Module: Tabula::TableGuesser

Defined in:
lib/tabula/table_guesser.rb

Class Method Summary collapse

Class Method Details

.euclidean_distance(x1, y1, x2, y2) ⇒ Object 



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# File 'lib/tabula/table_guesser.rb', line 65

def TableGuesser.euclidean_distance(x1, y1, x2, y2)
  return Math.sqrt( ((x1 - x2) ** 2) + ((y1 - y2) ** 2) )
end

.find_and_write_rects(filename, output_dir) ⇒ Object 



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# File 'lib/tabula/table_guesser.rb', line 8

def TableGuesser.find_and_write_rects(filename, output_dir)
  #writes to JSON the rectangles on each page in the specified PDF.
  open(File.join(output_dir, "tables.json"), 'w') do |f|
    f.write( JSON.dump(find_rects(filename).map{|a| a.map{|r| r.dims.map(&:to_i) }} ))
  end
end

.find_lines(filename) ⇒ Object 



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# File 'lib/tabula/table_guesser.rb', line 33

def TableGuesser.find_lines(filename)
  if pdf.getNumberOfPages == 0
    puts "not a pdf!"
    exit
  end

  puts "pages: " + pdf.getNumberOfPages.to_s

  lines = []
  pdf.getNumberOfPages.times do |i|
    lines << detect_lines_in_pdf_page(filename, i)
  end
  lines
end

.find_lines_on_page(pdf, page_number_zero_indexed) ⇒ Object 



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# File 'lib/tabula/table_guesser.rb', line 48

def TableGuesser.find_lines_on_page(pdf, page_number_zero_indexed)
  Tabula::Extraction::LineExtractor.lines_in_pdf_page(pdf, page_number_zero_indexed, {:render_pdf => false})
end

.find_rects(filename) ⇒ Object 



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# File 'lib/tabula/table_guesser.rb', line 15

def TableGuesser.find_rects(filename)
  pdf = load_pdfbox_pdf(filename)

  if pdf.getNumberOfPages == 0
    puts "not a pdf!"
    exit
  end

  puts "pages: " + pdf.getNumberOfPages.to_s

  tables = []
  pdf.getNumberOfPages.times do |i|
    #gotcha: with PDFView, PDF pages are 1-indexed. If you ask for page 0 and then page 1, you'll get the first page twice. So start with index 1.
    tables << find_rects_on_page(pdf, i + 1)
  end
  tables
end

.find_rects_from_lines(lines) ⇒ Object 



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# File 'lib/tabula/table_guesser.rb', line 56

def TableGuesser.find_rects_from_lines(lines)
  horizontal_lines = lines.select(&:horizontal?)
  vertical_lines = lines.select(&:vertical?)
  find_tables(vertical_lines, horizontal_lines).inject([]) do |memo, next_rect|
    java.awt.geom.Rectangle2D::Float.unionize( memo, next_rect )
  end.compact.reject{|r| r.area == 0 }.sort_by(&:area).reverse
end

.find_rects_on_page(pdf, page_index) ⇒ Object 



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# File 'lib/tabula/table_guesser.rb', line 52

def TableGuesser.find_rects_on_page(pdf, page_index)
  find_rects_from_lines(find_lines_on_page(pdf, page_index, 10))
end

.find_tables(verticals, horizontals) ⇒ Object 



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# File 'lib/tabula/table_guesser.rb', line 74

def TableGuesser.find_tables(verticals, horizontals)
  #
  # Find all the rectangles in the vertical and horizontal lines given.
  #
  # Rectangles are deduped with hashRectangle, which considers two rectangles identical if each point rounds to the same tens place as the other.
  #
  # TODO: generalize this.
  #
  corner_proximity_threshold = 0.005;

  rectangles = []
  #find rectangles with one horizontal line and two vertical lines that end within $threshold to the ends of the horizontal line.

  [true, false].each do |up_or_down_lines|
    horizontals.each do |horizontal_line|
      horizontal_line_length = horizontal_line.length

      has_vertical_line_from_the_left = false
      left_vertical_line = nil
      #for the left vertical line.
      verticals.each do |vertical_line|
        #1. if it is correctly oriented (up or down) given the outer loop here. (We don't want a false-positive rectangle with one "arm" going down, and one going up.)
        next unless is_upward_oriented(vertical_line, horizontal_line.top) == up_or_down_lines

        vertical_line_length = vertical_line.length
        longer_line_length = [horizontal_line_length, vertical_line_length].max
        corner_proximity = corner_proximity_threshold * longer_line_length
        #make this the left vertical line:
        #2. if it begins near the left vertex of the horizontal line.
        if euclidean_distance(horizontal_line.left, horizontal_line.top, vertical_line.left, vertical_line.top) < corner_proximity ||
           euclidean_distance(horizontal_line.left, horizontal_line.top, vertical_line.left, vertical_line.bottom) < corner_proximity
          #3. if it is farther to the left of the line we already have.
          if left_vertical_line.nil? || left_vertical_line.left> vertical_line.left #is this line is more to the left than left_vertical_line. #"What's your opinion on Das Kapital?"
            has_vertical_line_from_the_left = true
            left_vertical_line = vertical_line
          end
        end
      end

      has_vertical_line_from_the_right = false;
      right_vertical_line = nil
      #for the right vertical line.
      verticals.each do |vertical_line|
        next unless is_upward_oriented(vertical_line, horizontal_line.top) == up_or_down_lines
        vertical_line_length = vertical_line.length
        longer_line_length = [horizontal_line_length, vertical_line_length].max
        corner_proximity = corner_proximity_threshold * longer_line_length
        if euclidean_distance(horizontal_line.right, horizontal_line.top, vertical_line.left, vertical_line.top) < corner_proximity ||
          euclidean_distance(horizontal_line.right, horizontal_line.top, vertical_line.left, vertical_line.bottom) < corner_proximity

          if right_vertical_line.nil? || right_vertical_line.right > vertical_line.right  #is this line is more to the right than right_vertical_line. #"Can you recite all of John Galt's speech?"
            #do two passes to guarantee we don't get a horizontal line with a upwards and downwards line coming from each of its corners.
            #i.e. ensuring that both "arms" of the rectangle have the same orientation (up or down).
            has_vertical_line_from_the_right = true
            right_vertical_line = vertical_line
          end
        end
      end

      if has_vertical_line_from_the_right && has_vertical_line_from_the_left
        #in case we eventually tolerate not-quite-vertical lines, this computers the distance in Y directly, rather than depending on the vertical lines' lengths.
        height = [left_vertical_line.bottom - left_vertical_line.top, right_vertical_line.bottom - right_vertical_line.top].max

        top = [left_vertical_line.top, right_vertical_line.top].min
        width = horizontal_line.right - horizontal_line.left
        left = horizontal_line.left
        r = java.awt.geom.Rectangle2D::Float.new( left, top, width, height ) #x, y, w, h
        #rectangles.put(hashRectangle(r), r); #TODO: I dont' think I need this now that I'm in Rubyland
        rectangles << r
      end
    end

    #find rectangles with one vertical line and two horizontal lines that end within $threshold to the ends of the vertical line.
    verticals.each do |vertical_line|
      vertical_line_length = vertical_line.length

      has_horizontal_line_from_the_top = false
      top_horizontal_line = nil
      #for the top horizontal line.
      horizontals.each do |horizontal_line|
        horizontal_line_length = horizontal_line.length
        longer_line_length = [horizontal_line_length, vertical_line_length].max
        corner_proximity = corner_proximity_threshold * longer_line_length

        if euclidean_distance(vertical_line.left, vertical_line.top, horizontal_line.left, horizontal_line.top) < corner_proximity ||
            euclidean_distance(vertical_line.left, vertical_line.top, horizontal_line.right, horizontal_line.top) < corner_proximity
            if top_horizontal_line.nil? || top_horizontal_line.top > horizontal_line.top #is this line is more to the top than the one we've got already.
              has_horizontal_line_from_the_top = true;
              top_horizontal_line = horizontal_line;
            end
        end
      end
      has_horizontal_line_from_the_bottom = false;
      bottom_horizontal_line = nil
      #for the bottom horizontal line.
      horizontals.each do |horizontal_line|
        horizontal_line_length = horizontal_line.length
        longer_line_length = [horizontal_line_length, vertical_line_length].max
        corner_proximity = corner_proximity_threshold * longer_line_length

        if euclidean_distance(vertical_line.left, vertical_line.bottom, horizontal_line.left, horizontal_line.top) < corner_proximity ||
          euclidean_distance(vertical_line.left, vertical_line.bottom, horizontal_line.left, horizontal_line.top) < corner_proximity
          if bottom_horizontal_line.nil? || bottom_horizontal_line.bottom > horizontal_line.bottom  #is this line is more to the bottom than the one we've got already.
            has_horizontal_line_from_the_bottom = true;
            bottom_horizontal_line = horizontal_line;
          end
        end
      end

      if has_horizontal_line_from_the_bottom && has_horizontal_line_from_the_top
        x = [top_horizontal_line.left, bottom_horizontal_line.left].min
        y = vertical_line.top
        width = [top_horizontal_line.right - top_horizontal_line.left, bottom_horizontal_line.right - bottom_horizontal_line.right].max
        height = vertical_line.bottom - vertical_line.top
        r = java.awt.geom.Rectangle2D::Float.new( x, y, width, height ) #x, y, w, h
        #rectangles.put(hashRectangle(r), r);
        rectangles << r
      end
    end
  end
  return rectangles.uniq &:similarity_hash
end

.is_upward_oriented(line, y_value) ⇒ Object 



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# File 'lib/tabula/table_guesser.rb', line 69

def TableGuesser.is_upward_oriented(line, y_value)
  #return true if this line is oriented upwards, i.e. if the majority of it's length is above y_value.
  return (y_value - line.top > line.bottom - y_value);
end