Class: Color::RGB

Class | Color::RGB
In: | lib/color.rb lib/color/rgb-colors.rb lib/color/rgb.rb
Parent: | Object

An RGB colour object.

### Methods

+ - == adjust_brightness adjust_hue adjust_saturation b b= blue blue= blue_p blue_p= brightness css_hsl css_hsla css_rgb css_rgba darken_by from_fraction from_html from_percentage g g= green green= green_p green_p= html inspect lighten_by max_rgb_as_grayscale max_rgb_as_greyscale mix_with new pdf_fill pdf_stroke r r= red red= red_p red_p= to_cmyk to_grayscale to_greyscale to_hsl to_rgb to_yiq

### Classes and Modules

Module Color::RGB::Metallic

### Constants

AliceBlue | = | Color::RGB.new(0xf0, 0xf8, 0xff)
AntiqueWhite | = | Color::RGB.new(0xfa, 0xeb, 0xd7)
Aqua | = | Color::RGB.new(0x00, 0xff, 0xff)
Aquamarine | = | Color::RGB.new(0x7f, 0xff, 0xd4)
Azure | = | Color::RGB.new(0xf0, 0xff, 0xff)
Beige | = | Color::RGB.new(0xf5, 0xf5, 0xdc)
Bisque | = | Color::RGB.new(0xff, 0xe4, 0xc4)
Black | = | Color::RGB.new(0, 0, 0)
BlanchedAlmond | = | Color::RGB.new(0xff, 0xeb, 0xcd)
Blue | = | Color::RGB.new(0x00, 0x00, 0xff)
BlueViolet | = | Color::RGB.new(0x8a, 0x2b, 0xe2)
Brown | = | Color::RGB.new(0xa5, 0x2a, 0x2a)
BurlyWood | = | Color::RGB.new(0xde, 0xb8, 0x87)
Burlywood | = | BurlyWood
CadetBlue | = | Color::RGB.new(0x5f, 0x9e, 0xa0)
Carnation | = | Color::RGB.new(0xff, 0x5e, 0xd0)
Cayenne | = | Color::RGB.new(0x8d, 0x00, 0x00)
Chartreuse | = | Color::RGB.new(0x7f, 0xff, 0x00)
Chocolate | = | Color::RGB.new(0xd2, 0x69, 0x1e)
Coral | = | Color::RGB.new(0xff, 0x7f, 0x50)
CornflowerBlue | = | Color::RGB.new(0x64, 0x95, 0xed)
Cornsilk | = | Color::RGB.new(0xff, 0xf8, 0xdc)
Crimson | = | Color::RGB.new(0xdc, 0x14, 0x3c)
Cyan | = | Color::RGB.new(0x00, 0xff, 0xff)
DarkBlue | = | Color::RGB.new(0x00, 0x00, 0x8b)
DarkCyan | = | Color::RGB.new(0x00, 0x8b, 0x8b)
DarkGoldenRod | = | Color::RGB.new(0xb8, 0x86, 0x0b)
DarkGoldenrod | = | DarkGoldenRod
DarkGray | = | Color::RGB.new(0xa9, 0xa9, 0xa9)
DarkGreen | = | Color::RGB.new(0x00, 0x64, 0x00)
DarkGrey | = | DarkGray
DarkKhaki | = | Color::RGB.new(0xbd, 0xb7, 0x6b)
DarkMagenta | = | Color::RGB.new(0x8b, 0x00, 0x8b)
DarkOliveGreen | = | Color::RGB.new(0x55, 0x6b, 0x2f)
DarkOrange | = | Color::RGB.new(0xff, 0x8c, 0x00)
DarkOrchid | = | Color::RGB.new(0x99, 0x32, 0xcc)
DarkRed | = | Color::RGB.new(0x8b, 0x00, 0x00)
DarkSalmon | = | Color::RGB.new(0xe9, 0x96, 0x7a)
DarkSeaGreen | = | Color::RGB.new(0x8f, 0xbc, 0x8f)
DarkSlateBlue | = | Color::RGB.new(0x48, 0x3d, 0x8b)
DarkSlateGray | = | Color::RGB.new(0x2f, 0x4f, 0x4f)
DarkSlateGrey | = | DarkSlateGray
DarkTurquoise | = | Color::RGB.new(0x00, 0xce, 0xd1)
DarkViolet | = | Color::RGB.new(0x94, 0x00, 0xd3)
DarkoliveGreen | = | DarkOliveGreen
Darkorange | = | Color::RGB.new(0xff, 0x8c, 0x00)
Darksalmon | = | DarkSalmon
DeepPink | = | Color::RGB.new(0xff, 0x14, 0x93)
DeepSkyBlue | = | Color::RGB.new(0x00, 0xbf, 0xbf)
DimGray | = | Color::RGB.new(0x69, 0x69, 0x69)
DimGrey | = | DimGray
DodgerBlue | = | Color::RGB.new(0x1e, 0x90, 0xff)
Feldspar | = | Color::RGB.new(0xd1, 0x92, 0x75)
FireBrick | = | Color::RGB.new(0xb2, 0x22, 0x22)
Firebrick | = | FireBrick
FloralWhite | = | Color::RGB.new(0xff, 0xfa, 0xf0)
ForestGreen | = | Color::RGB.new(0x22, 0x8b, 0x22)
Fuchsia | = | Color::RGB.new(0xff, 0x00, 0xff)
Gainsboro | = | Color::RGB.new(0xdc, 0xdc, 0xdc)
GhostWhite | = | Color::RGB.new(0xf8, 0xf8, 0xff)
Gold | = | Color::RGB.new(0xff, 0xd7, 0x00)
GoldenRod | = | Color::RGB.new(0xda, 0xa5, 0x20)
Goldenrod | = | GoldenRod
Gray | = | Color::RGB.new(0x80, 0x80, 0x80)
Gray10 | = | Color::RGB.from_percentage(10, 10, 10)
Gray20 | = | Color::RGB.from_percentage(20, 20, 20)
Gray30 | = | Color::RGB.from_percentage(30, 30, 30)
Gray40 | = | Color::RGB.from_percentage(40, 40, 40)
Gray50 | = | Color::RGB.from_percentage(50, 50, 50)
Gray60 | = | Color::RGB.from_percentage(60, 60, 60)
Gray70 | = | Color::RGB.from_percentage(70, 70, 70)
Gray80 | = | Color::RGB.from_percentage(80, 80, 80)
Gray90 | = | Color::RGB.from_percentage(90, 90, 90)
Green | = | Color::RGB.new(0x00, 0x80, 0x00)
GreenYellow | = | Color::RGB.new(0xad, 0xff, 0x2f)
Grey | = | Gray
Grey10 | = | Gray10
Grey20 | = | Gray20
Grey30 | = | Gray30
Grey40 | = | Gray40
Grey50 | = | Gray50
Grey60 | = | Gray60
Grey70 | = | Gray70
Grey80 | = | Gray80
Grey90 | = | Gray90
HoneyDew | = | Color::RGB.new(0xf0, 0xff, 0xf0)
Honeydew | = | HoneyDew
HotPink | = | Color::RGB.new(0xff, 0x69, 0xb4)
IndianRed | = | Color::RGB.new(0xcd, 0x5c, 0x5c)
Indigo | = | Color::RGB.new(0x4b, 0x00, 0x82)
Ivory | = | Color::RGB.new(0xff, 0xff, 0xf0)
Khaki | = | Color::RGB.new(0xf0, 0xe6, 0x8c)
Lavender | = | Color::RGB.new(0xe6, 0xe6, 0xfa)
LavenderBlush | = | Color::RGB.new(0xff, 0xf0, 0xf5)
LawnGreen | = | Color::RGB.new(0x7c, 0xfc, 0x00)
LemonChiffon | = | Color::RGB.new(0xff, 0xfa, 0xcd)
LightBlue | = | Color::RGB.new(0xad, 0xd8, 0xe6)
LightCoral | = | Color::RGB.new(0xf0, 0x80, 0x80)
LightCyan | = | Color::RGB.new(0xe0, 0xff, 0xff)
LightGoldenRodYellow | = | Color::RGB.new(0xfa, 0xfa, 0xd2)
LightGoldenrodYellow | = | LightGoldenRodYellow
LightGray | = | Color::RGB.new(0xd3, 0xd3, 0xd3)
LightGreen | = | Color::RGB.new(0x90, 0xee, 0x90)
LightGrey | = | LightGray
LightPink | = | Color::RGB.new(0xff, 0xb6, 0xc1)
LightSalmon | = | Color::RGB.new(0xff, 0xa0, 0x7a)
LightSeaGreen | = | Color::RGB.new(0x20, 0xb2, 0xaa)
LightSkyBlue | = | Color::RGB.new(0x87, 0xce, 0xfa)
LightSlateBlue | = | Color::RGB.new(0x84, 0x70, 0xff)
LightSlateGray | = | Color::RGB.new(0x77, 0x88, 0x99)
LightSlateGrey | = | LightSlateGray
LightSteelBlue | = | Color::RGB.new(0xb0, 0xc4, 0xde)
LightYellow | = | Color::RGB.new(0xff, 0xff, 0xe0)
Lightsalmon | = | LightSalmon
LightsteelBlue | = | LightSteelBlue
Lime | = | Color::RGB.new(0x00, 0xff, 0x00)
LimeGreen | = | Color::RGB.new(0x32, 0xcd, 0x32)
Linen | = | Color::RGB.new(0xfa, 0xf0, 0xe6)
Magenta | = | Color::RGB.new(0xff, 0x00, 0xff)
Maroon | = | Color::RGB.new(0x80, 0x00, 0x00)
MediumAquaMarine | = | Color::RGB.new(0x66, 0xcd, 0xaa)
MediumAquamarine | = | MediumAquaMarine
MediumBlue | = | Color::RGB.new(0x00, 0x00, 0xcd)
MediumOrchid | = | Color::RGB.new(0xba, 0x55, 0xd3)
MediumPurple | = | Color::RGB.new(0x93, 0x70, 0xdb)
MediumSeaGreen | = | Color::RGB.new(0x3c, 0xb3, 0x71)
MediumSlateBlue | = | Color::RGB.new(0x7b, 0x68, 0xee)
MediumSpringGreen | = | Color::RGB.new(0x00, 0xfa, 0x9a)
MediumTurquoise | = | Color::RGB.new(0x48, 0xd1, 0xcc)
MediumVioletRed | = | Color::RGB.new(0xc7, 0x15, 0x85)
MidnightBlue | = | Color::RGB.new(0x19, 0x19, 0x70)
MintCream | = | Color::RGB.new(0xf5, 0xff, 0xfa)
MistyRose | = | Color::RGB.new(0xff, 0xe4, 0xe1)
Moccasin | = | Color::RGB.new(0xff, 0xe4, 0xb5)
NavajoWhite | = | Color::RGB.new(0xff, 0xde, 0xad)
Navy | = | Color::RGB.new(0x00, 0x00, 0x80)
OldLace | = | Color::RGB.new(0xfd, 0xf5, 0xe6)
Olive | = | Color::RGB.new(0x80, 0x80, 0x00)
OliveDrab | = | Color::RGB.new(0x6b, 0x8e, 0x23)
Olivedrab | = | OliveDrab
Orange | = | Color::RGB.new(0xff, 0xa5, 0x00)
OrangeRed | = | Color::RGB.new(0xff, 0x45, 0x00)
Orchid | = | Color::RGB.new(0xda, 0x70, 0xd6)
PaleGoldenRod | = | Color::RGB.new(0xee, 0xe8, 0xaa)
PaleGoldenrod | = | PaleGoldenRod
PaleGreen | = | Color::RGB.new(0x98, 0xfb, 0x98)
PaleTurquoise | = | Color::RGB.new(0xaf, 0xee, 0xee)
PaleVioletRed | = | Color::RGB.new(0xdb, 0x70, 0x93)
PapayaWhip | = | Color::RGB.new(0xff, 0xef, 0xd5)
PeachPuff | = | Color::RGB.new(0xff, 0xda, 0xb9)
Peachpuff | = | PeachPuff
Peru | = | Color::RGB.new(0xcd, 0x85, 0x3f)
Pink | = | Color::RGB.new(0xff, 0xc0, 0xcb)
Plum | = | Color::RGB.new(0xdd, 0xa0, 0xdd)
PowderBlue | = | Color::RGB.new(0xb0, 0xe0, 0xe6)
Purple | = | Color::RGB.new(0x80, 0x00, 0x80)
Red | = | Color::RGB.new(0xff, 0x00, 0x00)
RosyBrown | = | Color::RGB.new(0xbc, 0x8f, 0x8f)
RoyalBlue | = | Color::RGB.new(0x41, 0x69, 0xe1)
SaddleBrown | = | Color::RGB.new(0x8b, 0x45, 0x13)
Salmon | = | Color::RGB.new(0xfa, 0x80, 0x72)
SandyBrown | = | Color::RGB.new(0xf4, 0xa4, 0x60)
SeaGreen | = | Color::RGB.new(0x2e, 0x8b, 0x57)
SeaShell | = | Color::RGB.new(0xff, 0xf5, 0xee)
Seashell | = | SeaShell
Sienna | = | Color::RGB.new(0xa0, 0x52, 0x2d)
Silver | = | Color::RGB.new(0xc0, 0xc0, 0xc0)
SkyBlue | = | Color::RGB.new(0x87, 0xce, 0xeb)
SlateBlue | = | Color::RGB.new(0x6a, 0x5a, 0xcd)
SlateGray | = | Color::RGB.new(0x70, 0x80, 0x90)
SlateGrey | = | SlateGray
Snow | = | Color::RGB.new(0xff, 0xfa, 0xfa)
SpringGreen | = | Color::RGB.new(0x00, 0xff, 0x7f)
SteelBlue | = | Color::RGB.new(0x46, 0x82, 0xb4)
Tan | = | Color::RGB.new(0xd2, 0xb4, 0x8c)
Teal | = | Color::RGB.new(0x00, 0x80, 0x80)
Thistle | = | Color::RGB.new(0xd8, 0xbf, 0xd8)
Tomato | = | Color::RGB.new(0xff, 0x63, 0x47)
Turquoise | = | Color::RGB.new(0x40, 0xe0, 0xd0)
Violet | = | Color::RGB.new(0xee, 0x82, 0xee)
VioletRed | = | Color::RGB.new(0xd0, 0x20, 0x90)
Wheat | = | Color::RGB.new(0xf5, 0xde, 0xb3)
White | = | Color::RGB.new(0xff, 0xff, 0xff)
WhiteSmoke | = | Color::RGB.new(0xf5, 0xf5, 0xf5)
Yellow | = | Color::RGB.new(0xff, 0xff, 0x00)
YellowGreen | = | Color::RGB.new(0x9a, 0xcd, 0x32)
PDF_FORMAT_STR | = | "%.3f %.3f %.3f %s" |  | The format of a DeviceRGB colour for PDF. In color-tools 2.0 this will be removed from this package and added back as a modification by the PDF::Writer package.

### Public Class methods

from_fraction(r = 0.0, g = 0.0, b = 0.0)

Creates an RGB colour object from fractional values 0..1.

      Color::RGB.from_fraction(.3, .2, .1)

from_html(html_colour)

Creates an RGB colour object from an HTML colour descriptor (e.g., `"fed"` or `"cabbed;"`.

      Color::RGB.from_html("fed")
      Color::RGB.from_html("#fed")
      Color::RGB.from_html("#cabbed")
      Color::RGB.from_html("cabbed")

from_percentage(r = 0, g = 0, b = 0)

Creates an RGB colour object from percentages 0..100.

      Color::RGB.from_percentage(10, 20 30)

new(r = 0, g = 0, b = 0)

Creates an RGB colour object from the standard range 0..255.

      Color::RGB.new(32, 64, 128)
      Color::RGB.new(0x20, 0x40, 0x80)

### Public Instance methods

+(other)

Adds another colour to the current colour. The other colour will be converted to RGB before addition. This conversion depends upon a to_rgb method on the other colour.

The addition is done using the RGB Accessor methods to ensure a valid colour in the result.

-(other)

Subtracts another colour to the current colour. The other colour will be converted to RGB before subtraction. This conversion depends upon a to_rgb method on the other colour.

The subtraction is done using the RGB Accessor methods to ensure a valid colour in the result.

==(other)

Compares the other colour to this one. The other colour will be converted to RGB before comparison, so the comparison between a RGB colour and a non-RGB colour will be approximate and based on the other colour‘s default to_rgb conversion. If there is no to_rgb conversion, this will raise an exception. This will report that two RGB colours are equivalent if all component values are within COLOR_TOLERANCE of each other.

adjust_brightness(percent)

Returns a new colour with the brightness adjusted by the specified percentage. Negative percentages will darken the colour; positive percentages will brighten the colour.

      Color::RGB::DarkBlue.adjust_brightness(10)
      Color::RGB::DarkBlue.adjust_brightness(-10)

adjust_hue(percent)

Returns a new colour with the hue adjusted by the specified percentage. Negative percentages will reduce the hue; positive percentages will increase the hue.

      Color::RGB::DarkBlue.adjust_hue(10)
      Color::RGB::DarkBlue.adjust_hue(-10)

adjust_saturation(percent)

Returns a new colour with the saturation adjusted by the specified percentage. Negative percentages will reduce the saturation; positive percentages will increase the saturation.

      Color::RGB::DarkBlue.adjust_saturation(10)
      Color::RGB::DarkBlue.adjust_saturation(-10)

b()

Returns the blue component of the colour as a fraction in the range 0.0 .. 1.0.

b=(bb)

Sets the blue component of the colour as a fraction in the range 0.0 .. 1.0.

blue()

Returns the blue component of the colour in the normal 0 .. 255 range.

blue=(bb)

Sets the blue component of the colour in the normal 0 .. 255 range.

blue_p()

Returns the blue component of the colour as a percentage.

blue_p=(bb)

Sets the blue component of the colour as a percentage.

brightness()

Returns the brightness value for a colour, a number between 0..1. Based on the Y value of YIQ encoding, representing luminosity, or perceived brightness.

This may be modified in a future version of color-tools to use the luminosity value of HSL.

css_hsl()

Present the colour as an HSL HTML/CSS colour string (e.g., "hsl(180, 25%, 35%)"). Note that this will perform a to_hsl operation using the default conversion formula.

css_hsla()

Present the colour as an HSLA (with alpha) HTML/CSS colour string (e.g., "hsla(180, 25%, 35%, 1)"). Note that this will perform a to_hsl operation using the default conversion formula.

css_rgb()

Present the colour as an RGB HTML/CSS colour string (e.g., "rgb(0%, 50%, 100%)"). Note that this will perform a to_rgb operation using the default conversion formula.

css_rgba()

Present the colour as an RGBA (with alpha) HTML/CSS colour string (e.g., "rgb(0%, 50%, 100%, 1)"). Note that this will perform a to_rgb operation using the default conversion formula.

darken_by(percent)

Mix the RGB hue with Black so that the RGB hue is the specified percentage of the resulting colour. Strictly speaking, this isn‘t a darken_by operation.

g()

Returns the green component of the colour as a fraction in the range 0.0 .. 1.0.

g=(gg)

Sets the green component of the colour as a fraction in the range 0.0 .. 1.0.

green()

Returns the green component of the colour in the normal 0 .. 255 range.

green=(gg)

Sets the green component of the colour in the normal 0 .. 255 range.

green_p()

Returns the green component of the colour as a percentage.

green_p=(gg)

Sets the green component of the colour as a percentage.

html()

Present the colour as an HTML/CSS colour string.

inspect()
lighten_by(percent)

Mix the RGB hue with White so that the RGB hue is the specified percentage of the resulting colour. Strictly speaking, this isn‘t a darken_by operation.

max_rgb_as_grayscale()

Retrieve the maxmum RGB value from the current colour as a GrayScale colour

max_rgb_as_greyscale()

Alias for max_rgb_as_grayscale

mix_with(mask, opacity)

Mix the mask colour (which must be an RGB object) with the current colour at the stated opacity percentage (0..100).

pdf_fill()

Present the colour as a DeviceRGB fill colour string for PDF. This will be removed from the default package in color-tools 2.0.

pdf_stroke()

Present the colour as a DeviceRGB stroke colour string for PDF. This will be removed from the default package in color-tools 2.0.

r()

Returns the red component of the colour as a fraction in the range 0.0 .. 1.0.

r=(rr)

Sets the red component of the colour as a fraction in the range 0.0 .. 1.0.

red()

Returns the red component of the colour in the normal 0 .. 255 range.

red=(rr)

Sets the red component of the colour in the normal 0 .. 255 range.

red_p()

Returns the red component of the colour as a percentage.

red_p=(rr)

Sets the red component of the colour as a percentage.

to_cmyk()

Converts the RGB colour to CMYK. Most colour experts strongly suggest that this is not a good idea (some even suggesting that it‘s a very bad idea). CMYK represents additive percentages of inks on white paper, whereas RGB represents mixed colour intensities on a black screen.

However, the colour conversion can be done. The basic method is multi-step:

1. Convert the R, G, and B components to C, M, and Y components.

        c = 1.0 - r
        m = 1.0 - g
        y = 1.0 - b

2. Compute the minimum amount of black (K) required to smooth the colour in inks.

        k = min(c, m, y)

3. Perform undercolour removal on the C, M, and Y components of the colours because less of each colour is needed for each bit of black. Also, regenerate the black (K) based on the undercolour removal so that the colour is more accurately represented in ink.

        c = min(1.0, max(0.0, c - UCR(k)))
        m = min(1.0, max(0.0, m - UCR(k)))
        y = min(1.0, max(0.0, y - UCR(k)))
        k = min(1.0, max(0.0, BG(k)))

The undercolour removal function and the black generation functions return a value based on the brightness of the RGB colour.

to_grayscale()

Convert to grayscale.

to_greyscale()

Alias for to_grayscale

to_hsl()

Returns the HSL colour encoding of the RGB value. The conversions here are based on forumlas from www.easyrgb.com/math.php and elsewhere.

to_rgb(ignored = nil)
to_yiq()

Returns the YIQ (NTSC) colour encoding of the RGB value.

[Validate]