Class: Tb::PNMWriter

Inherits:

Object

• Object
• Tb::PNMWriter

Defined in:

lib/tb/pnm.rb

Instance Method Summary

• #finish ⇒ Object
• #header_generator=(gen) ⇒ Object
• #header_required? ⇒ Boolean
• #initialize(io) ⇒ PNMWriter constructor

  A new instance of PNMWriter.

• #put_hash(pairs) ⇒ Object

Constructor Details

#initialize(io) ⇒ PNMWriter

Returns a new instance of PNMWriter.

# File 'lib/tb/pnm.rb', line 172

def initialize(io)
  @io = io
  @ary = []
  @fields = {}
end

Instance Method Details

#finish ⇒ Object

# File 'lib/tb/pnm.rb', line 192

def finish
  undefined_field = ['x', 'y', 'component', 'value'] - @fields.keys
  if !undefined_field.empty?
    raise ArgumentError, "field not defined: #{undefined_field.inspect[1...-1]}"
  end
  pnm_type = nil
  width = height = nil
  comments = []
  max_value = nil
  max_x = max_y = 0
  values = { 0.0 => true, 1.0 => true }
  components = {}
  @ary.each {|rec|
    case rec['component']
    when 'pnm_type'
      pnm_type = rec['value']
    when 'width'
      width = rec['value'].to_i
    when 'height'
      height = rec['value'].to_i
    when 'max'
      max_value = rec['value'].to_i
    when 'comment'
      comments << rec['value']
    when 'R', 'G', 'B', 'V'
      components[rec['component']] = true
      x = rec['x'].to_i
      y = rec['y'].to_i
      max_x = x if max_x < x
      max_y = y if max_y < y
      values[rec['value'].to_f] = true
    end
  }
  if !(components.keys - %w[V]).empty? &&
     !(components.keys - %w[R G B]).empty?
    raise ArgumentError, "inconsistent color component: #{components.keys.sort.inspect[1...-1]}"
  end
  case pnm_type
  when 'P1', 'P4' then raise ArgumentError, "unexpected compoenent for PBM: #{components.keys.sort.inspect[1...-1]}" if !(components.keys - %w[V]).empty?
  when 'P2', 'P5' then raise ArgumentError, "unexpected compoenent for PGM: #{components.keys.sort.inspect[1...-1]}" if !(components.keys - %w[V]).empty?
  when 'P3', 'P6' then raise ArgumentError, "unexpected compoenent for PPM: #{components.keys.sort.inspect[1...-1]}" if !(components.keys - %w[R G B]).empty?
  end
  comments.each {|c|
    if /[\r\n]/ =~ c
      raise ArgumentError, "comment cannot contain a newline: #{c.inspect}"
    end
  }
  if !width
    width = max_x + 1
  end
  if !height
    height = max_y + 1
  end
  if !max_value
    min_interval = 1.0
    values.keys.sort.each_cons(2) {|v1, v2|
      d = v2-v1
      min_interval = d if d < min_interval
    }
    if min_interval < 0.0039 # 1/255 = 0.00392156862745098...
      max_value = 0xffff
    elsif min_interval < 1.0 || !(components.keys & %w[R G B]).empty?
      max_value = 0xff
    else
      max_value = 1
    end
  end
  if pnm_type
    if !pnm_type.kind_of?(String) || /\AP[123456]\z/ !~ pnm_type
      raise ArgumentError, "unexpected PNM type: #{pnm_type.inspect}"
    end
  else
    if (components.keys - ['V']).empty?
      if max_value == 1
        pnm_type = 'P4' # PBM
      else
        pnm_type = 'P5' # PGM
      end
    else
      pnm_type = 'P6' # PPM
    end
  end
  header = "#{pnm_type}\n"
  comments.each {|c| header << '#' << c << "\n" }
  header << "#{width} #{height}\n"
  header << "#{max_value}\n" if /P[2536]/ =~ pnm_type
  if /P[14]/ =~ pnm_type # PBM
    max_value = 1
  end
  bytes_per_component = bytes_per_line = component_fmt = component_template = nil
  case pnm_type
  when 'P1' then bytes_per_component = 1; raster = '1' * (width * height)
  when 'P4' then bytes_per_line = (width + 7) / 8; raster = ["1"*width].pack("B*") * height
  when 'P2' then bytes_per_component = max_value.to_s.length+1; component_fmt = "%#{bytes_per_component}d"; raster = (component_fmt % 0) * (width * height)
  when 'P5' then bytes_per_component, component_template = max_value < 0x100 ? [1, 'C'] : [2, 'n']; raster = "\0" * (bytes_per_component * width * height)
  when 'P3' then bytes_per_component = max_value.to_s.length+1; component_fmt = "%#{bytes_per_component}d"; raster = (component_fmt % 0) * (3 * width * height)
  when 'P6' then bytes_per_component, component_template = max_value < 0x100 ? [1, 'C'] : [2, 'n']; raster = "\0" * (bytes_per_component * 3 * width * height)
  else
    raise
  end
  raster.force_encoding("ASCII-8BIT") if raster.respond_to? :force_encoding
  @ary.each {|rec|
    c = rec['component']
    next if /\A[RGBV]\z/ !~ c
    x = rec['x'].to_i
    y = rec['y'].to_i
    next if x < 0 || width <= x
    next if y < 0 || height <= y
    v = rec['value'].to_f
    if v < 0
      v = 0
    elsif 1 < v
      v = 1
    end
    case pnm_type
    when 'P1'
      v = v < 0.5 ? '1' : '0'
      raster[y * width + x] = v
    when 'P4'
      xhi, xlo = x.divmod(8)
      i = y * bytes_per_line + xhi
      byte = raster[i].ord
      if v < 0.5
        byte |= 0x80 >> xlo
      else
        byte &= 0xff7f >> xlo
      end
      raster[i] = [byte].pack("C")
    when 'P2'
      v = (v * max_value).round
      raster[(y * width + x) * bytes_per_component, bytes_per_component] = component_fmt % v
    when 'P5'
      v = (v * max_value).round
      raster[(y * width + x) * bytes_per_component, bytes_per_component] = [v].pack(component_template)
    when 'P3'
      v = (v * max_value).round
      i = (y * width + x) * 3
      if c == 'G' then i += 1
      elsif c == 'B' then i += 2
      end
      raster[i * bytes_per_component, bytes_per_component] = component_fmt % v
    when 'P6'
      v = (v * max_value).round
      i = (y * width + x) * 3
      if c == 'G' then i += 1
      elsif c == 'B' then i += 2
      end
      raster[i * bytes_per_component, bytes_per_component] = [v].pack(component_template)
    else
      raise
    end
  }
  if pnm_type == 'P1'
    raster.gsub!(/[01]{#{width}}/, "\\&\n")
    if 70 < width
      raster.gsub!(/[01]{70}/, "\\&\n")
    end
    raster << "\n" if /\n\z/ !~ raster
  elsif /P[23]/ =~ pnm_type
    components_per_line = /P2/ =~ pnm_type ? width : 3 * width
    raster.gsub!(/  +/, ' ')
    raster.gsub!(/( \d+){#{components_per_line}}/, "\\&\n")
    raster.gsub!(/(\A|\n) +/, '\1')
    raster.gsub!(/.{71,}\n/) {
      $&.gsub(/(.{1,69})[ \n]/, "\\1\n")
    }
    raster << "\n" if /\n\z/ !~ raster
  end
  @io << (header+raster)
end

#header_generator=(gen) ⇒ Object

# File 'lib/tb/pnm.rb', line 182

def header_generator=(gen)
end

#header_required? ⇒ Boolean

Returns:

• (Boolean)

# File 'lib/tb/pnm.rb', line 178

def header_required?
  false
end

#put_hash(pairs) ⇒ Object

# File 'lib/tb/pnm.rb', line 185

def put_hash(pairs)
  @ary << pairs
  pairs.each {|k, v|
    @fields[k] = true
  }
end