Abstract: A method for estimating a white point includes displaying a plurality of grey patches on a screen; requesting that a user select a patch corresponding to a neutral grey; and iteratively converging to a patch where the estimated white point is the most neutral grey point.

Abstract: A system for processing data objects each representing display data for a display area and each having a data type and a location in the display area including a divider for dividing the display area into a plurality of non-overlapping regions containing the data objects where each region has a location and a region type derived from data types of the data objects in the region. A plurality of compression mechanisms and decompression mechanisms are provided where each compression mechanism has an associated decompression mechanism. A compressor selects one of the compression mechanisms for each of the regions according to its region type and then uses the selected compression mechanism to compress those portions of the data objects found in the region, thereby producing compressed object data. A memory is coupled to the compressor for storing compressed object data.

Abstract: A method and apparatus for reducing storage requirements for display data on a computer system. Data objects to be displayed are organized into display lists and each data object includes an object type, such as text, graphic, and image. The data objects are rasterized into an uncompressed band buffer and divided into non-intersecting bitmap regions each identified with one or more object types. Each non-empty region is assigned a compression algorithm dependent upon the type of the region and specified compression constraints. The regions are combined with each other into larger regions if appropriate, and each region is compressed using its assigned compression algorithm into a compressed band buffer, thus reducing the required storage space for the data objects. The compressed data is decompressed in scan line order with a selected decompression algorithm corresponding to the assigned compression algorithms to produce uncompressed output data.

Abstract: A two-dimensional page representation to be printed has a combination of text, graphic and image representation types. A data memory stores data representative of the page representation. A program memory stores program instructions including a plurality of different algorithms for compressing data associated with corresponding different representation types and their combinations.

Abstract: A two-dimensional page representation to be printed has a combination of text, graphic and image representation types. A data memory stores data representative of the page representation. A program memory stores program instructions including a plurality of different algorithms for compressing data associated with corresponding different representation types and their combinations.

Abstract: A two-dimensional page representation to be printed has a combination of text, graphic and image representation types. A data memory stores data representative of the page representation. A program memory stores program instructions including a plurality of different algorithms for compressing data associated with corresponding different representation types and their combinations.

Abstract: A two-dimensional page representation to be printed has a combination of text, graphic and image representation types. A data memory stores data representative of the page representation. A program memory stores program instructions including a plurality of different algorithms for compressing data associated with corresponding different representation types and their combinations.