PDF::Writer：PDF::SimpleTable::Column::Heading#title, #title=

require 'pdf/simpletable'

pdf = PDF::Writer.new

PDF::SimpleTable.new do |tab|
  tab.column_order = %w(col1 col2 col3)

  tab.show_lines    = :all
  tab.show_headings = true
  tab.columns["col1"] = PDF::SimpleTable::Column.new("COL1") {|col|
    col.heading = PDF::SimpleTable::Column::Heading.new("Race")
    p col.heading.title
    col.heading.title = "hoge"
    p col.heading.title
  }

  data = [
    { "col1" => "foo", "col2" => "bar", "col3" => "baz" },
  ]

  tab.data.replace data
  tab.render_on(pdf)
end

pdf.save_as("2008032200.pdf")

で、

"Race"
"hoge"