LAB_PARAMS

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typedef struct
{
    L_UINT uStructSize;
    L_INT nMask;
    L_INT L_offset;
    L_INT L_range;
    L_INT a_offset;
    L_INT a_range;
    L_INT b_offset;
    L_INT b_range;
} LAB_PARAMS, *LPLAB_PARAMS;

The LAB_PARAMS structure provides information about CIELab conversion properties.

Parameter	Description
uStructSize	Size of this structure.
nMask	Masking value:
	Value	Meaning
	LAB_L_OFFSET	Change L_offset value
	LAB_L_RANGE	Change L_range value
	LAB_a_OFFSET	Change a_offset value
	LAB_a_RANGE	Change a_range value
	LAB_b_OFFSET	Change b_offset value
	LAB_b_RANGE	Change b_range value
L_offset	L component offset
L_range	L componnt range
a_offset	a component offset
a_range	a Component range
b_offset	b Component offset
b_range	b Component range

Comments

The gamut capacity is expressed as an offset and range, with the exception of the minimum and maximum values. For example, in the T.42 CIELab, the communication conversion can be expressed as:

L_offset = 0;
L_range = 100
a_offset = 128
a_range = 170
b_offset = 96
b_range = 200

For more information on the CIELab color conversion, refer to www.itu.int.

LAB_PARAMS is used with the CONVERSION_PARAM structure.

The mask value will be used only when updating the CMYK conversion using LColor::SetConversionParams function.