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

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java.awt.font
Class TextLayout

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

public final class TextLayout
extends Object
implements Cloneable

TextLayout is an immutable graphical representation of styled character data.

It provides the following capabilities:

implicit bidirectional analysis and reordering,
cursor positioning and movement, including split cursors for mixed directional text,
highlighting, including both logical and visual highlighting for mixed directional text,
multiple baselines (roman, hanging, and centered),
hit testing,
justification,
default font substitution,
metric information such as ascent, descent, and advance, and
rendering

A TextLayout object can be rendered using its draw method.

TextLayout can be constructed either directly or through the use of a LineBreakMeasurer. When constructed directly, the source text represents a single paragraph. LineBreakMeasurer allows styled text to be broken into lines that fit within a particular width. See the LineBreakMeasurer documentation for more information.

TextLayout construction logically proceeds as follows:

paragraph attributes are extracted and examined,
text is analyzed for bidirectional reordering, and reordering information is computed if needed,
text is segmented into style runs
fonts are chosen for style runs, first by using a font if the attribute TextAttribute.FONT is present, otherwise by computing a default font using the attributes that have been defined
if text is on multiple baselines, the runs or subruns are further broken into subruns sharing a common baseline,
glyphvectors are generated for each run using the chosen font,
final bidirectional reordering is performed on the glyphvectors

All graphical information returned from a TextLayout object's methods is relative to the origin of the TextLayout, which is the intersection of the TextLayout object's baseline with its left edge. Also, coordinates passed into a TextLayout object's methods are assumed to be relative to the TextLayout object's origin. Clients usually need to translate between a TextLayout object's coordinate system and the coordinate system in another object (such as a Graphics object).

TextLayout objects are constructed from styled text, but they do not retain a reference to their source text. Thus, changes in the text previously used to generate a TextLayout do not affect the TextLayout.

Three methods on a TextLayout object (getNextRightHit, getNextLeftHit, and hitTestChar) return instances of TextHitInfo. The offsets contained in these TextHitInfo objects are relative to the start of the TextLayout, not to the text used to create the TextLayout. Similarly, TextLayout methods that accept TextHitInfo instances as parameters expect the TextHitInfo object's offsets to be relative to the TextLayout, not to any underlying text storage model.

Examples:

Constructing and drawing a TextLayout and its bounding rectangle:

   Graphics2D g = ...;
   Point2D loc = ...;
   Font font = Font.getFont("Helvetica-bold-italic");
   FontRenderContext frc = g.getFontRenderContext();
   TextLayout layout = new TextLayout("This is a string", font, frc);
   layout.draw(g, loc.getX(), loc.getY());

   Rectangle2D bounds = layout.getBounds();
   bounds.setRect(bounds.getX()+loc.getX(),
                  bounds.getY()+loc.getY(),
                  bounds.getWidth(),
                  bounds.getHeight())
   g.draw(bounds);

Hit-testing a TextLayout (determining which character is at a particular graphical location):

   Point2D click = ...;
   TextHitInfo hit = layout.hitTestChar(
                         (float) (click.getX() - loc.getX()),
                         (float) (click.getY() - loc.getY()));

Responding to a right-arrow key press:

   int insertionIndex = ...;
   TextHitInfo next = layout.getNextRightHit(insertionIndex);
   if (next != null) {
       // translate graphics to origin of layout on screen
       g.translate(loc.getX(), loc.getY());
       Shape[] carets = layout.getCaretShapes(next.getInsertionIndex());
       g.draw(carets[0]);
       if (carets[1] != null) {
           g.draw(carets[1]);
       }
   }

Drawing a selection range corresponding to a substring in the source text. The selected area may not be visually contiguous:

   // selStart, selLimit should be relative to the layout,
   // not to the source text

   int selStart = ..., selLimit = ...;
   Color selectionColor = ...;
   Shape selection = layout.getLogicalHighlightShape(selStart, selLimit);
   // selection may consist of disjoint areas
   // graphics is assumed to be tranlated to origin of layout
   g.setColor(selectionColor);
   g.fill(selection);

Drawing a visually contiguous selection range. The selection range may correspond to more than one substring in the source text. The ranges of the corresponding source text substrings can be obtained with getLogicalRangesForVisualSelection():

   TextHitInfo selStart = ..., selLimit = ...;
   Shape selection = layout.getVisualHighlightShape(selStart, selLimit);
   g.setColor(selectionColor);
   g.fill(selection);
   int[] ranges = getLogicalRangesForVisualSelection(selStart, selLimit);
   // ranges[0], ranges[1] is the first selection range,
   // ranges[2], ranges[3] is the second selection range, etc.

See Also:: LineBreakMeasurer, TextAttribute, TextHitInfo

Inner Class Summary

static class TextLayout.CaretPolicy
          Defines a policy for determining the strong caret location.

Field Summary

static TextLayout.CaretPolicy DEFAULT_CARET_POLICY
          This CaretPolicy is used when a policy is not specified by the client.

Constructor Summary

TextLayout(AttributedCharacterIterator text, FontRenderContext frc)
          Constructs a TextLayout from an iterator over styled text.

TextLayout(String string, Font font, FontRenderContext frc)
          Constructs a TextLayout from a String and a Font.

TextLayout(String string, Map attributes, FontRenderContext frc)
          Constructs a TextLayout from a String and an attribute set.

Method Summary

protected Object clone()
          Creates a copy of this TextLayout.

void draw(Graphics2D g2, float x, float y)
          Renders this TextLayout at the specified location in the specified Graphics2D context.

boolean equals(Object obj)
          Returns true if the specified Object is a TextLayout object and if the specified Object equals this TextLayout.

boolean equals(TextLayout rhs)
          Returns true if the two layouts are equal.

float getAdvance()
          Returns the advance of this TextLayout.

float getAscent()
          Returns the ascent of this TextLayout.

byte getBaseline()
          Returns the baseline for this TextLayout.

float[] getBaselineOffsets()
          Returns the offsets array for the baselines used for this TextLayout.

Shape getBlackBoxBounds(int firstEndpoint, int secondEndpoint)
          Returns the black box bounds of the characters in the specified range.

Rectangle2D getBounds()
          Returns the bounds of this TextLayout.

float[] getCaretInfo(TextHitInfo hit)
          Returns information about the caret corresponding to hit.

float[] getCaretInfo(TextHitInfo hit, Rectangle2D bounds)
          Returns information about the caret corresponding to hit.

Shape getCaretShape(TextHitInfo hit)
          Returns a Shape representing the caret at the specified hit inside the natural bounds of this TextLayout.

Shape getCaretShape(TextHitInfo hit, Rectangle2D bounds)
          Returns a Shape representing the caret at the specified hit inside the specified bounds.

Shape[] getCaretShapes(int offset)
          Returns two paths corresponding to the strong and weak caret.

Shape[] getCaretShapes(int offset, Rectangle2D bounds)
          Returns two paths corresponding to the strong and weak caret.

Shape[] getCaretShapes(int offset, Rectangle2D bounds, TextLayout.CaretPolicy policy)
          Returns two paths corresponding to the strong and weak caret.

int getCharacterCount()
          Returns the number of characters represented by this TextLayout.

byte getCharacterLevel(int index)
          Returns the level of the character at index.

float getDescent()
          Returns the descent of this TextLayout.

TextLayout getJustifiedLayout(float justificationWidth)
          Creates a copy of this TextLayout justified to the specified width.

float getLeading()
          Returns the leading of the TextLayout.

Shape getLogicalHighlightShape(int firstEndpoint, int secondEndpoint)
          Returns a Shape enclosing the logical selection in the specified range, extended to the natural bounds of this TextLayout.

Shape getLogicalHighlightShape(int firstEndpoint, int secondEndpoint, Rectangle2D bounds)
          Returns a Shape enclosing the logical selection in the specified range, extended to the specified bounds.

int[] getLogicalRangesForVisualSelection(TextHitInfo firstEndpoint, TextHitInfo secondEndpoint)
          Returns the logical ranges of text corresponding to a visual selection.

TextHitInfo getNextLeftHit(int offset)
          Returns the hit for the next caret to the left (top); if no such hit, returns null.

TextHitInfo getNextLeftHit(int offset, TextLayout.CaretPolicy policy)
          Returns the hit for the next caret to the left (top); if no such hit, returns null.

TextHitInfo getNextLeftHit(TextHitInfo hit)
          Returns the hit for the next caret to the left (top); if no such hit, returns null.

TextHitInfo getNextRightHit(int offset)
          Returns the hit for the next caret to the right (bottom); if no such hit, returns null.

TextHitInfo getNextRightHit(int offset, TextLayout.CaretPolicy policy)
          Returns the hit for the next caret to the right (bottom); if no such hit, returns null.

TextHitInfo getNextRightHit(TextHitInfo hit)
          Returns the hit for the next caret to the right (bottom); if there is no such hit, returns null.

Shape getOutline(AffineTransform tx)
          Returns a Shape representing the outline of this TextLayout.

float getVisibleAdvance()
          Returns the advance of this TextLayout, minus trailing whitespace.

Shape getVisualHighlightShape(TextHitInfo firstEndpoint, TextHitInfo secondEndpoint)
          Returns a Shape enclosing the visual selection in the specified range, extended to the bounds.

Shape getVisualHighlightShape(TextHitInfo firstEndpoint, TextHitInfo secondEndpoint, Rectangle2D bounds)
          Returns a path enclosing the visual selection in the specified range, extended to bounds.

TextHitInfo getVisualOtherHit(TextHitInfo hit)
          Returns the hit on the opposite side of the specified hit's caret.

protected void handleJustify(float justificationWidth)
          Justify this layout.

int hashCode()
          Returns the hash code of this TextLayout.

TextHitInfo hitTestChar(float x, float y)
          Returns a TextHitInfo corresponding to the specified point.

TextHitInfo hitTestChar(float x, float y, Rectangle2D bounds)
          Returns a TextHitInfo corresponding to the specified point.

boolean isLeftToRight()
          Returns true if this TextLayout has a left-to-right base direction or false if it has a right-to-left base direction.

boolean isVertical()
          Returns true if this TextLayout is vertical.

String toString()
          Returns debugging information for this TextLayout.

Methods inherited from class java.lang.Object

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

Field Detail

DEFAULT_CARET_POLICY

public static final TextLayout.CaretPolicy DEFAULT_CARET_POLICY

This CaretPolicy is used when a policy is not specified by the client. With this policy, a hit on a character whose direction is the same as the line direction is stronger than a hit on a counterdirectional character. If the characters' directions are the same, a hit on the leading edge of a character is stronger than a hit on the trailing edge of a character.

Constructor Detail

TextLayout

public TextLayout(String string,
                  Font font,
                  FontRenderContext frc)

Constructs a TextLayout from a String and a Font. All the text is styled using the specified Font.

The String must specify a single paragraph of text, because an entire paragraph is required for the bidirectional algorithm.

Parameters:: str - the text to display; font - a Font used to style the text; frc - contains the information needed to correctly measure the text

TextLayout

public TextLayout(String string,
                  Map attributes,
                  FontRenderContext frc)

Constructs a TextLayout from a String and an attribute set.

All the text is styled using the provided attributes.

string must specify a single paragraph of text because an entire paragraph is required for the bidirectional algorithm.

Parameters:: str - the text to display; attributes - the attributes used to style the text; frc - contains the information needed to correctly measure the text

TextLayout

public TextLayout(AttributedCharacterIterator text,
                  FontRenderContext frc)

Constructs a TextLayout from an iterator over styled text.

The iterator must specify a single paragraph of text because an entire paragraph is required for the bidirectional algorithm.

Parameters:: text - the styled text to display; frc - contains the information needed to correctly measure the text

Method Detail

clone

protected Object clone()

Creates a copy of this TextLayout.

Overrides:: clone in class Object

Tags copied from class: Object

Returns:: a clone of this instance.
Throws:: CloneNotSupportedException - if the object's class does not support the Cloneable interface. Subclasses that override the clone method can also throw this exception to indicate that an instance cannot be cloned.; OutOfMemoryError - if there is not enough memory.
See Also:: Cloneable

getJustifiedLayout

public TextLayout getJustifiedLayout(float justificationWidth)

Creates a copy of this TextLayout justified to the specified width.

If this TextLayout has already been justified, an exception is thrown. If this TextLayout object's justification ratio is zero, a TextLayout identical to this TextLayout is returned.

Parameters:: justificationWidth - the width to use when justifying the line. For best results, it should not be too different from the current advance of the line.
Returns:: a TextLayout justified to the specified width.
Throws:: Error - if this layout has already been justified, an Error is thrown.

handleJustify

protected void handleJustify(float justificationWidth)

Justify this layout. Overridden by subclassers to control justification (if there were subclassers, that is...) The layout will only justify if the paragraph attributes (from the source text, possibly defaulted by the layout attributes) indicate a non-zero justification ratio. The text will be justified to the indicated width. The current implementation also adjusts hanging punctuation and trailing whitespace to overhang the justification width. Once justified, the layout may not be rejustified.

Some code may rely on immutablity of layouts. Subclassers should not call this directly, but instead should call getJustifiedLayout, which will call this method on a clone of this layout, preserving the original.

Parameters:: justificationWidth - the width to use when justifying the line. For best results, it should not be too different from the current advance of the line.
See Also:: getJustifiedLayout(float)

getBaseline

public byte getBaseline()

Returns the baseline for this TextLayout. The baseline is one of the values defined in Font, which are roman, centered and hanging. Ascent and descent are relative to this baseline. The baselineOffsets are also relative to this baseline.

Returns:: the baseline of this TextLayout.
See Also:: getBaselineOffsets(), Font

getBaselineOffsets

public float[] getBaselineOffsets()

Returns the offsets array for the baselines used for this TextLayout.

The array is indexed by one of the values defined in Font, which are roman, centered and hanging. The values are relative to this TextLayout object's baseline, so that getBaselineOffsets[getBaseline()] == 0. Offsets are added to the position of the TextLayout object's baseline to get the position for the new baseline.

Returns:: the offsets array containing the baselines used for this TextLayout.
See Also:: getBaseline(), Font

getAdvance

public float getAdvance()

Returns the advance of this TextLayout. The advance is the distance from the origin to the advance of the rightmost (bottommost) character measuring in the line direction.

Returns:: the advance of this TextLayout.

getVisibleAdvance

public float getVisibleAdvance()

Returns the advance of this TextLayout, minus trailing whitespace.

Returns:: the advance of this TextLayout without the trailing whitespace.
See Also:: getAdvance()

getAscent

public float getAscent()

Returns the ascent of this TextLayout. The ascent is the distance from the top (right) of the TextLayout to the baseline. It is always either positive or zero. The ascent is sufficient to accomodate superscripted text and is the maximum of the sum of the ascent, offset, and baseline of each glyph.

Returns:: the ascent of this TextLayout.

getDescent

public float getDescent()

Returns the descent of this TextLayout. The descent is the distance from the baseline to the bottom (left) of the TextLayout. It is always either positive or zero. The descent is sufficient to accomodate subscripted text and is the maximum of the sum of the descent, offset, and baseline of each glyph.

Returns:: the descent of this TextLayout.

getLeading

public float getLeading()

Returns the leading of the TextLayout. The leading is the suggested interline spacing for this TextLayout.

The leading is computed from the leading, descent, and baseline of all glyphvectors in the TextLayout. The algorithm is roughly as follows:

 maxD = 0;
 maxDL = 0;
 for (GlyphVector g in all glyphvectors) {
    maxD = max(maxD, g.getDescent() + offsets[g.getBaseline()]);
    maxDL = max(maxDL, g.getDescent() + g.getLeading() +
                       offsets[g.getBaseline()]);
 }
 return maxDL - maxD;

Returns:: the leading of this TextLayout.

getBounds

public Rectangle2D getBounds()

Returns the bounds of this TextLayout. The bounds contains all of the pixels the TextLayout can draw. It might not coincide exactly with the ascent, descent, origin or advance of the TextLayout.

Returns:: a Rectangle2D that is the bounds of this TextLayout.

isLeftToRight

public boolean isLeftToRight()

Returns true if this TextLayout has a left-to-right base direction or false if it has a right-to-left base direction. The TextLayout has a base direction of either left-to-right (LTR) or right-to-left (RTL). The base direction is independent of the actual direction of text on the line, which may be either LTR, RTL, or mixed. Left-to-right layouts by default should position flush left. If the layout is on a tabbed line, the tabs run left to right, so that logically successive layouts position left to right. The opposite is true for RTL layouts. By default they should position flush left, and tabs run right-to-left.

Returns:: true if the base direction of this TextLayout is left-to-right; false otherwise.

isVertical

public boolean isVertical()

Returns true if this TextLayout is vertical.

Returns:: true if this TextLayout is vertical; false otherwise.

getCharacterCount

public int getCharacterCount()

Returns the number of characters represented by this TextLayout.

Returns:: the number of characters in this TextLayout.

getCaretInfo

public float[] getCaretInfo(TextHitInfo hit,
                            Rectangle2D bounds)

Returns information about the caret corresponding to hit. The first element of the array is the intersection of the caret with the baseline. The second element of the array is the slope (run/rise) of the caret.

This method is meant for informational use. To display carets, it is better to use getCaretShapes.

Parameters:: hit - a hit on a character in this TextLayout; bounds - the bounds to which the caret info is constructed
Returns:: a two-element array containing the position and slope of the caret.
See Also:: getCaretShapes(int, Rectangle2D, TextLayout.CaretPolicy)

getCaretInfo

public float[] getCaretInfo(TextHitInfo hit)

Returns information about the caret corresponding to hit. This method is a convenience overload of getCaretInfo and uses the natural bounds of this TextLayout.

Parameters:: hit - a hit on a character in this TextLayout
Returns:: the information about a caret corresponding to a hit.

getNextRightHit

public TextHitInfo getNextRightHit(TextHitInfo hit)

Returns the hit for the next caret to the right (bottom); if there is no such hit, returns null. If the hit character index is out of bounds, an IllegalArgumentException is thrown.

Parameters:: hit - a hit on a character in this layout
Returns:: a hit whose caret appears at the next position to the right (bottom) of the caret of the provided hit or null.

getNextRightHit

public TextHitInfo getNextRightHit(int offset,
                                   TextLayout.CaretPolicy policy)

Returns the hit for the next caret to the right (bottom); if no such hit, returns null. The hit is to the right of the strong caret at the specified offset, as determined by the specified policy. The returned hit is the stronger of the two possible hits, as determined by the specified policy.

Parameters:: offset - an insertion offset in this TextLayout. Cannot be less than 0 or greater than this TextLayout object's character count.; policy - the policy used to select the strong caret
Returns:: a hit whose caret appears at the next position to the right (bottom) of the caret of the provided hit, or null.

getNextRightHit

public TextHitInfo getNextRightHit(int offset)

Returns the hit for the next caret to the right (bottom); if no such hit, returns null. The hit is to the right of the strong caret at the specified offset, as determined by the default policy. The returned hit is the stronger of the two possible hits, as determined by the default policy.

Parameters:: offset - an insertion offset in this TextLayout. Cannot be less than 0 or greater than the TextLayout object's character count.
Returns:: a hit whose caret appears at the next position to the right (bottom) of the caret of the provided hit, or null.

getNextLeftHit

public TextHitInfo getNextLeftHit(TextHitInfo hit)

Returns the hit for the next caret to the left (top); if no such hit, returns null. If the hit character index is out of bounds, an IllegalArgumentException is thrown.

Parameters:: hit - a hit on a character in this TextLayout.
Returns:: a hit whose caret appears at the next position to the left (top) of the caret of the provided hit, or null.

getNextLeftHit

public TextHitInfo getNextLeftHit(int offset,
                                  TextLayout.CaretPolicy policy)

Returns the hit for the next caret to the left (top); if no such hit, returns null. The hit is to the left of the strong caret at the specified offset, as determined by the specified policy. The returned hit is the stronger of the two possible hits, as determined by the specified policy.

Parameters:: offset - an insertion offset in this TextLayout. Cannot be less than 0 or greater than this TextLayout object's character count.; policy - the policy used to select the strong caret
Returns:: a hit whose caret appears at the next position to the left (top) of the caret of the provided hit, or null.

getNextLeftHit

public TextHitInfo getNextLeftHit(int offset)

Returns the hit for the next caret to the left (top); if no such hit, returns null. The hit is to the left of the strong caret at the specified offset, as determined by the default policy. The returned hit is the stronger of the two possible hits, as determined by the default policy.

Parameters:: offset - an insertion offset in this TextLayout. Cannot be less than 0 or greater than this TextLayout object's character count.
Returns:: a hit whose caret appears at the next position to the left (top) of the caret of the provided hit, or null.

getVisualOtherHit

public TextHitInfo getVisualOtherHit(TextHitInfo hit)

Returns the hit on the opposite side of the specified hit's caret.

Parameters:: hit - the specified hit
Returns:: a hit that is on the opposite side of the specified hit's caret.

getCaretShape

public Shape getCaretShape(TextHitInfo hit,
                           Rectangle2D bounds)

Returns a Shape representing the caret at the specified hit inside the specified bounds.

Parameters:: hit - the hit at which to generate the caret; bounds - the bounds of the TextLayout to use in generating the caret.
Returns:: a Shape representing the caret.

getCaretShape

public Shape getCaretShape(TextHitInfo hit)

Returns a Shape representing the caret at the specified hit inside the natural bounds of this TextLayout.

Parameters:: hit - the hit at which to generate the caret
Returns:: a Shape representing the caret.

getCharacterLevel

public byte getCharacterLevel(int index)

Returns the level of the character at index. Indices -1 and characterCount are assigned the base level of this TextLayout.

Parameters:: index - the index of the character from which to get the level
Returns:: the level of the character at the specified index.

getCaretShapes

public Shape[] getCaretShapes(int offset,
                              Rectangle2D bounds,
                              TextLayout.CaretPolicy policy)

Returns two paths corresponding to the strong and weak caret.

Parameters:: offset - an offset in this TextLayout; bounds - the bounds to which to extend the carets; policy - the specified CaretPolicy
Returns:: an array of two paths. Element zero is the strong caret. If there are two carets, element one is the weak caret, otherwise it is null.

getCaretShapes

public Shape[] getCaretShapes(int offset,
                              Rectangle2D bounds)

Returns two paths corresponding to the strong and weak caret. This method is a convenience overload of getCaretShapes that uses the default caret policy.

Parameters:: offset - an offset in this TextLayout; bounds - the bounds to which to extend the carets
Returns:: two paths corresponding to the strong and weak caret as defined by the DEFAULT_CARET_POLICY

getCaretShapes

public Shape[] getCaretShapes(int offset)

Returns two paths corresponding to the strong and weak caret. This method is a convenience overload of getCaretShapes that uses the default caret policy and this TextLayout object's natural bounds.

Parameters:: offset - an offset in this TextLayout; bounds - the bounds to which to extend the carets
Returns:: two paths corresponding to the strong and weak caret as defined by the DEFAULT_CARET_POLICY

getLogicalRangesForVisualSelection

public int[] getLogicalRangesForVisualSelection(TextHitInfo firstEndpoint,
                                                TextHitInfo secondEndpoint)

Returns the logical ranges of text corresponding to a visual selection.

Parameters:: firstEndpoint - an endpoint of the visual range; secondEndpoint - the other endpoint of the visual range. This endpoint can be less than firstEndpoint.
Returns:: an array of integers representing start/limit pairs for the selected ranges.
See Also:: getVisualHighlightShape(TextHitInfo, TextHitInfo, Rectangle2D)

getVisualHighlightShape

public Shape getVisualHighlightShape(TextHitInfo firstEndpoint,
                                     TextHitInfo secondEndpoint,
                                     Rectangle2D bounds)

Returns a path enclosing the visual selection in the specified range, extended to bounds.

If the selection includes the leftmost (topmost) position, the selection is extended to the left (top) of bounds. If the selection includes the rightmost (bottommost) position, the selection is extended to the right (bottom) of the bounds. The height (width on vertical lines) of the selection is always extended to bounds.

Although the selection is always contiguous, the logically selected text can be discontiguous on lines with mixed-direction text. The logical ranges of text selected can be retrieved using getLogicalRangesForVisualSelection. For example, consider the text 'ABCdef' where capital letters indicate right-to-left text, rendered on a right-to-left line, with a visual selection from 0L (the leading edge of 'A') to 3T (the trailing edge of 'd'). The text appears as follows, with bold underlined areas representing the selection:

defCBA

The logical selection ranges are 0-3, 4-6 (ABC, ef) because the visually contiguous text is logically discontiguous. Also note that since the rightmost position on the layout (to the right of 'A') is selected, the selection is extended to the right of the bounds.

Parameters:: firstEndpoint - one end of the visual selection; secondEndpoint - the other end of the visual selection; bounds - the bounding rectangle to which to extend the selection
Returns:: a Shape enclosing the selection.
See Also:: getLogicalRangesForVisualSelection(TextHitInfo, TextHitInfo), getLogicalHighlightShape(int, int, Rectangle2D)

getVisualHighlightShape

public Shape getVisualHighlightShape(TextHitInfo firstEndpoint,
                                     TextHitInfo secondEndpoint)

Returns a Shape enclosing the visual selection in the specified range, extended to the bounds. This method is a convenience overload of getVisualHighlightShape that uses the natural bounds of this TextLayout.

Parameters:: firstEndpoint - one end of the visual selection; secondEndpoint - the other end of the visual selection
Returns:: a Shape enclosing the selection.

getLogicalHighlightShape

public Shape getLogicalHighlightShape(int firstEndpoint,
                                      int secondEndpoint,
                                      Rectangle2D bounds)

Returns a Shape enclosing the logical selection in the specified range, extended to the specified bounds.

If the selection range includes the first logical character, the selection is extended to the portion of bounds before the start of this TextLayout. If the range includes the last logical character, the selection is extended to the portion of bounds after the end of this TextLayout. The height (width on vertical lines) of the selection is always extended to bounds.

The selection can be discontiguous on lines with mixed-direction text. Only those characters in the logical range between start and limit appear selected. For example, consider the text 'ABCdef' where capital letters indicate right-to-left text, rendered on a right-to-left line, with a logical selection from 0 to 4 ('ABCd'). The text appears as follows, with bold standing in for the selection, and underlining for the extension:

defCBA

The selection is discontiguous because the selected characters are visually discontiguous. Also note that since the range includes the first logical character (A), the selection is extended to the portion of the bounds before the start of the layout, which in this case (a right-to-left line) is the right portion of the bounds.

Parameters:: firstEndpoint - an endpoint in the range of characters to select; secondEndpoint - the other endpoint of the range of characters to select. Can be less than firstEndpoint. The range includes the character at min(firstEndpoint, secondEndpoint), but excludes max(firstEndpoint, secondEndpoint).; bounds - the bounding rectangle to which to extend the selection
Returns:: an area enclosing the selection.
See Also:: getVisualHighlightShape(TextHitInfo, TextHitInfo, Rectangle2D)

getLogicalHighlightShape

public Shape getLogicalHighlightShape(int firstEndpoint,
                                      int secondEndpoint)

Returns a Shape enclosing the logical selection in the specified range, extended to the natural bounds of this TextLayout. This method is a convenience overload of getLogicalHighlightShape that uses the natural bounds of this TextLayout.

Parameters:: firstEndpoint - an endpoint in the range of characters to select; secondEndpoint - the other endpoint of the range of characters to select. Can be less than firstEndpoint. The range includes the character at min(firstEndpoint, secondEndpoint), but excludes max(firstEndpoint, secondEndpoint).
Returns:: a Shape enclosing the selection.

getBlackBoxBounds

public Shape getBlackBoxBounds(int firstEndpoint,
                               int secondEndpoint)

Returns the black box bounds of the characters in the specified range. The black box bounds is an area consisting of the union of the bounding boxes of all the glyphs corresponding to the characters between start and limit. This path may be disjoint.

Parameters:: firstEndpoint - one end of the character range; secondEndpoint - the other end of the character range. Can be less than firstEndpoint.
Returns:: a path enclosing the black box bounds.

hitTestChar

public TextHitInfo hitTestChar(float x,
                               float y,
                               Rectangle2D bounds)

Returns a TextHitInfo corresponding to the specified point. Coordinates outside the bounds of the TextLayout map to hits on the leading edge of the first logical character, or the trailing edge of the last logical character, as appropriate, regardless of the position of that character in the line. Only the direction along the baseline is used to make this evaluation.

Parameters:: x - the x offset from the origin of this TextLayout; y - the y offset from the origin of this TextLayout; bounds - the bounds of the TextLayout
Returns:: a hit describing the character and edge (leading or trailing) under the specified point.

hitTestChar

public TextHitInfo hitTestChar(float x,
                               float y)

Returns a TextHitInfo corresponding to the specified point. This method is a convenience overload of hitTestChar that uses the natural bounds of this TextLayout.

Parameters:: x - the x offset from the origin of this TextLayout; y - the y offset from the origin of this TextLayout
Returns:: a hit describing the character and edge (leading or trailing) under the specified point.

hashCode

public int hashCode()

Returns the hash code of this TextLayout.

Overrides:: hashCode in class Object

Returns:: the hash code of this TextLayout.

equals

public boolean equals(Object obj)

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

Overrides:: equals in class Object

Parameters:: obj - an Object to test for equality
Returns:: true if the specified Object equals this TextLayout; false otherwise.

equals

public boolean equals(TextLayout rhs)

Returns true if the two layouts are equal. Two layouts are equal if they contain equal glyphvectors in the same order.

Parameters:: rhs - the TextLayout to compare to this TextLayout
Returns:: true if the specified TextLayout equals this TextLayout.

toString

public String toString()

Returns debugging information for this TextLayout.

Overrides:: toString in class Object

Returns:: the textLine of this TextLayout as a String.

draw

public void draw(Graphics2D g2,
                 float x,
                 float y)

Renders this TextLayout at the specified location in the specified Graphics2D context. The origin of the layout is placed at x, y. Rendering may touch any point within getBounds() of this position. This leaves the g2 unchanged.

Parameters:: g2 - the Graphics2D context into which to render the layout; x, y - the coordinates of the origin of this TextLayout
See Also:: getBounds()

getOutline

public Shape getOutline(AffineTransform tx)

Returns a Shape representing the outline of this TextLayout.

Parameters:: tx - an optional AffineTransform to apply to the outline of this TextLayout.
Returns:: a Shape that is the outline of this TextLayout.

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Inner Class Summary
`static class`	`TextLayout.CaretPolicy` Defines a policy for determining the strong caret location.

Field Summary
`static TextLayout.CaretPolicy`	`DEFAULT_CARET_POLICY` This `CaretPolicy` is used when a policy is not specified by the client.

Constructor Summary
`TextLayout(AttributedCharacterIterator text, FontRenderContext frc)` Constructs a `TextLayout` from an iterator over styled text.
`TextLayout(String string, Font font, FontRenderContext frc)` Constructs a `TextLayout` from a `String` and a `Font`.
`TextLayout(String string, Map attributes, FontRenderContext frc)` Constructs a `TextLayout` from a `String` and an attribute set.

Method Summary
`protected Object`	`clone()` Creates a copy of this `TextLayout`.
`void`	`draw(Graphics2D g2, float x, float y)` Renders this `TextLayout` at the specified location in the specified `Graphics2D` context.
`boolean`	`equals(Object obj)` Returns `true` if the specified `Object` is a `TextLayout` object and if the specified `Object` equals this `TextLayout`.
`boolean`	`equals(TextLayout rhs)` Returns `true` if the two layouts are equal.
`float`	`getAdvance()` Returns the advance of this `TextLayout`.
`float`	`getAscent()` Returns the ascent of this `TextLayout`.
`byte`	`getBaseline()` Returns the baseline for this `TextLayout`.
`float[]`	`getBaselineOffsets()` Returns the offsets array for the baselines used for this `TextLayout`.
`Shape`	`getBlackBoxBounds(int firstEndpoint, int secondEndpoint)` Returns the black box bounds of the characters in the specified range.
`Rectangle2D`	`getBounds()` Returns the bounds of this `TextLayout`.
`float[]`	`getCaretInfo(TextHitInfo hit)` Returns information about the caret corresponding to `hit`.
`float[]`	`getCaretInfo(TextHitInfo hit, Rectangle2D bounds)` Returns information about the caret corresponding to `hit`.
`Shape`	`getCaretShape(TextHitInfo hit)` Returns a `Shape` representing the caret at the specified hit inside the natural bounds of this `TextLayout`.
`Shape`	`getCaretShape(TextHitInfo hit, Rectangle2D bounds)` Returns a `Shape` representing the caret at the specified hit inside the specified bounds.
`Shape[]`	`getCaretShapes(int offset)` Returns two paths corresponding to the strong and weak caret.
`Shape[]`	`getCaretShapes(int offset, Rectangle2D bounds)` Returns two paths corresponding to the strong and weak caret.
`Shape[]`	`getCaretShapes(int offset, Rectangle2D bounds, TextLayout.CaretPolicy policy)` Returns two paths corresponding to the strong and weak caret.
`int`	`getCharacterCount()` Returns the number of characters represented by this `TextLayout`.
`byte`	`getCharacterLevel(int index)` Returns the level of the character at `index`.
`float`	`getDescent()` Returns the descent of this `TextLayout`.
`TextLayout`	`getJustifiedLayout(float justificationWidth)` Creates a copy of this `TextLayout` justified to the specified width.
`float`	`getLeading()` Returns the leading of the `TextLayout`.
`Shape`	`getLogicalHighlightShape(int firstEndpoint, int secondEndpoint)` Returns a `Shape` enclosing the logical selection in the specified range, extended to the natural bounds of this `TextLayout`.
`Shape`	`getLogicalHighlightShape(int firstEndpoint, int secondEndpoint, Rectangle2D bounds)` Returns a `Shape` enclosing the logical selection in the specified range, extended to the specified `bounds`.
`int[]`	`getLogicalRangesForVisualSelection(TextHitInfo firstEndpoint, TextHitInfo secondEndpoint)` Returns the logical ranges of text corresponding to a visual selection.
`TextHitInfo`	`getNextLeftHit(int offset)` Returns the hit for the next caret to the left (top); if no such hit, returns `null`.
`TextHitInfo`	`getNextLeftHit(int offset, TextLayout.CaretPolicy policy)` Returns the hit for the next caret to the left (top); if no such hit, returns `null`.
`TextHitInfo`	`getNextLeftHit(TextHitInfo hit)` Returns the hit for the next caret to the left (top); if no such hit, returns `null`.
`TextHitInfo`	`getNextRightHit(int offset)` Returns the hit for the next caret to the right (bottom); if no such hit, returns `null`.
`TextHitInfo`	`getNextRightHit(int offset, TextLayout.CaretPolicy policy)` Returns the hit for the next caret to the right (bottom); if no such hit, returns `null`.
`TextHitInfo`	`getNextRightHit(TextHitInfo hit)` Returns the hit for the next caret to the right (bottom); if there is no such hit, returns `null`.
`Shape`	`getOutline(AffineTransform tx)` Returns a `Shape` representing the outline of this `TextLayout`.
`float`	`getVisibleAdvance()` Returns the advance of this `TextLayout`, minus trailing whitespace.
`Shape`	`getVisualHighlightShape(TextHitInfo firstEndpoint, TextHitInfo secondEndpoint)` Returns a `Shape` enclosing the visual selection in the specified range, extended to the bounds.
`Shape`	`getVisualHighlightShape(TextHitInfo firstEndpoint, TextHitInfo secondEndpoint, Rectangle2D bounds)` Returns a path enclosing the visual selection in the specified range, extended to `bounds`.
`TextHitInfo`	`getVisualOtherHit(TextHitInfo hit)` Returns the hit on the opposite side of the specified hit's caret.
`protected void`	`handleJustify(float justificationWidth)` Justify this layout.
`int`	`hashCode()` Returns the hash code of this `TextLayout`.
`TextHitInfo`	`hitTestChar(float x, float y)` Returns a `TextHitInfo` corresponding to the specified point.
`TextHitInfo`	`hitTestChar(float x, float y, Rectangle2D bounds)` Returns a `TextHitInfo` corresponding to the specified point.
`boolean`	`isLeftToRight()` Returns `true` if this `TextLayout` has a left-to-right base direction or `false` if it has a right-to-left base direction.
`boolean`	`isVertical()` Returns `true` if this `TextLayout` is vertical.
`String`	`toString()` Returns debugging information for this `TextLayout`.

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

java.awt.font Class TextLayout

DEFAULT_CARET_POLICY

TextLayout

TextLayout

TextLayout

clone

getJustifiedLayout

handleJustify

getBaseline

getBaselineOffsets

getAdvance

getVisibleAdvance

getAscent

getDescent

getLeading

getBounds

isLeftToRight

isVertical

getCharacterCount

getCaretInfo

getCaretInfo

getNextRightHit

getNextRightHit

getNextRightHit

getNextLeftHit

getNextLeftHit

getNextLeftHit

getVisualOtherHit

getCaretShape

getCaretShape

getCharacterLevel

getCaretShapes

getCaretShapes

getCaretShapes

getLogicalRangesForVisualSelection

getVisualHighlightShape

getVisualHighlightShape

getLogicalHighlightShape

getLogicalHighlightShape

getBlackBoxBounds

hitTestChar

hitTestChar

hashCode

equals

equals

toString

draw

getOutline

java.awt.font
Class TextLayout