Method and apparatus for formatting a line of text containing a complex character prior to text justification

摘要

A word or text processing system has a bidirectional printer with formatting capability. A line of text is printed in one direction, and the printer is backspaced to form complex characters by adding overstrikes, such as underlining or accent marks. The formatting unit includes a storage mechanism for storing encoded space images, including variable width spaces, in a first scan pass. Space images overlapped by a backspace are deleted from the storage mechanism during the scan pass, and the number of spaces backspaced over is subtracted from the total count of expandable spaces available for justification. Upon detecting a space in the input data during the format pass, the system examines the space storage mechanism to determine if the image of the space is encoded therein. A space is expanded for line justification only if the space is encoded in the space storage mechanism.