wglDescribeLayerPlane
[New
- Windows 95, OEM Service Release 2]
The wglDescribeLayerPlane
function obtains information about the layer planes of a given pixel
format.
BOOL wglDescribeLayerPlane(
|
HDC hdc, |
// device
context whose layer planes are of interest |
|
int iPixelFormat, |
// pixel
format of the desired layer plane |
|
int iLayerPlane, |
//
specifies an overlay or underlay plane |
|
UINT nBytes, |
//
specifies the size, in bytes, of a LAYERPLANEDESCRIPTOR structure |
|
LPLAYERPLANEDESCRIPTOR plpd |
// points
to a LAYERPLANEDESCRIPTOR structure |
|
); |
|
Parameters
hdc
Specifies the
device context of a window whose layer planes are to be described.
iPixelFormat
Specifies
which layer planes of a pixel format are being described.
iLayerPlane
Specifies the
overlay or underlay plane. Positive values of iLayerPlane identify
overlay planes, where 1 is the first overlay plane over the main plane, 2 is
the second overlay plane over the first overlay plane, and so on. Negative
values identify underlay planes, where -1 is the first underlay plane under the main plane, -2 is the second underlay plane under the first underlay
plane, and so on. The number of overlay and underlay planes is given in the bReserved
member of the PIXELFORMATDESCRIPTOR structure.
nBytes
Specifies the
size, in bytes, of the structure pointed to by plpd. The wglDescribeLayerPlane
function stores layer plane data in a LAYERPLANEDESCRIPTOR structure, and stores no
more than nBytes of data. Set the value of nBytes to the size of LAYERPLANEDESCRIPTOR.
plpd
Points to a LAYERPLANEDESCRIPTOR
structure. The wglDescribeLayerPlane function sets the value
of the structure s data members. The function stores the number of bytes of
data copied to the structure in the nSize member.
Return Values
If the
function succeeds, the return value is TRUE. In addition, the wglDescribeLayerPlane
function sets the members of the LAYERPLANEDESCRIPTOR structure pointed
to by plpd according to the specified layer plane (iLayerPlane)
of the specified pixel format (iPixelFormat).
If the
function fails, the return value is FALSE.
Remarks
The numbering
of planes (iLayerPlane) determines their order. Higher-numbered planes
overlay lower-numbered planes.
See Also