Computer graphics processing and selective visual display system – Computer graphics processing – Graphic manipulation
Reexamination Certificate
1997-12-22
2001-11-06
Luu, Matthew (Department: 2672)
Computer graphics processing and selective visual display system
Computer graphics processing
Graphic manipulation
Reexamination Certificate
active
06313847
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates generally to methods and systems for blending computer generated graphics objects and more particularly to methods and apparatus for blending computer generated graphics objects in a frame buffer.
A computer system can output data to a wide variety of output display devices. Output display devices such as laser printers, plotters, image setters and other printing devices produce an image or “visual representation” onto a sheet of paper, a piece of film or the like, while output display devices such as computer monitors develop visual representations on a computer screen.
Many output display devices receive display data in the form of a “pixelmap” and generate visual representations from the display data. A pixel is a fundamental picture element of a visual representation generated by a display device, and a pixelmap is a data structure including information concerning a number of pixels of the representation.
A printing device prints dots on a piece of paper corresponding to the information in a pixelmap. Alternatively, a computer monitor illuminates pixels based upon the information of the pixelmap. A “raster” output device creates a visual representation by displaying the array of pixels arranged in rows and columns from a pixelmap. Most output devices, other than plotters, are raster output devices.
Printing and visual output devices that produce output in response to page description language input are widely used. A page description language is a high level language for describing objects to be displayed by an output device. The PostScript® language developed by Adobe Systems Incorporated of San Jose, Calif., is an example of a page description language. An image to be displayed may be represented and stored in a page description format as a page description language file which includes one or more objects. Generally, a page description language is device independent.
In operation, a conventional printing device configured to process a page description language file interprets the objects within the file and renders the data into a pixelmap to be painted into a frame buffer. Typically, the frame buffer is large enough to store (at least in compressed form) any page that might be printed, and rendered pixelmaps are stored in this buffer. When the entire page has been painted, data stored in the frame buffer may transferred to a print engine or marking engine for printing.
Transparency is a visual blending effect obtained when a background object (image, text, lines or filled regions) is partially obscured by a foreground object that is drawn over the background object. Numerous other blending effects may be used to integrate foreground and background graphics data. Examples of blending effects include a drop shadow effect, a screen effect, darker and lighter effects and overprinting effects.
The manipulation of graphics data at a printer or output display to achieve blending effects typically requires a large amount of memory. Some printing devices include limited memory or shallow frame buffers for performance reasons and thus hereto before were incapable of processing a blending operation at the printer.
SUMMARY
In general, in one aspect, the invention features a method blending graphics data received by a printing device. The method includes rendering a first object received into a frame buffer; receiving a second object including blending instructions for blending the second object and the first object; and retrieving rendered data associated with the first object from the frame buffer and rendering a blend of the first and second object into the frame buffer according to a user-selectable blending algorithm.
Preferred embodiments of the invention include one or more of the following features. The frame buffer is a deep frame buffer. The method includes reducing a bit depth of data stored in the frame buffer and printing reduced bit depth blended data. The reducing step includes halftoning the blended data. The reducing step includes dithering the blended data. The reducing step includes error diffusing the blended data. The blending algorithm is selected from the group of transparency, shadow, overprinting, darkening, lightening, screen effect and additive effect. The blending instructions include a blend operator defining a blend algorithm for blending two objects.
In general, in another aspect, the invention features a method blending graphics data received by a printing device to provide a blending effect for a foreground object with respect to a background object. The method includes receiving a background object; rendering the background object to derive background rendered data; storing the background rendered data in a frame buffer; receiving a foreground object to be blended with the background object; rendering the foreground object to derive foreground rendered data; retrieving the background rendered data from the frame buffer and blending the foreground and background rendered data to generate a blend; and printing the blend.
In general, in another aspect, the invention features a method blending graphics data received by a printing device. The method includes rendering a first object received into a frame buffer; receiving a second object including blending instructions for blending the second object and the first object; retrieving rendered data associated with the first object from the frame buffer; rendering a blend of the rendered data associated with the first object and second object according to a user-selectable blending algorithm to generate blend data; storing blend data in the frame buffer; and reducing the bit depth of the blend data prior to printing.
In general, in another aspect, the invention features apparatus for blending graphics data in a printing device. The apparatus includes an interpreter for receiving object data associated with a background and a foreground of an image to be printed; a render engine for rendering object data; a frame buffer for storing rendered data; and a blend processor for retrieving rendered data stored in the frame buffer and for blending retrieved rendered data associated with a background object with rendered data associated with a foreground object prior to printing.
Preferred embodiments of the invention include one or more of the following features. The render engine generates pixel data from higher level object data, receives object data from the interpreter and paints pixel data representative of the object data into the frame buffer and the blend processor. The interpreter receives a blend operator including blend instructions for blending a received object with an object that has been previously rendered. The apparatus also includes a reduction engine for reducing a bit depth of data stored in the first buffer prior to printing. The reduction engine halftones the data. The reduction engine dithers the data. The reduction engine error diffuses the data.
In general, in another aspect, the invention features a printer configured to receive a page description language description of a page to be printed. The printer includes a frame buffer for storing rendered data; a blending engine for extracting previously rendered data from the frame buffer and blending the previously rendered data with newly received object data; and a print engine for printing blended data resulting in a blending of graphics data according to a user defined blending function.
Preferred embodiments of the invention include one or more of the following features. The newly received object data is rendered prior to blending with the previously rendered data.
Among the advantages of the invention are one or more of the following.
The use of the inventive methods is transparent for non-blended graphics data and thus a performance penalty only occurs when processing blended graphics objects.
A blending process is provided in a printing device to allow for the blending of new data objects with previously rendered data stored in a frame buffer in accordance with user defined blendi
Adobe Systems Incorporated
Fish & Richardson P.C.
Harrison Chante′
Luu Matthew
LandOfFree
Blending graphics objects in a frame buffer does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Blending graphics objects in a frame buffer, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Blending graphics objects in a frame buffer will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2602612