Source code for matplotlib.gridspec

r"""
:mod:`~matplotlib.gridspec` contains classes that help to layout multiple
`~.axes.Axes` in a grid-like pattern within a figure.

The `GridSpec` specifies the overall grid structure. Individual cells within
the grid are referenced by `SubplotSpec`\s.

See the tutorial :doc:`/tutorials/intermediate/gridspec` for a comprehensive
usage guide.
"""

import copy
import logging
from numbers import Integral

import numpy as np

import matplotlib as mpl
from matplotlib import _api, _pylab_helpers, tight_layout, rcParams
from matplotlib.transforms import Bbox
import matplotlib._layoutgrid as layoutgrid


_log = logging.getLogger(__name__)


[docs]class GridSpecBase: """ A base class of GridSpec that specifies the geometry of the grid that a subplot will be placed. """ def __init__(self, nrows, ncols, height_ratios=None, width_ratios=None): """ Parameters ---------- nrows, ncols : int The number of rows and columns of the grid. width_ratios : array-like of length *ncols*, optional Defines the relative widths of the columns. Each column gets a relative width of ``width_ratios[i] / sum(width_ratios)``. If not given, all columns will have the same width. height_ratios : array-like of length *nrows*, optional Defines the relative heights of the rows. Each column gets a relative height of ``height_ratios[i] / sum(height_ratios)``. If not given, all rows will have the same height. """ if not isinstance(nrows, Integral) or nrows <= 0: raise ValueError( f"Number of rows must be a positive integer, not {nrows}") if not isinstance(ncols, Integral) or ncols <= 0: raise ValueError( f"Number of columns must be a positive integer, not {ncols}") self._nrows, self._ncols = nrows, ncols self.set_height_ratios(height_ratios) self.set_width_ratios(width_ratios) def __repr__(self): height_arg = (', height_ratios=%r' % (self._row_height_ratios,) if len(set(self._row_height_ratios)) != 1 else '') width_arg = (', width_ratios=%r' % (self._col_width_ratios,) if len(set(self._col_width_ratios)) != 1 else '') return '{clsname}({nrows}, {ncols}{optionals})'.format( clsname=self.__class__.__name__, nrows=self._nrows, ncols=self._ncols, optionals=height_arg + width_arg, ) nrows = property(lambda self: self._nrows, doc="The number of rows in the grid.") ncols = property(lambda self: self._ncols, doc="The number of columns in the grid.")
[docs] def get_geometry(self): """ Return a tuple containing the number of rows and columns in the grid. """ return self._nrows, self._ncols
[docs] def get_subplot_params(self, figure=None): # Must be implemented in subclasses pass
[docs] def new_subplotspec(self, loc, rowspan=1, colspan=1): """ Create and return a `.SubplotSpec` instance. Parameters ---------- loc : (int, int) The position of the subplot in the grid as ``(row_index, column_index)``. rowspan, colspan : int, default: 1 The number of rows and columns the subplot should span in the grid. """ loc1, loc2 = loc subplotspec = self[loc1:loc1+rowspan, loc2:loc2+colspan] return subplotspec
[docs] def set_width_ratios(self, width_ratios): """ Set the relative widths of the columns. *width_ratios* must be of length *ncols*. Each column gets a relative width of ``width_ratios[i] / sum(width_ratios)``. """ if width_ratios is None: width_ratios = [1] * self._ncols elif len(width_ratios) != self._ncols: raise ValueError('Expected the given number of width ratios to ' 'match the number of columns of the grid') self._col_width_ratios = width_ratios
[docs] def get_width_ratios(self): """ Return the width ratios. This is *None* if no width ratios have been set explicitly. """ return self._col_width_ratios
[docs] def set_height_ratios(self, height_ratios): """ Set the relative heights of the rows. *height_ratios* must be of length *nrows*. Each row gets a relative height of ``height_ratios[i] / sum(height_ratios)``. """ if height_ratios is None: height_ratios = [1] * self._nrows elif len(height_ratios) != self._nrows: raise ValueError('Expected the given number of height ratios to ' 'match the number of rows of the grid') self._row_height_ratios = height_ratios
[docs] def get_height_ratios(self): """ Return the height ratios. This is *None* if no height ratios have been set explicitly. """ return self._row_height_ratios
[docs] def get_grid_positions(self, fig, raw=False): """ Return the positions of the grid cells in figure coordinates. Parameters ---------- fig : `~matplotlib.figure.Figure` The figure the grid should be applied to. The subplot parameters (margins and spacing between subplots) are taken from *fig*. raw : bool, default: False If *True*, the subplot parameters of the figure are not taken into account. The grid spans the range [0, 1] in both directions without margins and there is no space between grid cells. This is used for constrained_layout. Returns ------- bottoms, tops, lefts, rights : array The bottom, top, left, right positions of the grid cells in figure coordinates. """ nrows, ncols = self.get_geometry() if raw: left = 0. right = 1. bottom = 0. top = 1. wspace = 0. hspace = 0. else: subplot_params = self.get_subplot_params(fig) left = subplot_params.left right = subplot_params.right bottom = subplot_params.bottom top = subplot_params.top wspace = subplot_params.wspace hspace = subplot_params.hspace tot_width = right - left tot_height = top - bottom # calculate accumulated heights of columns cell_h = tot_height / (nrows + hspace*(nrows-1)) sep_h = hspace * cell_h norm = cell_h * nrows / sum(self._row_height_ratios) cell_heights = [r * norm for r in self._row_height_ratios] sep_heights = [0] + ([sep_h] * (nrows-1)) cell_hs = np.cumsum(np.column_stack([sep_heights, cell_heights]).flat) # calculate accumulated widths of rows cell_w = tot_width / (ncols + wspace*(ncols-1)) sep_w = wspace * cell_w norm = cell_w * ncols / sum(self._col_width_ratios) cell_widths = [r * norm for r in self._col_width_ratios] sep_widths = [0] + ([sep_w] * (ncols-1)) cell_ws = np.cumsum(np.column_stack([sep_widths, cell_widths]).flat) fig_tops, fig_bottoms = (top - cell_hs).reshape((-1, 2)).T fig_lefts, fig_rights = (left + cell_ws).reshape((-1, 2)).T return fig_bottoms, fig_tops, fig_lefts, fig_rights
@staticmethod def _check_gridspec_exists(figure, nrows, ncols): """ Check if the figure already has a gridspec with these dimensions, or create a new one """ for ax in figure.get_axes(): if hasattr(ax, 'get_subplotspec'): gs = ax.get_subplotspec().get_gridspec() if hasattr(gs, 'get_topmost_subplotspec'): # This is needed for colorbar gridspec layouts. # This is probably OK because this whole logic tree # is for when the user is doing simple things with the # add_subplot command. For complicated layouts # like subgridspecs the proper gridspec is passed in... gs = gs.get_topmost_subplotspec().get_gridspec() if gs.get_geometry() == (nrows, ncols): return gs # else gridspec not found: return GridSpec(nrows, ncols, figure=figure) def __getitem__(self, key): """Create and return a `.SubplotSpec` instance.""" nrows, ncols = self.get_geometry() def _normalize(key, size, axis): # Includes last index. orig_key = key if isinstance(key, slice): start, stop, _ = key.indices(size) if stop > start: return start, stop - 1 raise IndexError("GridSpec slice would result in no space " "allocated for subplot") else: if key < 0: key = key + size if 0 <= key < size: return key, key elif axis is not None: raise IndexError(f"index {orig_key} is out of bounds for " f"axis {axis} with size {size}") else: # flat index raise IndexError(f"index {orig_key} is out of bounds for " f"GridSpec with size {size}") if isinstance(key, tuple): try: k1, k2 = key except ValueError as err: raise ValueError("Unrecognized subplot spec") from err num1, num2 = np.ravel_multi_index( [_normalize(k1, nrows, 0), _normalize(k2, ncols, 1)], (nrows, ncols)) else: # Single key num1, num2 = _normalize(key, nrows * ncols, None) return SubplotSpec(self, num1, num2)
[docs] def subplots(self, *, sharex=False, sharey=False, squeeze=True, subplot_kw=None): """ Add all subplots specified by this `GridSpec` to its parent figure. See `.Figure.subplots` for detailed documentation. """ figure = self.figure if figure is None: raise ValueError("GridSpec.subplots() only works for GridSpecs " "created with a parent figure") if isinstance(sharex, bool): sharex = "all" if sharex else "none" if isinstance(sharey, bool): sharey = "all" if sharey else "none" # This check was added because it is very easy to type # `subplots(1, 2, 1)` when `subplot(1, 2, 1)` was intended. # In most cases, no error will ever occur, but mysterious behavior # will result because what was intended to be the subplot index is # instead treated as a bool for sharex. This check should go away # once sharex becomes kwonly. if isinstance(sharex, Integral): _api.warn_external( "sharex argument to subplots() was an integer. Did you " "intend to use subplot() (without 's')?") _api.check_in_list(["all", "row", "col", "none"], sharex=sharex, sharey=sharey) if subplot_kw is None: subplot_kw = {} # don't mutate kwargs passed by user... subplot_kw = subplot_kw.copy() # Create array to hold all axes. axarr = np.empty((self._nrows, self._ncols), dtype=object) for row in range(self._nrows): for col in range(self._ncols): shared_with = {"none": None, "all": axarr[0, 0], "row": axarr[row, 0], "col": axarr[0, col]} subplot_kw["sharex"] = shared_with[sharex] subplot_kw["sharey"] = shared_with[sharey] axarr[row, col] = figure.add_subplot( self[row, col], **subplot_kw) # turn off redundant tick labeling if all(ax.name == "rectilinear" for ax in axarr.flat): if sharex in ["col", "all"]: for ax in axarr.flat: ax._label_outer_xaxis() if sharey in ["row", "all"]: for ax in axarr.flat: ax._label_outer_yaxis() if squeeze: # Discarding unneeded dimensions that equal 1. If we only have one # subplot, just return it instead of a 1-element array. return axarr.item() if axarr.size == 1 else axarr.squeeze() else: # Returned axis array will be always 2-d, even if nrows=ncols=1. return axarr
[docs]class GridSpec(GridSpecBase): """ A grid layout to place subplots within a figure. The location of the grid cells is determined in a similar way to `~.figure.SubplotParams` using *left*, *right*, *top*, *bottom*, *wspace* and *hspace*. """ def __init__(self, nrows, ncols, figure=None, left=None, bottom=None, right=None, top=None, wspace=None, hspace=None, width_ratios=None, height_ratios=None): """ Parameters ---------- nrows, ncols : int The number of rows and columns of the grid. figure : `~.figure.Figure`, optional Only used for constrained layout to create a proper layoutgrid. left, right, top, bottom : float, optional Extent of the subplots as a fraction of figure width or height. Left cannot be larger than right, and bottom cannot be larger than top. If not given, the values will be inferred from a figure or rcParams at draw time. See also `GridSpec.get_subplot_params`. wspace : float, optional The amount of width reserved for space between subplots, expressed as a fraction of the average axis width. If not given, the values will be inferred from a figure or rcParams when necessary. See also `GridSpec.get_subplot_params`. hspace : float, optional The amount of height reserved for space between subplots, expressed as a fraction of the average axis height. If not given, the values will be inferred from a figure or rcParams when necessary. See also `GridSpec.get_subplot_params`. width_ratios : array-like of length *ncols*, optional Defines the relative widths of the columns. Each column gets a relative width of ``width_ratios[i] / sum(width_ratios)``. If not given, all columns will have the same width. height_ratios : array-like of length *nrows*, optional Defines the relative heights of the rows. Each column gets a relative height of ``height_ratios[i] / sum(height_ratios)``. If not given, all rows will have the same height. """ self.left = left self.bottom = bottom self.right = right self.top = top self.wspace = wspace self.hspace = hspace self.figure = figure super().__init__(nrows, ncols, width_ratios=width_ratios, height_ratios=height_ratios) # set up layoutgrid for constrained_layout: self._layoutgrid = None if self.figure is None or not self.figure.get_constrained_layout(): self._layoutgrid = None else: self._toplayoutbox = self.figure._layoutgrid self._layoutgrid = layoutgrid.LayoutGrid( parent=self.figure._layoutgrid, parent_inner=True, name=(self.figure._layoutgrid.name + '.gridspec' + layoutgrid.seq_id()), ncols=ncols, nrows=nrows, width_ratios=width_ratios, height_ratios=height_ratios) _AllowedKeys = ["left", "bottom", "right", "top", "wspace", "hspace"] def __getstate__(self): return {**self.__dict__, "_layoutgrid": None}
[docs] def update(self, **kwargs): """ Update the subplot parameters of the grid. Parameters that are not explicitly given are not changed. Setting a parameter to *None* resets it to :rc:`figure.subplot.*`. Parameters ---------- left, right, top, bottom : float or None, optional Extent of the subplots as a fraction of figure width or height. wspace, hspace : float, optional Spacing between the subplots as a fraction of the average subplot width / height. """ for k, v in kwargs.items(): if k in self._AllowedKeys: setattr(self, k, v) else: raise AttributeError(f"{k} is an unknown keyword") for figmanager in _pylab_helpers.Gcf.figs.values(): for ax in figmanager.canvas.figure.axes: if isinstance(ax, mpl.axes.SubplotBase): ss = ax.get_subplotspec().get_topmost_subplotspec() if ss.get_gridspec() == self: ax._set_position( ax.get_subplotspec().get_position(ax.figure))
[docs] def get_subplot_params(self, figure=None): """ Return the `.SubplotParams` for the GridSpec. In order of precedence the values are taken from - non-*None* attributes of the GridSpec - the provided *figure* - :rc:`figure.subplot.*` """ if figure is None: kw = {k: rcParams["figure.subplot."+k] for k in self._AllowedKeys} subplotpars = mpl.figure.SubplotParams(**kw) else: subplotpars = copy.copy(figure.subplotpars) subplotpars.update(**{k: getattr(self, k) for k in self._AllowedKeys}) return subplotpars
[docs] def locally_modified_subplot_params(self): """ Return a list of the names of the subplot parameters explicitly set in the GridSpec. This is a subset of the attributes of `.SubplotParams`. """ return [k for k in self._AllowedKeys if getattr(self, k)]
[docs] def tight_layout(self, figure, renderer=None, pad=1.08, h_pad=None, w_pad=None, rect=None): """ Adjust subplot parameters to give specified padding. Parameters ---------- pad : float Padding between the figure edge and the edges of subplots, as a fraction of the font-size. h_pad, w_pad : float, optional Padding (height/width) between edges of adjacent subplots. Defaults to *pad*. rect : tuple of 4 floats, default: (0, 0, 1, 1), i.e. the whole figure (left, bottom, right, top) rectangle in normalized figure coordinates that the whole subplots area (including labels) will fit into. """ subplotspec_list = tight_layout.get_subplotspec_list( figure.axes, grid_spec=self) if None in subplotspec_list: _api.warn_external("This figure includes Axes that are not " "compatible with tight_layout, so results " "might be incorrect.") if renderer is None: renderer = tight_layout.get_renderer(figure) kwargs = tight_layout.get_tight_layout_figure( figure, figure.axes, subplotspec_list, renderer, pad=pad, h_pad=h_pad, w_pad=w_pad, rect=rect) if kwargs: self.update(**kwargs)
[docs]class GridSpecFromSubplotSpec(GridSpecBase): """ GridSpec whose subplot layout parameters are inherited from the location specified by a given SubplotSpec. """ def __init__(self, nrows, ncols, subplot_spec, wspace=None, hspace=None, height_ratios=None, width_ratios=None): """ The number of rows and number of columns of the grid need to be set. An instance of SubplotSpec is also needed to be set from which the layout parameters will be inherited. The wspace and hspace of the layout can be optionally specified or the default values (from the figure or rcParams) will be used. """ self._wspace = wspace self._hspace = hspace self._subplot_spec = subplot_spec self.figure = self._subplot_spec.get_gridspec().figure super().__init__(nrows, ncols, width_ratios=width_ratios, height_ratios=height_ratios) # do the layoutgrids for constrained_layout: subspeclb = subplot_spec.get_gridspec()._layoutgrid if subspeclb is None: self._layoutgrid = None else: # this _toplayoutbox is a container that spans the cols and # rows in the parent gridspec. Not yet implemented, # but we do this so that it is possible to have subgridspec # level artists. self._toplayoutgrid = layoutgrid.LayoutGrid( parent=subspeclb, name=subspeclb.name + '.top' + layoutgrid.seq_id(), nrows=1, ncols=1, parent_pos=(subplot_spec.rowspan, subplot_spec.colspan)) self._layoutgrid = layoutgrid.LayoutGrid( parent=self._toplayoutgrid, name=(self._toplayoutgrid.name + '.gridspec' + layoutgrid.seq_id()), nrows=nrows, ncols=ncols, width_ratios=width_ratios, height_ratios=height_ratios)
[docs] def get_subplot_params(self, figure=None): """Return a dictionary of subplot layout parameters.""" hspace = (self._hspace if self._hspace is not None else figure.subplotpars.hspace if figure is not None else rcParams["figure.subplot.hspace"]) wspace = (self._wspace if self._wspace is not None else figure.subplotpars.wspace if figure is not None else rcParams["figure.subplot.wspace"]) figbox = self._subplot_spec.get_position(figure) left, bottom, right, top = figbox.extents return mpl.figure.SubplotParams(left=left, right=right, bottom=bottom, top=top, wspace=wspace, hspace=hspace)
[docs] def get_topmost_subplotspec(self): """ Return the topmost `.SubplotSpec` instance associated with the subplot. """ return self._subplot_spec.get_topmost_subplotspec()
[docs]class SubplotSpec: """ Specifies the location of a subplot in a `GridSpec`. .. note:: Likely, you'll never instantiate a `SubplotSpec` yourself. Instead you will typically obtain one from a `GridSpec` using item-access. Parameters ---------- gridspec : `~matplotlib.gridspec.GridSpec` The GridSpec, which the subplot is referencing. num1, num2 : int The subplot will occupy the num1-th cell of the given gridspec. If num2 is provided, the subplot will span between num1-th cell and num2-th cell *inclusive*. The index starts from 0. """ def __init__(self, gridspec, num1, num2=None): self._gridspec = gridspec self.num1 = num1 self.num2 = num2 def __repr__(self): return (f"{self.get_gridspec()}[" f"{self.rowspan.start}:{self.rowspan.stop}, " f"{self.colspan.start}:{self.colspan.stop}]") @staticmethod def _from_subplot_args(figure, args): """ Construct a `.SubplotSpec` from a parent `.Figure` and either - a `.SubplotSpec` -- returned as is; - one or three numbers -- a MATLAB-style subplot specifier. """ message = ("Passing non-integers as three-element position " "specification is deprecated since %(since)s and will be " "removed %(removal)s.") if len(args) == 1: arg, = args if isinstance(arg, SubplotSpec): return arg else: if not isinstance(arg, Integral): _api.warn_deprecated("3.3", message=message) arg = str(arg) try: rows, cols, num = map(int, str(arg)) except ValueError: raise ValueError( f"Single argument to subplot must be a three-digit " f"integer, not {arg}") from None i = j = num elif len(args) == 3: rows, cols, num = args if not (isinstance(rows, Integral) and isinstance(cols, Integral)): _api.warn_deprecated("3.3", message=message) rows, cols = map(int, [rows, cols]) gs = GridSpec(rows, cols, figure=figure) if isinstance(num, tuple) and len(num) == 2: if not all(isinstance(n, Integral) for n in num): _api.warn_deprecated("3.3", message=message) i, j = map(int, num) else: i, j = num else: if not isinstance(num, Integral): _api.warn_deprecated("3.3", message=message) num = int(num) if num < 1 or num > rows*cols: raise ValueError( f"num must be 1 <= num <= {rows*cols}, not {num}") i = j = num else: raise TypeError(f"subplot() takes 1 or 3 positional arguments but " f"{len(args)} were given") gs = GridSpec._check_gridspec_exists(figure, rows, cols) if gs is None: gs = GridSpec(rows, cols, figure=figure) return gs[i-1:j] # num2 is a property only to handle the case where it is None and someone # mutates num1. @property def num2(self): return self.num1 if self._num2 is None else self._num2 @num2.setter def num2(self, value): self._num2 = value def __getstate__(self): return {**self.__dict__}
[docs] def get_gridspec(self): return self._gridspec
[docs] def get_geometry(self): """ Return the subplot geometry as tuple ``(n_rows, n_cols, start, stop)``. The indices *start* and *stop* define the range of the subplot within the `GridSpec`. *stop* is inclusive (i.e. for a single cell ``start == stop``). """ rows, cols = self.get_gridspec().get_geometry() return rows, cols, self.num1, self.num2
[docs] @_api.deprecated("3.3", alternative="rowspan, colspan") def get_rows_columns(self): """ Return the subplot row and column numbers as a tuple ``(n_rows, n_cols, row_start, row_stop, col_start, col_stop)``. """ gridspec = self.get_gridspec() nrows, ncols = gridspec.get_geometry() row_start, col_start = divmod(self.num1, ncols) row_stop, col_stop = divmod(self.num2, ncols) return nrows, ncols, row_start, row_stop, col_start, col_stop
@property def rowspan(self): """The rows spanned by this subplot, as a `range` object.""" ncols = self.get_gridspec().ncols return range(self.num1 // ncols, self.num2 // ncols + 1) @property def colspan(self): """The columns spanned by this subplot, as a `range` object.""" ncols = self.get_gridspec().ncols # We explicitly support num2 referring to a column on num1's *left*, so # we must sort the column indices here so that the range makes sense. c1, c2 = sorted([self.num1 % ncols, self.num2 % ncols]) return range(c1, c2 + 1)
[docs] def is_first_row(self): return self.rowspan.start == 0
[docs] def is_last_row(self): return self.rowspan.stop == self.get_gridspec().nrows
[docs] def is_first_col(self): return self.colspan.start == 0
[docs] def is_last_col(self): return self.colspan.stop == self.get_gridspec().ncols
[docs] @_api.delete_parameter("3.4", "return_all") def get_position(self, figure, return_all=False): """ Update the subplot position from ``figure.subplotpars``. """ gridspec = self.get_gridspec() nrows, ncols = gridspec.get_geometry() rows, cols = np.unravel_index([self.num1, self.num2], (nrows, ncols)) fig_bottoms, fig_tops, fig_lefts, fig_rights = \ gridspec.get_grid_positions(figure) fig_bottom = fig_bottoms[rows].min() fig_top = fig_tops[rows].max() fig_left = fig_lefts[cols].min() fig_right = fig_rights[cols].max() figbox = Bbox.from_extents(fig_left, fig_bottom, fig_right, fig_top) if return_all: return figbox, rows[0], cols[0], nrows, ncols else: return figbox
[docs] def get_topmost_subplotspec(self): """ Return the topmost `SubplotSpec` instance associated with the subplot. """ gridspec = self.get_gridspec() if hasattr(gridspec, "get_topmost_subplotspec"): return gridspec.get_topmost_subplotspec() else: return self
def __eq__(self, other): """ Two SubplotSpecs are considered equal if they refer to the same position(s) in the same `GridSpec`. """ # other may not even have the attributes we are checking. return ((self._gridspec, self.num1, self.num2) == (getattr(other, "_gridspec", object()), getattr(other, "num1", object()), getattr(other, "num2", object()))) def __hash__(self): return hash((self._gridspec, self.num1, self.num2))
[docs] def subgridspec(self, nrows, ncols, **kwargs): """ Create a GridSpec within this subplot. The created `.GridSpecFromSubplotSpec` will have this `SubplotSpec` as a parent. Parameters ---------- nrows : int Number of rows in grid. ncols : int Number or columns in grid. Returns ------- `.GridSpecFromSubplotSpec` Other Parameters ---------------- **kwargs All other parameters are passed to `.GridSpecFromSubplotSpec`. See Also -------- matplotlib.pyplot.subplots Examples -------- Adding three subplots in the space occupied by a single subplot:: fig = plt.figure() gs0 = fig.add_gridspec(3, 1) ax1 = fig.add_subplot(gs0[0]) ax2 = fig.add_subplot(gs0[1]) gssub = gs0[2].subgridspec(1, 3) for i in range(3): fig.add_subplot(gssub[0, i]) """ return GridSpecFromSubplotSpec(nrows, ncols, self, **kwargs)