class Prawn::Table

def draw
  with_position do
    # Reference bounds are the non-stretchy bounds used to decide when to
    # flow to a new column / page.
    ref_bounds = @pdf.reference_bounds
    # Determine whether we're at the top of the current bounds (margin box or
    # bounding box). If we're at the top, we couldn't gain any more room by
    # breaking to the next page -- this means, in particular, that if the
    # first row is taller than the margin box, we will only move to the next
    # page if we're below the top. Some floating-point tolerance is added to
    # the calculation.
    #
    # Note that we use the actual bounds, not the reference bounds. This is
    # because even if we are in a stretchy bounding box, flowing to the next
    # page will not buy us any space if we are at the top.
    #
    # initial_row_on_initial_page may return 0 (already at the top OR created
    # a new page) or -1 (enough space)
    started_new_page_at_row = initial_row_on_initial_page
    # The cell y-positions are based on an infinitely long canvas. The offset
    # keeps track of how much we have to add to the original, theoretical
    # y-position to get to the actual position on the current page.
    offset = @pdf.y
    # Duplicate each cell of the header row into @header_row so it can be
    # modified in before_rendering_page callbacks.
    @header_row = header_rows if @header
    # Track cells to be drawn on this page. They will all be drawn when this
    # page is finished.
    cells_this_page = []
    @cells.each do |cell|
      if start_new_page?(cell, offset, ref_bounds) 
        # draw cells on the current page and then start a new one
        # this will also add a header to the new page if a header is set
        # reset array of cells for the new page
        cells_this_page, offset = ink_and_draw_cells_and_start_new_page(cells_this_page, cell)
        # remember the current row for background coloring
        started_new_page_at_row = cell.row
      end
      # Set background color, if any.
      cell = set_background_color(cell, started_new_page_at_row)
      # add the current cell to the cells array for the current page
      cells_this_page << [cell, [cell.relative_x, cell.relative_y(offset)]]
    end
    # Draw the last page of cells
    ink_and_draw_cells(cells_this_page)
    @pdf.move_cursor_to(@cells.last.relative_y(offset) - @cells.last.height)
  end
end