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/*
 * (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 TextHitInfo class represents a character position in a text model, and a bias, or "side," of the character.  Biases are
either leading (the left edge, for a left-to-right character)
or trailing (the right edge, for a left-to-right character). Instances of TextHitInfo are used to specify caret and insertion positions within text. 

For example, consider the text "abc".  TextHitInfo.trailing(1)
corresponds to the right side of the 'b' in the text.

 TextHitInfo is used primarily by TextLayout and clients of TextLayout. Clients of TextLayout query TextHitInfo 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 TextHitInfo if the bias is leading, and one character after if the bias is trailing. The insertion offset for TextHitInfo.trailing(1) is 2. 
 Sometimes it is convenient to construct a TextHitInfo with the same insertion offset as an existing one, but on the opposite character. The getOtherHit method constructs a new TextHitInfo with the same insertion offset as an existing one, with a hit on the character on the other side of the insertion offset. Calling getOtherHit on trailing(1) would return leading(2). In general, getOtherHit for trailing(n) returns leading(n+1) and getOtherHit for leading(n) returns trailing(n-1). 

Example:

Converting a graphical point to an insertion point within a text
model

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



See Also:
/**
 * The {@code TextHitInfo} 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} 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} is used primarily by {@link TextLayout} and
 * clients of {@code TextLayout}.  Clients of {@code TextLayout}
 * query {@code TextHitInfo} 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} 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} with
 * the same insertion offset as an existing one, but on the opposite
 * character.  The {@code getOtherHit} method constructs a new
 * {@code TextHitInfo} 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} on trailing(1) would return leading(2).
 * In general, {@code getOtherHit} for trailing(n) returns
 * leading(n+1) and {@code getOtherHit} 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 TextHitInfo. 
Params:
  • charIndex – the index of the character hit
  • isLeadingEdge – true if the leading edge of the character was hit
/**
     * Constructs a new {@code TextHitInfo}.
     * @param charIndex the index of the character hit
     * @param isLeadingEdge {@code true} 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.

Returns:the index of the character hit.
/**
     * Returns the index of the character hit.
     * @return the index of the character hit.
     */
    public int getCharIndex() {
        return charIndex;
    }

    
Returns true if the leading edge of the character was hit. 
Returns:true if the leading edge of the character was hit; false otherwise.
/**
     * Returns {@code true} if the leading edge of the character was
     * hit.
     * @return {@code true} if the leading edge of the character was
     * hit; {@code false} 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.

Returns:the insertion index.
/**
     * 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.

Returns:the hash code of this TextHitInfo, which is also the charIndex of this TextHitInfo.
/**
     * Returns the hash code.
     * @return the hash code of this {@code TextHitInfo}, which is
     * also the {@code charIndex} of this {@code TextHitInfo}.
     */
    public int hashCode() {
        return charIndex;
    }

    
Returns true if the specified Object is a TextHitInfo and equals this TextHitInfo. 
Params:
  • obj – the Object to test for equality
Returns:true if the specified Object equals this TextHitInfo; false otherwise.
/**
     * Returns {@code true} if the specified {@code Object} is a
     * {@code TextHitInfo} and equals this {@code TextHitInfo}.
     * @param obj the {@code Object} to test for equality
     * @return {@code true} if the specified {@code Object}
     * equals this {@code TextHitInfo}; {@code false} otherwise.
     */
    public boolean equals(Object obj) {
        return (obj instanceof TextHitInfo) && equals((TextHitInfo)obj);
    }

    
Returns true if the specified TextHitInfo has the same charIndex and isLeadingEdge as this TextHitInfo. This is not the same as having the same insertion offset. 
Params:
  • hitInfo – a specified TextHitInfo
Returns:true if the specified TextHitInfo has the same charIndex and isLeadingEdge as this TextHitInfo.
/**
     * Returns {@code true} if the specified {@code TextHitInfo}
     * has the same {@code charIndex} and {@code isLeadingEdge}
     * as this {@code TextHitInfo}.  This is not the same as having
     * the same insertion offset.
     * @param hitInfo a specified {@code TextHitInfo}
     * @return {@code true} if the specified {@code TextHitInfo}
     * has the same {@code charIndex} and {@code isLeadingEdge}
     * as this {@code TextHitInfo}.
     */
    public boolean equals(TextHitInfo hitInfo) {
        return hitInfo != null && charIndex == hitInfo.charIndex &&
            isLeadingEdge == hitInfo.isLeadingEdge;
    }

    
Returns a String representing the hit for debugging use only. 
Returns:a String representing this TextHitInfo.
/**
     * Returns a {@code String} representing the hit for debugging
     * use only.
     * @return a {@code String} representing this
     * {@code TextHitInfo}.
     */
    public String toString() {
        return "TextHitInfo[" + charIndex + (isLeadingEdge ? "L" : "T")+"]";
    }

    
Creates a TextHitInfo on the leading edge of the character at the specified charIndex. 
Params:
  • charIndex – the index of the character hit
Returns:a TextHitInfo on the leading edge of the character at the specified charIndex.
/**
     * Creates a {@code TextHitInfo} on the leading edge of the
     * character at the specified {@code charIndex}.
     * @param charIndex the index of the character hit
     * @return a {@code TextHitInfo} on the leading edge of the
     * character at the specified {@code charIndex}.
     */
    public static TextHitInfo leading(int charIndex) {
        return new TextHitInfo(charIndex, true);
    }

    
Creates a hit on the trailing edge of the character at the specified charIndex. 
Params:
  • charIndex – the index of the character hit
Returns:a TextHitInfo on the trailing edge of the character at the specified charIndex.
/**
     * Creates a hit on the trailing edge of the character at
     * the specified {@code charIndex}.
     * @param charIndex the index of the character hit
     * @return a {@code TextHitInfo} on the trailing edge of the
     * character at the specified {@code charIndex}.
     */
    public static TextHitInfo trailing(int charIndex) {
        return new TextHitInfo(charIndex, false);
    }

    
Creates a TextHitInfo at the specified offset, associated with the character before the offset. 
Params:
  • offset – an offset associated with the character before
the offset
Returns:a TextHitInfo at the specified offset.
/**
     * Creates a {@code TextHitInfo} 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} at the specified offset.
     */
    public static TextHitInfo beforeOffset(int offset) {
        return new TextHitInfo(offset-1, false);
    }

    
Creates a TextHitInfo at the specified offset, associated with the character after the offset. 
Params:
  • offset – an offset associated with the character after
the offset
Returns:a TextHitInfo at the specified offset.
/**
     * Creates a {@code TextHitInfo} 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} at the specified offset.
     */
    public static TextHitInfo afterOffset(int offset) {
        return new TextHitInfo(offset, true);
    }

    
Creates a TextHitInfo on the other side of the insertion point. This TextHitInfo remains unchanged. 
Returns:a TextHitInfo on the other side of the insertion point.
/**
     * Creates a {@code TextHitInfo} on the other side of the
     * insertion point.  This {@code TextHitInfo} remains unchanged.
     * @return a {@code TextHitInfo} on the other side of the
     * insertion point.
     */
    public TextHitInfo getOtherHit() {
        if (isLeadingEdge) {
            return trailing(charIndex - 1);
        } else {
            return leading(charIndex + 1);
        }
    }

    
Creates a TextHitInfo whose character index is offset by delta from the charIndex of this TextHitInfo. This TextHitInfo remains unchanged. 
Params:
  • delta – the value to offset this charIndex
Returns:a TextHitInfo whose charIndex is offset by delta from the charIndex of this TextHitInfo.
/**
     * Creates a {@code TextHitInfo} whose character index is offset
     * by {@code delta} from the {@code charIndex} of this
     * {@code TextHitInfo}. This {@code TextHitInfo} remains
     * unchanged.
     * @param delta the value to offset this {@code charIndex}
     * @return a {@code TextHitInfo} whose {@code charIndex} is
     * offset by {@code delta} from the {@code charIndex} of
     * this {@code TextHitInfo}.
     */
    public TextHitInfo getOffsetHit(int delta) {
        return new TextHitInfo(charIndex + delta, isLeadingEdge);
    }
}