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Class TextHitInfo

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

Methods

getCharIndex

public int getCharIndex()

Returns the index of the character hit.

Returns:
the index of the character hit.

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.

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.

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.
See Also:
Object.equals(java.lang.Object), System.identityHashCode(java.lang.Object)

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.
See Also:
Object.hashCode(), HashMap

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.

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.

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.

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.

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.

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.

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.

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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Documentation extracted from Debian's OpenJDK Development Kit package.
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