The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Feb. 15, 2000
Filed:
Jun. 30, 1997
Jeannette Hung, Redwood City, CA (US);
Jerald R Evans, Mountain View, CA (US);
James Graham, Sunnyvale, CA (US);
Sun Microsystems, Inc., Palo Alto, CA (US);
Abstract
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.