sjm.examples.sling
Class Scale

java.lang.Object
  |
  +--sjm.examples.sling.SlingFunction
        |
        +--sjm.examples.sling.Scale

public class Scale

extends SlingFunction

A scale represents the relationship of two temporal variables that vary linearly with each other. In Sling, the most common example of a scale is the relationship of user coordinates to panel coordinates. For example, in plotting a unit circle, a square that bounds the circle has its minimum point at (-1, -1), and its maximum at (1, 1). The minimum is at the lower left corner, where the panel coordinate might be (52.0, 262.0). The maximum is at the upper right, where the panel coordinate might be (314.0, 0.0). If c is a circle function in user coordinates, then the following definition will create s as a function that returns the panel coordinate as a function of time:

 
     Scale s = 
         new Scale(min, c, max, lowerLeft, upperRight); 
 

The function s maps every point on the user's circle to a point on the panel.

Fields inherited from class sjm.examples.sling.SlingFunction

source

Constructor Summary

Scale()
Constructs a scale with the right number of arguments, which is useful for a prototypical scale.

Scale(SlingFunction bFrom, SlingFunction bTo)
Constructs scale((0, 0), t, (1, 1), bFrom, bTo) .

Scale(SlingFunction aFrom, SlingFunction a, SlingFunction aTo, SlingFunction bFrom, SlingFunction bTo)
Constructs scale(aFrom, a, aTo, bFrom, bTo).

Method Summary

Point	f(double t) Given the source functions aFrom, a, aTo, bFrom and bTo, this function varies from bFrom to bTo as "a" varies from aFrom to aTo.
protected double	linear(double aFrom, double a, double aTo, double bFrom, double bTo)
java.lang.String	toString() Return a string representation of this function.

Methods inherited from class sjm.examples.sling.SlingFunction

eval, extrema, fresh

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

Scale

public Scale()

Constructs a scale with the right number of arguments, which is useful for a prototypical scale.

Scale

public Scale(SlingFunction bFrom,
             SlingFunction bTo)

Constructs scale((0, 0), t, (1, 1), bFrom, bTo) .

Parameters:

bFrom - a SlingFunction (usually a Point) that establishes the "from" bound for some variable b, which this scale represents

bTo - a SlingFunction (also usually a Point) that establishes the "to" bound for the variable.

Scale

public Scale(SlingFunction aFrom,
             SlingFunction a,
             SlingFunction aTo,
             SlingFunction bFrom,
             SlingFunction bTo)

Constructs scale(aFrom, a, aTo, bFrom, bTo). The returned scale varies from bFrom to bTo as "a" varies from aFrom to aTo. The "from" and "to" functions are usually points, so that the returned scale maps between two sets of coordinates.

Method Detail

f

public Point f(double t)

Given the source functions aFrom, a, aTo, bFrom and bTo, this function varies from bFrom to bTo as "a" varies from aFrom to aTo.

Overrides:

f in class SlingFunction

Parameters:

t - a number that represents how far along a plot is, and thus tells which point to return

Returns:

a new point b, that maps a.f(t) into the scale for b

linear

protected double linear(double aFrom,
                        double a,
                        double aTo,
                        double bFrom,
                        double bTo)

toString

public java.lang.String toString()

Return a string representation of this function.

Overrides:

toString in class java.lang.Object