Computer graphics processing and selective visual display system – Display driving control circuitry – Controlling the condition of display elements
Reexamination Certificate
1999-07-29
2004-10-05
Nguyen, Cao (Kevin) (Department: 2173)
Computer graphics processing and selective visual display system
Display driving control circuitry
Controlling the condition of display elements
C345S215000
Reexamination Certificate
active
06801225
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to data storage in OLE systems.
2. Description of the Prior Art
Some computer-based data processing systems make use of a “core” computer program and a number of possible program modules or “plug-ins” which can be loaded when required.
One way in which the various parts of the data processing system can communicate with one another is the so-called “Object Linking and Embedding” (OLE) protocol, described in the book, “Understanding ActiveX and OLE”, David Chappell, Microsoft Press, 1996.
In the OLE system a software designer can implement different sections of a computer program as so-called “COM
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objects”. Each COM object supports one or more COM “interfaces”, each including a number of “methods”. A method is a function or procedure to carry out a specific action. COM methods can be called by software using that COM object. The system is restricted so that other parts of the software (so-called “clients”) using a COM object can do so only via the defined interfaces—so they cannot directly access program code or data within the object other than via the defined COM interfaces.
1
Component Object Model
One example of a data processing system in which this type of structure can be useful is a computer-based video special effects system. In such a system, the user can generally set up a composite special effect to be applied to a video sequence by selecting a succession of effects modules from a large number of available modules. For example, a sequence of effects set up by a user might comprise:
(i) image loader
(ii) motion tracker
(iii) lighting effect linked to motion tracking and image loader
(iv) image realignment linked to motion tracking and image loader
Each of these effects can be implemented as a program module or plug-in (a COM object), with data being routed between the modules under the overall control of a core program (one or more objects capable of presenting COM interface(s) as required to communicate with the plug-ins). So, the interfaces between the core and plug-in programs are defined under the COM system, but beyond that level the plug-in designer is generally free to implement the methods required under those interfaces in any appropriate way.
In a system of this type employing multiple COM objects, it is generally considered undesirable that each object should save its working or results data in a separate data file. Indeed, if this discussion went to a deeper level, it would be clear that such an arrangement would go against much of the reasoning which led to the establishment of the OLE system. Instead, data in this type of system is stored by all of the objects in a single file or “compound document”, but with an ordered structure within that compound document.
Basically, inside the compound document, a structure analogous to a file and directory structure is provided. The equivalent of a directory is a so-called “storage”, and the analogy of a file is a so-called “stream”. Each compound document contains a root storage, below which is a familiar tree structure of storages and streams. The COM stream interface is simpler than the COM storage interface, but of course the storage interface offers more flexibility.
In general, each COM object can be assigned either its own storage or its own stream in which to store its working data. However, in a hierarchical system such as the video special effects processor described above, where a core program coordinates operation of a number of plug-ins, the arrangement used in previous systems is to allocate a stream to each effects plug-in.
SUMMARY OF THE INVENTION
This invention provides data processing apparatus having:
a core object for controlling overall operation of the apparatus; and
a plurality of plug-in COM objects arranged to communicate with the core object;
the core object presenting a COM stream interface and a COM storage interface to the plug-in COM objects for use in storing and/or retrieving working data.
The invention recognizes that simply allocating either a storage or a stream to all plug-ins in a predetermined way places too many constraints on the design and operation of a plug-in object. Instead, a plug-in is allocated both a stream, so that it can—if desired—store its working data in a straightforward manner, and a storage, so that it can—if desired—store its working data under its own “directory” arrangement of streams and storages. This choice can then be left to the plug-in designer.
The above, and other objects, features and advantages of this invention will be apparent from the following detailed description of illustrative embodiments which is to be read in connection with the accompanying drawings.
REFERENCES:
patent: 5727212 (1998-03-01), Dinallo
patent: 6121981 (2000-09-01), Trower, II et al.
patent: 6148346 (2000-11-01), Hanson
patent: 6243753 (2001-06-01), Machin et al.
patent: 6425017 (2002-07-01), Dievendorff et al.
patent: 0 778 688 (1997-06-01), None
Frommer William S.
Frommer & Lawrence & Haug LLP
Nguyen Cao (Kevin)
Smid Dennis M.
Sony United Kingdom Limited
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