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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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 * This code is free software; you can redistribute it and/or modify it
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 * particular file as subject to the "Classpath" exception as provided
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 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
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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.text.BreakIterator;
import java.text.CharacterIterator;
import java.text.AttributedCharacterIterator;
import java.awt.font.FontRenderContext;

The LineBreakMeasurer class allows styled text to be broken into lines (or segments) that fit within a particular visual advance. This is useful for clients who wish to display a paragraph of text that fits within a specific width, called the wrapping
width.
 LineBreakMeasurer is constructed with an iterator over styled text. The iterator's range should be a single paragraph in the text. LineBreakMeasurer maintains a position in the text for the start of the next text segment. Initially, this position is the start of text. Paragraphs are assigned an overall direction (either left-to-right or right-to-left) according to the bidirectional formatting rules. All segments obtained from a paragraph have the same direction as the paragraph. 
 Segments of text are obtained by calling the method nextLayout, which returns a TextLayout representing the text that fits within the wrapping width. The nextLayout method moves the current position to the end of the layout returned from nextLayout. 
 LineBreakMeasurer implements the most commonly used line-breaking policy: Every word that fits within the wrapping width is placed on the line. If the first word does not fit, then all of the characters that fit within the wrapping width are placed on the line. At least one character is placed on each line. 
 The TextLayout instances returned by LineBreakMeasurer treat tabs like 0-width spaces. Clients who wish to obtain tab-delimited segments for positioning should use the overload of nextLayout which takes a limiting offset in the text. The limiting offset should be the first character after the tab. The TextLayout objects returned from this method end at the limit provided (or before, if the text between the current position and the limit won't fit entirely within the wrapping width). 
 Clients who are laying out tab-delimited text need a slightly different line-breaking policy after the first segment has been placed on a line. Instead of fitting partial words in the remaining space, they should place words which don't fit in the remaining space entirely on the next line. This change of policy can be requested in the overload of nextLayout which takes a boolean parameter. If this parameter is true, nextLayout returns null if the first word won't fit in the given space. See the tab sample below. 
 In general, if the text used to construct the LineBreakMeasurer changes, a new LineBreakMeasurer must be constructed to reflect the change. (The old LineBreakMeasurer continues to function properly, but it won't be aware of the text change.) Nevertheless, if the text change is the insertion or deletion of a single character, an existing LineBreakMeasurer can be 'updated' by calling insertChar or deleteChar. Updating an existing LineBreakMeasurer is much faster than creating a new one. Clients who modify text based on user typing should take advantage of these methods. 

Examples:

Rendering a paragraph in a component


public void paint(Graphics graphics) {
    float dx = 0f, dy = 5f;
    Graphics2D g2d = (Graphics2D)graphics;
    FontRenderContext frc = g2d.getFontRenderContext();
    AttributedString text = new AttributedString(".....");
    AttributedCharacterIterator paragraph = text.getIterator();
    LineBreakMeasurer measurer = new LineBreakMeasurer(paragraph, frc);
    measurer.setPosition(paragraph.getBeginIndex());
    float wrappingWidth = (float)getSize().width;
    while (measurer.getPosition() < paragraph.getEndIndex()) {
        TextLayout layout = measurer.nextLayout(wrappingWidth);
        dy += (layout.getAscent());
        float dx = layout.isLeftToRight() ?
            0 : (wrappingWidth - layout.getAdvance());
        layout.draw(graphics, dx, dy);
        dy += layout.getDescent() + layout.getLeading();
    }
 }



Rendering text with tabs.  For simplicity, the overall text
direction is assumed to be left-to-right


public void paint(Graphics graphics) {
    float leftMargin = 10, rightMargin = 310;
    float[] tabStops = { 100, 250 };
    // assume styledText is an AttributedCharacterIterator, and the number
    // of tabs in styledText is tabCount
    int[] tabLocations = new int[tabCount+1];
    int i = 0;
    for (char c = styledText.first(); c != styledText.DONE; c = styledText.next()) {
        if (c == '\t') {
            tabLocations[i++] = styledText.getIndex();
        }
    }
    tabLocations[tabCount] = styledText.getEndIndex() - 1;
    // Now tabLocations has an entry for every tab's offset in
    // the text.  For convenience, the last entry is tabLocations
    // is the offset of the last character in the text.
    LineBreakMeasurer measurer = new LineBreakMeasurer(styledText);
    int currentTab = 0;
    float verticalPos = 20;
    while (measurer.getPosition() < styledText.getEndIndex()) {
        // Lay out and draw each line.  All segments on a line
        // must be computed before any drawing can occur, since
        // we must know the largest ascent on the line.
        // TextLayouts are computed and stored in a Vector;
        // their horizontal positions are stored in a parallel
        // Vector.
        // lineContainsText is true after first segment is drawn
        boolean lineContainsText = false;
        boolean lineComplete = false;
        float maxAscent = 0, maxDescent = 0;
        float horizontalPos = leftMargin;
        Vector layouts = new Vector(1);
        Vector penPositions = new Vector(1);
        while (!lineComplete) {
            float wrappingWidth = rightMargin - horizontalPos;
            TextLayout layout =
                    measurer.nextLayout(wrappingWidth,
                                        tabLocations[currentTab]+1,
                                        lineContainsText);
            // layout can be null if lineContainsText is true
            if (layout != null) {
                layouts.addElement(layout);
                penPositions.addElement(new Float(horizontalPos));
                horizontalPos += layout.getAdvance();
                maxAscent = Math.max(maxAscent, layout.getAscent());
                maxDescent = Math.max(maxDescent,
                    layout.getDescent() + layout.getLeading());
            } else {
                lineComplete = true;
            }
            lineContainsText = true;
            if (measurer.getPosition() == tabLocations[currentTab]+1) {
                currentTab++;
            }
            if (measurer.getPosition() == styledText.getEndIndex())
                lineComplete = true;
            else if (horizontalPos >= tabStops[tabStops.length-1])
                lineComplete = true;
            if (!lineComplete) {
                // move to next tab stop
                int j;
                for (j=0; horizontalPos >= tabStops[j]; j++) {}
                horizontalPos = tabStops[j];
            }
        }
        verticalPos += maxAscent;
        Enumeration layoutEnum = layouts.elements();
        Enumeration positionEnum = penPositions.elements();
        // now iterate through layouts and draw them
        while (layoutEnum.hasMoreElements()) {
            TextLayout nextLayout = (TextLayout) layoutEnum.nextElement();
            Float nextPosition = (Float) positionEnum.nextElement();
            nextLayout.draw(graphics, nextPosition.floatValue(), verticalPos);
        }
        verticalPos += maxDescent;
    }
 }


See Also:
TextLayout/**
 * The {@code LineBreakMeasurer} class allows styled text to be
 * broken into lines (or segments) that fit within a particular visual
 * advance.  This is useful for clients who wish to display a paragraph of
 * text that fits within a specific width, called the <b>wrapping
 * width</b>.
 * <p>
 * {@code LineBreakMeasurer} is constructed with an iterator over
 * styled text.  The iterator's range should be a single paragraph in the
 * text.
 * {@code LineBreakMeasurer} maintains a position in the text for the
 * start of the next text segment.  Initially, this position is the
 * start of text.  Paragraphs are assigned an overall direction (either
 * left-to-right or right-to-left) according to the bidirectional
 * formatting rules.  All segments obtained from a paragraph have the
 * same direction as the paragraph.
 * <p>
 * Segments of text are obtained by calling the method
 * {@code nextLayout}, which returns a {@link TextLayout}
 * representing the text that fits within the wrapping width.
 * The {@code nextLayout} method moves the current position
 * to the end of the layout returned from {@code nextLayout}.
 * <p>
 * {@code LineBreakMeasurer} implements the most commonly used
 * line-breaking policy: Every word that fits within the wrapping
 * width is placed on the line. If the first word does not fit, then all
 * of the characters that fit within the wrapping width are placed on the
 * line.  At least one character is placed on each line.
 * <p>
 * The {@code TextLayout} instances returned by
 * {@code LineBreakMeasurer} treat tabs like 0-width spaces.  Clients
 * who wish to obtain tab-delimited segments for positioning should use
 * the overload of {@code nextLayout} which takes a limiting offset
 * in the text.
 * The limiting offset should be the first character after the tab.
 * The {@code TextLayout} objects returned from this method end
 * at the limit provided (or before, if the text between the current
 * position and the limit won't fit entirely within the  wrapping
 * width).
 * <p>
 * Clients who are laying out tab-delimited text need a slightly
 * different line-breaking policy after the first segment has been
 * placed on a line.  Instead of fitting partial words in the
 * remaining space, they should place words which don't fit in the
 * remaining space entirely on the next line.  This change of policy
 * can be requested in the overload of {@code nextLayout} which
 * takes a {@code boolean} parameter.  If this parameter is
 * {@code true}, {@code nextLayout} returns
 * {@code null} if the first word won't fit in
 * the given space.  See the tab sample below.
 * <p>
 * In general, if the text used to construct the
 * {@code LineBreakMeasurer} changes, a new
 * {@code LineBreakMeasurer} must be constructed to reflect
 * the change.  (The old {@code LineBreakMeasurer} continues to
 * function properly, but it won't be aware of the text change.)
 * Nevertheless, if the text change is the insertion or deletion of a
 * single character, an existing {@code LineBreakMeasurer} can be
 * 'updated' by calling {@code insertChar} or
 * {@code deleteChar}. Updating an existing
 * {@code LineBreakMeasurer} is much faster than creating a new one.
 * Clients who modify text based on user typing should take advantage
 * of these methods.
 * <p>
 * <strong>Examples</strong>:<p>
 * Rendering a paragraph in a component
 * <blockquote>
 * <pre>{@code
 * public void paint(Graphics graphics) {
 *
 *     float dx = 0f, dy = 5f;
 *     Graphics2D g2d = (Graphics2D)graphics;
 *     FontRenderContext frc = g2d.getFontRenderContext();
 *
 *     AttributedString text = new AttributedString(".....");
 *     AttributedCharacterIterator paragraph = text.getIterator();
 *
 *     LineBreakMeasurer measurer = new LineBreakMeasurer(paragraph, frc);
 *     measurer.setPosition(paragraph.getBeginIndex());
 *     float wrappingWidth = (float)getSize().width;
 *
 *     while (measurer.getPosition() < paragraph.getEndIndex()) {
 *
 *         TextLayout layout = measurer.nextLayout(wrappingWidth);
 *
 *         dy += (layout.getAscent());
 *         float dx = layout.isLeftToRight() ?
 *             0 : (wrappingWidth - layout.getAdvance());
 *
 *         layout.draw(graphics, dx, dy);
 *         dy += layout.getDescent() + layout.getLeading();
 *     }
 * }
 * }</pre>
 * </blockquote>
 * <p>
 * Rendering text with tabs.  For simplicity, the overall text
 * direction is assumed to be left-to-right
 * <blockquote>
 * <pre>{@code
 * public void paint(Graphics graphics) {
 *
 *     float leftMargin = 10, rightMargin = 310;
 *     float[] tabStops = { 100, 250 };
 *
 *     // assume styledText is an AttributedCharacterIterator, and the number
 *     // of tabs in styledText is tabCount
 *
 *     int[] tabLocations = new int[tabCount+1];
 *
 *     int i = 0;
 *     for (char c = styledText.first(); c != styledText.DONE; c = styledText.next()) {
 *         if (c == '\t') {
 *             tabLocations[i++] = styledText.getIndex();
 *         }
 *     }
 *     tabLocations[tabCount] = styledText.getEndIndex() - 1;
 *
 *     // Now tabLocations has an entry for every tab's offset in
 *     // the text.  For convenience, the last entry is tabLocations
 *     // is the offset of the last character in the text.
 *
 *     LineBreakMeasurer measurer = new LineBreakMeasurer(styledText);
 *     int currentTab = 0;
 *     float verticalPos = 20;
 *
 *     while (measurer.getPosition() < styledText.getEndIndex()) {
 *
 *         // Lay out and draw each line.  All segments on a line
 *         // must be computed before any drawing can occur, since
 *         // we must know the largest ascent on the line.
 *         // TextLayouts are computed and stored in a Vector;
 *         // their horizontal positions are stored in a parallel
 *         // Vector.
 *
 *         // lineContainsText is true after first segment is drawn
 *         boolean lineContainsText = false;
 *         boolean lineComplete = false;
 *         float maxAscent = 0, maxDescent = 0;
 *         float horizontalPos = leftMargin;
 *         Vector layouts = new Vector(1);
 *         Vector penPositions = new Vector(1);
 *
 *         while (!lineComplete) {
 *             float wrappingWidth = rightMargin - horizontalPos;
 *             TextLayout layout =
 *                     measurer.nextLayout(wrappingWidth,
 *                                         tabLocations[currentTab]+1,
 *                                         lineContainsText);
 *
 *             // layout can be null if lineContainsText is true
 *             if (layout != null) {
 *                 layouts.addElement(layout);
 *                 penPositions.addElement(new Float(horizontalPos));
 *                 horizontalPos += layout.getAdvance();
 *                 maxAscent = Math.max(maxAscent, layout.getAscent());
 *                 maxDescent = Math.max(maxDescent,
 *                     layout.getDescent() + layout.getLeading());
 *             } else {
 *                 lineComplete = true;
 *             }
 *
 *             lineContainsText = true;
 *
 *             if (measurer.getPosition() == tabLocations[currentTab]+1) {
 *                 currentTab++;
 *             }
 *
 *             if (measurer.getPosition() == styledText.getEndIndex())
 *                 lineComplete = true;
 *             else if (horizontalPos >= tabStops[tabStops.length-1])
 *                 lineComplete = true;
 *
 *             if (!lineComplete) {
 *                 // move to next tab stop
 *                 int j;
 *                 for (j=0; horizontalPos >= tabStops[j]; j++) {}
 *                 horizontalPos = tabStops[j];
 *             }
 *         }
 *
 *         verticalPos += maxAscent;
 *
 *         Enumeration layoutEnum = layouts.elements();
 *         Enumeration positionEnum = penPositions.elements();
 *
 *         // now iterate through layouts and draw them
 *         while (layoutEnum.hasMoreElements()) {
 *             TextLayout nextLayout = (TextLayout) layoutEnum.nextElement();
 *             Float nextPosition = (Float) positionEnum.nextElement();
 *             nextLayout.draw(graphics, nextPosition.floatValue(), verticalPos);
 *         }
 *
 *         verticalPos += maxDescent;
 *     }
 * }
 * }</pre>
 * </blockquote>
 * @see TextLayout
 */

public final class LineBreakMeasurer {

    private BreakIterator breakIter;
    private int start;
    private int pos;
    private int limit;
    private TextMeasurer measurer;
    private CharArrayIterator charIter;

    
Constructs a LineBreakMeasurer for the specified text. 
Params:
text – the text for which this LineBreakMeasurer produces TextLayout objects; the text must contain at least one character; if the text available through iter changes, further calls to this LineBreakMeasurer instance are undefined (except, in some cases, when insertChar or deleteChar are invoked afterward - see below)
frc – contains information about a graphics device which is needed to measure the text correctly; text measurements can vary slightly depending on the device resolution, and attributes such as antialiasing; this parameter does not specify a translation between the LineBreakMeasurer and user space
See Also:
insertChar
deleteChar/**
     * Constructs a {@code LineBreakMeasurer} for the specified text.
     *
     * @param text the text for which this {@code LineBreakMeasurer}
     *       produces {@code TextLayout} objects; the text must contain
     *       at least one character; if the text available through
     *       {@code iter} changes, further calls to this
     *       {@code LineBreakMeasurer} instance are undefined (except,
     *       in some cases, when {@code insertChar} or
     *       {@code deleteChar} are invoked afterward - see below)
     * @param frc contains information about a graphics device which is
     *       needed to measure the text correctly;
     *       text measurements can vary slightly depending on the
     *       device resolution, and attributes such as antialiasing; this
     *       parameter does not specify a translation between the
     *       {@code LineBreakMeasurer} and user space
     * @see LineBreakMeasurer#insertChar
     * @see LineBreakMeasurer#deleteChar
     */
    public LineBreakMeasurer(AttributedCharacterIterator text, FontRenderContext frc) {
        this(text, BreakIterator.getLineInstance(), frc);
    }

    
Constructs a LineBreakMeasurer for the specified text. 
Params:
text – the text for which this LineBreakMeasurer produces TextLayout objects; the text must contain at least one character; if the text available through iter changes, further calls to this LineBreakMeasurer instance are undefined (except, in some cases, when insertChar or deleteChar are invoked afterward - see below)
breakIter – the BreakIterator which defines line breaks
frc – contains information about a graphics device which is needed to measure the text correctly; text measurements can vary slightly depending on the device resolution, and attributes such as antialiasing; this parameter does not specify a translation between the LineBreakMeasurer and user space
Throws:
IllegalArgumentException – if the text has less than one character
See Also:
insertChar
deleteChar/**
     * Constructs a {@code LineBreakMeasurer} for the specified text.
     *
     * @param text the text for which this {@code LineBreakMeasurer}
     *     produces {@code TextLayout} objects; the text must contain
     *     at least one character; if the text available through
     *     {@code iter} changes, further calls to this
     *     {@code LineBreakMeasurer} instance are undefined (except,
     *     in some cases, when {@code insertChar} or
     *     {@code deleteChar} are invoked afterward - see below)
     * @param breakIter the {@link BreakIterator} which defines line
     *     breaks
     * @param frc contains information about a graphics device which is
     *       needed to measure the text correctly;
     *       text measurements can vary slightly depending on the
     *       device resolution, and attributes such as antialiasing; this
     *       parameter does not specify a translation between the
     *       {@code LineBreakMeasurer} and user space
     * @throws IllegalArgumentException if the text has less than one character
     * @see LineBreakMeasurer#insertChar
     * @see LineBreakMeasurer#deleteChar
     */
    public LineBreakMeasurer(AttributedCharacterIterator text,
                             BreakIterator breakIter,
                             FontRenderContext frc) {
        if (text.getEndIndex() - text.getBeginIndex() < 1) {
            throw new IllegalArgumentException("Text must contain at least one character.");
        }

        this.breakIter = breakIter;
        this.measurer = new TextMeasurer(text, frc);
        this.limit = text.getEndIndex();
        this.pos = this.start = text.getBeginIndex();

        charIter = new CharArrayIterator(measurer.getChars(), this.start);
        this.breakIter.setText(charIter);
    }

    
Returns the position at the end of the next layout. Does NOT update the current position of this LineBreakMeasurer. 
Params:
wrappingWidth – the maximum visible advance permitted for
   the text in the next layout
Returns:
an offset in the text representing the limit of the next TextLayout./**
     * Returns the position at the end of the next layout.  Does NOT
     * update the current position of this {@code LineBreakMeasurer}.
     *
     * @param wrappingWidth the maximum visible advance permitted for
     *    the text in the next layout
     * @return an offset in the text representing the limit of the
     *    next {@code TextLayout}.
     */
    public int nextOffset(float wrappingWidth) {
        return nextOffset(wrappingWidth, limit, false);
    }

    
Returns the position at the end of the next layout. Does NOT update the current position of this LineBreakMeasurer. 
Params:
wrappingWidth – the maximum visible advance permitted for
   the text in the next layout
offsetLimit – the first character that can not be included in the next layout, even if the text after the limit would fit within the wrapping width; offsetLimit must be greater than the current position
requireNextWord – if true, the current position that is returned if the entire next word does not fit within wrappingWidth; if false, the offset returned is at least one greater than the current position
Returns:
an offset in the text representing the limit of the next TextLayout/**
     * Returns the position at the end of the next layout.  Does NOT
     * update the current position of this {@code LineBreakMeasurer}.
     *
     * @param wrappingWidth the maximum visible advance permitted for
     *    the text in the next layout
     * @param offsetLimit the first character that can not be included
     *    in the next layout, even if the text after the limit would fit
     *    within the wrapping width; {@code offsetLimit} must be
     *    greater than the current position
     * @param requireNextWord if {@code true}, the current position
     *    that is returned if the entire next word does not fit within
     *    {@code wrappingWidth}; if {@code false}, the offset
     *    returned is at least one greater than the current position
     * @return an offset in the text representing the limit of the
     *    next {@code TextLayout}
     */
    public int nextOffset(float wrappingWidth, int offsetLimit,
                          boolean requireNextWord) {

        int nextOffset = pos;

        if (pos < limit) {
            if (offsetLimit <= pos) {
                    throw new IllegalArgumentException("offsetLimit must be after current position");
            }

            int charAtMaxAdvance =
                            measurer.getLineBreakIndex(pos, wrappingWidth);

            if (charAtMaxAdvance == limit) {
                nextOffset = limit;
            }
            else if (Character.isWhitespace(measurer.getChars()[charAtMaxAdvance-start])) {
                nextOffset = breakIter.following(charAtMaxAdvance);
            }
            else {
            // Break is in a word;  back up to previous break.

                // NOTE:  I think that breakIter.preceding(limit) should be
                // equivalent to breakIter.last(), breakIter.previous() but
                // the authors of BreakIterator thought otherwise...
                // If they were equivalent then the first branch would be
                // unnecessary.
                int testPos = charAtMaxAdvance + 1;
                if (testPos == limit) {
                    breakIter.last();
                    nextOffset = breakIter.previous();
                }
                else {
                    nextOffset = breakIter.preceding(testPos);
                }

                if (nextOffset <= pos) {
                    // first word doesn't fit on line
                    if (requireNextWord) {
                        nextOffset = pos;
                    }
                    else {
                        nextOffset = Math.max(pos+1, charAtMaxAdvance);
                    }
                }
            }
        }

        if (nextOffset > offsetLimit) {
            nextOffset = offsetLimit;
        }

        return nextOffset;
    }

    
Returns the next layout, and updates the current position.
Params:
wrappingWidth – the maximum visible advance permitted for
    the text in the next layout
Returns:
a TextLayout, beginning at the current position, which represents the next line fitting within wrappingWidth/**
     * Returns the next layout, and updates the current position.
     *
     * @param wrappingWidth the maximum visible advance permitted for
     *     the text in the next layout
     * @return a {@code TextLayout}, beginning at the current
     *     position, which represents the next line fitting within
     *     {@code wrappingWidth}
     */
    public TextLayout nextLayout(float wrappingWidth) {
        return nextLayout(wrappingWidth, limit, false);
    }

    
Returns the next layout, and updates the current position.
Params:
wrappingWidth – the maximum visible advance permitted
   for the text in the next layout
offsetLimit – the first character that can not be included in the next layout, even if the text after the limit would fit within the wrapping width; offsetLimit must be greater than the current position
requireNextWord – if true, and if the entire word at the current position does not fit within the wrapping width, null is returned. If false, a valid layout is returned that includes at least the character at the current position
Returns:
a TextLayout, beginning at the current position, that represents the next line fitting within wrappingWidth. If the current position is at the end of the text used by this LineBreakMeasurer, null is returned/**
     * Returns the next layout, and updates the current position.
     *
     * @param wrappingWidth the maximum visible advance permitted
     *    for the text in the next layout
     * @param offsetLimit the first character that can not be
     *    included in the next layout, even if the text after the limit
     *    would fit within the wrapping width; {@code offsetLimit}
     *    must be greater than the current position
     * @param requireNextWord if {@code true}, and if the entire word
     *    at the current position does not fit within the wrapping width,
     *    {@code null} is returned. If {@code false}, a valid
     *    layout is returned that includes at least the character at the
     *    current position
     * @return a {@code TextLayout}, beginning at the current
     *    position, that represents the next line fitting within
     *    {@code wrappingWidth}.  If the current position is at the end
     *    of the text used by this {@code LineBreakMeasurer},
     *    {@code null} is returned
     */
    public TextLayout nextLayout(float wrappingWidth, int offsetLimit,
                                 boolean requireNextWord) {

        if (pos < limit) {
            int layoutLimit = nextOffset(wrappingWidth, offsetLimit, requireNextWord);
            if (layoutLimit == pos) {
                return null;
            }

            TextLayout result = measurer.getLayout(pos, layoutLimit);
            pos = layoutLimit;

            return result;
        } else {
            return null;
        }
    }

    
Returns the current position of this LineBreakMeasurer. 
See Also:
setPosition
Returns:
the current position of this LineBreakMeasurer/**
     * Returns the current position of this {@code LineBreakMeasurer}.
     *
     * @return the current position of this {@code LineBreakMeasurer}
     * @see #setPosition
     */
    public int getPosition() {
        return pos;
    }

    
Sets the current position of this LineBreakMeasurer. 
Params:
newPosition – the current position of this LineBreakMeasurer; the position should be within the text used to construct this LineBreakMeasurer (or in the text most recently passed to insertChar or deleteChar
See Also:
getPosition/**
     * Sets the current position of this {@code LineBreakMeasurer}.
     *
     * @param newPosition the current position of this
     *    {@code LineBreakMeasurer}; the position should be within the
     *    text used to construct this {@code LineBreakMeasurer} (or in
     *    the text most recently passed to {@code insertChar}
     *    or {@code deleteChar}
     * @see #getPosition
     */
    public void setPosition(int newPosition) {
        if (newPosition < start || newPosition > limit) {
            throw new IllegalArgumentException("position is out of range");
        }
        pos = newPosition;
    }

    
Updates this LineBreakMeasurer after a single character is inserted into the text, and sets the current position to the beginning of the paragraph. 
Params:
newParagraph – the text after the insertion
insertPos – the position in the text at which the character
   is inserted
Throws:
IndexOutOfBoundsException – if insertPos is less than the start of newParagraph or greater than or equal to the end of newParagraph
NullPointerException – if newParagraph is null
See Also:
deleteChar/**
     * Updates this {@code LineBreakMeasurer} after a single
     * character is inserted into the text, and sets the current
     * position to the beginning of the paragraph.
     *
     * @param newParagraph the text after the insertion
     * @param insertPos the position in the text at which the character
     *    is inserted
     * @throws IndexOutOfBoundsException if {@code insertPos} is less
     *         than the start of {@code newParagraph} or greater than
     *         or equal to the end of {@code newParagraph}
     * @throws NullPointerException if {@code newParagraph} is
     *         {@code null}
     * @see #deleteChar
     */
    public void insertChar(AttributedCharacterIterator newParagraph,
                           int insertPos) {

        measurer.insertChar(newParagraph, insertPos);

        limit = newParagraph.getEndIndex();
        pos = start = newParagraph.getBeginIndex();

        charIter.reset(measurer.getChars(), newParagraph.getBeginIndex());
        breakIter.setText(charIter);
    }

    
Updates this LineBreakMeasurer after a single character is deleted from the text, and sets the current position to the beginning of the paragraph. 
Params:
newParagraph – the text after the deletion
deletePos – the position in the text at which the character
   is deleted
Throws:
IndexOutOfBoundsException – if deletePos is less than the start of newParagraph or greater than the end of newParagraph
NullPointerException – if newParagraph is null
See Also:
insertChar/**
     * Updates this {@code LineBreakMeasurer} after a single
     * character is deleted from the text, and sets the current
     * position to the beginning of the paragraph.
     * @param newParagraph the text after the deletion
     * @param deletePos the position in the text at which the character
     *    is deleted
     * @throws IndexOutOfBoundsException if {@code deletePos} is
     *         less than the start of {@code newParagraph} or greater
     *         than the end of {@code newParagraph}
     * @throws NullPointerException if {@code newParagraph} is
     *         {@code null}
     * @see #insertChar
     */
    public void deleteChar(AttributedCharacterIterator newParagraph,
                           int deletePos) {

        measurer.deleteChar(newParagraph, deletePos);

        limit = newParagraph.getEndIndex();
        pos = start = newParagraph.getBeginIndex();

        charIter.reset(measurer.getChars(), start);
        breakIter.setText(charIter);
    }
}