net.sourceforge.webcompmath.draw
Class RationalLabel

java.lang.Object
  net.sourceforge.webcompmath.draw.RationalLabel

public class RationalLabel
extends java.lang.Object

RationalLabels provide a way to label an axis with fractions, with an optional constant factor such as pi. The class adjusts for special cases:

1) the numerator is zero

2) the denominator is one (and hence no fraction is needed)

3) there is a factor and the numerator is 1; in this case, the factor is placed in the numerator (i.e., it shows pi/2 instead of 1/2 pi)

4) if it is negative and a fraction is needed, the minus sign is placed in front of the fractions (not in the numerator)

To use, create a RationalLabel, then call its drawFraction method. You can also use getBounds to find out how big it will be (useful when labeling an axis to avoid crowding labels too close together).

Author:

Tom Downey

Nested Class Summary

static class	RationalLabel.HJust Specify the horizontal justification for the rational label
static class	RationalLabel.VJust Specify the vertical justification for the rational label

Field Summary

static java.lang.String

pi Used to represent pi

Constructor Summary

RationalLabel()
Default Constructor

RationalLabel(Fraction frac, java.lang.String factorString)
Construct a rational label.

Method Summary

void	drawFraction(java.awt.Graphics2D g2, int x, int y, RationalLabel.HJust hJust, RationalLabel.VJust vJust) Draws the rational label.
java.awt.geom.Rectangle2D	getBounds(java.awt.Graphics2D g2) This method returns a bounding rectangle for the rational label.
java.lang.String	getFactorString() Get the factor
Fraction	getFrac() Get the fraction
boolean	isRationalText() Get whether to use text or typeset label
void	setFactorString(java.lang.String factorString) Set the factor (does nothing if argument is null)
void	setFrac(Fraction frac) Set the fraction (does nothing if argument is null)
void	setRationalText(boolean rationalText) Set whether to use text or typeset label

Methods inherited from class java.lang.Object

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

Field Detail

pi

public static final java.lang.String pi

Used to represent pi

See Also:

Constant Field Values

Constructor Detail

RationalLabel

public RationalLabel()

Default Constructor

RationalLabel

public RationalLabel(Fraction frac,
                     java.lang.String factorString)

Construct a rational label. Does nothing if either argument is null

Parameters:

frac - the fraction to use for the label

factorString - the constant factor, usually "", but might be "e" or pi

Method Detail

getFactorString

public java.lang.String getFactorString()

Get the factor

Returns:

Returns the factorString.

setFactorString

public void setFactorString(java.lang.String factorString)

Set the factor (does nothing if argument is null)

Parameters:

factorString - The factorString to set.

getFrac

public Fraction getFrac()

Get the fraction

Returns:

Returns the frac.

setFrac

public void setFrac(Fraction frac)

Set the fraction (does nothing if argument is null)

Parameters:

frac - The frac to set.

isRationalText

public boolean isRationalText()

Get whether to use text or typeset label

Returns:

Returns the rationalText.

setRationalText

public void setRationalText(boolean rationalText)

Set whether to use text or typeset label

Parameters:

rationalText - true for text, false for typeset (default)

getBounds

public java.awt.geom.Rectangle2D getBounds(java.awt.Graphics2D g2)

This method returns a bounding rectangle for the rational label. The width and height are set to enclose the entire label, including the fraction, any leading minus sign, and any trailing factor. Like the bounds returned from Font.getStringBounds, x is always 0, and y is a negative number indicating the offset from the top to the baseline (i.e., y is -ascent).

Parameters:

g2 - the graphics context

Returns:

the bounding rectangle (float)

drawFraction

public void drawFraction(java.awt.Graphics2D g2,
                         int x,
                         int y,
                         RationalLabel.HJust hJust,
                         RationalLabel.VJust vJust)

Draws the rational label. x and y indicate a point, and hJust and vJust provide the justifications of the label relative to the point. If both are CENTER, then the label will be centered at the point. hJust=CENTER and vJust=TOP would be usefull for x axis labels that lie below the x axis and are top-justified. hJust=RIGHT and vJust=CENTER would be useful for y axis labels that lie to the left of the axis and are right justified.

Parameters:

g2 - the graphics context

x - the x coordinate of the point

y - the y coordinate of the point

hJust - the horizontal justification, CENTER, LEFT, or RIGHT

vJust - the vertical justification, CENTER, TOP, or BOTTOM