OpenCV画线圆椭圆多边形和以鼠标为画笔——python实现

一、画线、圆、椭圆、多边形、文字

import numpy as np
import cv2

#先生成一个黑色图片
img = np.zeros((512, 512, 3), np.uint8)
#画一条线
cv2.line(img, (0,0),(511,511),(255,0,0),5)  #绘制一条对角线，从左上角到右下角，颜色是(255,0,0)蓝色，线条粗细：5px，(5个像素宽度)
#画矩形
cv2.rectangle(img,(384,0),(511,128),(0,255,0),5)
#画圆
cv2.circle(img,(447,63), 63, (0,0,255),5)
#画椭圆
cv2.ellipse(img,(256,256),(100,50),0,0,360,255,-1)
#绘制多边形
pts = np.array([[1,2],[100,10],[100,100],[1,150]],np.int32)  #顺时针画线
pts = pts.reshape((-1,1,2)) #参数newshape = -1，表明这一维的长度是根据后面的维度计算出来的
cv2.polylines(img,[pts],True,(0,255,255))  #参数为True，得到顺次连接的闭合多边形
#在图片中绘制文字
font = cv2.FONT_HERSHEY_SIMPLEX
cv2.putText(img,'FUCK',(10,500),font,2,(255,255,255),5)
cv2.imshow('line',img)
cv2.waitKey(0)
cv2.destroyAllWindows()

 

二、以鼠标为画笔

import cv2
import numpy as np

drawing = False #鼠标按下后为True
mode = True #如果为True，画矩形。按'm'键转换为画圆
ix, iy = -1,-1

#鼠标回调函数
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:
        if drawing == True:
            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)
    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) & 0xFF
    if k == ord('m'):
        mode = not mode
    elif k == 27:
        break
cv2.destroyAllWindows()

切换到m