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/*

   Licensed to the Apache Software Foundation (ASF) under one or more
   contributor license agreements.  See the NOTICE file distributed with
   this work for additional information regarding copyright ownership.
   The ASF licenses this file to You under the Apache License, Version 2.0
   (the "License"); you may not use this file except in compliance with
   the License.  You may obtain a copy of the License at

       http://www.apache.org/licenses/LICENSE-2.0

   Unless required by applicable law or agreed to in writing, software
   distributed under the License is distributed on an "AS IS" BASIS,
   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   See the License for the specific language governing permissions and
   limitations under the License.

 */
package org.apache.batik.bridge;

import java.awt.BasicStroke;
import java.awt.Graphics2D;
import java.awt.Shape;
import java.awt.Stroke;
import java.awt.font.FontRenderContext;
import java.awt.font.TextAttribute;
import java.awt.geom.AffineTransform;
import java.awt.geom.Area;
import java.awt.geom.GeneralPath;
import java.awt.geom.PathIterator;
import java.awt.geom.Point2D;
import java.awt.geom.Rectangle2D;
import java.awt.geom.Line2D;
import java.text.AttributedCharacterIterator;
import java.text.CharacterIterator;
import java.util.HashSet;
import java.util.Set;

import org.apache.batik.gvt.font.AWTGVTFont;
import org.apache.batik.gvt.font.AltGlyphHandler;
import org.apache.batik.gvt.font.GVTFont;
import org.apache.batik.gvt.font.GVTGlyphMetrics;
import org.apache.batik.gvt.font.GVTGlyphVector;
import org.apache.batik.gvt.font.GVTLineMetrics;
import org.apache.batik.gvt.text.ArabicTextHandler;
import org.apache.batik.gvt.text.GVTAttributedCharacterIterator;
import org.apache.batik.gvt.text.TextPath;

/**
 * Implementation of TextSpanLayout which uses java.awt.font.GlyphVector.
 * @see org.apache.batik.bridge.TextSpanLayout
 *
 * @author Bill Haneman
 * @version $Id$
 */
public class GlyphLayout implements TextSpanLayout {

    protected GVTGlyphVector gv;
    private GVTFont font;
    private GVTLineMetrics metrics;
    private AttributedCharacterIterator aci;
    protected Point2D advance;
    private Point2D offset;
    private float   xScale=1;
    private float   yScale=1;
    private TextPath textPath;
    private Point2D textPathAdvance;
    private int []  charMap;
    private boolean vertical, adjSpacing=true;
    private float [] glyphAdvances;
    private boolean isAltGlyph; //false

    // When layoutApplied is false it means that the glyph positions
    // are different from where they would be if you did
    // doExplicitGlyphLayout().
    protected boolean layoutApplied = false;
    // When spacingApplied is false it means that xScale, yScale and
    // kerning/wordspacing stuff haven't been applied. This can
    // be rectified by calling adjustTextSpacing().  Note that when
    // spacing is actually used layoutApplied will be cleared it
    // is not garunteed that applying text spacing will cause it to
    // be cleared (it will only be cleared if the glyphs move).
    private boolean spacingApplied = false;
    // When pathApplied is false it means that the text has not been
    // layed out on the associated text path (if any).  If there is an
    // associated text path then this will clear both layoutApplied
    // and spacing applied but neither will be touched if no text path
    // is present.
    private boolean pathApplied    = false;


    public static final AttributedCharacterIterator.Attribute FLOW_LINE_BREAK
        = GVTAttributedCharacterIterator.TextAttribute.FLOW_LINE_BREAK;

    public static final AttributedCharacterIterator.Attribute FLOW_PARAGRAPH
        = GVTAttributedCharacterIterator.TextAttribute.FLOW_PARAGRAPH;

    public static final AttributedCharacterIterator.Attribute
        FLOW_EMPTY_PARAGRAPH
        = GVTAttributedCharacterIterator.TextAttribute.FLOW_EMPTY_PARAGRAPH;

    public static final AttributedCharacterIterator.Attribute LINE_HEIGHT
        = GVTAttributedCharacterIterator.TextAttribute.LINE_HEIGHT;

    public static final AttributedCharacterIterator.Attribute
        VERTICAL_ORIENTATION
        = GVTAttributedCharacterIterator.TextAttribute.VERTICAL_ORIENTATION;

    public static final
        AttributedCharacterIterator.Attribute VERTICAL_ORIENTATION_ANGLE =
       GVTAttributedCharacterIterator.TextAttribute.VERTICAL_ORIENTATION_ANGLE;

    public static final
        AttributedCharacterIterator.Attribute HORIZONTAL_ORIENTATION_ANGLE =
     GVTAttributedCharacterIterator.TextAttribute.HORIZONTAL_ORIENTATION_ANGLE;

    private static final AttributedCharacterIterator.Attribute X
        = GVTAttributedCharacterIterator.TextAttribute.X;

    private static final AttributedCharacterIterator.Attribute Y
        = GVTAttributedCharacterIterator.TextAttribute.Y;

    private static final AttributedCharacterIterator.Attribute DX
        = GVTAttributedCharacterIterator.TextAttribute.DX;

    private static final AttributedCharacterIterator.Attribute DY
        = GVTAttributedCharacterIterator.TextAttribute.DY;

    private static final AttributedCharacterIterator.Attribute ROTATION
        = GVTAttributedCharacterIterator.TextAttribute.ROTATION;

    private static final AttributedCharacterIterator.Attribute BASELINE_SHIFT
        = GVTAttributedCharacterIterator.TextAttribute.BASELINE_SHIFT;

    private static final AttributedCharacterIterator.Attribute WRITING_MODE
        = GVTAttributedCharacterIterator.TextAttribute.WRITING_MODE;

    private static final Integer WRITING_MODE_TTB
        = GVTAttributedCharacterIterator.TextAttribute.WRITING_MODE_TTB;

    private static final Integer ORIENTATION_AUTO
        = GVTAttributedCharacterIterator.TextAttribute.ORIENTATION_AUTO;

    public static final AttributedCharacterIterator.Attribute GVT_FONT
        = GVTAttributedCharacterIterator.TextAttribute.GVT_FONT;

    protected static Set runAtts = new HashSet();

    static {
        runAtts.add(X);
        runAtts.add(Y);
        runAtts.add(DX);
        runAtts.add(DY);
        runAtts.add(ROTATION);
        runAtts.add(BASELINE_SHIFT);
    }

    protected static Set szAtts = new HashSet();

    static {
        szAtts.add(TextAttribute.SIZE);
        szAtts.add(GVT_FONT);
        szAtts.add(LINE_HEIGHT);
    }


    /**
     * Creates the specified text layout using the
     * specified AttributedCharacterIterator and rendering context.
     *
     * @param aci the AttributedCharacterIterator whose text is to
     *  be laid out
     * @param charMap Indicates how chars in aci map to original
     *                text char array.
     * @param offset The offset position of this text layout
     * @param frc the FontRenderContext to use for generating glyphs.
     */
    public GlyphLayout(AttributedCharacterIterator aci,
                       int [] charMap,
                       Point2D offset,
                       FontRenderContext frc) {

        this.aci = aci;
        this.offset = offset;
        this.font = getFont();
        this.charMap = charMap;

        this.metrics = font.getLineMetrics
            (aci, aci.getBeginIndex(), aci.getEndIndex(), frc);

        // create the glyph vector
        this.gv = null;
        this.aci.first();
        this.vertical = (aci.getAttribute(WRITING_MODE) == WRITING_MODE_TTB);
        this.textPath =  (TextPath) aci.getAttribute
            (GVTAttributedCharacterIterator.TextAttribute.TEXTPATH);

        AltGlyphHandler altGlyphHandler
            = (AltGlyphHandler)this.aci.getAttribute
            (GVTAttributedCharacterIterator.TextAttribute.ALT_GLYPH_HANDLER);
        if (altGlyphHandler != null) {
            // this must be an altGlyph text element, try and create
            // the alternate glyphs
            this.gv = altGlyphHandler.createGlyphVector
                (frc, this.font.getSize(), this.aci);
            if ( this.gv != null ){
                this.isAltGlyph = true;
            }
        }
        if (this.gv == null) {
            // either not an altGlyph or the altGlyphHandler failed to
            // create a glyph vector
            this.gv = font.createGlyphVector(frc, this.aci);
        }
    }


    public GVTGlyphVector getGlyphVector() {
        return this.gv;
    }


    /**
     * Returns the current text position at the beginning
     * of glyph layout, before the application of explicit
     * glyph positioning attributes.
     */
    public Point2D getOffset() {
        return offset;
    }

    /**
     * Sets the scaling factor to use for string.  if ajdSpacing is
     * true then only the spacing between glyphs will be adjusted
     * otherwise the glyphs and the spaces between them will be
     * adjusted.  Only the scale factor in the progression direction
     * is used (x for horizontal text, y for vertical text
     * ).
     * @param xScale Scale factor to apply in X direction.
     * @param yScale Scale factor to apply in Y direction.
     * @param adjSpacing True if only spaces should be adjusted.
     */
    public void setScale(float xScale, float yScale, boolean adjSpacing) {
        // Fix the off axis scale factor.
        if (vertical) xScale = 1;
        else          yScale = 1;

        if ((xScale != this.xScale) ||
            (yScale != this.yScale) ||
            (adjSpacing != this.adjSpacing)) {
            this.xScale = xScale;
            this.yScale = yScale;
            this.adjSpacing = adjSpacing;

            // We don't affect layoutApplied directly...

            // However if we did path layout or spacing it's all junk now...
            spacingApplied = false;
            glyphAdvances  = null;
            pathApplied    = false;
        }
    }

    /**
     * Sets the text position used for the implicit origin
     * of glyph layout. Ignored if multiple explicit glyph
     * positioning attributes are present in ACI
     * (e.g. if the aci has multiple X or Y values).
     */
    public void setOffset(Point2D offset) {
        if ((offset.getX() != this.offset.getX()) ||
            (offset.getY() != this.offset.getY())) {
            if ((layoutApplied)||(spacingApplied)) {
                // Already layed out need to shift glyph positions to
                // account for new offset.
                float dx = (float)(offset.getX()-this.offset.getX());
                float dy = (float)(offset.getY()-this.offset.getY());
                int numGlyphs = gv.getNumGlyphs();

                float [] gp = gv.getGlyphPositions(0, numGlyphs+1, null);
                Point2D.Float pos = new Point2D.Float();
                for (int i=0; i<=numGlyphs; i++) {
                    pos.x = gp[2*i  ]+dx;
                    pos.y = gp[2*i+1]+dy;
                    gv.setGlyphPosition(i, pos);
                }
            }

            // When not layed out (or after updating) just set the new
            // offset this will be factored in for any future layout
            // operations.
            this.offset = offset;

            // We don't affect layoutApplied or spacingApplied since
            // they both work off the offset value.

            // However if we did path layout it's all junk now...
            pathApplied = false;
        }
    }

    public GVTGlyphMetrics getGlyphMetrics(int glyphIndex) {
        return gv.getGlyphMetrics(glyphIndex);
    }

    public GVTLineMetrics getLineMetrics() {
        return metrics;
    }

    /**
     * Returns true if the advance direction of this text is vertical.
     */
    public boolean isVertical() {
        return vertical;
    }

    /**
     * Returns true if this layout in on a text path.
     */
    public boolean isOnATextPath() {
        return (textPath != null);
    }


    /**
     * Returns the number of glyphs in this layout.
     */
    public int getGlyphCount() {
        return gv.getNumGlyphs();
    }


    /**
     * Returns the number of chars represented by the glyphs within the
     * specified range.
     *
     * @param startGlyphIndex The index of the first glyph in the range.
     * @param endGlyphIndex The index of the last glyph in the range.
     *
     * @return The number of chars.
     */
    public int getCharacterCount(int startGlyphIndex, int endGlyphIndex) {
        return gv.getCharacterCount(startGlyphIndex, endGlyphIndex);
    }

    /**
     * Returns true if the text direction in this layout is from left to right.
     */
    public boolean isLeftToRight() {
        aci.first();
        int bidiLevel =
                (Integer) aci.getAttribute
                        (GVTAttributedCharacterIterator.TextAttribute.BIDI_LEVEL);

        // Check if low bit is set if not then we are left to right
        // (even bidi level).
        return ((bidiLevel&0x01) == 0);
    }


    /**
     * This method makes certain that the layout has been
     * completed at this point (much of the layout is done lazily).
     */
    private final void syncLayout() {
        if (!pathApplied) {
            doPathLayout();
        }
    }

    /**
     * Paints the text layout using the
     * specified Graphics2D and rendering context.
     * @param g2d the Graphics2D to use
     */
    public void draw(Graphics2D g2d) {
        syncLayout();
        gv.draw(g2d, aci);
    }

    /**
     * Returns the current text position at the completion
     * of glyph layout.
     */
    public Point2D getAdvance2D() {
        adjustTextSpacing();
        return advance;
    }


    /**
     * Returns the outline of the completed glyph layout.
     */
    public Shape getOutline() {
        syncLayout();

        return gv.getOutline();
    }

    public float [] getGlyphAdvances() {
        if (glyphAdvances != null)
            return glyphAdvances;

        if (!spacingApplied)
            // This will layout the text if needed.
            adjustTextSpacing();

        int numGlyphs = gv.getNumGlyphs();
        float [] glyphPos = gv.getGlyphPositions(0, numGlyphs+1, null);
        glyphAdvances = new float[numGlyphs+1];
        int off = 0;
        if (isVertical())
            off = 1;

        float start = glyphPos[off];
        for (int i=0; iDECORATION_UNDERLINE | DECORATION_STRIKETHROUGH
     */
    public Shape getDecorationOutline(int decorationType) {
        syncLayout();

        Shape g = new GeneralPath();
        if ((decorationType & DECORATION_UNDERLINE) != 0) {
             ((GeneralPath) g).append(getUnderlineShape(), false);
        }
        if ((decorationType & DECORATION_STRIKETHROUGH) != 0) {
             ((GeneralPath) g).append(getStrikethroughShape(), false);
        }
        if ((decorationType & DECORATION_OVERLINE) != 0) {
             ((GeneralPath) g).append(getOverlineShape(), false);
        }
        return g;
    }

    /**
     * Returns the rectangular bounds of the completed glyph layout.
     */
    public Rectangle2D getBounds2D() {
        syncLayout();
        return gv.getBounds2D(aci);
    }

    /**
     * Returns the rectangular bounds of the completed glyph layout,
     * inclusive of "decoration" (underline, overline, etc.)
     */
    public Rectangle2D getGeometricBounds() {
        syncLayout();
        Rectangle2D gvB, decB;
        gvB = gv.getGeometricBounds();
        decB = getDecorationOutline(DECORATION_ALL).getBounds2D();
        return gvB.createUnion(decB);
    }

    /**
     * Returns the position to used when drawing a text run after this one.
     * It takes into account the text path layout if there is one.
     */
    public Point2D getTextPathAdvance() {
        syncLayout();
        if (textPath != null) {
            return textPathAdvance;
        } else {
            return getAdvance2D();
        }
    }


    /**
     * Returns the index of the first glyph that has the specified char index.
     *
     * @param charIndex The original index of the character in the text node's
     * text string.
     * @return The index of the matching glyph in this layout's glyph vector,
     *         or -1 if a matching glyph could not be found.
     */
    public int getGlyphIndex(int charIndex) {
        int numGlyphs = getGlyphCount();
        int j=0;
        for (int i = 0; i < numGlyphs; i++) {
            int count = getCharacterCount(i, i);
            for (int n=0; n= charMap.length)
                    return -1;
            }
        }
        return -1;
    }

    /**
     * Returns the index of the last glyph that has the specified char index.
     *
     * @param charIndex The original index of the character in the text node's
     * text string.
     * @return The index of the matching glyph in this layout's glyph vector,
     *         or -1 if a matching glyph could not be found.
     */
    public int getLastGlyphIndex(int charIndex) {
        int numGlyphs = getGlyphCount();
        int j=charMap.length-1;
        for (int i = numGlyphs-1; i >= 0; --i) {
            int count = getCharacterCount(i, i);
            for (int n=0; n endCharIndex) {
            int temp = beginCharIndex;
            beginCharIndex = endCharIndex;
            endCharIndex = temp;
        }
        GeneralPath shape = null;
        int numGlyphs = getGlyphCount();

        Point2D.Float [] topPts = new Point2D.Float[2*numGlyphs];
        Point2D.Float [] botPts = new Point2D.Float[2*numGlyphs];

        int ptIdx = 0;

        int currentChar = 0;
        for (int i = 0; i < numGlyphs; i++) {
            int glyphCharIndex = charMap[currentChar];
            if ((glyphCharIndex >= beginCharIndex) &&
                (glyphCharIndex <= endCharIndex) &&
                gv.isGlyphVisible(i)) {

                Shape gbounds = gv.getGlyphLogicalBounds(i);
                if (gbounds != null) {
                    // We got something...
                    if (shape == null)
                        shape = new GeneralPath();

                    // We are pretty dumb here we assume that we always
                    // get back polygons with four sides to them if
                    // isn't met we are SOL.
                    float [] pts = new float[6];
                    int count = 0;
                    int type = -1;

                    PathIterator pi = gbounds.getPathIterator(null);
                    Point2D.Float firstPt = null;

                    while (!pi.isDone()) {
                        type = pi.currentSegment(pts);
                        if ((type == PathIterator.SEG_MOVETO) ||
                            (type == PathIterator.SEG_LINETO)) {
                            // LINETO or MOVETO
                            if (count > 4) break; // too many lines...
                            if (count == 4) {
                                // make sure we are just closing it..
                                if ((firstPt == null)     ||
                                    (firstPt.x != pts[0]) ||
                                    (firstPt.y != pts[1]))
                                    break;
                            } else {
                                Point2D.Float pt;
                                pt = new Point2D.Float(pts[0], pts[1]);
                                if (count == 0) firstPt = pt;
                                // Use sides of  rectangle...
                                switch (count) {
                                case 0: botPts[ptIdx]   = pt; break;
                                case 1: topPts[ptIdx]   = pt; break;
                                case 2: topPts[ptIdx+1] = pt; break;
                                case 3: botPts[ptIdx+1] = pt; break;
                                }
                            }
                        } else if (type == PathIterator.SEG_CLOSE) {
                                // Close in the wrong spot?
                            if ((count < 4) || (count > 5)) break;
                        } else {
                            // QUADTO or CUBETO
                            break;
                        }

                        count++;
                        pi.next();
                    }
                    if (pi.isDone()) {
                        // Sucessfully Expressed as a quadralateral...
                        if ((botPts[ptIdx]!=null) &&
                            ((topPts[ptIdx].x != topPts[ptIdx+1].x) ||
                             (topPts[ptIdx].y != topPts[ptIdx+1].y)))
                            // box isn't empty so use it's points...
                            ptIdx += 2;
                    } else {
                        // Wasn't a quadralateral so just add it don't try
                        // and merge it...
                        addPtsToPath(shape, topPts, botPts, ptIdx);
                        ptIdx = 0;
                        shape.append(gbounds, false);
                    }
                }
            }
            currentChar += getCharacterCount(i, i);
            if (currentChar >= charMap.length)
                currentChar = charMap.length-1;
        }
        addPtsToPath(shape, topPts, botPts, ptIdx);

        return shape;
    }

    public static final double eps = 0.00001;

    public static boolean epsEQ(double a, double b) {
        return ((a+eps > b) && (a-eps < b));
    }

    public static int makeConvexHull(Point2D.Float [] pts, int numPts) {
        // Sort the Pts in X...
        Point2D.Float tmp;
        for (int i=1; i= 2) {
                    pt0 = botList[nBotPts-2];
                    pt1 = botList[nBotPts-1];
                    float dx = pt1.x-pt0.x;
                    float dy = pt1.y-pt0.y;
                    float c0 = dy*pt0.x-dx*pt0.y;
                    soln = dx*pt.y-dy*pt.x+c0;
                    if (soln > eps) // Left turn add and we are done..
                        break;
                    if (soln > -eps) {
                        // On line take lowest Y of two and keep going
                        if (pt1.y < pt.y) pt = pt1;
                        nBotPts--;
                        break;
                    }
                    // right turn drop prev pt;
                    nBotPts--;
                }
                botList[nBotPts++] = pt;
            } else {
                // Above line goes into top pt list...
                while (nTopPts >= 2) {
                    pt0 = topList[nTopPts-2];
                    pt1 = topList[nTopPts-1];
                    float dx = pt1.x-pt0.x;
                    float dy = pt1.y-pt0.y;
                    float c0 = dy*pt0.x-dx*pt0.y;
                    soln = dx*pt.y-dy*pt.x+c0;
                    if (soln < -eps) // Right turn add and check next point.
                        break;
                    if (soln < eps) {
                        // On line take greatest Y of two and keep going
                        if (pt1.y > pt.y) pt = pt1;
                        nTopPts--;
                        break;
                    }
                    // left turn drop prev pt;
                    nTopPts--;
                }
                topList[nTopPts++] = pt;
            }
        }

        // Check last point in both sets...
        Point2D.Float pt = pts[numPts-1];
        while (nBotPts >= 2) {
            pt0 = botList[nBotPts-2];
            pt1 = botList[nBotPts-1];
            float dx = pt1.x-pt0.x;
            float dy = pt1.y-pt0.y;
            float c0 = dy*pt0.x-dx*pt0.y;
            soln = dx*pt.y-dy*pt.x+c0;
            if (soln > eps)
                // Left turn add and we are done..
                break;
            if (soln > -eps) {
                // On line take lowest Y of two and keep going
                if (pt1.y >= pt.y) nBotPts--;
                break;
            }
            // right turn drop prev pt;
            nBotPts--;
        }

        while (nTopPts >= 2) {
            pt0 = topList[nTopPts-2];
            pt1 = topList[nTopPts-1];
            float dx = pt1.x-pt0.x;
            float dy = pt1.y-pt0.y;
            float c0 = dy*pt0.x-dx*pt0.y;
            soln = dx*pt.y-dy*pt.x+c0;
            if (soln < -eps)
                // Right turn done...
                break;
            if (soln < eps) {
                // On line take lowest Y of two and keep going
                if (pt1.y <= pt.y) nTopPts--;
                break;
            }
            // left turn drop prev pt;
            nTopPts--;
        }

        System.arraycopy( topList, 0, pts, 0, nTopPts );
        int i= nTopPts;

        // We always include the 'last' point as it is always on convex hull.
        pts[i++] = pts[numPts-1];

        // don't include botList[0] since it is the same as topList[0].
        for (int n=nBotPts-1; n>0; n--, i++)
            pts[i] = botList[n];

        return i;
    }

    public static void addPtsToPath(GeneralPath shape,
                                     Point2D.Float [] topPts,
                                     Point2D.Float [] botPts,
                                     int numPts) {
        if (numPts < 2) return;
        if (numPts == 2) {
            shape.moveTo(topPts[0].x, topPts[0].y);
            shape.lineTo(topPts[1].x, topPts[1].y);
            shape.lineTo(botPts[1].x, botPts[1].y);
            shape.lineTo(botPts[0].x, botPts[0].y);
            shape.lineTo(topPts[0].x, topPts[0].y);
            return;
        }

        // Here we 'connect the dots' the best way we know how...
        // What I do is construct a convex hull between adjacent
        // character boxes, then I union that into the shape.  this
        // does a good job of bridging between adjacent characters,
        // but still closely tracking to text boxes.  The use of the
        // Area class is fairly heavy weight but it seems to keep up
        // in this instanace (probably because all the shapes are very
        // simple polygons).
        Point2D.Float [] boxes = new Point2D.Float[8];
        Point2D.Float [] chull = new Point2D.Float[8];
        boxes[4] = topPts[0];
        boxes[5] = topPts[1];
        boxes[6] = botPts[1];
        boxes[7] = botPts[0];
        Area []areas = new Area[numPts/2];
        int nAreas =0;
        for (int i=2; i 1) {
            int n=0;
            for (int i=1; i (gbounds2d.getX()+(gbounds2d.getWidth()/2d)));
                    boolean isLeadingEdge = !isRightHalf;
                    int charIndex = charMap[currentChar];
                    textHit = new TextHit(charIndex, isLeadingEdge);
                    return textHit;
                }
            }
            currentChar += getCharacterCount(i, i);
            if (currentChar >= charMap.length)
                currentChar = charMap.length-1;
        }
        return textHit;
    }

//protected

    /**
     * Returns the GVTFont to use when rendering the specified
     * character iterator.  This should already be set as an attribute
     * on the aci.
     *
     * @return The GVTFont to use.
     */
    protected GVTFont getFont() {
        aci.first();
        GVTFont gvtFont = (GVTFont)aci.getAttribute(GVT_FONT);

        if (gvtFont != null)
            return gvtFont;

        // shouldn't get here
        return new AWTGVTFont(aci.getAttributes());
    }

    /**
     * Returns a shape describing the overline decoration for a given ACI.
     */
    protected Shape getOverlineShape() {
        double y = metrics.getOverlineOffset();
        float overlineThickness = metrics.getOverlineThickness();

        // need to move the overline a bit lower,
        // not sure if this is correct behaviour or not
        y += overlineThickness;

        // Not certain what should be done here...
        aci.first();
        Float dy = (Float) aci.getAttribute(DY);
        if (dy != null)
            y += dy;

        Stroke overlineStroke =
            new BasicStroke(overlineThickness);
        Rectangle2D logicalBounds = gv.getLogicalBounds();

        return overlineStroke.createStrokedShape(
                           new Line2D.Double(
                           logicalBounds.getMinX() + overlineThickness/2.0, offset.getY()+y,
                           logicalBounds.getMaxX() - overlineThickness/2.0, offset.getY()+y));
    }

    /**
     * Returns a shape describing the undeline decoration for a given ACI.
     */
    protected Shape getUnderlineShape() {

        double y = metrics.getUnderlineOffset();
        float underlineThickness = metrics.getUnderlineThickness();

        // need to move the underline a bit lower,
        // not sure if this is correct behaviour or not
        y += underlineThickness*1.5;

        BasicStroke underlineStroke =
            new BasicStroke(underlineThickness);

        // Not certain what should be done here...
        aci.first();
        Float dy = (Float) aci.getAttribute(DY);
        if (dy != null)
            y += dy;

        Rectangle2D logicalBounds = gv.getLogicalBounds();

        return underlineStroke.createStrokedShape(
                           new Line2D.Double(
                           logicalBounds.getMinX() + underlineThickness/2.0, offset.getY()+y,
                           logicalBounds.getMaxX() - underlineThickness/2.0, offset.getY()+y));
    }

    /**
     * Returns a shape describing the strikethrough line for a given ACI.
     */
    protected Shape getStrikethroughShape() {
        double y = metrics.getStrikethroughOffset();
        float strikethroughThickness = metrics.getStrikethroughThickness();

        Stroke strikethroughStroke =
            new BasicStroke(strikethroughThickness);

        // Not certain what should be done here...
        aci.first();
        Float dy = (Float) aci.getAttribute(DY);
        if (dy != null)
            y += dy;

        Rectangle2D logicalBounds = gv.getLogicalBounds();
        return strikethroughStroke.createStrokedShape(
                           new Line2D.Double(
                           logicalBounds.getMinX() + strikethroughThickness/2.0, offset.getY()+y,
                           logicalBounds.getMaxX() - strikethroughThickness/2.0, offset.getY()+y));
    }

    /**
     * Explicitly lays out each of the glyphs in the glyph
     * vector. This will handle any glyph position adjustments such as
     * dx, dy and baseline offsets.  It will also handle vertical
     * layouts.
     */
    protected void doExplicitGlyphLayout() {

        this.gv.performDefaultLayout();

        float baselineAscent
            = vertical ?
            (float) gv.getLogicalBounds().getWidth() :
            (metrics.getAscent() + Math.abs(metrics.getDescent()));

        int numGlyphs = gv.getNumGlyphs();

        float[] gp = gv.getGlyphPositions(0, numGlyphs+1, null);
        float verticalFirstOffset = 0f;
        float horizontalFirstOffset = 0f;

        boolean glyphOrientationAuto = isGlyphOrientationAuto();
        int glyphOrientationAngle = 0;
        if (!glyphOrientationAuto) {
            glyphOrientationAngle = getGlyphOrientationAngle();
        }
        int i=0;
        int aciStart = aci.getBeginIndex();
        int aciIndex = 0;
        char ch = aci.first();
        int runLimit = aciIndex+aciStart;

        Float x=null, y=null, dx=null, dy=null, rotation=null;
        Object baseline=null;

        float shift_x_pos = 0;
        float shift_y_pos = 0;
        float curr_x_pos = (float)offset.getX();
        float curr_y_pos = (float)offset.getY();

        Point2D.Float pos = new Point2D.Float();
        boolean hasArabicTransparent = false;

        while (i < numGlyphs) {
            if (aciIndex+aciStart >= runLimit) {
                runLimit = aci.getRunLimit(runAtts);
                x        = (Float) aci.getAttribute(X);
                y        = (Float) aci.getAttribute(Y);
                dx       = (Float) aci.getAttribute(DX);
                dy       = (Float) aci.getAttribute(DY);
                rotation = (Float) aci.getAttribute(ROTATION);
                baseline = aci.getAttribute(BASELINE_SHIFT);
            }

            GVTGlyphMetrics gm = gv.getGlyphMetrics(i);

            if (i==0) {
                if (isVertical()) {
                    if (glyphOrientationAuto) {
                        if (isLatinChar(ch)) {
                            // it will be rotated 90
                            verticalFirstOffset = 0f;
                        } else {
                            // it won't be rotated
                            float advY = gm.getVerticalAdvance();
                            float asc  = metrics.getAscent();
                            float dsc  = metrics.getDescent();
                            verticalFirstOffset =  asc+(advY-(asc+dsc))/2;
                        }
                    } else {
                        if (glyphOrientationAngle == 0) {
                            float advY = gm.getVerticalAdvance();
                            float asc  = metrics.getAscent();
                            float dsc  = metrics.getDescent();
                            verticalFirstOffset =  asc+(advY-(asc+dsc))/2;
                        } else {
                            // 90, 180, 270
                            verticalFirstOffset = 0f;
                        }
                    }
                } else {  // not vertical
                    if ((glyphOrientationAngle == 270)) {
                        horizontalFirstOffset =
                            (float)gm.getBounds2D().getHeight();
                    } else {
                        // 0, 90, 180
                        horizontalFirstOffset = 0;
                    }
                }
            } else {  // not the first char
                if (glyphOrientationAuto        &&
                    (verticalFirstOffset == 0f) && !isLatinChar(ch)) {
                    float advY = gm.getVerticalAdvance();
                    float asc  = metrics.getAscent();
                    float dsc  = metrics.getDescent();
                    verticalFirstOffset =  asc + (advY - (asc+dsc))/2;
                }
            }

            // ox and oy are origin adjustments for each glyph,
            // computed on the basis of baseline-shifts, etc.
            float ox = 0f;
            float oy = 0f;
            float glyphOrientationRotation = 0f;
            float glyphRotation = 0f;

            if (ch != CharacterIterator.DONE) {
                if (vertical) {
                    if (glyphOrientationAuto) {
                        if (isLatinChar(ch)) {
                            // If character is Latin, then rotate by
                            // 90 degrees
                            glyphOrientationRotation = (float) (Math.PI / 2f);
                        } else {
                            glyphOrientationRotation = 0f;
                        }
                    } else {
                        glyphOrientationRotation = (float)Math.toRadians(glyphOrientationAngle);
                    }
                    if (textPath != null) {
                        // if vertical and on a path, any x's are ignored
                        x = null;
                    }
                } else {
                    glyphOrientationRotation = (float)Math.toRadians(glyphOrientationAngle);
                    if (textPath != null) {
                        // if horizontal and on a path, any y's are ignored
                        y = null;
                    }
                }

                // calculate the total rotation for this glyph
                if (rotation == null || rotation.isNaN()) {
                    glyphRotation = glyphOrientationRotation;
                } else {
                    glyphRotation = (rotation +
                                     glyphOrientationRotation);
                }

                if ((x != null) && !x.isNaN()) {
                    if (i == 0)
                        shift_x_pos = (float)(x -offset.getX());
                    curr_x_pos = x -shift_x_pos;
                }
                if (dx != null && !dx.isNaN()) {
                    curr_x_pos += dx;
                }

                if ((y != null) && !y.isNaN()) {
                    if (i == 0)
                        shift_y_pos = (float)(y -offset.getY());
                    curr_y_pos = y -shift_y_pos;
                }
                if (dy != null && !dy.isNaN()) {
                    curr_y_pos += dy;
                } else if (i > 0) {
                    curr_y_pos += gp[i*2 + 1]-gp[i*2 - 1];
                }

                float baselineAdjust = 0f;
                if (baseline != null) {
                    if (baseline instanceof Integer) {
                        if (baseline==TextAttribute.SUPERSCRIPT_SUPER) {
                            baselineAdjust = baselineAscent*0.5f;
                        } else if (baseline==TextAttribute.SUPERSCRIPT_SUB) {
                            baselineAdjust = -baselineAscent*0.5f;
                        }
                    } else if (baseline instanceof Float) {
                        baselineAdjust = (Float) baseline;
                    }
                    if (vertical) {
                        ox = baselineAdjust;
                    } else {
                        oy = -baselineAdjust;
                    }
                }

                if (vertical) {
                    // offset due to rotation of first character
                    oy += verticalFirstOffset;

                    if (glyphOrientationAuto) {
                        if (isLatinChar(ch)) {
                            ox += metrics.getStrikethroughOffset();
                        } else {
                            Rectangle2D glyphBounds
                                = gv.getGlyphVisualBounds(i).getBounds2D();
                            ox -= (float)((glyphBounds.getMaxX() - gp[2*i]) -
                                          glyphBounds.getWidth()/2);
                        }
                    } else {
                        // center the character if it's not auto orient
                        Rectangle2D glyphBounds
                            = gv.getGlyphVisualBounds(i).getBounds2D();
                        if (glyphOrientationAngle == 0) {
                            ox -= (float)((glyphBounds.getMaxX() - gp[2*i]) -
                                          glyphBounds.getWidth()/2);
                        } else if (glyphOrientationAngle == 180) {
                            ox += (float)((glyphBounds.getMaxX() - gp[2*i]) -
                                          glyphBounds.getWidth()/2);
                        } else if (glyphOrientationAngle == 90) {
                            ox += metrics.getStrikethroughOffset();
                        } else { // 270
                            ox -= metrics.getStrikethroughOffset();
                        }
                    }
                } else {
                    ox += horizontalFirstOffset;
                    if (glyphOrientationAngle == 90) {
                        oy -= gm.getHorizontalAdvance();
                    } else if (glyphOrientationAngle == 180) {
                        oy -= metrics.getAscent();
                    }
                }
            }

            // set the new glyph position
            pos.x = curr_x_pos+ox;
            pos.y = curr_y_pos+oy;
            gv.setGlyphPosition(i, pos);

            // calculate the position of the next glyph
            if (ArabicTextHandler.arabicCharTransparent(ch)) {
                hasArabicTransparent = true;
            } else {
                // Apply the advance if the current char is not transparent
                if (vertical) {
                    float advanceY = 0;
                    if (glyphOrientationAuto) {
                        if (isLatinChar(ch)) {
                            advanceY = gm.getHorizontalAdvance();
                        } else {
                            advanceY = gm.getVerticalAdvance();
                        }
                    } else {
                        if ((glyphOrientationAngle ==   0) ||
                            (glyphOrientationAngle == 180)) {
                            advanceY = gm.getVerticalAdvance();
                        } else if (glyphOrientationAngle == 90) {
                            advanceY = gm.getHorizontalAdvance();
                        } else { // 270
                            advanceY = gm.getHorizontalAdvance();
                            // need to translate so that the spacing
                            // between chars is correct
                            gv.setGlyphTransform
                                (i, AffineTransform.getTranslateInstance
                                 (0, advanceY));
                        }
                    }
                    curr_y_pos += advanceY;
                } else {
                    float advanceX = 0;
                    if (glyphOrientationAngle ==   0) {
                        advanceX = gm.getHorizontalAdvance();
                    } else if (glyphOrientationAngle == 180) {
                        advanceX = gm.getHorizontalAdvance();
                        // need to translate so that the spacing
                        // between chars is correct
                        gv.setGlyphTransform
                            (i, AffineTransform.getTranslateInstance
                             (advanceX, 0));
                    } else {
                        // 90, 270
                        advanceX = gm.getVerticalAdvance();
                    }
                    curr_x_pos += advanceX;
                }
            }

            // rotate the glyph
            if (!epsEQ(glyphRotation,0)) {
                AffineTransform glyphTransform = gv.getGlyphTransform(i);
                if (glyphTransform == null) {
                    glyphTransform = new AffineTransform();
                }
                AffineTransform rotAt;
                // Make the 90Deg rotations slightly 'snap to'.
                // Also use explicit matrix to avoid round-off.
                if (epsEQ(glyphRotation, Math.PI/2)) {
                    rotAt = new AffineTransform(0, 1, -1, 0, 0, 0);
                } else if (epsEQ(glyphRotation, Math.PI)) {
                    rotAt = new AffineTransform(-1, 0, 0, -1, 0, 0);
                } else if (epsEQ(glyphRotation, 3*Math.PI/2)) {
                    rotAt = new AffineTransform(0, -1, 1, 0, 0, 0);
                } else {
                    rotAt = AffineTransform.getRotateInstance(glyphRotation);
                }
                glyphTransform.concatenate(rotAt);
                gv.setGlyphTransform(i, glyphTransform);
            }

            aciIndex += gv.getCharacterCount(i,i);
            if (aciIndex >= charMap.length)
                aciIndex = charMap.length-1;
            ch = aci.setIndex(aciIndex+aciStart);
            i++;
        }
        // Update last glyph pos
        pos.x = curr_x_pos;
        pos.y = curr_y_pos;
        gv.setGlyphPosition(i, pos);

        advance = new Point2D.Float((float)(curr_x_pos - offset.getX()),
                                    (float)(curr_y_pos - offset.getY()));


        // Do a last pass positioning the transparent/mark glyphs on the
        // base glyphs.
        if (hasArabicTransparent) {
            ch = aci.first();
            aciIndex = 0;
            i=0;
            int transparentStart = -1;
            while (i < numGlyphs) {
                if (ArabicTextHandler.arabicCharTransparent(ch)) {
                    if (transparentStart == -1) transparentStart = i;
                } else {
                    if (transparentStart != -1) {
                        Point2D         loc   = gv.getGlyphPosition(i);
                        GVTGlyphMetrics gm    = gv.getGlyphMetrics(i);
                        int tyS=0, txS=0;      // these never changed ??     todo
                        float advX=0, advY=0;
                        if (vertical) {
                            if (glyphOrientationAuto ||
                                (glyphOrientationAngle == 90))
                                advY = gm.getHorizontalAdvance();
                            else if (glyphOrientationAngle == 270)
                                advY = 0;
                            else if (glyphOrientationAngle == 0)
                                advX = gm.getHorizontalAdvance();
                            else // 180
                                advX = -gm.getHorizontalAdvance();
                        } else {
                            if (glyphOrientationAngle ==   0)
                                advX = gm.getHorizontalAdvance();
                            else if (glyphOrientationAngle == 90)
                                advY = gm.getHorizontalAdvance();
                            else if (glyphOrientationAngle == 180)
                                advX = 0;
                            else // 270
                                advY = -gm.getHorizontalAdvance();
                        }
                        float baseX = (float)(loc.getX()+advX);
                        float baseY = (float)(loc.getY()+advY);
                        for (int j=transparentStart; j= charMap.length)
                    aciIndex = charMap.length-1;
                ch = aci.setIndex(aciIndex+aciStart);
                i++;
            }

        }


        layoutApplied  = true;
        spacingApplied = false;
        glyphAdvances  = null;
        pathApplied    = false;
    }

    /**
     * Does any spacing adjustments that may have been specified.
     */
    protected void adjustTextSpacing() {

        if (spacingApplied)
            // Nothing to do...
            return;

        if (!layoutApplied)
            // Must have clean layout to do spacing...
            doExplicitGlyphLayout();

        aci.first();
        Boolean customSpacing =  (Boolean) aci.getAttribute(
               GVTAttributedCharacterIterator.TextAttribute.CUSTOM_SPACING);
        if ((customSpacing != null) && customSpacing) {
            advance = doSpacing
                ((Float) aci.getAttribute
                 (GVTAttributedCharacterIterator.TextAttribute.KERNING),
                 (Float) aci.getAttribute
                 (GVTAttributedCharacterIterator.TextAttribute.LETTER_SPACING),
                 (Float) aci.getAttribute
                 (GVTAttributedCharacterIterator.TextAttribute.WORD_SPACING));
            // Basic layout is now messed up...
            layoutApplied  = false;
        }

        // This will clear layoutApplied if it mucks with the current
        // character positions.
        applyStretchTransform(!adjSpacing);

        spacingApplied = true;
        pathApplied    = false;
    }

    /**
     * Performs any spacing adjustments required and returns the new advance
     * value.
     *
     * @param kern The kerning adjustment to apply to the space
     * between each char.
     * @param letterSpacing The amount of spacing required between each char.
     * @param wordSpacing The amount of spacing required between each word.  */
    protected Point2D doSpacing(Float kern,
                                Float letterSpacing,
                                Float wordSpacing) {
        boolean autoKern = true;
        boolean doWordSpacing = false;
        boolean doLetterSpacing = false;
        float kernVal = 0f;
        float letterSpacingVal = 0f;

        if ((kern != null) && (!kern.isNaN())) {
            kernVal = kern;
            autoKern = false;
        }
        if ((letterSpacing != null) && (!letterSpacing.isNaN())) {
            letterSpacingVal = letterSpacing;
            doLetterSpacing = true;
        }
        if ((wordSpacing != null) && (!wordSpacing.isNaN())) {
            doWordSpacing = true;
        }

        int numGlyphs = gv.getNumGlyphs();

        float dx = 0f;
        float dy = 0f;
        Point2D[] newPositions = new Point2D[numGlyphs+1];
        Point2D prevPos = gv.getGlyphPosition(0);
        int prevCode    = gv.getGlyphCode(0);
        float x = (float) prevPos.getX();
        float y = (float) prevPos.getY();

        Point2D lastCharAdvance
            = new Point2D.Double(advance.getX() - (gv.getGlyphPosition(numGlyphs-1).getX() - x),
                                 advance.getY() - (gv.getGlyphPosition(numGlyphs-1).getY() - y));

        try {
            GVTFont font = gv.getFont();
            // do letter spacing first
            if ((numGlyphs > 1) && (doLetterSpacing || !autoKern)) {
                for (int i=1; i<=numGlyphs; ++i) {
                    Point2D gpos = gv.getGlyphPosition(i);
                    int     currCode;
                    currCode = (i == numGlyphs)?-1:gv.getGlyphCode(i);
                    dx = (float)gpos.getX()-(float)prevPos.getX();
                    dy = (float)gpos.getY()-(float)prevPos.getY();
                    if (autoKern) {
                        if (vertical) dy += letterSpacingVal;
                        else          dx += letterSpacingVal;
                    } else {
                        // apply explicit kerning adjustments,
                        // removing any auto-kern values
                        if (vertical) {
                            float vKern = 0;
                            if (currCode != -1)
                                vKern = font.getVKern(prevCode, currCode);
                            dy += kernVal - vKern + letterSpacingVal;
                        } else {
                            float hKern = 0;
                            if (currCode != -1)
                                hKern = font.getHKern(prevCode, currCode);
                            dx += kernVal - hKern + letterSpacingVal;
                        }
                    }
                    x += dx;
                    y += dy;
                    newPositions[i] = new Point2D.Float(x, y);
                    prevPos = gpos;
                    prevCode = currCode;
                }

                for (int i=1; i<=numGlyphs; ++i) { // assign the new positions
                    if (newPositions[i] != null) {
                        gv.setGlyphPosition(i, newPositions[i]);
                    }
                }
            }

             // adjust the advance of the last character
            if (vertical) {
                lastCharAdvance.setLocation
                    (lastCharAdvance.getX(),
                     lastCharAdvance.getY() + kernVal + letterSpacingVal);
            } else {
                lastCharAdvance.setLocation
                    (lastCharAdvance.getX() + kernVal + letterSpacingVal,
                     lastCharAdvance.getY());
            }

            // now do word spacing
            dx = 0f;
            dy = 0f;
            prevPos = gv.getGlyphPosition(0);
            x = (float) prevPos.getX();
            y = (float) prevPos.getY();

            if ((numGlyphs > 1) && (doWordSpacing)) {
                for (int i = 1; i < numGlyphs; i++) {
                    Point2D gpos = gv.getGlyphPosition(i);
                    dx = (float)gpos.getX()-(float)prevPos.getX();
                    dy = (float)gpos.getY()-(float)prevPos.getY();
                    boolean inWS = false;
                    // while this is whitespace, increment
                    int beginWS = i;
                    int endWS = i;
                    GVTGlyphMetrics gm = gv.getGlyphMetrics(i);

                    // BUG: gm.isWhitespace() fails for latin SPACE glyph!
                    while ((gm.getBounds2D().getWidth()<0.01d) || gm.isWhitespace()) {
                        if (!inWS) inWS = true;
                        if (i == numGlyphs-1) {
                            // white space at the end
                            break;
                        }
                        ++i;
                        ++endWS;
                        gpos = gv.getGlyphPosition(i);
                        gm = gv.getGlyphMetrics(i);
                    }

                    if ( inWS ) {  // apply wordSpacing
                        int nWS = endWS-beginWS;
                        float px = (float) prevPos.getX();
                        float py = (float) prevPos.getY();
                        dx = (float) (gpos.getX() - px)/(nWS+1);
                        dy = (float) (gpos.getY() - py)/(nWS+1);
                        if (vertical) {
                            dy += wordSpacing /(nWS+1);
                        } else {
                            dx += wordSpacing /(nWS+1);
                        }
                        for (int j=beginWS; j<=endWS; ++j) {
                            x += dx;
                            y += dy;
                            newPositions[j] = new Point2D.Float(x, y);
                        }
                    } else {
                        dx = (float) (gpos.getX()-prevPos.getX());
                        dy = (float) (gpos.getY()-prevPos.getY());
                        x += dx;
                        y += dy;
                        newPositions[i] = new Point2D.Float(x, y);
                    }
                    prevPos = gpos;
                }
                Point2D gPos = gv.getGlyphPosition(numGlyphs);
                x += (float) (gPos.getX()-prevPos.getX());
                y += (float) (gPos.getY()-prevPos.getY());
                newPositions[numGlyphs] = new Point2D.Float(x, y);

                for (int i=1; i<=numGlyphs; ++i) { // assign the new positions
                    if (newPositions[i] != null) {
                        gv.setGlyphPosition(i, newPositions[i]);
                    }
                }
            }

        } catch (Exception e) {
            e.printStackTrace();
        }

        // calculate the new advance
        double advX = gv.getGlyphPosition(numGlyphs-1).getX()
                     - gv.getGlyphPosition(0).getX();
        double advY = gv.getGlyphPosition(numGlyphs-1).getY()
                     - gv.getGlyphPosition(0).getY();
        Point2D newAdvance = new Point2D.Double(advX + lastCharAdvance.getX(),
                                                advY + lastCharAdvance.getY());
        return newAdvance;
    }

    /**
     * Stretches the text so that it becomes the specified length.
     *
     * @param stretchGlyphs if true xScale, yScale will be applied to
     *                      each glyphs transform.
     */
    protected void applyStretchTransform(boolean stretchGlyphs) {
        if ((xScale == 1) && (yScale==1))
            return;

        AffineTransform scaleAT =
            AffineTransform.getScaleInstance(xScale, yScale);

        int numGlyphs = gv.getNumGlyphs();
        float [] gp   = gv.getGlyphPositions(0, numGlyphs+1, null);

        float initX   = gp[0];
        float initY   = gp[1];
        Point2D.Float pos = new Point2D.Float();
        for (int i = 0; i <= numGlyphs; i++) {
            float dx = gp[2*i]  -initX;
            float dy = gp[2*i+1]-initY;
            pos.x = initX+dx*xScale;
            pos.y = initY+dy*yScale;
            gv.setGlyphPosition(i, pos);

            if ((stretchGlyphs) && (i != numGlyphs)) {
                // stretch the glyph
                AffineTransform glyphTransform = gv.getGlyphTransform(i);
                if (glyphTransform != null) {
                    glyphTransform.preConcatenate(scaleAT);
                    gv.setGlyphTransform(i, glyphTransform);
                } else {
                    gv.setGlyphTransform (i, scaleAT);
                }
            }
        }

        advance = new Point2D.Float((float)(advance.getX()*xScale),
                                    (float)(advance.getY()*yScale));
        // Basic layout is now messed up...
        layoutApplied  = false;
    }

    /**
     * If this layout is on a text path, positions the characters
     * along the path.
     */
    protected void doPathLayout() {
        if (pathApplied)
            return;

        if (!spacingApplied)
            // This will layout the text if needed.
            adjustTextSpacing();

        getGlyphAdvances();

        // if doesn't have an attached text path, just return
        if (textPath == null) {
            // We applied the empty path (i.e. do nothing).
            pathApplied = true;
            return;
        }


        boolean horizontal = !isVertical();

        boolean glyphOrientationAuto = isGlyphOrientationAuto();
        int glyphOrientationAngle = 0;
        if (!glyphOrientationAuto) {
            glyphOrientationAngle = getGlyphOrientationAngle();
        }

        float pathLength  = textPath.lengthOfPath();
        float startOffset = textPath.getStartOffset();
        int   numGlyphs   = gv.getNumGlyphs();

        // make sure all glyphs visible again, this maybe just a change in
        // offset so they may have been made invisible in a previous
        // pathLayout call
        for (int i = 0; i < numGlyphs; i++) {
            gv.setGlyphVisible(i, true);
        }

        // calculate the total length of the glyphs, this will become be
        // the length along the path that is used by the text
        float glyphsLength;
        if (horizontal) {
            glyphsLength = (float) gv.getLogicalBounds().getWidth();
        } else {
            glyphsLength = (float) gv.getLogicalBounds().getHeight();
        }

        // check that pathLength and glyphsLength are not 0
        if (pathLength == 0f || glyphsLength == 0f) {
            // We applied the empty path.
            pathApplied = true;
            textPathAdvance = advance;
            return;
        }

        // the current start point of the character on the path
        // calculate the offset of the first glyph the offset will be
        // 0 if the glyph is on the path (ie. not adjusted by a dy or
        // dx)
        Point2D firstGlyphPosition = gv.getGlyphPosition(0);
        float glyphOffset = 0;   // offset perpendicular to path
        float currentPosition;
        if (horizontal) {
            glyphOffset     = (float)(firstGlyphPosition.getY());
            currentPosition = (float)(firstGlyphPosition.getX() + startOffset);
        } else {
            glyphOffset     = (float)(firstGlyphPosition.getX());
            currentPosition = (float)(firstGlyphPosition.getY() + startOffset);
        }

        char ch = aci.first();
        int start       = aci.getBeginIndex();
        int currentChar = 0;
        int lastGlyphDrawn = -1;
        float lastGlyphAdvance = 0;
        // iterate through the GlyphVector placing each glyph
        for (int i = 0; i < numGlyphs; i++) {

            Point2D currentGlyphPos = gv.getGlyphPosition(i);

            // calculate the advance and offset for the next glyph, do it
            // now before we modify the current glyph position

            float glyphAdvance = 0;  // along path
            float nextGlyphOffset = 0;  // perpendicular to path eg dy or dx
            Point2D nextGlyphPosition = gv.getGlyphPosition(i+1);
            if (horizontal) {
                glyphAdvance    = (float)(nextGlyphPosition.getX() -
                                          currentGlyphPos.getX());
                nextGlyphOffset = (float)(nextGlyphPosition.getY() -
                                          currentGlyphPos.getY());
            } else {
                glyphAdvance    = (float)(nextGlyphPosition.getY() -
                                          currentGlyphPos.getY());
                nextGlyphOffset = (float)(nextGlyphPosition.getX() -
                                          currentGlyphPos.getX());
            }

            // calculate the center line position for the glyph
            Rectangle2D glyphBounds = gv.getGlyphOutline(i).getBounds2D();
            float glyphWidth = (float) glyphBounds.getWidth();
            float glyphHeight = (float) glyphBounds.getHeight();
            float glyphMidX = 0;
            if (glyphWidth > 0) {
                glyphMidX  = (float)(glyphBounds.getX()+glyphWidth/2f);
                glyphMidX -= (float)currentGlyphPos.getX();
            }

            float glyphMidY=0;
            if (glyphHeight > 0) {
                glyphMidY  = (float)(glyphBounds.getY()+glyphHeight/2f);
                glyphMidY -= (float)currentGlyphPos.getY();
            }

            float charMidPos;
            if (horizontal) {
                charMidPos = currentPosition + glyphMidX;
            } else {
                charMidPos = currentPosition + glyphMidY;
            }

            // Calculate the actual point to place the glyph around
            Point2D charMidPoint = textPath.pointAtLength(charMidPos);

            // Check if the glyph is actually on the path
            if (charMidPoint != null) {

                // Calculate the normal to the path (midline of glyph)
                float angle = textPath.angleAtLength(charMidPos);

                // Define the transform of the glyph
                AffineTransform glyphPathTransform = new AffineTransform();

                // rotate midline of glyph to be normal to path
                if (horizontal) {
                    glyphPathTransform.rotate(angle);
                } else {
                    glyphPathTransform.rotate(angle-(Math.PI/2));
                }

                // re-apply any offset eg from tspan, or spacing adjust
                if (horizontal) {
                    glyphPathTransform.translate(0, glyphOffset);
                } else {
                    glyphPathTransform.translate(glyphOffset, 0);
                }

                // translate glyph backwards so we rotate about the
                // center of the glyph
                if (horizontal) {
                    glyphPathTransform.translate(-glyphMidX, 0f);
                } else {
                    glyphPathTransform.translate(0f, -glyphMidY);
                }

                // set the new glyph position and transform
                AffineTransform glyphTransform = gv.getGlyphTransform(i);
                if (glyphTransform != null) {
                    glyphPathTransform.concatenate(glyphTransform);
                }

                gv.setGlyphTransform(i, glyphPathTransform);
                gv.setGlyphPosition (i, charMidPoint);
                // keep track of the last glyph drawn to make calculating the
                // textPathAdvance value easier later
                lastGlyphDrawn = i;
                lastGlyphAdvance = glyphAdvance;

            } else {
                // not on path so don't render
                gv.setGlyphVisible(i, false);
            }
            currentPosition += glyphAdvance;
            glyphOffset += nextGlyphOffset;
            currentChar += gv.getCharacterCount(i,i);
            if (currentChar >= charMap.length)
                currentChar = charMap.length-1;
            ch = aci.setIndex(currentChar+start);
        }

        // store the position where a following glyph should be drawn,
        // note: this will only be used if the following text layout is not
        //       on a text path
        if (lastGlyphDrawn > -1) {
            Point2D lastGlyphPos = gv.getGlyphPosition(lastGlyphDrawn);
            if (horizontal) {
                textPathAdvance = new Point2D.Double
                    (lastGlyphPos.getX()+lastGlyphAdvance,
                     lastGlyphPos.getY());
            } else {
                textPathAdvance = new Point2D.Double
                    (lastGlyphPos.getX(),
                     lastGlyphPos.getY()+lastGlyphAdvance);
            }
        } else {
            textPathAdvance = new Point2D.Double(0,0);
        }

        // The default layout is junk now...
        layoutApplied  = false;
        // The spacing stuff is junk now.
        spacingApplied = false;
        pathApplied    = true;
    }

    /**
     * Returns true if the specified character is within one of the Latin
     * unicode character blocks.
     *
     * @param c The char to test.
     *
     * @return True if c is latin.
     */
    protected boolean isLatinChar(char c) {

        if ( c < 255 && Character.isLetterOrDigit( c )){
            // cheap quick check, should catch most lation-chars
            return true;
        }

        Character.UnicodeBlock block = Character.UnicodeBlock.of(c);

        if (block == Character.UnicodeBlock.BASIC_LATIN ||
            block == Character.UnicodeBlock.LATIN_1_SUPPLEMENT ||
            block == Character.UnicodeBlock.LATIN_EXTENDED_ADDITIONAL ||
            block == Character.UnicodeBlock.LATIN_EXTENDED_A ||
            block == Character.UnicodeBlock.LATIN_EXTENDED_B ||
            block == Character.UnicodeBlock.ARABIC ||
            block == Character.UnicodeBlock.ARABIC_PRESENTATION_FORMS_A ||
            block == Character.UnicodeBlock.ARABIC_PRESENTATION_FORMS_B) {
            return true;
        }
        return false;
    }

    /**
     * Returns whether or not the vertical glyph orientation value is "auto".
     */
    protected boolean isGlyphOrientationAuto() {
        if (!isVertical()) return false;
        aci.first();
        Integer vOrient = (Integer)aci.getAttribute(VERTICAL_ORIENTATION);
        if (vOrient != null) {
            return (vOrient == ORIENTATION_AUTO);
        }
        return true;
    }

    /**
     * Returns the value of the vertical glyph orientation angle. This will be
     * one of 0, 90, 180 or 270.
     */
    protected int getGlyphOrientationAngle() {

        int glyphOrientationAngle = 0;

        aci.first();
        Float angle;

        if (isVertical()) {
            angle = (Float)aci.getAttribute(VERTICAL_ORIENTATION_ANGLE);
        } else {
            angle = (Float)aci.getAttribute(HORIZONTAL_ORIENTATION_ANGLE);
        }

        if (angle != null) {
            glyphOrientationAngle = (int)angle.floatValue();
        }

        // if not one of 0, 90, 180 or 270, round to nearest value
        if ((glyphOrientationAngle !=   0) || (glyphOrientationAngle !=  90) ||       // todo - this logic expression
            (glyphOrientationAngle != 180) || (glyphOrientationAngle != 270)) {       // is true for all values.....

            while (glyphOrientationAngle < 0) {
                glyphOrientationAngle += 360;
            }

            while (glyphOrientationAngle >= 360) {
                glyphOrientationAngle -= 360;
            }

            if ((glyphOrientationAngle <= 45) ||
                (glyphOrientationAngle > 315)) {
                glyphOrientationAngle = 0;
            } else if ((glyphOrientationAngle > 45) &&
                       (glyphOrientationAngle <= 135)) {
                glyphOrientationAngle = 90;
            } else if ((glyphOrientationAngle > 135) &&
                       (glyphOrientationAngle <= 225)) {
                glyphOrientationAngle = 180;
            } else {
                glyphOrientationAngle = 270;
            }
        }
        return glyphOrientationAngle;
    }

    /**
     * Return true is the character index is represented by glyphs
     * in this layout.
     *
     * @param index index of the character in the ACI.
     * @return true if the layout represents that character.
     */
    public boolean hasCharacterIndex(int index){

        for (int aCharMap : charMap) {
            if (index == aCharMap)
                return true;
        }
        return false;
    }

    /**
     * Return true if this text run represents
     * an alt glyph.
     */
    public boolean isAltGlyph(){
        return this.isAltGlyph;
    }

    @Override
    public boolean isReversed(){
        return gv.isReversed();
    }

    @Override
    public void maybeReverse(boolean mirror){
        gv.maybeReverse(mirror);
    }
}