绘制矩形或线条使用python打开cv使用鼠标事件

Question

我想绘制两个坐标之间的直线，这将通过单击图像或鼠标事件获得。我可以通过单击鼠标绘制各个圆圈，但无法弄清楚如何在这些点之间画线。当我使用这段代码时，我只能打印开始和结束坐标，而不是在它们之间划一条线。

import numpy as np 
import cv2 
import cv2.cv as cv 

boxes = [] 

def on_mouse(event, x, y, flags, params): 
    if event == cv.CV_EVENT_LBUTTONDOWN: 
     print 'Start Mouse Position: '+str(x)+', '+str(y) 
     sbox = [x, y] 
     boxes.append(sbox) 

    elif event == cv.CV_EVENT_LBUTTONUP: 
     print 'End Mouse Position: '+str(x)+', '+str(y) 
     ebox = [x, y] 
     boxes.append(ebox) 


count = 0 
while(1): 
    count += 1 
    img = cv2.imread('img.jpg',0) 
    img = cv2.blur(img, (3,3)) 

    cv2.namedWindow('real image') 
    cv.SetMouseCallback('real image', on_mouse, 0) 
    cv2.imshow('real image', img) 
    if count < 50: 
     if cv2.waitKey(33) == 27: 
      cv2.destroyAllWindows() 
      break 
    elif count >= 50: 
     if cv2.waitKey(0) == 27: 
      cv2.destroyAllWindows() 
      break 
     count = 0 

不知何故，我无法提取循环外的坐标。有人可以请建议如何画点线或矩形点之间的点我的形象？

Answer 1

您可以参考下面我用它来裁剪图像

#include <iostream> 
#include "opencv2/opencv.hpp" 
#include <stdio.h> 

using namespace std; 
using namespace cv; 


Mat src,img,ROI; 
Rect cropRect(0,0,0,0); 
Point P1(0,0); 
Point P2(0,0); 

const char* winName="Crop Image"; 
bool clicked=false; 
int i=0; 
char imgName[15]; 


void checkBoundary(){ 
     //check croping rectangle exceed image boundary 
     if(cropRect.width>img.cols-cropRect.x) 
     cropRect.width=img.cols-cropRect.x; 

     if(cropRect.height>img.rows-cropRect.y) 
     cropRect.height=img.rows-cropRect.y; 

     if(cropRect.x<0) 
     cropRect.x=0; 

     if(cropRect.y<0) 
     cropRect.height=0; 
} 

void showImage(){ 
    img=src.clone(); 
    checkBoundary(); 
    if(cropRect.width>0&&cropRect.height>0){ 
     ROI=src(cropRect); 
     imshow("cropped",ROI); 
    } 

    rectangle(img, cropRect, Scalar(0,255,0), 1, 8, 0); 
    imshow(winName,img); 
} 


void onMouse(int event, int x, int y, int f, void*){ 


    switch(event){ 

     case CV_EVENT_LBUTTONDOWN : 
             clicked=true; 

             P1.x=x; 
             P1.y=y; 
             P2.x=x; 
             P2.y=y; 
             break; 

     case CV_EVENT_LBUTTONUP : 
             P2.x=x; 
             P2.y=y; 
             clicked=false; 
             break; 

     case CV_EVENT_MOUSEMOVE : 
             if(clicked){ 
             P2.x=x; 
             P2.y=y; 
             } 
             break; 

     default      : break; 


    } 


    if(clicked){ 
    if(P1.x>P2.x){ cropRect.x=P2.x; 
         cropRect.width=P1.x-P2.x; } 
     else {   cropRect.x=P1.x; 
         cropRect.width=P2.x-P1.x; } 

     if(P1.y>P2.y){ cropRect.y=P2.y; 
         cropRect.height=P1.y-P2.y; } 
     else {   cropRect.y=P1.y; 
         cropRect.height=P2.y-P1.y; } 

    } 


showImage(); 


} 
int main() 
{ 

    cout<<"Click and drag for Selection"<<endl<<endl; 
    cout<<"------> Press 's' to save"<<endl<<endl; 

    cout<<"------> Press '8' to move up"<<endl; 
    cout<<"------> Press '2' to move down"<<endl; 
    cout<<"------> Press '6' to move right"<<endl; 
    cout<<"------> Press '4' to move left"<<endl<<endl; 

    cout<<"------> Press 'w' increas top"<<endl; 
    cout<<"------> Press 'x' increas bottom"<<endl; 
    cout<<"------> Press 'd' increas right"<<endl; 
    cout<<"------> Press 'a' increas left"<<endl<<endl; 

    cout<<"------> Press 't' decrease top"<<endl; 
    cout<<"------> Press 'b' decrease bottom"<<endl; 
    cout<<"------> Press 'h' decrease right"<<endl; 
    cout<<"------> Press 'f' decrease left"<<endl<<endl; 

    cout<<"------> Press 'r' to reset"<<endl; 
    cout<<"------> Press 'Esc' to quit"<<endl<<endl; 


    src=imread("src.png",1); 

    namedWindow(winName,WINDOW_NORMAL); 
    setMouseCallback(winName,onMouse,NULL); 
    imshow(winName,src); 

    while(1){ 
    char c=waitKey(); 
    if(c=='s'&&ROI.data){ 
    sprintf(imgName,"%d.jpg",i++); 
    imwrite(imgName,ROI); 
    cout<<" Saved "<<imgName<<endl; 
    } 
    if(c=='6') cropRect.x++; 
    if(c=='4') cropRect.x--; 
    if(c=='8') cropRect.y--; 
    if(c=='2') cropRect.y++; 

    if(c=='w') { cropRect.y--; cropRect.height++;} 
    if(c=='d') cropRect.width++; 
    if(c=='x') cropRect.height++; 
    if(c=='a') { cropRect.x--; cropRect.width++;} 

    if(c=='t') { cropRect.y++; cropRect.height--;} 
    if(c=='h') cropRect.width--; 
    if(c=='b') cropRect.height--; 
    if(c=='f') { cropRect.x++; cropRect.width--;} 

    if(c==27) break; 
    if(c=='r') {cropRect.x=0;cropRect.y=0;cropRect.width=0;cropRect.height=0;} 
    showImage(); 

    } 


    return 0; 
} 

Answer 2

这里的C++代码是一个Python实现

import cv2 
    import cv2.cv as cv 
    from time import time 
    boxes = [] 
    def on_mouse(event, x, y, flags, params): 
     # global img 
     t = time() 

     if event == cv.CV_EVENT_LBUTTONDOWN: 
      print 'Start Mouse Position: '+str(x)+', '+str(y) 
      sbox = [x, y] 
      boxes.append(sbox) 
      # print count 
      # print sbox 

     elif event == cv.CV_EVENT_LBUTTONUP: 
      print 'End Mouse Position: '+str(x)+', '+str(y) 
      ebox = [x, y] 
      boxes.append(ebox) 
      print boxes 
      crop = img[boxes[-2][1]:boxes[-1][1],boxes[-2][0]:boxes[-1][0]] 

      cv2.imshow('crop',crop) 
      k = cv2.waitKey(0) 
      if ord('r')== k: 
       cv2.imwrite('Crop'+str(t)+'.jpg',crop) 
       print "Written to file" 

    count = 0 
    while(1): 
     count += 1 
     img = cv2.imread('path.img',0) 
     # img = cv2.blur(img, (3,3)) 
     img = cv2.resize(img, None, fx = 0.25,fy = 0.25) 

     cv2.namedWindow('real image') 
     cv.SetMouseCallback('real image', on_mouse, 0) 
     cv2.imshow('real image', img) 
     if count < 50: 
      if cv2.waitKey(33) == 27: 
       cv2.destroyAllWindows() 
       break 
     elif count >= 50: 
      if cv2.waitKey(0) == 27: 
       cv2.destroyAllWindows() 
       break 
      count = 0