Design and evaluation of the alignment stick
Object alignment is one of the basic operations in drawing programs. Current solutions provide mainly three ways for carrying out this operation: either by issuing an alignment command, or by using direct positioning with the help of gravity active points, or by making use of constraints. The first technique has limited functionality, and the other two may be difficult to learn for a novice. We describe here a new direct manipulation tool for alignment. We show that while direct manipulation helps to make the normal use of the tool intuitive, it also offers advanced functionality not found in current commercial products. We report on an empirical study in which we compared the ease of use, intuitiveness, learnability, and efficiency of alignment menus, palettes and the alignment stick. In the study novice users found the basic operation of the alignment stick natural and easy to learn. The increased functionality was best appreciated and utilized by the experienced users. (C) 2000 Elsevier Science B.V. All rights reserved.
alignment stick drawing programs direct manipulation menus alignment tools tool palettes two-handed interaction empirical tests