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.\" ========================================================================
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.IX Title "Graphics::Toolkit::Color::Value 3pm"
.TH Graphics::Toolkit::Color::Value 3pm "2023-01-30" "perl v5.36.0" "User Contributed Perl Documentation"
.\" For nroff, turn off justification.  Always turn off hyphenation; it makes
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.SH "NAME"
Graphics::Toolkit::Color::Value \- check, convert and measure color values
.SH "SYNOPSIS"
.IX Header "SYNOPSIS"
.Vb 2
\&    use Graphics::Toolkit::Color::Value;         # import nothing
\&    use Graphics::Toolkit::Color::Value \*(Aq:all\*(Aq;  # import all routines
\&    
\&    check_rgb( 256, 10, 12 ); # throws error 255 is the limit
\&    my @hsl = hsl_from_rgb( 20, 50, 70 ); # convert from RGB to HSL space
.Ve
.SH "DESCRIPTION"
.IX Header "DESCRIPTION"
A set of helper routines to handle \s-1RGB\s0 and \s-1HSL\s0 values: bound checks, 
conversion, measurement. Most subs expect three numerical values, 
or sometimes two triplet. This module is supposed to be used by
Graphics::Toolkit::Color and not directly.
.SH "ROUTINES"
.IX Header "ROUTINES"
.SS "check_rgb"
.IX Subsection "check_rgb"
Carp error message if \s-1RGB\s0 value triplet is not valid (or out of value range).
.SS "check_hsl"
.IX Subsection "check_hsl"
Carp error message if \s-1HSL\s0 value triplet is not valid (or out of value range).
.SS "trim_rgb"
.IX Subsection "trim_rgb"
Change \s-1RGB\s0 triplet to the nearest valid values.
.SS "trim_hsl"
.IX Subsection "trim_hsl"
Change \s-1HSL\s0 triplet to the nearest valid values.
.SS "hsl_from_rgb"
.IX Subsection "hsl_from_rgb"
Converting an rgb value triplet into the corresponding hsl
.PP
Red, Green and Blue are integer in 0 .. 255.
Hue is an integer between 0 .. 359 (hue) 
and saturation and lightness are 0 .. 100 (percentage).
A hue of 360 and 0 (degree in a cylindrical coordinate system) is
considered to be the same, this modul deals only with the ladder.
.SS "rgb_from_hsl"
.IX Subsection "rgb_from_hsl"
Converting an hsl value triplet into the corresponding rgb 
(see rgb_from_name and hsl_from_name). Please not that back and forth
conversion can lead to drifting results due to rounding.
.PP
.Vb 4
\&    my @rgb = rgb_from_hsl( 0, 90, 50 );
\&    my @rgb = rgb_from_hsl( [0, 90, 50] ); # works too
\&    # for real (none integer results), any none zero value works as second arg 
\&    my @rgb = rgb_from_hsl( [0, 90, 50], \*(Aqreal\*(Aq);
.Ve
.SS "hex_from_rgb"
.IX Subsection "hex_from_rgb"
Converts a red green blue triplet into format: '#RRGGBB'.
.SS "rgb_from_hex"
.IX Subsection "rgb_from_hex"
Converts '#RRGGBB' or '#RGB' hex values into regular \s-1RGB\s0 triple of 0..255.
.SS "distance_rgb"
.IX Subsection "distance_rgb"
Distance in (linear) rgb color space between two coordinates.
.PP
.Vb 1
\&    my $d = distance_rgb([1,1,1], [2,2,2]);  # approx 1.7
.Ve
.SS "distance_hsl"
.IX Subsection "distance_hsl"
Distance in (cylindrical) hsl color space between two coordinates.
.PP
.Vb 1
\&    my $d = distance_rgb([1,1,1], [356, 3, 2]); # approx 6
.Ve
.SH "COPYRIGHT & LICENSE"
.IX Header "COPYRIGHT & LICENSE"
Copyright 2022 Herbert Breunung.
.PP
This program is free software; you can redistribute it and/or modify it 
under same terms as Perl itself.
.SH "AUTHOR"
.IX Header "AUTHOR"
Herbert Breunung, <lichtkind@cpan.org>