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Emulation of a Data Processor Display Terminal by a Word Processing System - Updating of Line Attribute on the Display Screen

IP.com Disclosure Number: IPCOM000042074D
Original Publication Date: 1984-Mar-01
Included in the Prior Art Database: 2005-Feb-03
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Fountain, JW: AUTHOR [+2]

Abstract

The article on page 5593 covers an expedient for determining only the lines of a particular display that require updating to thus avoid updating of the entire screen in a display. The present article covers a line attribute expedient in the form of a lookup table which permits the most efficient determination of the initial attribute of the data to be updated on the screen. For each updated line, it is necessary to determine the initial attribute. A line attribute table with one entry for each line is used to keep track of these attributes. An algorithm is provided for determining the particular attribute involved in updating each line. The screen-updating algorithm updates one line at a time. For example, to update line n, the initial attribute is obtained from entry n-l on the line attribute table.

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Emulation of a Data Processor Display Terminal by a Word Processing System - Updating of Line Attribute on the Display Screen

The article on page 5593 covers an expedient for determining only the lines of a particular display that require updating to thus avoid updating of the entire screen in a display. The present article covers a line attribute expedient in the form of a lookup table which permits the most efficient determination of the initial attribute of the data to be updated on the screen. For each updated line, it is necessary to determine the initial attribute. A line attribute table with one entry for each line is used to keep track of these attributes. An algorithm is provided for determining the particular attribute involved in updating each line. The screen-updating algorithm updates one line at a time. For example, to update line n, the initial attribute is obtained from entry n-l on the line attribute table. When processing for the nth line is completed, the attribute in effect at the end of the line is placed in the nth entry of the table. In this manner, no backwards search for attributes is required. A uniform performance in screen update is achieved since the speed of the line update is independent of the location of the line on the screen or the complexity of a particular screen format.

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