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. The uncompressed output data is supplied to an output display device for display.
CROSS REFERENCE TO RELATED APPLICATIONS
This application is a continuation-in-part of co-pending parent patent application 07/974,204, filed Nov. 10, 1992 on behalf of Ronald S. Gentile, entitled, "Method and Apparatus for Processing Data for a Visual-Output Device with Reduced Buffer Memory Requirements," assigned to the assignee of this present application, and which is incorporated by reference herein.
A method and system for compressing graphic data by dividing the data into segments is disclosed. The size of the divided segment is programmable. A frame buffer partitioned into a compressed frame buffer and an uncompressed frame buffer stores graphic data. Each segment of the graphic data is compressed by three different algorithms that encode the graphic data as a plurality of code-words. Each code-word for the segment is taken from the algorithm that can compress the largest number of pixels in the code-word. A header is used to indicate the number of code-words and the compression method used in each code-word. The total number of bytes obtained from the compression of a segment is compared to a pre-defined limit to determine if the compression of the segment is successful. The successfully compressed data of a segment are written to the compressed frame buffer. A compression status flag buffer is used to identify if a segment is compressed or not. A decompressor decompresses or passes the graphic data to a pixel stream for display according to the compress status flag.
A method and apparatus for performing compression and/or decompression is described. In one embodiment, the present invention comprises a system having a buffer, a wavelet transform unit, and a coder. The wavelet transform unit has an input coupled to the buffer to perform a wavelet transform on pixels stored therein and to generate coefficients at an output. The coder is coupled to the wavelet transform unit to code the transformed pixels received from the buffer.
A computer controlled sheet-fed offset printing machine is described which includes an Interpreter-program for obtaining an image of the signal-state of specified interfaces of the many interfaces that are needed for the operation of the computerized printing press. The Interpreter-program has access to a reserved region of memory for storing and manipulating, if desired, the image of the signal-state. Furthermore, the Interpreter-program has very limited and defined access to the inputs and resources used by the control programs used to operate the computerized printing press. This ensures that the control programs can execute in real-time unaffected by the execution of the Interpreter-program while data is acquired by the Interpreter-program while the computerized printing press is in operation. The Interpreter-program can execute diagnostic routines and provide data for detecting and correcting errors that are otherwise hard to localize in a complex system with complex software.
A source image (101) consisting of more than one type of image is efficiently compressed. The source image (101) is divided into regions, and each region is assigned to one image type. Separate images (105) based on each image type are constructed from those regions belonging to that image type. These separate images (105) are compressed using schemes optimized for the image type. Later these compressed images are decompressed and reassembled into a reproduction (108) of the original source image (101).
Sets of pixel data defining parts of rasterized portions of an image are received. At least one of the parts of one of the rasterized portions of the image overlaps another part of that portion of the image. The pixel data that defines the overlapping part includes mask data that identifies pixels of the overlapping part that are to be included in the image. The sets of pixel data are decompressed. The decompressed data are used to generate a series of the rasterized portions of the image including the pixels identified in the mask data. While each of the rasterized portions of the image is being used by a print engine, another of the rasterized portions of the series is being generated.
