Class: PSD::LayerMask

Inherits:
Object
  • Object
show all
Includes:
Section
Defined in:
lib/psd/layer_mask.rb

Overview

Covers parsing the global mask and controls parsing of all the layers/folders in the document.

Instance Attribute Summary collapse

Attributes included from Section

#section_end, #section_start

Instance Method Summary collapse

Methods included from Section

#end_of_section, #end_section, #start_of_section, #start_section

Constructor Details

#initialize(file, header, options) ⇒ LayerMask

Store a reference to the file and the header and initialize the defaults.



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# File 'lib/psd/layer_mask.rb', line 10

def initialize(file, header, options)
  @file = file
  @header = header
  @options = options

  @layers = []
  @merged_alpha = false
  @global_mask = nil
  @extras = []
end

Instance Attribute Details

#global_mask ⇒ Object (readonly)

Returns the value of attribute global_mask.



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# File 'lib/psd/layer_mask.rb', line 7

def global_mask
  @global_mask
end

#layers ⇒ Object (readonly)

Returns the value of attribute layers.



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# File 'lib/psd/layer_mask.rb', line 7

def layers
  @layers
end

Instance Method Details

#export(outfile) ⇒ Object

Export the mask and all the children layers to a file.



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# File 'lib/psd/layer_mask.rb', line 77

def export(outfile)
  if @layers.size == 0
    # No data, just read whatever's here.
    return outfile.write @file.read(@section_end[:all] - start_of_section)
  end

  # Read the initial mask data since it won't change
  outfile.write @file.read(@layer_section_start - @file.tell)

  @layers.reverse.each do |layer|
    layer.export(outfile)
  end

  outfile.write @file.read(end_of_section - @file.tell)
end

#parse ⇒ Object

Parse this section, including all of the layers and folders. Once implemented, this will also trigger parsing of the channel images for each layer.



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# File 'lib/psd/layer_mask.rb', line 30

def parse
  start_section

  mask_size = @file.read_int
  finish = @file.tell + mask_size

  return self if mask_size <= 0

  layer_info_size = Util.pad2(@file.read_int)

  if layer_info_size > 0
    layer_count = @file.read_short

    if layer_count < 0
      layer_count = layer_count.abs
      @merged_alpha = true
    end

    if layer_count * (18 + 6 * @header.channels) > layer_info_size
      raise "Unlikely number of layers parsed: #{layer_count}"
    end

    @layer_section_start = @file.tell
    layer_count.times do
      @layers << PSD::Layer.new(@file).parse
    end

    layers.each do |layer|
      @file.seek 8, IO::SEEK_CUR and next if layer.folder? || layer.folder_end?
      layer.parse_channel_image!(@header, @options[:parse_layer_images])
    end
  end

  # Layers are parsed in reverse order
  layers.reverse!
  group_layers

  parse_global_mask

  # Ensure we're at the end of this section
  @file.seek finish
  end_section

  return self
end

#skip ⇒ Object

Allows us to skip this section because it starts with the length of the section stored as an integer.



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# File 'lib/psd/layer_mask.rb', line 23

def skip
  @file.seek @file.read_int, IO::SEEK_CUR
  return self
end