Class: Axon::AlphaStripper

Inherits:
Object
  • Object
show all
Defined in:
lib/axon/alpha_stripper.rb

Overview

Strips the Alpha Channel from an Image

Axon::AlphaStripper Removes the Alpha Channel from an Image.

Example

Instance Method Summary collapse

Constructor Details

#initialize(source) ⇒ AlphaStripper

:call-seq:

AlphaStripper.new(image_in)

Removes the alpha channel from image_in.



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# File 'lib/axon/alpha_stripper.rb', line 17

def initialize(source)
  @source = source
end

Instance Method Details

#components ⇒ Object

Gets the components in the image.



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# File 'lib/axon/alpha_stripper.rb', line 35

def components
  case @source.components
  when 2 then 1
  when 4 then 3
  else @source.components
  end
end

#gets ⇒ Object

Gets the next scanline from the image.



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# File 'lib/axon/alpha_stripper.rb', line 51

def gets
  sl = @source.gets
  return unless sl

  # This should probably be done in C, but not seeing alpha stripping
  # performance as terribly important right now.
  case @source.components
  when 2
    (sl.size / 2).times{ |i| sl.slice!(1) }
    sl
  when 4
    (sl.size / 4).times{ |i| sl.slice!(3) }
    sl
  else
    sl
  end
end

#height ⇒ Object

Gets the height of the image. Same as the height of the source image.



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# File 'lib/axon/alpha_stripper.rb', line 23

def height
  @source.height
end

#lineno ⇒ Object

Gets the line number of the next scanline.



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# File 'lib/axon/alpha_stripper.rb', line 45

def lineno
  @source.lineno
end

#width ⇒ Object

Gets the width of the image. Same as the width of the source image.



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# File 'lib/axon/alpha_stripper.rb', line 29

def width
  @source.width
end