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diff --git a/LIBCOLOUR_CIELCHUV.7 b/LIBCOLOUR_CIELCHUV.7 new file mode 100644 index 0000000..1b551c7 --- /dev/null +++ b/LIBCOLOUR_CIELCHUV.7 @@ -0,0 +1,95 @@ +.TH LIBCOLOUR_CIELCHUV 7 libcolour +.SH NAME +LIBCOLOUR_CIELCHUV - CIE LChuv +.SH DESCRIPTION +CIE LCh_uv [\(aq_\(aq denotes subscript of +subsequent characters] (also known as CIE HLC_uv) +colours are presented with either of +.nf + + \fBtypedef struct libcolour_cielchuv_f libcolour_cielchuv_f_t;\fP + \fBtypedef struct libcolour_cielchuv_lf libcolour_cielchuv_lf_t;\fP + \fBtypedef struct libcolour_cielchuv_llf libcolour_cielchuv_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_cielchuv_f +is defined as +.nf + + \fBstruct libcolour_cielchuv_f {\fP + \fBenum libcolour_model\fP \fImodel\fP\fB;\fP + \fBfloat\fP \fIL\fP\fB;\fP + \fBfloat\fP \fIC\fP\fB;\fP + \fBfloat\fP \fIh\fP\fB;\fP + \fBstruct libcolour_ciexyz\fP \fIwhite\fP\fB;\fP + \fBdouble\fP \fIone_revolution\fP\fB;\fP + \fB};\fP + +.fi +.I .model +shall be set to +.BR LIBCOLOUR_CIELCHUV . +In +.BR union\ libcolour_colour_f , +.BR union\ libcolour_colour_lf , +and +.BR union\ libcolour_colour_llf , +.I .cielchuv +is used for CIE LChuv colours. +.P +.IR .L , +.IR .C , +and +.I .h +hold the L* (luma), C*_uv (chroma), and +h_uv (hue) values, respectively, +.I .white +is the white point, and +.I .one_revolution +the The value lowest positive values of +.I .h +that is equivalent to 0. 360 if the hue is measured +in degrees, 400 if the hue is measured in gon, and +2 pi if the hue is measured radian. Any value can +be used. +.I .white +and +.I .one_revolution +are not part of the colour, but rather part of +the colour space. +.P +L* is 0 in black and 100 in white. +.P +The call +.BI libcolour_proper(& c ) +on a +.B struct libcolour_cielchuv_t +.I c +sets +.I c.white.model +to +.BR LIBCOLOUR_CIEXYZ , +and if +.I c.one_revolution +is 0, it is set to 360. +Zero is always returned in this case. +.P +CIE LCh_uv approximates uniform human colour +perception using cylindrical representation. +.P +CIE LCh_uv is not additive. It is a cylindrical +representation of CIE 1976 (L*, u*, v*). +.SH SEE ALSO +.BR libcolour (7) +.SH AUTHORS +Mattias Andrée +.RI < maandree@kth.se > |