关于截屏软件的做法

Question

大虾们:好!我最近想做一个截屏的软件,但因我是个新手,不知从何入手,现非常的
烦恼.请大家们帮忙了!

Answer 1

1)获取屏幕DC得到屏幕DC，多种方法:
CDC *pDC = GetDC(NULL);
CDC *pDC = CDC::FromHandle(::GetDC(::GetDesktopWindow()));
CClientDC dc(NULL);2)画图
有了屏幕DC之后，就可以画出来了.有关代码可参考
http://expert.csdn.net/Expert/topic/649/649984.xml?temp=.5050318

Answer 2

但是图象如果要在网上传输的话太大了
用MPEG1压缩的话  具体的算法是如何实现的呢

Answer 3

http://www.csdn.net/Dev/Format/应该可以找到你想要的东西

Answer 4

void CCaptureView::OnCaptureScreen() 
{
// TODO: Add your command handler code here
CDC dc;
dc.CreateDC("DISPLAY",NULL,NULL,NULL);
int SrcWidth=GetSystemMetrics(SM_CXSCREEN);
int SrcHeight=GetSystemMetrics(SM_CYSCREEN);
// int Width=384,Height=288;
int Width=SrcWidth,Height=SrcHeight;
/* CDC memdc;
memdc.CreateCompatibleDC(&dc);
memdc.StretchBlt(0,0,Width,Height,&dc,0,0,SrcWidth,SrcHeight,SRCCOPY);
*/
CBitmap bm;
bm.CreateCompatibleBitmap(&dc,Width,Height);
CDC tdc;
tdc.CreateCompatibleDC(&dc);
CBitmap*pOld=tdc.SelectObject(&bm);
tdc.SetStretchBltMode(STRETCH_HALFTONE);
tdc.StretchBlt(0,0,Width,Height,&dc,0,0,SrcWidth,SrcHeight,SRCCOPY);
// tdc.BitBlt(0,0,Width,Height,&dc,0,0,SRCCOPY);
tdc.SelectObject(pOld);
BITMAP btm;
bm.GetBitmap(&btm);
DWORD size=btm.bmWidthBytes*btm.bmHeight;
LPSTR lpData=(LPSTR)GlobalAllocPtr(GPTR,size);
/////////////////////////////////////////////
BITMAPINFOHEADER bih;
bih.biBitCount=btm.bmBitsPixel;
bih.biClrImportant=0;
bih.biClrUsed=0;
bih.biCompression=0;
bih.biHeight=btm.bmHeight;
bih.biWidth=btm.bmWidth;
bih.biPlanes=1;
bih.biSize=sizeof(BITMAPINFOHEADER);
bih.biSizeImage=size;
bih.biXPelsPerMeter=0;
bih.biYPelsPerMeter=0;
///////////////////////////////////
GetDIBits(dc,bm,0,bih.biHeight,lpData,(BITMAPINFO*)&bih,DIB_RGB_COLORS);
// bm.GetBitmapBits(size,lpData); //此函数在处理5-5-5模式的16位色下会出现颜色混乱
//////////////////////////////
static int filecount=0;
BITMAPFILEHEADER bfh;
bfh.bfReserved1=bfh.bfReserved2=0;
bfh.bfType=((WORD)('M'<< 8)|'B');
bfh.bfSize=54+size;
bfh.bfOffBits=54;
CFile bf;
if(bf.Open("capture.bmp",CFile::modeCreate|CFile::modeWrite)){
bf.WriteHuge(&bfh,sizeof(BITMAPFILEHEADER));
bf.WriteHuge(&bih,sizeof(BITMAPINFOHEADER));
bf.WriteHuge(lpData,size);
bf.Close();
// nCount++;
}
GlobalFreePtr(lpData);
UpdateData(FALSE);
}void CCaptureView::OnCaptureScreen1() 
{
// TODO: Add your command handler code here
char filename[30]="capture1.bmp";
HDC hdc;
HDC hdc2;
DWORD dwWidth, dwHeight, dwBPP, dwNumColors;
HBITMAP bitmap;
HGDIOBJ gdiobj;
LPVOID pBits;
BITMAPFILEHEADER bitmapfileheader;
BITMAPINFOHEADER bitmapinfoheader; hdc=CreateDC("DISPLAY", NULL, NULL, NULL);
if(hdc==NULL) {
AfxMessageBox("Couldn't create device context.\n");
return ;
}

dwWidth = GetDeviceCaps(hdc, HORZRES);
dwHeight = GetDeviceCaps(hdc, VERTRES);
dwBPP = GetDeviceCaps(hdc, BITSPIXEL); if(dwBPP<=8) {
dwNumColors = GetDeviceCaps(hdc, NUMCOLORS);
// dwNumColors = 256;
} else {
dwNumColors = 0;
}
CString temp;
temp.Format("%d",dwNumColors);
AfxMessageBox(temp); hdc2=CreateCompatibleDC(hdc);
if(hdc2==NULL) {
DeleteDC(hdc);
AfxMessageBox("Couldn't create compatible device context.\n");
return ;
}
bitmapfileheader.bfType = 0x4D42;
bitmapfileheader.bfSize = ((dwWidth * dwHeight * dwBPP)/8) + sizeof(BITMAPFILEHEADER) + sizeof(BITMAPINFOHEADER) + (dwNumColors * sizeof(RGBQUAD));
bitmapfileheader.bfReserved1 = 0;
bitmapfileheader.bfReserved2 = 0;
bitmapfileheader.bfOffBits = sizeof(BITMAPFILEHEADER) + sizeof(BITMAPINFOHEADER) + (dwNumColors * sizeof(RGBQUAD));  

bitmapinfoheader.biSize = sizeof(BITMAPINFOHEADER);
bitmapinfoheader.biWidth = dwWidth;
bitmapinfoheader.biHeight = dwHeight;
bitmapinfoheader.biPlanes = 1;
bitmapinfoheader.biBitCount = (WORD)dwBPP;
bitmapinfoheader.biCompression = BI_RGB;
bitmapinfoheader.biSizeImage = 0;
bitmapinfoheader.biXPelsPerMeter = 0;
bitmapinfoheader.biYPelsPerMeter = 0;
bitmapinfoheader.biClrUsed = dwNumColors;
bitmapinfoheader.biClrImportant = 0; bitmap = CreateDIBSection(hdc, (BITMAPINFO *)&bitmapinfoheader, DIB_PAL_COLORS, &pBits, NULL, 0);
if(bitmap==NULL) {
DeleteDC(hdc);
DeleteDC(hdc2);
AfxMessageBox("Couldn't create compatible bitmap.\n");
return ;
}
gdiobj = SelectObject(hdc2, (HGDIOBJ)bitmap);
if((gdiobj==NULL) || (gdiobj==(void *)GDI_ERROR)) {
DeleteDC(hdc);
DeleteDC(hdc2);
AfxMessageBox("Couldn't select bitmap.\n");
return ;
}
if (!BitBlt(hdc2, 0,0, dwWidth, dwHeight, hdc, 0,0, SRCCOPY)) {
DeleteDC(hdc);
DeleteDC(hdc2);
AfxMessageBox("Couldn't copy bitmap.\n");
return ;
}

RGBQUAD colors[256];
if(dwNumColors!=0) {
dwNumColors = GetDIBColorTable(hdc2, 0, dwNumColors, colors);
}

HANDLE hfile;
DWORD dwBytes;

hfile=CreateFile(filename,GENERIC_WRITE,0,NULL,CREATE_ALWAYS,FILE_ATTRIBUTE_NORMAL,NULL);
if(hfile==INVALID_HANDLE_VALUE) {
DeleteObject(bitmap);
DeleteDC(hdc2);
DeleteDC(hdc);
AfxMessageBox("Couldn't write file to disk.\n");
return ;
}
WriteFile(hfile,&bitmapfileheader,sizeof(BITMAPFILEHEADER), &dwBytes, NULL);
WriteFile(hfile,&bitmapinfoheader,sizeof(BITMAPINFOHEADER), &dwBytes, NULL);
if(dwNumColors!=0)
WriteFile(hfile,colors,sizeof(RGBQUAD)*dwNumColors,&dwBytes,NULL);
WriteFile(hfile,pBits,(dwWidth*dwHeight*dwBPP)/8,&dwBytes,NULL);
CloseHandle(hfile);


DeleteObject(bitmap);
DeleteDC(hdc2);
DeleteDC(hdc);

return ;
}