Sun Microsystems, Inc.

Oracle America, Inc.

James A Graham

Jerald R Evans

Thanh Nguyen

Jeannette Hung

Richard Berlin

Jeet Kaul

One particular implementation conforming to aspects of the present invention takes the form of a method for tracking the stability of a data set for multiple observers. More particularly, a tracker object may be used to both mark a particular state of the data and to query if the data remains unchanged. Code that accesses the data set to calculate a result may fetch a reference to a current tracker object associated with the data set. The code may compare the current tracker object received from the data set against the tracker object associated with the last cached result. In an alternate arrangement, a state may be associated with the data set to indicate some characteristics of the data set. The state value associated with the data set may further simplify the action required by a code accessing the data set to receive an accurate calculation.

Method and apparatus for state tracking of data from multiple observers

A method of performing a blending operation between a first pixel having a first pixel alpha value and a first pixel color data value and a second pixel having a second pixel alpha value and a second pixel color data value using a pre-defined set of logical operations and an associated set of pre-computed constant that includes calculating a first pixel blending factor and a second pixel blending factor based upon a selected Porter-Duff compositing equation, the first pixel alpha value, and the second pixel alpha value, such that there are no decisions to be made in an innermost calculation loop.

Method and apparatus to calculate any porter-duff compositing equation using pre-defined logical operations and pre-computed constants

Methods and apparatus for facilitating the sharing of graphics rendering operation implementations between different pixel formats. A lookup table is generated that stores the descriptions of the various rendering operation implementations. A plurality of chains of inherited object descriptors allows traversal from specific to more general descriptions of pixel formats and composition operations. Using these chains, the lookup table can be searched for a rendering operation implementation that best matches the specified criteria.

Methods and apparatus for facilitating the sharing of computer graphics operations

One or more embodiments provide the ability to use multiple path formats in an object oriented system. A path maintains the ability to translate itself into a recognizable format for use by applications. The recognizable format may be a standard Bezier Path format or an iterator that provides the ability to iterate along the path, one curve segment at a time. Multiple applications may use the self-translation ability. In one embodiment, when an application desires to perform a transform, it determines if the transform may be performed on the path (i.e., whether the path is recognizable). If the path is recognizable, the transform is performed directly on the path. If the path is not recognizable, the path translates itself into a recognizable format and the transform performs the action on the recognizable path (the transform must maintain the ability to perform the transform on the standard format). Determining whether the path is recognizable may consist of a two stage negotiation process. During the first stage the path determines if it recognizes the transform. If the path does not recognize the transform, the desired operation is passed onto the transform in the second stage where it is determined if the transform recognizes the path. If the path or the transform is recognizable in either stage the action is performed. However, in the second stage, if the path is not recognizable, the transform requests the path to translate itself and performs the operation on the recognizable path returned.

Representing a path as an object with transformation capability

The present invention provides a method and apparatus that permits the introduction of customized compositing techniques into an application by a developer. A Composite interface and a CompositeContext interface are defined. Custom compositing operations can be defined by implementing these interfaces. A Composite object provides a CompositeContext object that holds the state and performs the compositing work. Multiple CompositeContext objects can be created from one Composite object to maintain separate states in a multi-threaded environment. An object implementing the Composite interface can be set as rendering state on a graphics object that provides rendering methods. This allows arbitrary compositing rules to be used by a developer. In one implementation of the Composite and CompositeContext interfaces, an AlphaComposite class is defined. The AlphaComposite class implements common compositing rules, such as defined by Porter and Duff, for combining source and destination pixels to achieve blending and transparency effects with graphics and images.

Method and apparatus for pixel composition

The invention provides a method and apparatus for customizing and substituting strokes provided by a standard API. In a preferred embodiment, a stroke interface that encapsulates stroking algorithms and interfaces for stroke calculation is provided by an API. The stroke interface is provided in the form of a class. The use of the stroke interface permits additional algorithms and interfaces to be provided as new classes. This allows developers to customize stroke characteristics and attributes. In a preferred embodiment, a basic stroke class contains standard stroke characteristics of a logical pen. These characteristics include line width, end cap shape, line join style, and dash attributes.

Method and apparatus for stroke substitution

One embodiment of the invention provide for access and use of information from fonts in multiple formats (including font format specific information) in an object oriented system. A generic private Font Handler abstract class is defined with multiple methods and references to objects and variables to provide for the storage and retrieval of information. Subclasses of the Font Handler class implement the abstract methods and provide for retrieval of this information. Further, each Font Handler subclass and instances thereof implement a specific interface that provides format specific capabilities. Font information is stored in instances of the Font Handler. A Font class is defined that provides application developers the ability to access the information from the Font Handler. When an application developer desires to use a particular font, the developer creates an instance of the Font class and establishes an association with a corresponding Font Handler instance. Frequently used information may be cached into variables or objects of the Font class. Information that is not cached is retrieved by calling the appropriate Font Handler method through its association. In this manner, one object may be used to access and use fonts of varying formats. An application developer may retrieve general information and format specific information from one object, a Font class object, without any knowledge of the underlying Font Handler. In another embodiment, the Font Handler class is not utilized and the Font class incorporates the methods and references of the Font Handler class thus providing direct access to font information.

Using and accessing information from fonts in multiple formats

Raw image data is separated from color image data such that image data can be operated on independent of a color model. Alternatively, image data can be associated with a color model and image processing operations can operate on the image data in terms of the color model. No color model is presupposed for a given image. When an image processing operation uses a color system, a color system can be selected in which the operation is performed and the source image will be converted. Different color systems can be associated with the same image data to process the image. Where it is not necessary to perform an image processing operation in a color system, the operation can access the image data independent of a color system. In an embodiment of the invention, a Tile object class is comprised of an array of Channel objects. A Channel object is associated with one or more storage bands of image data. A ColorModel object class identifies a color system and specifies a mapping between the raw image data and the color and alpha components of a color system. A BufferedImage object class is defined that associates a ColorModel with a Tile. BufferedImageOp and TileOp interfaces are defined in embodiments of the invention that are implemented by image processing or filtering object classes. A BufferedImageOp interface is used for filtering operations performed within a color system. Filtering operations that are performed outside a color system use the TileOp interface.

Method and apparatus for separating image data from a color system in image processing

A method and apparatus for handling alpha premultiplication is described. In an embodiment, image data is contained within an instance of an image object that also contains a state variable indicating whether the image data is currently premultiplied or non-premultiplied. A method within the image object responds to requests to coerce the image data into a desired or destination premultiplication state. Based on the value of the state variable, the method multiplies or divides the image data components by the alpha component, or does nothing. The state variable is updated to reflect any change in the premultiplication state of the image data. In one embodiment, the image object is implemented as a buffered image object instance containing a tile object instance and a color model object instance. The tile object instance maintains a reference to a data array(s) containing the image data file, and provides methods for inserting and extracting pixel data from the data array(s). The color model object instance contains the premultiplication state variable for the image data, and a method for coercing the image data into a desired premultiplication state. Applications can insure that image data is in the desired premultiplication state by accessing the associated buffered image object instance to invoke the coercion method, and specifying the desired state. The buffered image object instance responds by invoking the data coercion method in the color model object instance, and specifying the desired premultiplication state and the tile object instance containing the image data.

Method and apparatus for handling alpha premultiplication of image data

In a computer graphics windowing system including a color map, a method for managing palette color value contents of the color map. Input color values are received. Error values between each input color value and each palette color value are used to determine a closest palette color value to each input color value. A list of input color values having largest error value distances to their respective closest palette color values is determined. A subset of this list is added to the color map to derive a modified color map. A color value metric process for determining an error value between each input color value and each palette color value comprises converting each input color value and each palette color value to a uniform color space. A lightness weighting constant is used to skew the error value in to be more strongly influenced by differences in lightness than by differences in chromaticity. A look up table having address spaces indexed by RGB index color values is generated. Each address space of the look up table is filled with a color map address of the closest palette color value to the respective RGB index color value referencing the address space.

Growing community of inventors

San Francisco, CA, United States of America

James A Graham