02-event_filter.py 文件源码

def on_button(self, event):
        # only consider events from the lines Axes
        if event.inaxes is not self.ln.axes:
            return

        # if not the left mouse button or a modifier key
        # is held down, bail
        if event.button != 1 or event.key not in (None, 'shift'):
            print('key+button: {!r}+{!r}'.format(event.key, event.button))
            return

        if event.key == 'shift':
            # compute the distance to each point *in data space*
            d = np.hypot(np.asarray(self.xdata) - event.xdata,
                         np.asarray(self.ydata) - event.ydata)
            # find the closest point
            ix = np.argmin(d)
            # remove that data point
            del self.xdata[ix]
            del self.ydata[ix]
        else:
            # get the event location in data-space
            # and add to internal data list
            self.xdata.append(event.xdata)
            self.ydata.append(event.ydata)
        # update the line
        self._update_line()