opencv 任意图形截取

转自：http://blog.csdn.net/wuxiaoyao12/article/details/7305865

得到任意形状区域

第一步、在图片上画出来

#include "cv.h"
#include "highgui.h"
#include <stdio.h>
#include <stdlib.h>

IplImage* inpaint_mask = 0;
IplImage* img0 = 0, *img = 0, *inpainted = 0;
CvPoint prev_pt = {-1,-1};

void on_mouse( int event, int x, int y, int flags, void* zhang)
{
if( !img )
return;
if( event == CV_EVENT_LBUTTONUP || !(flags & CV_EVENT_FLAG_LBUTTON) )
prev_pt = cvPoint(-1,-1);//初始化
else if( event == CV_EVENT_LBUTTONDOWN )
prev_pt = cvPoint(x,y);
else if( event == CV_EVENT_MOUSEMOVE && (flags & CV_EVENT_FLAG_LBUTTON) )
{//手一直在绘画
CvPoint pt = cvPoint(x,y);
if( prev_pt.x < 0 )
prev_pt = pt;
cvLine( inpaint_mask, prev_pt, pt, cvScalarAll(255), 5, 8, 0 );
cvLine( img, prev_pt, pt, cvScalarAll(255), 5, 8, 0 );
prev_pt = pt;
cvShowImage( "image", img );
}
}

int main( int argc, char** argv )
{
char* filename = argc >= 2 ? argv[1] : (char*)"fruits.jpg";
if( (img0 = cvLoadImage(filename,-1)) == 0 )
return 0;
printf( "Hot keys: \n"
cvNamedWindow( "image", 1 );
img = cvCloneImage( img0 );
inpainted = cvCloneImage( img0 );
inpaint_mask = cvCreateImage( cvGetSize(img), 8, 1 );
cvZero( inpaint_mask );
cvZero( inpainted );
cvShowImage( "image", img );
cvShowImage( "watershed transform", inpainted );
cvSetMouseCallback( "image", on_mouse, 0 );
}

第二步、将选择的区域提取出来

if(event == CV_EVENT_RBUTTONUP)
{
cvFloodFill(maskImg,cvPoint(x,y),cvScalarAll(255));
cvSaveImage("maskImg.bmp",maskImg);
IplImage *segImage=cvCreateImage(cvGetSize(img),8,3);;
cvCopy(img,segImage,maskImg);
cvSaveImage("segImage.bmp",segImage);
cvCopy(segImage,proc->img);
cvReleaseImage(&segImage);
cvDestroyWindow("Key Image");
}

听说上面代码有点问题，评轮如下：
我觉得大神可能只是给了方法，最后的再进行显示和保存的时候，这部分代码以应该修改一下：
if(event == CV_EVENT_RBUTTONUP) ，如果直接把这个语句加上去，是无法被执行的，因为右键的相应被前面的判断
if( event == CV_EVENT_LBUTTONUP || !(flags & CV_EVENT_FLAG_LBUTTON) ) 都终止了，所以要执行第二部分，最简单的是把if(event == CV_EVENT_RBUTTONUP)改成if(event == CV_EVENT_LBUTTONDBLCLK)，不然第一部分的判断应该修改下，第二部分的maskImg应该换成定义的前面定义的某个mask，这样就可以执行了