diff options
Diffstat (limited to 'libjava/java/awt/geom/Ellipse2D.java')
| -rw-r--r-- | libjava/java/awt/geom/Ellipse2D.java | 225 |
1 files changed, 217 insertions, 8 deletions
diff --git a/libjava/java/awt/geom/Ellipse2D.java b/libjava/java/awt/geom/Ellipse2D.java index 223a1930991..bd64adf1e3a 100644 --- a/libjava/java/awt/geom/Ellipse2D.java +++ b/libjava/java/awt/geom/Ellipse2D.java @@ -1,5 +1,5 @@ /* Ellipse2D.java -- represents an ellipse in 2-D space - Copyright (C) 2000, 2002 Free Software Foundation + Copyright (C) 2000, 2002, 2004 Free Software Foundation This file is part of GNU Classpath. @@ -37,58 +37,153 @@ exception statement from your version. */ package java.awt.geom; + /** + * Ellipse2D is the shape of an ellipse. + * <BR> + * <img src="doc-files/Ellipse-1.png" width="347" height="221" + * alt="A drawing of an ellipse" /><BR> + * The ellipse is defined by it's bounding box (shown in red), + * and is defined by the implicit curve:<BR> + * <blockquote>(<i>x</i>/<i>a</i>)<sup>2</sup> + + * (<i>y</i>/<i>b</i>)<sup>2</sup> = 1<BR><BR> + * * @author Tom Tromey <tromey@cygnus.com> * @author Eric Blake <ebb9@email.byu.edu> + * * @since 1.2 - * @status still needs documentation */ public abstract class Ellipse2D extends RectangularShape { + /** + * Ellipse2D is defined as abstract. + * Implementing classes are Ellipse2D.Float and Ellipse2D.Double. + */ protected Ellipse2D() { } + /** + * Determines if a point is contained within the ellipse. <P> + * @param x - x coordinate of the point. + * @param y - y coordinate of the point. + * @return true if the point is within the ellipse, false otherwise. + */ public boolean contains(double x, double y) { double rx = getWidth() / 2; double ry = getHeight() / 2; - double tx = (x - getCenterX()) / rx; - double ty = (y - getCenterY()) / ry; - return tx * tx + ty * ty <= 1.0; + double tx = (x - (getX() + rx)) / rx; + double ty = (y - (getY() + ry)) / ry; + return tx * tx + ty * ty < 1.0; } + /** + * Determines if a rectangle is completely contained within the + * ellipse. <P> + * @param x - x coordinate of the upper-left corner of the rectangle + * @param y - y coordinate of the upper-left corner of the rectangle + * @param w - width of the rectangle + * @param h - height of the rectangle + * @return true if the rectangle is completely contained, false otherwise. + */ public boolean contains(double x, double y, double w, double h) { double x2 = x + w; double y2 = y + h; - return (contains(x, y) && contains(x, y2) - && contains(x2, y) && contains(x2, y2)); + return (contains(x, y) && contains(x, y2) && contains(x2, y) + && contains(x2, y2)); } + /** + * Returns a PathIterator object corresponding to the ellipse.<P> + * + * Note: An ellipse cannot be represented exactly in PathIterator + * segments, the outline is thefore approximated with cubic + * Bezier segments. + * + * @param at an optional transform. + * @return A path iterator. + */ public PathIterator getPathIterator(AffineTransform at) { // An ellipse is just a complete arc. return new Arc2D.ArcIterator(this, at); } + /** + * Determines if a rectangle intersects any part of the ellipse.<P> + * @param x - x coordinate of the upper-left corner of the rectangle + * @param y - y coordinate of the upper-left corner of the rectangle + * @param w - width of the rectangle + * @param h - height of the rectangle + * @return true if the rectangle intersects the ellipse, false otherwise. + */ public boolean intersects(double x, double y, double w, double h) { - // fixme + Rectangle2D r = new Rectangle2D.Double(x, y, w, h); + if (! r.intersects(getX(), getY(), getWidth(), getHeight())) + return false; + + if (contains(x, y) || contains(x, y + h) || contains(x + w, y) + || contains(x + w, y + h)) + return true; + + Line2D l1 = new Line2D.Double(getX(), getY() + (getHeight() / 2), + getX() + getWidth(), + getY() + (getHeight() / 2)); + Line2D l2 = new Line2D.Double(getX() + (getWidth() / 2), getY(), + getX() + (getWidth() / 2), + getY() + getHeight()); + + if (l1.intersects(r) || l2.intersects(r)) + return true; + return false; } + /** + * An {@link Ellipse2D} that stores its coordinates using <code>double</code> + * primitives. + */ public static class Double extends Ellipse2D { + /** + * The height of the ellipse. + */ public double height; + + /** + * The width of the ellipse. + */ public double width; + + /** + * The upper-left x coordinate of the bounding-box + */ public double x; + + /** + * The upper-left y coordinate of the bounding-box + */ public double y; + /** + * Creates a new Ellipse2D with an upper-left coordinate of (0,0) + * and a zero size. + */ public Double() { } + /** + * Creates a new Ellipse2D within a given rectangle + * using double-precision coordinates.<P> + * @param x - x coordinate of the upper-left of the bounding rectangle + * @param y - y coordinate of the upper-left of the bounding rectangle + * @param w - width of the ellipse + * @param h - height of the ellipse + */ public Double(double x, double y, double w, double h) { this.x = x; @@ -97,36 +192,72 @@ public abstract class Ellipse2D extends RectangularShape width = w; } + /** + * Returns the bounding-box of the ellipse. + * @return The bounding box. + */ public Rectangle2D getBounds2D() { return new Rectangle2D.Double(x, y, width, height); } + /** + * Returns the height of the ellipse. + * @return The height of the ellipse. + */ public double getHeight() { return height; } + /** + * Returns the width of the ellipse. + * @return The width of the ellipse. + */ public double getWidth() { return width; } + /** + * Returns x coordinate of the upper-left corner of + * the ellipse's bounding-box. + * @return The x coordinate. + */ public double getX() { return x; } + /** + * Returns y coordinate of the upper-left corner of + * the ellipse's bounding-box. + * @return The y coordinate. + */ public double getY() { return y; } + /** + * Returns <code>true</code> if the ellipse encloses no area, and + * <code>false</code> otherwise. + * + * @return A boolean. + */ public boolean isEmpty() { return height <= 0 || width <= 0; } + /** + * Sets the geometry of the ellipse's bounding box.<P> + * + * @param x - x coordinate of the upper-left of the bounding rectangle + * @param y - y coordinate of the upper-left of the bounding rectangle + * @param w - width of the ellipse + * @param h - height of the ellipse + */ public void setFrame(double x, double y, double w, double h) { this.x = x; @@ -136,17 +267,49 @@ public abstract class Ellipse2D extends RectangularShape } } // class Double + /** + * An {@link Ellipse2D} that stores its coordinates using <code>float</code> + * primitives. + */ public static class Float extends Ellipse2D { + /** + * The height of the ellipse. + */ public float height; + + /** + * The width of the ellipse. + */ public float width; + + /** + * The upper-left x coordinate of the bounding-box + */ public float x; + + /** + * The upper-left y coordinate of the bounding-box + */ public float y; + /** + * Creates a new Ellipse2D with an upper-left coordinate of (0,0) + * and a zero size. + */ public Float() { } + /** + * Creates a new Ellipse2D within a given rectangle + * using floating-point precision.<P> + * @param x - x coordinate of the upper-left of the bounding rectangle + * @param y - y coordinate of the upper-left of the bounding rectangle + * @param w - width of the ellipse + * @param h - height of the ellipse + * + */ public Float(float x, float y, float w, float h) { this.x = x; @@ -155,36 +318,72 @@ public abstract class Ellipse2D extends RectangularShape this.width = w; } + /** + * Returns the bounding-box of the ellipse. + * @return The bounding box. + */ public Rectangle2D getBounds2D() { return new Rectangle2D.Float(x, y, width, height); } + /** + * Returns the height of the ellipse. + * @return The height of the ellipse. + */ public double getHeight() { return height; } + /** + * Returns the width of the ellipse. + * @return The width of the ellipse. + */ public double getWidth() { return width; } + /** + * Returns x coordinate of the upper-left corner of + * the ellipse's bounding-box. + * @return The x coordinate. + */ public double getX() { return x; } + /** + * Returns y coordinate of the upper-left corner of + * the ellipse's bounding-box. + * @return The y coordinate. + */ public double getY() { return y; } + /** + * Returns <code>true</code> if the ellipse encloses no area, and + * <code>false</code> otherwise. + * + * @return A boolean. + */ public boolean isEmpty() { return height <= 0 || width <= 0; } + /** + * Sets the geometry of the ellipse's bounding box.<P> + * + * @param x - x coordinate of the upper-left of the bounding rectangle + * @param y - y coordinate of the upper-left of the bounding rectangle + * @param w - width of the ellipse + * @param h - height of the ellipse + */ public void setFrame(float x, float y, float w, float h) { this.x = x; @@ -193,6 +392,16 @@ public abstract class Ellipse2D extends RectangularShape width = w; } + /** + * Sets the geometry of the ellipse's bounding box. + * + * Note: This leads to a loss of precision.<P> + * + * @param x - x coordinate of the upper-left of the bounding rectangle + * @param y - y coordinate of the upper-left of the bounding rectangle + * @param w - width of the ellipse + * @param h - height of the ellipse + */ public void setFrame(double x, double y, double w, double h) { this.x = (float) x; |
