Matplotlib.pyplot.connect() in Python (original) (raw)

Last Updated : 03 May, 2020

Matplotlib is a library in Python and it is numerical - mathematical extension for NumPy library. Pyplot is a state-based interface to a Matplotlib module which provides a MATLAB-like interface.

matplotlib.pyplot.connect() Function

This method is used to connect an event with string s to a function.

Syntax: matplotlib.pyplot.connect(s, func)Parameters: This method accept the following parameters that are described below:s(str): One of the following events ids: 1. 'button_press_event' 2. 'button_release_event' 3. 'draw_event' 4. 'key_press_event' 5. 'key_release_event' 6. 'motion_notify_event' 7. 'pick_event' 8. 'resize_event' 9. 'scroll_event' 10. 'figure_enter_event', 11. 'figure_leave_event', 12. 'axes_enter_event', 13. 'axes_leave_event' 14. 'close_event'.func(callable): The callback function to be executed, which must have the signature: def func(event: Event) -> AnyReturns(cid): A connection id that can be used with FigureCanvasBase.mpl_disconnect.

Example 1 :

Python3 1== `

matplotlib.pyplot.connect()

from matplotlib.backend_bases import MouseButton import matplotlib.pyplot as plt import numpy as np

t = np.arange(0.0, 1.0, 0.01) s = np.sin(2 * np.pi * t) fig, ax = plt.subplots() ax.plot(t, s)

def on_move(event):

# get the x and y pixel coords
x, y = event.x, event.y

if event.inaxes:
    ax = event.inaxes  # the axes instance
    print('data coords % f % f' % (event.xdata,
                                   event.ydata))

def on_click(event):

if event.button is MouseButton.LEFT:
    print('disconnecting callback')
    plt.disconnect(binding_id)

binding_id = plt.connect('motion_notify_event', on_move)

plt.connect('button_press_event', on_click)

plt.show()

`

Output : python-matplotlib-callback Example 2 :

Python3 1== `

from matplotlib.widgets import RectangleSelector import numpy as np import matplotlib.pyplot as plt

def line_select_callback(eclick, erelease):

# Callback for line selection.
# *eclick * and * erelease *
# are the press and release events.
x1, y1 = eclick.xdata, eclick.ydata
x2, y2 = erelease.xdata, erelease.ydata
print("(% 3.2f, % 3.2f) --> (% 3.2f, % 3.2f)" % (x1, y1, x2, y2))
print(" The button you used were: % s % s" % (eclick.button, 
                                              erelease.button))

def toggle_selector(event):

print(' Key pressed.')

if event.key in ['Q', 'q'] and toggle_selector.RS.active:
    print(' RectangleSelector deactivated.')
    toggle_selector.RS.set_active(False)
    print(' RectangleSelector activated.')
    toggle_selector.RS.set_active(True)

make a new plotting range

fig, current_ax = plt.subplots()

If N is large one can see

N = 100000

improvement by use blitting !

plt.plot(x, +np.sin(.2 * np.pi * x),

lw = 3.5, c ='b', alpha =.7)

plot something

x = np.linspace(0.0, 10.0, N) plt.plot(x, +np.cos(.2 * np.pi * x), lw = 3.5, c ='c', alpha =.5) plt.plot(x, -np.sin(.2 * np.pi * x), lw = 3.5, c ='r', alpha =.3)

print("\n click --> release")

drawtype is 'box' or 'line' or 'none'

toggle_selector.RS = RectangleSelector(current_ax, line_select_callback, drawtype ='box', useblit = True, button =[1, 3], # don't use middle button minspanx = 5, minspany = 5, spancoords ='pixels', interactive = True)

plt.connect('key_press_event', toggle_selector) plt.show()

`

Output : python-matplotlib-connect-2 python-matplotlib-connect-3

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