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| author | Mattias Andrée <m@maandree.se> | 2025-02-03 19:31:31 +0100 |
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| committer | Mattias Andrée <m@maandree.se> | 2025-02-03 19:31:31 +0100 |
| commit | 213bff694040c995f5499072d0e8b7519837e99c (patch) | |
| tree | 8bf976ba40fd3e3256df2dec6e290bd48d611e9b /libred_get_colour.3 | |
| parent | Fix previous commit (diff) | |
| download | libred-213bff694040c995f5499072d0e8b7519837e99c.tar.gz libred-213bff694040c995f5499072d0e8b7519837e99c.tar.bz2 libred-213bff694040c995f5499072d0e8b7519837e99c.tar.xz | |
Add libred_get_colour_xy, libred_get_temperature_xy, and libred_get_temperature
Signed-off-by: Mattias Andrée <m@maandree.se>
Diffstat (limited to '')
| -rw-r--r-- | libred_get_colour.3 | 37 |
1 files changed, 35 insertions, 2 deletions
diff --git a/libred_get_colour.3 b/libred_get_colour.3 index afd0a7f..61a62ff 100644 --- a/libred_get_colour.3 +++ b/libred_get_colour.3 @@ -6,6 +6,7 @@ libred_get_colour \- Calculate a colour temperature #include <libred.h> int \fBlibred_get_colour\fP(long int \fItemp\fP, double *\fIr\fP, double *\fIg\fP, double *\fIb\fP); +int \fBlibred_get_colour_xy\fP(long int \fItemp\fP, double *\fIx\fP, double *\fIy\fP); .fi .PP Link with @@ -14,7 +15,8 @@ Link with .BR libred_get_colour () gets or interpolates the colour temperature for .I temp -kelvins, and returns the colour temperature in sRGB. The values, +kelvins, and returns the colour temperature in sRGB, with the +sRGB transfer function applied. The values, between 0.0 and 1.0, for the \(dqred\(dq, green, and blue channels are stored in .IR *r , @@ -49,14 +51,45 @@ ceiling .TP round to nearest .I (temp - LIBRED_LOWEST_TEMPERATURE + LIBRED_DELTA_TEMPERATURE / 2) / LIBRED_DELTA_TEMPERATURE * LIBRED_DELTA_TEMPERATURE + LIBRED_LOWEST_TEMPERATURE +.PP +The +.BR libred_get_colour_xy () +function is the same as the +.BR libred_get_colour () +except it uses the CIE xy colour space instead of sRGB +(of course without any transfer function). This means +that the chroma values x and y are stored in +.I *x +and +.IR *y , +and the CIE Y value shall be assumed to be 1 for +equivalence with the +.BR libred_get_colour () +function. +.PP +Neither +.IR r , +.IR g , +.IR b , +.IR x , +nor +.I y +may be +.IR NULL . .SH RETURN VALUE Upon successful completion, the .BR libred_get_colour () +and +.BR libred_get_colour_xy () function returns 0. On failure, the function returns -1 and sets .I errno to indicate the error. .SH ERRORS -The function may fail if: +The +.BR libred_get_colour () +and +.BR libred_get_colour_xy () +functions may fail if: .TP .B EDOM If |