C / C++ / MFC

• Get the currently active window
  
• Make the target window the active window
  
• Capture its bitmap to the clipboard[^]
  
• Restore the state of the previously active window

<br />
int	Screenshot(HDC hdc, char *pszflname)<br />
{<br />
	HDC					memdc;<br />
	HANDLE				hfl;<br />
	DWORD				dwBytes, dwWidth, dwHeight, dwNumColors, dwBPP, ColorSize;<br />
	void				*pBits;<br />
	HBITMAP				hbmp;<br />
	BITMAPFILEHEADER	fileheader;<br />
	BITMAPINFOHEADER	infoheader;<br />
	RGBQUAD				colors[256];<br />
	BITMAPINFO			bmpinfo;<br />
	HGDIOBJ				hret;<br />
<br />
	dwWidth = GetDeviceCaps(hdc, HORZRES);<br />
	dwHeight = GetDeviceCaps(hdc, VERTRES);<br />
	dwBPP = GetDeviceCaps(hdc, BITSPIXEL);<br />
	if (dwBPP <= 8)<br />
		dwNumColors = 256;<br />
	else<br />
		dwNumColors = 0;<br />
	if (!(memdc = CreateCompatibleDC(hdc)))<br />
		return (0);<br />
	bmpinfo.bmiHeader.biSize = sizeof(BITMAPINFOHEADER);<br />
	bmpinfo.bmiHeader.biWidth = dwWidth;<br />
	bmpinfo.bmiHeader.biHeight = dwHeight;<br />
	bmpinfo.bmiHeader.biPlanes = 1;<br />
	bmpinfo.bmiHeader.biBitCount = (WORD)dwBPP;<br />
	bmpinfo.bmiHeader.biCompression = BI_RGB;<br />
	bmpinfo.bmiHeader.biSizeImage = 0;<br />
	bmpinfo.bmiHeader.biXPelsPerMeter = 0;<br />
	bmpinfo.bmiHeader.biYPelsPerMeter = 0;<br />
	bmpinfo.bmiHeader.biClrUsed = dwNumColors;<br />
	bmpinfo.bmiHeader.biClrImportant = dwNumColors;<br />
	hbmp = CreateDIBSection(hdc, &bmpinfo, DIB_PAL_COLORS, &pBits, NULL, 0);<br />
	if (!hbmp)<br />
	{<br />
		DeleteDC(memdc);<br />
		return (0);<br />
	}<br />
	hret = SelectObject(memdc, hbmp);<br />
	if (!hret || (hret == HGDI_ERROR))<br />
	{<br />
		DeleteDC(memdc);<br />
		return (0);<br />
	}<br />
	if (!BitBlt(memdc, 0, 0, dwWidth, dwHeight, hdc, 0, 0, SRCCOPY))<br />
	{<br />
		DeleteDC(memdc);<br />
		return (0);<br />
	}<br />
	if (dwNumColors)<br />
		dwNumColors = GetDIBColorTable(memdc, 0, dwNumColors, colors);<br />
	fileheader.bfType = 0x4D42;<br />
	ColorSize = dwNumColors * sizeof(RGBQUAD);<br />
	fileheader.bfSize = ((dwWidth*dwHeight*dwBPP) >> 3) + ColorSize + sizeof(BITMAPFILEHEADER) + sizeof(BITMAPINFOHEADER);<br />
	fileheader.bfReserved1 = fileheader.bfReserved2 = 0;<br />
	fileheader.bfOffBits = ColorSize + sizeof(BITMAPFILEHEADER) + sizeof(BITMAPINFOHEADER);<br />
	infoheader.biSize = sizeof(BITMAPINFOHEADER);<br />
	infoheader.biWidth = dwWidth;<br />
	infoheader.biHeight = dwHeight;<br />
	infoheader.biPlanes = 1;<br />
	infoheader.biBitCount = (WORD)dwBPP;<br />
	infoheader.biCompression = BI_RGB;<br />
	infoheader.biSizeImage = infoheader.biClrImportant = 0;<br />
	infoheader.biXPelsPerMeter = infoheader.biYPelsPerMeter = 0;<br />
	infoheader.biClrUsed = dwNumColors;<br />
	hfl = CreateFile(pszflname, GENERIC_WRITE, 0, 0, CREATE_ALWAYS, FILE_ATTRIBUTE_NORMAL, 0);<br />
	if (hfl == INVALID_HANDLE_VALUE)<br />
	{<br />
		DeleteObject(hbmp);<br />
		{<br />
			DeleteDC(memdc);<br />
			return (0);<br />
		}<br />
	}<br />
	WriteFile(hfl, &fileheader, sizeof(BITMAPFILEHEADER), &dwBytes, 0);<br />
	WriteFile(hfl, &infoheader, sizeof(BITMAPINFOHEADER), &dwBytes, 0);<br />
	if (!dwNumColors)<br />
		WriteFile(hfl, colors, ColorSize, &dwBytes, 0);<br />
	ColorSize = (dwWidth * dwHeight * dwBPP) >> 3;<br />
	WriteFile(hfl, pBits, ColorSize, &dwBytes, 0);<br />
	CloseHandle(hfl);<br />
	DeleteObject(hbmp);<br />
	DeleteDC(memdc);<br />
	return (1);<br />
}<br />

<br />
Screenshot(GetDC(GetDesktopWindow()), "myscreenshot.bmp");<br />