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Move multi-view overlay components in from `pyqtgraph` PR 

This brings in the WIP components developed as part of
https://github.com/pyqtgraph/pyqtgraph/pull/2162.

Most of the history can be understood from that issue and effort but the
TL;DR is,

- add an event handler wrapper system which can be used to
  wrap `ViewBox` methods such that multiple views can be overlayed and
  a single event stream broadcast from one "main" view to others which
  are overlaid with it.
- add in 2 relay `Signal` attrs to our `ViewBox` subtype (`Chartview`)
  to accomplish per event `MouseEvent.emit()` style broadcasting to
  multiple (sub-)views.
- Add a `PlotItemOverlay` api which does all the work of overlaying the
  actual chart graphics and arranging multiple-axes without collision as
  well as tying together all the event/signalling so that only a single
  "focussed" view relays to all overlays.
plotitem_overlays
Tyler Goodlet 2022-01-21 16:19:25 -05:00
parent 637c9c65e9
commit 4b89f7197a
1 changed files with 381 additions and 3 deletions
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384
piker/ui/_overlay.py
View File

@ -18,17 +18,27 @@
Charting overlay helpers.
'''
from typing import Callable, Optional
from pyqtgraph.Qt.QtCore import (
# QObject,
# Signal,
Qt,
# QEvent,
)
from pyqtgraph.graphicsItems.AxisItem import AxisItem
# from pyqtgraph.graphicsItems.ViewBox import ViewBox
from pyqtgraph.graphicsItems.ViewBox import ViewBox
from pyqtgraph.graphicsItems.GraphicsWidget import GraphicsWidget
from pyqtgraph.graphicsItems.PlotItem.PlotItem import PlotItem
from pyqtgraph.Qt.QtCore import QObject, Signal, QEvent
from pyqtgraph.Qt.QtWidgets import QGraphicsGridLayout, QGraphicsLinearLayout
from ._interaction import ChartView
__all__ = ["PlotItemOverlay"]
# Define the layout "position" indices as to be passed
# to a ``QtWidgets.QGraphicsGridlayout.addItem()`` call:
# https://doc.qt.io/qt-5/qgraphicsgridlayout.html#addItem
@ -166,7 +176,7 @@ class ComposedGridLayout:
'''
if index < 0:
raise ValueError(f'`insert()` only supports an index >= 0')
raise ValueError('`insert()` only supports an index >= 0')
# add plot's axes in sequence to the embedded linear layouts
# for each "side" thus avoiding graphics collisions.
@ -250,4 +260,372 @@ class ComposedGridLayout:
Remove item and restack all axes in list-order.
'''
raise NotImplemented
raise NotImplementedError
# Unimplemented features TODO:
# - 'A' (autobtn) should relay to all views
# - context menu single handler + relay?
# - layout unwind and re-pack for 'left' and 'top' axes
# - add labels to layout if detected in source ``PlotItem``
# UX nice-to-have TODO:
# - optional "focussed" view box support for view boxes
# that have custom input handlers (eg. you might want to
# scale the view to some "focussed" data view and have overlayed
# viewboxes only respond to relayed events.)
# - figure out how to deal with menu raise events for multi-viewboxes.
# (we might want to add a different menu which specs the name of the
# view box currently being handled?
# - allow selection of a particular view box by interacting with its
# axis?
# TODO: we might want to enabled some kind of manual flag to disable
# this method wrapping during type creation? As example a user could
# definitively decide **not** to enable broadcasting support by
# setting something like ``ViewBox.disable_relays = True``?
def mk_relay_method(
signame: str,
slot: Callable[
[ViewBox,
'QEvent',
Optional[AxisItem]],
None,
],
) -> Callable[
[
ViewBox,
# lol, there isn't really a generic type thanks
# to the rewrite of Qt's event system XD
'QEvent',
'Optional[AxisItem]',
'Optional[ViewBox]', # the ``relayed_from`` arg we provide
],
None,
]:
def maybe_broadcast(
vb: 'ViewBox',
ev: 'QEvent',
axis: 'Optional[int]' = None,
relayed_from: 'ViewBox' = None,
) -> None:
'''
(soon to be) Decorator which makes an event handler
"broadcastable" to overlayed ``GraphicsWidget``s.
Adds relay signals based on the decorated handler's name
and conducts a signal broadcast of the relay signal if there
are consumers registered.
'''
# When no relay source has been set just bypass all
# the broadcast machinery.
if vb.event_relay_source is None:
ev.accept()
return slot(
vb,
ev,
axis=axis,
)
if relayed_from:
assert axis is None
# this is a relayed event and should be ignored (so it does not
# halt/short circuit the graphicscene loop). Further the
# surrounding handler for this signal must be allowed to execute
# and get processed by **this consumer**.
print(f'{vb.name} rx relayed from {relayed_from.name}')
ev.ignore()
return slot(
vb,
ev,
axis=axis,
)
if axis is not None:
print(f'{vb.name} handling axis event:\n{str(ev)}')
ev.accept()
return slot(
vb,
ev,
axis=axis,
)
elif (
relayed_from is None
and vb.event_relay_source is vb # we are the broadcaster
and axis is None
):
# Broadcast case: this is a source event which will be
# relayed to attached consumers and accepted after all
# consumers complete their own handling followed by this
# routine's processing. Sequence is,
# - pre-relay to all consumers *first* - ``.emit()`` blocks
# until all downstream relay handlers have run.
# - run the source handler for **this** event and accept
# the event
# Access the "bound signal" that is created
# on the widget type as part of instantiation.
signal = getattr(vb, signame)
# print(f'{vb.name} emitting {signame}')
# TODO/NOTE: we could also just bypass a "relay" signal
# entirely and instead call the handlers manually in
# a loop? This probably is a lot simpler and also doesn't
# have any downside, and allows not touching target widget
# internals.
signal.emit(
ev,
axis,
# passing this demarks a broadcasted/relayed event
vb,
)
# accept event so no more relays are fired.
ev.accept()
# call underlying wrapped method with an extra
# ``relayed_from`` value to denote that this is a relayed
# event handling case.
return slot(
vb,
ev,
axis=axis,
)
return maybe_broadcast
# XXX: :( can't define signals **after** class compile time
# so this is not really useful.
# def mk_relay_signal(
# func,
# name: str = None,
# ) -> Signal:
# (
# args,
# varargs,
# varkw,
# defaults,
# kwonlyargs,
# kwonlydefaults,
# annotations
# ) = inspect.getfullargspec(func)
# # XXX: generate a relay signal with 1 extra
# # argument for a ``relayed_from`` kwarg. Since
# # ``'self'`` is already ignored by signals we just need
# # to count the arguments since we're adding only 1 (and
# # ``args`` will capture that).
# numargs = len(args + list(defaults))
# signal = Signal(*tuple(numargs * [object]))
# signame = name or func.__name__ + 'Relay'
# return signame, signal
def enable_relays(
widget: GraphicsWidget,
handler_names: list[str],
) -> list[Signal]:
'''
Method override helper which enables relay of a particular
``Signal`` from some chosen broadcaster widget to a set of
consumer widgets which should operate their event handlers normally
but instead of signals "relayed" from the broadcaster.
Mostly useful for overlaying widgets that handle user input
that you want to overlay graphically. The target ``widget`` type must
define ``QtCore.Signal``s each with a `'Relay'` suffix for each
name provided in ``handler_names: list[str]``.
'''
signals = []
for name in handler_names:
handler = getattr(widget, name)
signame = name + 'Relay'
# ensure the target widget defines a relay signal
relay = getattr(widget, signame)
widget.relays[signame] = name
signals.append(relay)
method = mk_relay_method(signame, handler)
setattr(widget, name, method)
return signals
enable_relays(
ChartView,
['wheelEvent', 'mouseDragEvent']
)
class PlotItemOverlay:
'''
A composite for managing overlaid ``PlotItem`` instances such that
you can make multiple graphics appear on the same graph with
separate (non-colliding) axes apply ``ViewBox`` signal broadcasting
such that all overlaid items respond to input simultaneously.
'''
def __init__(
self,
root_plotitem: PlotItem
) -> None:
self.root_plotitem: PlotItem = root_plotitem
vb = root_plotitem.vb
vb.event_relay_source = vb # TODO: maybe change name?
vb.setZValue(1000) # XXX: critical for scene layering/relaying
self.overlays: list[PlotItem] = []
from piker.ui._overlay import ComposedGridLayout
self.layout = ComposedGridLayout(
root_plotitem,
root_plotitem.layout,
)
self._relays: dict[str, Signal] = {}
def add_plotitem(
self,
plotitem: PlotItem,
index: Optional[int] = None,
# TODO: we could also put the ``ViewBox.XAxis``
# style enum here?
# (0,), # link x
# (1,), # link y
# (0, 1), # link both
link_axes: tuple[int] = (),
) -> None:
index = index or 0
root = self.root_plotitem
# layout: QGraphicsGridLayout = root.layout
self.overlays.insert(index, plotitem)
vb: ViewBox = plotitem.vb
# mark this consumer overlay as ready to expect relayed events
# from the root plotitem.
vb.event_relay_source = root.vb
# TODO: some sane way to allow menu event broadcast XD
# vb.setMenuEnabled(False)
# TODO: inside the `maybe_broadcast()` (soon to be) decorator
# we need have checks that consumers have been attached to
# these relay signals.
if link_axes != (0, 1):
# wire up relay signals
for relay_signal_name, handler_name in vb.relays.items():
# print(handler_name)
# XXX: Signal class attrs are bound after instantiation
# of the defining type, so we need to access that bound
# version here.
signal = getattr(root.vb, relay_signal_name)
handler = getattr(vb, handler_name)
signal.connect(handler)
# link dim-axes to root if requested by user.
# TODO: solve more-then-wanted scaled panning on click drag
# which seems to be due to broadcast. So we probably need to
# disable broadcast when axes are linked in a particular
# dimension?
for dim in link_axes:
# link x and y axes to new view box such that the top level
# viewbox propagates to the root (and whatever other
# plotitem overlays that have been added).
vb.linkView(dim, root.vb)
# make overlaid viewbox impossible to focus since the top
# level should handle all input and relay to overlays.
# NOTE: this was solved with the `setZValue()` above!
# TODO: we will probably want to add a "focus" api such that
# a new "top level" ``PlotItem`` can be selected dynamically
# (and presumably the axes dynamically sorted to match).
vb.setFlag(
vb.GraphicsItemFlag.ItemIsFocusable,
False
)
vb.setFocusPolicy(Qt.NoFocus)
# append-compose into the layout all axes from this plot
self.layout.insert(index, plotitem)
plotitem.setGeometry(root.vb.sceneBoundingRect())
def size_to_viewbox(vb: 'ViewBox'):
plotitem.setGeometry(vb.sceneBoundingRect())
root.vb.sigResized.connect(size_to_viewbox)
# ensure the overlayed view is redrawn on each cycle
root.scene().sigPrepareForPaint.connect(vb.prepareForPaint)
# focus state sanity
vb.clearFocus()
assert not vb.focusWidget()
root.vb.setFocus()
assert root.vb.focusWidget()
# XXX: do we need this? Why would you build then destroy?
def remove_plotitem(self, plotItem: PlotItem) -> None:
'''
Remove this ``PlotItem`` from the overlayed set making not shown
and unable to accept input.
'''
...
# TODO: i think this would be super hot B)
def focus_item(self, plotitem: PlotItem) -> PlotItem:
'''
Apply focus to a contained PlotItem thus making it the "top level"
item in the overlay able to accept peripheral's input from the user
and responsible for zoom and panning control via its ``ViewBox``.
'''
...
def get_axis(
self,
plot: PlotItem,
name: str,
) -> AxisItem:
'''
Retrieve the named axis for overlayed ``plot``.
'''
return self.layout.get_axis(plot, name)
# TODO: i guess we need this if you want to detach existing plots
# dynamically? XXX: untested as of now.
def _disconnect_all(
self,
plotitem: PlotItem,
) -> list[Signal]:
'''
Disconnects all signals related to this widget for the given chart.
'''
disconnected = []
for pi, sig in self._relays.items():
QObject.disconnect(sig)
disconnected.append(sig)
return disconnected