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Java(TM) 2 Platform, Standard Edition, v1.2.2 API Specification: Class TextHitInfo - JDK 5 Documentation v1.2.2, Java 2 SDK 英文文档

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java.awt.font
Class TextHitInfo

java.lang.Object
  |
  +--java.awt.font.TextHitInfo

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public final class TextHitInfo

extends Object

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:

TextLayout

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Method Summary
static TextHitInfo	afterOffset(int offset)           Creates a TextHitInfo at the specified offset, associated with the character after the offset.
static TextHitInfo	beforeOffset(int offset)           Creates a TextHitInfo at the specified offset, associated with the character before the offset.
boolean	equals(Object obj)           Returns true if the specified Object is a TextHitInfo and equals this TextHitInfo.
boolean	equals(TextHitInfo hitInfo)           Returns true if the specified TextHitInfo has the same charIndex and isLeadingEdge as this TextHitInfo.
int	getCharIndex()           Returns the index of the character hit.
int	getInsertionIndex()           Returns the insertion index.
TextHitInfo	getOffsetHit(int delta)           Creates a TextHitInfo whose character index is offset by delta from the charIndex of this TextHitInfo.
TextHitInfo	getOtherHit()           Creates a TextHitInfo on the other side of the insertion point.
int	hashCode()           Returns the hash code.
boolean	isLeadingEdge()           Returns true if the leading edge of the character was hit.
static TextHitInfo	leading(int charIndex)           Creates a TextHitInfo on the leading edge of the character at the specified charIndex.
String	toString()           Returns a String representing the hit for debugging use only.
static TextHitInfo	trailing(int charIndex)           Creates a hit on the trailing edge of the character at the specified charIndex.

 

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

 

Method Detail

getCharIndex

public int getCharIndex()

Returns the index of the character hit.

Returns:

the index of the character hit.

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isLeadingEdge

public boolean isLeadingEdge()

Returns true if the leading edge of the character was hit.

Returns:

true if the leading edge of the character was hit; false otherwise.

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getInsertionIndex

public int getInsertionIndex()

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.

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hashCode

public int hashCode()

Returns the hash code.

Overrides:

hashCode in class Object

Returns:

the hash code of this TextHitInfo, which is also the charIndex of this TextHitInfo.

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equals

public boolean equals(Object obj)

Returns true if the specified Object is a TextHitInfo and equals this TextHitInfo.

Overrides:

equals in class Object

Parameters:

obj - the Object to test for equality

Returns:

true if the specified Object equals this TextHitInfo; false otherwise.

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equals

public boolean equals(TextHitInfo hitInfo)

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.

Parameters:

hitInfo - a specified TextHitInfo

Returns:

true if the specified TextHitInfo has the same charIndex and isLeadingEdge as this TextHitInfo.

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toString

public String toString()

Returns a String representing the hit for debugging use only.

Overrides:

toString in class Object

Returns:

a String representing this TextHitInfo.

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leading

public static TextHitInfo leading(int charIndex)

Creates a TextHitInfo on the leading edge of the character at the specified charIndex.

Parameters:

charIndex - the index of the character hit

Returns:

a TextHitInfo on the leading edge of the character at the specified charIndex.

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trailing

public static TextHitInfo trailing(int charIndex)

Creates a hit on the trailing edge of the character at the specified charIndex.

Parameters:

charIndex - the index of the character hit

Returns:

a TextHitInfo on the trailing edge of the character at the specified charIndex.

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beforeOffset

public static TextHitInfo beforeOffset(int offset)

Creates a TextHitInfo at the specified offset, associated with the character before the offset.

Parameters:

offset - an offset associated with the character before the offset

Returns:

a TextHitInfo at the specified offset.

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afterOffset

public static TextHitInfo afterOffset(int offset)

Creates a TextHitInfo at the specified offset, associated with the character after the offset.

Parameters:

offset - an offset associated with the character after the offset

Returns:

a TextHitInfo at the specified offset.

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getOtherHit

public TextHitInfo getOtherHit()

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.

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getOffsetHit

public TextHitInfo getOffsetHit(int delta)

Creates a TextHitInfo whose character index is offset by delta from the charIndex of this TextHitInfo. This TextHitInfo remains unchanged.

Parameters:

delta - the value to offset this charIndex

Returns:

a TextHitInfo whose charIndex is offset by delta from the charIndex of this TextHitInfo.

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