Efficient implementation of raster operations flow

• US 7,345,782 B2
• Filed: 05/13/2002
• Issued: 03/18/2008
• Est. Priority Date: 05/13/2002
• Status: Active Grant

• Current Assignee: Texas Instruments, Inc.
• Original Assignee: Texas Instruments, Inc.
• Inventors: Kumar, Santhosh Trichur Natarajan
• Primary Examiner(s): Lee; Thomas D.
• Assistant Examiner(s): BRINICH, STEPHEN M
• Application Number:
  US10/142,868
• Publication Number:
  US 20030210410A1
• Time in Patent Office: 2,136 Days
• Field of Search: 358/1.9, 358/2.1, 358/450, 358 115- 118, 345/592, 345/589, 382/180
• US Class Current: 358/1.16
• 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 15/1806 Receiving job control commands
• CPC Class Codes: G06K 15/1822 Analysing the received data before processing

Abstract

According to one aspect, a printer supports transparency operations by generating mask data at interpretation stage which indicates whether each bit of a page content would be determined by the result of a raster operation or a prior destination value. The mask data can be used to complete quickly rendering of a page image once the rendering starts. Another aspect enables color fills of objects to be performed efficiently. A raster operations engine may determine whether all the points (pixels) of the object would have the same value if the raster operation is performed. If all pixels would have the same value, the value for only one pixel is computed and used for multiple pixels of the object. According to another aspect, when a pattern is to be tiled on an entire image portion, the pattern data is stored in a memory and provided as an input to rendering operation multiple times.

Claims

1. A method of supporting transparency in a printer, said method comprising:

receiving a plurality of commands corresponding to a page to be printed in a page description language, said plurality of commands specifying a plurality of raster operations, wherein said plurality of raster operations use one or more of a source, a paint and a destination as operands to generate a bit map representing an image portion and store said bit map at a destination, said plurality of commands further specifying whether transparency is effective for said source if said raster operation includes a source and said paint if said raster operation includes a paint, said image portion containing a plurality of points;

interpreting said plurality of commands in said page description language into a corresponding display list describing objects to be printed, said interpreting including for each of said plurality of raster operations generating a data mask having a bit for each point of said image portion of said corresponding raster operation, said bit having a first digital value indicating said corresponding point of said image portion should equal said destination or a second digital value indicating said corresponding point of said image portion should equal a result of said raster operation; and

rendering said display list into a bit map for the page, said rendering including generating said bit map based on a result of said plurality of raster operations or said destination according to said corresponding data mask.

2. The method of claim 1, wherein:

said step of rendering said display list includes not performing one of said plurality of raster operations for a point of said image portion if said bit in said data mask indicates that the corresponding point of said image portion should equal said destination.

3. The method of claim 1, wherein:

said step of rendering said display list includes

performing said plurality of raster operations to generate a corresponding plurality of results for each point of said image portion; and

selecting for each point of said image portion of a raster operation either said corresponding result or a corresponding value in said destination according to said corresponding bit in said data mask.

4. A printer supporting transparency, said printer comprising:

means for receiving a plurality of commands corresponding to a page to be printed in a page description language, said plurality of commands specifying a plurality of raster operations, wherein said plurality of raster operations use one or more of a source, a paint and a destination as operands to generate a bit map representing an image portion and store said bit map at a destination, said plurality of commands further specifying whether transparency is effective for said source if said raster operation includes a source and said paint if said raster operation includes a paint, said image portion containing a plurality of points;

means for interpreting said plurality of commands in said page description language into a corresponding display list describing objects to be printed, said interpreting including for each of said plurality of raster operations generating a data mask having a bit for each point of said image portion of said corresponding raster operation, said bit having a first digital value indicating said corresponding point of said image portion should equal said destination or a second digital value indicating said corresponding point of said image portion should equal a result of said raster operation; and

means for rendering said display list into a bit map for the page, said rendering including generating said bit map based on a result of said plurality of raster operations or said destination according to said corresponding data mask.

5. The printer of claim 4, wherein:

said means for rendering said display list includes means for not performing one of said plurality of raster operations for a point of said image portion if said bit in said data mask indicates that the corresponding point of said image portion should equal said destination.

6. The printer of claim 4, wherein:

said means for rendering said display list includes

means for performing said plurality of raster operations to generate a corresponding plurality of results for each point of said image portion; and

means for selecting for each point of said image portion of a raster operation either said corresponding result or a corresponding value in said destination according to said corresponding bit in said data mask.

7. A computer readable medium having encoded therein one or more sequences of computer instructions for causing a printer to support transparency, wherein execution of said one or more sequences of computer instructions by one or more processors contained in said printer causes said one or more processors to perform the actions of:

receiving a plurality of commands corresponding to a page to be printed in a page description language, said plurality of commands specifying a plurality of raster operations, wherein said plurality of raster operations use one or more of a source, a paint and a destination as operands to generate a bit map representing an image portion and store said bit map at a destination, said plurality of commands further specifying whether transparency is effective for said source if said raster operation includes a source and said paint if said raster operation includes a paint, said image portion containing a plurality of points;

interpreting said plurality of commands in said page description language into a corresponding display list describing objects to be printed, said interpreting including for each of said plurality of raster operations generating a data mask having a bit for each point of said image portion of said corresponding raster operation, said bit having a first digital value indicating said corresponding point of said image portion should equal said destination or a second digital value indicating said corresponding point of said image portion should equal a result of said raster operation; and

rendering said display list into a bit map for the page, said rendering including generating said bit map based on a result of said plurality of raster operations or said destination according to said corresponding data mask.

8. The computer readable medium claim 7, wherein:

said step of rendering said display list includes not performing one of said plurality of raster operations for a point of said image portion if said bit in said data mask indicates that the corresponding point of said image portion should equal said destination.

9. The computer readable medium claim 7, wherein:

said step of rendering said display list includes

performing said plurality of raster operations to generate a corresponding plurality of results for each point of said image portion; and

selecting for each point of said image portion of a raster operation either said corresponding result or a corresponding value in said destination according to said corresponding bit in said data mask.