Class: RRTF::ImageNode

Inherits:
Node
  • Object
show all
Defined in:
lib/rrtf/node/image_node.rb

Overview

This class represents an image within a RTF document. Currently only the PNG, JPEG and Windows Bitmap formats are supported. Efforts are made to identify the file type but these are not guaranteed to work.

Author:

  • Peter Wood

  • Wesley Hileman

Since:

  • legacy

Constant Summary

TYPE_DICTIONARY =

Supported image types.

Since:

  • legacy

{
  :png => 'pngblip',
  :jpeg => 'jpegblip',
  :bmp => 'dibitmap0' # device independent bitmap
}.freeze
SIZING_MODE_DICTIONARY =

Supported sizing modes.

Since:

  • legacy

{
  # Size the image absolutely according to the given width and height.
  "ABSOLUTE" => "ABSOLUTE",
  # Fit the image in the box specified by the given width and height,
  # preserving the aspect ratio.
  "FIX_ASPECT_RATIO" => "FIX_ASPECT_RATIO"
}.freeze

Instance Attribute Summary collapse

Attributes inherited from Node

#parent

Class Method Summary collapse

Instance Method Summary collapse

Methods inherited from Node

#is_root?, #next_node, #previous_node, #root

Constructor Details

#initialize(parent, source, id, options = {}) ⇒ ImageNode

This is the constructor for the ImageNode class.

Parameters:

  • parent (Node) —

    a reference to the node that owns the new image node.

  • source (String, File) —

    a reference to the image source; this must be a String, String URL, or a File.

  • id (Integer) —

    a unique 32-bit identifier for the image.

  • options (Hash) (defaults to: {}) —

    a hash of options.

Options Hash (options):

  • "width" (String) — default: nil —

    the display width of the image in twips (can be a string, see Utilities.value2twips).

  • "height" (String) — default: nil —

    the display height of the image in twips (can be a string, see Utilities.value2twips).

  • "sizing_mode" (String) — default: "ABSOLUTE" —

    the method used to size the image (see SIZING_MODE_DICTIONARY).

Raises:

  • (RTFError) —

    whenever the image specified is not recognised as a supported image type, something other than a String or File or IO is passed as the source parameter or if the specified source does not exist or cannot be accessed.

Since:

  • legacy



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# File 'lib/rrtf/node/image_node.rb', line 74

def initialize(parent, source, id, options = {})
   super(parent)
   @source = source
   @id     = id

   # load default options
   options = {
     "width" => nil,
     "height" => nil,
     "sizing_mode" => "ABSOLUTE",
     "border" => nil
   }.merge(options)

   # extract options
   @displayed_width    = Utilities.value2twips(options.delete("width"))
   @displayed_height   = Utilities.value2twips(options.delete("height"))
   @sizing_mode        = SIZING_MODE_DICTIONARY[options.delete("sizing_mode")]
   @border             = self.class.parse_border_array(options.delete("border"))

   # store border colours in colour table
   @border.each do |b|
     b.push_colours(root.colours)
   end

   # Store path to image.
   if @source.is_a?(String)
     begin
       @source = open(@source)
     rescue OpenURI::HTTPError => error
       response = error.io
       RTFError.fire("Could not open '#{@source}'. Server responded with #{response.status.join(',')}.")
     rescue Exception => error
       RTFError.fire("Could not open '#{@source}'. #{error.message}.")
     end # rescue block
   elsif !@source.respond_to?(:each_byte)
     RTFError.fire("A string or object that responds to :each_byte must be supplied - '#{@source}' given.")
   end # unless

   # Attempt to determine image type and dimensions.
   @type, @width, @height = self.class.inspect(@source)
   if @type.nil?
      RTFError.fire("The #{File.basename(@source)} file contains an unknown or unsupported image type.")
   elsif @width.nil? || @height.nil?
     RTFError.fire("Could not determine the dimensions of #{File.basename(@source)}.")
   end # if

   @displayed_width, @displayed_height = size_image
end

Instance Attribute Details

#border ⇒ Object

Since:

  • legacy



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# File 'lib/rrtf/node/image_node.rb', line 28

def border
  @border
end

#displayed_height ⇒ Object

Since:

  • legacy



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# File 'lib/rrtf/node/image_node.rb', line 28

def displayed_height
  @displayed_height
end

#displayed_width ⇒ Object

Since:

  • legacy



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# File 'lib/rrtf/node/image_node.rb', line 28

def displayed_width
  @displayed_width
end

#height ⇒ Object (readonly)

Since:

  • legacy



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# File 'lib/rrtf/node/image_node.rb', line 28

def height
  @height
end

#sizing_mode ⇒ Object

Since:

  • legacy



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# File 'lib/rrtf/node/image_node.rb', line 28

def sizing_mode
  @sizing_mode
end

#type ⇒ Object (readonly)

Since:

  • legacy



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# File 'lib/rrtf/node/image_node.rb', line 28

def type
  @type
end

#width ⇒ Object (readonly)

Since:

  • legacy



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# File 'lib/rrtf/node/image_node.rb', line 28

def width
  @width
end

Class Method Details

.inspect(source) ⇒ Array<Object>

Attempts to extract the type, width, and height of an image using FastImage.

Parameters:

  • source (String) —

    the file path to the source image.

Returns:

  • (Array<Object>) —

    a 3-tuple containing the type, width, and height of the image, respectively (type is a symbol, dimensions in pixels).

Since:

  • legacy



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# File 'lib/rrtf/node/image_node.rb', line 37

def self.inspect(source)
  type, width, height = nil

  type = TYPE_DICTIONARY[FastImage.type(source)]
  width, height = FastImage.size(source) unless type.nil?

  [type, width, height]
end

.parse_border_array(border) ⇒ Object

inspect()

Since:

  • legacy



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# File 'lib/rrtf/node/image_node.rb', line 46

def self.parse_border_array(border)
  case border
  when nil
    []
  when BorderStyle
    [border]
  when Hash
    [BorderStyle.new(border)]
  when Array
    border.collect{ |b| parse_border_array(b) }.flatten.compact
  else
    RTFError.fire("Invalid border #{b}.")
  end
end

Instance Method Details

#to_rtf ⇒ Object

This method generates the RTF for an ImageNode object.

Since:

  • legacy



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# File 'lib/rrtf/node/image_node.rb', line 124

def to_rtf
  text  = StringIO.new
  count = 0

  text << '{\pict'
  @border.each{ |b| text << " #{b.prefix(self.root)}" }
  text << "\\picwgoal#{@displayed_width}" if @displayed_width != nil
  text << "\\pichgoal#{@displayed_height}" if @displayed_height != nil
  text << "\\picw#{@width}\\pich#{@height}\\bliptag#{@id}"
  text << "\\#{@type}\n"

  @source.each_byte do |byte|
    hex_str = byte.to_s(16)
    hex_str.insert(0,'0') if hex_str.length == 1
    text << hex_str
    count += 1
    if count == 40
      text << "\n"
      count = 0
    end # if
  end # each_byte
  text << "\n}"

  text.string
end