matplotlib/lib/matplotlib/legend.py at master · gitj/matplotlib · GitHub

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"""

The legend module defines the Legend class, which is responsible for

drawing legends associated with axes and/or figures.

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 :mod:`~matplotlib.legend_handler` module). Note

that not all kinds of artist are supported by the legend yet (See

:ref:`plotting-guide-legend` for more information).

"""

from __future__ import division, print_function

import warnings

import numpy as np

from matplotlib import rcParams

from matplotlib.artist import Artist, allow_rasterization

from matplotlib.cbook import is_string_like, iterable, silent_list, safezip

from matplotlib.font_manager import FontProperties

from matplotlib.lines import Line2D

from matplotlib.patches import Patch, Rectangle, Shadow, FancyBboxPatch

from matplotlib.collections import LineCollection, RegularPolyCollection, \

CircleCollection, PathCollection

from matplotlib.transforms import Bbox, BboxBase, TransformedBbox

from matplotlib.transforms import BboxTransformTo, BboxTransformFrom

from matplotlib.offsetbox import HPacker, VPacker, TextArea, DrawingArea

from matplotlib.offsetbox import DraggableOffsetBox

from matplotlib.container import ErrorbarContainer, BarContainer, StemContainer

import legend_handler

class DraggableLegend(DraggableOffsetBox):

def __init__(self, legend, use_blit=False, update="loc"):

"""

update : If "loc", update *loc* parameter of

legend upon finalizing. If "bbox", update

*bbox_to_anchor* parameter.

"""

self.legend = legend

if update in ["loc", "bbox"]:

self._update = update

else:

raise ValueError("update parameter '%s' is not supported." %

update)

DraggableOffsetBox.__init__(self, legend, legend._legend_box,

use_blit=use_blit)

def artist_picker(self, legend, evt):

return self.legend.contains(evt)

def finalize_offset(self):

loc_in_canvas = self.get_loc_in_canvas()

if self._update == "loc":

self._update_loc(loc_in_canvas)

elif self._update == "bbox":

self._update_bbox_to_anchor(loc_in_canvas)

else:

raise RuntimeError("update parameter '%s' is not supported." %

self.update)

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 defaul 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_point(loc_in_canvas))

def _update_bbox_to_anchor(self, loc_in_canvas):

tr = self.legend.axes.transAxes

loc_in_bbox = tr.transform_point(loc_in_canvas)

self.legend.set_bbox_to_anchor(loc_in_bbox)

class Legend(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 axis 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 noramilzed coordinate values with

respect its parent.

"""

codes = {'best': 0, # only implemented for axis 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,

}

zorder = 5

def __str__(self):

return "Legend"

def __init__(self, parent, handles, labels,

loc=None,

numpoints=None, # the number of points in the legend line

markerscale=None, # the relative size of legend markers

# vs. original

scatterpoints=3, # TODO: may be an rcParam

scatteryoffsets=None,

prop=None, # properties for the legend texts

fontsize=None, # keyword to set font size directly

# the following dimensions are in axes coords

pad=None, # deprecated; use borderpad

labelsep=None, # deprecated; use labelspacing

handlelen=None, # deprecated; use handlelength

handletextsep=None, # deprecated; use handletextpad

axespad=None, # deprecated; use borderaxespad

# spacing & pad defined as a fraction of the font-size

borderpad=None, # the whitespace inside the legend border

labelspacing=None, # the vertical space between the legend

# entries

handlelength=None, # the length of the legend handles

handleheight=None, # the height of the legend handles

handletextpad=None, # the pad between the legend handle

# and text

borderaxespad=None, # the pad between the axes and legend

# border

columnspacing=None, # spacing between columns

ncol=1, # number of columns

mode=None, # mode for horizontal distribution of columns.

# None, "expand"

fancybox=None, # True use a fancy box, false use a rounded

# box, none use rc

shadow=None,

title=None, # set a title for the legend

bbox_to_anchor=None, # bbox that the legend will be anchored.

bbox_transform=None, # transform for the bbox

frameon=None, # draw frame

handler_map=None,

"""

- *parent*: the artist that contains the legend

- *handles*: a list of artists (lines, patches) to be added to the

legend

- *labels*: a list of strings to label the legend

Optional keyword arguments:

================ ====================================================

Keyword Description

================ ====================================================

loc a location code

prop the font property

fontsize the font size (used only if prop is not specified)

markerscale the relative size of legend markers vs. original

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 a frame around the legend.

If None, use rc

fancybox if True, draw a frame with a round fancybox.

If None, use rc

shadow if True, draw a shadow behind legend

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 length 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 :meth:`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.

"""

# local import only to avoid circularity

from matplotlib.axes import Axes

from matplotlib.figure import Figure

Artist.__init__(self)

if prop is None:

if fontsize is not None:

self.prop = FontProperties(size=fontsize)

else:

self.prop = FontProperties(size=rcParams["legend.fontsize"])

elif isinstance(prop, dict):

self.prop = FontProperties(**prop)

if "size" not in prop:

self.prop.set_size(rcParams["legend.fontsize"])

else:

self.prop = prop

self._fontsize = self.prop.get_size_in_points()

propnames = ["numpoints", "markerscale", "shadow", "columnspacing",

"scatterpoints", "handleheight"]

self.texts = []

self.legendHandles = []

self._legend_title_box = None

self._handler_map = handler_map

localdict = locals()

for name in propnames:

if localdict[name] is None:

value = rcParams["legend." + name]

else:

value = localdict[name]

setattr(self, name, value)

# Take care the deprecated keywords

deprecated_kwds = {"pad": "borderpad",

"labelsep": "labelspacing",

"handlelen": "handlelength",

"handletextsep": "handletextpad",

"axespad": "borderaxespad"}

# convert values of deprecated keywords (ginve in axes coords)

# to new vaules in a fraction of the font size

# conversion factor

bbox = parent.bbox

axessize_fontsize = min(bbox.width, bbox.height) / self._fontsize

for k, v in deprecated_kwds.iteritems():

# use deprecated value if not None and if their newer

# counter part is None.

if localdict[k] is not None and localdict[v] is None:

warnings.warn("Use '%s' instead of '%s'." % (v, k),

DeprecationWarning)

setattr(self, v, localdict[k] * axessize_fontsize)

continue

# Otherwise, use new keywords

if localdict[v] is None:

setattr(self, v, rcParams["legend." + v])

else:

setattr(self, v, localdict[v])

del localdict

handles = list(handles)

if len(handles) < 2:

ncol = 1

self._ncol = 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 = int(self.scatterpoints / len(self._scatteryoffsets)) + 1

self._scatteryoffsets = np.tile(self._scatteryoffsets,

reps)[:self.scatterpoints]

# _legend_box is an OffsetBox 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.set_axes(parent)

self.set_figure(parent.figure)

elif isinstance(parent, Figure):

self.isaxes = False

self.set_figure(parent)

else:

raise TypeError("Legend needs either Axes or Figure as parent")

self.parent = parent

if loc is None:

loc = rcParams["legend.loc"]

if not self.isaxes and loc in [0, 'best']:

loc = 'upper right'

if is_string_like(loc):

if loc not in self.codes:

if self.isaxes:

warnings.warn('Unrecognized location "%s". Falling back '

'on "best"; valid locations are\n\t%s\n'

% (loc, '\n\t'.join(self.codes.iterkeys())))

loc = 0

else:

warnings.warn('Unrecognized location "%s". Falling back '

'on "upper right"; '

'valid locations are\n\t%s\n'

% (loc, '\n\t'.join(self.codes.iterkeys())))

loc = 1

else:

loc = self.codes[loc]

if not self.isaxes and loc == 0:

warnings.warn('Automatic legend placement (loc="best") not '

'implemented for figure legend. '

'Falling back on "upper right".')

loc = 1

self._mode = mode

self.set_bbox_to_anchor(bbox_to_anchor, bbox_transform)

# We use FancyBboxPatch to draw a legend frame. The location

# and size of the box will be updated during the drawing time.

self.legendPatch = FancyBboxPatch(

xy=(0.0, 0.0), width=1., height=1.,

facecolor=rcParams["axes.facecolor"],

edgecolor=rcParams["axes.edgecolor"],

mutation_scale=self._fontsize,

snap=True

)

# The width and height of the legendPatch will be set (in the

# draw()) to the length that includes the padding. Thus we set

# pad=0 here.

if fancybox is None:

fancybox = rcParams["legend.fancybox"]

if fancybox:

self.legendPatch.set_boxstyle("round", pad=0,

rounding_size=0.2)

else:

self.legendPatch.set_boxstyle("square", pad=0)

self._set_artist_props(self.legendPatch)

self._drawFrame = frameon

if frameon is None:

self._drawFrame = rcParams["legend.frameon"]

# init with null renderer

self._init_legend_box(handles, labels)

self._loc = loc

self.set_title(title)

self._last_fontsize_points = self._fontsize

self._draggable = None

def _set_artist_props(self, a):

"""

set the boilerplate props for artists added to axes

"""

a.set_figure(self.figure)

if self.isaxes:

a.set_axes(self.axes)

a.set_transform(self.get_transform())

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_real = loc

if loc == 0:

_findoffset = self._findoffset_best

else:

_findoffset = self._findoffset_loc

#def findoffset(width, height, xdescent, ydescent):

# return _findoffset(width, height, xdescent, ydescent, renderer)

self._legend_box.set_offset(_findoffset)

self._loc_real = loc

def _get_loc(self):

return self._loc_real

_loc = property(_get_loc, _set_loc)

def _findoffset_best(self, width, height, xdescent, ydescent, renderer):

"Helper function to locate the legend at its best position"

ox, oy = self._find_best_position(width, height, renderer)

return ox + xdescent, oy + ydescent

def _findoffset_loc(self, width, height, xdescent, ydescent, renderer):

"Helper function to locate the legend using the location code"

if iterable(self._loc) and len(self._loc) == 2:

# when loc is a tuple of 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

else:

bbox = Bbox.from_bounds(0, 0, width, height)

x, y = self._get_anchored_bbox(self._loc, bbox,

self.get_bbox_to_anchor(),

renderer)

return x + xdescent, y + ydescent

@allow_rasterization

def draw(self, renderer):

"Draw everything that belongs to the legend"

if not self.get_visible():

return

renderer.open_group('legend')

fontsize = renderer.points_to_pixels(self._fontsize)

# if mode == fill, set the width of the legend_box to the

# width of the paret (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)

if self._drawFrame:

# update the location and size of the legend

bbox = self._legend_box.get_window_extent(renderer)

self.legendPatch.set_bounds(bbox.x0, bbox.y0,

bbox.width, bbox.height)

self.legendPatch.set_mutation_scale(fontsize)

if self.shadow:

shadow = Shadow(self.legendPatch, 2, -2)

shadow.draw(renderer)

self.legendPatch.draw(renderer)

self._legend_box.draw(renderer)

renderer.close_group('legend')

def _approx_text_height(self, renderer=None):

"""

Return the approximate height of the text. This is used to place

the legend handle.

"""

if renderer is None:

return self._fontsize

else:

return renderer.points_to_pixels(self._fontsize)

# _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(),

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()

}

# (get|set|update)_default_handler_maps are public interfaces to

# modify the defalut handler map.

@classmethod

def get_default_handler_map(cls):

"""

A class method that returns the default handler map.

"""

return cls._default_handler_map

@classmethod

def set_default_handler_map(cls, handler_map):

"""

A class method to set the default handler map.

"""

cls._default_handler_map = handler_map

@classmethod

def update_default_handler_map(cls, handler_map):

"""

A class method to update the default handler map.

"""

cls._default_handler_map.update(handler_map)

def get_legend_handler_map(self):

"""

return the handler map.

"""

default_handler_map = self.get_default_handler_map()

if self._handler_map:

hm = default_handler_map.copy()

hm.update(self._handler_map)

return hm

else:

return 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_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.

"""

legend_handler_keys = legend_handler_map.keys()

if orig_handle in legend_handler_keys:

handler = legend_handler_map[orig_handle]

else:

for handle_type in type(orig_handle).mro():

if handle_type in legend_handler_map:

handler = legend_handler_map[handle_type]

break

else:

handler = None

return handler

def _init_legend_box(self, handles, labels):

"""

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 HPacker packed with

# legend handleBox and labelBox. handleBox is an instance of

# offsetbox.DrawingArea which contains legend handle. labelBox

# is an instance of offsetbox.TextArea which contains legend

# text.

text_list = [] # the list of text instances

handle_list = [] # the list of text instances

label_prop = dict(verticalalignment='baseline',

horizontalalignment='left',

fontproperties=self.prop,

)

labelboxes = []

handleboxes = []

# The approximate height and descent of text. These values are

# only used for plotting the legend handle.

descent = 0.35 * self._approx_text_height() * (self.handleheight - 0.7)

# 0.35 and 0.7 are just heuristic numbers. this may need to be improbed

height = self._approx_text_height() * 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_trasnform(). If the artist does not uses its

# default trasnform (eg, Collections), you need to

# manually set their transform to the self.get_transform().

legend_handler_map = self.get_legend_handler_map()

for orig_handle, lab in zip(handles, labels):

handler = self.get_legend_handler(legend_handler_map, orig_handle)

if handler is None:

warnings.warn(

"Legend does not support %s\nUse proxy artist "

"instead.\n\n"

"http://matplotlib.sourceforge.net/users/legend_guide.html#using-proxy-artist\n" %

(str(orig_handle),))

handle_list.append(None)

continue

textbox = TextArea(lab, textprops=label_prop,

multilinebaseline=True, minimumdescent=True)

text_list.append(textbox._text)

labelboxes.append(textbox)

handlebox = DrawingArea(width=self.handlelength * fontsize,

height=height,

xdescent=0., ydescent=descent)

handle = handler(self, orig_handle,

#xdescent, ydescent, width, height,

fontsize,

handlebox)

handle_list.append(handle)

handleboxes.append(handlebox)

if len(handleboxes) > 0:

# We calculate number of rows in each column. The first

# (num_largecol) columns will have (nrows+1) rows, and remaining

# (num_smallcol) columns will have (nrows) rows.

ncol = min(self._ncol, len(handleboxes))

nrows, num_largecol = divmod(len(handleboxes), ncol)

num_smallcol = ncol - num_largecol

# starting index of each column and number of rows in it.

largecol = safezip(range(0,

num_largecol * (nrows + 1),

(nrows + 1)),

[nrows + 1] * num_largecol)

smallcol = safezip(range(num_largecol * (nrows + 1),

len(handleboxes),

nrows),

[nrows] * num_smallcol)

else:

largecol, smallcol = [], []

handle_label = safezip(handleboxes, labelboxes)

columnbox = []

for i0, di in largecol + smallcol:

# pack handleBox and labelBox into itemBox

itemBoxes = [HPacker(pad=0,

sep=self.handletextpad * fontsize,

children=[h, t], align="baseline")

for h, t in handle_label[i0:i0 + di]]

# minimumdescent=False for the text of the last row of the column

itemBoxes[-1].get_children()[1].set_minimumdescent(False)

# pack columnBox

columnbox.append(VPacker(pad=0,

sep=self.labelspacing * fontsize,

align="baseline",

children=itemBoxes))

if self._mode == "expand":

mode = "expand"

else:

mode = "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="center",

children=[self._legend_title_box,

self._legend_handle_box])

self._legend_box.set_figure(self.figure)

self.texts = text_list

self.legendHandles = handle_list

def _auto_legend_data(self):

"""

Returns list of vertices and extents covered by the plot.

Returns a two long list.

First element is a list of (x, y) vertices (in

display-coordinates) covered by all the lines and line

collections, in the legend's handles.

Second element is a list of bounding boxes for all the patches in

the legend's handles.

"""

# should always hold because function is only called internally

assert self.isaxes

ax = self.parent

vertices = []

bboxes = []

lines = []

for handle in ax.lines:

assert isinstance(handle, Line2D)

path = handle.get_path()

trans = handle.get_transform()

tpath = trans.transform_path(path)

lines.append(tpath)

for handle in ax.patches:

assert isinstance(handle, Patch)

if isinstance(handle, Rectangle):

transform = handle.get_data_transform()

bboxes.append(handle.get_bbox().transformed(transform))

else:

transform = handle.get_transform()

bboxes.append(handle.get_path().get_extents(transform))

return [vertices, bboxes, lines]

def draw_frame(self, b):

'b is a boolean. Set draw frame to b'

self.set_frame_on(b)

def get_children(self):

'return a list of child artists'

children = []

if self._legend_box:

children.append(self._legend_box)

children.extend(self.get_lines())

children.extend(self.get_patches())

children.extend(self.get_texts())

children.append(self.get_frame())

if self._legend_title_box:

children.append(self.get_title())

return children

def get_frame(self):

'return the Rectangle instance used to frame the legend'

return self.legendPatch

def get_lines(self):

'return a list of lines.Line2D instances in the legend'

return [h for h in self.legendHandles if isinstance(h, Line2D)]

def get_patches(self):

'return a list of patch instances in the legend'

return silent_list('Patch',

[h for h in self.legendHandles

if isinstance(h, Patch)])

def get_texts(self):

'return a list of text.Text instance in the legend'

return silent_list('Text', self.texts)

def set_title(self, title, prop=None):

"""

set the legend title. Fontproperties can be optionally set

with *prop* parameter.

"""

self._legend_title_box._text.set_text(title)

if prop is not None:

if isinstance(prop, dict):

prop = FontProperties(**prop)

self._legend_title_box._text.set_fontproperties(prop)

if title:

self._legend_title_box.set_visible(True)

else:

self._legend_title_box.set_visible(False)

def get_title(self):

'return Text instance for the legend title'

return self._legend_title_box._text

def get_window_extent(self, *args, **kwargs):

'return a extent of the the legend'

return self.legendPatch.get_window_extent(*args, **kwargs)

def get_frame_on(self):

"""

Get whether the legend box patch is drawn

"""

return self._drawFrame

def set_frame_on(self, b):

"""

Set whether the legend box patch is drawn

ACCEPTS: [ *True* | *False* ]

"""

self._drawFrame = b

def get_bbox_to_anchor(self):

"""

return the bbox that the legend will be anchored

"""

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.

*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.

"""

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:

raise ValueError("Invalid argument for bbox : %s" % str(bbox))

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)

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.

- loc: a location code in range(1, 11).

This corresponds to the possible values for self._loc, excluding

"best".

- bbox: bbox to be placed, display coodinate units.

- parentbbox: a parent box which will contain the bbox. In

display coordinates.

"""

assert loc in range(1, 11) # called only internally

BEST, UR, UL, LL, LR, R, CL, CR, LC, UC, C = range(11)

anchor_coefs = {UR: "NE",

UL: "NW",

LL: "SW",

LR: "SE",

R: "E",

CL: "W",

CR: "E",

LC: "S",

UC: "N",

C: "C"}

c = anchor_coefs[loc]

fontsize = renderer.points_to_pixels(self._fontsize)

container = parentbbox.padded(-(self.borderaxespad) * fontsize)

anchored_box = bbox.anchored(c, container=container)

return anchored_box.x0, anchored_box.y0

def _find_best_position(self, width, height, renderer, consider=None):

"""

Determine the best location to place the legend.

`consider` is a list of (x, y) pairs to consider as a potential

lower-left corner of the legend. All are display coords.

"""

# should always hold because function is only called internally

assert self.isaxes

verts, bboxes, lines = self._auto_legend_data()

bbox = Bbox.from_bounds(0, 0, width, height)

consider = [self._get_anchored_bbox(x, bbox, self.get_bbox_to_anchor(),

renderer)

for x

in range(1, len(self.codes))]

#tx, ty = self.legendPatch.get_x(), self.legendPatch.get_y()

candidates = []

for l, b in consider:

legendBox = Bbox.from_bounds(l, b, width, height)

badness = 0

badness = legendBox.count_contains(verts)

badness += legendBox.count_overlaps(bboxes)

for line in lines:

if line.intersects_bbox(legendBox):

badness += 1

ox, oy = l, b

if badness == 0:

return ox, oy

candidates.append((badness, (l, b)))

# rather than use min() or list.sort(), do this so that we are assured

# that in the case of two equal badnesses, the one first considered is

# returned.

# NOTE: list.sort() is stable.But leave as it is for now. -JJL

minCandidate = candidates[0]

for candidate in candidates:

if candidate[0] < minCandidate[0]:

minCandidate = candidate

ox, oy = minCandidate[1]

return ox, oy

def contains(self, event):

return self.legendPatch.contains(event)

def draggable(self, 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.

"""

is_draggable = self._draggable is not None

# if state is None we'll toggle

if state is None:

state = not is_draggable

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

matplotlib/lib/matplotlib/legend.py at master · gitj/matplotlib · GitHub

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