单击外部绘图范围时，如何使matplotlib注释消失？

Question

I'm using the DataCursor code from unutbu to show annotations on a matplotlib figure when I click on a data point. (I can't find the link to this for the life of me, and the one I used to cite in my code doesn't point to the right place...) The problem is, I want them to go away when I click outside the plot.

def fmt(x, xlabel, y, ylabel)
    return xlabel+': {x:0.0f}\n'.format(x = x)+ylabel+': {y:0.3f}'.format(y = y)

class DataCursor(object):
    """A data cursor widget that displays the x,y of a matplotlib artist/plot when it is selected"""

    def annotate(self, ax)
        """ Draws and hides the annotations box for the given axis "ax". """
        annotation = ax.annotate(self.formatter, xy = (0,0), ha = 'right',
                                 xytext = self.offsets, textcoords = 'offset points', va = 'bottom',
                                 bbox = dict(boxstyle = 'round,pad=0.5', fc = 'yellow', alpha = 0.5),
                                 arrowprops = dict(arrowstyle = '->', connectionstyle = 'arc3,rad=0'))
        annotation.set_visible(False)
        return annotation

    def __init__(self, artists, x, xlabel, y, ylabel, tolerance = 5, offsets = (-20,20), formatter = fmt, display_all = False):
        """Create the data cursor and connect it to the relevant figure.
        "artists" is the matplotlib artist or sequence of artists that will be selected.
        "tolerance" is the radius (in points) that the mouse click must be within to select the artist.
        "offsets" is a tuple of (x,y) offsets in points from the selected point to the displayed annotation box.
        "formatter" is a callback function which takes 2 numeric arguments and returns a string.
        "display_all" controls whether more than one annotation box will be shown if there are multiple axes. Only one will be shown per axis, regardless.
        """

        self._points = np.column_stack((x,y))
        self.xlabel = xlabel
        self.ylabel = ylabel

        self.formatter = formatter
        self.offsets = offsets
        self.display_all = display_all

        if not cbook.iterable(artists):
            artists = [artists]

        self.artists = artists
        self.axes = tuple(set(art.axes for art in self.artists))
        self.figures = tuple(set(ax.figure for ax in self.axes))

        self.annotations = {}
        for ax in self.axes:
            self.annotations[ax] = self.annotate(ax)

        for artist in self.artists:
            artist.set_picker(tolerance)

        for fig in self.figures:
            fig.canvas.mpl_connect('pick_event', self)


    def snap(self, x, y):
        """ Return the value of in self._points closest to (x,y). """
        values = self.points
        idx = np.nanargmin(((values - (x,y))**2).sum(axis = -1)
        return self._points[idx,:]


    def __call__(self, event):
        """ Intended to be called through "mpl_connect" above. """
        x, y = event.mouseevent.xdata, event.mouseevent.ydata
        annotation = self.annotations[event.artist.axes]

        if x is None:
            for ann in self.annotations.values():
                ann.set_visible(False)
                event.canvas.draw()

        if x is not None:
            if not self.display_all:
                for ann in self.annotations.values():
                    ann.set_visible(False)

            x, y = self.snap(x, y)

            annotation.xy = x, y
            annotation.set_text(self.formatter(x, self.xlabel, y, self.ylabel))
            annotation.set_visible(True)
            annotation.draggable(True)
            event.canvas.draw()

According to documentation, I could use a function in artist.set_picker(tolerance) instead of tolerance . How does this work? The documentation doesn't do a great job of explaining this, and I'm having trouble finding examples.

The way the code works now, it will make the annotation disappear if I click outside the box, but within tolerance of a data point. This leaves me out of luck if there is no data within tolerance of the edge. How can I make it so that if I click anywhere in the gray area of the plot the annotation will disappear?

The code that I though would make it disappear:

    def __call__(self, event):
        """ Intended to be called through "mpl_connect" above. """
        x, y = event.mouseevent.xdata, event.mouseevent.ydata
        annotation = self.annotations[event.artist.axes]

        if x is None:
            for ann in self.annotations.values():
                ann.set_visible(False)
                event.canvas.draw()

Answer 1

Your problem is that your event-handling function only listens to 'pick_event' which are inherently associated with an artist (AFAIK).

To achieve what you want, you should add another listener that handles 'button_press_event'

This is untested code, but it should give you an idea:

# in the __init__ code, add:
fig.canvas.mpl_connect('button_press_event', self.clearAnn)

# in the class body:
def clearAnn(self, event):
    if event.inaxes is None:  # event.inaxes returns None if you click outside of the plot area, i.e. in the grey part surrounding the axes
        for ann in self.annotations.values():
            ann.set_visible(False)
            event.canvas.draw()