Python中使用cv2库实现绘制动态圆和矩形的方法

import cv2

import numpy as np

import copy

class Rect(object):

    #创建一个类用于接收鼠标点击产生的数据坐标点。

    def __init__(self):

        self.t1 = (0,0)

        self.br = (0,0)

        self.r = 0

    def regularize(self):

        pt1 = (min(self.t1[0],self.br[0]),min(self.t1[1],self.br[1]))

        br1 = (max(self.t1[0],self.br[0]),max(self.t1[1],self.br[1]))

        self.t1 = pt1

        self.br = br1

class DrawRects(object):

    def __init__(self,img,color = (0,255,0),thickness = 3):

        self.img = img

        self.image_for_show = img.copy()

        '''

        用于覆盖之前的图片，然后在新的空白图片上将以前绘制的图片和目前最新的图片

        绘制的到新的图片上。

        '''

        self.color = color

        self.thickness = thickness

        self.left_button_down = False #用于判断左键是否按下。

        self.current_rect = Rect() #用于接收最新绘制的图形。

        self.rects = [] #用于接收绘制的矩形数据。

        self.circles = [] #用于接收绘制的圆数据

    @staticmethod

    def __clip(value,low,high):

        output = max(value,low)

        output = min(output,high)

        return output

    def shrink_point(self,x,y):

        height,width = self.image_for_show.shape[0:2]

        x_shrink = self.__clip(x,0,width)

        y_shrink = self.__clip(y,0,height)

        return (x_shrink,y_shrink)

    '''

    上述方法用于限制鼠标点击产生的数据在图片范围内。

    '''

    def reset_image(self):

        self.image_for_show = self.img.copy()

    def append(self):

        if draw_circle_now:

            self.rects.append(['c',copy.deepcopy(self.current_rect)])

        else:

            self.rects.append(['r',copy.deepcopy(self.current_rect)])

    def draw(self):

        for rect in self.rects:

            if rect[0] == 'r':

                cv2.rectangle(self.image_for_show,rect[1].t1,rect[1].br,color = self.color,thickness=self.thickness)

            elif rect[0] == 'c':

                cv2.circle(self.image_for_show,rect[1].t1,rect[1].r,color = self.color,thickness = self.thickness)

    def cal_R(self):

        self.current_rect.r = int((abs(self.current_rect.br[0] - self.current_rect.t1[0])**2 + abs(self.current_rect.br[1] - self.current_rect.t1[1])**2)**0.5)

        #print(self.current_circle.r)

        return self.current_rect.r

    def draw_current_rect(self):

        if draw_circle_now:

            self.current_rect.r = self.cal_R()

            cv2.circle(self.image_for_show,self.current_rect.t1,self.current_rect.r,color = self.color,thickness=3)

        else:

            cv2.rectangle(self.image_for_show,self.current_rect.t1,self.current_rect.br,

                      color = self.color,thickness = self.thickness)

    def pop(self):

        rect = Rect()

        if self.rects:

            rect = self.rects.pop()

        return rect

def onmouse_draw_rect(event,x,y,flags,draw_rects):

    if event == cv2.EVENT_LBUTTONDOWN:

        draw_rects.left_button_down = True

        draw_rects.current_rect.t1 = (x,y)

    if draw_rects.left_button_down  and event == cv2.EVENT_MOUSEMOVE:

        draw_rects.current_rect.br = draw_rects.shrink_point(x,y)

        draw_rects.reset_image()

        draw_rects.draw()

        draw_rects.draw_current_rect()

    if event == cv2.EVENT_LBUTTONUP:

        draw_rects.left_button_down = False

        draw_rects.current_rect.br = draw_rects.shrink_point(x,y)

        #draw_rects.current_rect.regularize()

        draw_rects.append()

    if (not draw_rects.left_button_down) and  event == cv2.EVENT_RBUTTONDOWN:

        draw_rects.pop()

        draw_rects.reset_image()

        draw_rects.draw()

draw_circle_now = False

img = np.zeros((516,516,3),np.uint8)

draw_rects = DrawRects(img,(0,255,255))

cv2.namedWindow('image')

cv2.setMouseCallback('image',onmouse_draw_rect,draw_rects)

while True:

    cv2.imshow('image',draw_rects.image_for_show)

    key = cv2.waitKey(30)

    if key == ord('c'):

        draw_circle_now = not draw_circle_now

    elif key == 27:

        break

cv2.destroyAllWindows()