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/* * @(#)TextHitInfo.java 1.34 05/11/17 * * Copyright 2006 Sun Microsystems, Inc. All rights reserved. * SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms. */ /* * (C) Copyright Taligent, Inc. 1996 - 1997, All Rights Reserved * (C) Copyright IBM Corp. 1996 - 1998, All Rights Reserved * * The original version of this source code and documentation is * copyrighted and owned by Taligent, Inc., a wholly-owned subsidiary * of IBM. These materials are provided under terms of a License * Agreement between Taligent and Sun. This technology is protected * by multiple US and International patents. * * This notice and attribution to Taligent may not be removed. * Taligent is a registered trademark of Taligent, Inc. * */ package java.awt.font; import java.lang.String; /** * The <code>TextHitInfo</code> class represents a character position in a * text model, and a <b>bias</b>, or "side," of the character. Biases are * either <EM>leading</EM> (the left edge, for a left-to-right character) * or <EM>trailing</EM> (the right edge, for a left-to-right character). * Instances of <code>TextHitInfo</code> are used to specify caret and * insertion positions within text. * <p> * For example, consider the text "abc". TextHitInfo.trailing(1) * corresponds to the right side of the 'b' in the text. * <p> * <code>TextHitInfo</code> is used primarily by {@link TextLayout} and * clients of <code>TextLayout</code>. Clients of <code>TextLayout</code> * query <code>TextHitInfo</code> instances for an insertion offset, where * new text is inserted into the text model. The insertion offset is equal * to the character position in the <code>TextHitInfo</code> if the bias * is leading, and one character after if the bias is trailing. The * insertion offset for TextHitInfo.trailing(1) is 2. * <p> * Sometimes it is convenient to construct a <code>TextHitInfo</code> with * the same insertion offset as an existing one, but on the opposite * character. The <code>getOtherHit</code> method constructs a new * <code>TextHitInfo</code> with the same insertion offset as an existing * one, with a hit on the character on the other side of the insertion offset. * Calling <code>getOtherHit</code> on trailing(1) would return leading(2). * In general, <code>getOtherHit</code> for trailing(n) returns * leading(n+1) and <code>getOtherHit</code> for leading(n) * returns trailing(n-1). * <p> * <strong>Example</strong>:<p> * Converting a graphical point to an insertion point within a text * model * <blockquote><pre> * TextLayout layout = ...; * Point2D.Float hitPoint = ...; * TextHitInfo hitInfo = layout.hitTestChar(hitPoint.x, hitPoint.y); * int insPoint = hitInfo.getInsertionIndex(); * // insPoint is relative to layout; may need to adjust for use * // in a text model * </pre></blockquote> * * @see TextLayout */ public final class TextHitInfo { private int charIndex; private boolean isLeadingEdge; /** * Constructs a new <code>TextHitInfo</code>. * @param charIndex the index of the character hit * @param isLeadingEdge <code>true</code> if the leading edge of the * character was hit */ private TextHitInfo(int charIndex, boolean isLeadingEdge) { this.charIndex = charIndex; this.isLeadingEdge = isLeadingEdge; } /** * Returns the index of the character hit. * @return the index of the character hit. */ public int getCharIndex() { return charIndex; } /** * Returns <code>true</code> if the leading edge of the character was * hit. * @return <code>true</code> if the leading edge of the character was * hit; <code>false</code> otherwise. */ public boolean isLeadingEdge() { return isLeadingEdge; } /** * Returns the insertion index. This is the character index if * the leading edge of the character was hit, and one greater * than the character index if the trailing edge was hit. * @return the insertion index. */ public int getInsertionIndex() { return isLeadingEdge ? charIndex : charIndex + 1; } /** * Returns the hash code. * @return the hash code of this <code>TextHitInfo</code>, which is * also the <code>charIndex</code> of this <code>TextHitInfo</code>. */ public int hashCode() { return charIndex; } /** * Returns <code>true</code> if the specified <code>Object</code> is a * <code>TextHitInfo</code> and equals this <code>TextHitInfo</code>. * @param obj the <code>Object</code> to test for equality * @return <code>true</code> if the specified <code>Object</code> * equals this <code>TextHitInfo</code>; <code>false</code> otherwise. */ public boolean equals(Object obj) { return (obj instanceof TextHitInfo) && equals((TextHitInfo)obj); } /** * Returns <code>true</code> if the specified <code>TextHitInfo</code> * has the same <code>charIndex</code> and <code>isLeadingEdge</code> * as this <code>TextHitInfo</code>. This is not the same as having * the same insertion offset. * @param hitInfo a specified <code>TextHitInfo</code> * @return <code>true</code> if the specified <code>TextHitInfo</code> * has the same <code>charIndex</code> and <code>isLeadingEdge</code> * as this <code>TextHitInfo</code>. */ public boolean equals(TextHitInfo hitInfo) { return hitInfo != null && charIndex == hitInfo.charIndex && isLeadingEdge == hitInfo.isLeadingEdge; } /** * Returns a <code>String</code> representing the hit for debugging * use only. * @return a <code>String</code> representing this * <code>TextHitInfo</code>. */ public String toString() { return "TextHitInfo[" + charIndex + (isLeadingEdge ? "L" : "T")+"]"; } /** * Creates a <code>TextHitInfo</code> on the leading edge of the * character at the specified <code>charIndex</code>. * @param charIndex the index of the character hit * @return a <code>TextHitInfo</code> on the leading edge of the * character at the specified <code>charIndex</code>. */ public static TextHitInfo leading(int charIndex) { return new TextHitInfo(charIndex, true); } /** * Creates a hit on the trailing edge of the character at * the specified <code>charIndex</code>. * @param charIndex the index of the character hit * @return a <code>TextHitInfo</code> on the trailing edge of the * character at the specified <code>charIndex</code>. */ public static TextHitInfo trailing(int charIndex) { return new TextHitInfo(charIndex, false); } /** * Creates a <code>TextHitInfo</code> at the specified offset, * associated with the character before the offset. * @param offset an offset associated with the character before * the offset * @return a <code>TextHitInfo</code> at the specified offset. */ public static TextHitInfo beforeOffset(int offset) { return new TextHitInfo(offset-1, false); } /** * Creates a <code>TextHitInfo</code> at the specified offset, * associated with the character after the offset. * @param offset an offset associated with the character after * the offset * @return a <code>TextHitInfo</code> at the specified offset. */ public static TextHitInfo afterOffset(int offset) { return new TextHitInfo(offset, true); } /** * Creates a <code>TextHitInfo</code> on the other side of the * insertion point. This <code>TextHitInfo</code> remains unchanged. * @return a <code>TextHitInfo</code> on the other side of the * insertion point. */ public TextHitInfo getOtherHit() { if (isLeadingEdge) { return trailing(charIndex - 1); } else { return leading(charIndex + 1); } } /** * Creates a <code>TextHitInfo</code> whose character index is offset * by <code>delta</code> from the <code>charIndex</code> of this * <code>TextHitInfo</code>. This <code>TextHitInfo</code> remains * unchanged. * @param delta the value to offset this <code>charIndex</code> * @return a <code>TextHitInfo</code> whose <code>charIndex</code> is * offset by <code>delta</code> from the <code>charIndex</code> of * this <code>TextHitInfo</code>. */ public TextHitInfo getOffsetHit(int delta) { return new TextHitInfo(charIndex + delta, isLeadingEdge); } }