US 4,451,825 AGranted

Digital data display system

AssigneeInternational Business Machine Corporation

InventorsStephen T. Hall, Raymond Hardiman, Peter W. Johnson, Peter Quarendon, Harold W. Tuffill

Life of this patent

Estimating the term…

Loading patent…

Abstract

A digital data display system in which the display device includes a plurality of random access stores into which character cell definitions are loaded from a remote central processing unit. A character cell may be a 9.times.16 picture element matrix and each is defined in the CPU according to the requirements of a display request received from a users application program. The system control services include a graphics manager and graphics routines which construct a character buffer and character cell definition table according to the picture to be displayed. A character cell definition that is required more than once in a picture is only included once in the definition table, the character buffer having the required number of pointers to the one definition. When the character buffer and character definition table have been constructed, they are transmitted to the display device using a data communication system. The system can be used for color or monochrome displays.

Claims9

Dependent claims

A digital data display system for presenting a graphical picture on an output device in which the area or screen from which the picture is to be viewed is notionally divided into a plurality of character cells each of which comprises a predetermined number of picture elements (pels), the system comprising

first means for creating, in response to input information, a first level description of all the elements of a picture to be presented,
second means for storing a screen definition table having an entry for each character cell of the display area,
third means for calculating for each element of the picture, the pattern of pels in associated character cells required to display the elements, storing the calculated pattern in a table in a character cell store and associating the respective entry in the screen definition table with the required pattern in the character cell store,
fourth means to determine when a particular character cell pattern has already been calculated as required for a picture and to associate the respective screen definition table entries with only one copy of the particular character cell pattern, and
fifth means for transferring the screen definition table to a screen definition buffer store and the character cell pattern table to a character cell buffer store in the display device,
whereby the contents of the screen definition buffer store and character cell buffer store control the construction of a picture presented by the display device.

3 more elements

A method, implemented in a digital data display system, for presenting a graphical picture on an output device in which the area or screen from which the picture is to be viewed is notionally divided into a plurality of character cells each of which comprises a predetermined number of picture elements (pels), said method comprising the steps of

creating, in response to input information, a first level description of all the elements of a picture to be presented,
storing a screen definition table having an entry for each character cell of the display area,
calculating for each element of the picture, the pattern of pels in associated character cells required to display the elements, storing the calculated pattern in a table in a character cell store and associating the respective entry in the screen definition table with the required pattern in the character cell store,
determining when a particular character pel pattern has already been calculated as required for a picture and associating the respective screen definition table entries with only one copy of the particular character cell pel pattern, and
transferring the screen definition table to a screen definition buffer store and the character cell pattern table to a character cell buffer store in the display device,
whereby the contents of the screen definition buffer store and character cell buffer store control the construction of a picture presented by the display device.

3 more elements

Dependencies are inferred from the claim text.