1. A pen-based computer method for a user interactively to edit a series of glyphs which include one or more of handwritten script, text or bitmapped images using a pen-type input device on a document display having a series of lines defining machine editable line spaces for writing script, the method comprising: inputting and displaying a bit-mapped image containing a series of glyphs arranged in a generally linear format but initially unconstrained to the line spaces; decomposing the image into image lines; and mapping each glyph in the image lines to one of the machine editable line spaces; the step of decomposing the image including: establishing a baseline for a current image line; determining a height of the current image line; and determining beginning and end points of the current image line relative to the image; the step of mapping including defining the machine editable line space according to the baseline, height, and beginning and end points, and the step of establishing a baseline comprising: detecting all non-zero bits in a row which represent visible dots on the image; counting the detected bits; and establishing a baseline on the row where the count is less than or equal to a predetermined number of bits.