cv2小记——把鼠标当画笔

import os
import sys
import numpy as np
import cv2
from matplotlib import pyplot as plt

rawPath = os.path.abspath(__file__)
currentFile = os.path.basename(sys.argv[0])
dataPath = rawPath[:rawPath.find(currentFile)] + r'static\\'

def draw_circle(event, x, y, flags, param):
    """
    在图片上双击过的位置绘制一个圆圈
    :return:
    """
    # 查看支持的鼠标事件
    # events = [i for i in dir(cv2) if 'EVENT' in i]
    # print(events)

    if event == cv2.EVENT_LBUTTONDBLCLK:
        cv2.circle(img, (x, y), 100, (255, 255, 255), -1)


img = np.zeros((500, 500, 3), np.uint8)
cv2.namedWindow('image')
cv2.setMouseCallback('image', draw_circle)

while 1:
    cv2.imshow('image', img)
    if cv2.waitKey(20) == 27:
        break
cv2.destroyAllWindows()

# 当鼠标按下时变为 True
drawing = False
# 如果 mode 为 true 绘制矩形，按下 m 变成绘制曲线
mode = True
ix, iy = -1, -1


# 创建回调函数
def draw_circle(event,x, y, flags, param):
    global ix, iy, drawing, mode
    if event == cv2.EVENT_LBUTTONDOWN:
        drawing = True
        ix, iy = x, y
    elif event == cv2.EVENT_MOUSEMOVE and flags == cv2.EVENT_FLAG_LBUTTON:
        if drawing == True:
            if mode == True:
                cv2.rectangle(img, (ix, iy), (x, y), (0, 255, 0), -1)
            else:
                # 绘制圆圈
                cv2.circle(img, (x, y), 3, (0, 0, 255), -1)
                # 下面注释掉的代码是起始点为圆心，起点到终点为半径的
                # r = int(np.sqrt((x - ix)**2 + (y - iy)**2))
                # cv2.circle(img, (x, y), r, (0, 0, 255), -1)
    elif event == cv2.EVENT_LBUTTONUP:
        drawing = False
        if mode == True:
            cv2.rectangle(img, (ix, iy), (x, y), (0, 255, 0), -1)
        else:
            cv2.circle(img, (x, y), 5, (0, 0, 255), -1)


img = np.zeros((512, 512, 3), np.uint8)
cv2.namedWindow('image')
cv2.setMouseCallback('image', draw_circle)

while 1:
    cv2.imshow('image', img)
    k = cv2.waitKey(1)
    if k == ord('m'):
        mode = not mode
    elif k == 27:
        break