Updates the position, size, shape, content, and translucency of a layered window.
BOOL UpdateLayeredWindow(
   CDC* pDCDst,
   POINT *pptDst,
   SIZE *psize,
   CDC *pDCSrc,
   POINT *pptSrc,
   COLORREF crKey,
   BLENDFUNCTION *pblend,
   DWORD dwFlags
);
Parameters
- pDCDst 
 A pointer to a device context for the screen. It is used for palette color matching when the window contents are updated. If pDCDst is NULL, the default palette will be used.- If pDCSrc is NULL, pDCDst must be NULL. 
- pptDst 
 A pointer to a POINT structure specifying the new screen position of the layered window. If the current position is not changing, pptDst can be NULL.
- psize 
 Pointer to a SIZE structure that specifies the new size of the layered window. If the size of the window is not changing, psize can be NULL.- If pDCSrc is NULL, psize must be NULL. 
- pDCSrc 
 A pointer to a DC for the surface that defines the layered window. If the shape and visual context of the window are not changing, pDCSrc can be NULL.
- pptSrc 
 Pointer to a POINT structure that specifies the location of the layer in the device context.- If pDCSrc is NULL, pptSrc should be NULL. 
- crKey 
 Pointer to a COLORREF value that specifies the transparency color key to be used when composing the layered window. All pixels painted by the window in this color will be transparent. To generate a COLORREF, use the RGB macro.
- pblend 
 Pointer to a BLENDFUNCTION structure that specifies the transparency value to be used when composing the layered window.
- dwFlags 
 Specifies an action to take. This parameter can be one or more of the following values. For a list of possible values, seeUpdateLayeredWindow.
Return Value
Nonzero if the function succeeds; otherwise 0.
Remarks
This member function emulates the functionality of the function UpdateLayeredWindow, as described in the Windows SDK.
Requirements
Header: afxwin.h