C++ 从一幅图片上裁取需要的区域

1、Mat

Mat src, image_src;					//原图	
Mat imageROI;						//ROI区域
Mat TempImg;						//裁取出的区域存储为Mat
int x_begin, y_begin, width, height;		//裁取区域的坐标及大小
int srcWidth, srcHeight;					//存储原图宽、高
 //赋初值
x_begin = 0;  
y_begin = 0;
width = 100;
height = 100;
//读取原图
src = imread("test.jpg", 1);	
if(!src.data){
	cout<<" image read error!"<<endl;
	return -1; 
}
srcWidth = src.cols;	//获取原图宽、高
srcHeight = src.rows;
//控制裁取区域不超过原图
if(width < 1 || height < 1 || width > srcWidth || height > srcHeight){
	LOOGE<<"[Rect error: srcWidth = "<<srcWidth<<", srcHeight = "<<srcHeight<<", x_begin = "
			<<x_begin<<", y_begin = "<<y_begin<<", width = "<<width<<", height = "<<height<<" ]";
	return -1;
}
if(x_begin + width > srcWidth)		
	width = srcWidth - x_begin;
if(y_begin + height > srcHeight)
	height = srcHeight - y_begin;
2、IplImage
int x_begin, y_begin, width, height;			//裁取区域的坐标及大小
int srcWidth, srcHeight;						//原图宽、高
//赋初值
x_begin = 0; 
y_begin = 0;
width = 100;
height = 100;
//读取原图
IplImage* src = cvLoadImage("test.jpg", 1);
if(!src){
	cout<<" image read error!"<<endl;
	cvReleaseImage(&src);
	return -1;
 }
srcWidth = image->width;	//获取原图宽、高
srcHeight = image->height;
//控制裁取区域不超过原图
if(width < 1 || height < 1 || width > srcWidth || height > srcHeight){
	LOOGE<<"[Rect error: srcWidth = "<<srcWidth<<", srcHeight = "<<srcHeight<<", x_begin = "
		<<x_begin<<", y_begin = "<<y_begin<<", width = "<<width<<", height = "<<height<<" ]";
	cvReleaseImage(&src);
	return -1;
}
if(x_begin + width > srcWidth) 
	width = srcWidth - x_begin;
if(y_begin + height > srcHeight)
	height = srcHeight - y_begin;
//区域裁取
IplImage* image_src = cvCloneImage(src);	//备份原图
cvSetImageROI(image_src, cvRect(x_begin, y_begin, width, height));	//设置待裁取ROI
IplImage* dst = cvCreateImage(cvSize(width, height), src->depth, src->nChannels);	//创建裁取区域大小的IplImage*
cvCopy(image_src, dst);		//将ROI区域拷贝至dst
//释放资源
cvReleaseImage(&src);
cvResetImageROI(image_src);
cvReleaseImage(&image_src);
//区域裁取
image_src = src.clone();			//备份原图
imageROI = image_src(Rect(x_begin, y_begin, width, height));	//设置待裁取ROI
imageROI.convertTo(TempImg, TempImg.type());		//将ROI区域拷贝至ds