CODEWITHSUNDEEP
pythonmatplotlibonclicksubplot
memecs
memecs

Reputation: 7564

Determine button clicked subplot

Given a figure with multiple plots, is there a way to determine which of them was clicked with a mouse button?

E.g.

fig = plt.figure()

ax  = fig.add_subplot(121)
ax.imshow(imsp0)

ax = fig.add_subplot(122)
ax.imshow(imsp1)

fig.canvas.mpl_connect("button_press_event",onclick_select)

def onclick_select(event):
  ... do something depending on the clicked subplot

Upvotes: 6

Views: 4027

Answers (2)

ImportanceOfBeingErnest
ImportanceOfBeingErnest

Reputation: 339122

If you retain a handle to both axes, you may just query the axes in which the click has happened; e.g. if event.inaxes == ax:

import matplotlib.pyplot as plt
import numpy as np

imsp0 = np.random.rand(10,10)
imsp1 = np.random.rand(10,10)

fig = plt.figure()

ax  = fig.add_subplot(121)
ax.imshow(imsp0)

ax2 = fig.add_subplot(122)
ax2.imshow(imsp1)

def onclick_select(event):
    if event.inaxes == ax:
        print ("event in ax")
    elif event.inaxes == ax2:
        print ("event in ax2")

fig.canvas.mpl_connect("button_press_event",onclick_select)

plt.show()

Upvotes: 7

DrV
DrV

Reputation: 23490

It is possible at least by applying the following steps:

  • the onclick event has attributes x and y carrying the pixel coordinates from the corner of the figure

  • these coordinates can be converted into figure coordinates by using fig.transFigure.inverted().transform((x,y))

  • you can get the bounding box of each subplot by bb=ax.get_position()

  • iterate through all subplots (axes) of the image

  • you can test whether the click is within the area of this bounding box by bb.contains(fx,fy), where fx and fy are the button click coordinates transformed into image position

For more info on the onclick event: http://matplotlib.org/users/event_handling.html For more info on the coordinate transformations: http://matplotlib.org/users/transforms_tutorial.html

Upvotes: 2

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