Module: Retouch::Kernels

Defined in:
lib/retouch/kernels/lut.rb,
lib/retouch/kernels/color.rb,
lib/retouch/kernels/convolve.rb

Defined Under Namespace

Modules: Convolve, LUT

Class Method Summary collapse

Class Method Details

.quantize(image, colors: 256, dither: :none, palette: nil) ⇒ Object 



7
8
9
10
11
12
13
14
15
16
 
# File 'lib/retouch/kernels/color.rb', line 7

def quantize(image, colors: 256, dither: :none, palette: nil)
  indices, palette = Tessel::Quantize.quantize(image, colors: Integer(colors), dither: dither.to_sym, palette:)
  source = image.bytes
  output = String.new(capacity: source.bytesize, encoding: Encoding::BINARY)
  (image.width * image.height).times do |index|
    red, green, blue = palette.fetch(indices.getbyte(index))
    output << red << green << blue << source.getbyte((index * 4) + 3)
  end
  Tessel::Image.from_rgba(image.width, image.height, output, metadata: image.metadata)
end