# File lib/pdf/reader/page_state.rb, line 199
      def ctm_transform(x, y, z = 1)
        [
          (ctm[0,0] * x) + (ctm[1,0] * y) + (ctm[2,0] * z),
          (ctm[0,1] * x) + (ctm[1,1] * y) + (ctm[2,1] * z)
        ]
      end