Browse Prior Art Database

Constraint-Based Method for Representing and Operating on a Graphical Primitive

IP.com Disclosure Number: IPCOM000105186D
Original Publication Date: 1993-Jun-01
Included in the Prior Art Database: 2005-Mar-19
Document File: 4 page(s) / 58K

Publishing Venue

IBM

Related People

Miyazawa, A: AUTHOR

Abstract

A new method is described for representing and operating on a graphical object defined on a two-dimensional plane. The technique allows several graphical operations on a line segment, such as rubber-band, rotate, scale, and move, without first putting the graphics system into a corresponding mode for updating the object being altered. This technique contrasts with conventional modal operations for editing objects, in which the user must first enter an appropriate mode, say by choosing a command from a menu, and then edit an object in a different way from that in which he performed the last operation.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 75% of the total text.

Constraint-Based Method for Representing and Operating on a Graphical Primitive

      A new method is described for representing and operating on a
graphical object defined on a two-dimensional plane.  The technique
allows several graphical operations on a line segment, such as
rubber-band, rotate, scale, and move, without first putting the
graphics system into a corresponding mode for updating the object
being altered.  This technique contrasts with conventional modal
operations for editing objects, in which the user must first enter an
appropriate mode, say by choosing a command from a menu, and then
edit an object in a different way from that in which he performed the
last operation.

      The new method reported here for representing a line segment
uses three kinds of handle appearing associated with the object,
which indicate the positions of both its ends and the length and
direction of the line, respectively, as shown in Fig. 1.  Although a
straight line, in general, may be defined by a starting point and an
ending point, it may also be uniquely determined by its starting
point, length, and direction.  Thus, the proposed representation is
complete from a mathematical point of view.

      The most important aspect of the operating method is the
inclusion of constraints and constraint definition mechanisms.  By
performing double-click technique, for example, the user can place a
constraint on one of the handles to specify that the handle is fixed
or...