think-cell technical report TC2003/01 A GUI-based Interaction ...

4.1 A New Approach to Slide Layout INTERACTION CONCEPT
User interaction
User interaction
User think-cell add-in
Micosoft PowerPoint
Figure 10: The user’s view: The think-cell add-in helps to quickly generate satisfying
results in Microsoft PowerPoint. Besides the specific UI widgets, all PowerPoint
features behave as usual.
With these observations in mind, the extension of PowerPoint with some auto-
mated layout optimization technique appears promising. The user should be able
to specify intentions, which are recognized by the program as numeric constraints.
Constraints can be solved and the intended layout can be arranged by the computer.
Moreover, when part of the composition is changed by the user, the over-all layout
can be updated to preserve the constraints that were specified earlier.
The think-cell layout add-in for Microsoft PowerPoint provides these features.
From the user’s point of view, the think-cell software adds some new UI widgets
to the Microsoft PowerPoint user interface (Fig. 10), while the rest of PowerPoint
looks and behaves just the way it always did.
The challenge of this approach is to model the characteristics of optimal layout in
a way that can be computationally solved. This leads to the idea of a “smart grid”:
Constraints that can be expressed by a grid-like structure are almost sufficient to
describe a layout model for business slides.
4.1.2 The Smart Grid Concept
The smart grid concept provides an abstraction from exact pixel positions and
absolute sizes. The additional abstraction layer simplifies user input, requiring
greater machine work to interpret the input and to translate the user’s incomplete
layout specification into a fully specified slide layout. The gap between the abstract,
incomplete layout specification and the final layout is bridged by generic constraints
that formalize design rules for esthetic layout.
Figure 11 provides an overview of the automation process. This work focuses
on the user interaction, whereas the solving of numeric constraints that is required
to implement a self-adjusting smart grid is beyond the scope of my thesis.
Terminology
The smart grid is a dual concept based on smart gridlines and smart elements.
Figure 12 visualizes how the components of the concept interact. Smart elements
are bound to horizontal and vertical gridlines; elements that are bound to the same
gridline are effectively aligned.
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