Class: RubyPSD

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

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(path) ⇒ RubyPSD

Official documents of PSD File Format is here. www.adobe.com/devnet-apps/photoshop/fileformatashtml/PhotoshopFileFormats.htm#50577409_20023



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# File 'lib/ruby-psd.rb', line 6

def initialize(path)
  @path = path
  @width = 0
  @height = 0
  @layers = []
end

Instance Attribute Details

#height ⇒ Object

Returns the value of attribute height.



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# File 'lib/ruby-psd.rb', line 12

def height
  @height
end

#layers ⇒ Object

Returns the value of attribute layers.



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# File 'lib/ruby-psd.rb', line 12

def layers
  @layers
end

#width ⇒ Object

Returns the value of attribute width.



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# File 'lib/ruby-psd.rb', line 12

def width
  @width
end

Instance Method Details

#convert_layers_to_array(arr) ⇒ Object 



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# File 'lib/ruby-psd.rb', line 99

def convert_layers_to_array(arr)
  def pick_up_from_array(ar, prev = nil)
    ret = []
    ar.each_with_index do |a, i|
      if a.class == Array
        ret += pick_up_from_array(a)
        if prev != nil and ar[i+1].class != Array
          ret << "</Layer group>"
          prev = nil
        end
      else
        if prev != nil
          ret << "</Layer group>"
        end
        ret << a
        prev = a
      end
    end
    ret << "</Layer group>" if prev != nil
    ret
  end
  (pick_up_from_array arr).flatten.reverse
end

#generate ⇒ Object 



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# File 'lib/ruby-psd.rb', line 230

def generate
  psd = open @path, "w"
  psd.print get_file_header
  psd.print get_color_mode_data
  psd.print get_image_resources
  psd.print get_layer_and_mask_information
  psd.print get_image_data
  psd.close
end

#generate_image_data ⇒ Object 



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# File 'lib/ruby-psd.rb', line 207

def generate_image_data
  
  packet = get_packet_bytes(@width)
  channels = 4
  [
    [0x00, 0x00] * @height * channels,
    packet * @height * channels
  ]

end

#get_additional_layer_info ⇒ Object 



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# File 'lib/ruby-psd.rb', line 195

def get_additional_layer_info
  []
end

#get_art_layer_record ⇒ Object 



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# File 'lib/ruby-psd.rb', line 95

def get_art_layer_record
  get_layer_record "background", []    
end

#get_channel_image_data(layer_count) ⇒ Object 



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# File 'lib/ruby-psd.rb', line 187

def get_channel_image_data(layer_count)
  [0x00] * 8 * layer_count
end

#get_color_mode_data ⇒ Object 



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# File 'lib/ruby-psd.rb', line 27

def get_color_mode_data
  # I'm not sure about this specs so I makes it as only 4 byte length of zero
  [0x00, 0x00, 0x00, 0x00].pack("C*")
end

#get_file_header ⇒ Object 



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# File 'lib/ruby-psd.rb', line 14

def get_file_header 
[
  [0x38, 0x42, 0x50, 0x53], # Signature[4] : 8BPS
  [0x00, 0x01], #Version[2] : always it's must be 1
  [0x00, 0x00, 0x00, 0x00, 0x00, 0x00],  #Reserved[6]
  [0x00, 0x04], # The number of channels in the image, Usually it's RGBA so it will be 4 
  num2bytes(@height, 4), # Height[4]
  num2bytes(@width, 4), # Width[4]
  [0x00, 0x08], #Depth[2]: the number of bits per channel. Supported values are 1, 8, 16 and 32. opted 8bit as default.
  [0x00, 0x03] #ColorMode: opted RGB Mode(3) as default. 
].flatten.pack("C*")
end

#get_global_layer_info ⇒ Object 



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# File 'lib/ruby-psd.rb', line 191

def get_global_layer_info
  [0x00] * 4
end

#get_group_layer_record(name) ⇒ Object 



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# File 'lib/ruby-psd.rb', line 123

def get_group_layer_record(name)
  if name == "</Layer group>"
    additional_data = [
      [0x38, 0x42, 0x49, 0x4D], # Blend mode signature: '8BIM'
      [0x6c, 0x73, 0x63, 0x74], # Section divider setting 'lscr'
      [0x00, 0x00, 0x00, 0x04], # Length of this additional record
      [0x00, 0x00, 0x00, 0x03]  # Type. This is 3 = bounding section divider.
    ]
  else
    additional_data = [
      [0x38, 0x42, 0x49, 0x4D], # Blend mode signature: '8BIM'
      [0x6c, 0x73, 0x63, 0x74], # Section divider setting 'lscr'
      [0x00, 0x00, 0x00, 0x0c], # Length of this additional record. It might be 12.
      [0x00, 0x00, 0x00, 0x01], # Type. This is 1 = bounding section divider.
      # Following is only present if length = 12
      [0x38, 0x42, 0x49, 0x4D], # Blend mode signature: '8BIM'
      [0x70, 0x61, 0x73, 0x73], # Blend mode key: 'pass'   
    ]    
  end
  get_layer_record name, additional_data.flatten
end

#get_image_data ⇒ Object 



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# File 'lib/ruby-psd.rb', line 199

def get_image_data
  image_data = generate_image_data
  [
    [0x00, 0x01],
    image_data # Compression method: 1 = RLE compressed the image data starts with the byte 
  ].flatten.pack("C*")
end

#get_image_resources ⇒ Object 



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# File 'lib/ruby-psd.rb', line 32

def get_image_resources
  # I'm not sure about this specs so I makes it as only 4 byte length of zero
  [0x00, 0x00, 0x00, 0x00].pack("C*")
end

#get_key_nums(layers) ⇒ Object 



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# File 'lib/ruby-psd.rb', line 76

def get_key_nums(layers)
  ret = layers.size
  layers.each do |v|
    if v.class == Array
      ret += get_key_nums(v) - 1 
    end
  end
  ret
end

#get_layer_and_mask_information ⇒ Object 



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# File 'lib/ruby-psd.rb', line 37

def get_layer_and_mask_information
  
  layer_info = get_layer_info
  global_layer_info = get_global_layer_info
  additional_layer_info = get_additional_layer_info
  size_of_layer_and_mask_information = layer_info.size + global_layer_info.size + additional_layer_info.size
  
  [
    num2bytes(size_of_layer_and_mask_information, 4),
    layer_info,
    global_layer_info,
    additional_layer_info
  ].flatten.pack("C*")
  
end

#get_layer_counts ⇒ Object 



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# File 'lib/ruby-psd.rb', line 71

def get_layer_counts
  # 1 is the count of default art layer named "background"
  1 + (get_key_nums @layers) * 2
end

#get_layer_info ⇒ Object 



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# File 'lib/ruby-psd.rb', line 53

def get_layer_info
  
  _LAYER_COUNT_LENGTH = 2
  layer_counts = get_layer_counts
  layer_records = get_layer_records
  channel_image_data = get_channel_image_data(layer_counts)
  
  size_of_layer_info = _LAYER_COUNT_LENGTH + layer_records.size + channel_image_data.size
  
  [
    num2bytes(size_of_layer_info, 4),
    num2bytes(layer_counts, 2),
    layer_records,
    channel_image_data
  ].flatten
  
end

#get_layer_record(name, additional_data) ⇒ Object 



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# File 'lib/ruby-psd.rb', line 145

def get_layer_record (name, additional_data)
  
  pascal_name = get_pascal_name(name, 4)
  size_of_additional_data = 8 + pascal_name.size + additional_data.size
  [
    [0x00] * 16, #Rectangle containing the contents of the layer
    [0x00, 0x04], #Number of channels in the layer ( Usually it will be 4 as RGBA )
    # Channel information. Six bytes per channel, consisting of: 2 bytes for Channel ID
    # 4 bytes for length of corresponding channel data
    [0xFF, 0xFF] + [0x00, 0x00, 0x00, 0x02], #-1 = transparency
    [0x00, 0x00] + [0x00, 0x00, 0x00, 0x02], #0 = red
    [0x00, 0x01] + [0x00, 0x00, 0x00, 0x02], #1 = green
    [0x00, 0x02] + [0x00, 0x00, 0x00, 0x02], #2 = blue
    [0x38, 0x42, 0x49, 0x4D], # Blend mode signature: '8BIM'
    [0x6E, 0x6F, 0x72, 0x6D], # Blend mode key: 'norm'
    [0xFF], #Opacity. 0 = transparent ... 255 = opaque
    [0x00], #Clipping: 0 = base, 1 = non-base
    [0x08], #Flags: [00001000]
            #  bit 0 = transparency protected; 
            #  bit 1 = visible; 
            #  bit 2 = obsolete;
            #  bit 3 = 1 for Photoshop 5.0 and later, tells if bit 4 has useful information;
            #  bit 4 = pixel data irrelevant to appearance of document
    [0x00], #  Just Filler (zero)
    num2bytes(size_of_additional_data, 4),
    [0x00] * 4, # Layer mask data. It won't be.
    [0x00] * 4, # Layer blending ranges. It won't be.
    pascal_name,
    additional_data
  ].flatten
  
end

#get_layer_records ⇒ Object 



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# File 'lib/ruby-psd.rb', line 86

def get_layer_records
  art_layer_record = get_art_layer_record
  layers_array = convert_layers_to_array(@layers)
  group_layer_records = layers_array.map do |name|
    get_group_layer_record name
  end
  [art_layer_record, group_layer_records].flatten
end

#get_packet_bytes(width) ⇒ Object 



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# File 'lib/ruby-psd.rb', line 218

def get_packet_bytes(width)
  divided = width / 128
  remainder = width % 128
  ret = []
  [divided, remainder]
  divided.times do
    ret << [0x101 - 128, 0xFF]
  end
  ret << [0x101 - remainder, 0xFF]
  ret.flatten
end

#get_pascal_name(name, padding) ⇒ Object 



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

def get_pascal_name(name, padding)
  arr = name.unpack("C*")
  arr = [arr.size] + arr
  if ((arr.size % padding) > 0) 
    arr += ([0] * (padding - (arr.size % padding))) 
  end
  arr
end

#num2bytes(num, size) ⇒ Object 



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# File 'lib/ruby-psd.rb', line 243

def num2bytes (num, size)
  num.to_s(16).rjust(size*2,"0").unpack("a2"*(size)).map{|a| "0x#{a}".to_i(16)}
end

#output_psd ⇒ Object 



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# File 'lib/ruby-psd.rb', line 240

def output_psd
end

#pick_up_from_array(ar, prev = nil) ⇒ Object 



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# File 'lib/ruby-psd.rb', line 100

def pick_up_from_array(ar, prev = nil)
  ret = []
  ar.each_with_index do |a, i|
    if a.class == Array
      ret += pick_up_from_array(a)
      if prev != nil and ar[i+1].class != Array
        ret << "</Layer group>"
        prev = nil
      end
    else
      if prev != nil
        ret << "</Layer group>"
      end
      ret << a
      prev = a
    end
  end
  ret << "</Layer group>" if prev != nil
  ret
end