Class: BMPDecoder

Inherits:
Object
  • Object
show all
Defined in:
lib/ruby-doom.rb

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(filename, debug = false) ⇒ BMPDecoder

Returns a new instance of BMPDecoder.



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# File 'lib/ruby-doom.rb', line 134

def initialize(filename, debug=false)
  @debug = debug
  @filename = filename
  @scale_factor = 1
  @thinning_factor = 5
end

Instance Attribute Details

#bit_planes ⇒ Object (readonly)

Returns the value of attribute bit_planes.



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# File 'lib/ruby-doom.rb', line 132

def bit_planes
  @bit_planes
end

#bits_per_pixel ⇒ Object (readonly)

Returns the value of attribute bits_per_pixel.



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# File 'lib/ruby-doom.rb', line 132

def bits_per_pixel
  @bits_per_pixel
end

#colors_important ⇒ Object (readonly)

Returns the value of attribute colors_important.



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# File 'lib/ruby-doom.rb', line 132

def colors_important
  @colors_important
end

#colors_used ⇒ Object (readonly)

Returns the value of attribute colors_used.



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# File 'lib/ruby-doom.rb', line 132

def colors_used
  @colors_used
end

#compression ⇒ Object (readonly)

Returns the value of attribute compression.



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# File 'lib/ruby-doom.rb', line 132

def compression
  @compression
end

#height ⇒ Object (readonly)

Returns the value of attribute height.



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# File 'lib/ruby-doom.rb', line 132

def height
  @height
end

#info_header_size ⇒ Object (readonly)

Returns the value of attribute info_header_size.



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# File 'lib/ruby-doom.rb', line 132

def info_header_size
  @info_header_size
end

#offset_to_image_data ⇒ Object (readonly)

Returns the value of attribute offset_to_image_data.



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# File 'lib/ruby-doom.rb', line 132

def offset_to_image_data
  @offset_to_image_data
end

#scale_factor ⇒ Object

Returns the value of attribute scale_factor.



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# File 'lib/ruby-doom.rb', line 133

def scale_factor
  @scale_factor
end

#size ⇒ Object (readonly)

Returns the value of attribute size.



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# File 'lib/ruby-doom.rb', line 132

def size
  @size
end

#size_of_image ⇒ Object (readonly)

Returns the value of attribute size_of_image.



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# File 'lib/ruby-doom.rb', line 132

def size_of_image
  @size_of_image
end

#thinning_factor ⇒ Object

Returns the value of attribute thinning_factor.



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# File 'lib/ruby-doom.rb', line 133

def thinning_factor
  @thinning_factor
end

#type ⇒ Object (readonly)

Returns the value of attribute type.



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# File 'lib/ruby-doom.rb', line 132

def type
  @type
end

#width ⇒ Object (readonly)

Returns the value of attribute width.



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# File 'lib/ruby-doom.rb', line 132

def width
  @width
end

#xpixels_per_meter ⇒ Object (readonly)

Returns the value of attribute xpixels_per_meter.



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# File 'lib/ruby-doom.rb', line 132

def xpixels_per_meter
  @xpixels_per_meter
end

#ypixels_per_meter ⇒ Object (readonly)

Returns the value of attribute ypixels_per_meter.



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# File 'lib/ruby-doom.rb', line 132

def ypixels_per_meter
  @ypixels_per_meter
end

Instance Method Details

#decode ⇒ Object 



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# File 'lib/ruby-doom.rb', line 140

def decode
  # hm, wouldn't File.read(filename, "rb") do this?
  bytes = []
  File.open(@filename, "r").each_byte {|x| bytes << x }
  
  # decode BITMAPFILEHEADER 
  @type = decode_word(bytes.slice(0,2))
  raise "Can only decode bitmaps" unless @type == 19778

  @size = decode_dword(bytes.slice(2,4))
  res1 = decode_word(bytes.slice(6,2))
  res1 = decode_word(bytes.slice(8,2))
  @offset_to_image_data = decode_dword(bytes.slice(10,4))
  
  # decode BITMAPINFOHEADER
  @info_header_size = decode_dword(bytes.slice(14,4))
  @width = decode_dword(bytes.slice(18,4)) # specified as a LONG... but DWORD works... (?)
  @height = decode_dword(bytes.slice(22,4)) #  specified as a LONG... but DWORD works... (?)
  @bit_planes = decode_word(bytes.slice(26,2))
  @bits_per_pixel = decode_word(bytes.slice(28,2))
  raise "Can't process bitmaps with more than one bit per pixel.  Save it as a monochrome bitmap to fix this." unless @bits_per_pixel == 1

  @compression = decode_dword(bytes.slice(30,4))
  raise "Can't process compressed bitmaps" unless @compression == 0

  @size_of_image = decode_dword(bytes.slice(34,4))
  @xpixels_per_meter = decode_dword(bytes.slice(38,4)) # specified as a LONG... but DWORD works... (?)
  @ypixels_per_meter = decode_dword(bytes.slice(42,4)) # specified as a LONG... but DWORD works... (?)
  @colors_used = decode_dword(bytes.slice(46,4))
  @colors_important = decode_dword(bytes.slice(50,4))
  
  # color table - assume monochrome bitmap for now
  rgb1 = RGBQuad.new(bytes.slice(54,4))
  rgb2 = RGBQuad.new(bytes.slice(58,4))

  @raw_image = bytes.slice(62, bytes.size-62)
  self
end

#decode_dword(bytes) ⇒ Object 



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# File 'lib/ruby-doom.rb', line 192

def decode_dword(bytes)
  bytes.pack("C4").unpack("L")[0] 
end

#decode_word(bytes) ⇒ Object 



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# File 'lib/ruby-doom.rb', line 189

def decode_word(bytes)
  bytes.pack("C2").unpack("S")[0] 
end

#line ⇒ Object 



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# File 'lib/ruby-doom.rb', line 182

def line
  PointsToLine.new(raw_points, @debug).line
end

#raw_points ⇒ Object 



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# File 'lib/ruby-doom.rb', line 178

def raw_points
  decode if @raw_image.nil?
  ArrayToPoints.new(@width, @height, @raw_image).points
end

#thin ⇒ Object 



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# File 'lib/ruby-doom.rb', line 185

def thin
  pts = PointThinner.new(line, @thinning_factor).thin
  pts.collect {|p| p.scale(@scale_factor) }  
end