ShiftParameter.py

import cv2
import numpy as np
import matplotlib.pyplot as plt

def ShowWithMatplotlib(img, title):
    imgRGB=img[:, :, ::-1]
    plt.imshow(imgRGB)
    plt.title(title)
    plt.show()

def DrawFloatCircle(img, center, radius, color, thickness=1, lineType=8, shift=4):
    factor=2**shift
    center=(int(round(center[0]*factor)), int(round(center[1]*factor)))
    radius=int(round(radius*factor))
    cv2.circle(img, center, radius, color, thickness, lineType, shift)

colors={'blue':(255, 0, 0), 'green':(0, 255, 0), 'red':(0, 0, 255), 'yellow':(0, 255, 255),
        'magenta':(255, 0, 255), 'cyan':(255, 255, 0), 'white':(255, 255, 255), 'black':(0, 0, 0),
        'gray':(125, 125, 125), 'rand':np.random.randint(0, high=256, size=(3,)).tolist(),
        'dark_gray':(50, 50, 50), 'light_gray':(220, 220, 220)}

image=np.zeros((800, 800, 3), dtype="uint8")
image[:]=colors['light_gray']
DrawFloatCircle(image, (299, 299), 300, colors['red'], 1, 8, 0)
DrawFloatCircle(image, (299.9, 299.9), 300, colors['green'], 1, 8, 1)
DrawFloatCircle(image, (299.99, 299.99), 300, colors['blue'], 1, 8, 2)
DrawFloatCircle(image, (299.999, 299.999), 300, colors['yellow'], 1, 8, 3)
ShowWithMatplotlib(image, 'cv2.circle()')