""" The legend module defines the Legend class, which is responsible for drawing legends associated with Axes and/or figures. .. important:: It is unlikely that you would ever create a Legend instance manually. Most users would normally create a legend via the `~.Axes.legend` function. For more details on legends there is also a :ref:`legend guide `. The `Legend` class is a container of legend handles and legend texts. The legend handler map specifies how to create legend handles from artists (lines, patches, etc.) in the Axes or figures. Default legend handlers are defined in the :mod:`~matplotlib.legend_handler` module. While not all artist types are covered by the default legend handlers, custom legend handlers can be defined to support arbitrary objects. See the :ref`` for more information. """ import itertools import logging import numbers import time import numpy as np import matplotlib as mpl from matplotlib import _api, _docstring, cbook, colors, offsetbox from matplotlib.artist import Artist, allow_rasterization from matplotlib.cbook import silent_list from matplotlib.font_manager import FontProperties from matplotlib.lines import Line2D from matplotlib.patches import (Patch, Rectangle, Shadow, FancyBboxPatch, StepPatch) from matplotlib.collections import ( Collection, CircleCollection, LineCollection, PathCollection, PolyCollection, RegularPolyCollection) from matplotlib.text import Text from matplotlib.transforms import Bbox, BboxBase, TransformedBbox from matplotlib.transforms import BboxTransformTo, BboxTransformFrom from matplotlib.offsetbox import ( AnchoredOffsetbox, DraggableOffsetBox, HPacker, VPacker, DrawingArea, TextArea, ) from matplotlib.container import ErrorbarContainer, BarContainer, StemContainer from . import legend_handler class DraggableLegend(DraggableOffsetBox): def __init__(self, legend, use_blit=False, update="loc"): """ Wrapper around a `.Legend` to support mouse dragging. Parameters ---------- legend : `.Legend` The `.Legend` instance to wrap. use_blit : bool, optional Use blitting for faster image composition. For details see :ref:`func-animation`. update : {'loc', 'bbox'}, optional If "loc", update the *loc* parameter of the legend upon finalizing. If "bbox", update the *bbox_to_anchor* parameter. """ self.legend = legend _api.check_in_list(["loc", "bbox"], update=update) self._update = update super().__init__(legend, legend._legend_box, use_blit=use_blit) def finalize_offset(self): if self._update == "loc": self._update_loc(self.get_loc_in_canvas()) elif self._update == "bbox": self._update_bbox_to_anchor(self.get_loc_in_canvas()) def _update_loc(self, loc_in_canvas): bbox = self.legend.get_bbox_to_anchor() # if bbox has zero width or height, the transformation is # ill-defined. Fall back to the default bbox_to_anchor. if bbox.width == 0 or bbox.height == 0: self.legend.set_bbox_to_anchor(None) bbox = self.legend.get_bbox_to_anchor() _bbox_transform = BboxTransformFrom(bbox) self.legend._loc = tuple(_bbox_transform.transform(loc_in_canvas)) def _update_bbox_to_anchor(self, loc_in_canvas): loc_in_bbox = self.legend.axes.transAxes.transform(loc_in_canvas) self.legend.set_bbox_to_anchor(loc_in_bbox) _legend_kw_doc_base = """ bbox_to_anchor : `.BboxBase`, 2-tuple, or 4-tuple of floats Box that is used to position the legend in conjunction with *loc*. Defaults to ``axes.bbox`` (if called as a method to `.Axes.legend`) or ``figure.bbox`` (if ``figure.legend``). This argument allows arbitrary placement of the legend. Bbox coordinates are interpreted in the coordinate system given by *bbox_transform*, with the default transform Axes or Figure coordinates, depending on which ``legend`` is called. If a 4-tuple or `.BboxBase` is given, then it specifies the bbox ``(x, y, width, height)`` that the legend is placed in. To put the legend in the best location in the bottom right quadrant of the Axes (or figure):: loc='best', bbox_to_anchor=(0.5, 0., 0.5, 0.5) A 2-tuple ``(x, y)`` places the corner of the legend specified by *loc* at x, y. For example, to put the legend's upper right-hand corner in the center of the Axes (or figure) the following keywords can be used:: loc='upper right', bbox_to_anchor=(0.5, 0.5) ncols : int, default: 1 The number of columns that the legend has. For backward compatibility, the spelling *ncol* is also supported but it is discouraged. If both are given, *ncols* takes precedence. prop : None or `~matplotlib.font_manager.FontProperties` or dict The font properties of the legend. If None (default), the current :data:`matplotlib.rcParams` will be used. fontsize : int or {'xx-small', 'x-small', 'small', 'medium', 'large', \ 'x-large', 'xx-large'} The font size of the legend. If the value is numeric the size will be the absolute font size in points. String values are relative to the current default font size. This argument is only used if *prop* is not specified. labelcolor : str or list, default: :rc:`legend.labelcolor` The color of the text in the legend. Either a valid color string (for example, 'red'), or a list of color strings. The labelcolor can also be made to match the color of the line or marker using 'linecolor', 'markerfacecolor' (or 'mfc'), or 'markeredgecolor' (or 'mec'). Labelcolor can be set globally using :rc:`legend.labelcolor`. If None, use :rc:`text.color`. numpoints : int, default: :rc:`legend.numpoints` The number of marker points in the legend when creating a legend entry for a `.Line2D` (line). scatterpoints : int, default: :rc:`legend.scatterpoints` The number of marker points in the legend when creating a legend entry for a `.PathCollection` (scatter plot). scatteryoffsets : iterable of floats, default: ``[0.375, 0.5, 0.3125]`` The vertical offset (relative to the font size) for the markers created for a scatter plot legend entry. 0.0 is at the base the legend text, and 1.0 is at the top. To draw all markers at the same height, set to ``[0.5]``. markerscale : float, default: :rc:`legend.markerscale` The relative size of legend markers compared to the originally drawn ones. markerfirst : bool, default: True If *True*, legend marker is placed to the left of the legend label. If *False*, legend marker is placed to the right of the legend label. reverse : bool, default: False If *True*, the legend labels are displayed in reverse order from the input. If *False*, the legend labels are displayed in the same order as the input. .. versionadded:: 3.7 frameon : bool, default: :rc:`legend.frameon` Whether the legend should be drawn on a patch (frame). fancybox : bool, default: :rc:`legend.fancybox` Whether round edges should be enabled around the `.FancyBboxPatch` which makes up the legend's background. shadow : None, bool or dict, default: :rc:`legend.shadow` Whether to draw a shadow behind the legend. The shadow can be configured using `.Patch` keywords. Customization via :rc:`legend.shadow` is currently not supported. framealpha : float, default: :rc:`legend.framealpha` The alpha transparency of the legend's background. If *shadow* is activated and *framealpha* is ``None``, the default value is ignored. facecolor : "inherit" or color, default: :rc:`legend.facecolor` The legend's background color. If ``"inherit"``, use :rc:`axes.facecolor`. edgecolor : "inherit" or color, default: :rc:`legend.edgecolor` The legend's background patch edge color. If ``"inherit"``, use :rc:`axes.edgecolor`. mode : {"expand", None} If *mode* is set to ``"expand"`` the legend will be horizontally expanded to fill the Axes area (or *bbox_to_anchor* if defines the legend's size). bbox_transform : None or `~matplotlib.transforms.Transform` The transform for the bounding box (*bbox_to_anchor*). For a value of ``None`` (default) the Axes' :data:`~matplotlib.axes.Axes.transAxes` transform will be used. title : str or None The legend's title. Default is no title (``None``). title_fontproperties : None or `~matplotlib.font_manager.FontProperties` or dict The font properties of the legend's title. If None (default), the *title_fontsize* argument will be used if present; if *title_fontsize* is also None, the current :rc:`legend.title_fontsize` will be used. title_fontsize : int or {'xx-small', 'x-small', 'small', 'medium', 'large', \ 'x-large', 'xx-large'}, default: :rc:`legend.title_fontsize` The font size of the legend's title. Note: This cannot be combined with *title_fontproperties*. If you want to set the fontsize alongside other font properties, use the *size* parameter in *title_fontproperties*. alignment : {'center', 'left', 'right'}, default: 'center' The alignment of the legend title and the box of entries. The entries are aligned as a single block, so that markers always lined up. borderpad : float, default: :rc:`legend.borderpad` The fractional whitespace inside the legend border, in font-size units. labelspacing : float, default: :rc:`legend.labelspacing` The vertical space between the legend entries, in font-size units. handlelength : float, default: :rc:`legend.handlelength` The length of the legend handles, in font-size units. handleheight : float, default: :rc:`legend.handleheight` The height of the legend handles, in font-size units. handletextpad : float, default: :rc:`legend.handletextpad` The pad between the legend handle and text, in font-size units. borderaxespad : float, default: :rc:`legend.borderaxespad` The pad between the Axes and legend border, in font-size units. columnspacing : float, default: :rc:`legend.columnspacing` The spacing between columns, in font-size units. handler_map : dict or None The custom dictionary mapping instances or types to a legend handler. This *handler_map* updates the default handler map found at `matplotlib.legend.Legend.get_legend_handler_map`. draggable : bool, default: False Whether the legend can be dragged with the mouse. """ _loc_doc_base = """ loc : str or pair of floats, default: {default} The location of the legend. The strings ``'upper left'``, ``'upper right'``, ``'lower left'``, ``'lower right'`` place the legend at the corresponding corner of the {parent}. The strings ``'upper center'``, ``'lower center'``, ``'center left'``, ``'center right'`` place the legend at the center of the corresponding edge of the {parent}. The string ``'center'`` places the legend at the center of the {parent}. {best} The location can also be a 2-tuple giving the coordinates of the lower-left corner of the legend in {parent} coordinates (in which case *bbox_to_anchor* will be ignored). For back-compatibility, ``'center right'`` (but no other location) can also be spelled ``'right'``, and each "string" location can also be given as a numeric value: ================== ============= Location String Location Code ================== ============= 'best' (Axes only) 0 'upper right' 1 'upper left' 2 'lower left' 3 'lower right' 4 'right' 5 'center left' 6 'center right' 7 'lower center' 8 'upper center' 9 'center' 10 ================== ============= {outside}""" _loc_doc_best = """ The string ``'best'`` places the legend at the location, among the nine locations defined so far, with the minimum overlap with other drawn artists. This option can be quite slow for plots with large amounts of data; your plotting speed may benefit from providing a specific location. """ _legend_kw_axes_st = ( _loc_doc_base.format(parent='axes', default=':rc:`legend.loc`', best=_loc_doc_best, outside='') + _legend_kw_doc_base) _docstring.interpd.register(_legend_kw_axes=_legend_kw_axes_st) _outside_doc = """ If a figure is using the constrained layout manager, the string codes of the *loc* keyword argument can get better layout behaviour using the prefix 'outside'. There is ambiguity at the corners, so 'outside upper right' will make space for the legend above the rest of the axes in the layout, and 'outside right upper' will make space on the right side of the layout. In addition to the values of *loc* listed above, we have 'outside right upper', 'outside right lower', 'outside left upper', and 'outside left lower'. See :ref:`legend_guide` for more details. """ _legend_kw_figure_st = ( _loc_doc_base.format(parent='figure', default="'upper right'", best='', outside=_outside_doc) + _legend_kw_doc_base) _docstring.interpd.register(_legend_kw_figure=_legend_kw_figure_st) _legend_kw_both_st = ( _loc_doc_base.format(parent='axes/figure', default=":rc:`legend.loc` for Axes, 'upper right' for Figure", best=_loc_doc_best, outside=_outside_doc) + _legend_kw_doc_base) _docstring.interpd.register(_legend_kw_doc=_legend_kw_both_st) _legend_kw_set_loc_st = ( _loc_doc_base.format(parent='axes/figure', default=":rc:`legend.loc` for Axes, 'upper right' for Figure", best=_loc_doc_best, outside=_outside_doc)) _docstring.interpd.register(_legend_kw_set_loc_doc=_legend_kw_set_loc_st) class Legend(Artist): """ Place a legend on the figure/axes. """ # 'best' is only implemented for Axes legends codes = {'best': 0, **AnchoredOffsetbox.codes} zorder = 5 def __str__(self): return "Legend" @_docstring.interpd def __init__( self, parent, handles, labels, *, loc=None, numpoints=None, # number of points in the legend line markerscale=None, # relative size of legend markers vs. original markerfirst=True, # left/right ordering of legend marker and label reverse=False, # reverse ordering of legend marker and label scatterpoints=None, # number of scatter points scatteryoffsets=None, prop=None, # properties for the legend texts fontsize=None, # keyword to set font size directly labelcolor=None, # keyword to set the text color # spacing & pad defined as a fraction of the font-size borderpad=None, # whitespace inside the legend border labelspacing=None, # vertical space between the legend entries handlelength=None, # length of the legend handles handleheight=None, # height of the legend handles handletextpad=None, # pad between the legend handle and text borderaxespad=None, # pad between the Axes and legend border columnspacing=None, # spacing between columns ncols=1, # number of columns mode=None, # horizontal distribution of columns: None or "expand" fancybox=None, # True: fancy box, False: rounded box, None: rcParam shadow=None, title=None, # legend title title_fontsize=None, # legend title font size framealpha=None, # set frame alpha edgecolor=None, # frame patch edgecolor facecolor=None, # frame patch facecolor bbox_to_anchor=None, # bbox to which the legend will be anchored bbox_transform=None, # transform for the bbox frameon=None, # draw frame handler_map=None, title_fontproperties=None, # properties for the legend title alignment="center", # control the alignment within the legend box ncol=1, # synonym for ncols (backward compatibility) draggable=False # whether the legend can be dragged with the mouse ): """ Parameters ---------- parent : `~matplotlib.axes.Axes` or `.Figure` The artist that contains the legend. handles : list of (`.Artist` or tuple of `.Artist`) A list of Artists (lines, patches) to be added to the legend. labels : list of str A list of labels to show next to the artists. The length of handles and labels should be the same. If they are not, they are truncated to the length of the shorter list. Other Parameters ---------------- %(_legend_kw_doc)s Attributes ---------- legend_handles List of `.Artist` objects added as legend entries. .. versionadded:: 3.7 """ # local import only to avoid circularity from matplotlib.axes import Axes from matplotlib.figure import FigureBase super().__init__() if prop is None: self.prop = FontProperties(size=mpl._val_or_rc(fontsize, "legend.fontsize")) else: self.prop = FontProperties._from_any(prop) if isinstance(prop, dict) and "size" not in prop: self.prop.set_size(mpl.rcParams["legend.fontsize"]) self._fontsize = self.prop.get_size_in_points() self.texts = [] self.legend_handles = [] self._legend_title_box = None #: A dictionary with the extra handler mappings for this Legend #: instance. self._custom_handler_map = handler_map self.numpoints = mpl._val_or_rc(numpoints, 'legend.numpoints') self.markerscale = mpl._val_or_rc(markerscale, 'legend.markerscale') self.scatterpoints = mpl._val_or_rc(scatterpoints, 'legend.scatterpoints') self.borderpad = mpl._val_or_rc(borderpad, 'legend.borderpad') self.labelspacing = mpl._val_or_rc(labelspacing, 'legend.labelspacing') self.handlelength = mpl._val_or_rc(handlelength, 'legend.handlelength') self.handleheight = mpl._val_or_rc(handleheight, 'legend.handleheight') self.handletextpad = mpl._val_or_rc(handletextpad, 'legend.handletextpad') self.borderaxespad = mpl._val_or_rc(borderaxespad, 'legend.borderaxespad') self.columnspacing = mpl._val_or_rc(columnspacing, 'legend.columnspacing') self.shadow = mpl._val_or_rc(shadow, 'legend.shadow') if reverse: labels = [*reversed(labels)] handles = [*reversed(handles)] if len(handles) < 2: ncols = 1 self._ncols = ncols if ncols != 1 else ncol if self.numpoints <= 0: raise ValueError("numpoints must be > 0; it was %d" % numpoints) # introduce y-offset for handles of the scatter plot if scatteryoffsets is None: self._scatteryoffsets = np.array([3. / 8., 4. / 8., 2.5 / 8.]) else: self._scatteryoffsets = np.asarray(scatteryoffsets) reps = self.scatterpoints // len(self._scatteryoffsets) + 1 self._scatteryoffsets = np.tile(self._scatteryoffsets, reps)[:self.scatterpoints] # _legend_box is a VPacker instance that contains all # legend items and will be initialized from _init_legend_box() # method. self._legend_box = None if isinstance(parent, Axes): self.isaxes = True self.axes = parent self.set_figure(parent.get_figure(root=False)) elif isinstance(parent, FigureBase): self.isaxes = False self.set_figure(parent) else: raise TypeError( "Legend needs either Axes or FigureBase as parent" ) self.parent = parent self._mode = mode self.set_bbox_to_anchor(bbox_to_anchor, bbox_transform) # Figure out if self.shadow is valid # If shadow was None, rcParams loads False # So it shouldn't be None here self._shadow_props = {'ox': 2, 'oy': -2} # default location offsets if isinstance(self.shadow, dict): self._shadow_props.update(self.shadow) self.shadow = True elif self.shadow in (0, 1, True, False): self.shadow = bool(self.shadow) else: raise ValueError( 'Legend shadow must be a dict or bool, not ' f'{self.shadow!r} of type {type(self.shadow)}.' ) # We use FancyBboxPatch to draw a legend frame. The location # and size of the box will be updated during the drawing time. facecolor = mpl._val_or_rc(facecolor, "legend.facecolor") if facecolor == 'inherit': facecolor = mpl.rcParams["axes.facecolor"] edgecolor = mpl._val_or_rc(edgecolor, "legend.edgecolor") if edgecolor == 'inherit': edgecolor = mpl.rcParams["axes.edgecolor"] fancybox = mpl._val_or_rc(fancybox, "legend.fancybox") self.legendPatch = FancyBboxPatch( xy=(0, 0), width=1, height=1, facecolor=facecolor, edgecolor=edgecolor, # If shadow is used, default to alpha=1 (#8943). alpha=(framealpha if framealpha is not None else 1 if shadow else mpl.rcParams["legend.framealpha"]), # The width and height of the legendPatch will be set (in draw()) # to the length that includes the padding. Thus we set pad=0 here. boxstyle=("round,pad=0,rounding_size=0.2" if fancybox else "square,pad=0"), mutation_scale=self._fontsize, snap=True, visible=mpl._val_or_rc(frameon, "legend.frameon") ) self._set_artist_props(self.legendPatch) _api.check_in_list(["center", "left", "right"], alignment=alignment) self._alignment = alignment # init with null renderer self._init_legend_box(handles, labels, markerfirst) # Set legend location self.set_loc(loc) # figure out title font properties: if title_fontsize is not None and title_fontproperties is not None: raise ValueError( "title_fontsize and title_fontproperties can't be specified " "at the same time. Only use one of them. ") title_prop_fp = FontProperties._from_any(title_fontproperties) if isinstance(title_fontproperties, dict): if "size" not in title_fontproperties: title_fontsize = mpl.rcParams["legend.title_fontsize"] title_prop_fp.set_size(title_fontsize) elif title_fontsize is not None: title_prop_fp.set_size(title_fontsize) elif not isinstance(title_fontproperties, FontProperties): title_fontsize = mpl.rcParams["legend.title_fontsize"] title_prop_fp.set_size(title_fontsize) self.set_title(title, prop=title_prop_fp) self._draggable = None self.set_draggable(state=draggable) # set the text color color_getters = { # getter function depends on line or patch 'linecolor': ['get_color', 'get_facecolor'], 'markerfacecolor': ['get_markerfacecolor', 'get_facecolor'], 'mfc': ['get_markerfacecolor', 'get_facecolor'], 'markeredgecolor': ['get_markeredgecolor', 'get_edgecolor'], 'mec': ['get_markeredgecolor', 'get_edgecolor'], } labelcolor = mpl._val_or_rc(labelcolor, 'legend.labelcolor') if labelcolor is None: labelcolor = mpl.rcParams['text.color'] if isinstance(labelcolor, str) and labelcolor in color_getters: getter_names = color_getters[labelcolor] for handle, text in zip(self.legend_handles, self.texts): try: if handle.get_array() is not None: continue except AttributeError: pass for getter_name in getter_names: try: color = getattr(handle, getter_name)() if isinstance(color, np.ndarray): if ( color.shape[0] == 1 or np.isclose(color, color[0]).all() ): text.set_color(color[0]) else: pass else: text.set_color(color) break except AttributeError: pass elif cbook._str_equal(labelcolor, 'none'): for text in self.texts: text.set_color(labelcolor) elif np.iterable(labelcolor): for text, color in zip(self.texts, itertools.cycle( colors.to_rgba_array(labelcolor))): text.set_color(color) else: raise ValueError(f"Invalid labelcolor: {labelcolor!r}") def _set_artist_props(self, a): """ Set the boilerplate props for artists added to Axes. """ a.set_figure(self.get_figure(root=False)) if self.isaxes: a.axes = self.axes a.set_transform(self.get_transform()) @_docstring.interpd def set_loc(self, loc=None): """ Set the location of the legend. .. versionadded:: 3.8 Parameters ---------- %(_legend_kw_set_loc_doc)s """ loc0 = loc self._loc_used_default = loc is None if loc is None: loc = mpl.rcParams["legend.loc"] if not self.isaxes and loc in [0, 'best']: loc = 'upper right' type_err_message = ("loc must be string, coordinate tuple, or" f" an integer 0-10, not {loc!r}") # handle outside legends: self._outside_loc = None if isinstance(loc, str): if loc.split()[0] == 'outside': # strip outside: loc = loc.split('outside ')[1] # strip "center" at the beginning self._outside_loc = loc.replace('center ', '') # strip first self._outside_loc = self._outside_loc.split()[0] locs = loc.split() if len(locs) > 1 and locs[0] in ('right', 'left'): # locs doesn't accept "left upper", etc, so swap if locs[0] != 'center': locs = locs[::-1] loc = locs[0] + ' ' + locs[1] # check that loc is in acceptable strings loc = _api.check_getitem(self.codes, loc=loc) elif np.iterable(loc): # coerce iterable into tuple loc = tuple(loc) # validate the tuple represents Real coordinates if len(loc) != 2 or not all(isinstance(e, numbers.Real) for e in loc): raise ValueError(type_err_message) elif isinstance(loc, int): # validate the integer represents a string numeric value if loc < 0 or loc > 10: raise ValueError(type_err_message) else: # all other cases are invalid values of loc raise ValueError(type_err_message) if self.isaxes and self._outside_loc: raise ValueError( f"'outside' option for loc='{loc0}' keyword argument only " "works for figure legends") if not self.isaxes and loc == 0: raise ValueError( "Automatic legend placement (loc='best') not implemented for " "figure legend") tmp = self._loc_used_default self._set_loc(loc) self._loc_used_default = tmp # ignore changes done by _set_loc def _set_loc(self, loc): # find_offset function will be provided to _legend_box and # _legend_box will draw itself at the location of the return # value of the find_offset. self._loc_used_default = False self._loc_real = loc self.stale = True self._legend_box.set_offset(self._findoffset) def set_ncols(self, ncols): """Set the number of columns.""" self._ncols = ncols def _get_loc(self): return self._loc_real _loc = property(_get_loc, _set_loc) def _findoffset(self, width, height, xdescent, ydescent, renderer): """Helper function to locate the legend.""" if self._loc == 0: # "best". x, y = self._find_best_position(width, height, renderer) elif self._loc in Legend.codes.values(): # Fixed location. bbox = Bbox.from_bounds(0, 0, width, height) x, y = self._get_anchored_bbox(self._loc, bbox, self.get_bbox_to_anchor(), renderer) else: # Axes or figure coordinates. fx, fy = self._loc bbox = self.get_bbox_to_anchor() x, y = bbox.x0 + bbox.width * fx, bbox.y0 + bbox.height * fy return x + xdescent, y + ydescent @allow_rasterization def draw(self, renderer): # docstring inherited if not self.get_visible(): return renderer.open_group('legend', gid=self.get_gid()) fontsize = renderer.points_to_pixels(self._fontsize) # if mode == fill, set the width of the legend_box to the # width of the parent (minus pads) if self._mode in ["expand"]: pad = 2 * (self.borderaxespad + self.borderpad) * fontsize self._legend_box.set_width(self.get_bbox_to_anchor().width - pad) # update the location and size of the legend. This needs to # be done in any case to clip the figure right. bbox = self._legend_box.get_window_extent(renderer) self.legendPatch.set_bounds(bbox.bounds) self.legendPatch.set_mutation_scale(fontsize) # self.shadow is validated in __init__ # So by here it is a bool and self._shadow_props contains any configs if self.shadow: Shadow(self.legendPatch, **self._shadow_props).draw(renderer) self.legendPatch.draw(renderer) self._legend_box.draw(renderer) renderer.close_group('legend') self.stale = False # _default_handler_map defines the default mapping between plot # elements and the legend handlers. _default_handler_map = { StemContainer: legend_handler.HandlerStem(), ErrorbarContainer: legend_handler.HandlerErrorbar(), Line2D: legend_handler.HandlerLine2D(), Patch: legend_handler.HandlerPatch(), StepPatch: legend_handler.HandlerStepPatch(), LineCollection: legend_handler.HandlerLineCollection(), RegularPolyCollection: legend_handler.HandlerRegularPolyCollection(), CircleCollection: legend_handler.HandlerCircleCollection(), BarContainer: legend_handler.HandlerPatch( update_func=legend_handler.update_from_first_child), tuple: legend_handler.HandlerTuple(), PathCollection: legend_handler.HandlerPathCollection(), PolyCollection: legend_handler.HandlerPolyCollection() } # (get|set|update)_default_handler_maps are public interfaces to # modify the default handler map. @classmethod def get_default_handler_map(cls): """Return the global default handler map, shared by all legends.""" return cls._default_handler_map @classmethod def set_default_handler_map(cls, handler_map): """Set the global default handler map, shared by all legends.""" cls._default_handler_map = handler_map @classmethod def update_default_handler_map(cls, handler_map): """Update the global default handler map, shared by all legends.""" cls._default_handler_map.update(handler_map) def get_legend_handler_map(self): """Return this legend instance's handler map.""" default_handler_map = self.get_default_handler_map() return ({**default_handler_map, **self._custom_handler_map} if self._custom_handler_map else default_handler_map) @staticmethod def get_legend_handler(legend_handler_map, orig_handle): """ Return a legend handler from *legend_handler_map* that corresponds to *orig_handler*. *legend_handler_map* should be a dictionary object (that is returned by the get_legend_handler_map method). It first checks if the *orig_handle* itself is a key in the *legend_handler_map* and return the associated value. Otherwise, it checks for each of the classes in its method-resolution-order. If no matching key is found, it returns ``None``. """ try: return legend_handler_map[orig_handle] except (TypeError, KeyError): # TypeError if unhashable. pass for handle_type in type(orig_handle).mro(): try: return legend_handler_map[handle_type] except KeyError: pass return None def _init_legend_box(self, handles, labels, markerfirst=True): """ Initialize the legend_box. The legend_box is an instance of the OffsetBox, which is packed with legend handles and texts. Once packed, their location is calculated during the drawing time. """ fontsize = self._fontsize # legend_box is a HPacker, horizontally packed with columns. # Each column is a VPacker, vertically packed with legend items. # Each legend item is a HPacker packed with: # - handlebox: a DrawingArea which contains the legend handle. # - labelbox: a TextArea which contains the legend text. text_list = [] # the list of text instances handle_list = [] # the list of handle instances handles_and_labels = [] # The approximate height and descent of text. These values are # only used for plotting the legend handle. descent = 0.35 * fontsize * (self.handleheight - 0.7) # heuristic. height = fontsize * self.handleheight - descent # each handle needs to be drawn inside a box of (x, y, w, h) = # (0, -descent, width, height). And their coordinates should # be given in the display coordinates. # The transformation of each handle will be automatically set # to self.get_transform(). If the artist does not use its # default transform (e.g., Collections), you need to # manually set their transform to the self.get_transform(). legend_handler_map = self.get_legend_handler_map() for orig_handle, label in zip(handles, labels): handler = self.get_legend_handler(legend_handler_map, orig_handle) if handler is None: _api.warn_external( "Legend does not support handles for " f"{type(orig_handle).__name__} " "instances.\nA proxy artist may be used " "instead.\nSee: https://matplotlib.org/" "stable/users/explain/axes/legend_guide.html" "#controlling-the-legend-entries") # No handle for this artist, so we just defer to None. handle_list.append(None) else: textbox = TextArea(label, multilinebaseline=True, textprops=dict( verticalalignment='baseline', horizontalalignment='left', fontproperties=self.prop)) handlebox = DrawingArea(width=self.handlelength * fontsize, height=height, xdescent=0., ydescent=descent) text_list.append(textbox._text) # Create the artist for the legend which represents the # original artist/handle. handle_list.append(handler.legend_artist(self, orig_handle, fontsize, handlebox)) handles_and_labels.append((handlebox, textbox)) columnbox = [] # array_split splits n handles_and_labels into ncols columns, with the # first n%ncols columns having an extra entry. filter(len, ...) # handles the case where n < ncols: the last ncols-n columns are empty # and get filtered out. for handles_and_labels_column in filter( len, np.array_split(handles_and_labels, self._ncols)): # pack handlebox and labelbox into itembox itemboxes = [HPacker(pad=0, sep=self.handletextpad * fontsize, children=[h, t] if markerfirst else [t, h], align="baseline") for h, t in handles_and_labels_column] # pack columnbox alignment = "baseline" if markerfirst else "right" columnbox.append(VPacker(pad=0, sep=self.labelspacing * fontsize, align=alignment, children=itemboxes)) mode = "expand" if self._mode == "expand" else "fixed" sep = self.columnspacing * fontsize self._legend_handle_box = HPacker(pad=0, sep=sep, align="baseline", mode=mode, children=columnbox) self._legend_title_box = TextArea("") self._legend_box = VPacker(pad=self.borderpad * fontsize, sep=self.labelspacing * fontsize, align=self._alignment, children=[self._legend_title_box, self._legend_handle_box]) self._legend_box.set_figure(self.get_figure(root=False)) self._legend_box.axes = self.axes self.texts = text_list self.legend_handles = handle_list def _auto_legend_data(self, renderer): """ Return display coordinates for hit testing for "best" positioning. Returns ------- bboxes List of bounding boxes of all patches. lines List of `.Path` corresponding to each line. offsets List of (x, y) offsets of all collection. """ assert self.isaxes # always holds, as this is only called internally bboxes = [] lines = [] offsets = [] for artist in self.parent._children: if isinstance(artist, Line2D): lines.append( artist.get_transform().transform_path(artist.get_path())) elif isinstance(artist, Rectangle): bboxes.append( artist.get_bbox().transformed(artist.get_data_transform())) elif isinstance(artist, Patch): lines.append( artist.get_transform().transform_path(artist.get_path())) elif isinstance(artist, PolyCollection): lines.extend(artist.get_transform().transform_path(path) for path in artist.get_paths()) elif isinstance(artist, Collection): transform, transOffset, hoffsets, _ = artist._prepare_points() if len(hoffsets): offsets.extend(transOffset.transform(hoffsets)) elif isinstance(artist, Text): bboxes.append(artist.get_window_extent(renderer)) return bboxes, lines, offsets def get_children(self): # docstring inherited return [self._legend_box, self.get_frame()] def get_frame(self): """Return the `~.patches.Rectangle` used to frame the legend.""" return self.legendPatch def get_lines(self): r"""Return the list of `~.lines.Line2D`\s in the legend.""" return [h for h in self.legend_handles if isinstance(h, Line2D)] def get_patches(self): r"""Return the list of `~.patches.Patch`\s in the legend.""" return silent_list('Patch', [h for h in self.legend_handles if isinstance(h, Patch)]) def get_texts(self): r"""Return the list of `~.text.Text`\s in the legend.""" return silent_list('Text', self.texts) def set_alignment(self, alignment): """ Set the alignment of the legend title and the box of entries. The entries are aligned as a single block, so that markers always lined up. Parameters ---------- alignment : {'center', 'left', 'right'}. """ _api.check_in_list(["center", "left", "right"], alignment=alignment) self._alignment = alignment self._legend_box.align = alignment def get_alignment(self): """Get the alignment value of the legend box""" return self._legend_box.align def set_title(self, title, prop=None): """ Set legend title and title style. Parameters ---------- title : str The legend title. prop : `.font_manager.FontProperties` or `str` or `pathlib.Path` The font properties of the legend title. If a `str`, it is interpreted as a fontconfig pattern parsed by `.FontProperties`. If a `pathlib.Path`, it is interpreted as the absolute path to a font file. """ self._legend_title_box._text.set_text(title) if title: self._legend_title_box._text.set_visible(True) self._legend_title_box.set_visible(True) else: self._legend_title_box._text.set_visible(False) self._legend_title_box.set_visible(False) if prop is not None: self._legend_title_box._text.set_fontproperties(prop) self.stale = True def get_title(self): """Return the `.Text` instance for the legend title.""" return self._legend_title_box._text def get_window_extent(self, renderer=None): # docstring inherited if renderer is None: renderer = self.get_figure(root=True)._get_renderer() return self._legend_box.get_window_extent(renderer=renderer) def get_tightbbox(self, renderer=None): # docstring inherited return self._legend_box.get_window_extent(renderer) def get_frame_on(self): """Get whether the legend box patch is drawn.""" return self.legendPatch.get_visible() def set_frame_on(self, b): """ Set whether the legend box patch is drawn. Parameters ---------- b : bool """ self.legendPatch.set_visible(b) self.stale = True draw_frame = set_frame_on # Backcompat alias. def get_bbox_to_anchor(self): """Return the bbox that the legend will be anchored to.""" if self._bbox_to_anchor is None: return self.parent.bbox else: return self._bbox_to_anchor def set_bbox_to_anchor(self, bbox, transform=None): """ Set the bbox that the legend will be anchored to. Parameters ---------- bbox : `~matplotlib.transforms.BboxBase` or tuple The bounding box can be specified in the following ways: - A `.BboxBase` instance - A tuple of ``(left, bottom, width, height)`` in the given transform (normalized axes coordinate if None) - A tuple of ``(left, bottom)`` where the width and height will be assumed to be zero. - *None*, to remove the bbox anchoring, and use the parent bbox. transform : `~matplotlib.transforms.Transform`, optional A transform to apply to the bounding box. If not specified, this will use a transform to the bounding box of the parent. """ if bbox is None: self._bbox_to_anchor = None return elif isinstance(bbox, BboxBase): self._bbox_to_anchor = bbox else: try: l = len(bbox) except TypeError as err: raise ValueError(f"Invalid bbox: {bbox}") from err if l == 2: bbox = [bbox[0], bbox[1], 0, 0] self._bbox_to_anchor = Bbox.from_bounds(*bbox) if transform is None: transform = BboxTransformTo(self.parent.bbox) self._bbox_to_anchor = TransformedBbox(self._bbox_to_anchor, transform) self.stale = True def _get_anchored_bbox(self, loc, bbox, parentbbox, renderer): """ Place the *bbox* inside the *parentbbox* according to a given location code. Return the (x, y) coordinate of the bbox. Parameters ---------- loc : int A location code in range(1, 11). This corresponds to the possible values for ``self._loc``, excluding "best". bbox : `~matplotlib.transforms.Bbox` bbox to be placed, in display coordinates. parentbbox : `~matplotlib.transforms.Bbox` A parent box which will contain the bbox, in display coordinates. """ return offsetbox._get_anchored_bbox( loc, bbox, parentbbox, self.borderaxespad * renderer.points_to_pixels(self._fontsize)) def _find_best_position(self, width, height, renderer): """Determine the best location to place the legend.""" assert self.isaxes # always holds, as this is only called internally start_time = time.perf_counter() bboxes, lines, offsets = self._auto_legend_data(renderer) bbox = Bbox.from_bounds(0, 0, width, height) candidates = [] for idx in range(1, len(self.codes)): l, b = self._get_anchored_bbox(idx, bbox, self.get_bbox_to_anchor(), renderer) legendBox = Bbox.from_bounds(l, b, width, height) # XXX TODO: If markers are present, it would be good to take them # into account when checking vertex overlaps in the next line. badness = (sum(legendBox.count_contains(line.vertices) for line in lines) + legendBox.count_contains(offsets) + legendBox.count_overlaps(bboxes) + sum(line.intersects_bbox(legendBox, filled=False) for line in lines)) # Include the index to favor lower codes in case of a tie. candidates.append((badness, idx, (l, b))) if badness == 0: break _, _, (l, b) = min(candidates) if self._loc_used_default and time.perf_counter() - start_time > 1: _api.warn_external( 'Creating legend with loc="best" can be slow with large ' 'amounts of data.') return l, b def contains(self, mouseevent): return self.legendPatch.contains(mouseevent) def set_draggable(self, state, use_blit=False, update='loc'): """ Enable or disable mouse dragging support of the legend. Parameters ---------- state : bool Whether mouse dragging is enabled. use_blit : bool, optional Use blitting for faster image composition. For details see :ref:`func-animation`. update : {'loc', 'bbox'}, optional The legend parameter to be changed when dragged: - 'loc': update the *loc* parameter of the legend - 'bbox': update the *bbox_to_anchor* parameter of the legend Returns ------- `.DraggableLegend` or *None* If *state* is ``True`` this returns the `.DraggableLegend` helper instance. Otherwise this returns *None*. """ if state: if self._draggable is None: self._draggable = DraggableLegend(self, use_blit, update=update) else: if self._draggable is not None: self._draggable.disconnect() self._draggable = None return self._draggable def get_draggable(self): """Return ``True`` if the legend is draggable, ``False`` otherwise.""" return self._draggable is not None # Helper functions to parse legend arguments for both `figure.legend` and # `axes.legend`: def _get_legend_handles(axs, legend_handler_map=None): """Yield artists that can be used as handles in a legend.""" handles_original = [] for ax in axs: handles_original += [ *(a for a in ax._children if isinstance(a, (Line2D, Patch, Collection, Text))), *ax.containers] # support parasite Axes: if hasattr(ax, 'parasites'): for axx in ax.parasites: handles_original += [ *(a for a in axx._children if isinstance(a, (Line2D, Patch, Collection, Text))), *axx.containers] handler_map = {**Legend.get_default_handler_map(), **(legend_handler_map or {})} has_handler = Legend.get_legend_handler for handle in handles_original: label = handle.get_label() if label != '_nolegend_' and has_handler(handler_map, handle): yield handle elif (label and not label.startswith('_') and not has_handler(handler_map, handle)): _api.warn_external( "Legend does not support handles for " f"{type(handle).__name__} " "instances.\nSee: https://matplotlib.org/stable/" "tutorials/intermediate/legend_guide.html" "#implementing-a-custom-legend-handler") continue def _get_legend_handles_labels(axs, legend_handler_map=None): """Return handles and labels for legend.""" handles = [] labels = [] for handle in _get_legend_handles(axs, legend_handler_map): label = handle.get_label() if label and not label.startswith('_'): handles.append(handle) labels.append(label) return handles, labels def _parse_legend_args(axs, *args, handles=None, labels=None, **kwargs): """ Get the handles and labels from the calls to either ``figure.legend`` or ``axes.legend``. The parser is a bit involved because we support:: legend() legend(labels) legend(handles, labels) legend(labels=labels) legend(handles=handles) legend(handles=handles, labels=labels) The behavior for a mixture of positional and keyword handles and labels is undefined and issues a warning; it will be an error in the future. Parameters ---------- axs : list of `.Axes` If handles are not given explicitly, the artists in these Axes are used as handles. *args : tuple Positional parameters passed to ``legend()``. handles The value of the keyword argument ``legend(handles=...)``, or *None* if that keyword argument was not used. labels The value of the keyword argument ``legend(labels=...)``, or *None* if that keyword argument was not used. **kwargs All other keyword arguments passed to ``legend()``. Returns ------- handles : list of (`.Artist` or tuple of `.Artist`) The legend handles. labels : list of str The legend labels. kwargs : dict *kwargs* with keywords handles and labels removed. """ log = logging.getLogger(__name__) handlers = kwargs.get('handler_map') if (handles is not None or labels is not None) and args: _api.warn_deprecated("3.9", message=( "You have mixed positional and keyword arguments, some input may " "be discarded. This is deprecated since %(since)s and will " "become an error in %(removal)s.")) if (hasattr(handles, "__len__") and hasattr(labels, "__len__") and len(handles) != len(labels)): _api.warn_external(f"Mismatched number of handles and labels: " f"len(handles) = {len(handles)} " f"len(labels) = {len(labels)}") # if got both handles and labels as kwargs, make same length if handles and labels: handles, labels = zip(*zip(handles, labels)) elif handles is not None and labels is None: labels = [handle.get_label() for handle in handles] elif labels is not None and handles is None: # Get as many handles as there are labels. handles = [handle for handle, label in zip(_get_legend_handles(axs, handlers), labels)] elif len(args) == 0: # 0 args: automatically detect labels and handles. handles, labels = _get_legend_handles_labels(axs, handlers) if not handles: _api.warn_external( "No artists with labels found to put in legend. Note that " "artists whose label start with an underscore are ignored " "when legend() is called with no argument.") elif len(args) == 1: # 1 arg: user defined labels, automatic handle detection. labels, = args if any(isinstance(l, Artist) for l in labels): raise TypeError("A single argument passed to legend() must be a " "list of labels, but found an Artist in there.") # Get as many handles as there are labels. handles = [handle for handle, label in zip(_get_legend_handles(axs, handlers), labels)] elif len(args) == 2: # 2 args: user defined handles and labels. handles, labels = args[:2] else: raise _api.nargs_error('legend', '0-2', len(args)) return handles, labels, kwargs