MFC下的OpenCV截图与API函数截图

来源：互联网发布：帝国坟场知乎编辑：程序博客网时间：2024/05/13 14:00

1、使用OpenCV的函数截图，以下是一位网友写的http://blog.csdn.net/chenli2010/article/details/7899773

源代码如下：

#include<opencv/cv.h>
#include<opencv/highgui.h>
#include<iostream>

CvPoint pt1 = cvPoint(0,0);
CvPoint pt2 = cvPoint(0,0);
bool is_selecting = false;

// callback function
void cvMouseCallback(int mouseEvent,int x,int y,int flags,void* param)
{
switch(mouseEvent)
{
case CV_EVENT_LBUTTONDOWN:
  pt1 = cvPoint(x,y);
  pt2 = cvPoint(x,y);
  is_selecting = true;
  break;
case CV_EVENT_MOUSEMOVE:
  if(is_selecting)
   pt2 = cvPoint(x,y);
  break;
case CV_EVENT_LBUTTONUP:
  pt2 = cvPoint(x,y);
  is_selecting = false;
  break;
}
return;
}

int main(int argc,char* argv[])
{
char img_path[80] = "0.jpg";
char save_path[80] = "save.jpg";
char* window = "img";

IplImage* img = cvLoadImage(img_path);
IplImage* img_show = cvCloneImage(img);

cvNamedWindow(window,CV_WINDOW_AUTOSIZE);
cvSetMouseCallback(window,cvMouseCallback);

bool shift_on = false;

char text[80];
CvFont font;
cvInitFont(&font,CV_FONT_HERSHEY_PLAIN,1.0,1.0);
while(true)
{
  cvCopy(img,img_show);
  cvRectangle(img_show,pt1,pt2,cvScalar(255,255,255));
  sprintf(text,"roi = cvRect(%d,%d,%d,%d)",pt1.x,pt1.y,std::abs(pt2.x-pt1.x),std::abs(pt2.y-pt1.y));
  cvPutText(img_show,text,cvPoint(10,20),&font,cvScalar(0,0,255));

  cvShowImage(window,img_show);
  char key = cvWaitKey(10);
  switch(key)
  {
  case '\t':
   shift_on = !shift_on; break;

  case 'a':
   pt1.x--; pt2.x--; break;
  case 's':
   pt1.y++; pt2.y++; break;
  case 'd':
   pt1.x++; pt2.x++; break;
  case 'w':
   pt1.y--; pt2.y--; break;

  case '1':
   if(shift_on) pt1.x--;
   else pt2.x--;
   break;
  case '2':
   if(shift_on) pt2.y++;
   else pt1.y++;
   break;
  case '3':
   if(shift_on) pt2.x++;
   else pt1.x++;
   break;
  case '5':
   if(shift_on) pt1.y--;
   else pt2.y--;
   break;

  case '\r':
   cvSetImageROI(img,cvRect(pt1.x,pt1.y,std::abs(pt2.x-pt1.x),std::abs(pt2.y-pt1.y)));
   cvSaveImage(save_path,img);
   cvResetImageROI(img);
   break;
  };

if(key==27) break;
}

cvReleaseImage(&img);
cvReleaseImage(&img_show);
return 0;
}

2、使用系统的API函数

以下摘自http://hi.baidu.com/winkyao/blog/item/db7e3fd07540023e06088b29.html

先在CCupWindowDlg的头文件中定义一个私有变量CDC CompatibleDC；

void CCupWindowDlg::OnButton1()
{
// TODO: Add your control notification handler code here
bCapture=TRUE;

int cx=GetSystemMetrics(SM_CXSCREEN);                   //这里重新设置了对话框的大小，置顶对话框，而且去除了VC的边框
int cy=GetSystemMetrics(SM_CYSCREEN);
    //保存原来窗口的大小，以便恢复
GetClientRect(&rectOld);
CDC   dc;
    dc.CreateDC("DISPLAY",NULL,NULL,NULL);
CBitmap   bitmap;                 //创建一个位图，得到了这个位图句柄，也就是API当中的HBITMAP，一切就好办了
bitmap.CreateCompatibleBitmap(&dc,cx,cy);    //为其创建一个兼容的位图
    if(!CompatibleDC.m_hDC )
{
  CompatibleDC.CreateCompatibleDC(&dc);
}
    CBitmap *pOld=CompatibleDC.SelectObject(&bitmap);   //兼容DC在初始化时是以单色位图初始化的，把位图句柄选进兼容DC,扩展其显示面大小。
CompatibleDC.StretchBlt(0,0,cx,cy,&dc,0,0,cx,cy,SRCCOPY);
     //这里，把整个屏幕的图，贴到了内存设备描述表

ModifyStyle(WS_BORDER,0,0); //要在获取到了屏幕位图之后，再置顶窗口，不然会截取失败
this->SetWindowPos(&wndTopMost,0,0,cx,cy,SWP_SHOWWINDOW);

CompatibleDC.SelectObject(pOld);
//接下来当然是改变对话框的设备描述表了。响应WM_ERASEBKGND消息

}

BOOL CCupWindowDlg::OnEraseBkgnd(CDC* pDC)
{
// TODO: Add your message handler code here and/or call default
    if(bCapture)
{
  CBitmap bitmap;
  CRect rect;
  GetClientRect(&rect);
  pDC->BitBlt(0,0,rect.Width(),rect.Height(),&CompatibleDC,0,0,SRCCOPY);
  return TRUE;
}
else
  return CDialog::OnEraseBkgnd(pDC);
}

void CCupWindowDlg::OnLButtonDown(UINT nFlags, CPoint point)
{
// TODO: Add your message handler code here and/or call default
if(!bClicking&& bCapture)           //已经按了截图键
{
  bClicking=TRUE;
        ptBeg=point;
  ptEnd=ptBeg;
}

CDialog::OnLButtonDown(nFlags, point);
}

void CCupWindowDlg::OnMouseMove(UINT nFlags, CPoint point)
{
// TODO: Add your message handler code here and/or call default
if(bClicking && bCapture)
{
  HDC hdc;
  hdc=::GetDC(m_hWnd);
        DrawBlock(hdc,ptBeg,ptEnd);
  ptEnd=point;
  DrawBlock(hdc,ptBeg,ptEnd);
  ::ReleaseDC(m_hWnd,hdc);
}

CDialog::OnMouseMove(nFlags, point);
}

//按下右键，可以撤销

void CCupWindowDlg::OnRButtonDown(UINT nFlags, CPoint point)
{
// TODO: Add your message handler code here and/or call default
if(bCapture)
{
bCapture=FALSE;
::SetWindowPos(m_hWnd,HWND_NOTOPMOST,0,0,rectOld.right-rectOld.left,rectOld.bottom-rectOld.top,SWP_SHOWWINDOW);
}
CDialog::OnRButtonDown(nFlags, point);
}

void CCupWindowDlg::DrawBlock(HDC hdc,POINT ptBeg,POINT ptEnd)
{
SetROP2(hdc,R2_NOT); //如果已经画了，那么就擦除
SelectObject(hdc,GetStockObject(NULL_BRUSH));
Rectangle(hdc,ptBeg.x,ptBeg.y,ptEnd.x,ptEnd.y);
}