Class: SwfRuby::Swf::BitsLossless2

Inherits:
Object
  • Object
show all
Defined in:
lib/swf_ruby/swf/bits_lossless2.rb

Constant Summary collapse

ShiftDepth = 
Magick::QuantumDepth - 8
MaxRGB = 
2 ** Magick::QuantumDepth - 1

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(image_bytearray) ⇒ BitsLossless2

Returns a new instance of BitsLossless2.



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# File 'lib/swf_ruby/swf/bits_lossless2.rb', line 11

def initialize(image_bytearray)
  image = Magick::Image.from_blob(image_bytearray).first
  data = ""
  data.force_encoding("ASCII-8BIT") if data.respond_to? :force_encoding
  @format = nil
  colormap = []
  # creating colormap to check number of colors
  image.get_pixels(0, 0, image.columns, image.rows).each_with_index do |pixel,i|
    break if colormap.length > 255
    idx = colormap.index(pixel)
    if idx
      data << [idx].pack("C")
    else
      colormap << pixel
      data << [colormap.length-1].pack("C")
    end
    if (i+1) % image.columns == 0
      # padding
      data += [0].pack("C") * (4-image.columns&3)
    end
  end

  # checking image format by size of colormap
  if colormap.length > 255
    # format=5
    # reset and re-build data_stream without colopmap
    data = ""
    image.get_pixels(0, 0, image.columns, image.rows).each_with_index do |pixel,i|
      opacity = (MaxRGB-pixel.opacity) >> ShiftDepth
      data += [opacity].pack("C")
      data += [pixel.red >> ShiftDepth].pack("C")
      data += [pixel.green >> ShiftDepth].pack("C")
      data += [pixel.blue >> ShiftDepth].pack("C")
    end
    @format = 5
  else
    # format=3
    # added colormap before data_stream
    data = colormap.inject("") { |r,c|
      opacity = (MaxRGB-c.opacity) >> ShiftDepth
      if opacity == 0
        r +=
          [0].pack("C") +
          [0].pack("C") +
          [0].pack("C") +
          [opacity].pack("C")
      else
        r +=
          [c.red >> ShiftDepth].pack("C") +
          [c.green >> ShiftDepth].pack("C") +
          [c.blue >> ShiftDepth].pack("C") +
          [opacity].pack("C")
      end
    } + data
    @format = 3
    @color_table_size = colormap.length-1
  end

  @width = image.columns
  @height = image.rows
  @zlib_bitmap_data = Zlib::Deflate.deflate(data)
end

Instance Attribute Details

#color_table_size ⇒ Object

Returns the value of attribute color_table_size.



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# File 'lib/swf_ruby/swf/bits_lossless2.rb', line 6

def color_table_size
  @color_table_size
end

#format ⇒ Object

Returns the value of attribute format.



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# File 'lib/swf_ruby/swf/bits_lossless2.rb', line 6

def format
  @format
end

#height ⇒ Object

Returns the value of attribute height.



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# File 'lib/swf_ruby/swf/bits_lossless2.rb', line 6

def height
  @height
end

#width ⇒ Object

Returns the value of attribute width.



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# File 'lib/swf_ruby/swf/bits_lossless2.rb', line 6

def width
  @width
end

#zlib_bitmap_data ⇒ Object

Returns the value of attribute zlib_bitmap_data.



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# File 'lib/swf_ruby/swf/bits_lossless2.rb', line 6

def zlib_bitmap_data
  @zlib_bitmap_data
end