Vector to raster processor

• US 4,254,467 A
• Filed: 06/04/1979
• Issued: 03/03/1981
• Est. Priority Date: 06/04/1979
• Status: Expired due to Term

• Current Assignee: Xerox Corporation (Xerox Holdings Corp.)
• Original Assignee: Xerox Corporation (Xerox Holdings Corp.)
• Inventors: Davis, Jack R., Gold, Philip S.
• Primary Examiner(s): Smith, Jerry
• Application Number:
  US06/045,374
• Time in Patent Office: 638 Days
• Field of Search: 364/515, 364/520, 364/521, 364/719, 340/720, 340/730, 340/739
• US Class Current: 345/443
• CPC Class Codes: G06K 15/00 Arrangements for producing a permanent visual presentation of the output data , e.g. computer output printersprinting or plotting combined with another operation, e.g. with conveying, G06K17/00
• CPC Class Codes: G06K 15/128 generating or processing printable items, e.g. characters
• CPC Class Codes: G06K 15/1848 Generation of the printable image
• CPC Class Codes: G06K 15/1857 involving parallel processing in the same printing apparatus
• CPC Class Codes: G06K 15/22 using plotters
• CPC Class Codes: G06K 2215/0042 Rasterisation
• CPC Class Codes: G06K 2215/0065 Page or partial page composition
• CPC Class Codes: G09G 5/42 characterised by the display of patterns using a display memory without fixed position correspondence between the display memory contents and the display position on the screen

Abstract

In raster data plotting of graphic information, vector data comprising the plot is generated by the host computer via the user'"'"'s application program. For maximum plotter efficiency and relief of host system time, vector to raster conversion is carried out by an offloading processor which receives vector data ordered in vector bands constituting the plot. Vector data in each band is received in random order and is initialized for vector computational values. The computational values for each vector are stored in parallel format in a vector memory in the initialized random order for subsequent retrieval in parallel format for vector to raster processing of each scan line of the band and then restored in parallel format in the vector memory if the vector is still active. A vector type, designating vector orientation relative to Cartesian coordinates, is one of the computational values for each vector. The time required for vector to raster conversion is further enhanced by processing each vector directly according to its vector type found in the microcode of the processor.

Claims

1. In a vector to raster processor for converting vector coordinate information forming a plot into a raster scan line format for presentation to a plotter having a multi-electrode nib array constituting a scan line and addressable between incremental movements of a record medium in a direction transverse to said array comprising

(a) means for receiving coordinate information of vectors within a current vector band, constituting a predetermined number of scan lines being one of a plurality of bands of equal but of predetermined length making up said plot, the length of said bands being largely dependent on the vector density of said plot, said vector coordinate information being received in random order within each band,

(b) means for initializing said vector coordinate information to provide vector computational values for each vector,

(c) means for storing said initialized vector values for each vector in parallel format in their received random order,

(d) parallel processing means for accessing said storage means and comprising a plurality of parallel operated processor components, said parallel processing means simultaneously dequeuing in parallel format said initialized vector values, simultaneously processing said initialized vector values via one of said processor components and simultaneously requeuing in parallel format the initialized vector values in their previous stored random order into said storage means if the vector requires subsequent processing.

2. In the vector to raster processor of claim 1 wherein said initialized vector values for each vector include the incremental distance in the major axis direction, the incremental distance in the minor axis direction, slope approximation of the major incremental change relative to the minor incremental change, the number of nibs to be set for a given vector length, and the location of the address of the nib to be set for a given scan line in the current band.

3. In the vector to raster processor of claim 2 wherein there is raster buffer means to store the set nibs and means to output said raster buffer means when the nibs have been set for a given scan line in the current vector band.

4. In the vector to raster processor of claim 1 wherein said storage means also includes a section for inputting initialized vector coordinate information for the next vector band, the amount of storage in said next vector band section governed by the amount of storage available in storing and processing the initialized vector values for the vectors in the current vector band.

5. In the vector to raster processor of claim 1 wherein one of said initialized values comprises the vector type indicative of predetermined vector orientation relative to known Cartesian coordinates.

6. In the vector to raster processor of claim 5 wherein said parallel processing means includes means to process each vector for rasterization according to its vector type.

7. In a vector to raster processor for converting vector coordinate information into a raster scan line format for presentation to a terminal device, said coordinate information comprising a plurality of vectors constituting an original plot, each vector having a set of computed vector values, said processor characterized by

parallel processing means which includes a plurality of parallel computational component means,

vector memory means coupled to said computational component means to store in parallel format said vector value sets,

said vector value sets received in random order in said vector memory means and not reordered therein to one or more of their computed vector values, and

said vector value sets being retrieved in parallel format from said vector memory means and processed in parallel by said computational component means in their randomly received and stored order with final ordering of vectors falling in any given raster scan line being accomplished by queuing all of the stored vector value sets and requeing them into said vector memory means if the vector extends into the next raster scan line.

8. In the vector to raster processor of claim 7 wherein said vectors are received in vector bands, the total of said bands comprising the original plot, each band constituting a predetermined number of raster scan lines, said number based upon the density of vectors in the original plot.

9. In the vector to raster processor of claim 8 wherein said vector memory means comprises a section for vector value sets for a current vector band and a section for some or all of the vector value sets in the next vector band, the amount of storage in said next vector band section governed by the amount of storage available in storing and processing vector value sets for vectors in the current vector band.

10. In the vector to raster processor of claim 7 wherein one of said computational component means designates vector type as one of said computed vector values for each of said vectors and code subroutine means in said parallel processing means for processing the vector value sets in accordance with the designated vector type.

11. In the vector to raster processor of claim 7 wherein said vectors are received in bands of vector, said bands comprising said plot in its entirety.