Tracking the mouse

The most numerous and best-developed set of interactors in Tycho are those that "track" movement of the mouse in some way. These interactors can all be cascaded -- for example, cascading a Bounder with a Stepper will move an item in discrete steps and keep it within a region of the Slate.

Follower

Follower just follows the mouse exactly. It is the most basic kind of mouse tracker, and is the superclass of all other mouse trackers. It has no options other than those in the Interactor superclass.

Enhancements: (none)

Bounder

Bounder moves an item, but keeps it within a rectangular region of the Slate. It has the following options Note that the bounds enforced by this interactor apply to the target item, not to the cursor. That is, the interactor keeps the target within the specified region, which usually means that the cursor is restricted to any even smaller region. If the target item is outside the bounds when the interactor is activated, the first movement will move it inside the bounds.

Enhancements: It is uncertain what will happen if the bounds is smaller than the target item.

Alonger

Alonger is similar to Bounder, but moves the target item in one axis only. It has the following options The remarks made about Bounder keeping the target item, not the cursor, within the bounds also apply to Alonger.

Enhancements: This interactor needs a better name.

Gridder and Stepper

Gridder and Stepper quantize the mouse movement. They have the following option: Gridder and Stepper are almost the same, except that Gridder forces the cursor to multiples of the gridsize, while Stepper quantizes the cursor movement to steps equal to that amount. For example, suppose gridsize were 10 and the start position of the cursor was (15,15). Gridder would move the cursor to say (20,20) and then (30,20), while Stepper would move it to say (25,25) and then (35,25).

Enhancements: Merge Gridder into Stepper, and provide a flag that selects no quantization, gridding, or stepping.

Back up
Tycho Home Page


Copyright © 1996, The Regents of the University of California. All rights reserved.
Last updated: 96/12/11, comments to: johnr@eecs.berkeley.edu