Source code for mplcursors._mplcursors

from collections import Counter
from collections.abc import Iterable
from contextlib import suppress
import copy
from functools import partial
import sys
import weakref
from weakref import WeakKeyDictionary

from matplotlib.axes import Axes
from matplotlib.container import Container
from matplotlib.figure import Figure
import numpy as np

from . import _pick_info


_default_bindings = dict(
    select=1,
    deselect=3,
    left="shift+left",
    right="shift+right",
    up="shift+up",
    down="shift+down",
    toggle_enabled="e",
    toggle_visible="v",
)
_default_annotation_kwargs = dict(
    bbox=dict(
        boxstyle="round,pad=.5",
        fc="yellow",
        alpha=.5,
        ec="k",
    ),
    arrowprops=dict(
        arrowstyle="->",
        connectionstyle="arc3",
        shrinkB=0,
        ec="k",
    ),
)
_default_annotation_positions = [
    dict(position=(-15, 15), anncoords="offset points",
         ha="right", va="bottom"),
    dict(position=(15, 15), anncoords="offset points",
         ha="left", va="bottom"),
    dict(position=(15, -15), anncoords="offset points",
         ha="left", va="top"),
    dict(position=(-15, -15), anncoords="offset points",
         ha="right", va="top"),
]
_default_highlight_kwargs = dict(
    # Only the kwargs corresponding to properties of the artist will be passed.
    # Line2D.
    color="yellow",
    markeredgecolor="yellow",
    linewidth=3,
    markeredgewidth=3,
    # PathCollection.
    facecolor="yellow",
    edgecolor="yellow",
)


class _MarkedStr(str):
    """A string subclass solely for marking purposes."""


def _get_rounded_intersection_area(bbox_1, bbox_2):
    """Compute the intersection area between two bboxes rounded to 8 digits."""
    # The rounding allows sorting areas without floating point issues.
    bbox = bbox_1.intersection(bbox_1, bbox_2)
    return round(bbox.width * bbox.height, 8) if bbox else 0


def _iter_axes_subartists(ax):
    r"""Yield all child `Artist`\s (*not* `Container`\s) of *ax*."""
    yield from ax.collections
    yield from ax.images
    yield from ax.lines
    yield from ax.patches
    yield from ax.texts


def _is_alive(artist):
    """Check whether *artist* is still present on its parent axes."""
    return bool(artist
                and artist.axes
                and (artist.container in artist.axes.containers
                     if isinstance(artist, _pick_info.ContainerArtist) else
                     artist in _iter_axes_subartists(artist.axes)))


def _reassigned_axes_event(event, ax):
    """Reassign *event* to *ax*."""
    event = copy.copy(event)
    event.xdata, event.ydata = (
        ax.transData.inverted().transform((event.x, event.y)))
    return event


[docs]class Cursor: """ A cursor for selecting Matplotlib artists. Attributes ---------- bindings : dict See the *bindings* keyword argument to the constructor. annotation_kwargs : dict See the *annotation_kwargs* keyword argument to the constructor. annotation_positions : dict See the *annotation_positions* keyword argument to the constructor. highlight_kwargs : dict See the *highlight_kwargs* keyword argument to the constructor. """ _keep_alive = WeakKeyDictionary()
[docs] def __init__(self, artists, *, multiple=False, highlight=False, hover=False, bindings=None, annotation_kwargs=None, annotation_positions=None, highlight_kwargs=None): """ Construct a cursor. Parameters ---------- artists : List[Artist] A list of artists that can be selected by this cursor. multiple : bool, optional Whether multiple artists can be "on" at the same time (defaults to False). highlight : bool, optional Whether to also highlight the selected artist. If so, "highlighter" artists will be placed as the first item in the :attr:`extras` attribute of the `Selection`. hover : bool, optional Whether to select artists upon hovering instead of by clicking. (Hovering over an artist while a button is pressed will not trigger a selection; right clicking on an annotation will still remove it.) bindings : dict, optional A mapping of button and keybindings to actions. Valid entries are: ================ ================================================== 'select' mouse button to select an artist (default: 1) 'deselect' mouse button to deselect an artist (default: 3) 'left' move to the previous point in the selected path, or to the left in the selected image (default: shift+left) 'right' move to the next point in the selected path, or to the right in the selected image (default: shift+right) 'up' move up in the selected image (default: shift+up) 'down' move down in the selected image (default: shift+down) 'toggle_enabled' toggle whether the cursor is active (default: e) 'toggle_visible' toggle default cursor visibility and apply it to all cursors (default: v) ================ ================================================== Missing entries will be set to the defaults. In order to not assign any binding to an action, set it to ``None``. annotation_kwargs : dict, optional Keyword argments passed to the `annotate <matplotlib.axes.Axes.annotate>` call. annotation_positions : List[dict], optional List of positions tried by the annotation positioning algorithm. highlight_kwargs : dict, optional Keyword arguments used to create a highlighted artist. """ artists = [*artists] # Be careful with GC. self._artists = [weakref.ref(artist) for artist in artists] for artist in artists: type(self)._keep_alive.setdefault(artist, set()).add(self) self._multiple = multiple self._highlight = highlight self._visible = True self._enabled = True self._selections = [] self._last_auto_position = None self._callbacks = {"add": [], "remove": []} connect_pairs = [("key_press_event", self._on_key_press)] if hover: connect_pairs += [ ("motion_notify_event", self._hover_handler), ("button_press_event", self._hover_handler)] else: connect_pairs += [ ("button_press_event", self._nonhover_handler)] self._disconnectors = [ partial(canvas.mpl_disconnect, canvas.mpl_connect(*pair)) for pair in connect_pairs for canvas in {artist.figure.canvas for artist in artists}] bindings = {**_default_bindings, **(bindings if bindings is not None else {})} unknown_bindings = {*bindings} - {*_default_bindings} if unknown_bindings: raise ValueError("Unknown binding(s): {}".format( ", ".join(sorted(unknown_bindings)))) duplicate_bindings = [ k for k, v in Counter(bindings.values()).items() if v > 1] if duplicate_bindings: raise ValueError("Duplicate binding(s): {}".format( ", ".join(sorted(map(str, duplicate_bindings))))) self.bindings = bindings self.annotation_kwargs = ( annotation_kwargs if annotation_kwargs is not None else copy.deepcopy(_default_annotation_kwargs)) self.annotation_positions = ( annotation_positions if annotation_positions is not None else copy.deepcopy(_default_annotation_positions)) self.highlight_kwargs = ( highlight_kwargs if highlight_kwargs is not None else copy.deepcopy(_default_highlight_kwargs))
@property def artists(self): """The tuple of selectable artists.""" # Work around matplotlib/matplotlib#6982: `cla()` does not clear # `.axes`. return tuple(filter(_is_alive, (ref() for ref in self._artists))) @property def enabled(self): """Whether clicks are registered for picking and unpicking events.""" return self._enabled @enabled.setter def enabled(self, value): self._enabled = value @property def selections(self): r"""The tuple of current `Selection`\s.""" for sel in self._selections: if sel.annotation.axes is None: raise RuntimeError("Annotation unexpectedly removed; " "use 'cursor.remove_selection' instead") return tuple(self._selections) @property def visible(self): """ Whether selections are visible by default. Setting this property also updates the visibility status of current selections. """ return self._visible @visible.setter def visible(self, value): self._visible = value for sel in self.selections: sel.annotation.set_visible(value) sel.annotation.figure.canvas.draw_idle() def _get_figure(self, aoc): """Return the parent figure of artist-or-container *aoc*.""" if isinstance(aoc, Container): try: ca, = {artist for artist in (ref() for ref in self._artists) if isinstance(artist, _pick_info.ContainerArtist) and artist.container is aoc} except ValueError: raise ValueError(f"Cannot find parent figure of {aoc}") return ca.figure else: return aoc.figure def _get_axes(self, aoc): """Return the parent axes of artist-or-container *aoc*.""" if isinstance(aoc, Container): try: ca, = {artist for artist in (ref() for ref in self._artists) if isinstance(artist, _pick_info.ContainerArtist) and artist.container is aoc} except ValueError: raise ValueError(f"Cannot find parent axes of {aoc}") return ca.axes else: return aoc.axes
[docs] def add_selection(self, pi): """ Create an annotation for a `Selection` and register it. Returns a new `Selection`, that has been registered by the `Cursor`, with the added annotation set in the :attr:`annotation` field and, if applicable, the highlighting artist in the :attr:`extras` field. Emits the ``"add"`` event with the new `Selection` as argument. When the event is emitted, the position of the annotation is temporarily set to ``(nan, nan)``; if this position is not explicitly set by a callback, then a suitable position will be automatically computed. Likewise, if the text alignment is not explicitly set but the position is, then a suitable alignment will be automatically computed. """ # pi: "pick_info", i.e. an incomplete selection. # Pre-fetch the figure and axes, as callbacks may actually unset them. figure = self._get_figure(pi.artist) axes = self._get_axes(pi.artist) if axes.get_renderer_cache() is None: figure.canvas.draw() # Needed by draw_artist below anyways. renderer = axes.get_renderer_cache() ann = axes.annotate( _pick_info.get_ann_text(*pi), xy=pi.target, xytext=(np.nan, np.nan), ha=_MarkedStr("center"), va=_MarkedStr("center"), visible=self.visible, **self.annotation_kwargs) ann.draggable(use_blit=not self._multiple) extras = [] if self._highlight: hl = self.add_highlight(*pi) if hl: extras.append(hl) sel = pi._replace(annotation=ann, extras=extras) self._selections.append(sel) for cb in self._callbacks["add"]: cb(sel) # Check that `ann.axes` is still set, as callbacks may have removed the # annotation. if ann.axes and ann.xyann == (np.nan, np.nan): fig_bbox = figure.get_window_extent() ax_bbox = axes.get_window_extent() overlaps = [] for idx, annotation_position in enumerate( self.annotation_positions): ann.set(**annotation_position) # Work around matplotlib/matplotlib#7614: position update is # missing. ann.update_positions(renderer) bbox = ann.get_window_extent(renderer) overlaps.append( (_get_rounded_intersection_area(fig_bbox, bbox), _get_rounded_intersection_area(ax_bbox, bbox), # Avoid needlessly jumping around by breaking ties using # the last used position as default. idx == self._last_auto_position)) auto_position = max(range(len(overlaps)), key=overlaps.__getitem__) ann.set(**self.annotation_positions[auto_position]) self._last_auto_position = auto_position else: if isinstance(ann.get_ha(), _MarkedStr): ann.set_ha({-1: "right", 0: "center", 1: "left"}[ np.sign(np.nan_to_num(ann.xyann[0]))]) if isinstance(ann.get_va(), _MarkedStr): ann.set_va({-1: "top", 0: "center", 1: "bottom"}[ np.sign(np.nan_to_num(ann.xyann[1]))]) if (extras or len(self.selections) > 1 and not self._multiple or not figure.canvas.supports_blit): # Either: # - there may be more things to draw, or # - annotation removal will make a full redraw necessary, or # - blitting is not (yet) supported. figure.canvas.draw_idle() elif ann.axes: # Fast path, only needed if the annotation has not been immediately # removed. figure.draw_artist(ann) # Explicit argument needed on MacOSX backend. figure.canvas.blit(figure.bbox) # Removal comes after addition so that the fast blitting path works. if not self._multiple: for sel in self.selections[:-1]: self.remove_selection(sel) return sel
[docs] def add_highlight(self, artist, *args, **kwargs): """ Create, add, and return a highlighting artist. This method is should be called with an "unpacked" `Selection`, possibly with some fields set to None. It is up to the caller to register the artist with the proper `Selection` (by calling ``sel.extras.append`` on the result of this method) in order to ensure cleanup upon deselection. """ hl = _pick_info.make_highlight( artist, *args, **{"highlight_kwargs": self.highlight_kwargs, **kwargs}) if hl: artist.axes.add_artist(hl) return hl
[docs] def connect(self, event, func=None): """ Connect a callback to a `Cursor` event; return the callback. Two events can be connected to: - callbacks connected to the ``"add"`` event are called when a `Selection` is added, with that selection as only argument; - callbacks connected to the ``"remove"`` event are called when a `Selection` is removed, with that selection as only argument. This method can also be used as a decorator:: @cursor.connect("add") def on_add(sel): ... Examples of callbacks:: # Change the annotation text and alignment: lambda sel: sel.annotation.set( text=sel.artist.get_label(), # or use e.g. sel.target.index ha="center", va="bottom") # Make label non-draggable: lambda sel: sel.draggable(False) """ if event not in self._callbacks: raise ValueError(f"{event!r} is not a valid cursor event") if func is None: return partial(self.connect, event) self._callbacks[event].append(func) return func
[docs] def disconnect(self, event, cb): """ Disconnect a previously connected callback. If a callback is connected multiple times, only one connection is removed. """ try: self._callbacks[event].remove(cb) except KeyError: raise ValueError(f"{event!r} is not a valid cursor event") except ValueError: raise ValueError(f"Callback {cb} is not registered to {event}")
[docs] def remove(self): """ Remove a cursor. Remove all `Selection`\\s, disconnect all callbacks, and allow the cursor to be garbage collected. """ for disconnectors in self._disconnectors: disconnectors() for sel in self.selections: self.remove_selection(sel) for s in type(self)._keep_alive.values(): with suppress(KeyError): s.remove(self)
def _nonhover_handler(self, event): if event.name == "button_press_event": if event.button == self.bindings["select"]: self._on_select_button_press(event) if event.button == self.bindings["deselect"]: self._on_deselect_button_press(event) def _hover_handler(self, event): if event.name == "motion_notify_event" and event.button is None: # Filter away events where the mouse is pressed, in particular to # avoid conflicts between hover and draggable. self._on_select_button_press(event) elif (event.name == "button_press_event" and event.button == self.bindings["deselect"]): # Still allow removing the annotation by right clicking. self._on_deselect_button_press(event) def _filter_mouse_event(self, event): # Accept the event iff we are enabled, and either # - no other widget is active, and this is not the second click of a # double click (to prevent double selection), or # - another widget is active, and this is a double click (to bypass # the widget lock). return (self.enabled and event.canvas.widgetlock.locked() == event.dblclick) def _on_select_button_press(self, event): if not self._filter_mouse_event(event): return # Work around lack of support for twinned axes. per_axes_event = {ax: _reassigned_axes_event(event, ax) for ax in {artist.axes for artist in self.artists}} pis = [] for artist in self.artists: if (artist.axes is None # Removed or figure-level artist. or event.canvas is not artist.figure.canvas or not artist.axes.contains(event)[0]): # Cropped by axes. continue pi = _pick_info.compute_pick(artist, per_axes_event[artist.axes]) if pi and not any((pi.artist, tuple(pi.target)) == (other.artist, tuple(other.target)) for other in self._selections): pis.append(pi) if not pis: return self.add_selection(min(pis, key=lambda pi: pi.dist)) def _on_deselect_button_press(self, event): if not self._filter_mouse_event(event): return for sel in self.selections[::-1]: # LIFO. ann = sel.annotation if event.canvas is not ann.figure.canvas: continue contained, _ = ann.contains(event) if contained: self.remove_selection(sel) break def _on_key_press(self, event): if event.key == self.bindings["toggle_enabled"]: self.enabled = not self.enabled elif event.key == self.bindings["toggle_visible"]: self.visible = not self.visible try: sel = self.selections[-1] except IndexError: return for key in ["left", "right", "up", "down"]: if event.key == self.bindings[key]: self.remove_selection(sel) self.add_selection(_pick_info.move(*sel, key=key)) break
[docs] def remove_selection(self, sel): """Remove a `Selection`.""" self._selections.remove(sel) # <artist>.figure will be unset so we save them first. figures = {artist.figure for artist in [sel.annotation] + sel.extras} # ValueError is raised if the artist has already been removed. with suppress(ValueError): sel.annotation.remove() for artist in sel.extras: with suppress(ValueError): artist.remove() for cb in self._callbacks["remove"]: cb(sel) for figure in figures: figure.canvas.draw_idle()
[docs]def cursor(pickables=None, **kwargs): """ Create a `Cursor` for a list of artists, containers, and axes. Parameters ---------- pickables : Optional[List[Union[Artist, Container, Axes, Figure]]] All artists and containers in the list or on any of the axes or figures passed in the list are selectable by the constructed `Cursor`. Defaults to all artists and containers on any of the figures that :mod:`~matplotlib.pyplot` is tracking. Note that the latter will only work when relying on pyplot, not when figures are directly instantiated (e.g., when manually embedding Matplotlib in a GUI toolkit). **kwargs Keyword arguments are passed to the `Cursor` constructor. """ if pickables is None: # Do not import pyplot ourselves to avoid forcing the backend. plt = sys.modules.get("matplotlib.pyplot") pickables = [ plt.figure(num) for num in plt.get_fignums()] if plt else [] elif (isinstance(pickables, Container) or not isinstance(pickables, Iterable)): pickables = [pickables] def iter_unpack_figures(pickables): for entry in pickables: if isinstance(entry, Figure): yield from entry.axes else: yield entry def iter_unpack_axes(pickables): for entry in pickables: if isinstance(entry, Axes): yield from _iter_axes_subartists(entry) containers.extend(entry.containers) elif isinstance(entry, Container): containers.append(entry) else: yield entry containers = [] artists = [*iter_unpack_axes(iter_unpack_figures(pickables))] for container in containers: contained = [*filter(None, container.get_children())] for artist in contained: with suppress(ValueError): artists.remove(artist) if contained: artists.append(_pick_info.ContainerArtist(container)) return Cursor(artists, **kwargs)