OpenCV中的照片剪裁

	Mat dstPic,srcPic;
	...
	dstPic = srcPic(Rect(x,y,width,height));
	...
	//参数x/y/width/height代表裁剪出来要保留的画面

#include <iostream>
#include "opencv2/core.hpp"
#include "opencv2/imgproc.hpp"
#include "opencv2/highgui.hpp"

using namespace std;
using namespace cv;

Mat org,dst,img,tmp;
double dScale;
const int startWidth=1280;

void showPicInScale(const char *wndName,Mat &pic,double scale){
	Size outSize;
	Mat displayPic;

	outSize.width=pic.cols * scale;
	outSize.height=pic.rows * scale;
	resize(pic,displayPic,outSize,0,0,INTER_AREA);
	imshow(wndName,displayPic);
	return;
}

void on_mouse(int event,int x1,int y1,int flags,void *ustc)//event鼠标事件代号，x,y鼠标坐标，flags拖拽和键盘操作的代号
{
	static Point pre_pt = Point(-1,-1);//初始坐标
	static Point cur_pt = Point(-1,-1);//实时坐标
	char temp[16];
	int x = x1 / dScale;
	int y = y1 / dScale;
	double fontSize=0.5 / dScale;
	int lineSize= 1 / dScale;
	//printf("fontsize:%d linesize:%d\n",fontSize,lineSize);
	if (event == CV_EVENT_LBUTTONDOWN)//左键按下，读取初始坐标，并在图像上该点处划圆
	{
		org.copyTo(img);//将原始图片复制到img中
		sprintf(temp,"(%d,%d)",x,y);
		pre_pt = Point(x,y);
		putText(img,temp,pre_pt,FONT_HERSHEY_SIMPLEX,fontSize,Scalar(0,0,0,255),lineSize,8);//在窗口上显示坐标
		circle(img,pre_pt,2/dScale,Scalar(255,0,0,0),CV_FILLED,CV_AA,0);//划圆
		showPicInScale("org",img,dScale);
	}
	else if (event == CV_EVENT_MOUSEMOVE && !(flags & CV_EVENT_FLAG_LBUTTON))//左键没有按下的情况下鼠标移动的处理函数
	{
		img.copyTo(tmp);//将img复制到临时图像tmp上，用于显示实时坐标
		sprintf(temp,"(%d,%d)",x,y);
		cur_pt = Point(x,y);
		putText(tmp,temp,cur_pt,FONT_HERSHEY_SIMPLEX,fontSize,Scalar(0,0,0,255),lineSize,8);//只是实时显示鼠标移动的坐标
		showPicInScale("org",tmp,dScale);
	}
	else if (event == CV_EVENT_MOUSEMOVE && (flags & CV_EVENT_FLAG_LBUTTON))//左键按下时，鼠标移动，则在图像上划矩形
	{
		img.copyTo(tmp);
		sprintf(temp,"(%d,%d)",x,y);
		cur_pt = Point(x,y);
		putText(tmp,temp,cur_pt,FONT_HERSHEY_SIMPLEX,fontSize,Scalar(0,0,0,255),lineSize,8);
		rectangle(tmp,pre_pt,cur_pt,Scalar(0,255,0,0),lineSize,8,0);//在临时图像上实时显示鼠标拖动时形成的矩形
		showPicInScale("org",tmp,dScale);
	}
	else if (event == CV_EVENT_LBUTTONUP)//左键松开，将在图像上划矩形
	{
		org.copyTo(img);
		sprintf(temp,"(%d,%d)",x,y);
		cur_pt = Point(x,y);
		putText(img,temp,cur_pt,FONT_HERSHEY_SIMPLEX,fontSize,Scalar(0,0,0,255),lineSize,8);
		circle(img,pre_pt,2/dScale,Scalar(255,0,0,0),CV_FILLED,CV_AA,0);
		rectangle(img,pre_pt,cur_pt,Scalar(0,255,0,0),lineSize,8,0);//根据初始点和结束点，将矩形画到img上
		showPicInScale("org",img,dScale);
		img.copyTo(tmp);
		//截取矩形包围的图像，并保存到dst中
		int width = abs(pre_pt.x - cur_pt.x);
		int height = abs(pre_pt.y - cur_pt.y);
		if (width == 0 || height == 0){
			return;
		}
		dst = org(Rect(min(cur_pt.x,pre_pt.x),min(cur_pt.y,pre_pt.y),width,height));
		imshow("cuted pic",dst);
	}
}

int setWindowTop(){
	namedWindow("GetFocus", CV_WINDOW_NORMAL);
	Mat img = cv::Mat::zeros(100, 100, CV_8UC3);
	imshow("GetFocus", img);
	setWindowProperty("GetFocus", CV_WND_PROP_FULLSCREEN, CV_WINDOW_FULLSCREEN);
	waitKey(1);
	setWindowProperty("GetFocus", CV_WND_PROP_FULLSCREEN, CV_WINDOW_NORMAL);
	destroyWindow("GetFocus");
	return 0;
}
int main(int argc,char **argv){
	int nQuit=1;
	
	if (argc != 2) {
		printf("%s imgfile",argv[0]);
	}
	org = imread(argv[1]);
	org.copyTo(img);
	dScale = (double)startWidth/org.cols;

	setWindowTop();
	//namedWindow("org",CV_WINDOW_NORMAL);//定义一个img窗口
	namedWindow("org");//定义一个img窗口
	setMouseCallback("org",on_mouse,0);//调用回调函数
	showPicInScale("org",img,dScale);

	double dZoomFactor=0.05;
	do {
		int key=waitKey(0);
		switch(key){
			case 27:
				nQuit=0;
				break;
			case 'q':
				dScale += 2*dZoomFactor;
			case 'a':
				dScale -= dZoomFactor;
				if (dScale <= 0)
					dScale = dZoomFactor;
				showPicInScale("org",img,dScale);
				break;
			default: continue;
		}
	} while (nQuit);
	
	return 0;
}