FitTestDoc.tioga
Stone, September 25, 1987 5:47:50 pm PDT
Maureen Stone, September 25, 1987 6:13:01 pm PDT
FitTest
CEDAR 7.0 — FOR INTERNAL XEROX USE ONLY
FitTest
Simple Curve Editor
Maureen Stone, Michael Plass
© Copyright 1987 Xerox Corporation. All rights reserved.
Abstract: A simple tool for testing the sketch and fit paradigm of curve editing
Created by: Maureen Stone and Michael Plass
Maintained by: Maureen Stone <Stone.PA>
Keywords: Curve Editing, Curve Fitting, Hacks
XEROX   Xerox Corporation
    Palo Alto Research Center
    3333 Coyote Hill Road
    Palo Alto, California 94304

For Internal Xerox Use Only
1. Motivation
For many years people have been editing curves by manipulating control points. Most people don't like it, but it's all they've got. We're working towards a paradigm that allows the user to sketch a curve, automatically convert the samples to a synthetic form, then edit the curve, all without touching a control point. This simple tool is a first step in that effort. As ideas become more concrete, they will migrate to Gargoyle
2. To Use It
Type FitTest to run a comand file. This will create a viewer on a test file. If you want to rename the viewer, use a full path name. This tool is currently very dumb. We should eventually integrate Fit into SampledCurveEdit, clean it up and release it.
3. SampledCurveEdit
SampledCurveEdit is a simple point editor written by Michael Plass. The user sketches a sequence of points, then manipulates selected sets of points to achieve the desired shape. The TIP table contains many wonderful features. The most useful are:
LeftMouse: Select points  LeftShift-LeftMouse: Add points
MiddleMouse: Select trajectory  LeftShift-MiddleMouse: Move selected points
RightMouse: Extend selection
TabMiddleMouse: Smoothly deforms the selected set of samples to bulge in the direction of motion. Try it.
S: Smooth the selected samples (identical to smooth button on the menu)
D: Double the number of points in the selection
ShiftD: Half the number of points in the selection
DEL: Delete the selected points
4. Fit
The FitCubics button on the tool fits a sequence of cubic pieces through the samples. Tangent continuity is maintained. To change the tightness/looseness of the fit, type to the CommandTool:
← FitTestImpl.metrics.maxDev ← <some number>
The current value for maxDev is 2. A larger number produces a looser fit.
5. Misc
To see the intermediate cubics generated during fitting, type:
← LSPieceImpl.debug ← TRUE