屏幕及窗口拷贝

以下来自于：http://www.codeguru.com/forum/showthread.php?t=244907

#define PW_WINDOW 9001
#define PW_CLIENT 9002

HBITMAP CMyProgramDlg::CopyScreenToBitmap(LPRECT lpRect)
{
HDC hScrDC, hMemDC; // screen DC and memory DC
int nX, nY, nX2, nY2; // coordinates of rectangle to grab
int nWidth, nHeight; // DIB width and height
int xScrn, yScrn; // screen resolution

HGDIOBJ hOldBitmap , hBitmap;

// check for an empty rectangle
if (IsRectEmpty(lpRect))
return NULL;
// create a DC for the screen and create
// a memory DC compatible to screen DC

hScrDC = CreateDC("DISPLAY", NULL, NULL, NULL);
hMemDC = CreateCompatibleDC(hScrDC); // get points of rectangle to grab

nX = lpRect->left;
nY = lpRect->top;
nX2 = lpRect->right;
nY2 = lpRect->bottom; // get screen resolution

xScrn = GetDeviceCaps(hScrDC, HORZRES);
yScrn = GetDeviceCaps(hScrDC, VERTRES);

//make sure bitmap rectangle is visible

if (nX < 0)
nX = 0;

if (nY < 0)
nY = 0;

if (nX2 > xScrn)
nX2 = xScrn;

if (nY2 > yScrn)
nY2 = yScrn;

nWidth = nX2 - nX;
nHeight = nY2 - nY;

// create a bitmap compatible with the screen DC

hBitmap = CreateCompatibleBitmap(hScrDC, nWidth, nHeight);

// select new bitmap into memory DC

hOldBitmap = SelectObject (hMemDC, hBitmap);

// bitblt screen DC to memory DC

BitBlt(hMemDC, 0, 0, nWidth, nHeight, hScrDC, nX, nY, SRCCOPY);

// select old bitmap back into memory DC and get handle to
// bitmap of the screen

hBitmap = SelectObject(hMemDC, hOldBitmap);

// clean up

DeleteDC(hScrDC);
DeleteDC(hMemDC);

// return handle to the bitmap

return (HBITMAP)hBitmap;
}

HBITMAP CYourProgramDlg::CopyWindowToBitmap(CWnd* wnd , HWND hWnd, WORD fPrintArea)
{
HBITMAP hBitmap = NULL; // handle to device-dependent bitmap
// check for a valid window handle
if (!hWnd)
return NULL;

RECT rectWnd;
::GetWindowRect(hWnd, &rectWnd);

switch (fPrintArea)
{
case PW_WINDOW: // copy entire window
{
// get the window rectangle
// get the bitmap of that window by calling
// CopyScreenToBitmap and passing it the window rect
// GetWindowRect(&rectWnd);
hBitmap = CopyScreenToBitmap(&rectWnd);
break;
}
case PW_CLIENT: // copy client area
{
RECT rectClient;
POINT pt1, pt2; // get client dimensions
wnd->GetClientRect(&rectClient); // convert client coords to screen coords
pt1.x = rectClient.left;
pt1.y = rectClient.top;
pt2.x = rectClient.right;
pt2.y = rectClient.bottom;
wnd->ClientToScreen(&pt1);
wnd->ClientToScreen(&pt2);
rectClient.left = pt1.x;
rectClient.top = pt1.y;
rectClient.right = pt2.x;
rectClient.bottom = pt2.y;

// get the bitmap of the client area by calling
// CopyScreenToBitmap and passing it the client rect
hBitmap = CopyScreenToBitmap(&rectClient);
break;
}
default: // invalid print area
return NULL;
} // return handle to the bitmap

return hBitmap;
}A good usage is :

Code:
HBITMAP hBitmap = CopyWindowToBitmap(this,GetDesktopWindow()->m_hWnd,PW_