Method of providing raster information for a graphics display employing linked lists

• US 4,660,029 A
• Filed: 07/06/1984
• Issued: 04/21/1987
• Est. Priority Date: 07/06/1984
• Status: Expired due to Term

• Current Assignee: Xerox Corporation (Xerox Holdings Corp.)
• Original Assignee: Tektronix Incorporated (Fortive Corp.)
• Inventors: Houda, Pavel, Springer, Richard A., Belshee, Rodney B.
• Primary Examiner(s): Brigance, Gerald L.
• Assistant Examiner(s): Brier, Jeffery A.
• Application Number:
  US06/628,182
• Time in Patent Office: 1,019 Days
• Field of Search: 340/726, 340/744, 340/747, 340/750, 340/798, 340/799, 364/518, 364/521
• US Class Current: 345/553
• CPC Class Codes: G06K 15/10 by matrix printers G06K15/028 takes precedence
• CPC Class Codes: G06K 2215/0065 Page or partial page composition

Abstract

Graphics commands for a display are listed and divided into sublists corresponding to separate strips or bands of the display, and these sublists drive the display memory consecutively and substantially concurrently with the processing of additional sublists. Graphics commands relating to graphics extending between bands are transferred to successive sublists during processing to provide their display in successive bands. A pair of band size bit map memories are alternately loaded with band information and read out.

Claims

1. The method of providing information for a graphics display in response to identification, in the form of high level graphics commands, of graphics to be portrayed, comprising the steps of:

receiving commands for said graphics,

dividing said commands into lists related to regions of the display,

transforming the commands sequentially by lists into information for writing to respective regions of said display,

and transferring commands from one list to a crossing list as they relate to graphics extending beyond a currently written region of said display into another region whereby to continue the writing of a transferred command in the last mentioned region, including employing said crossing list in writing the last mentioned region.

2. The method according to claim 1 wherein said information for writing to said display is written sequentially and alternately to plural memory regions from which raster information is sequentially and alternately provided to said display.

3. The method of providing information for a graphics display, in response to identification, in the form of high level graphics commands, of graphics to be portrayed, comprising the steps of:

receiving the commands for said graphics,

dividing said commands into lists corresponding to regions of said display in which they are to be portrayed,

and forming said display sequentially by regions in response to separate lists of graphics identification,

including forming said display with linking commands for graphics extending between regions whereby a last mentioned command can be used sequentially first for display in one region and then in another region according to the extension of said graphics.

4. The method of providing raster information for a graphics display, in response to digital indentification of one or more graphics to be portrayed, comprising the steps of:

forming a plurality of successive images each corresponding to a band of said display,

receiving the identification of said graphics and dividing said identification of said graphics into sublists, each corresponding to a band of said display within which one or more graphics to be portrayed,

entering each of said graphics in the form of pixel indentifying data into memory for display insofar as the graphics are contained in a sublist for a given band,

repeating the last step for a subsequent band,

forming a linking list for graphics extending into a band subsequent to the given band,

and merging said linking list with a further sublist of graphics corresponding to the subsequent band for entry into said memory substantially concurrently with pixel identifying data for graphics in the sublist for the subsequent band.

5. The method according to claim 4 wherein said forming of a plurality of successive images occurs substantially concurrently with forming of linking lists and merging linking lists with further sublists for entry into memory.

6. The method of providing information for a graphics display, in response to commands identifying graphics to be portrayed, comprising the steps of:

receiving the commands for said graphics,

forming said graphics commands into a display list,

dividing said display list into sublists corresponding to separate bands of said display, according to the portion of the display where graphics are to be initially portrayed,

entering the graphics from a sublist for a first band into a first portion of bit map memory,

forming a linking list for graphics, the portrayal of which would extend from said first band of said display into a second and adjacent band,

merging said linking list with the sublist for said second band,

and entering the merged graphics from said linking list and the sublist for the second band into a second portion of bit map memory,

wherein the first and second portions of bit map memory are alternately read out for providing said display.

7. The method according to claim 6 wherein said graphics for said second band are entered into said second portion of bit map memory while said first portion of bit map memory is read out for display.

8. The method of providing information for a graphics display, in response to high level computer commands for graphics to be portrayed, comprising the steps of:

receiving the commands for said graphics,

forming said commands into a display list,

dividing said display list into sublists corresponding to separate bands of said display according to the portion of the display where graphics are to be displayed,

transforming commands from a sublist for a first band into pixel information for entry into a first portion of bit map memory,

maintaining a crossing list for commands as would identify graphics extending beyond said first band,

and transforming commands from said crossing list and from a subsequent sublist into pixel information for entry into a second portion of bit map memory,

wherein the first and second portions of bit map memory are alternately read out for providing said display.

9. The method according to claim 8 wherein pixel information for a subsequent band is entered into said second portion of memory while a first portion of memory is read out for display.