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Correlation Processor NAME STACK Format

IP.com Disclosure Number: IPCOM000060570D
Original Publication Date: 1986-Apr-01
Included in the Prior Art Database: 2005-Mar-08
Document File: 3 page(s) / 34K

Publishing Venue

IBM

Related People

Niblett, PD: AUTHOR [+2]

Abstract

This article describes a technique used to return full context information on each of a series of correlate hits which occur in a chained list of segments. A graphical picture may be defined as a collection of graphical segments. These segments are linked together to form a picture in two ways: o Chaining. The chained segments are drawn successively, each being completed before its successor is started. o Calling. A special drawing order within a segment can call up another segment in a manner similar to subroutine linkage in a programming language. When the called segment has been dealt with, processing resumes at the following order in the calling segment. A segment can be called more than once. A complex picture may use both forms of linkage, with a chain of 'root segments' and a set of dependents called segments.

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Correlation Processor NAME STACK Format

This article describes a technique used to return full context information on each of a series of correlate hits which occur in a chained list of segments. A graphical picture may be defined as a collection of graphical segments. These segments are linked together to form a picture in two ways: o Chaining. The chained segments are drawn successively, each being completed before its successor is started. o Calling. A special drawing order within a segment can call up another segment in a manner similar to subroutine linkage in a programming language. When the called segment has been dealt with, processing resumes at the following order in the calling segment. A segment can be called more than once. A complex picture may use both forms of linkage, with a chain of 'root segments' and a set of dependents called segments. This article describes the format of data returned by a correlation processor. This processor has to scan through the entire picture comparing the drawing primitives of which it is comprised against the pick window associated with a graphical pick device, for instance, a small rectangle positioned by the user on a display screen. The processor returns information about all primitives that intersect the window, including the contexts of these primitives within the picture. The notion of context is explained by the following example

(Image Omitted)

where '-->' denotes 'calls' The following table shows example contexts corresponding to each of these segments:

(Image Omitted)

The context information for each called segment may also reflect such data as the offset of the Call Segment order within the calling segment, values of attributes at that time, etc. This data is henceforth referred to as a 'C-block'. The correlation processor has a stack N which is set to EMPTY before correlation is started. After the segment chain has been correlated, N should determine each hit which occurred. For each hit N should determine: 1. A block of data (which may contain a "pick identifier", an offset, etc.), henceforth referred to as a 'P- block'. 2. The context in which the hit occurred, i.e., a sequence of C- blocks. THE METHOD The stack N is made up of C-blocks, P-blocks, root segment delimiters and pick delimiters. These elements are all distinguishable and have self-defining (possibly constant) lengths. The pick delimiter contains an integer return count. During the correlation process, the following actions are performed which affect N: o Chain to segment o Call segment o Return from segment o Detect hit The effect of each of these actions on N is now specified. CHAIN TO SEGMENT Push a root segment delimiter on to...