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diff --git a/LIBCOLOUR_CIEXYY.7 b/LIBCOLOUR_CIEXYY.7 new file mode 100644 index 0000000..989b170 --- /dev/null +++ b/LIBCOLOUR_CIEXYY.7 @@ -0,0 +1,64 @@ +.TH LIBCOLOUR_CIEXYY 7 libcolour +.SH NAME +LIBCOLOUR_CIEXYY - CIE xyY +.SH DESCRIPTION +CIE xyY colours are presented with either of +.nf + + \fBtypedef struct libcolour_ciexyy_f libcolour_ciexyy_f_t;\fP + \fBtypedef struct libcolour_ciexyy_lf libcolour_ciexyy_lf_t;\fP + \fBtypedef struct libcolour_ciexyy_llf libcolour_ciexyy_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_ciexyy_f +is defined as +.nf + + \fBstruct libcolour_ciexyy_f {\fP + \fBenum libcolour_model\fP \fImodel\fP\fB;\fP + \fBfloat\fP \fIx\fP\fB;\fP + \fBfloat\fP \fIy\fP\fB;\fP + \fBfloat\fP \fIY\fP\fB;\fP + \fB};\fP + +.fi +.I .model +shall be set to +.BR LIBCOLOUR_CIEXYY . +In +.BR union\ libcolour_colour_f , +.BR union\ libcolour_colour_lf , +and +.BR union\ libcolour_colour_llf , +.I .ciexyy +is used for CIE xyY colours. +.P +.IR .x , +.IR .y , +and +.I .Y +hold the unscaled x, y, and Y values, respectively. +.P +CIE xyY is not additive, nor is it linearily +isomorphic to CIE 1931 XYZ. Rather, it is defined by +x = X/(X + Y + Z), y = Y/(X + Y + Z), where X, Y, and +Z are the CIE 1931 XYZ values (with the same names) +for the same colour. The value Y is the same in both +colour models. +.P +This colour model is derived from CIE 1931 XYZ and +is primarily used for representing chromaticities. +.SH SEE ALSO +.BR libcolour (7) +.SH AUTHORS +Mattias Andrée +.RI < maandree@kth.se > |