Pattern-Aware Selection and Arrangement of Graphic Elements

The Hong Kong University of Science and Technology
Department of Computer Science and Engineering


PhD Thesis Defence


Title: "Pattern-Aware Selection and Arrangement of Graphic Elements"

By

Mr. Pengfei XU


Abstract

Selection and arrangement of graphic elements are two fundamental tasks in 
many text and graphic editing scenarios. Traditional interactive 
techniques such as lasso selection, snapping and arrangement commands are 
provided by most graphic editors to aid the users in accomplishing these 
tasks. However, these techniques are often oblivious of the underlying 
patterns of the elements, requiring the users to perform explicit and 
tedious operations to achieve the goal of the manipulation. It is expected 
that the amount of user interaction can be reduced by exploiting the 
patterns of the elements. Nevertheless, designing effective pattern-aware 
interaction tools is challenging due to the ambiguities in the patterns 
represented by the elements and the operations issued by the user.

This thesis focuses on developing effective pattern-aware interactive 
techniques to aid the users in the selection and arrangement of elements.
In particular, we propose three interactive techniques which adopt 
different strategies to resolve the ambiguities arose during manipulation.

First, we introduce a selection tool called Lazy Selection. It is a 
scribble-based tool for quick selection of one or more desired shape 
elements by roughly stroking through the elements. Our algorithm 
automatically refines the selection and reveals the user's intention. It 
first extracts selection candidates from the scribble-covered elements by 
examining the underlying patterns and then ranks them based on their 
location and shape with respect to the user-sketched scribble. Such a 
design makes this tool tolerant to imprecise input systems and applicable 
to touch systems without suffering from the fat finger problem.

Second, we present GACA, a group-aware command-based arrangement tool. 
Compared with the traditional command-based arrangement tools, it reduces 
the numbers of selection operation and command invocation. The key idea is 
that an issued arrangement command is in fact very informative, 
instructing the command how to automatically decompose a 2D layout into 
multiple 1D groups, each of which being compatible with the command. We 
present a parameter-free, command-driven grouping approach so that users 
can easily predict our grouping results. We also design a simple user 
interface to enable explicit control of grouping and arrangement.

Third, we present a framework for automatic global beautification of 
layouts. To facilitate ambiguity resolution in layout beautification, we
present a novel user interface for visualizing and editing inferred 
relationships. Our interface provides a preview of the beautified layout 
with inferred constraints, without directly modifying the input layout. In 
this way, the user can easily keep refining beautification results by 
interactively repositioning and/or resizing elements in the input layout. 
In addition, we present a gestural interface for editing automatically 
inferred constraints by directly interacting with the visualized 
constraints via simple gestures.


Date:			Monday, 26 January 2015

Time:			3:00pm - 5:00pm

Venue:			Room 3494
 			Lifts 25/26

Chairman:		Prof. Jiang Xu (ECE)

Committee Members:	Prof. Chiew-Lan Tai (Supervisor)
 			Prof. Lei Chen
 			Prof. Albert Chung
 			Prof. Ajay Joneja (IELM)
 			Prof. Pheng-Ann Heng (Comp. Sci. & Engg., CUHK)


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