OpenCV畫線圓橢圓多邊形和以鼠標爲畫筆——python實現

一、畫線、圓、橢圓、多邊形、文字

import numpy as np
import cv2

#先生成一個黑色圖片
img = np.zeros((512, 512, 3), np.uint8)
#畫一條線
cv2.line(img, (0,0),(511,511),(255,0,0),5)  #繪製一條對角線，從左上角到右下角，顏色是(255,0,0)藍色，線條粗細：5px，(5個像素寬度)
#畫矩形
cv2.rectangle(img,(384,0),(511,128),(0,255,0),5)
#畫圓
cv2.circle(img,(447,63), 63, (0,0,255),5)
#畫橢圓
cv2.ellipse(img,(256,256),(100,50),0,0,360,255,-1)
#繪製多邊形
pts = np.array([[1,2],[100,10],[100,100],[1,150]],np.int32)  #順時針畫線
pts = pts.reshape((-1,1,2)) #參數newshape = -1，表明這一維的長度是根據後面的維度計算出來的
cv2.polylines(img,[pts],True,(0,255,255))  #參數爲True，得到順次連接的閉合多邊形
#在圖片中繪製文字
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、以鼠標爲畫筆

import cv2
import numpy as np

drawing = False #鼠標按下後爲True
mode = True #如果爲True，畫矩形。按'm'鍵轉換爲畫圓
ix, iy = -1,-1

#鼠標回調函數
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()

切換到m