LOGCOLORSPACEA structure (wingdi.h)

The LOGCOLORSPACE structure contains information that defines a logical color space.


typedef struct tagLOGCOLORSPACEA {
  DWORD         lcsSignature;
  DWORD         lcsVersion;
  DWORD         lcsSize;
  LCSCSTYPE     lcsCSType;
  CIEXYZTRIPLE  lcsEndpoints;
  DWORD         lcsGammaRed;
  DWORD         lcsGammaGreen;
  DWORD         lcsGammaBlue;
  CHAR          lcsFilename[MAX_PATH];



Color space signature. At present, this member should always be set to LCS_SIGNATURE.


Version number; must be 0x400.


Size of this structure, in bytes.


Color space type. The member can be one of the following values.

Value Meaning
LCS_CALIBRATED_RGB Color values are calibrated RGB values. The values are translated using the endpoints specified by the lcsEndpoints member before being passed to the device.
LCS_sRGB Color values are values are sRGB values.
LCS_WINDOWS_COLOR_SPACE Color values are Windows default color space color values.

If LCS_CALIBRATED_RGB is not specified, the lcsEndpoints member is ignored.


The gamut mapping method. This member can be one of the following values.

Value Intent ICC Name Meaning
Match Absolute Colorimetric Maintain the white point. Match the colors to their nearest color in the destination gamut.
Graphic Saturation Maintain saturation. Used for business charts and other situations in which undithered colors are required.
Proof Relative Colorimetric Maintain colorimetric match. Used for graphic designs and named colors.
Picture Perceptual Maintain contrast. Used for photographs and natural images.


Red, green, blue endpoints.


Scale of the red coordinate.


Scale of the green coordinate.


Scale of the blue coordinate.


A null-terminated string that names a color profile file. This member is typically set to zero, but may be used to set the color space to be exactly as specified by the color profile. This is useful for devices that input color values for a specific printer, or when using an installable image color matcher. If a color profile is specified, all other members of this structure should be set to reasonable values, even if the values are not completely accurate.


Like palettes, but unlike pens and brushes, a pointer must be passed when creating a LogColorSpace.

If the lcsCSType member is set to LCS_sRGB or LCS_WINDOWS_COLOR_SPACE, the other members of this structure are ignored, and WCS uses the sRGB color space. The lcsEndpoints,lcsGammaRed, lcsGammaGreen, and lcsGammaBlue members are used to describe the logical color space. The lcsEndpoints member is a CIEXYZTRIPLE that contains the x, y, and z values of the color space's RGB endpoint.

The required DWORD bit format for the lcsGammaRed, lcsGammaGreen, and lcsGammaBlue is an 8.8 fixed point integer left-shifted by 8 bits. This means 8 integer bits are followed by 8 fraction bits. Taking the bit shift into account, the required format of the 32-bit DWORD is:


Whenever the lcsFilename member contains a file name and the lcsCSType member is set to LCS_CALIBRATED_RGB, WCS ignores the other members of this structure. It uses the color space in the file as the color space to which this LOGCOLORSPACE structure refers.

The relation between tri-stimulus values X,Y,Z and chromaticity values x,y,z is as follows:

x = X/(X+Y+Z)

y = Y/(X+Y+Z)

z = Z/(X+Y+Z)

If the lcsCSType member is set to LCS_sRGB or LCS_WINDOWS_COLOR_SPACE, the other members of this structure are ignored, and ICM uses the sRGB color space. Applications should still initialize the rest of the structure since CreateProfileFromLogColorSpace ignores lcsCSType member and uses lcsEndpoints, lcsGammaRed, lcsGammaGreen, lcsGammaBlue members to create a profile, which may not be initialized in case of LCS_sRGB or LCS_WINDOWS_COLOR_SPACE color spaces.


The wingdi.h header defines LOGCOLORSPACE as an alias which automatically selects the ANSI or Unicode version of this function based on the definition of the UNICODE preprocessor constant. Mixing usage of the encoding-neutral alias with code that not encoding-neutral can lead to mismatches that result in compilation or runtime errors. For more information, see Conventions for Function Prototypes.


Requirement Value
Minimum supported client Windows 2000 Professional [desktop apps only]
Minimum supported server Windows 2000 Server [desktop apps only]
Header wingdi.h

See also