Imager::Color - Color handling for Imager. |
Imager::Color - Color handling for Imager.
use Imager;
$color = Imager::Color->new($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();
$color->info();
if ($color->equals(other=>$other_color)) { ... }
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.
An Imager color consists of up to four components, each in the range 0 to 255. Unfortunately the meaning of the components can change depending on the type of image you're dealing with:
An alpha value of zero is fully transparent, an alpha value of 255 is fully opaque.
rgba()
Compares all four channels unless ignore_alpha
is set. If
ignore_alpha
is set only the first three channels are compared.
You can specify colors in several different ways, you can just supply simple values:
RRGGBB
or #RRGGBB
an eight hex digit web color, either RRGGBBAA
or #RRGGBBAA
.
a 3 hex digit web color, #RGB
- a value of F becomes 255.
a color name, from whichever of the gimp Named_Colors
file or X
rgb.txt
is found first. The same as using the name
keyword.
You can supply named parameters:
# all of the following are equivalent my $c1 = Imager::Color->new(red=>100, blue=>255, green=>0); my $c2 = Imager::Color->new(r=>100, b=>255, g=>0); my $c3 = Imager::Color->new(r=>100, blue=>255, g=>0);
hue
, saturation
and value
, optionally shortened to h
, s
and
v
, to specify a HSV color. 0 <= hue < 360, 0 <= s <= 1 and 0 <= v
<= 1.
# the same as RGB(127,255,127) my $c1 = Imager::Color->new(hue=>120, v=>1, s=>0.5); my $c1 = Imager::Color->new(hue=>120, value=>1, saturation=>0.5);
web
, which can specify a 6 or 3 hex digit web color, in any of the
forms #RRGGBB
, #RGB
, RRGGBB
or RGB
.
my $c1 = Imager::Color->new(web=>'#FFC0C0'); # pale red
gray
or grey
which specifies a single channel, from 0 to 255.
# exactly the same my $c1 = Imager::Color->new(gray=>128); my $c1 = Imager::Color->new(grey=>128);
rgb
which takes a 3 member arrayref, containing each of the red,
green and blue values.
# the same my $c1 = Imager::Color->new(rgb=>[255, 100, 0]); my $c1 = Imager::Color->new(r=>255, g=>100, b=>0);
hsv
which takes a 3 member arrayref, containing each of hue,
saturation and value.
# the same my $c1 = Imager::Color->new(hsv=>[120, 0.5, 1]); my $c1 = Imager::Color->new(hue=>120, v=>1, s=>0.5);
gimp
which specifies a color from a GIMP palette file. You can
specify the file name of the palette file with the 'palette'
parameter, or let Imager::Color look in various places, typically
$HOME/gimp-1.x/palettes/Named_Colors
with and without the version
number, and in /usr/share/gimp/palettes/
. The palette file must
have color names.
my $c1 = Imager::Color->new(gimp=>'snow'); my $c1 = Imager::Color->new(gimp=>'snow', palette=>'testimg/test_gimp_pal);
xname
which specifies a color from an X11 rgb.txt
file. You can
specify the file name of the rgb.txt
file with the palette
parameter, or let Imager::Color look in various places, typically
/usr/lib/X11/rgb.txt
.
my $c1 = Imager::Color->new(xname=>'blue') # usually RGB(0, 0, 255)
builtin
which specifies a color from the built-in color table in
Imager::Color::Table. The colors in this module are the same as the
default X11 rgb.txt
file.
my $c1 = Imager::Color->new(builtin=>'black') # always RGB(0, 0, 0)
name
which specifies a name from either a GIMP palette, an X
rgb.txt
file or the built-in color table, whichever is found first.
'channel0', 'channel1', etc, each of which specifies a single channel. These can be abbreviated to 'c0', 'c1' etc.
'channels' which takes an arrayref of the channel values.
Optionally you can add an alpha channel to a color with the 'alpha' or 'a' parameter.
These color specifications can be used for both constructing new
colors with the new()
method and modifying existing colors with the
set()
method.
hsv()
my($h, $s, $v, $alpha) = $color->hsv();
Returns the color as a Hue/Saturation/Value/Alpha tuple.
Arnar M. Hrafnkelsson, addi@umich.edu
And a great deal of help from others - see the README
for a complete
list.
Imager(3), Imager::Color http://imager.perl.org/
Imager::Color - Color handling for Imager. |