matplotlib.legend
¶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
legend()
function. For more details on legends
there is also a legend guide.
The Legend class can be considered as a container of legend handles
and legend texts. Creation of corresponding legend handles from the
plot elements in the axes or figures (e.g., lines, patches, etc.) are
specified by the handler map, which defines the mapping between the
plot elements and the legend handlers to be used (the default legend
handlers are defined in the legend_handler
module).
Note that not all kinds of artist are supported by the legend yet by default
but it is possible to extend the legend handler’s capabilities to
support arbitrary objects. See the legend guide
for more information.
matplotlib.legend.
DraggableLegend
(legend, use_blit=False, update='loc')¶Bases: matplotlib.offsetbox.DraggableOffsetBox
artist_picker
(legend, evt)¶finalize_offset
()¶matplotlib.legend.
Legend
(parent, handles, labels, loc=None, numpoints=None, markerscale=None, markerfirst=True, scatterpoints=None, scatteryoffsets=None, prop=None, fontsize=None, borderpad=None, labelspacing=None, handlelength=None, handleheight=None, handletextpad=None, borderaxespad=None, columnspacing=None, ncol=1, mode=None, fancybox=None, shadow=None, title=None, framealpha=None, edgecolor=None, facecolor=None, bbox_to_anchor=None, bbox_transform=None, frameon=None, handler_map=None)¶Bases: matplotlib.artist.Artist
Place a legend on the axes at location loc. Labels are a sequence of strings and loc can be a string or an integer specifying the legend location
The location codes are:
'best' : 0, (only implemented for axes legends)
'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,
loc can be a tuple of the normalized coordinate values with respect its parent.
parent: the artist that contains the legend
legend
labels: a list of strings to label the legend
Optional keyword arguments:
Keyword | Description |
---|---|
loc | Location code string, or tuple (see below). |
prop | the font property |
fontsize | the font size (used only if prop is not specified) |
markerscale | the relative size of legend markers vs. original |
markerfirst | If True (default), marker is to left of the label. |
numpoints | the number of points in the legend for line |
scatterpoints | the number of points in the legend for scatter plot |
scatteryoffsets | a list of yoffsets for scatter symbols in legend |
frameon | If True, draw the legend on a patch (frame). |
fancybox | If True, draw the frame with a round fancybox. |
shadow | If True, draw a shadow behind legend. |
framealpha | Transparency of the frame. |
edgecolor | Frame edgecolor. |
facecolor | Frame facecolor. |
ncol | number of columns |
borderpad | the fractional whitespace inside the legend border |
labelspacing | the vertical space between the legend entries |
handlelength | the length of the legend handles |
handleheight | the height of the legend handles |
handletextpad | the pad between the legend handle and text |
borderaxespad | the pad between the axes and legend border |
columnspacing | the spacing between columns |
title | the legend title |
bbox_to_anchor | the bbox that the legend will be anchored. |
bbox_transform | the transform for the bbox. transAxes if None. |
The pad and spacing parameters are measured in font-size units. e.g., a fontsize of 10 points and a handlelength=5 implies a handlelength of 50 points. Values from rcParams will be used if None.
Users can specify any arbitrary location for the legend using the
bbox_to_anchor keyword argument. bbox_to_anchor can be an instance
of BboxBase(or its derivatives) or a tuple of 2 or 4 floats.
See set_bbox_to_anchor()
for more detail.
The legend location can be specified by setting loc with a tuple of 2 floats, which is interpreted as the lower-left corner of the legend in the normalized axes coordinate.
codes
= {'lower left': 3, 'right': 5, 'best': 0, 'upper center': 9, 'lower center': 8, 'upper right': 1, 'center left': 6, 'lower right': 4, 'center right': 7, 'center': 10, 'upper left': 2}¶contains
(event)¶draggable
(state=None, use_blit=False, update='loc')¶Set the draggable state – if state is
- None : toggle the current state
- True : turn draggable on
- False : turn draggable off
If draggable is on, you can drag the legend on the canvas with the mouse. The DraggableLegend helper instance is returned if draggable is on.
The update parameter control which parameter of the legend changes when dragged. If update is “loc”, the loc paramter of the legend is changed. If “bbox”, the bbox_to_anchor parameter is changed.
draw
(artist, renderer, *args, **kwargs)¶Draw everything that belongs to the legend
draw_frame
(b)¶b is a boolean. Set draw frame to b
get_bbox_to_anchor
()¶return the bbox that the legend will be anchored
get_children
()¶return a list of child artists
get_default_handler_map
()¶A class method that returns the default handler map.
get_frame
()¶return the Rectangle instance used to frame the legend
get_frame_on
()¶Get whether the legend box patch is drawn
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_hanler_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.
get_legend_handler_map
()¶return the handler map.
get_lines
()¶return a list of lines.Line2D instances in the legend
get_patches
()¶return a list of patch instances in the legend
get_texts
()¶return a list of text.Text instance in the legend
get_title
()¶return Text instance for the legend title
get_window_extent
(*args, **kwargs)¶return a extent of the legend
set_bbox_to_anchor
(bbox, transform=None)¶set the bbox that the legend will be anchored.
bbox can be a BboxBase instance, a tuple of [left, bottom, width, height] in the given transform (normalized axes coordinate if None), or a tuple of [left, bottom] where the width and height will be assumed to be zero.
set_default_handler_map
(handler_map)¶A class method to set the default handler map.
set_frame_on
(b)¶Set whether the legend box patch is drawn
ACCEPTS: [ True | False ]
set_title
(title, prop=None)¶set the legend title. Fontproperties can be optionally set with prop parameter.
update_default_handler_map
(handler_map)¶A class method to update the default handler map.
zorder
= 5¶matplotlib.legend_handler
¶This module defines default legend handlers.
It is strongly encouraged to have read the legend guide before this documentation.
Legend handlers are expected to be a callable object with a following signature.
legend_handler(legend, orig_handle, fontsize, handlebox)
Where legend is the legend itself, orig_handle is the original plot, fontsize is the fontsize in pixles, and handlebox is a OffsetBox instance. Within the call, you should create relevant artists (using relevant properties from the legend and/or orig_handle) and add them into the handlebox. The artists needs to be scaled according to the fontsize (note that the size is in pixel, i.e., this is dpi-scaled value).
This module includes definition of several legend handler classes derived from the base class (HandlerBase) with the following method.
def legend_artist(self, legend, orig_handle, fontsize, handlebox):
matplotlib.legend_handler.
HandlerBase
(xpad=0.0, ypad=0.0, update_func=None)¶A Base class for default legend handlers.
The derived classes are meant to override create_artists method, which has a following signature.:
def create_artists(self, legend, orig_handle,
xdescent, ydescent, width, height, fontsize,
trans):
The overridden method needs to create artists of the given transform that fits in the given dimension (xdescent, ydescent, width, height) that are scaled by fontsize if necessary.
adjust_drawing_area
(legend, orig_handle, xdescent, ydescent, width, height, fontsize)¶create_artists
(legend, orig_handle, xdescent, ydescent, width, height, fontsize, trans)¶legend_artist
(legend, orig_handle, fontsize, handlebox)¶Return the artist that this HandlerBase generates for the given original artist/handle.
Parameters: | legend :
orig_handle :
fontsize : float or int
handlebox :
|
---|
update_prop
(legend_handle, orig_handle, legend)¶matplotlib.legend_handler.
HandlerCircleCollection
(yoffsets=None, sizes=None, **kw)¶Handler for CircleCollections
create_collection
(orig_handle, sizes, offsets, transOffset)¶matplotlib.legend_handler.
HandlerErrorbar
(xerr_size=0.5, yerr_size=None, marker_pad=0.3, numpoints=None, **kw)¶Handler for Errorbars
create_artists
(legend, orig_handle, xdescent, ydescent, width, height, fontsize, trans)¶get_err_size
(legend, xdescent, ydescent, width, height, fontsize)¶matplotlib.legend_handler.
HandlerLine2D
(marker_pad=0.3, numpoints=None, **kw)¶Handler for Line2D instances.
create_artists
(legend, orig_handle, xdescent, ydescent, width, height, fontsize, trans)¶matplotlib.legend_handler.
HandlerLineCollection
(marker_pad=0.3, numpoints=None, **kw)¶Handler for LineCollection instances.
create_artists
(legend, orig_handle, xdescent, ydescent, width, height, fontsize, trans)¶get_numpoints
(legend)¶matplotlib.legend_handler.
HandlerNpoints
(marker_pad=0.3, numpoints=None, **kw)¶get_numpoints
(legend)¶get_xdata
(legend, xdescent, ydescent, width, height, fontsize)¶matplotlib.legend_handler.
HandlerNpointsYoffsets
(numpoints=None, yoffsets=None, **kw)¶get_ydata
(legend, xdescent, ydescent, width, height, fontsize)¶matplotlib.legend_handler.
HandlerPatch
(patch_func=None, **kw)¶Handler for Patch instances.
The HandlerPatch class optionally takes a function patch_func
who’s responsibility is to create the legend key artist. The
patch_func
should have the signature:
def patch_func(legend=legend, orig_handle=orig_handle,
xdescent=xdescent, ydescent=ydescent,
width=width, height=height, fontsize=fontsize)
Subsequently the created artist will have its update_prop
method
called and the appropriate transform will be applied.
create_artists
(legend, orig_handle, xdescent, ydescent, width, height, fontsize, trans)¶matplotlib.legend_handler.
HandlerPathCollection
(yoffsets=None, sizes=None, **kw)¶Handler for PathCollections, which are used by scatter
create_collection
(orig_handle, sizes, offsets, transOffset)¶matplotlib.legend_handler.
HandlerPolyCollection
(xpad=0.0, ypad=0.0, update_func=None)¶Handler for PolyCollection used in fill_between and stackplot.
create_artists
(legend, orig_handle, xdescent, ydescent, width, height, fontsize, trans)¶matplotlib.legend_handler.
HandlerRegularPolyCollection
(yoffsets=None, sizes=None, **kw)¶Handler for RegularPolyCollections.
create_artists
(legend, orig_handle, xdescent, ydescent, width, height, fontsize, trans)¶create_collection
(orig_handle, sizes, offsets, transOffset)¶get_numpoints
(legend)¶get_sizes
(legend, orig_handle, xdescent, ydescent, width, height, fontsize)¶update_prop
(legend_handle, orig_handle, legend)¶matplotlib.legend_handler.
HandlerStem
(marker_pad=0.3, numpoints=None, bottom=None, yoffsets=None, **kw)¶Handler for Errorbars
create_artists
(legend, orig_handle, xdescent, ydescent, width, height, fontsize, trans)¶get_ydata
(legend, xdescent, ydescent, width, height, fontsize)¶matplotlib.legend_handler.
HandlerTuple
(**kwargs)¶Handler for Tuple
create_artists
(legend, orig_handle, xdescent, ydescent, width, height, fontsize, trans)¶matplotlib.legend_handler.
update_from_first_child
(tgt, src)¶