Abstract

A method of data compression which allows an enlarged font of complex characters to be produced by scaling from data representing a stored font of complex characters is disclosed. The scaling procedure involves the insertion of horizontal and vertical lines into the stored font to effect vertical and horizontal expansion, respectively, of the stored font. These lines are inserted so as to preserve the basic shape of the characters according to the following procedure. First, the dot matrix of each character is partitioned into sections, each containing a very pronounced and recognizable portion of the character. Then a decision is made in which sections to insert lines so that enlargement is attained without distorting the basic overall shape of the character. Next, a decision is made where in the sections the lines are to be inserted. Finally, a decision is made as to what the inserted lines are to look like. The results of these decisions are stored with data representing the stored font as side information so that an enlarged version of the font can be generated on the fly without need of arithmetic processing. A refinement of this basic technique additionally stores a sparse matrix containing the error of the generated matrix as compared with the original one. This additional information permits the generation of the exact duplicate of the original font.