1Imager::Color(3) User Contributed Perl Documentation Imager::Color(3)
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6 Imager::Color - Color handling for Imager.
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9 use Imager;
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11 $color = Imager::Color->new($red, $green, $blue);
12 $color = Imager::Color->new($red, $green, $blue, $alpha);
13 $color = Imager::Color->new("#C0C0FF"); # html color specification
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15 $color->set($red, $green, $blue);
16 $color->set($red, $green, $blue, $alpha);
17 $color->set("#C0C0FF"); # html color specification
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19 ($red, $green, $blue, $alpha) = $color->rgba();
20 @hsv = $color->hsv();
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22 $color->info();
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24 if ($color->equals(other=>$other_color)) {
25 ...
26 }
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29 This module handles creating color objects used by Imager. The idea is
30 that in the future this module will be able to handle color space
31 calculations as well.
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33 An Imager color consists of up to four components, each in the range 0
34 to 255. Unfortunately the meaning of the components can change
35 depending on the type of image you're dealing with:
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37 • for 3 or 4 channel images the color components are red, green,
38 blue, alpha.
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40 • for 1 or 2 channel images the color components are gray, alpha,
41 with the other two components ignored.
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43 An alpha value of zero is fully transparent, an alpha value of 255 is
44 fully opaque.
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47 new This creates a color object to pass to functions that need a color
48 argument.
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50 set This changes an already defined color. Note that this does not
51 affect any places where the color has been used previously.
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53 rgba()
54 This returns the red, green, blue and alpha channels of the color
55 the object contains.
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57 info
58 Calling info merely dumps the relevant color to the log.
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60 equals(other=>$other_color)
61 equals(other=>$other_color, ignore_alpha=>1)
62 Compares $self and color $other_color returning true if the color
63 components are the same.
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65 Compares all four channels unless "ignore_alpha" is set. If
66 "ignore_alpha" is set only the first three channels are compared.
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68 You can specify colors in several different ways, you can just supply
69 simple values:
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71 • an Imager::Color object
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73 • an Imager::Color::Float object, the ranges of samples are
74 translated from 0.0...1.0 to 0...255.
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76 • simple numeric parameters - if you supply 3 or 4 numeric arguments,
77 you get a color made up of those RGB (and possibly A) components.
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79 • a six hex digit web color, either "RRGGBB" or "#RRGGBB"
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81 • an eight hex digit web color, either "RRGGBBAA" or "#RRGGBBAA".
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83 • a CSS rgb() color, based on CSS Color 4. The "none" keyword is not
84 supported and numbers must be simple decimals without exponents.
85 eg.
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87 rgb(50% 50% 100%)
88 rgb(0, 0, 255)
89 rgb(0.5 0.5 1.0 / 0.8)
90 rgb(50%, 50%, 100%, 80%)
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92 Samples from percentages or decimals are rounded up per CSS Color 3
93 and 4.
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95 This accepts some colors not accepted by the CSS rgb()
96 specification, this may change.
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98 • a 3 hex digit web color, "#RGB" - a value of F becomes 255.
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100 • a color name, from whichever of the gimp "Named_Colors" file or X
101 "rgb.txt" is found first. The same as using the "name" keyword.
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103 You can supply named parameters:
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105 • 'red', 'green' and 'blue', optionally shortened to 'r', 'g' and
106 'b'. The color components in the range 0 to 255.
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108 # all of the following are equivalent
109 my $c1 = Imager::Color->new(red=>100, blue=>255, green=>0);
110 my $c2 = Imager::Color->new(r=>100, b=>255, g=>0);
111 my $c3 = Imager::Color->new(r=>100, blue=>255, g=>0);
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113 • "hue", "saturation" and "value", optionally shortened to "h", "s"
114 and "v", to specify a HSV color. 0 <= hue < 360, 0 <= s <= 1 and 0
115 <= v <= 1.
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117 # the same as RGB(127,255,127)
118 my $c1 = Imager::Color->new(hue=>120, v=>1, s=>0.5);
119 my $c1 = Imager::Color->new(hue=>120, value=>1, saturation=>0.5);
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121 • "web", which can specify a 6 or 3 hex digit web color, in any of
122 the forms "#RRGGBB", "#RGB", "RRGGBB" or "RGB".
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124 my $c1 = Imager::Color->new(web=>'#FFC0C0'); # pale red
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126 • "gray" or "grey" which specifies a single channel, from 0 to 255.
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128 # exactly the same
129 my $c1 = Imager::Color->new(gray=>128);
130 my $c1 = Imager::Color->new(grey=>128);
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132 • "rgb" which takes a 3 member arrayref, containing each of the red,
133 green and blue values.
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135 # the same
136 my $c1 = Imager::Color->new(rgb=>[255, 100, 0]);
137 my $c1 = Imager::Color->new(r=>255, g=>100, b=>0);
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139 • "hsv" which takes a 3 member arrayref, containing each of hue,
140 saturation and value.
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142 # the same
143 my $c1 = Imager::Color->new(hsv=>[120, 0.5, 1]);
144 my $c1 = Imager::Color->new(hue=>120, v=>1, s=>0.5);
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146 • "gimp" which specifies a color from a GIMP palette file. You can
147 specify the file name of the palette file with the 'palette'
148 parameter, or let Imager::Color look in various places, typically
149 "$HOME/gimp-1.x/palettes/Named_Colors" with and without the version
150 number, and in "/usr/share/gimp/palettes/". The palette file must
151 have color names.
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153 my $c1 = Imager::Color->new(gimp=>'snow');
154 my $c1 = Imager::Color->new(gimp=>'snow', palette=>'testimg/test_gimp_pal);
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156 • "xname" which specifies a color from an X11 "rgb.txt" file. You
157 can specify the file name of the "rgb.txt" file with the "palette"
158 parameter, or let Imager::Color look in various places, typically
159 "/usr/lib/X11/rgb.txt".
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161 my $c1 = Imager::Color->new(xname=>'blue') # usually RGB(0, 0, 255)
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163 • "builtin" which specifies a color from the built-in color table in
164 Imager::Color::Table. The colors in this module are the same as
165 the default X11 "rgb.txt" file.
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167 my $c1 = Imager::Color->new(builtin=>'black') # always RGB(0, 0, 0)
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169 • "name" which specifies a name from either a GIMP palette, an X
170 "rgb.txt" file or the built-in color table, whichever is found
171 first.
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173 • 'channel0', 'channel1', etc, each of which specifies a single
174 channel. These can be abbreviated to 'c0', 'c1' etc.
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176 • 'channels' which takes an arrayref of the channel values.
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178 Optionally you can add an alpha channel to a color with the 'alpha' or
179 'a' parameter.
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181 These color specifications can be used for both constructing new colors
182 with the new() method and modifying existing colors with the set()
183 method.
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186 hsv()
187 my($h, $s, $v, $alpha) = $color->hsv();
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189 Returns the color as a Hue/Saturation/Value/Alpha tuple.
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191 red
192 green
193 blue
194 alpha
195 Returns the respective component as an integer from 0 to 255.
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197 as_float
198 Returns the color as a Imager::Color::Float object.
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200 as_css_rgb
201 Returns the color as a CSS rgb() format color. This is always
202 returned in the byte form, eg. rgb(255 128 64).
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204 If the alpha is not full coverage (255) it will be rounded if the
205 result of converting the color back to an 8 bit color would return
206 the same alpha, eg. if the color alpha is 128, it will be formatted
207 as 0.5, not as the more precise 50.2%.
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210 Arnar M. Hrafnkelsson, addi@umich.edu And a great deal of help from
211 others - see the "README" for a complete list.
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214 Imager(3), Imager::Color http://imager.perl.org/
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218perl v5.36.0 2022-07-22 Imager::Color(3)