PDD_SURFCB_UPDATEOVERLAY callback function (ddrawint.h)

The DdUpdateOverlay callback function repositions or modifies the visual attributes of an overlay surface.

Syntax

PDD_SURFCB_UPDATEOVERLAY PddSurfcbUpdateoverlay;

DWORD PddSurfcbUpdateoverlay(
  PDD_UPDATEOVERLAYDATA unnamedParam1
)
{...}

Parameters

unnamedParam1

Points to a DD_UPDATEOVERLAYDATA structure that contains the information required to update the overlay.

Return value

DdUpdateOverlay returns one of the following callback codes:

Remarks

DdUpdateOverlay shows, hides, or repositions an overlay surface on the screen. It also sets attributes of the overlay surface, such as the stretch factor or type of color key to be used.

The driver should determine whether it has the bandwidth to support the overlay update request. The driver should use the dwFlags member of the DD_UPDATEOVERLAYDATA structure at lpUpdateOverlay to determine the type of request and how to process it.

The driver/hardware must stretch or shrink the overlay accordingly when the rectangles specified by the rDest and rSrc members of DD_UPDATEOVERLAYDATA are different sizes.

Note that DdFlip is used for flipping between overlay surfaces, so performance for DdUpdateOverlay is not critical.

Requirements

See also

DD_UPDATEOVERLAYDATA

DdFlip

DdSetColorKey

DdSetOverlayPosition