/*
* @(#)Ellipse2D.java 1.16 03/12/19
*
* Copyright 2004 Sun Microsystems, Inc. All rights reserved.
* SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
*/
package java.awt.geom;
/**
* The <code>Ellipse2D</code> class describes an ellipse that is defined
* by a bounding rectangle.
* <p>
* This class is only the abstract superclass for all objects which
* store a 2D ellipse.
* The actual storage representation of the coordinates is left to
* the subclass.
*
* @version 1.16, 12/19/03
* @author Jim Graham
*/
public abstract class Ellipse2D extends RectangularShape {
/**
* The <code>Float</code> class defines an ellipse specified
* in <code>float</code> precision.
*/
public static class Float extends Ellipse2D {
/**
* The x coordinate of the upper left corner of this
* <code>Ellipse2D</code>.
*/
public float x;
/**
* The y coordinate of the upper left corner of this
* <code>Ellipse2D</code>.
*/
public float y;
/**
* The overall width of this <code>Ellipse2D</code>.
*/
public float width;
/**
* The overall height of this <code>Ellipse2D</code>.
*/
public float height;
/**
* Constructs a new <code>Ellipse2D</code>, initialized to
* location (0, 0) and size (0, 0).
*/
public Float() {
}
/**
* Constructs and initializes an <code>Ellipse2D</code> from the
* specified coordinates.
* @param x, y the coordinates of the bounding rectangle
* @param w the width of the bounding rectangle
* @param h the height of the bounding rectangle
*/
public Float(float x, float y, float w, float h) {
setFrame(x, y, w, h);
}
/**
* Returns the X coordinate of the upper left corner of this
* <code>Ellipse2D</code> in <code>double</code> precision.
* @return the X coordinate of the upper left corner of the
* bounding rectangle of this <code>Ellipse2D</code>.
*/
public double getX() {
return (double) x;
}
/**
* Returns the Y coordinate of the upper left corner of this
* <code>Ellipse2D</code> in <code>double</code> precision.
* @return the Y coordinate of the upper left corner of the
* bounding rectangle of this <code>Ellipse2D</code>.
*/
public double getY() {
return (double) y;
}
/**
* Returns the overall width of this <code>Ellipse2D</code> in
* <code>double</code> precision.
* @return the width of this <code>Ellipse2D</code>.
*/
public double getWidth() {
return (double) width;
}
/**
* Returns the overall height of this <code>Ellipse2D</code> in
* <code>double</code> precision.
* @return the height of this <code>Ellipse2D</code>.
*/
public double getHeight() {
return (double) height;
}
/**
* Determines whether or not the bounding box of this
* <code>Ellipse2D</code> is empty.
* @return <code>true</code> if the bounding rectangle of this
* <code>Ellipse2D</code> is empty; <code>false</code> otherwise.
*/
public boolean isEmpty() {
return (width <= 0.0 || height <= 0.0);
}
/**
* Sets the location and size of this <code>Ellipse2D</code> to
* the specified <code>float</code> values.
* @param x, y the specified coordinates to which to set
* the location of the bounding box of this <code>Ellipse2D</code>
* @param w the specified width to which to set the width of
* this <code>Ellipse2D</code>
* @param h the specified height to which to set the height of
* the <code>Ellipse2D</code>
*/
public void setFrame(float x, float y, float w, float h) {
this.x = x;
this.y = y;
this.width = w;
this.height = h;
}
/**
* Sets the location and size of this <code>Ellipse2D</code> to
* the specified <code>double</code> values.
* @param x, y the specified coordinates to which to set
* the location of the bounding box of this <code>Ellipse2D</code>
* @param w the specified width to which to set the width of
* this <code>Ellipse2D</code>
* @param h the specified height to which to set the height of
* this <code>Ellipse2D</code>
*/
public void setFrame(double x, double y, double w, double h) {
this.x = (float) x;
this.y = (float) y;
this.width = (float) w;
this.height = (float) h;
}
/**
* Returns the high precision bounding box of this
* <code>Ellipse2D</code>.
* @return a {@link Rectangle2D} that is the bounding box
* of this <code>Ellipse2D</code>.
*/
public Rectangle2D getBounds2D() {
return new Rectangle2D.Float(x, y, width, height);
}
}
/**
* The <code>Double</code> class defines an ellipse specified
* in <code>double</code> precision.
*/
public static class Double extends Ellipse2D {
/**
* The x coordinate of the upper left corner of this
* <code>Ellipse2D</code>.
*/
public double x;
/**
* The y coordinate of the upper left corner of this
* <code>Ellipse2D</code>.
*/
public double y;
/**
* The overall width of this <code>Ellipse2D</code>.
*/
public double width;
/**
* The overall height of the <code>Ellipse2D</code>.
*/
public double height;
/**
* Constructs a new <code>Ellipse2D</code>, initialized to
* location (0, 0) and size (0, 0).
*/
public Double() {
}
/**
* Constructs and initializes an <code>Ellipse2D</code> from the
* specified coordinates.
* @param x, y the coordinates of the bounding rectangle
* @param w the width of the rectangle
* @param h the height of the rectangle
*/
public Double(double x, double y, double w, double h) {
setFrame(x, y, w, h);
}
/**
* Returns the X coordinate of the upper left corner of this
* <code>Ellipse2D</code> in <code>double</code> precision.
* @return the X coordinate of the upper left corner of
* the bounding box of this <code>Ellipse2D</code>.
*/
public double getX() {
return x;
}
/**
* Returns the Y coordinate of the upper left corner of this
* <code>Ellipse2D</code> in <code>double</code> precision.
* @return the Y coordinate of the upper left corner of
* the bounding box of this <code>Ellipse2D</code>.
*/
public double getY() {
return y;
}
/**
* Returns the overall width of this <code>Ellipse2D</code>
* in <code>double</code> precision.
* @return the width of this <code>Ellipse2D</code>.
*/
public double getWidth() {
return width;
}
/**
* Returns the overall height of this <code>Ellipse2D</code>
* in <code>double</code> precision.
* @return the height of this <code>Ellipse2D</code>.
*/
public double getHeight() {
return height;
}
/**
* Determines whether or not the bounding box of this
* <code>Ellipse2D</code> is empty.
* @return <code>true</code> if the bounding box of this
* <code>Ellipse2D</code> is empty;
* <code>false</code> otherwise.
*/
public boolean isEmpty() {
return (width <= 0.0 || height <= 0.0);
}
/**
* Sets the location and size of this <code>Ellipse2D</code>
* to the specified <code>double</code> values.
* @param x, y the specified coordinates to which to set
* the location of the bounding box of this <code>Ellipse2D</code>
* @param w the width to which to set the width of this
* <code>Ellipse2D</code>
* @param h the height to which to set the height of this
* <code>Ellipse2D</code>
*/
public void setFrame(double x, double y, double w, double h) {
this.x = x;
this.y = y;
this.width = w;
this.height = h;
}
/**
* Returns the high precision bounding box of this
* <code>Ellipse2D</code>.
* @return a <code>Rectangle2D</code> that is the bounding
* box of this <code>Ellipse2D</code>.
*/
public Rectangle2D getBounds2D() {
return new Rectangle2D.Double(x, y, width, height);
}
}
/**
* This is an abstract class that cannot be instantiated directly.
* Type-specific implementation subclasses are available for
* instantiation and provide a number of formats for storing
* the information necessary to satisfy the various accessor
* methods below.
*
* @see java.awt.geom.Ellipse2D.Float
* @see java.awt.geom.Ellipse2D.Double
*/
protected Ellipse2D() {
}
/**
* Tests if a specified point is inside the boundary of this
* <code>Ellipse2D</code>.
* @param x, y the coordinates to test
* @return <code>true</code> if the specified point is contained
* in this ellipse; <code>false</code> otherwise.
*/
public boolean contains(double x, double y) {
// Normalize the coordinates compared to the ellipse
// having a center at 0,0 and a radius of 0.5.
double ellw = getWidth();
if (ellw <= 0.0) {
return false;
}
double normx = (x - getX()) / ellw - 0.5;
double ellh = getHeight();
if (ellh <= 0.0) {
return false;
}
double normy = (y - getY()) / ellh - 0.5;
return (normx * normx + normy * normy) < 0.25;
}
/**
* Tests if the interior of this <code>Ellipse2D</code> intersects
* the interior of a specified rectangular area.
* @param x, y the coordinates of the upper left corner of the
* specified rectangular area
* @param w the width of the specified rectangular area
* @param h the height of the specified rectangluar area
* @return <code>true</code> if this <code>Ellipse2D</code> contains
* the specified rectangular area; <code>false</code> otherwise.
*/
public boolean intersects(double x, double y, double w, double h) {
if (w <= 0.0 || h <= 0.0) {
return false;
}
// Normalize the rectangular coordinates compared to the ellipse
// having a center at 0,0 and a radius of 0.5.
double ellw = getWidth();
if (ellw <= 0.0) {
return false;
}
double normx0 = (x - getX()) / ellw - 0.5;
double normx1 = normx0 + w / ellw;
double ellh = getHeight();
if (ellh <= 0.0) {
return false;
}
double normy0 = (y - getY()) / ellh - 0.5;
double normy1 = normy0 + h / ellh;
// find nearest x (left edge, right edge, 0.0)
// find nearest y (top edge, bottom edge, 0.0)
// if nearest x,y is inside circle of radius 0.5, then intersects
double nearx, neary;
if (normx0 > 0.0) {
// center to left of X extents
nearx = normx0;
} else if (normx1 < 0.0) {
// center to right of X extents
nearx = normx1;
} else {
nearx = 0.0;
}
if (normy0 > 0.0) {
// center above Y extents
neary = normy0;
} else if (normy1 < 0.0) {
// center below Y extents
neary = normy1;
} else {
neary = 0.0;
}
return (nearx * nearx + neary * neary) < 0.25;
}
/**
* Tests if the interior of this <code>Ellipse2D</code> entirely
* contains the specified rectangular area.
* @param x, y the coordinates of the upper left corner of the
* specified rectangular area
* @param w the width of the specified rectangular area
* @param h the height of the specified rectangular area
* @return <code>true</code> if this <code>Ellipse2D</code> contains
* the specified rectangular area; <code>false</code> otherwise.
*/
public boolean contains(double x, double y, double w, double h) {
return (contains(x, y) &&
contains(x + w, y) &&
contains(x, y + h) &&
contains(x + w, y + h));
}
/**
* Returns an iteration object that defines the boundary of this
* <code>Ellipse2D</code>.
* The iterator for this class is multi-threaded safe, which means
* that this <code>Ellipse2D</code> class guarantees that
* modifications to the geometry of this <code>Ellipse2D</code>
* object do not affect any iterations of that geometry that
* are already in process.
* @param at an optional <code>AffineTransform</code> to be applied to
* the coordinates as they are returned in the iteration, or
* <code>null</code> if untransformed coordinates are desired
* @return the <code>PathIterator</code> object that returns the
* geometry of the outline of this <code>Ellipse2D</code>,
* one segment at a time.
*/
public PathIterator getPathIterator(AffineTransform at) {
return new EllipseIterator(this, at);
}
}
|
