NAME

Imager::Color::Float - Rough floating point sample color handling

SYNOPSIS

$color = Imager::Color->new($red, $green, $blue);
$color = Imager::Color->new($red, $green, $blue, $alpha);
$color = Imager::Color->new("#C0C0FF"); # html color specification

$color->set($red, $green, $blue);
$color->set($red, $green, $blue, $alpha);
$color->set("#C0C0FF"); # html color specification

($red, $green, $blue, $alpha) = $color->rgba();
@hsv = $color->hsv(); # not implemented but proposed
my $c8 = $color->as_8bit;

$color->info();

DESCRIPTION

This module handles creating color objects used by Imager. The idea is that in the future this module will be able to handle color space calculations as well.

A floating point Imager color consists of up to four components, each in the range 0.0 to 1.0. Unfortunately the meaning of the components can change depending on the type of image you're dealing with:

• for 3 or 4 channel images the color components are red, green, blue, alpha.

• for 1 or 2 channel images the color components are gray, alpha, with the other two components ignored.

An alpha value of zero is fully transparent, an alpha value of 1.0 is fully opaque.

METHODS

new

This creates a color object to pass to functions that need a color argument.

set

This changes an already defined color. Note that this does not affect any places where the color has been used previously.

rgba()

This returns the red, green, blue and alpha channels of the color the object contains.

info

Calling info merely dumps the relevant color to the log.

red

green

blue

alpha

Returns the respective component as a floating point value typically from 0 to 1.0.

as_8bit

Returns the color as the roughly equivalent 8-bit Imager::Color object. Samples below zero or above 1.0 are clipped.

as_css_rgb

Formats the color as a CSS rgb() style color. If the color is closely representable as byte style syntax, eg rgb(255, 128, 128), it will be returned in that form, otherwise the samples are formatted as percentages with up to 2 decimal places.

Setting colors

The new() and set() methods can accept the following parameters:

• an Imager::Color::Float object

• an Imager::Color object, the ranges of samples are translated from 0...255 to 0.0...1.0.

• 3 values, treated as red, green, blue

• 4 values, treated as red, green, blue, alpha

• an 8 character hex color, optionally preceded by #.

• a 6 character hex color, optionally preceded by #.

• a CSS rgb() color, based on CSS Color 4. The none keyword is not supported and numbers must be simple decimals without exponents. eg.

  rgb(50% 50% 100%)
  rgb(0, 0, 255)
  rgb(0.5 0.5 1.0 / 0.8)
  rgb(50%, 50%, 100%, 80%)

  This accepts some colors not accepted by the CSS rgb() specification, this may change.

AUTHOR

Arnar M. Hrafnkelsson, addi@umich.edu And a great deal of help from others - see the README for a complete list.

SEE ALSO

Imager(3), Imager::Color.

http://imager.perl.org/