Class: RTF::ImageNode

Inherits:
Node
  • Object
show all
Defined in:
lib/rtf/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.

Constant Summary collapse

PNG =

A definition for an image type constant.

:pngblip
JPEG =

A definition for an image type constant.

:jpegblip
BITMAP =

A definition for an image type constant.

:dibitmap0
LITTLE_ENDIAN =

A definition for an architecture endian constant.

:little
BIG_ENDIAN =

A definition for an architecture endian constant.

:big
DIMENSIONS_OFFSET =

Offsets for reading dimension data by filetype

{
  JPEG   => 2,
  PNG    => 8,
  BITMAP => 8,
}.freeze

Instance Attribute Summary collapse

Attributes inherited from Node

#parent

Instance Method Summary collapse

Methods inherited from Node

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

Constructor Details

#initialize(parent, source, id) ⇒ ImageNode

This is the constructor for the ImageNode class.

Parameters

parent

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

source

A reference to the image source. This must be a String or a File.

id

The unique identifier for the image node.

Exceptions

RTFError

Generated 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.



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# File 'lib/rtf/node.rb', line 1300

def initialize(parent, source, id)
   super(parent)
   @source = nil
   @id     = id
   @type   = nil
   @x_scaling = @y_scaling = nil
   @top_crop = @right_crop = @bottom_crop = @left_crop = nil
   @width = @height = nil
   @displayed_width = @displayed_height = nil

   # store path to image
   @source = source if source.instance_of?(String) || source.instance_of?(Tempfile)
   @source = source.path if source.instance_of?(File)

   # Check the file's existence and accessibility.
   if !File.exist?(@source)
      RTFError.fire("Unable to find the #{File.basename(@source)} file.")
   end
   if !File.readable?(@source)
      RTFError.fire("Access to the #{File.basename(@source)} file denied.")
   end

   @type = get_file_type
   if @type == nil
      RTFError.fire("The #{File.basename(@source)} file contains an "\
                    "unknown or unsupported image type.")
   end

   @width, @height = get_dimensions
end

Instance Attribute Details

#bottom_crop ⇒ Object

Attribute accessor.



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# File 'lib/rtf/node.rb', line 1279

def bottom_crop
  @bottom_crop
end

#displayed_height ⇒ Object

Attribute accessor.



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# File 'lib/rtf/node.rb', line 1279

def displayed_height
  @displayed_height
end

#displayed_width ⇒ Object

Attribute accessor.



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# File 'lib/rtf/node.rb', line 1279

def displayed_width
  @displayed_width
end

#height ⇒ Object (readonly)

Attribute accessor.



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# File 'lib/rtf/node.rb', line 1279

def height
  @height
end

#left_crop ⇒ Object

Attribute accessor.



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# File 'lib/rtf/node.rb', line 1279

def left_crop
  @left_crop
end

#right_crop ⇒ Object

Attribute accessor.



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# File 'lib/rtf/node.rb', line 1279

def right_crop
  @right_crop
end

#top_crop ⇒ Object

Attribute accessor.



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# File 'lib/rtf/node.rb', line 1279

def top_crop
  @top_crop
end

#width ⇒ Object (readonly)

Attribute accessor.



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# File 'lib/rtf/node.rb', line 1279

def width
  @width
end

#x_scaling ⇒ Object

Attribute accessor.



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# File 'lib/rtf/node.rb', line 1279

def x_scaling
  @x_scaling
end

#y_scaling ⇒ Object

Attribute accessor.



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# File 'lib/rtf/node.rb', line 1279

def y_scaling
  @y_scaling
end

Instance Method Details

#read_source(file, read, size = nil) ⇒ Object

This method loads the data for an image from its source. The method accepts two call approaches. If called without a block then the method considers the size parameter it is passed. If called with a block the method executes until the block returns true.

Parameters

size

The maximum number of bytes to be read from the file. Defaults to nil to indicate that the remainder of the file should be read in.



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# File 'lib/rtf/node.rb', line 1444

def read_source(file, read, size=nil)
   if block_given?
      done = false

      while done == false && file.eof? == false
        read << file.getbyte
         done = yield read[-1]
      end
   else
      if size != nil
         if size > 0
            total = 0
            while file.eof? == false && total < size
               read << file.getbyte
               total += 1
            end
         end
      else
         file.each_byte {|byte| read << byte}
      end
   end
end

#to_rtf ⇒ Object

This method generates the RTF for an ImageNode object.



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# File 'lib/rtf/node.rb', line 1370

def to_rtf
  text  = StringIO.new
  count = 0
  
  #text << '{\pard{\*\shppict{\pict'
  text << '{\*\shppict{\pict'
  text << "\\picscalex#{@x_scaling}" if @x_scaling != nil
  text << "\\picscaley#{@y_scaling}" if @y_scaling != nil
  text << "\\piccropl#{@left_crop}" if @left_crop != nil
  text << "\\piccropr#{@right_crop}" if @right_crop != nil
  text << "\\piccropt#{@top_crop}" if @top_crop != nil
  text << "\\piccropb#{@bottom_crop}" if @bottom_crop != nil
  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.id2name}\n"
  
  open_file do |file|
    file.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
    end
  end
  #text << "\n}}\\par}"
  text << "\n}}"

  text.string
end