alignment

Despite the ubiquity of slide presentations, managing multiple presentations remains a challenge. Understanding how multiple versions of a presentation are related to one another, assembling new presentations from existing presentations, and collaborating to create and edit presentations are difficult tasks. In this paper, we explore techniques for comparing and managing multiple slide presentations. We propose a general comparison framework for computing similarities and differences between slides. Based on this framework we develop an interactive tool for visually comparing multiple presentations. The interactive visualization facilitates understanding how presentations have evolved over time. We show how the interactive tool can be used to assemble new presentations from a collection of older ones and to merge changes from multiple presentation authors.

We present an evaluation of three mouse-based techniques for aligning digital images. We investigate the physical image alignment task and discuss the implications for interacting with virtual images. In a formal evaluation we show that a symmetric bimanual technique outperforms an asymmetric bimanual technique which in turn outperforms a unimanual technique. We show that even after mode switching times are removed, the symmetric technique outperforms the single mouse technique. Subjects also exhibited more parallel interaction using the symmetric technique than when using the asymmetric technique.

Existing augmentations of web pages are mostly small cosmetic changes (e.g., removing ads) and minor addition of third-party content (e.g., product prices from competing sites). None leverages the structured data presented in web pages. This paper describes Sifter, a web browser extension that can augment a well-structured web site with advanced filtering and sorting functionality. These added features work inside the site's own pages, preserving the site's presentational style and the user's context. Sifter contains an algorithm that scrapes structured data out of well-structured web pages while usually requiring no user intervention. We tested Sifter on real web sites and real users and found that people could use Sifter to perform sophisticated queries and high-level analyses on sizable data collections on the Web. We propose that web sites can be similarly augmented with other sophisticated data-centric functionality, giving users new benefits over the existing Web.

Freehand sketching has long had appeal as an artistic medium for conceptual design because of its immediacy in capturing and communicating design intent and visual experience. We present a sketching paradigm that supports the early stages of design by preserving the fluidity of traditional freehand drawings. In addition, it attempts to fill the gap between 2D drawing programs, which have fixed views, and 3D modeling programs that allow arbitrary views. We implement our application as a two-dimensional drawing program that utilizes a projective representation of points --- i.e. points that lie on the surface of a unit sphere centered at the viewpoint. This representation facilitates the production of novel re-projections generated from an initial perspective sketch and gives the user the impression of being immersed in the drawing or space. We describe a method for aligning a sketch drawn outside the system using its vanishing points, allowing the integration of computer sketching and freehand sketching on paper in an iterative manner. The user interface provides a virtual camera, projective grids to guide in the construction of proportionate scenes, and the ability to underlay sketches with other drawings or photographic panoramas.