DrvSetPointerShape function

The DrvSetPointerShape function is used to request the driver to take the pointer off the display, if the driver has drawn it there; to attempt to set a new pointer shape; and to put the new pointer on the display at a specified position.

Syntax

ULONG DrvSetPointerShape(
  SURFOBJ  *pso,
  SURFOBJ  *psoMask,
  SURFOBJ  *psoColor,
  XLATEOBJ *pxlo,
  LONG     xHot,
  LONG     yHot,
  LONG     x,
  LONG     y,
  RECTL    *prcl,
  FLONG    fl
);

Parameters

pso

Pointer to a SURFOBJ structure that describes the surface on which to draw.

psoMask

Pointer to the SURFOBJ structure that defines the AND-XOR mask. (The AND-XOR mask is described in Drawing Monochrome Pointers.) The dimensions of this bitmap determine the size of the pointer. There are no implicit constraints on pointer sizes, but optimal pointer sizes are 32 x 32, 48 x 48, and 64 x 64 pixels. If this parameter is NULL, the pointer is transparent.

psoColor

Pointer to the SURFOBJ structure that defines the colors for a color pointer. If this parameter is NULL, the pointer is monochrome. The pointer bitmap has the same width as psoMask and half the height.

pxlo

Pointer to a XLATEOBJ structure that defines the colors in psoColor.

xHot

Specify the x position of the pointer's hot spot relative to its upper-left pixel. The pixel indicated by the hot spot should be positioned at the new pointer position.

yHot

Specify the y position of the pointer's hot spot relative to its upper-left pixel. The pixel indicated by the hot spot should be positioned at the new pointer position.

x

Specify the x-coordinate of the new pointer position.

y

Specify the y-coordinate of the new pointer position.

prcl

Specifies the RECTL structure that indicates the location in which the driver should write a rectangle that specifies a tight bound for the visible portion of the pointer.

fl

Specifies an extensible set of flags. The driver should decline the call if any flags are set that it does not understand. This parameter can be one or more of the following predefined values, and one or more driver-defined values:

Flag Meaning
SPS_ALPHA The pointer has per-pixel alpha values.
SPS_ANIMATESTART The driver should be prepared to receive a series of similarly-sized pointer shapes that will comprise an animated pointer effect.
SPS_ANIMATEUPDATE The driver should draw the next pointer shape in the animated series.
SPS_ASYNCCHANGE This flag is obsolete. For legacy drivers, the driver should accept the change only if it is capable of changing the pointer shape in the hardware while other drawing is underway on the device. GDI uses this option only if the now obsolete GCAPS_ASYNCCHANGE flag is set in the flGraphicsCaps member of the DEVINFO structure.
SPS_CHANGE The driver is requested to change the pointer shape.
SPS_FREQMASK The driver is requested to render a mouse trail, updating the image as many times per millisecond as indicated in the expression fl & SPS_FREQMASK. A driver that is capable of rendering mouse trails must have the GCAPS2_MOUSETRAILS flag set in the flGraphicsCaps2 member of its DEVINFO structure.
SPS_LENGTHMASK The driver is requested to render a mouse trail of length indicated by the expression fl & SPS_LENGTHMASK. (A mouse trail of length N is made up of N + 1 cursor images.) A driver that is capable of rendering mouse trails must have the GCAPS2_MOUSETRAILS flag set in the flGraphicsCaps2 member of its DEVINFO structure.

Return Value

The return value can be one of the following values:

Return code Description
SPS_ACCEPT_EXCLUDE
Is obsolete. GDI will disable the driver's pointer and revert to software simulation if the driver returns this value.
SPS_ACCEPT_NOEXCLUDE
The driver accepts the shape. The shape is supported in hardware and GDI is not concerned about other drawings overwriting the pointer.
SPS_DECLINE
The driver does not support the shape, so GDI must simulate it.
SPS_ERROR
The driver normally supports this shape, but failed for unusual reasons.

Remarks

DrvSetPointerShape is optional for display drivers. If this function is implemented, however, DrvMovePointer must also be implemented.

The iUniq members of the SURFOBJ structures to which psoMask and psoColor point are unique for unique pointers. The driver can use this information in conjunction with these structures' unique dhsurf handles as cache keys for cursor caching.

When SPS_ALPHA is set in the fl parameter, psoMask is NULL and psoColor points to a 32bpp BGRA surface. The per-pixel alpha value indicates the opacity of the corresponding pointer pixel with the desktop pixel underneath. The source alpha format is premultiplied; that is, each of the color channels of the source surface has already been premultiplied with the corresponding alpha value, thus eliminating a multiply operation at the time of the blend.

Default alpha cursors are largely black and white with a large range of alpha values; however, there is no color restriction since applications can specify arbitrary cursors themselves. Typical alpha pointer sizes are approximately 8 pixels larger in dimension than typical pointers without alpha. This accommodates the shadow effect, which is accomplished by a blurring filter that expands the resulting pointer bitmap shape. The vast majority of pointers will be 64x64 pixel bitmaps or smaller.

The driver indicates its ability to handle pointers with per-pixel alpha values by setting the GCAPS2_ALPHACURSOR flag in the flGraphicsCaps2 member of the DEVINFO structure returned by DrvEnablePDEV.

Requirements

   
Target Platform Desktop
Header winddi.h (include Winddi.h)

See Also

DrvEnablePDEV

DrvMovePointer

SURFOBJ

XLATEOBJ