Class: Color::GrayScale

Class | Color::GrayScale
In: | lib/color.rb lib/color/grayscale.rb
Parent: | Object

A colour object representing shades of grey. Used primarily in PDF document creation.

### Methods

== brightness darken_by from_fraction html lighten_by new pdf_fill pdf_stroke to_cmyk to_grayscale to_greyscale to_hsl to_rgb to_yiq

### Constants

PDF_FORMAT_STR | = | "%.3f %s" |  | The format of a DeviceGrey 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.

### Attributes

g | [RW] |

### Public Class methods

from_fraction(g = 0)

Creates a greyscale colour object from fractional values 0..1.

      Color::GreyScale.from_fraction(0.5)

new(g = 0)

Creates a greyscale colour object from percentages 0..100.

      Color::GrayScale.new(50)

### Public Instance methods

==(other)

Compares the other colour to this one. The other colour will be converted to GreyScale before comparison, so the comparison between a GreyScale colour and a non-GreyScale colour will be approximate and based on the other colour‘s to_greyscale conversion. If there is no to_greyscale conversion, this will raise an exception. This will report that two GreyScale values are equivalent if they are within 1e-4 (0.0001) of each other.

brightness()

Returns the brightness value for this greyscale value; this is the greyscale value.

darken_by(percent)

Darken the RGB hue by the stated percent.

html()

Present the colour as an HTML/CSS colour string.

lighten_by(percent)

Lightens the greyscale colour by the stated percent.

pdf_fill()

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

to_cmyk()

Convert the greyscale colour to CMYK.

to_grayscale()
to_greyscale()

Alias for to_grayscale

to_hsl()

Returns the HSL colour encoding of the greyscale value.

to_rgb(ignored = true)

Convert the greyscale colour to RGB.

to_yiq()

Returns the YIQ (NTSC) colour encoding of the greyscale value. This is an approximation, as the values for I and Q are calculated by treating the greyscale value as an RGB value. The Y (intensity or brightness) value is the same as the greyscale value.

[Validate]