Making annotation for location of target in Image.

ann.py

import matplotlib.pyplot as plt
from matplotlib.widgets import Button
import numpy as np
import os

name = "IMG_9781"

fig, ax = plt.subplots(figsize=(12, 8), dpi=100)
plt.subplots_adjust(bottom=0, top=1, left=0, right=1)
plt.title(name)
img = plt.imread(name + ".JPG")
ann_filename = name + '.npz'
count = 0
circle_size = 5
ann = []


def Read():
    global ann
    if os.path.exists(ann_filename):
        print("Recover")
        ann = list(np.load(ann_filename)['ann'])
        print(ann)
    Load()


def Load():
    ax.clear()
    ax.imshow(img)
    ax.axis('off')
    for an in ann:
        plotCircle(an[0], an[1])
    plt.draw()


def plotCircle(x, y):
    circle1 = plt.Circle((x, y), circle_size, color='r')
    ax.add_artist(circle1)
    plt.draw()


print("""
Right click to redo
Left click to point
Middle click to save
Shift + any to do whatever you want(ex, enlarge)
""")


def onclick(event):
    print(event)
    """
    print('%s click: button=%d, x=%d, y=%d, xdata=%f, ydata=%f' %
          ('double' if event.dblclick else 'single', event.button,
           event.x, event.y, event.xdata, event.ydata))
    """
    if event.key:
        print(event.key)
        return
    if event.button == 3:
        print("Redo")
        ann.pop()
        Load()
    elif event.button == 2:
        print("Save")
        np.savez(ann_filename, ann=ann)
    else:
        print("Add")
        plotCircle(event.xdata, event.ydata)
        ann.append([event.xdata, event.ydata])


cid = fig.canvas.mpl_connect('button_press_event', onclick)

Read()
plt.show()