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diff --git a/LIBCOLOUR_CIE1960UCS.7 b/LIBCOLOUR_CIE1960UCS.7 new file mode 100644 index 0000000..95dff79 --- /dev/null +++ b/LIBCOLOUR_CIE1960UCS.7 @@ -0,0 +1,67 @@ +.TH LIBCOLOUR_CIE1960UCS 7 libcolour +.SH NAME +LIBCOLOUR_CIE1960UCS - CIE 1960 UCS +.SH DESCRIPTION +CIE 1960 UCS +colours are presented with either of +.nf + + \fBtypedef struct libcolour_cie1960ucs_f libcolour_cie1960ucs_f_t;\fP + \fBtypedef struct libcolour_cie1960ucs_lf libcolour_cie1960ucs_lf_t;\fP + \fBtypedef struct libcolour_cie1960ucs_llf libcolour_cie1960ucs_llf_t;\fP + +.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_cie1960ucs_f +is defined as +.nf + + \fBstruct libcolour_cie1960ucs_f {\fP + \fBenum libcolour_model\fP \fImodel\fP\fB;\fP + \fBfloat\fP \fIu\fP\fB;\fP + \fBfloat\fP \fIv\fP\fB;\fP + \fBfloat\fP \fIY\fP\fB;\fP + \fB};\fP + +.fi +.I .model +shall be set to +.BR LIBCOLOUR_CIE1960UCS . +In +.BR union\ libcolour_colour_f , +.BR union\ libcolour_colour_lf , +and +.BR union\ libcolour_colour_llf , +.I .cie1960ucs +is used for CIE 1960 UCS colours. +.P +.IR .u , +.IR .v , +and +.I .Y +hold the u, v, and, Y (luma) values. +.P +Y is 0 in black and 1 in white. +u is defined as 4X / (X + 15Y + 3Z), and +v is defined as 6X / (X + 15Y + 3Z), where +X, Y, and Z are CIE 1931 XYZ values. +.P +The Y value is not part of CIE 1960 UCS, +but is added, and borrowed from CIE 1931 XYZ +and CIE xyY, so that colours of all lumas +can be specified. +.P +CIE 1960 UCS is not additive. +.SH SEE ALSO +.BR libcolour (7) +.SH AUTHORS +Mattias Andrée +.RI < maandree@kth.se > |