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Constraint Hierarchies
 LISP AND SYMBOLIC COMPUTATION
, 1992
"... Constraints allow programmers and users to state declaratively a relation that should be maintained, rather than requiring them to write procedures to maintain the relation themselves. They are thus useful in such applications as programming languages, user interface toolkits, and simulation package ..."
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Cited by 144 (14 self)
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Constraints allow programmers and users to state declaratively a relation that should be maintained, rather than requiring them to write procedures to maintain the relation themselves. They are thus useful in such applications as programming languages, user interface toolkits, and simulation packages. In many situations, it is desirable to be able to state both required and preferential constraints. The required constraints must hold. Since the other constraints are merely preferences, the system should try to satisfy them if possible, but no error condition arises if it cannot. A constraint hierarchy consists of a set of constraints, each labeled as either required or preferred at some strength. An arbitrary number of different strengths is allowed. In the discussion of a theory of constraint hierarchies, we present alternate ways of selecting among competing possible solutions, and prove a number of propositions about the relations among these alternatives. We then outline algorit...
The Movable Filter as a User Interface Tool
, 1994
"... Magic Lens filters are a new user interface tool that combine an arbitrarilyshaped region with an operator that changes the view of objects viewed through that region. These tools can be interactively positioned over onscreen applications much as a magnifying glass is moved over a newspaper. They ..."
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Cited by 101 (1 self)
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Magic Lens filters are a new user interface tool that combine an arbitrarilyshaped region with an operator that changes the view of objects viewed through that region. These tools can be interactively positioned over onscreen applications much as a magnifying glass is moved over a newspaper. They can be used to help the user understand various types of information, from text documents to scientific visualizations. Because these filters are movable and apply to only part of the screen, they have a number of advantages over traditional windowwide viewing modes: they employ an attractive metaphor based on physical lenses, show a modified view in the context of the original view, limit clutter to a small region, allow easy construction of visual macros and provide a uniform paradigm that can be extended across different types of information and applications. This paper describes these advantages in more detail and illustrates them with examples of magic lens filters in use over a variety...
Multiway versus Oneway Constraints in User Interfaces: Experience with the DeltaBlue Algorithm
, 1993
"... this paper we argue that many user interface construction problems are handled more naturally and elegantly by multiway constraints than by oneway constraints. We present pseudocode for an incremental multiway constraint satisfaction algorithm, DeltaBlue, and describe experience in using the algo ..."
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Cited by 83 (17 self)
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this paper we argue that many user interface construction problems are handled more naturally and elegantly by multiway constraints than by oneway constraints. We present pseudocode for an incremental multiway constraint satisfaction algorithm, DeltaBlue, and describe experience in using the algorithm in two user interface toolkits. Finally, we provide performance figures demonstrating that multiway constraint solvers can be entirely competitive in performance with oneway constraint solvers
Hierarchical Constraint Logic Programming
, 1993
"... A constraint describes a relation to be maintained ..."
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Cited by 67 (3 self)
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A constraint describes a relation to be maintained
Constraint Hierarchies and Logic Programming
, 1989
"... Constraint Logic Programming (CLP) is a general scheme for extending logic programming to include constraints. It is parameterized by D, the domain of the constraints. However, CLP(D) languages, as well as most other constraint systems, only allow the programmer to specify constraints that must hold ..."
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Cited by 67 (5 self)
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Constraint Logic Programming (CLP) is a general scheme for extending logic programming to include constraints. It is parameterized by D, the domain of the constraints. However, CLP(D) languages, as well as most other constraint systems, only allow the programmer to specify constraints that must hold. In many applications, such as interactive graphics, page layout, and decision support, one needs to express preferences as well as strict requirements. If we wish to make full use of the constraint paradigm, we need ways to represent these defaults and preferences declaratively, as constraints, rather than encoding them in the procedural parts of the language. We describe a scheme for extending CLP(D) to include both required and preferential constraints, with an arbitrary number of strengths of preference. We present some of the theory of such languages, and an algorithm for executing them. To test our ideas, we have implemented an interpreter for an instance of this language scheme with D equal to the reals. We describe our interpreter, and outline some examples of using this language.
A Framework for Information Visualization Spreadsheets
, 1999
"... Information has become interactive. Information visualization is the design and creation of interactive graphic depictions of information by combining principles in the disciplines of graphic design, cognitive science, and interactive computer graphics. As the volume and complexity of the data incre ..."
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Cited by 62 (3 self)
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Information has become interactive. Information visualization is the design and creation of interactive graphic depictions of information by combining principles in the disciplines of graphic design, cognitive science, and interactive computer graphics. As the volume and complexity of the data increases, users require more powerful visualization tools that allow them to more effectively explore large abstract datasets. This
A Geometric Constraint Solver
, 1995
"... We report on the development of a twodimensional geometric constraint solver. The solver is a major component of a new generation of CAD systems that we are developing based on a highlevel geometry representation. The solver uses a graphreduction directed algebraic approach, and achieves interact ..."
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Cited by 60 (9 self)
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We report on the development of a twodimensional geometric constraint solver. The solver is a major component of a new generation of CAD systems that we are developing based on a highlevel geometry representation. The solver uses a graphreduction directed algebraic approach, and achieves interactive speed. We describe the architecture of the solver and its basic capabilities. Then, we discuss in detail how to extend the scope of the solver, with special emphasis placed on the theoretical and human factors involved in finding a solution  in an exponentially large search space  so that the solution is appropriate to the application and the way of finding it is intuitive to an untrained user. 1 Introduction Solving a system of geometric constraints is a problem that has been considered by several communities, and using different approaches. For example, the symbolic computation community has considered the general problem, in the Supported in part by ONR contract N0001490J...
Inferring Constraints from Multiple Snapshots
, 1993
"... Many graphics tasks, such as the manipulation of graphical objects, and the construction of userinterface widgets, can be facilitated by geometric constraints. However, the difficulty of specifying constraints by traditional methods forms a barrier to their widespread use. In order to make constrain ..."
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Cited by 42 (2 self)
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Many graphics tasks, such as the manipulation of graphical objects, and the construction of userinterface widgets, can be facilitated by geometric constraints. However, the difficulty of specifying constraints by traditional methods forms a barrier to their widespread use. In order to make constraints easier to declare, we have developed a method of specifying constraints implicitly, through multiple examples. Snapshots are taken of an initial scene configuration, and one or more additional snapshots are taken after the scene has been edited into other valid configurations. The constraints that are satisfied in all the snapshots are then applied to the scene objects. We discuss an efficient algorithm for inferring constraints from multiple snapshots. The algorithm has been incorporated into the Chimera editor, and several examples of its use are discussed.
TBAG: A Highlevel Framework for Interactive, Animated 3D Graphics Applications
, 1994
"... We present a paradigm and toolkit for rapid prototyping of interactive, animated 3D graphics programs. The paradigm has its roots in declarative programming, emphasizing immutable values, first class functions, and relations, applying these concepts to a broad range of types, including points, vecto ..."
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Cited by 38 (6 self)
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We present a paradigm and toolkit for rapid prototyping of interactive, animated 3D graphics programs. The paradigm has its roots in declarative programming, emphasizing immutable values, first class functions, and relations, applying these concepts to a broad range of types, including points, vectors, planes, colors, transforms, geometry, and sound. The narrow role of modifiable state in this paradigm allows applications to be run in a collaborative setting (multiuser and multicomputer) without modification. CR Categories and Subject Descriptors: I.3.7 [Computer Graphics]: ThreeDimensional Graphics and Realism; I.3.6 [Computer Graphics]: Methodology and Techniques; D.1.1 [Pro gramming Techniques] Applicative (Functional) Programming; D.2.m [Software Engineering] Miscellaneous Rapid Prototyping; G.1.7 [Mathematics of Computing] Ordinary Differential Equations. Additional Keywords and Phrases: Local Propagation Constraints 1 Introduction TBAG is a paradigm and toolkit for ra...
Geometric constraint solving
 Computing in Euclidean Geometry
, 1995
"... We survey the current state of the art in geometric constraint solving. Both 2D and 3D constraint solving is considered, and different approaches are characterized. ..."
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Cited by 31 (3 self)
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We survey the current state of the art in geometric constraint solving. Both 2D and 3D constraint solving is considered, and different approaches are characterized.