"""
LayerArtist classes handle the visualization of an individual subset
or dataset.
Visualization clients in Glue typically compose visualizations by stacking
visualizations of several datasets and subsets on top of each other. They
do this by creating and managing a collection of LayerArtists, one for
each Data or Subset to view.
LayerArtists contain the bulk of the logic for actually rendering things
"""
from __future__ import absolute_import, division, print_function
import os
from contextlib import contextmanager
from abc import ABCMeta
import numpy as np
from glue.external.echo.callback_container import CallbackContainer
from glue.external import six
from glue.core.subset import Subset
from glue.utils import Pointer, PropertySetMixin
from glue.core.message import LayerArtistEnabledMessage, LayerArtistDisabledMessage
__all__ = ['LayerArtistBase', 'LayerArtistContainer']
DISABLED_LAYER_WARNING = """
This layer depends on attributes that cannot be derived for the underlying
dataset. This usually indicates that this dataset has not been linked with other
datasets being shown. In this case, for this layer to work, it would need to be
linked with the following datasets: {}
""".replace(os.linesep, ' ')
DISABLED_MASK_MESSAGE = """
The subset mask for this layer cannot be computed. This usually indicates that
the selection was defined using attributes that are not defined in this dataset.
""".replace(os.linesep, ' ')
class ChangedTrigger(object):
"""Sets an instance's _changed attribute to True on update"""
def __init__(self, default=None):
self._default = default
self._vals = {}
def __get__(self, inst, type=None):
return self._vals.get(inst, self._default)
def __set__(self, inst, value):
if isinstance(value, np.ndarray):
changed = value is not self.__get__(inst)
else:
changed = value != self.__get__(inst)
self._vals[inst] = value
if changed:
inst._changed = True
[docs]@six.add_metaclass(ABCMeta)
class LayerArtistBase(PropertySetMixin):
_property_set = ['zorder', 'visible', 'layer']
# the order of this layer in the visualizations. High-zorder
# layers are drawn on top of low-zorder layers.
# Subclasses should refresh plots when this property changes
zorder = Pointer('_zorder')
# whether this layer should be rendered.
# Subclasses should refresh plots when this property changes
visible = Pointer('_visible')
# whether this layer is capable of being rendered
# Subclasses should refresh plots when this property changes
enabled = Pointer('_enabled')
def __init__(self, layer):
"""Create a new LayerArtist
Parameters
----------
layer : :class:`~glue.core.data.Data` or :class:`~glue.core.subset.Subset`
Data or Subset to draw
layer : :class:`~glue.core.data.Data` or `glue.core.subset.Subset`
"""
self._visible = True
self._zorder = 0
self._enabled = True
self._layer = layer
self.view = None # cache of last view, if relevant
self._state = None # cache of subset state, if relevant
self._changed = True # hint at whether underlying data has changed since last render
self._disabled_reason = '' # A string explaining why this layer is disabled.
[docs] def get_layer_color(self):
# This method can return either a plain color or a colormap. This is
# used by the UI layer to determine a 'representative' color or colormap
# for the layer to be used e.g. in icons.
return self._layer.style.color
[docs] def enable(self):
if self.enabled:
return
self._disabled_reason = ''
self._enabled = True
self.redraw()
if self._layer is not None and self._layer.hub is not None:
message = LayerArtistEnabledMessage(self)
self._layer.hub.broadcast(message)
[docs] def disable(self, reason):
"""
Disable the layer for a particular reason.
Layers should only be disabled when drawing is impossible,
e.g. because a subset cannot be applied to a dataset.
Parameters
----------
reason : str
A short explanation for why the layer can't be drawn.
Used by the UI
"""
self._disabled_reason = reason
self._enabled = False
self.clear()
if self._layer is not None and self._layer.hub is not None:
message = LayerArtistDisabledMessage(self)
self._layer.hub.broadcast(message)
[docs] def disable_invalid_attributes(self, *attributes):
"""
Disable a layer because visualization depends on knowing a set
of ComponentIDs that cannot be derived from a dataset or subset
Automatically generates a disabled message.
Parameters
----------
attributes : sequence of ComponentIDs
"""
if len(attributes) == 0:
self.disable('')
return
datasets = ', '.join(sorted(set([cid.parent.label for cid in attributes])))
self.disable(DISABLED_LAYER_WARNING.format(datasets))
[docs] def disable_incompatible_subset(self):
"""
Disable a layer because the subset mask cannot be computed.
Automatically generates a disabled message.
"""
self.disable(DISABLED_MASK_MESSAGE)
[docs] @property
def disabled_message(self):
"""
Returns why a layer is disabled
"""
if self.enabled:
return ''
return "Cannot visualize this layer: %s" % self._disabled_reason
@property
def layer(self):
"""
The Data or Subset visualized in this layer
"""
return self._layer
[docs] @layer.setter
def layer(self, value):
self._layer = value
[docs] def redraw(self):
"""
Re-render the plot
"""
pass
[docs] def update(self):
"""
Sync the visual appearance of the layer, and redraw
"""
pass
[docs] def clear(self):
"""
Clear the visualization for this layer
"""
pass
[docs] def remove(self):
"""
Remove the visualization for this layer.
This is called when the layer artist is removed for good from the
viewer. It defaults to calling clear, but can be overriden in cases
where clear and remove should be different.
"""
self.clear()
[docs] def force_update(self, *args, **kwargs):
"""
Sets the _changed flag to true, and calls update.
Force an update of the layer, overriding any
caching that might be going on for speed
"""
self._changed = True
return self.update(*args, **kwargs)
def _check_subset_state_changed(self):
"""Checks to see if layer is a subset and, if so,
if it has changed subset state. Sets _changed flag to True if so"""
if not isinstance(self.layer, Subset):
return
state = self.layer.subset_state
if state is not self._state:
self._changed = True
self._state = state
def __str__(self):
return "%s for %s" % (self.__class__.__name__, self.layer.label)
def __gluestate__(self, context):
# note, this doesn't yet have a restore method. Will rely on client
return dict((k, context.id(v)) for k, v in self.properties.items())
__repr__ = __str__
[docs]class LayerArtistContainer(object):
"""A collection of LayerArtists"""
def __init__(self):
self.artists = []
self.empty_callbacks = CallbackContainer()
self.change_callbacks = CallbackContainer()
self._ignore_empty_callbacks = False
self._ignore_change_callbacks = False
[docs] def on_empty(self, func):
"""
Register a callback function that should be invoked when
this container is emptied
"""
self.empty_callbacks.append(func)
[docs] def on_changed(self, func):
"""
Register a callback function that should be invoked when
this container's elements change
"""
self.change_callbacks.append(func)
def _duplicate(self, artist):
for a in self.artists:
if type(a) == type(artist) and a.layer is artist.layer:
return True
return False
[docs] def append(self, artist):
"""Add a LayerArtist to this collection"""
self.artists.append(artist)
artist.zorder = max(a.zorder for a in self.artists) + 1
self._notify()
[docs] def remove(self, artist):
"""Remove a LayerArtist from this collection
:param artist: The artist to remove
:type artist: :class:`LayerArtistBase`
"""
if artist in self.artists:
self.artists.remove(artist)
artist.remove()
self._notify()
[docs] def clear(self):
"""
Remove all layer artists from this collection
"""
for artist in self.artists:
artist.remove()
if six.PY2:
self.artists[:] = []
else:
self.artists.clear()
[docs] def clear_callbacks(self):
"""
Remove all callbacks
"""
self.empty_callbacks.clear()
self.change_callbacks.clear()
def _notify(self):
if not self._ignore_change_callbacks:
for cb in self.change_callbacks:
cb()
if not self._ignore_empty_callbacks and len(self) == 0:
for cb in self.empty_callbacks:
cb()
[docs] def pop(self, layer):
"""Remove all artists associated with a layer"""
to_remove = [a for a in self.artists if a.layer is layer]
for r in to_remove:
self.remove(r)
return to_remove
[docs] @property
def layers(self):
"""A list of the unique layers in the container"""
return list(set([a.layer for a in self.artists]))
[docs] @contextmanager
def ignore_empty(self):
"""
A context manager that temporarily disables calling callbacks if
container is empty.
"""
try:
self._ignore_empty_callbacks = True
yield
finally:
self._ignore_empty_callbacks = False
[docs] @contextmanager
def ignore_change(self):
"""
A context manager that temporarily disables calling callbacks if
container is changed.
"""
try:
self._ignore_change_callbacks = True
yield
finally:
self._ignore_change_callbacks = False
[docs] @contextmanager
def ignore_callbacks(self):
try:
self._ignore_change_callbacks = True
self._ignore_empty_callbacks = True
yield
finally:
self._ignore_change_callbacks = False
self._ignore_empty_callbacks = False
def __len__(self):
return len(self.artists)
def __iter__(self):
return iter(sorted(self.artists, key=lambda x: x.zorder))
def __contains__(self, item):
return any(item is a.layer for a in self.artists)
def __getitem__(self, layer):
if isinstance(layer, int):
return self.artists[layer]
return [a for a in self.artists if a.layer is layer]