.TH LIBCOLOUR_YDBDR 7 libcolour
.SH NAME
LIBCOLOUR_YDBDR - YDbDr
.SH DESCRIPTION
YDbDr colours are presented with either of
.nf

	typedef struct libcolour_ydbdr_f libcolour_ydbdr_f_t;
	typedef struct libcolour_ydbdr_lf libcolour_ydbdr_lf_t;
	typedef struct libcolour_ydbdr_llf libcolour_ydbdr_llf_t;

.fi
These
.BR struct s
use
.BR float ,
.BR double ,
and
.BR long\ double ,
respecitively, for the values stored in them,
and are otherwise identical.
.B struct libcolour_ydbdr_f
is defined as
.nf

	struct libcolour_ydbdr_f {
		enum libcolour_model \fImodel\fP;
		float \fIY\fP;
		float \fIDb\fP;
		float \fIDr\fP;
	};

.fi
.I .model
shall be set to
.BR LIBCOLOUR_YDBDR .
In
.BR union\ libcolour_colour_f ,
.BR union\ libcolour_colour_lf ,
and
.BR union\ libcolour_colour_llf ,
.I .ydbdr
is used for YDbDr colours.
.P
.IR .Y ,
.IR .Db ,
and
.I .Dr
hold the Y (luma), Db, and Dr values, respectively.
.P
Y is 0 in black and 1 in white.
Db is the difference (with a factor) between Y and blue.
Dr is the difference (with a factor) between Y and red.
.P
YDbDr is additive, since it is linearly isomorphic
to CIE 1931 XYZ. It's white point is the
CIE Standard Illuminant D65. Additionally, conversion
between YDbDr and YUV is done with a diagonal matrix
multiplication.
.SH SEE ALSO
.BR libcolour (7)
.SH AUTHORS
Mattias Andrée
.RI < maandree@kth.se >