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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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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
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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.awt.Font;

import java.text.AttributedCharacterIterator;
import java.text.AttributedCharacterIterator.Attribute;
import java.text.AttributedString;
import java.text.Bidi;
import java.text.BreakIterator;
import java.text.CharacterIterator;

import java.awt.font.FontRenderContext;

import java.util.Hashtable;
import java.util.Map;

import sun.font.AttributeValues;
import sun.font.BidiUtils;
import sun.font.TextLineComponent;
import sun.font.TextLabelFactory;
import sun.font.FontResolver;


The TextMeasurer class provides the primitive operations needed for line break: measuring up to a given advance, determining the advance of a range of characters, and generating a TextLayout for a range of characters. It also provides methods for incremental editing of paragraphs. 
 A TextMeasurer object is constructed with an AttributedCharacterIterator representing a single paragraph of text. The value returned by the getBeginIndex method of AttributedCharacterIterator defines the absolute index of the first character. The value returned by the getEndIndex method of AttributedCharacterIterator defines the index past the last character. These values define the range of indexes to use in calls to the TextMeasurer. For example, calls to get the advance of a range of text or the line break of a range of text must use indexes between the beginning and end index values. Calls to insertChar and deleteChar reset the TextMeasurer to use the beginning index and end index of the AttributedCharacterIterator passed in those calls. 
 Most clients will use the more convenient LineBreakMeasurer, which implements the standard line break policy (placing as many words as will fit on each line). 
Author:John Raley
See Also:
Since:1.3
/**
 * The {@code TextMeasurer} class provides the primitive operations
 * needed for line break: measuring up to a given advance, determining the
 * advance of a range of characters, and generating a
 * {@code TextLayout} for a range of characters. It also provides
 * methods for incremental editing of paragraphs.
 * <p>
 * A {@code TextMeasurer} object is constructed with an
 * {@link java.text.AttributedCharacterIterator AttributedCharacterIterator}
 * representing a single paragraph of text.  The value returned by the
 * {@link AttributedCharacterIterator#getBeginIndex() getBeginIndex}
 * method of {@code AttributedCharacterIterator}
 * defines the absolute index of the first character.  The value
 * returned by the
 * {@link AttributedCharacterIterator#getEndIndex() getEndIndex}
 * method of {@code AttributedCharacterIterator} defines the index
 * past the last character.  These values define the range of indexes to
 * use in calls to the {@code TextMeasurer}.  For example, calls to
 * get the advance of a range of text or the line break of a range of text
 * must use indexes between the beginning and end index values.  Calls to
 * {@link #insertChar(java.text.AttributedCharacterIterator, int) insertChar}
 * and
 * {@link #deleteChar(java.text.AttributedCharacterIterator, int) deleteChar}
 * reset the {@code TextMeasurer} to use the beginning index and end
 * index of the {@code AttributedCharacterIterator} passed in those calls.
 * <p>
 * Most clients will use the more convenient {@code LineBreakMeasurer},
 * which implements the standard line break policy (placing as many words
 * as will fit on each line).
 *
 * @author John Raley
 * @see LineBreakMeasurer
 * @since 1.3
 */

public final class TextMeasurer implements Cloneable {

    // Number of lines to format to.
    private static float EST_LINES = (float) 2.1;

    /*
    static {
        String s = System.getProperty("estLines");
        if (s != null) {
            try {
                Float f = Float.valueOf(s);
                EST_LINES = f.floatValue();
            }
            catch(NumberFormatException e) {
            }
        }
        //System.out.println("EST_LINES="+EST_LINES);
    }
    */

    private FontRenderContext fFrc;

    private int fStart;

    // characters in source text
    private char[] fChars;

    // Bidi for this paragraph
    private Bidi fBidi;

    // Levels array for chars in this paragraph - needed to reorder
    // trailing counterdirectional whitespace
    private byte[] fLevels;

    // line components in logical order
    private TextLineComponent[] fComponents;

    // index where components begin
    private int fComponentStart;

    // index where components end
    private int fComponentLimit;

    private boolean haveLayoutWindow;

    // used to find valid starting points for line components
    private BreakIterator fLineBreak = null;
    private CharArrayIterator charIter = null;
    int layoutCount = 0;
    int layoutCharCount = 0;

    // paragraph, with resolved fonts and styles
    private StyledParagraph fParagraph;

    // paragraph data - same across all layouts
    private boolean fIsDirectionLTR;
    private byte fBaseline;
    private float[] fBaselineOffsets;
    private float fJustifyRatio = 1;

    
Constructs a TextMeasurer from the source text. The source text should be a single entire paragraph. 
Params:
  • text – the source paragraph.  Cannot be null.
  • frc – the information about a graphics device which is needed
      to measure the text correctly.  Cannot be null.
/**
     * Constructs a {@code TextMeasurer} from the source text.
     * The source text should be a single entire paragraph.
     * @param text the source paragraph.  Cannot be null.
     * @param frc the information about a graphics device which is needed
     *       to measure the text correctly.  Cannot be null.
     */
    public TextMeasurer(AttributedCharacterIterator text, FontRenderContext frc) {

        fFrc = frc;
        initAll(text);
    }

    protected Object clone() {
        TextMeasurer other;
        try {
            other = (TextMeasurer) super.clone();
        }
        catch(CloneNotSupportedException e) {
            throw new Error();
        }
        if (fComponents != null) {
            other.fComponents = fComponents.clone();
        }
        return other;
    }

    private void invalidateComponents() {
        fComponentStart = fComponentLimit = fChars.length;
        fComponents = null;
        haveLayoutWindow = false;
    }

    
Initialize state, including fChars array, direction, and
fBidi.

/**
     * Initialize state, including fChars array, direction, and
     * fBidi.
     */
    private void initAll(AttributedCharacterIterator text) {

        fStart = text.getBeginIndex();

        // extract chars
        fChars = new char[text.getEndIndex() - fStart];

        int n = 0;
        for (char c = text.first();
             c != CharacterIterator.DONE;
             c = text.next())
        {
            fChars[n++] = c;
        }

        text.first();

        fBidi = new Bidi(text);
        if (fBidi.isLeftToRight()) {
            fBidi = null;
        }

        text.first();
        Map<? extends Attribute, ?> paragraphAttrs = text.getAttributes();
        NumericShaper shaper = AttributeValues.getNumericShaping(paragraphAttrs);
        if (shaper != null) {
            shaper.shape(fChars, 0, fChars.length);
        }

        fParagraph = new StyledParagraph(text, fChars);

        // set paragraph attributes
        {
            // If there's an embedded graphic at the start of the
            // paragraph, look for the first non-graphic character
            // and use it and its font to initialize the paragraph.
            // If not, use the first graphic to initialize.
            fJustifyRatio = AttributeValues.getJustification(paragraphAttrs);

            boolean haveFont = TextLine.advanceToFirstFont(text);

            if (haveFont) {
                Font defaultFont = TextLine.getFontAtCurrentPos(text);
                int charsStart = text.getIndex() - text.getBeginIndex();
                LineMetrics lm = defaultFont.getLineMetrics(fChars, charsStart, charsStart+1, fFrc);
                fBaseline = (byte) lm.getBaselineIndex();
                fBaselineOffsets = lm.getBaselineOffsets();
            }
            else {
                // hmmm what to do here?  Just try to supply reasonable
                // values I guess.

                GraphicAttribute graphic = (GraphicAttribute)
                                paragraphAttrs.get(TextAttribute.CHAR_REPLACEMENT);
                fBaseline = TextLayout.getBaselineFromGraphic(graphic);
                Hashtable<Attribute, ?> fmap = new Hashtable<>(5, (float)0.9);
                Font dummyFont = new Font(fmap);
                LineMetrics lm = dummyFont.getLineMetrics(" ", 0, 1, fFrc);
                fBaselineOffsets = lm.getBaselineOffsets();
            }
            fBaselineOffsets = TextLine.getNormalizedOffsets(fBaselineOffsets, fBaseline);
        }

        invalidateComponents();
    }

    
Generate components for the paragraph.  fChars, fBidi should have been
initialized already.

/**
     * Generate components for the paragraph.  fChars, fBidi should have been
     * initialized already.
     */
    private void generateComponents(int startingAt, int endingAt) {

        if (collectStats) {
            formattedChars += (endingAt-startingAt);
        }
        int layoutFlags = 0; // no extra info yet, bidi determines run and line direction
        TextLabelFactory factory = new TextLabelFactory(fFrc, fChars, fBidi, layoutFlags);

        int[] charsLtoV = null;

        if (fBidi != null) {
            fLevels = BidiUtils.getLevels(fBidi);
            int[] charsVtoL = BidiUtils.createVisualToLogicalMap(fLevels);
            charsLtoV = BidiUtils.createInverseMap(charsVtoL);
            fIsDirectionLTR = fBidi.baseIsLeftToRight();
        }
        else {
            fLevels = null;
            fIsDirectionLTR = true;
        }

        try {
            fComponents = TextLine.getComponents(
                fParagraph, fChars, startingAt, endingAt, charsLtoV, fLevels, factory);
        }
        catch(IllegalArgumentException e) {
            System.out.println("startingAt="+startingAt+"; endingAt="+endingAt);
            System.out.println("fComponentLimit="+fComponentLimit);
            throw e;
        }

        fComponentStart = startingAt;
        fComponentLimit = endingAt;
        //debugFormatCount += (endingAt-startingAt);
    }

    private int calcLineBreak(final int pos, final float maxAdvance) {

        // either of these statements removes the bug:
        //generateComponents(0, fChars.length);
        //generateComponents(pos, fChars.length);

        int startPos = pos;
        float width = maxAdvance;

        int tlcIndex;
        int tlcStart = fComponentStart;

        for (tlcIndex = 0; tlcIndex < fComponents.length; tlcIndex++) {
            int gaLimit = tlcStart + fComponents[tlcIndex].getNumCharacters();
            if (gaLimit > startPos) {
                break;
            }
            else {
                tlcStart = gaLimit;
            }
        }

        // tlcStart is now the start of the tlc at tlcIndex

        for (; tlcIndex < fComponents.length; tlcIndex++) {

            TextLineComponent tlc = fComponents[tlcIndex];
            int numCharsInGa = tlc.getNumCharacters();

            int lineBreak = tlc.getLineBreakIndex(startPos - tlcStart, width);
            if (lineBreak == numCharsInGa && tlcIndex < fComponents.length) {
                width -= tlc.getAdvanceBetween(startPos - tlcStart, lineBreak);
                tlcStart += numCharsInGa;
                startPos = tlcStart;
            }
            else {
                return tlcStart + lineBreak;
            }
        }

        if (fComponentLimit < fChars.length) {
            // format more text and try again
            //if (haveLayoutWindow) {
            //    outOfWindow++;
            //}

            generateComponents(pos, fChars.length);
            return calcLineBreak(pos, maxAdvance);
        }

        return fChars.length;
    }

    
According to the Unicode Bidirectional Behavior specification
(Unicode Standard 2.0, section 3.11), whitespace at the ends
of lines which would naturally flow against the base direction
must be made to flow with the line direction, and moved to the
end of the line.  This method returns the start of the sequence
of trailing whitespace characters to move to the end of a
line taken from the given range.

/**
     * According to the Unicode Bidirectional Behavior specification
     * (Unicode Standard 2.0, section 3.11), whitespace at the ends
     * of lines which would naturally flow against the base direction
     * must be made to flow with the line direction, and moved to the
     * end of the line.  This method returns the start of the sequence
     * of trailing whitespace characters to move to the end of a
     * line taken from the given range.
     */
    private int trailingCdWhitespaceStart(int startPos, int limitPos) {

        if (fLevels != null) {
            // Back up over counterdirectional whitespace
            final byte baseLevel = (byte) (fIsDirectionLTR? 0 : 1);
            for (int cdWsStart = limitPos; --cdWsStart >= startPos;) {
                if ((fLevels[cdWsStart] % 2) == baseLevel ||
                        Character.getDirectionality(fChars[cdWsStart]) != Character.DIRECTIONALITY_WHITESPACE) {
                    return ++cdWsStart;
                }
            }
        }

        return startPos;
    }

    private TextLineComponent[] makeComponentsOnRange(int startPos,
                                                      int limitPos) {

        // sigh I really hate to do this here since it's part of the
        // bidi algorithm.
        // cdWsStart is the start of the trailing counterdirectional
        // whitespace
        final int cdWsStart = trailingCdWhitespaceStart(startPos, limitPos);

        int tlcIndex;
        int tlcStart = fComponentStart;

        for (tlcIndex = 0; tlcIndex < fComponents.length; tlcIndex++) {
            int gaLimit = tlcStart + fComponents[tlcIndex].getNumCharacters();
            if (gaLimit > startPos) {
                break;
            }
            else {
                tlcStart = gaLimit;
            }
        }

        // tlcStart is now the start of the tlc at tlcIndex

        int componentCount;
        {
            boolean split = false;
            int compStart = tlcStart;
            int lim=tlcIndex;
            for (boolean cont=true; cont; lim++) {
                int gaLimit = compStart + fComponents[lim].getNumCharacters();
                if (cdWsStart > Math.max(compStart, startPos)
                            && cdWsStart < Math.min(gaLimit, limitPos)) {
                    split = true;
                }
                if (gaLimit >= limitPos) {
                    cont=false;
                }
                else {
                    compStart = gaLimit;
                }
            }
            componentCount = lim-tlcIndex;
            if (split) {
                componentCount++;
            }
        }

        TextLineComponent[] components = new TextLineComponent[componentCount];
        int newCompIndex = 0;
        int linePos = startPos;

        int breakPt = cdWsStart;

        int subsetFlag;
        if (breakPt == startPos) {
            subsetFlag = fIsDirectionLTR? TextLineComponent.LEFT_TO_RIGHT :
                                          TextLineComponent.RIGHT_TO_LEFT;
            breakPt = limitPos;
        }
        else {
            subsetFlag = TextLineComponent.UNCHANGED;
        }

        while (linePos < limitPos) {

            int compLength = fComponents[tlcIndex].getNumCharacters();
            int tlcLimit = tlcStart + compLength;

            int start = Math.max(linePos, tlcStart);
            int limit = Math.min(breakPt, tlcLimit);

            components[newCompIndex++] = fComponents[tlcIndex].getSubset(
                                                                start-tlcStart,
                                                                limit-tlcStart,
                                                                subsetFlag);
            linePos += (limit-start);
            if (linePos == breakPt) {
                breakPt = limitPos;
                subsetFlag = fIsDirectionLTR? TextLineComponent.LEFT_TO_RIGHT :
                                              TextLineComponent.RIGHT_TO_LEFT;
            }
            if (linePos == tlcLimit) {
                tlcIndex++;
                tlcStart = tlcLimit;
            }
        }

        return components;
    }

    private TextLine makeTextLineOnRange(int startPos, int limitPos) {

        int[] charsLtoV = null;
        byte[] charLevels = null;

        if (fBidi != null) {
            Bidi lineBidi = fBidi.createLineBidi(startPos, limitPos);
            charLevels = BidiUtils.getLevels(lineBidi);
            int[] charsVtoL = BidiUtils.createVisualToLogicalMap(charLevels);
            charsLtoV = BidiUtils.createInverseMap(charsVtoL);
        }

        TextLineComponent[] components = makeComponentsOnRange(startPos, limitPos);

        return new TextLine(fFrc,
                            components,
                            fBaselineOffsets,
                            fChars,
                            startPos,
                            limitPos,
                            charsLtoV,
                            charLevels,
                            fIsDirectionLTR);

    }

    private void ensureComponents(int start, int limit) {

        if (start < fComponentStart || limit > fComponentLimit) {
            generateComponents(start, limit);
        }
    }

    private void makeLayoutWindow(int localStart) {

        int compStart = localStart;
        int compLimit = fChars.length;

        // If we've already gone past the layout window, format to end of paragraph
        if (layoutCount > 0 && !haveLayoutWindow) {
            float avgLineLength = Math.max(layoutCharCount / layoutCount, 1);
            compLimit = Math.min(localStart + (int)(avgLineLength*EST_LINES), fChars.length);
        }

        if (localStart > 0 || compLimit < fChars.length) {
            if (charIter == null) {
                charIter = new CharArrayIterator(fChars);
            }
            else {
                charIter.reset(fChars);
            }
            if (fLineBreak == null) {
                fLineBreak = BreakIterator.getLineInstance();
            }
            fLineBreak.setText(charIter);
            if (localStart > 0) {
                if (!fLineBreak.isBoundary(localStart)) {
                    compStart = fLineBreak.preceding(localStart);
                }
            }
            if (compLimit < fChars.length) {
                if (!fLineBreak.isBoundary(compLimit)) {
                    compLimit = fLineBreak.following(compLimit);
                }
            }
        }

        ensureComponents(compStart, compLimit);
        haveLayoutWindow = true;
    }

    
Returns the index of the first character which will not fit on on a line beginning at start and possible measuring up to maxAdvance in graphical width. 
Params:
  • start – the character index at which to start measuring. start is an absolute index, not relative to the start of the paragraph
  • maxAdvance – the graphical width in which the line must fit
Throws:
Returns:the index after the last character that will fit on a line beginning at start, which is not longer than maxAdvance in graphical width
/**
     * Returns the index of the first character which will not fit on
     * on a line beginning at {@code start} and possible
     * measuring up to {@code maxAdvance} in graphical width.
     *
     * @param start the character index at which to start measuring.
     *  {@code start} is an absolute index, not relative to the
     *  start of the paragraph
     * @param maxAdvance the graphical width in which the line must fit
     * @return the index after the last character that will fit
     *  on a line beginning at {@code start}, which is not longer
     *  than {@code maxAdvance} in graphical width
     * @throws IllegalArgumentException if {@code start} is
     *          less than the beginning of the paragraph.
     */
    public int getLineBreakIndex(int start, float maxAdvance) {

        int localStart = start - fStart;

        if (!haveLayoutWindow ||
                localStart < fComponentStart ||
                localStart >= fComponentLimit) {
            makeLayoutWindow(localStart);
        }

        return calcLineBreak(localStart, maxAdvance) + fStart;
    }

    
Returns the graphical width of a line beginning at start and including characters up to limit. start and limit are absolute indices, not relative to the start of the paragraph. 
Params:
  • start – the character index at which to start measuring
  • limit – the character index at which to stop measuring
Throws:
Returns:the graphical width of a line beginning at start and including characters up to limit
/**
     * Returns the graphical width of a line beginning at {@code start}
     * and including characters up to {@code limit}.
     * {@code start} and {@code limit} are absolute indices,
     * not relative to the start of the paragraph.
     *
     * @param start the character index at which to start measuring
     * @param limit the character index at which to stop measuring
     * @return the graphical width of a line beginning at {@code start}
     *   and including characters up to {@code limit}
     * @throws IndexOutOfBoundsException if {@code limit} is less
     *         than {@code start}
     * @throws IllegalArgumentException if {@code start} or
     *          {@code limit} is not between the beginning of
     *          the paragraph and the end of the paragraph.
     */
    public float getAdvanceBetween(int start, int limit) {

        int localStart = start - fStart;
        int localLimit = limit - fStart;

        ensureComponents(localStart, localLimit);
        TextLine line = makeTextLineOnRange(localStart, localLimit);
        return line.getMetrics().advance;
        // could cache line in case getLayout is called with same start, limit
    }

    
Returns a TextLayout on the given character range. 
Params:
  • start – the index of the first character
  • limit – the index after the last character. Must be greater than start
Throws:
Returns:a TextLayout for the characters beginning at start up to (but not including) limit
/**
     * Returns a {@code TextLayout} on the given character range.
     *
     * @param start the index of the first character
     * @param limit the index after the last character.  Must be greater
     *   than {@code start}
     * @return a {@code TextLayout} for the characters beginning at
     *  {@code start} up to (but not including) {@code limit}
     * @throws IndexOutOfBoundsException if {@code limit} is less
     *         than {@code start}
     * @throws IllegalArgumentException if {@code start} or
     *          {@code limit} is not between the beginning of
     *          the paragraph and the end of the paragraph.
     */
    public TextLayout getLayout(int start, int limit) {

        int localStart = start - fStart;
        int localLimit = limit - fStart;

        ensureComponents(localStart, localLimit);
        TextLine textLine = makeTextLineOnRange(localStart, localLimit);

        if (localLimit < fChars.length) {
            layoutCharCount += limit-start;
            layoutCount++;
        }

        return new TextLayout(textLine,
                              fBaseline,
                              fBaselineOffsets,
                              fJustifyRatio);
    }

    private int formattedChars = 0;
    private static boolean wantStats = false;/*"true".equals(System.getProperty("collectStats"));*/
    private boolean collectStats = false;

    private void printStats() {
        System.out.println("formattedChars: " + formattedChars);
        //formattedChars = 0;
        collectStats = false;
    }

    
Updates the TextMeasurer after a single character has been inserted into the paragraph currently represented by this TextMeasurer. After this call, this TextMeasurer is equivalent to a new TextMeasurer created from the text; however, it will usually be more efficient to update an existing TextMeasurer than to create a new one from scratch. 
Params:
  • newParagraph – the text of the paragraph after performing
the insertion.  Cannot be null.
  • insertPos – the position in the text where the character was inserted. Must not be less than the start of newParagraph, and must be less than the end of newParagraph.
Throws:
/**
     * Updates the {@code TextMeasurer} after a single character has
     * been inserted
     * into the paragraph currently represented by this
     * {@code TextMeasurer}.  After this call, this
     * {@code TextMeasurer} is equivalent to a new
     * {@code TextMeasurer} created from the text;  however, it will
     * usually be more efficient to update an existing
     * {@code TextMeasurer} than to create a new one from scratch.
     *
     * @param newParagraph the text of the paragraph after performing
     * the insertion.  Cannot be null.
     * @param insertPos the position in the text where the character was
     * inserted.  Must not be less than the start of
     * {@code newParagraph}, and must be less than the end of
     * {@code newParagraph}.
     * @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}
     */
    public void insertChar(AttributedCharacterIterator newParagraph, int insertPos) {

        if (collectStats) {
            printStats();
        }
        if (wantStats) {
            collectStats = true;
        }

        fStart = newParagraph.getBeginIndex();
        int end = newParagraph.getEndIndex();
        if (end - fStart != fChars.length+1) {
            initAll(newParagraph);
        }

        char[] newChars = new char[end-fStart];
        int newCharIndex = insertPos - fStart;
        System.arraycopy(fChars, 0, newChars, 0, newCharIndex);

        char newChar = newParagraph.setIndex(insertPos);
        newChars[newCharIndex] = newChar;
        System.arraycopy(fChars,
                         newCharIndex,
                         newChars,
                         newCharIndex+1,
                         end-insertPos-1);
        fChars = newChars;

        if (fBidi != null || Bidi.requiresBidi(newChars, newCharIndex, newCharIndex + 1) ||
                newParagraph.getAttribute(TextAttribute.BIDI_EMBEDDING) != null) {

            fBidi = new Bidi(newParagraph);
            if (fBidi.isLeftToRight()) {
                fBidi = null;
            }
        }

        fParagraph = StyledParagraph.insertChar(newParagraph,
                                                fChars,
                                                insertPos,
                                                fParagraph);
        invalidateComponents();
    }

    
Updates the TextMeasurer after a single character has been deleted from the paragraph currently represented by this TextMeasurer. After this call, this TextMeasurer is equivalent to a new TextMeasurer created from the text; however, it will usually be more efficient to update an existing TextMeasurer than to create a new one from scratch. 
Params:
  • newParagraph – the text of the paragraph after performing
the deletion.  Cannot be null.
  • deletePos – the position in the text where the character was removed. Must not be less than the start of newParagraph, and must not be greater than the end of newParagraph.
Throws:
/**
     * Updates the {@code TextMeasurer} after a single character has
     * been deleted
     * from the paragraph currently represented by this
     * {@code TextMeasurer}.  After this call, this
     * {@code TextMeasurer} is equivalent to a new {@code TextMeasurer}
     * created from the text;  however, it will usually be more efficient
     * to update an existing {@code TextMeasurer} than to create a new one
     * from scratch.
     *
     * @param newParagraph the text of the paragraph after performing
     * the deletion.  Cannot be null.
     * @param deletePos the position in the text where the character was removed.
     * Must not be less than
     * the start of {@code newParagraph}, and must not be greater than the
     * end of {@code newParagraph}.
     * @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}
     */
    public void deleteChar(AttributedCharacterIterator newParagraph, int deletePos) {

        fStart = newParagraph.getBeginIndex();
        int end = newParagraph.getEndIndex();
        if (end - fStart != fChars.length-1) {
            initAll(newParagraph);
        }

        char[] newChars = new char[end-fStart];
        int changedIndex = deletePos-fStart;

        System.arraycopy(fChars, 0, newChars, 0, deletePos-fStart);
        System.arraycopy(fChars, changedIndex+1, newChars, changedIndex, end-deletePos);
        fChars = newChars;

        if (fBidi != null) {
            fBidi = new Bidi(newParagraph);
            if (fBidi.isLeftToRight()) {
                fBidi = null;
            }
        }

        fParagraph = StyledParagraph.deleteChar(newParagraph,
                                                fChars,
                                                deletePos,
                                                fParagraph);
        invalidateComponents();
    }

    
NOTE:  This method is only for LineBreakMeasurer's use.  It is package-
private because it returns internal data.

/**
     * NOTE:  This method is only for LineBreakMeasurer's use.  It is package-
     * private because it returns internal data.
     */
    char[] getChars() {

        return fChars;
    }
}