Sun Microsystems, Inc.

Jeannette Hung

James A Graham

Jerald R Evans

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.

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Redwood City, CA, United States of America

Jeannette Hung