Add ability to transpose text object coordinates.

lib/pdf-reader-turtletext.rb

@@ -1,6 +1,7 @@
 require 'pdf-reader'
 require 'pdf/reader/patch/object_hash'
 require 'pdf/reader/positional_text_receiver'
+require 'pdf/reader/transposed_positional_text_receiver'
 
 require 'pdf/reader/turtletext'
 require 'pdf/reader/turtletext/version'

lib/pdf/reader/transposed_positional_text_receiver.rb

@@ -0,0 +1,31 @@
+# Receiver to access positional (x,y) text content from a PDF
+#
+# Typical usage:
+#
+#   reader = PDF::Reader.new(filename)
+#   receiver = PDF::Reader::TransposedPositionalTextReceiver.new
+#   reader.page(page).walk(receiver)
+#   receiver.content
+#
+class PDF::Reader::TransposedPositionalTextReceiver < PDF::Reader::PositionalTextReceiver
+
+  # record text that is drawn on the page
+  def show_text(string) # Tj
+    raise PDF::Reader::MalformedPDFError, "current font is invalid" if @state.current_font.nil?
+    newx, newy = @state.trm_transform(0,0)
+    @content[newx] ||= {}
+    @content[newx][newy] ||= ''
+    @content[newx][newy] << @state.current_font.to_utf8(string)
+  end
+
+  # override PageTextReceiver content accessor .
+  # Returns a hash of positional text:
+  #   {
+  #     x_coord=>{y_coord=>text, y_coord=>text },
+  #     x_coord=>{y_coord=>text, y_coord=>text }
+  #   }
+  def content
+    super
+  end
+
+end

lib/pdf/reader/turtletext.rb

@@ -18,6 +18,7 @@ class PDF::Reader::Turtletext
   # +source+ is a file name or stream-like object
   # Supported +options+ include:
   # * :y_precision
+  # * :transpose_coordinates
   def initialize(source, options={})
     @options = options
     @reader = PDF::Reader.new(source)
@@ -32,6 +33,14 @@ def y_precision
     options[:y_precision] ||= 3
   end
 
+  # Returns whether or not the coordinates of the text objects are transposed.
+  # This is an option specified at object creation time that will essentially swap
+  # X and Y coordinates of all the text objects. This can improve the structured content
+  # if the PDF document is oriented in landscape.
+  def coordinates_transposed?
+    options[:transpose_coordinates] ||= false
+  end
+
   # Returns positional (with fuzzed y positioning) text content collection as a hash:
   #   [ fuzzed_y_position, [[x_position,content]] ]
   def content(page=1)
@@ -153,7 +162,9 @@ def bounding_box(&block)
   private
 
     def load_content(page)
-      receiver = PDF::Reader::PositionalTextReceiver.new
+      receiver = (coordinates_transposed? ?
+        PDF::Reader::TransposedPositionalTextReceiver.new :
+        PDF::Reader::PositionalTextReceiver.new)
       reader.page(page).walk(receiver)
       receiver.content
     end