Platform SDK: DirectX

IDirectDraw7::GetScanLine

The IDirectDraw7::GetScanLine method retrieves the scan line that is currently being drawn on the monitor.

HRESULT GetScanLine(
  LPDWORD lpdwScanLine  
);

Parameters

lpdwScanLine
Address of a variable to contain the scan line that the display is currently drawing.

Return Values

If the method succeeds, the return value is DD_OK.

If it fails, the method can return one of the following error values:

DDERR_INVALIDOBJECT
DDERR_INVALIDPARAMS
DDERR_UNSUPPORTED
DDERR_VERTICALBLANKINPROGRESS

Remarks

Scan lines are reported as zero-based integers. The returned scan line value is in the range from 0 through n, where 0 is the first visible scan line on the screen and n is the last visible scan line, plus any scan lines that occur during the vertical blank period. So, in a case where an application is running at a resolution of 640×480 and there are 12 scan lines during vblank, the values returned by this method range from 0 through 491.

Requirements

  Windows NT/2000: Requires Windows 2000.
  Windows 95/98: Requires Windows 98.
  Header: Declared in ddraw.h.

See Also

IDirectDraw7::GetVerticalBlankStatus, IDirectDraw7::WaitForVerticalBlank