edu.hws.jcm.draw

Class ParametricCurve

java.lang.Object

edu.hws.jcm.draw.Drawable

edu.hws.jcm.draw.ParametricCurve

All Implemented Interfaces:

Computable, Serializable

public class ParametricCurve
extends Drawable
implements Computable

A ParametricCurve is defined by two functions, x(t) and y(t) of a variable, t, for t in a specified interval. The curve is simply defined as a sequence of line segments connecting points of the form (x(t),y(t)), except where one of the functions is undefined. Also, in some cases a discontinuity will be detected and no line will be drawn between two of the points.

See Also:

Serialized Form

Field Summary

Fields inherited from class edu.hws.jcm.draw.Drawable

canvas, coords

Constructor Summary

Constructors

Constructor and Description
ParametricCurve() Create a ParametricCurve with nothing to graph.
ParametricCurve(Function xFunc, Function yFunc) Create a parametric curve with x and y coordinates given by the specified functions of the parameter t.
ParametricCurve(Function xFunc, Function yFunc, Value tmin, Value tmax, Value intevals) Create a parametric curve with the specified values.

Method Summary

Modifier and Type	Method and Description
void	compute() Recompute data for the graph and make sure that the area of the display canvas that shows the graph is redrawn.
void	draw(Graphics g, boolean coordsChanged) Draw the graph (possibly recomputing the data if the CoordinateRect has changed).
Color	getColor() Get the color that is used to draw the graph.
Value	getIntervals() Get the value object, possibly null, that determines the number of points on the curve.
Value	getTMax() Get the Value object, possibly null, that gives the right endpoint of the domain of the parameter.
Value	getTMin() Get the Value object, possibly null, that gives the left endpoint of the domain of the parameter.
Function	getXFunction() Get the (possibly null) function that gives the x-coordinate of the curve.
Function	getYFunction() Get the (possibly null) function that gives the y-coordinate of the curve.
void	setColor(Color c) Set the color to be used for drawing the graph.
void	setFunctions(Function x, Function y) Sets the functions that gives the coordinates of the curve to be graphed.
void	setIntervals(Value intervalCount) Specify the number of subintervals into which the domain of the parametric curve is divided.
void	setLimits(Value tmin, Value tmax) Set the Value objects that specify the domain of the paratmeter.
void	setTMax(Value tmax) Set the Value object that gives the right endpoint of the domain of the parameter.
void	setTMin(Value tmin) Set the Value object that gives the left endpoint of the domain of the parameter.
void	setXFunction(Function x) Set the function that gives the x-coordinate of the curve to be graphed.
void	setYFunction(Function y) Set the function that gives the y-coordinate of the curve to be graphed.

Methods inherited from class edu.hws.jcm.draw.Drawable

getVisible, needsRedraw, setOwnerData, setVisible

Methods inherited from class java.lang.Object

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

Constructor Detail

ParametricCurve

public ParametricCurve()

Create a ParametricCurve with nothing to graph. The functions and other values can be set later.

ParametricCurve

public ParametricCurve(Function xFunc,
                       Function yFunc)

Create a parametric curve with x and y coordinates given by the specified functions of the parameter t. Defaults values are used for tmin, tmax, and the number of intervals. If either function is null, nothing is drawn.

ParametricCurve

public ParametricCurve(Function xFunc,
                       Function yFunc,
                       Value tmin,
                       Value tmax,
                       Value intevals)

Create a parametric curve with the specified values.

Parameters:

xFunc - A Function of one variable giving the x-coordinate of points on the curve. If this is null, then nothing will be drawn.

yFunc - A Function of one variable giving the y-coordinate of points on the curve. If this is null, then nothing will be drawn.

tmin - A Value object giving one endpoint of the domain of the parameter. If this is null, the default value -5 is used.

tmax - A Value object giving the second endpoint of the domain of the parameter. If this is null, the default value 5 is used. Note that it is not required that tmax be greater than tmin.

intervals - A Value object giving the number of intervals into which the domain is subdivided. If this is null, the default value 200 is used. The number of points on the curve will be the number of intervals plus one (unless a function is undefined at some value of the parameter or if a discontinuity is detected). The number of intervals is clamped to the range 1 to 10000. Values outside this range would certainly be unreasonable.

Method Detail

setColor

public void setColor(Color c)

Set the color to be used for drawing the graph.

getColor

public Color getColor()

Get the color that is used to draw the graph.

setFunctions

public void setFunctions(Function x,
                         Function y)

Sets the functions that gives the coordinates of the curve to be graphed. If either function is null, then nothing is drawn. If non-null, each function must be a function of one variable.

setXFunction

public void setXFunction(Function x)

Set the function that gives the x-coordinate of the curve to be graphed. If this is null, then nothing is drawn. If non-null, it must be a function of one variable.

setYFunction

public void setYFunction(Function y)

Set the function that gives the y-coordinate of the curve to be graphed. If this is null, then nothing is drawn. If non-null, it must be a function of one variable.

getXFunction

public Function getXFunction()

Get the (possibly null) function that gives the x-coordinate of the curve.

getYFunction

public Function getYFunction()

Get the (possibly null) function that gives the y-coordinate of the curve.

setIntervals

public void setIntervals(Value intervalCount)

Specify the number of subintervals into which the domain of the parametric curve is divided. The interval (tmin,tmax) is divided into subintervals. X and y coordinates of the parametric curve are computed at each endpoint of these subintervals, and then the points are connected by lines. If the parameter of this function is null, or if no interval count is ever specified, then a default value of 200 is used.

getIntervals

public Value getIntervals()

Get the value object, possibly null, that determines the number of points on the curve.

setLimits

public void setLimits(Value tmin,
                      Value tmax)

Set the Value objects that specify the domain of the paratmeter.

getTMin

public Value getTMin()

Get the Value object, possibly null, that gives the left endpoint of the domain of the parameter.

getTMax

public Value getTMax()

Get the Value object, possibly null, that gives the right endpoint of the domain of the parameter.

setTMin

public void setTMin(Value tmin)

Set the Value object that gives the left endpoint of the domain of the parameter. If this is null, then a default value of -5 is used for the left endpoint. (Note: actually, it's not required that tmin be less than tmax, so this might really be the "right" endpoint.)

setTMax

public void setTMax(Value tmax)

Set the Value object that gives the right endpoint of the domain of the parameter. If this is null, then a default value of 5 is used for the right endpoint. (Note: actually, it's not required that tmin be less than tmax, so this might really be the "left" endpoint.)

compute

public void compute()

Recompute data for the graph and make sure that the area of the display canvas that shows the graph is redrawn. This method is ordinarily called by a Controller.

Specified by:

compute in interface Computable

draw

public void draw(Graphics g,
                 boolean coordsChanged)

Draw the graph (possibly recomputing the data if the CoordinateRect has changed). This is not usually called directly.

Specified by:

draw in class Drawable

Parameters:

g - The graphics context in which the Drawble is to be drawn. (The drawing can change the color in g, but should not permanently change font, painting mode, etc. Thus, every drawable is responsible for setting the color it wants to use.)

coordsChanged - Indicates whether the CoordinateRect has changed.