23. The storage device of claim 22 , wherein the instructions cause the machine to perform operations comprising identifying at least one boundary to which ones of the bounding rectangles are extendable without changing layout relationships among logical blocks in the electronic document.
22. A storage device storing instructions that, when executed, cause a machine to perform operations comprising: receiving logical blocks extracted from the electronic document including a text block comprising text lines each encompassed by a respective bounding rectangle; extending edges of ones of the bounding rectangles to at least one boundary without changing layout relationships among the logical blocks in the electronic document; generating a text layout boundary from extended and unextended edges of the bounding rectangles; and storing a description of the text layout boundary in a machine-readable medium.