINES 312-315 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. .. GENERATED FROM PYTHON SOURCE LINES 315-324 .. code-block:: default fig, axs = plt.subplots(2, 2, constrained_layout=True) for ax in axs.flat: pc = ax.pcolormesh(arr, **pc_kwargs) fig.colorbar(im, ax=ax, shrink=0.6, pad=0.05) ax.set_xticklabels('') ax.set_yticklabels('') fig.set_constrained_layout_pads(w_pad=2/72, h_pad=2/72, hspace=0.2, wspace=0.2) .. image:: /tutorials/intermediate/images/sphx_glr_constrainedlayout_guide_019.png :alt: constrainedlayout guide :class: sphx-glr-single-img .. GENERATED FROM PYTHON SOURCE LINES 325-338 rcParams ======== There are five :ref:`rcParams` that can be set, either in a script or in the :file:`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. Float representing inches. Default is 3./72. inches (3 pts) - ``wspace``, ``hspace``: Space between subplot groups. Float representing a fraction of the subplot widths being separated. Default is 0.02. .. GENERATED FROM PYTHON SOURCE LINES 338-344 .. code-block:: default plt.rcParams['figure.constrained_layout.use'] = True fig, axs = plt.subplots(2, 2, figsize=(3, 3)) for ax in axs.flat: example_plot(ax) .. image:: /tutorials/intermediate/images/sphx_glr_constrainedlayout_guide_020.png :alt: Title, Title, Title, Title :class: sphx-glr-single-img .. GENERATED FROM PYTHON SOURCE LINES 345-354 Use with GridSpec ================= constrained_layout is meant to be used with :func:`~matplotlib.figure.Figure.subplots` or :func:`~matplotlib.gridspec.GridSpec` and :func:`~matplotlib.figure.Figure.add_subplot`. Note that in what follows ``constrained_layout=True`` .. GENERATED FROM PYTHON SOURCE LINES 354-364 .. code-block:: default fig = plt.figure() gs1 = gridspec.GridSpec(2, 1, figure=fig) ax1 = fig.add_subplot(gs1[0]) ax2 = fig.add_subplot(gs1[1]) example_plot(ax1) example_plot(ax2) .. image:: /tutorials/intermediate/images/sphx_glr_constrainedlayout_guide_021.png :alt: Title, Title :class: sphx-glr-single-img .. GENERATED FROM PYTHON SOURCE LINES 365-367 More complicated gridspec layouts are possible. Note here we use the convenience functions ``add_gridspec`` and ``subgridspec``. .. GENERATED FROM PYTHON SOURCE LINES 367-389 .. code-block:: default fig = plt.figure() gs0 = fig.add_gridspec(1, 2) gs1 = gs0[0].subgridspec(2, 1) ax1 = fig.add_subplot(gs1[0]) ax2 = fig.add_subplot(gs1[1]) example_plot(ax1) example_plot(ax2) gs2 = gs0[1].subgridspec(3, 1) for ss in gs2: ax = fig.add_subplot(ss) example_plot(ax) ax.set_title("") ax.set_xlabel("") ax.set_xlabel("x-label", fontsize=12) .. image:: /tutorials/intermediate/images/sphx_glr_constrainedlayout_guide_022.png :alt: Title, Title :class: sphx-glr-single-img .. rst-class:: sphx-glr-script-out Out: .. code-block:: none Text(0.5, 22.166999999999994, 'x-label') .. GENERATED FROM PYTHON SOURCE LINES 390-393 Note that in the above the left and columns don't have the same vertical extent. If we want the top and bottom of the two grids to line up then they need to be in the same gridspec: .. GENERATED FROM PYTHON SOURCE LINES 393-411 .. code-block:: default fig = plt.figure() gs0 = fig.add_gridspec(6, 2) ax1 = fig.add_subplot(gs0[:3, 0]) ax2 = fig.add_subplot(gs0[3:, 0]) example_plot(ax1) example_plot(ax2) ax = fig.add_subplot(gs0[0:2, 1]) example_plot(ax) ax = fig.add_subplot(gs0[2:4, 1]) example_plot(ax) ax = fig.add_subplot(gs0[4:, 1]) example_plot(ax) .. image:: /tutorials/intermediate/images/sphx_glr_constrainedlayout_guide_023.png :alt: Title, Title, Title, Title, Title :class: sphx-glr-single-img .. GENERATED FROM PYTHON SOURCE LINES 412-416 This example uses two gridspecs to have the colorbar only pertain to one set of pcolors. Note how the left column is wider than the two right-hand columns because of this. Of course, if you wanted the subplots to be the same size you only needed one gridspec. .. GENERATED FROM PYTHON SOURCE LINES 416-442 .. code-block:: default def docomplicated(suptitle=None): fig = plt.figure() gs0 = fig.add_gridspec(1, 2, figure=fig, width_ratios=[1., 2.]) gsl = gs0[0].subgridspec(2, 1) gsr = gs0[1].subgridspec(2, 2) for gs in gsl: ax = fig.add_subplot(gs) example_plot(ax) axs = [] for gs in gsr: ax = fig.add_subplot(gs) pcm = ax.pcolormesh(arr, **pc_kwargs) ax.set_xlabel('x-label') ax.set_ylabel('y-label') ax.set_title('title') axs += [ax] fig.colorbar(pcm, ax=axs) if suptitle is not None: fig.suptitle(suptitle) docomplicated() .. image:: /tutorials/intermediate/images/sphx_glr_constrainedlayout_guide_024.png :alt: Title, Title, title, title, title, title :class: sphx-glr-single-img .. GENERATED FROM PYTHON SOURCE LINES 443-450 Manually setting axes positions ================================ There can be good reasons to manually set an axes position. A manual call 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). .. GENERATED FROM PYTHON SOURCE LINES 450-455 .. code-block:: default fig, axs = plt.subplots(1, 2) example_plot(axs[0], fontsize=12) axs[1].set_position([0.2, 0.2, 0.4, 0.4]) .. image:: /tutorials/intermediate/images/sphx_glr_constrainedlayout_guide_025.png :alt: Title :class: sphx-glr-single-img .. GENERATED FROM PYTHON SOURCE LINES 456-462 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 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 of location due to small differences in how the backends render fonts. .. GENERATED FROM PYTHON SOURCE LINES 462-475 .. code-block:: default from matplotlib.transforms import Bbox fig, axs = plt.subplots(1, 2) example_plot(axs[0], fontsize=12) fig.execute_constrained_layout() # put into data-space: bb_data_ax2 = Bbox.from_bounds(0.5, 1., 0.2, 0.4) disp_coords = axs[0].transData.transform(bb_data_ax2) fig_coords_ax2 = fig.transFigure.inverted().transform(disp_coords) bb_ax2 = Bbox(fig_coords_ax2) ax2 = fig.add_axes(bb_ax2) .. image:: /tutorials/intermediate/images/sphx_glr_constrainedlayout_guide_026.png :alt: Title :class: sphx-glr-single-img .. GENERATED FROM PYTHON SOURCE LINES 476-502 Manually turning off ``constrained_layout`` =========================================== ``constrained_layout`` usually adjusts the axes positions on each draw of the figure. If you want to get the spacing provided by ``constrained_layout`` but not have it update, then do the initial draw and then call ``fig.set_constrained_layout(False)``. This is potentially useful for animations where the tick labels may change length. Note that ``constrained_layout`` is turned off for ``ZOOM`` and ``PAN`` GUI events for the backends that use the toolbar. This prevents the axes from changing position during zooming and panning. Limitations =========== Incompatible functions ---------------------- ``constrained_layout`` will not work on subplots created via `.pyplot.subplot`. The reason is that each call to `.pyplot.subplot` 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: .. GENERATED FROM PYTHON SOURCE LINES 502-513 .. code-block:: default fig = plt.figure() ax1 = plt.subplot(221) ax2 = plt.subplot(223) ax3 = plt.subplot(122) example_plot(ax1) example_plot(ax2) example_plot(ax3) .. image:: /tutorials/intermediate/images/sphx_glr_constrainedlayout_guide_027.png :alt: Title, Title, Title :class: sphx-glr-single-img .. GENERATED FROM PYTHON SOURCE LINES 514-515 Of course that layout is possible using a gridspec: .. GENERATED FROM PYTHON SOURCE LINES 515-527 .. code-block:: default fig = plt.figure() gs = fig.add_gridspec(2, 2) ax1 = fig.add_subplot(gs[0, 0]) ax2 = fig.add_subplot(gs[1, 0]) ax3 = fig.add_subplot(gs[:, 1]) example_plot(ax1) example_plot(ax2) example_plot(ax3) .. image:: /tutorials/intermediate/images/sphx_glr_constrainedlayout_guide_028.png :alt: Title, Title, Title :class: sphx-glr-single-img .. GENERATED FROM PYTHON SOURCE LINES 528-531 Similarly, :func:`~matplotlib.pyplot.subplot2grid` doesn't work for the same reason: each call creates a different parent gridspec. .. GENERATED FROM PYTHON SOURCE LINES 531-544 .. code-block:: default fig = plt.figure() ax1 = plt.subplot2grid((3, 3), (0, 0)) ax2 = plt.subplot2grid((3, 3), (0, 1), colspan=2) ax3 = plt.subplot2grid((3, 3), (1, 0), colspan=2, rowspan=2) ax4 = plt.subplot2grid((3, 3), (1, 2), rowspan=2) example_plot(ax1) example_plot(ax2) example_plot(ax3) example_plot(ax4) .. image:: /tutorials/intermediate/images/sphx_glr_constrainedlayout_guide_029.png :alt: Title, Title, Title, Title :class: sphx-glr-single-img .. GENERATED FROM PYTHON SOURCE LINES 545-547 The way to make this plot compatible with ``constrained_layout`` is again to use ``gridspec`` directly .. GENERATED FROM PYTHON SOURCE LINES 547-561 .. code-block:: default fig = plt.figure() gs = fig.add_gridspec(3, 3) ax1 = fig.add_subplot(gs[0, 0]) ax2 = fig.add_subplot(gs[0, 1:]) ax3 = fig.add_subplot(gs[1:, 0:2]) ax4 = fig.add_subplot(gs[1:, -1]) example_plot(ax1) example_plot(ax2) example_plot(ax3) example_plot(ax4) .. image:: /tutorials/intermediate/images/sphx_glr_constrainedlayout_guide_030.png :alt: Title, Title, Title, Title :class: sphx-glr-single-img .. GENERATED FROM PYTHON SOURCE LINES 562-581 Other Caveats ------------- * ``constrained_layout`` only considers ticklabels, axis labels, titles, and legends. Thus, other artists may be clipped and also may overlap. * It assumes that the extra space needed for ticklabels, axis labels, and titles is independent of original location of axes. This is often true, but there are rare cases where it is not. * There are small differences in how the backends handle rendering fonts, so the results will not be pixel-identical. * An artist using axes coordinates that extend beyond the axes boundary will result in unusual layouts when added to an axes. This can be avoided by adding the artist directly to the :class:`~matplotlib.figure.Figure` using :meth:`~matplotlib.figure.Figure.add_artist`. See :class:`~matplotlib.patches.ConnectionPatch` for an example. .. GENERATED FROM PYTHON SOURCE LINES 583-598 Debugging ========= Constrained-layout can fail in somewhat unexpected ways. Because it uses a constraint solver the solver can find solutions that are mathematically correct, but that aren't at all what the user wants. The usual failure mode is for all sizes to collapse to their smallest allowable value. If this happens, it is for one of two reasons: 1. There was not enough room for the elements you were requesting to draw. 2. There is a bug - in which case open an issue at https://github.com/matplotlib/matplotlib/issues. If there is a bug, please report with a self-contained example that does not require outside data or dependencies (other than numpy). .. GENERATED FROM PYTHON SOURCE LINES 600-665 Notes on the algorithm ====================== The algorithm for the constraint is relatively straightforward, but has some complexity due to the complex ways we can layout a figure. Figure layout ------------- Figures are laid out in a hierarchy: 1. Figure: ``fig = plt.figure()`` a. Gridspec ``gs0 = gridspec.GridSpec(1, 2, figure=fig)`` i. Subplotspec: ``ss = gs[0, 0]`` 1. Axes: ``ax0 = fig.add_subplot(ss)`` ii. Subplotspec: ``ss = gs[0, 1]`` 1. Gridspec: ``gsR = gridspec.GridSpecFromSubplotSpec(2, 1, ss)`` - Subplotspec: ``ss = gsR[0, 0]`` - Axes: ``axR0 = fig.add_subplot(ss)`` - Subplotspec: ``ss = gsR[1, 0]`` - 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, ``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 where in the figure the spines are placed. Why so many stacked containers? Ideally, all that would be needed are the Axes layout boxes. For the Gridspec case, a container is needed if the Gridspec is nested via `.GridSpecFromSubplotSpec`. At the top level, it is desirable for symmetry, but it also makes room for `~.Figure.suptitle`. For the Subplotspec/Axes case, Axes often have colorbars or other annotations that need to be packaged inside the Subplotspec, hence the need for the outer layer. Simple case: one Axes --------------------- For a single Axes the layout is straight forward. The Figure and outer Gridspec layoutboxes coincide. The Subplotspec and Axes boxes also coincide because the Axes has no colorbar. Note 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:: ax._poslayoutbox.edit_left_margin_min(-bbox.x0 + pos.x0 + w_padt) .. GENERATED FROM PYTHON SOURCE LINES 665-672 .. code-block:: default from matplotlib._layoutbox import plot_children fig, ax = plt.subplots(constrained_layout=True) example_plot(ax, fontsize=24) plot_children(fig, fig._layoutbox, printit=False) .. image:: /tutorials/intermediate/images/sphx_glr_constrainedlayout_guide_031.png :alt: Title :class: sphx-glr-single-img .. GENERATED FROM PYTHON SOURCE LINES 673-698 Simple case: two Axes --------------------- For this case, the Axes layoutboxes and the Subplotspec boxes still co-incide. However, because the decorations in the right-hand plot are so 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 against one another and stacks them appropriately. The two ``pos`` axes are lined up. Because they have the same minimum row, they are lined up at the top. Because they have the same maximum row they are lined up at the bottom. In the code this is accomplished via the calls to ``layoutbox.align``. If there was more than one row, then the same horizontal alignment would occur between the rows. The two ``pos`` axes are given the same width because the subplotspecs occupy the same number of columns. This is accomplished in the code where ``dcols0`` is compared to ``dcolsC``. If they are equal, then their widths are constrained to be equal. While it is a bit subtle in this case, note that the division between the Subplotspecs is *not* centered, but has been moved to the right to make space for the larger labels on the left-hand plot. .. GENERATED FROM PYTHON SOURCE LINES 698-704 .. code-block:: default fig, ax = plt.subplots(1, 2, constrained_layout=True) example_plot(ax[0], fontsize=32) example_plot(ax[1], fontsize=8) plot_children(fig, fig._layoutbox, printit=False) .. image:: /tutorials/intermediate/images/sphx_glr_constrainedlayout_guide_032.png :alt: Title, Title :class: sphx-glr-single-img .. GENERATED FROM PYTHON SOURCE LINES 705-722 Two Axes and colorbar --------------------- Adding a colorbar makes it clear why the Subplotspec layoutboxes must be different from the axes layoutboxes. Here we see the left-hand subplotspec has more room to accommodate the `~.Figure.colorbar`, and that there are two green ``ax`` boxes inside the ``ss`` box. Note that the width of the ``pos`` boxes is still the same because of the constraint on their widths because their subplotspecs occupy the same number of columns (one in this example). The colorbar layout logic is contained in `~matplotlib.colorbar.make_axes` which calls ``_constrained_layout.layoutcolorbarsingle()`` for cbars attached to a single axes, and ``_constrained_layout.layoutcolorbargridspec()`` if the colorbar is associated with a gridspec. .. GENERATED FROM PYTHON SOURCE LINES 722-729 .. code-block:: default fig, ax = plt.subplots(1, 2, constrained_layout=True) im = ax[0].pcolormesh(arr, **pc_kwargs) fig.colorbar(im, ax=ax[0], shrink=0.6) im = ax[1].pcolormesh(arr, **pc_kwargs) plot_children(fig, fig._layoutbox, printit=False) .. image:: /tutorials/intermediate/images/sphx_glr_constrainedlayout_guide_033.png :alt: constrainedlayout guide :class: sphx-glr-single-img .. GENERATED FROM PYTHON SOURCE LINES 730-738 Colorbar associated with a Gridspec ----------------------------------- 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`` layoutboxes in the gridspec, and it is made to be centered between those two points. .. GENERATED FROM PYTHON SOURCE LINES 738-745 .. code-block:: default fig, axs = plt.subplots(2, 2, constrained_layout=True) for ax in axs.flat: im = ax.pcolormesh(arr, **pc_kwargs) fig.colorbar(im, ax=axs, shrink=0.6) plot_children(fig, fig._layoutbox, printit=False) .. image:: /tutorials/intermediate/images/sphx_glr_constrainedlayout_guide_034.png :alt: constrainedlayout guide :class: sphx-glr-single-img .. GENERATED FROM PYTHON SOURCE LINES 746-763 Uneven sized Axes ----------------- There are two ways to make axes have an uneven size in a Gridspec layout, either by specifying them to cross Gridspecs rows or columns, or by specifying width and height ratios. The first method is used here. The constraint that makes the heights be correct is in the code where ``drowsC < drows0`` which in this case would be 1 is less than 2. So we constrain the height of the 1-row Axes to be less than half the height of the 2-row Axes. .. note:: This algorithm can be wrong if the decorations attached to the smaller axes are very large, so there is an unaccounted-for edge case. .. GENERATED FROM PYTHON SOURCE LINES 763-775 .. code-block:: default fig = plt.figure(constrained_layout=True) gs = gridspec.GridSpec(2, 2, figure=fig) ax = fig.add_subplot(gs[:, 0]) im = ax.pcolormesh(arr, **pc_kwargs) ax = fig.add_subplot(gs[0, 1]) im = ax.pcolormesh(arr, **pc_kwargs) ax = fig.add_subplot(gs[1, 1]) im = ax.pcolormesh(arr, **pc_kwargs) plot_children(fig, fig._layoutbox, printit=False) .. image:: /tutorials/intermediate/images/sphx_glr_constrainedlayout_guide_035.png :alt: constrainedlayout guide :class: sphx-glr-single-img .. GENERATED FROM PYTHON SOURCE LINES 776-779 Height and width ratios are accommodated with the same part of the code with the smaller axes always constrained to be less in size than the larger. .. GENERATED FROM PYTHON SOURCE LINES 779-793 .. code-block:: default fig = plt.figure(constrained_layout=True) gs = gridspec.GridSpec(3, 2, figure=fig, height_ratios=[1., 0.5, 1.5], width_ratios=[1.2, 0.8]) ax = fig.add_subplot(gs[:2, 0]) im = ax.pcolormesh(arr, **pc_kwargs) ax = fig.add_subplot(gs[2, 0]) im = ax.pcolormesh(arr, **pc_kwargs) ax = fig.add_subplot(gs[0, 1]) im = ax.pcolormesh(arr, **pc_kwargs) ax = fig.add_subplot(gs[1:, 1]) im = ax.pcolormesh(arr, **pc_kwargs) plot_children(fig, fig._layoutbox, printit=False) .. image:: /tutorials/intermediate/images/sphx_glr_constrainedlayout_guide_036.png :alt: constrainedlayout guide :class: sphx-glr-single-img .. GENERATED FROM PYTHON SOURCE LINES 794-804 Empty gridspec slots -------------------- The final piece of the code that has not been explained is what happens if there is an empty gridspec opening. In that case a fake invisible axes is added and we proceed as before. The empty gridspec has no decorations, but 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``). .. GENERATED FROM PYTHON SOURCE LINES 804-814 .. code-block:: default fig = plt.figure(constrained_layout=True) gs = gridspec.GridSpec(1, 3, figure=fig) ax = fig.add_subplot(gs[0]) im = ax.pcolormesh(arr, **pc_kwargs) ax = fig.add_subplot(gs[-1]) im = ax.pcolormesh(arr, **pc_kwargs) plot_children(fig, fig._layoutbox, printit=False) plt.show() .. image:: /tutorials/intermediate/images/sphx_glr_constrainedlayout_guide_037.png :alt: constrainedlayout guide :class: sphx-glr-single-img .. GENERATED FROM PYTHON SOURCE LINES 815-823 Other notes ----------- The layout is called only once. This is OK if the original layout was pretty close (which it should be in most cases). However, if the layout changes a lot from the default layout then the decorators can change size. In particular the x and ytick labels can change. If this happens, then we should probably call the whole routine twice. .. rst-class:: sphx-glr-timing **Total running time of the script:** ( 0 minutes 13.825 seconds) .. _sphx_glr_download_tutorials_intermediate_constrainedlayout_guide.py: .. only :: html .. container:: sphx-glr-footer :class: sphx-glr-footer-example .. container:: sphx-glr-download sphx-glr-download-python :download:`Download Python source code: constrainedlayout_guide.py ` .. container:: sphx-glr-download sphx-glr-download-jupyter :download:`Download Jupyter notebook: constrainedlayout_guide.ipynb ` .. only:: html .. rst-class:: sphx-glr-signature Keywords: matplotlib code example, codex, python plot, pyplot `Gallery generated by Sphinx-Gallery `_