Python中使用cv2库实现绘制动态圆和矩形的方法
本文可以实现在指定图片上动态绘制圆和矩形。
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()
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