圖像處理筆記（5）---- OpenCV 用滑動條做調色闆

建立一個畫闆，可以自選各種顔色來繪制各種圖形。

import numpy as np
import cv2 as cv

def nothing(x):
    pass


drawing = False #如果按下滑鼠，則為真
mode = True #如果為真，繪制矩形。按m鍵可以切換到曲線
ix,iy = -1,-1
#滑鼠回調函數
def draw_circle(event, x, y, flags, param):
    r = cv.getTrackbarPos('R','image')
    g = cv.getTrackbarPos('G','image')
    b = cv.getTrackbarPos('B','image')
    color = (b,g,r)
    
    global ix,iy,drawing,mode
    if event == cv.EVENT_LBUTTONDOWN:
        drawing = True
        ix,iy = x,y
    #當滑鼠左鍵按下并移動是繪制圖形。event可以檢視移動，flags檢視是否按下
    elif event == cv.EVENT_MOUSEMOVE and flags == cv.EVENT_FLAG_LBUTTON:
        if drawing == True:
            if mode == True:
                cv.rectangle(img, (ix,iy), (x,y), color, -1)
            else:
                r = int(np.sqrt((x - ix)**2 + (y - iy)**2))
                cv.circle(img,(x,y), r, color, -1)
    #當滑鼠松開停止繪畫      
    elif event == cv.EVENT_LBUTTONUP:
        drawing = False
        if mode == True:
            cv.rectangle(img, (ix,iy),(x,y),color,-1)
        else:
            cv.circle(img,(x,y),abs(x-ix),color,-1)


        
#建立一副黑色圖像
img = np.zeros((512,512,3),np.uint8)
cv.namedWindow('image')

cv.createTrackbar('R','image',0,255,nothing)
cv.createTrackbar('G','image',0,255,nothing)
cv.createTrackbar('B','image',0,255,nothing)
cv.setMouseCallback('image', draw_circle)

while(1):
    cv.imshow('image', img)
    if cv.waitKey(1) & 0xFF == 27:
        break
    elif cv.waitKey(1) & 0xFF == ord('m'):
        mode = not mode
        
cv.destroyAllWindows()           

複制

當一枚小畫家~