Insets.java

/*******************************************************************************
 * Copyright (c) 2000, 2005 IBM Corporation and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
package org.eclipse.draw2d.geometry;

/**
 * Stores four integers for top, left, bottom, and right measurements.
 */
public class Insets
	implements Cloneable, java.io.Serializable
{

/** distance from left  */
public int left;
/** distance from top*/
public int top;
/** distance from bottom*/
public int bottom;
/** distance from right */
public int right;

static final long serialVersionUID = 1;

/**
 * Constructs an Insets with all zeroes.
 * @since 2.0
 */
public Insets() { }

/**
 * Constructs a new Insets with initial values the same as the provided Insets.
 * @param i  The insets to copy.
 * @since 2.0
 */
public Insets(Insets i) {
	this(i.top, i.left, i.bottom, i.right);
}

/**
 * Constructs a new Insets with all the sides set to the speicifed value.
 * @param i  Value applied to all sides of new Insets.
 * @since 2.0
 */
public Insets(int i) {
	this(i, i, i, i);
}

/**
 * Creates a new Insets with the specified top, left, bottom, and right values.
 * @param top  Value of the top space.
 * @param left  Value of the left space.
 * @param bottom  Value of the bottom space.
 * @param right  Value of the right space.
 * @since 2.0
 */
public Insets(int top, int left, int bottom, int right) {
	this.top = top;
	this.left = left;
	this.bottom = bottom;
	this.right = right;
}

/**
 * Adds the values of the specified Insets to this Insets' values.
 * @return <code>this</code> for convenience
 * @param insets the Insets being added
 * @since 2.0
 */
public Insets add(Insets insets) {
	top    += insets.top;
	bottom += insets.bottom;
	left   += insets.left;
	right  += insets.right;
	return this;
}

/**
 * Test for equality.
 * The Insets are equal if their top, left, bottom, and 
 * right values are equivalent.
 *
 * @param o  Object being tested for equality.
 * @return  true if all values are the same.
 * @since 2.0
 */
public boolean equals(Object o) {
	if (o instanceof Insets) {
		Insets i = (Insets)o;
		return i.top == top
			&& i.bottom == bottom
			&& i.left == left
			&& i.right == right;
	}
	return false;
}

/**
 * Creates an Insets representing the sum of this Insets with the specified Insets.
 * @param insets  Insets to be added
 * @return  A new Insets
 * @since 2.0
 */
public Insets getAdded(Insets insets) {
	return new Insets(this).add(insets);
}

/**
 * Returns the height for this Insets, equal to <code>top</code> + <code>bottom</code>.
 * @return The sum of top + bottom
 * @see  #getWidth()
 * @since 2.0
 */
public int getHeight() {
	return top + bottom;
}

/**
 * Creates a new Insets with transposed values.
 * Top and Left are transposed.
 * Bottom and Right are transposed.
 * @return  New Insets with the transposed values.
 * @since 2.0
 */
public Insets getTransposed() {
	return new Insets(this).transpose();
}

/**
 * Returns the width for this Insets, equal to <code>left</code> + <code>right</code>.
 * @return The sum of left + right
 * @see  #getHeight()
 * @since 2.0
 */
public int getWidth() {
	return left + right;
}

/**
 * @see java.lang.Object#hashCode()
 */
public int hashCode() {
	return top * 7 + left * 2 + bottom * 31 + right * 37;
}


/**
 * Returns true if all values are 0.
 * @return true if all values are 0
 * @since 2.0
 */
public boolean isEmpty() {
	return (left == 0 && right == 0 && top == 0 && bottom == 0);
}

/**
 * @return String representation.
 * @since 2.0
 */
public String toString() {
	return "Insets(t=" + top + ", l=" + left + //$NON-NLS-2$//$NON-NLS-1$
		 ", b=" + bottom + ", r=" + right + ")";//$NON-NLS-3$//$NON-NLS-2$//$NON-NLS-1$
}

/**
 * Transposes this object.  Top and Left are exchanged.  Bottom and Right are exchanged.
 * Can be used in orientation changes.
 * @return <code>this</code> for convenience
 * @since 2.0
 */
public Insets transpose() {
	int temp = top;
	top = left;
	left = temp;
	temp = right;
	right = bottom;
	bottom = temp;
	return this;
}

}