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Convert::Color::HSL(3)User Contributed Perl DocumentatioConvert::Color::HSL(3)

NAME
       "Convert::Color::HSL" - a color value represented as
       hue/saturation/lightness

SYNOPSIS
       Directly:

	use Convert::Color::HSL;

	my $red = Convert::Color::HSL->new( 0, 1, 0.5 );

	# Can also parse strings
	my $pink = Convert::Color::HSL->new( '0,1,0.8' );

       Via Convert::Color:

	use Convert::Color;

	my $cyan = Convert::Color->new( 'hsl:300,1,0.5' );

DESCRIPTION
       Objects in this class represent a color in HSL space, as a set of three
       floating-point values. Hue is stored as a value in degrees, in the
       range 0 to 360 (exclusive). Saturation and lightness are in the range 0
       to 1.

       This color space may be considered as a cylinder, of height and radius
       1. Hue represents the position of the color as the angle around the
       axis, the saturation as the distance from the axis, and the lightness
       the height above the base. In this shape, the entire base of the
       cylinder is pure black, the axis through the centre represents the
       range of greys, and the entire top of the cylinder is pure white. The
       circumference of the circular cross-section midway along the axis
       contains the pure-saturated color wheel.

       Because both surfaces of this cylinder contain pure black or white
       discs, a closely-related color space can be created by reshaping the
       cylinder into a bi-cone such that the top and bottom of the cylinder
       become single points. The radius from the axis of this shape is called
       the chroma (though this is a different definition of "chroma" than that
       used by CIE).

       While the components of this space are called Hue-Chroma-Lightness, it
       should not be confused with the similarly-named Hue-Chroma-Luminance
       (HCL) space.

CONSTRUCTOR
   $color = Convert::Color::HSL->new( $hue, $saturation, $lightness )
       Returns a new object to represent the set of values given. The hue
       should be in the range 0 to 360 (exclusive), and saturation and
       lightness should be between 0 and 1. Values outside of these ranges
       will be clamped.

   $color = Convert::Color::HSL->new( $string )
       Parses $string for values, and construct a new object similar to the
       above three-argument form. The string should be in the form

	hue,saturation,lightnes

       containing the three floating-point values in decimal notation.

METHODS
   $h = $color->hue
   $s = $color->saturation
   $v = $color->lightness
       Accessors for the three components of the color.

   $c = $color->chroma
       Returns the derived property of "chroma", which maps the color space
       onto a bicone instead of a cylinder. This more closely measures the
       intuitive concept of how "colorful" the color is than the saturation
       value and is useful for distance calculations.

   ( $hue, $saturation, $lightness ) = $color->hsl
       Returns the individual hue, saturation and lightness components of the
       color value.

   $measure = $color->dst_hsl( $other )
       Returns a measure of the distance between the two colors. This is the
       Euclidean distance between the two colors as points in the chroma-
       adjusted cone space.

   $measure = $color->dst_hsl_cheap( $other )
       Returns a measure of the distance between the two colors. This is used
       in the calculation of "dst_hsl" but since it omits the final square-
       root and scaling it is cheaper to calculate, for use in cases where
       only the relative values matter, such as when picking the "best match"
       out of a set of colors. It ranges between 0 for identical colors and 4
       for the distance between complementary pure-saturated colors.

SEE ALSO
       ·   Convert::Color - color space conversions

       ·   Convert::Color::RGB - a color value represented as red/green/blue

       ·   <http://en.wikipedia.org/wiki/HSL_and_HSV> - HSL and HSV on
	   Wikipedia

AUTHOR
       Paul Evans <leonerd@leonerd.org.uk>

perl v5.18.2			  2014-05-13		Convert::Color::HSL(3)
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