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TextHitInfo.java API Doc Java SE 5 API 8670 Fri Aug 26 14:56:50 BST 2005 java.awt.font

TextHitInfo

java.lang.Object

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 {@link 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: TextLayout

Fields Summary
private int
charIndex
private boolean
isLeadingEdge
Constructors Summary
private TextHitInfo(int charIndex, boolean isLeadingEdge)
Constructs a new TextHitInfo.
param
charIndex the index of the character hit
param
isLeadingEdge true if the leading edge of the character was hit
this.charIndex = charIndex; this.isLeadingEdge = isLeadingEdge;
Methods Summary
public static java.awt.font.TextHitInfo afterOffset(int offset)
Creates a 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 TextHitInfo at the specified offset.
return new TextHitInfo(offset, true);
public static java.awt.font.TextHitInfo beforeOffset(int offset)
Creates a 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 TextHitInfo at the specified offset.
return new TextHitInfo(offset-1, false);
public boolean equals(java.lang.Object obj)
Returns true if the specified Object is a TextHitInfo and equals this TextHitInfo.
param
obj the Object to test for equality
return
true if the specified Object equals this TextHitInfo; false otherwise.
return (obj instanceof TextHitInfo) && equals((TextHitInfo)obj);
public boolean equals(java.awt.font.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.
param
hitInfo a specified TextHitInfo
return
true if the specified TextHitInfo has the same charIndex and isLeadingEdge as this TextHitInfo.
return hitInfo != null && charIndex == hitInfo.charIndex && isLeadingEdge == hitInfo.isLeadingEdge;
public int getCharIndex()
Returns the index of the character hit.
return
the index of the character hit.
return charIndex;
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.
return
the insertion index.
return isLeadingEdge ? charIndex : charIndex + 1;
public java.awt.font.TextHitInfo getOffsetHit(int delta)
Creates a TextHitInfo whose character index is offset by delta from the charIndex of this TextHitInfo. This TextHitInfo remains unchanged.
param
delta the value to offset this charIndex
return
a TextHitInfo whose charIndex is offset by delta from the charIndex of this TextHitInfo.
return new TextHitInfo(charIndex + delta, isLeadingEdge);
public java.awt.font.TextHitInfo getOtherHit()
Creates a TextHitInfo on the other side of the insertion point. This TextHitInfo remains unchanged.
return
a TextHitInfo on the other side of the insertion point.
if (isLeadingEdge) { return trailing(charIndex - 1); } else { return leading(charIndex + 1); }
public int hashCode()
Returns the hash code.
return
the hash code of this TextHitInfo, which is also the charIndex of this TextHitInfo.
return charIndex;
public boolean isLeadingEdge()
Returns true if the leading edge of the character was hit.
return
true if the leading edge of the character was hit; false otherwise.
return isLeadingEdge;
public static java.awt.font.TextHitInfo leading(int charIndex)
Creates a TextHitInfo on the leading edge of the character at the specified charIndex.
param
charIndex the index of the character hit
return
a TextHitInfo on the leading edge of the character at the specified charIndex.
return new TextHitInfo(charIndex, true);
public java.lang.String toString()
Returns a String representing the hit for debugging use only.
return
a String representing this TextHitInfo.
return "TextHitInfo[" + charIndex + (isLeadingEdge ? "L" : "T")+"]";
public static java.awt.font.TextHitInfo trailing(int charIndex)
Creates a hit on the trailing edge of the character at the specified charIndex.
param
charIndex the index of the character hit
return
a TextHitInfo on the trailing edge of the character at the specified charIndex.
return new TextHitInfo(charIndex, false);