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Source code for matplotlib.blocking_input

"""
This provides several classes used for blocking interaction with figure
windows:

`BlockingInput`
    Creates a callable object to retrieve events in a blocking way for
    interactive sessions.  Base class of the other classes listed here.

`BlockingKeyMouseInput`
    Creates a callable object to retrieve key or mouse clicks in a blocking
    way for interactive sessions.  Used by `waitforbuttonpress`.

`BlockingMouseInput`
    Creates a callable object to retrieve mouse clicks in a blocking way for
    interactive sessions.  Used by `ginput`.

`BlockingContourLabeler`
    Creates a callable object to retrieve mouse clicks in a blocking way that
    will then be used to place labels on a `ContourSet`.  Used by `clabel`.
"""

import logging
from numbers import Integral

import matplotlib.lines as mlines

_log = logging.getLogger(__name__)


[docs]class BlockingInput(object): """Callable for retrieving events in a blocking way.""" def __init__(self, fig, eventslist=()): self.fig = fig self.eventslist = eventslist
[docs] def on_event(self, event): """ Event handler; will be passed to the current figure to retrieve events. """ # Add a new event to list - using a separate function is overkill for # the base class, but this is consistent with subclasses. self.add_event(event) _log.info("Event %i", len(self.events)) # This will extract info from events. self.post_event() # Check if we have enough events already. if len(self.events) >= self.n > 0: self.fig.canvas.stop_event_loop()
[docs] def post_event(self): """For baseclass, do nothing but collect events."""
[docs] def cleanup(self): """Disconnect all callbacks.""" for cb in self.callbacks: self.fig.canvas.mpl_disconnect(cb) self.callbacks = []
[docs] def add_event(self, event): """For base class, this just appends an event to events.""" self.events.append(event)
[docs] def pop_event(self, index=-1): """ Remove an event from the event list -- by default, the last. Note that this does not check that there are events, much like the normal pop method. If no events exist, this will throw an exception. """ self.events.pop(index)
pop = pop_event def __call__(self, n=1, timeout=30): """Blocking call to retrieve *n* events.""" if not isinstance(n, Integral): raise ValueError("Requires an integer argument") self.n = n self.events = [] if hasattr(self.fig.canvas, "manager"): # Ensure that the figure is shown, if we are managing it. self.fig.show() # Connect the events to the on_event function call. self.callbacks = [self.fig.canvas.mpl_connect(name, self.on_event) for name in self.eventslist] try: # Start event loop. self.fig.canvas.start_event_loop(timeout=timeout) finally: # Run even on exception like ctrl-c. # Disconnect the callbacks. self.cleanup() # Return the events in this case. return self.events
[docs]class BlockingMouseInput(BlockingInput): """ Callable for retrieving mouse clicks in a blocking way. This class will also retrieve keypresses and map them to mouse clicks: delete and backspace are like mouse button 3, enter is like mouse button 2 and all others are like mouse button 1. """ button_add = 1 button_pop = 3 button_stop = 2 def __init__(self, fig, mouse_add=1, mouse_pop=3, mouse_stop=2): BlockingInput.__init__(self, fig=fig, eventslist=('button_press_event', 'key_press_event')) self.button_add = mouse_add self.button_pop = mouse_pop self.button_stop = mouse_stop
[docs] def post_event(self): """Process an event.""" if len(self.events) == 0: _log.warning("No events yet") elif self.events[-1].name == 'key_press_event': self.key_event() else: self.mouse_event()
[docs] def mouse_event(self): """Process a mouse click event.""" event = self.events[-1] button = event.button if button == self.button_pop: self.mouse_event_pop(event) elif button == self.button_stop: self.mouse_event_stop(event) elif button == self.button_add: self.mouse_event_add(event)
[docs] def key_event(self): """ Process a key press event, mapping keys to appropriate mouse clicks. """ event = self.events[-1] if event.key is None: # At least in OSX gtk backend some keys return None. return key = event.key.lower() if key in ['backspace', 'delete']: self.mouse_event_pop(event) elif key in ['escape', 'enter']: self.mouse_event_stop(event) else: self.mouse_event_add(event)
[docs] def mouse_event_add(self, event): """ Process an button-1 event (add a click if inside axes). Parameters ---------- event : `~.backend_bases.MouseEvent` """ if event.inaxes: self.add_click(event) else: # If not a valid click, remove from event list. BlockingInput.pop(self)
[docs] def mouse_event_stop(self, event): """ Process an button-2 event (end blocking input). Parameters ---------- event : `~.backend_bases.MouseEvent` """ # Remove last event just for cleanliness. BlockingInput.pop(self) # This will exit even if not in infinite mode. This is consistent with # MATLAB and sometimes quite useful, but will require the user to test # how many points were actually returned before using data. self.fig.canvas.stop_event_loop()
[docs] def mouse_event_pop(self, event): """ Process an button-3 event (remove the last click). Parameters ---------- event : `~.backend_bases.MouseEvent` """ # Remove this last event. BlockingInput.pop(self) # Now remove any existing clicks if possible. if self.events: self.pop(event)
[docs] def add_click(self, event): """ Add the coordinates of an event to the list of clicks. Parameters ---------- event : `~.backend_bases.MouseEvent` """ self.clicks.append((event.xdata, event.ydata)) _log.info("input %i: %f, %f", len(self.clicks), event.xdata, event.ydata) # If desired, plot up click. if self.show_clicks: line = mlines.Line2D([event.xdata], [event.ydata], marker='+', color='r') event.inaxes.add_line(line) self.marks.append(line) self.fig.canvas.draw()
[docs] def pop_click(self, event, index=-1): """ Remove a click (by default, the last) from the list of clicks. Parameters ---------- event : `~.backend_bases.MouseEvent` """ self.clicks.pop(index) if self.show_clicks: self.marks.pop(index).remove() self.fig.canvas.draw()
[docs] def pop(self, event, index=-1): """ Removes a click and the associated event from the list of clicks. Defaults to the last click. """ self.pop_click(event, index) BlockingInput.pop(self, index)
[docs] def cleanup(self, event=None): """ Parameters ---------- event : `~.backend_bases.MouseEvent`, optional Not used """ # Clean the figure. if self.show_clicks: for mark in self.marks: mark.remove() self.marks = [] self.fig.canvas.draw() # Call base class to remove callbacks. BlockingInput.cleanup(self)
def __call__(self, n=1, timeout=30, show_clicks=True): """ Blocking call to retrieve *n* coordinate pairs through mouse clicks. """ self.show_clicks = show_clicks self.clicks = [] self.marks = [] BlockingInput.__call__(self, n=n, timeout=timeout) return self.clicks
[docs]class BlockingContourLabeler(BlockingMouseInput): """ Callable for retrieving mouse clicks and key presses in a blocking way. Used to place contour labels. """ def __init__(self, cs): self.cs = cs BlockingMouseInput.__init__(self, fig=cs.ax.figure)
[docs] def add_click(self, event): self.button1(event)
[docs] def pop_click(self, event, index=-1): self.button3(event)
[docs] def button1(self, event): """ Process an button-1 event (add a label to a contour). Parameters ---------- event : `~.backend_bases.MouseEvent` """ # Shorthand if event.inaxes == self.cs.ax: self.cs.add_label_near(event.x, event.y, self.inline, inline_spacing=self.inline_spacing, transform=False) self.fig.canvas.draw() else: # Remove event if not valid BlockingInput.pop(self)
[docs] def button3(self, event): """ Process an button-3 event (remove a label if not in inline mode). Unfortunately, if one is doing inline labels, then there is currently no way to fix the broken contour - once humpty-dumpty is broken, he can't be put back together. In inline mode, this does nothing. Parameters ---------- event : `~.backend_bases.MouseEvent` """ if self.inline: pass else: self.cs.pop_label() self.cs.ax.figure.canvas.draw()
def __call__(self, inline, inline_spacing=5, n=-1, timeout=-1): self.inline = inline self.inline_spacing = inline_spacing BlockingMouseInput.__call__(self, n=n, timeout=timeout, show_clicks=False)
[docs]class BlockingKeyMouseInput(BlockingInput): """ Callable for retrieving mouse clicks and key presses in a blocking way. """ def __init__(self, fig): BlockingInput.__init__(self, fig=fig, eventslist=( 'button_press_event', 'key_press_event'))
[docs] def post_event(self): """Determine if it is a key event.""" if self.events: self.keyormouse = self.events[-1].name == 'key_press_event' else: _log.warning("No events yet.")
def __call__(self, timeout=30): """ Blocking call to retrieve a single mouse click or key press. Returns ``True`` if key press, ``False`` if mouse click, or ``None`` if timed out. """ self.keyormouse = None BlockingInput.__call__(self, n=1, timeout=timeout) return self.keyormouse