diff options
author | Mattias Andrée <maandree@member.fsf.org> | 2016-01-05 17:36:57 +0100 |
---|---|---|
committer | Mattias Andrée <maandree@member.fsf.org> | 2016-01-05 17:36:57 +0100 |
commit | cec8b9e5d3cd8d4da977b643bb5c9391a80334d2 (patch) | |
tree | 09c65b8cba39fcadd6fd93e8c964961207933bb7 /doc | |
parent | m (diff) | |
download | libred-cec8b9e5d3cd8d4da977b643bb5c9391a80334d2.tar.gz libred-cec8b9e5d3cd8d4da977b643bb5c9391a80334d2.tar.bz2 libred-cec8b9e5d3cd8d4da977b643bb5c9391a80334d2.tar.xz |
add libred_get_colour.3
Signed-off-by: Mattias Andrée <maandree@member.fsf.org>
Diffstat (limited to '')
-rw-r--r-- | doc/man/libred_get_colour.3 | 93 |
1 files changed, 93 insertions, 0 deletions
diff --git a/doc/man/libred_get_colour.3 b/doc/man/libred_get_colour.3 new file mode 100644 index 0000000..5220067 --- /dev/null +++ b/doc/man/libred_get_colour.3 @@ -0,0 +1,93 @@ +.TH LIBRED_GET_COLOUR 3 LIBRED +.SH NAME +libred_get_colour \- Calculate a colour temperature +.SH SYNOPSIS +.nf +#include <libred.h> + +int \fBlibred_get_colour\fP(long int \fItemp\fP, double* \fIr\fP, double* \fIg\fP, double* \fIb\fP); +.fi +.PP +Link with +.IR -lred . +.SH DESCRIPTION +.B libred_get_colour +gets or interpolates the colour temperature for +.I temp +kelvins, and returns the colour temperature in sRGB. The values, +between 0.0 and 1.0, for the "red", green, and blue channels +are stored in +.IR *r , +.IR *g , +and +.IR *b , +respectively. +.PP +At least one of the values will be 1.0, none will be greater than +1.0, and none will be less than 0.0. It is guaranteed (unless the +resources file has been modified) that +.IR *r , +.IR *g , +and +.I *b +all will be 1.0 if +.I temp +is 6500. +.PP +You must call +.BR libred_init_colour (3) +before the first use of this function, +and you should call +.BR libred_term_colour (3) +after the last use of this function. +.SH "RETURN VALUE" +Upon successful completion, the function returns 0. On failure, +the function returns -1 and sets +.B errno +appropriately. +.SH ERRORS +The function may fail if: +.TP +.B EOVERFLOW +The colour temperature lookup table is smaller than it should be. +.TP +.B EDOM +If +.I temp +is less than +.B LIBRED_LOWEST_TEMPERATURE +(which is 1000.) +.PP +The function may also fail for any reason specified for +.BR pread (3), +and set the value of +.B errno +to the same values. +.B errno +is always set to 0 on success. +.SH "FUTURE DIRECTIONS" +It is possible that the behaviour is changed to loading the +colour temperature lookup table rather than just open a +file descriptor to it. +.SH "SEE ALSO" +.BR libred.h (0), +.BR libred (7), +.BR libred_init_colour (3), +.BR libred_term_colour (3) +.SH LICENSE +Copyright \(co 2016 Mattias Andrée +.br +License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>. +.br +This is free software: you are free to change and redistribute it. +.br +There is NO WARRANTY, to the extent permitted by law. +.PP +Copying and distribution of this manual, with or without modification, +are permitted in any medium without royalty provided the copyright +notice and this notice are preserved. This file is offered as-is, +without any warranty. +.SH BUGS +Please report bugs to <https://github.com/maandree/libred/issues> +or to <maandree@member.fsf.org>. + |