EngQueryPalette function (winddi.h)

Article
10/05/2021

The EngQueryPalette function queries the specified palette for its attributes.

Syntax

ENGAPI ULONG EngQueryPalette(
  HPALETTE hpal,
  ULONG    *piMode,
  ULONG    cColors,
  ULONG    *pulColors
);

Parameters

hpal

Handle to the palette to be queried.

piMode

Pointer to a location that receives the palette mode, as originally specified in EngCreatePalette.

cColors

Specifies the number of entries in the buffer to which pulColors points. The return value depends on whether cColors is negative.

pulColors

Pointer to a buffer that receives the palette color information. If cColors is zero, pulColors can be NULL.

Return value

When cColors is zero, EngQueryPalette returns the number of palette entries required in the buffer to which pulColors points in order to return the palette color information. When cColors is nonzero and pulColors is not NULL, EngQueryPalette returns the number of entries written in the buffer to which pulColors points.

Remarks

If the palette mode is PAL_BITFIELDS, PAL_RGB, or PAL_BGR and the buffer that pulColors points to is large enough, pulColors points to three ULONG masks that represent the red, green, and blue color masks of the palette.

If the palette mode is PAL_INDEXED and the buffer that pulColors points to is large enough, pulColors contains all of the 24-bit RGB values that represent the palette colors.

A driver must test for the presence of the GCAPS_PALMANAGED flag to determine whether the colors represent a fixed or a changeable palette.

EngQueryPalette is intended for use by mirroring drivers that need to know the color format of the primary display. A mirroring driver typically calls this function in its DrvEnablePDEV routine.

Requirements

Requirement	Value
Minimum supported client	Available in Windows 2000 and later versions of the Windows operating systems.
Target Platform	Universal
Header	winddi.h (include Winddi.h)
Library	Win32k.lib
DLL	Win32k.sys