Refactor Styled utility functions into reusable objects.

This takes utility functions from Styled and a few other classes and
incorporates them into two new utility classes, TextLine and
MeasuredText.  The main point of this is to support shaping by skia,
to experiment with how this will look, this also introduces
character-based Arabic shaping.

MeasuredText is used by code that determines line breaks by generating
and examining character widths in logical order.  Factoring the code
in this way makes it usable by the ellipsize functions in TextUtils as
well as by StaticLayout.  This class takes over the caching of widths
and chars arrays that was previously performed by StyledText.  A small
number of MeasuredText objects are themselves cached by the class and
accesed using static obtain and recycle methods.  Generally only these
few cached instances are ever created.

TextLine is used by code that draws or measures text on a line.  This
unifies the line measuring and rendering code, and pushes assumptions
about how rtl text is treated closer to the points where skia code is
invoked.  TextLine implements the functions that were previously
provided by Styled, working on member arrays rather than
explicitly-passed arguments.  It implements the same kind of static
cache as MeasuredText.

TextLine and MeasureText simulate arabic glyph generation and shaping
by using ArabicShaping, ported with very minor changes from ICU4J's
ArabicShaping.  This class generates shaped Arabic glyphs and Lam-Alef
ligatures using Unicode presentation forms.  ArabicShaping is not
intended to be permanent, but to be replaced by real shaping from the
skia layer. It is introduced in order to emulate the behavior of real
shaping so that higher level code dealing with rendering shaped text
and cursor movement over ligatures can be developed and tested; it
also provides basic-level support for Arabic.

Since cursor movement depends on conjuncts whose formation is
font-dependent, cursor movement code that was formerly in Layout and
StaticLayout was moved into TextLine so that it can work on the shaped
text.

Other than these changes, the other major change is a rework of the
ellipsize utility functions to combine multiple branches into fewer
branches with additional state.

Updated copyright notices on new files.

Change-Id: I492cb58b51f5aaf6f14cb1419bdbed49eac5ba29

1 files changed, 92 insertions, 340 deletions

diff --git a/core/java/android/text/StaticLayout.java b/core/java/android/text/StaticLayout.java
index bfa0ab61f3e4..0c6c545dfb46 100644
--- a/core/java/android/text/StaticLayout.java
+++ b/core/java/android/text/StaticLayout.java
@@ -23,8 +23,6 @@ import android.graphics.Paint;
 import android.text.style.LeadingMarginSpan;
 import android.text.style.LineHeightSpan;
 import android.text.style.MetricAffectingSpan;
-import android.text.style.ReplacementSpan;
-import android.util.Log;
 
 /**
  * StaticLayout is a Layout for text that will not be edited after it
@@ -96,13 +94,13 @@ extends Layout
         mLineDirections = new Directions[
                              ArrayUtils.idealIntArraySize(2 * mColumns)];
 
+        mMeasured = MeasuredText.obtain();
+
         generate(source, bufstart, bufend, paint, outerwidth, align,
                  spacingmult, spacingadd, includepad, includepad,
                  ellipsize != null, ellipsizedWidth, ellipsize);
 
-        mChdirs = null;
-        mChs = null;
-        mWidths = null;
+        mMeasured = MeasuredText.recycle(mMeasured);
         mFontMetricsInt = null;
     }
 
@@ -113,6 +111,7 @@ extends Layout
         mLines = new int[ArrayUtils.idealIntArraySize(2 * mColumns)];
         mLineDirections = new Directions[
                              ArrayUtils.idealIntArraySize(2 * mColumns)];
+        mMeasured = MeasuredText.obtain();
     }
 
     /* package */ void generate(CharSequence source, int bufstart, int bufend,
@@ -130,38 +129,22 @@ extends Layout
         Paint.FontMetricsInt fm = mFontMetricsInt;
         int[] choosehtv = null;
 
-        int end = TextUtils.indexOf(source, '\n', bufstart, bufend);
-        int bufsiz = end >= 0 ? end - bufstart : bufend - bufstart;
-        boolean first = true;
-
-        if (mChdirs == null) {
-            mChdirs = new byte[ArrayUtils.idealByteArraySize(bufsiz + 1)];
-            mChs = new char[ArrayUtils.idealCharArraySize(bufsiz + 1)];
-            mWidths = new float[ArrayUtils.idealIntArraySize((bufsiz + 1) * 2)];
-        }
-
-        byte[] chdirs = mChdirs;
-        char[] chs = mChs;
-        float[] widths = mWidths;
+        MeasuredText measured = mMeasured;
 
-        AlteredCharSequence alter = null;
         Spanned spanned = null;
-
         if (source instanceof Spanned)
             spanned = (Spanned) source;
 
         int DEFAULT_DIR = DIR_LEFT_TO_RIGHT; // XXX
 
-        for (int start = bufstart; start <= bufend; start = end) {
-            if (first)
-                first = false;
-            else
-                end = TextUtils.indexOf(source, '\n', start, bufend);
-
-            if (end < 0)
-                end = bufend;
+        int paraEnd;
+        for (int paraStart = bufstart; paraStart <= bufend; paraStart = paraEnd) {
+            paraEnd = TextUtils.indexOf(source, '\n', paraStart, bufend);
+            if (paraEnd < 0)
+                paraEnd = bufend;
             else
-                end++;
+                paraEnd++;
+            int paraLen = paraEnd - paraStart;
 
             int firstWidthLineCount = 1;
             int firstwidth = outerwidth;
@@ -170,19 +153,20 @@ extends Layout
             LineHeightSpan[] chooseht = null;
 
             if (spanned != null) {
-                LeadingMarginSpan[] sp;
-
-                sp = spanned.getSpans(start, end, LeadingMarginSpan.class);
+                LeadingMarginSpan[] sp = spanned.getSpans(paraStart, paraEnd,
+                        LeadingMarginSpan.class);
                 for (int i = 0; i < sp.length; i++) {
                     LeadingMarginSpan lms = sp[i];
                     firstwidth -= sp[i].getLeadingMargin(true);
                     restwidth -= sp[i].getLeadingMargin(false);
                     if (lms instanceof LeadingMarginSpan.LeadingMarginSpan2) {
-                        firstWidthLineCount = ((LeadingMarginSpan.LeadingMarginSpan2)lms).getLeadingMarginLineCount();
+                        firstWidthLineCount =
+                            ((LeadingMarginSpan.LeadingMarginSpan2)lms)
+                            .getLeadingMarginLineCount();
                     }
                 }
 
-                chooseht = spanned.getSpans(start, end, LineHeightSpan.class);
+                chooseht = spanned.getSpans(paraStart, paraEnd, LineHeightSpan.class);
 
                 if (chooseht.length != 0) {
                     if (choosehtv == null ||
@@ -194,7 +178,7 @@ extends Layout
                     for (int i = 0; i < chooseht.length; i++) {
                         int o = spanned.getSpanStart(chooseht[i]);
 
-                        if (o < start) {
+                        if (o < paraStart) {
                             // starts in this layout, before the
                             // current paragraph
 
@@ -208,135 +192,48 @@ extends Layout
                 }
             }
 
-            if (end - start > chdirs.length) {
-                chdirs = new byte[ArrayUtils.idealByteArraySize(end - start)];
-                mChdirs = chdirs;
-            }
-            if (end - start > chs.length) {
-                chs = new char[ArrayUtils.idealCharArraySize(end - start)];
-                mChs = chs;
-            }
-            if ((end - start) * 2 > widths.length) {
-                widths = new float[ArrayUtils.idealIntArraySize((end - start) * 2)];
-                mWidths = widths;
-            }
-
-            TextUtils.getChars(source, start, end, chs, 0);
-            final int n = end - start;
-
-            boolean easy = true;
-            boolean altered = false;
-            int dir = DEFAULT_DIR; // XXX pass value in
-
-            for (int i = 0; i < n; i++) {
-                if (chs[i] >= FIRST_RIGHT_TO_LEFT) {
-                    easy = false;
-                    break;
-                }
-            }
-
-            // Ensure that none of the underlying characters are treated
-            // as viable breakpoints, and that the entire run gets the
-            // same bidi direction.
-
-            if (source instanceof Spanned) {
-                Spanned sp = (Spanned) source;
-                ReplacementSpan[] spans = sp.getSpans(start, end, ReplacementSpan.class);
-
-                for (int y = 0; y < spans.length; y++) {
-                    int a = sp.getSpanStart(spans[y]);
-                    int b = sp.getSpanEnd(spans[y]);
-
-                    for (int x = a; x < b; x++) {
-                        chs[x - start] = '\uFFFC';
-                    }
-                }
-            }
-
-            if (!easy) {
-                // XXX put override flags, etc. into chdirs
-                // XXX supply dir rather than force
-                dir = AndroidBidi.bidi(DIR_REQUEST_DEFAULT_LTR, chs, chdirs, n, false);
-
-                // Do mirroring for right-to-left segments
-
-                for (int i = 0; i < n; i++) {
-                    if (chdirs[i] == Character.DIRECTIONALITY_RIGHT_TO_LEFT) {
-                        int j;
-
-                        for (j = i; j < n; j++) {
-                            if (chdirs[j] !=
-                                Character.DIRECTIONALITY_RIGHT_TO_LEFT)
-                                break;
-                        }
-
-                        if (AndroidCharacter.mirror(chs, i, j - i))
-                            altered = true;
-
-                        i = j - 1;
-                    }
-                }
-            }
-
-            CharSequence sub;
+            measured.setPara(source, paraStart, paraEnd, DIR_REQUEST_DEFAULT_LTR);
+            char[] chs = measured.mChars;
+            float[] widths = measured.mWidths;
+            byte[] chdirs = measured.mLevels;
+            int dir = measured.mDir;
+            boolean easy = measured.mEasy;
 
-            if (altered) {
-                if (alter == null)
-                    alter = AlteredCharSequence.make(source, chs, start, end);
-                else
-                    alter.update(chs, start, end);
-
-                sub = alter;
-            } else {
-                sub = source;
-            }
+            CharSequence sub = source;
 
             int width = firstwidth;
 
             float w = 0;
-            int here = start;
+            int here = paraStart;
 
-            int ok = start;
+            int ok = paraStart;
             float okwidth = w;
             int okascent = 0, okdescent = 0, oktop = 0, okbottom = 0;
 
-            int fit = start;
+            int fit = paraStart;
             float fitwidth = w;
             int fitascent = 0, fitdescent = 0, fittop = 0, fitbottom = 0;
 
             boolean tab = false;
 
-            int next;
-            for (int i = start; i < end; i = next) {
+            int spanEnd;
+            for (int spanStart = paraStart; spanStart < paraEnd; spanStart = spanEnd) {
                 if (spanned == null)
-                    next = end;
+                    spanEnd = paraEnd;
                 else
-                    next = spanned.nextSpanTransition(i, end,
-                                                      MetricAffectingSpan.
-                                                      class);
+                    spanEnd = spanned.nextSpanTransition(spanStart, paraEnd,
+                            MetricAffectingSpan.class);
 
-                if (spanned == null) {
-                    paint.getTextWidths(sub, i, next, widths);
-                    System.arraycopy(widths, 0, widths,
-                                     end - start + (i - start), next - i);
+                int spanLen = spanEnd - spanStart;
+                int startInPara = spanStart - paraStart;
+                int endInPara = spanEnd - paraStart;
 
-                    paint.getFontMetricsInt(fm);
+                if (spanned == null) {
+                    measured.addStyleRun(paint, spanLen, fm);
                 } else {
-                    mWorkPaint.baselineShift = 0;
-
-                    Styled.getTextWidths(paint, mWorkPaint,
-                                         spanned, i, next,
-                                         widths, fm);
-                    System.arraycopy(widths, 0, widths,
-                                     end - start + (i - start), next - i);
-
-                    if (mWorkPaint.baselineShift < 0) {
-                        fm.ascent += mWorkPaint.baselineShift;
-                        fm.top += mWorkPaint.baselineShift;
-                    } else {
-                        fm.descent += mWorkPaint.baselineShift;
-                        fm.bottom += mWorkPaint.baselineShift;
-                    }
+                    MetricAffectingSpan[] spans =
+                        spanned.getSpans(spanStart, spanEnd, MetricAffectingSpan.class);
+                    measured.addStyleRun(paint, spans, spanLen, fm);
                 }
 
                 int fmtop = fm.top;
@@ -344,27 +241,17 @@ extends Layout
                 int fmascent = fm.ascent;
                 int fmdescent = fm.descent;
 
-                if (false) {
-                    StringBuilder sb = new StringBuilder();
-                    for (int j = i; j < next; j++) {
-                        sb.append(widths[j - start + (end - start)]);
-                        sb.append(' ');
-                    }
-
-                    Log.e("text", sb.toString());
-                }
-
-                for (int j = i; j < next; j++) {
-                    char c = chs[j - start];
+                for (int j = spanStart; j < spanEnd; j++) {
+                    char c = chs[j - paraStart];
                     float before = w;
 
                     if (c == '\n') {
                         ;
                     } else if (c == '\t') {
-                        w = Layout.nextTab(sub, start, end, w, null);
+                        w = Layout.nextTab(sub, paraStart, paraEnd, w, null);
                         tab = true;
-                    } else if (c >= 0xD800 && c <= 0xDFFF && j + 1 < next) {
-                        int emoji = Character.codePointAt(chs, j - start);
+                    } else if (c >= 0xD800 && c <= 0xDFFF && j + 1 < spanEnd) {
+                        int emoji = Character.codePointAt(chs, j - paraStart);
 
                         if (emoji >= MIN_EMOJI && emoji <= MAX_EMOJI) {
                             Bitmap bm = EMOJI_FACTORY.
@@ -387,13 +274,13 @@ extends Layout
                                 tab = true;
                                 j++;
                             } else {
-                                w += widths[j - start + (end - start)];
+                                w += widths[j - paraStart];
                             }
                         } else {
-                            w += widths[j - start + (end - start)];
+                            w += widths[j - paraStart];
                         }
                     } else {
-                        w += widths[j - start + (end - start)];
+                        w += widths[j - paraStart];
                     }
 
                     // Log.e("text", "was " + before + " now " + w + " after " + c + " within " + width);
@@ -429,12 +316,12 @@ extends Layout
 
                         if (c == ' ' || c == '\t' ||
                             ((c == '.'  || c == ',' || c == ':' || c == ';') &&
-                             (j - 1 < here || !Character.isDigit(chs[j - 1 - start])) &&
-                             (j + 1 >= next || !Character.isDigit(chs[j + 1 - start]))) ||
+                             (j - 1 < here || !Character.isDigit(chs[j - 1 - paraStart])) &&
+                             (j + 1 >= spanEnd || !Character.isDigit(chs[j + 1 - paraStart]))) ||
                             ((c == '/' || c == '-') &&
-                             (j + 1 >= next || !Character.isDigit(chs[j + 1 - start]))) ||
+                             (j + 1 >= spanEnd || !Character.isDigit(chs[j + 1 - paraStart]))) ||
                             (c >= FIRST_CJK && isIdeographic(c, true) &&
-                             j + 1 < next && isIdeographic(chs[j + 1 - start], false))) {
+                             j + 1 < spanEnd && isIdeographic(chs[j + 1 - paraStart], false))) {
                             okwidth = w;
                             ok = j + 1;
 
@@ -451,7 +338,7 @@ extends Layout
                         if (ok != here) {
                             // Log.e("text", "output ok " + here + " to " +ok);
 
-                            while (ok < next && chs[ok - start] == ' ') {
+                            while (ok < spanEnd && chs[ok - paraStart] == ' ') {
                                 ok++;
                             }
 
@@ -461,9 +348,9 @@ extends Layout
                                     v,
                                     spacingmult, spacingadd, chooseht,
                                     choosehtv, fm, tab,
-                                    needMultiply, start, chdirs, dir, easy,
+                                    needMultiply, paraStart, chdirs, dir, easy,
                                     ok == bufend, includepad, trackpad,
-                                    widths, start, end - start,
+                                    chs, widths, here - paraStart,
                                     where, ellipsizedWidth, okwidth,
                                     paint);
 
@@ -487,7 +374,7 @@ extends Layout
                         if (ok != here) {
                             // Log.e("text", "output ok " + here + " to " +ok);
 
-                            while (ok < next && chs[ok - start] == ' ') {
+                            while (ok < spanEnd && chs[ok - paraStart] == ' ') {
                                 ok++;
                             }
 
@@ -497,9 +384,9 @@ extends Layout
                                     v,
                                     spacingmult, spacingadd, chooseht,
                                     choosehtv, fm, tab,
-                                    needMultiply, start, chdirs, dir, easy,
+                                    needMultiply, paraStart, chdirs, dir, easy,
                                     ok == bufend, includepad, trackpad,
-                                    widths, start, end - start,
+                                    chs, widths, here - paraStart,
                                     where, ellipsizedWidth, okwidth,
                                     paint);
 
@@ -513,18 +400,19 @@ extends Layout
                                     v,
                                     spacingmult, spacingadd, chooseht,
                                     choosehtv, fm, tab,
-                                    needMultiply, start, chdirs, dir, easy,
+                                    needMultiply, paraStart, chdirs, dir, easy,
                                     fit == bufend, includepad, trackpad,
-                                    widths, start, end - start,
+                                    chs, widths, here - paraStart,
                                     where, ellipsizedWidth, fitwidth,
                                     paint);
 
                             here = fit;
                         } else {
                             // Log.e("text", "output one " + here + " to " +(here + 1));
-                            measureText(paint, mWorkPaint,
-                                        source, here, here + 1, fm, tab,
-                                        null);
+                            // XXX not sure why the existing fm wasn't ok.
+                            // measureText(paint, mWorkPaint,
+                            //             source, here, here + 1, fm, tab,
+                            //             null);
 
                             v = out(source,
                                     here, here+1,
@@ -533,18 +421,18 @@ extends Layout
                                     v,
                                     spacingmult, spacingadd, chooseht,
                                     choosehtv, fm, tab,
-                                    needMultiply, start, chdirs, dir, easy,
+                                    needMultiply, paraStart, chdirs, dir, easy,
                                     here + 1 == bufend, includepad,
                                     trackpad,
-                                    widths, start, end - start,
+                                    chs, widths, here - paraStart,
                                     where, ellipsizedWidth,
-                                    widths[here - start], paint);
+                                    widths[here - paraStart], paint);
 
                             here = here + 1;
                         }
 
-                        if (here < i) {
-                            j = next = here; // must remeasure
+                        if (here < spanStart) {
+                            j = spanEnd = here; // must remeasure
                         } else {
                             j = here - 1;    // continue looping
                         }
@@ -561,7 +449,7 @@ extends Layout
                 }
             }
 
-            if (end != here) {
+            if (paraEnd != here) {
                 if ((fittop | fitbottom | fitdescent | fitascent) == 0) {
                     paint.getFontMetricsInt(fm);
 
@@ -574,20 +462,20 @@ extends Layout
                 // Log.e("text", "output rest " + here + " to " + end);
 
                 v = out(source,
-                        here, end, fitascent, fitdescent,
+                        here, paraEnd, fitascent, fitdescent,
                         fittop, fitbottom,
                         v,
                         spacingmult, spacingadd, chooseht,
                         choosehtv, fm, tab,
-                        needMultiply, start, chdirs, dir, easy,
-                        end == bufend, includepad, trackpad,
-                        widths, start, end - start,
+                        needMultiply, paraStart, chdirs, dir, easy,
+                        paraEnd == bufend, includepad, trackpad,
+                        chs, widths, here - paraStart,
                         where, ellipsizedWidth, w, paint);
             }
 
-            start = end;
+            paraStart = paraEnd;
 
-            if (end == bufend)
+            if (paraEnd == bufend)
                 break;
         }
 
@@ -602,9 +490,9 @@ extends Layout
                     v,
                     spacingmult, spacingadd, null,
                     null, fm, false,
-                    needMultiply, bufend, chdirs, DEFAULT_DIR, true,
+                    needMultiply, bufend, null, DEFAULT_DIR, true,
                     true, includepad, trackpad,
-                    widths, bufstart, 0,
+                    null, null, bufstart,
                     where, ellipsizedWidth, 0, paint);
         }
     }
@@ -714,28 +602,6 @@ extends Layout
     }
 */
 
-    private static int getFit(TextPaint paint,
-                              TextPaint workPaint,
-                       CharSequence text, int start, int end,
-                       float wid) {
-        int high = end + 1, low = start - 1, guess;
-
-        while (high - low > 1) {
-            guess = (high + low) / 2;
-
-            if (measureText(paint, workPaint,
-                            text, start, guess, null, true, null) > wid)
-                high = guess;
-            else
-                low = guess;
-        }
-
-        if (low < start)
-            return start;
-        else
-            return low;
-    }
-
     private int out(CharSequence text, int start, int end,
                       int above, int below, int top, int bottom, int v,
                       float spacingmult, float spacingadd,
@@ -744,7 +610,7 @@ extends Layout
                       boolean needMultiply, int pstart, byte[] chdirs,
                       int dir, boolean easy, boolean last,
                       boolean includepad, boolean trackpad,
-                      float[] widths, int widstart, int widoff,
+                      char[] chs, float[] widths, int widstart,
                       TextUtils.TruncateAt ellipsize, float ellipsiswidth,
                       float textwidth, TextPaint paint) {
         int j = mLineCount;
@@ -752,8 +618,6 @@ extends Layout
         int want = off + mColumns + TOP;
         int[] lines = mLines;
 
-        // Log.e("text", "line " + start + " to " + end + (last ? "===" : ""));
-
         if (want >= lines.length) {
             int nlen = ArrayUtils.idealIntArraySize(want + 1);
             int[] grow = new int[nlen];
@@ -840,122 +704,12 @@ extends Layout
         if (easy) {
             mLineDirections[j] = linedirs;
         } else {
-            int startOff = start - pstart;
-            int baseLevel = dir == DIR_LEFT_TO_RIGHT ? 0 : 1;
-            int curLevel = chdirs[startOff];
-            int minLevel = curLevel;
-            int runCount = 1;
-            for (int i = start + 1; i < end; ++i) {
-                int level = chdirs[i - pstart];
-                if (level != curLevel) {
-                    curLevel = level;
-                    ++runCount;
-                }
-            }
-
-            // add final run for trailing counter-directional whitespace
-            int visEnd = end;
-            if ((curLevel & 1) != (baseLevel & 1)) {
-                // look for visible end
-                while (--visEnd >= start) {
-                    char ch = text.charAt(visEnd);
-
-                    if (ch == '\n') {
-                        --visEnd;
-                        break;
-                    }
-
-                    if (ch != ' ' && ch != '\t') {
-                        break;
-                    }
-                }
-                ++visEnd;
-                if (visEnd != end) {
-                    ++runCount;
-                }
-            }
-
-            if (runCount == 1 && minLevel == baseLevel) {
-                if ((minLevel & 1) != 0) {
-                    linedirs = DIRS_ALL_RIGHT_TO_LEFT;
-                }
-                // we're done, only one run on this line
-            } else {
-                int[] ld = new int[runCount * 2];
-                int maxLevel = minLevel;
-                int levelBits = minLevel << RUN_LEVEL_SHIFT;
-                {
-                    // Start of first pair is always 0, we write
-                    // length then start at each new run, and the
-                    // last run length after we're done.
-                    int n = 1;
-                    int prev = start;
-                    curLevel = minLevel;
-                    for (int i = start; i < visEnd; ++i) {
-                        int level = chdirs[i - pstart];
-                        if (level != curLevel) {
-                            curLevel = level;
-                            if (level > maxLevel) {
-                                maxLevel = level;
-                            } else if (level < minLevel) {
-                                minLevel = level;
-                            }
-                            // XXX ignore run length limit of 2^RUN_LEVEL_SHIFT
-                            ld[n++] = (i - prev) | levelBits;
-                            ld[n++] = i - start;
-                            levelBits = curLevel << RUN_LEVEL_SHIFT;
-                            prev = i;
-                        }
-                    }
-                    ld[n] = (visEnd - prev) | levelBits;
-                    if (visEnd < end) {
-                        ld[++n] = visEnd - start;
-                        ld[++n] = (end - visEnd) | (baseLevel << RUN_LEVEL_SHIFT);
-                    }
-                }
-
-                // See if we need to swap any runs.
-                // If the min level run direction doesn't match the base
-                // direction, we always need to swap (at this point
-                // we have more than one run).
-                // Otherwise, we don't need to swap the lowest level.
-                // Since there are no logically adjacent runs at the same
-                // level, if the max level is the same as the (new) min
-                // level, we have a series of alternating levels that
-                // is already in order, so there's no more to do.
-                //
-                boolean swap;
-                if ((minLevel & 1) == baseLevel) {
-                    minLevel += 1;
-                    swap = maxLevel > minLevel;
-                } else {
-                    swap = runCount > 1;
-                }
-                if (swap) {
-                    for (int level = maxLevel - 1; level >= minLevel; --level) {
-                        for (int i = 0; i < ld.length; i += 2) {
-                            if (chdirs[startOff + ld[i]] >= level) {
-                                int e = i + 2;
-                                while (e < ld.length && chdirs[startOff + ld[e]] >= level) {
-                                    e += 2;
-                                }
-                                for (int low = i, hi = e - 2; low < hi; low += 2, hi -= 2) {
-                                    int x = ld[low]; ld[low] = ld[hi]; ld[hi] = x;
-                                    x = ld[low+1]; ld[low+1] = ld[hi+1]; ld[hi+1] = x;
-                                }
-                                i = e + 2;
-                            }
-                        }
-                    }
-                }
-                linedirs = new Directions(ld);
-            }
-
-            mLineDirections[j] = linedirs;
+            mLineDirections[j] = AndroidBidi.directions(dir, chdirs, widstart, chs,
+                    widstart, end - start);
 
             // If ellipsize is in marquee mode, do not apply ellipsis on the first line
             if (ellipsize != null && (ellipsize != TextUtils.TruncateAt.MARQUEE || j != 0)) {
-                calculateEllipsis(start, end, widths, widstart, widoff,
+                calculateEllipsis(start, end, widths, widstart,
                                   ellipsiswidth, ellipsize, j,
                                   textwidth, paint);
             }
@@ -966,7 +720,7 @@ extends Layout
     }
 
     private void calculateEllipsis(int linestart, int lineend,
-                                   float[] widths, int widstart, int widoff,
+                                   float[] widths, int widstart,
                                    float avail, TextUtils.TruncateAt where,
                                    int line, float textwidth, TextPaint paint) {
         int len = lineend - linestart;
@@ -986,7 +740,7 @@ extends Layout
             int i;
 
             for (i = len; i >= 0; i--) {
-                float w = widths[i - 1 + linestart - widstart + widoff];
+                float w = widths[i - 1 + linestart - widstart];
 
                 if (w + sum + ellipsiswid > avail) {
                     break;
@@ -1002,7 +756,7 @@ extends Layout
             int i;
 
             for (i = 0; i < len; i++) {
-                float w = widths[i + linestart - widstart + widoff];
+                float w = widths[i + linestart - widstart];
 
                 if (w + sum + ellipsiswid > avail) {
                     break;
@@ -1019,7 +773,7 @@ extends Layout
 
             float ravail = (avail - ellipsiswid) / 2;
             for (right = len; right >= 0; right--) {
-                float w = widths[right - 1 + linestart - widstart + widoff];
+                float w = widths[right - 1 + linestart - widstart];
 
                 if (w + rsum > ravail) {
                     break;
@@ -1030,7 +784,7 @@ extends Layout
 
             float lavail = avail - ellipsiswid - rsum;
             for (left = 0; left < right; left++) {
-                float w = widths[left + linestart - widstart + widoff];
+                float w = widths[left + linestart - widstart];
 
                 if (w + lsum > lavail) {
                     break;
@@ -1047,7 +801,7 @@ extends Layout
         mLines[mColumns * line + ELLIPSIS_COUNT] = ellipsisCount;
     }
 
-    // Override the baseclass so we can directly access our members,
+    // Override the base class so we can directly access our members,
     // rather than relying on member functions.
     // The logic mirrors that of Layout.getLineForVertical
     // FIXME: It may be faster to do a linear search for layouts without many lines.
@@ -1156,10 +910,8 @@ extends Layout
     private static final char FIRST_RIGHT_TO_LEFT = '\u0590';
 
     /*
-     * These are reused across calls to generate()
+     * This is reused across calls to generate()
      */
-    private byte[] mChdirs;
-    private char[] mChs;
-    private float[] mWidths;
+    private MeasuredText mMeasured;
     private Paint.FontMetricsInt mFontMetricsInt = new Paint.FontMetricsInt();
 }