Bug 668204 - Merge nsMathMLmunderFrame and nsMathMLmoverFrame into nsMathMLmunderoverFrame. r=karlt
authorJonathan Hage <hage.jonathan@gmail.com>
Sat, 13 Aug 2011 17:22:12 +0200
changeset 74377 a3adb8c01a197a958e045a4a91ea7fef5deabab8
parent 74376 e99b737739888ad18dfd8be8b862bc97737f5704
child 74378 64b4ec7bfb4300b2ba6127fb22bc21a210db396f
push id2
push userbsmedberg@mozilla.com
push dateFri, 19 Aug 2011 14:38:13 +0000
reviewerskarlt
bugs668204
milestone8.0a1
Bug 668204 - Merge nsMathMLmunderFrame and nsMathMLmoverFrame into nsMathMLmunderoverFrame. r=karlt
layout/base/nsCSSFrameConstructor.cpp
layout/mathml/Makefile.in
layout/mathml/nsMathMLParts.h
layout/mathml/nsMathMLmoverFrame.cpp
layout/mathml/nsMathMLmoverFrame.h
layout/mathml/nsMathMLmunderFrame.cpp
layout/mathml/nsMathMLmunderFrame.h
layout/mathml/nsMathMLmunderoverFrame.cpp
--- a/layout/base/nsCSSFrameConstructor.cpp
+++ b/layout/base/nsCSSFrameConstructor.cpp
@@ -4641,18 +4641,18 @@ nsCSSFrameConstructor::FindMathMLData(El
     SIMPLE_MATHML_CREATE(mn_, NS_NewMathMLTokenFrame),
     SIMPLE_MATHML_CREATE(ms_, NS_NewMathMLTokenFrame),
     SIMPLE_MATHML_CREATE(mtext_, NS_NewMathMLTokenFrame),
     SIMPLE_MATHML_CREATE(mo_, NS_NewMathMLmoFrame),
     SIMPLE_MATHML_CREATE(mfrac_, NS_NewMathMLmfracFrame),
     SIMPLE_MATHML_CREATE(msup_, NS_NewMathMLmsupFrame),
     SIMPLE_MATHML_CREATE(msub_, NS_NewMathMLmsubFrame),
     SIMPLE_MATHML_CREATE(msubsup_, NS_NewMathMLmsubsupFrame),
-    SIMPLE_MATHML_CREATE(munder_, NS_NewMathMLmunderFrame),
-    SIMPLE_MATHML_CREATE(mover_, NS_NewMathMLmoverFrame),
+    SIMPLE_MATHML_CREATE(munder_, NS_NewMathMLmunderoverFrame),
+    SIMPLE_MATHML_CREATE(mover_, NS_NewMathMLmunderoverFrame),
     SIMPLE_MATHML_CREATE(munderover_, NS_NewMathMLmunderoverFrame),
     SIMPLE_MATHML_CREATE(mphantom_, NS_NewMathMLmphantomFrame),
     SIMPLE_MATHML_CREATE(mpadded_, NS_NewMathMLmpaddedFrame),
     SIMPLE_MATHML_CREATE(mspace_, NS_NewMathMLmspaceFrame),
     SIMPLE_MATHML_CREATE(none, NS_NewMathMLmspaceFrame),
     SIMPLE_MATHML_CREATE(mprescripts_, NS_NewMathMLmspaceFrame),
     SIMPLE_MATHML_CREATE(mfenced_, NS_NewMathMLmfencedFrame),
     SIMPLE_MATHML_CREATE(mmultiscripts_, NS_NewMathMLmmultiscriptsFrame),
--- a/layout/mathml/Makefile.in
+++ b/layout/mathml/Makefile.in
@@ -71,18 +71,16 @@ CPPSRCS =         nsMathMLChar.cpp		    
                   nsMathMLmphantomFrame.cpp		\
                   nsMathMLmfencedFrame.cpp		\
                   nsMathMLmfracFrame.cpp		\
                   nsMathMLmsupFrame.cpp			\
                   nsMathMLmsubFrame.cpp			\
                   nsMathMLmsubsupFrame.cpp		\
                   nsMathMLmmultiscriptsFrame.cpp	\
                   nsMathMLmtableFrame.cpp		\
-                  nsMathMLmunderFrame.cpp		\
-                  nsMathMLmoverFrame.cpp		\
                   nsMathMLmunderoverFrame.cpp		\
                   nsMathMLmpaddedFrame.cpp		\
                   nsMathMLmspaceFrame.cpp		\
                   nsMathMLmstyleFrame.cpp		\
                   nsMathMLmsqrtFrame.cpp		\
                   nsMathMLmrootFrame.cpp		\
                   nsMathMLmactionFrame.cpp		\
                   nsMathMLmencloseFrame.cpp		\
--- a/layout/mathml/nsMathMLParts.h
+++ b/layout/mathml/nsMathMLParts.h
@@ -51,18 +51,16 @@ nsIFrame* NS_NewMathMLmphantomFrame(nsIP
 nsIFrame* NS_NewMathMLmpaddedFrame(nsIPresShell* aPresShell, nsStyleContext* aContext);
 nsIFrame* NS_NewMathMLmspaceFrame(nsIPresShell* aPresShell, nsStyleContext* aContext);
 nsIFrame* NS_NewMathMLmsFrame(nsIPresShell* aPresShell, nsStyleContext* aContext);
 nsIFrame* NS_NewMathMLmfencedFrame(nsIPresShell* aPresShell, nsStyleContext* aContext);
 nsIFrame* NS_NewMathMLmfracFrame(nsIPresShell* aPresShell, nsStyleContext* aContext);
 nsIFrame* NS_NewMathMLmsubFrame(nsIPresShell* aPresShell, nsStyleContext* aContext);
 nsIFrame* NS_NewMathMLmsupFrame(nsIPresShell* aPresShell, nsStyleContext* aContext);
 nsIFrame* NS_NewMathMLmsubsupFrame(nsIPresShell* aPresShell, nsStyleContext* aContext);
-nsIFrame* NS_NewMathMLmunderFrame(nsIPresShell* aPresShell, nsStyleContext* aContext);
-nsIFrame* NS_NewMathMLmoverFrame(nsIPresShell* aPresShell, nsStyleContext* aContext);
 nsIFrame* NS_NewMathMLmunderoverFrame(nsIPresShell* aPresShell, nsStyleContext* aContext);
 nsIFrame* NS_NewMathMLmmultiscriptsFrame(nsIPresShell* aPresShell, nsStyleContext* aContext);
 nsIFrame* NS_NewMathMLmstyleFrame(nsIPresShell* aPresShell, nsStyleContext* aContext);
 nsIFrame* NS_NewMathMLmtableOuterFrame(nsIPresShell* aPresShell, nsStyleContext* aContext);
 nsIFrame* NS_NewMathMLmtableFrame(nsIPresShell* aPresShell, nsStyleContext* aContext);
 nsIFrame* NS_NewMathMLmtrFrame(nsIPresShell* aPresShell, nsStyleContext* aContext);
 nsIFrame* NS_NewMathMLmtdFrame(nsIPresShell* aPresShell, nsStyleContext* aContext);
 nsIFrame* NS_NewMathMLmtdInnerFrame(nsIPresShell* aPresShell, nsStyleContext* aContext);
deleted file mode 100644
--- a/layout/mathml/nsMathMLmoverFrame.cpp
+++ /dev/null
@@ -1,409 +0,0 @@
-/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
-/* ***** BEGIN LICENSE BLOCK *****
- * Version: MPL 1.1/GPL 2.0/LGPL 2.1
- *
- * The contents of this file are subject to the Mozilla Public License Version
- * 1.1 (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.mozilla.org/MPL/
- *
- * Software distributed under the License is distributed on an "AS IS" basis,
- * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
- * for the specific language governing rights and limitations under the
- * License.
- *
- * The Original Code is Mozilla MathML Project.
- *
- * The Initial Developer of the Original Code is
- * The University Of Queensland.
- * Portions created by the Initial Developer are Copyright (C) 1999
- * the Initial Developer. All Rights Reserved.
- *
- * Contributor(s):
- *   Roger B. Sidje <rbs@maths.uq.edu.au>
- *   David J. Fiddes <D.J.Fiddes@hw.ac.uk>
- *   Shyjan Mahamud <mahamud@cs.cmu.edu>
- *   Pierre Phaneuf <pp@ludusdesign.com>
- *
- * Alternatively, the contents of this file may be used under the terms of
- * either of the GNU General Public License Version 2 or later (the "GPL"),
- * or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
- * in which case the provisions of the GPL or the LGPL are applicable instead
- * of those above. If you wish to allow use of your version of this file only
- * under the terms of either the GPL or the LGPL, and not to allow others to
- * use your version of this file under the terms of the MPL, indicate your
- * decision by deleting the provisions above and replace them with the notice
- * and other provisions required by the GPL or the LGPL. If you do not delete
- * the provisions above, a recipient may use your version of this file under
- * the terms of any one of the MPL, the GPL or the LGPL.
- *
- * ***** END LICENSE BLOCK ***** */
-
-
-#include "nsCOMPtr.h"
-#include "nsFrame.h"
-#include "nsPresContext.h"
-#include "nsStyleContext.h"
-#include "nsStyleConsts.h"
-#include "nsINameSpaceManager.h"
-#include "nsRenderingContext.h"
-
-#include "nsMathMLmoverFrame.h"
-#include "nsMathMLmsupFrame.h"
-
-//
-// <mover> -- attach an overscript to a base - implementation
-//
-
-nsIFrame*
-NS_NewMathMLmoverFrame(nsIPresShell* aPresShell, nsStyleContext* aContext)
-{
-  return new (aPresShell) nsMathMLmoverFrame(aContext);
-}
-
-NS_IMPL_FRAMEARENA_HELPERS(nsMathMLmoverFrame)
-
-nsMathMLmoverFrame::~nsMathMLmoverFrame()
-{
-}
-
-NS_IMETHODIMP
-nsMathMLmoverFrame::AttributeChanged(PRInt32         aNameSpaceID,
-                                     nsIAtom*        aAttribute,
-                                     PRInt32         aModType)
-{
-  if (nsGkAtoms::accent_ == aAttribute) {
-    // When we have automatic data to update within ourselves, we ask our
-    // parent to re-layout its children
-    return ReLayoutChildren(mParent);
-  }
-
-  return nsMathMLContainerFrame::
-         AttributeChanged(aNameSpaceID, aAttribute, aModType);
-}
-
-NS_IMETHODIMP
-nsMathMLmoverFrame::UpdatePresentationData(PRUint32        aFlagsValues,
-                                           PRUint32        aFlagsToUpdate)
-{
-  nsMathMLContainerFrame::UpdatePresentationData(aFlagsValues, aFlagsToUpdate);
-  // disable the stretch-all flag if we are going to act like a superscript
-  if ( NS_MATHML_EMBELLISH_IS_MOVABLELIMITS(mEmbellishData.flags) &&
-      !NS_MATHML_IS_DISPLAYSTYLE(mPresentationData.flags)) {
-    mPresentationData.flags &= ~NS_MATHML_STRETCH_ALL_CHILDREN_HORIZONTALLY;
-  }
-  else {
-    mPresentationData.flags |= NS_MATHML_STRETCH_ALL_CHILDREN_HORIZONTALLY;
-  }
-  return NS_OK;
-}
-
-NS_IMETHODIMP
-nsMathMLmoverFrame::UpdatePresentationDataFromChildAt(PRInt32         aFirstIndex,
-                                                      PRInt32         aLastIndex,
-                                                      PRUint32        aFlagsValues,
-                                                      PRUint32        aFlagsToUpdate)
-{
-  // mover is special... The REC says:
-  // Within overscript, <mover> always sets displaystyle to "false", 
-  // but increments scriptlevel by 1 only when accent is "false".
-  // This means that
-  // 1. don't allow displaystyle to change in the overscript
-  // 2. if the value of the accent is changed, we need to recompute the
-  //    scriptlevel of the overscript. The problem is that the accent
-  //    can change in the <mo> deep down the embellished hierarchy
-
-  // Do #1 here, never allow displaystyle to be changed in the overscript
-  PRInt32 index = 0;
-  nsIFrame* childFrame = mFrames.FirstChild();
-  while (childFrame) {
-    if ((index >= aFirstIndex) &&
-        ((aLastIndex <= 0) || ((aLastIndex > 0) && (index <= aLastIndex)))) {
-      if (index > 0) {
-        // disable the flag
-        aFlagsToUpdate &= ~NS_MATHML_DISPLAYSTYLE;
-        aFlagsValues &= ~NS_MATHML_DISPLAYSTYLE;
-      }
-      PropagatePresentationDataFor(childFrame, aFlagsValues, aFlagsToUpdate);
-    }
-    index++;
-    childFrame = childFrame->GetNextSibling();
-  }
-  return NS_OK;
-
-  // For #2, changing the accent attribute will trigger a re-build of
-  // all automatic data in the embellished hierarchy
-}
-
-NS_IMETHODIMP
-nsMathMLmoverFrame::InheritAutomaticData(nsIFrame* aParent)
-{
-  // let the base class get the default from our parent
-  nsMathMLContainerFrame::InheritAutomaticData(aParent);
-
-  mPresentationData.flags |= NS_MATHML_STRETCH_ALL_CHILDREN_HORIZONTALLY;
-
-  return NS_OK;
-}
-
-NS_IMETHODIMP
-nsMathMLmoverFrame::TransmitAutomaticData()
-{
-  // At this stage, all our children are in sync and we can fully
-  // resolve our own mEmbellishData struct
-  //---------------------------------------------------------------------
-
-  /* The REC says:
-  The default value of accent is false, unless overscript
-  is an <mo> element or an embellished operator. If overscript is
-  an <mo> element, the value of its accent attribute is used as
-  the default value of accent. If overscript is an embellished 
-  operator, the accent attribute of the <mo> element at its
-  core is used as the default value. As with all attributes, an
-  explicitly given value overrides the default.
-
-XXX The winner is the outermost in conflicting settings like these:
-<mover accent='true'>
-  <mi>...</mi>
-  <mo accent='false'> ... </mo>
-</mover>
-   */
-
-  nsIFrame* overscriptFrame = nsnull;
-  nsIFrame* baseFrame = mFrames.FirstChild();
-  if (baseFrame)
-    overscriptFrame = baseFrame->GetNextSibling();
-
-  // if our base is an embellished operator, let its state bubble to us (in particular,
-  // this is where we get the flag for NS_MATHML_EMBELLISH_MOVABLELIMITS). Our flags
-  // are reset to the default values of false if the base frame isn't embellished.
-  mPresentationData.baseFrame = baseFrame;
-  GetEmbellishDataFrom(baseFrame, mEmbellishData);
-
-  // The default value of accent is false, unless the overscript is embellished
-  // and its core <mo> is an accent
-  nsEmbellishData embellishData;
-  GetEmbellishDataFrom(overscriptFrame, embellishData);
-  if (NS_MATHML_EMBELLISH_IS_ACCENT(embellishData.flags))
-    mEmbellishData.flags |= NS_MATHML_EMBELLISH_ACCENTOVER;
-  else
-    mEmbellishData.flags &= ~NS_MATHML_EMBELLISH_ACCENTOVER;
-
-  // if we have an accent attribute, it overrides what the overscript said
-  nsAutoString value;
-  if (GetAttribute(mContent, mPresentationData.mstyle, nsGkAtoms::accent_,
-                   value)) {
-    if (value.EqualsLiteral("true")) {
-      mEmbellishData.flags |= NS_MATHML_EMBELLISH_ACCENTOVER;
-    } else if (value.EqualsLiteral("false")) {
-      mEmbellishData.flags &= ~NS_MATHML_EMBELLISH_ACCENTOVER;
-    }
-  }
-
-  // disable the stretch-all flag if we are going to act like a superscript
-  if ( NS_MATHML_EMBELLISH_IS_MOVABLELIMITS(mEmbellishData.flags) &&
-      !NS_MATHML_IS_DISPLAYSTYLE(mPresentationData.flags))
-    mPresentationData.flags &= ~NS_MATHML_STRETCH_ALL_CHILDREN_HORIZONTALLY;
-
-  // Now transmit any change that we want to our children so that they
-  // can update their mPresentationData structs
-  //---------------------------------------------------------------------
-
-  /* The REC says:
-     Within overscript, <mover> always sets displaystyle to "false", 
-     but increments scriptlevel by 1 only when accent is "false".
-
-     The TeXBook treats 'over' like a superscript, so p.141 or Rule 13a
-     say it shouldn't be compressed. However, The TeXBook says
-     that math accents and \overline change uncramped styles to their
-     cramped counterparts.
-  */
-  SetIncrementScriptLevel(1, !NS_MATHML_EMBELLISH_IS_ACCENTOVER(mEmbellishData.flags));
-  PRUint32 compress = NS_MATHML_EMBELLISH_IS_ACCENTOVER(mEmbellishData.flags)
-    ? NS_MATHML_COMPRESSED : 0;
-  PropagatePresentationDataFor(overscriptFrame,
-    ~NS_MATHML_DISPLAYSTYLE | compress,
-     NS_MATHML_DISPLAYSTYLE | compress);
-
-  return NS_OK;
-}
-
-/*
-The REC says:
-* If the base is an operator with movablelimits="true" (or an embellished
-  operator whose <mo> element core has movablelimits="true"), and
-  displaystyle="false", then overscript is drawn in a superscript
-  position. In this case, the accent attribute is ignored. This is
-  often used for limits on symbols such as &sum;. 
-
-i.e.:
- if ( NS_MATHML_EMBELLISH_IS_MOVABLELIMITS(mEmbellishData.flags) &&
-     !NS_MATHML_IS_DISPLAYSTYLE(mPresentationData.flags)) {
-  // place like superscript
- }
- else {
-  // place like overscript 
- }
-*/
-
-/* virtual */ nsresult
-nsMathMLmoverFrame::Place(nsRenderingContext& aRenderingContext,
-                          PRBool               aPlaceOrigin,
-                          nsHTMLReflowMetrics& aDesiredSize)
-{ 
-  if ( NS_MATHML_EMBELLISH_IS_MOVABLELIMITS(mEmbellishData.flags) &&
-      !NS_MATHML_IS_DISPLAYSTYLE(mPresentationData.flags)) {
-    // place like superscript
-    return nsMathMLmsupFrame::PlaceSuperScript(PresContext(),
-                                               aRenderingContext,
-                                               aPlaceOrigin,
-                                               aDesiredSize,
-                                               this, 0, nsPresContext::CSSPointsToAppUnits(0.5f));
-  }
-
-  ////////////////////////////////////
-  // Get the children's desired sizes
-
-  nsBoundingMetrics bmBase, bmOver;
-  nsHTMLReflowMetrics baseSize;
-  nsHTMLReflowMetrics overSize;
-  nsIFrame* overFrame = nsnull;
-  nsIFrame* baseFrame = mFrames.FirstChild();
-  if (baseFrame)
-    overFrame = baseFrame->GetNextSibling();
-  if (!baseFrame || !overFrame || overFrame->GetNextSibling()) {
-    // report an error, encourage people to get their markups in order
-    return ReflowError(aRenderingContext, aDesiredSize);
-  }
-  GetReflowAndBoundingMetricsFor(baseFrame, baseSize, bmBase);
-  GetReflowAndBoundingMetricsFor(overFrame, overSize, bmOver);
-
-  nscoord onePixel = nsPresContext::CSSPixelsToAppUnits(1);
-
-  ////////////////////
-  // Place Children
-
-  aRenderingContext.SetFont(GetStyleFont()->mFont,
-                            PresContext()->GetUserFontSet());
-  nsFontMetrics* fm = aRenderingContext.FontMetrics();
-
-  nscoord xHeight = fm->XHeight();
-
-  nscoord ruleThickness;
-  GetRuleThickness (aRenderingContext, fm, ruleThickness);
-
-  // there are 2 different types of placement depending on 
-  // whether we want an accented overscript or not
-
-  nscoord correction = 0;
-  GetItalicCorrection (bmBase, correction);
-
-  nscoord delta1 = 0; // gap between base and overscript
-  nscoord delta2 = 0; // extra space above overscript
-  if (!NS_MATHML_EMBELLISH_IS_ACCENTOVER(mEmbellishData.flags)) {    
-    // Rule 13a, App. G, TeXbook
-    nscoord bigOpSpacing1, bigOpSpacing3, bigOpSpacing5, dummy; 
-    GetBigOpSpacings (fm, 
-                      bigOpSpacing1, dummy, 
-                      bigOpSpacing3, dummy, 
-                      bigOpSpacing5);
-    delta1 = NS_MAX(bigOpSpacing1, (bigOpSpacing3 - bmOver.descent));
-    delta2 = bigOpSpacing5;
-
-    // XXX This is not a TeX rule... 
-    // delta1 (as computed above) can become really big when bmOver.descent is
-    // negative,  e.g., if the content is &OverBar. In such case, we use the height
-    if (bmOver.descent < 0)    
-      delta1 = NS_MAX(bigOpSpacing1, (bigOpSpacing3 - (bmOver.ascent + bmOver.descent)));
-  }
-  else {
-    // Rule 12, App. G, TeXbook
-    // We are going to modify this rule to make it more general.
-    // The idea behind Rule 12 in the TeXBook is to keep the accent
-    // as close to the base as possible, while ensuring that the
-    // distance between the *baseline* of the accent char and 
-    // the *baseline* of the base is atleast x-height. 
-    // The idea is that for normal use, we would like all the accents
-    // on a line to line up atleast x-height above the baseline 
-    // if possible. 
-    // When the ascent of the base is >= x-height, 
-    // the baseline of the accent char is placed just above the base
-    // (specifically, the baseline of the accent char is placed 
-    // above the baseline of the base by the ascent of the base).
-    // For ease of implementation, 
-    // this assumes that the font-designer designs accents 
-    // in such a way that the bottom of the accent is atleast x-height
-    // above its baseline, otherwise there will be collisions
-    // with the base. Also there should be proper padding between
-    // the bottom of the accent char and its baseline.
-    // The above rule may not be obvious from a first
-    // reading of rule 12 in the TeXBook !!!
-    // The mathml <mover> tag can use accent chars that
-    // do not follow this convention. So we modify TeX's rule 
-    // so that TeX's rule gets subsumed for accents that follow 
-    // TeX's convention,
-    // while also allowing accents that do not follow the convention :
-    // we try to keep the *bottom* of the accent char atleast x-height 
-    // from the baseline of the base char. we also slap on an extra
-    // padding between the accent and base chars.
-    delta1 = ruleThickness + onePixel/2; // we have at least the padding
-    if (bmBase.ascent < xHeight) { 
-      // also ensure at least x-height above the baseline of the base
-      delta1 += xHeight - bmBase.ascent;
-    }
-    delta2 = ruleThickness;
-  }
-  // empty over?
-  if (!(bmOver.ascent + bmOver.descent)) delta1 = 0;
-
-  nscoord dxBase, dxOver = 0;
-
-  // Ad-hoc - This is to override fonts which have ready-made _accent_
-  // glyphs with negative lbearing and rbearing. We want to position
-  // the overscript ourselves
-  nscoord overWidth = bmOver.width;
-  if (!overWidth && (bmOver.rightBearing - bmOver.leftBearing > 0)) {
-    overWidth = bmOver.rightBearing - bmOver.leftBearing;
-    dxOver = -bmOver.leftBearing;
-  }
-
-  if (NS_MATHML_EMBELLISH_IS_ACCENTOVER(mEmbellishData.flags)) {
-    mBoundingMetrics.width = bmBase.width; 
-    dxOver += correction + (mBoundingMetrics.width - overWidth)/2;
-  }
-  else {
-    mBoundingMetrics.width = NS_MAX(bmBase.width, overWidth);
-    dxOver += correction/2 + (mBoundingMetrics.width - overWidth)/2;
-  }
-  dxBase = (mBoundingMetrics.width - bmBase.width) / 2;
-
-  mBoundingMetrics.ascent = 
-    bmOver.ascent + bmOver.descent + delta1 + bmBase.ascent;
-  mBoundingMetrics.descent = bmBase.descent;
-  mBoundingMetrics.leftBearing = 
-    NS_MIN(dxBase + bmBase.leftBearing, dxOver + bmOver.leftBearing);
-  mBoundingMetrics.rightBearing = 
-    NS_MAX(dxBase + bmBase.rightBearing, dxOver + bmOver.rightBearing);
-
-  aDesiredSize.ascent = 
-    NS_MAX(mBoundingMetrics.ascent + delta2,
-           overSize.ascent + bmOver.descent + delta1 + bmBase.ascent);
-  aDesiredSize.height = aDesiredSize.ascent +
-    baseSize.height - baseSize.ascent;
-  aDesiredSize.width = mBoundingMetrics.width;
-  aDesiredSize.mBoundingMetrics = mBoundingMetrics;
-
-  mReference.x = 0;
-  mReference.y = aDesiredSize.ascent;
-
-  if (aPlaceOrigin) {
-    // place base
-    nscoord dy = aDesiredSize.ascent - baseSize.ascent;
-    FinishReflowChild (baseFrame, PresContext(), nsnull, baseSize, dxBase, dy, 0);
-    // place overscript
-    dy = aDesiredSize.ascent - 
-      mBoundingMetrics.ascent + bmOver.ascent - overSize.ascent;
-    FinishReflowChild (overFrame, PresContext(), nsnull, overSize, dxOver, dy, 0);
-  }
-  return NS_OK;
-}
deleted file mode 100644
--- a/layout/mathml/nsMathMLmoverFrame.h
+++ /dev/null
@@ -1,91 +0,0 @@
-/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
-/* ***** BEGIN LICENSE BLOCK *****
- * Version: MPL 1.1/GPL 2.0/LGPL 2.1
- *
- * The contents of this file are subject to the Mozilla Public License Version
- * 1.1 (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.mozilla.org/MPL/
- *
- * Software distributed under the License is distributed on an "AS IS" basis,
- * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
- * for the specific language governing rights and limitations under the
- * License.
- *
- * The Original Code is Mozilla MathML Project.
- *
- * The Initial Developer of the Original Code is
- * The University Of Queensland.
- * Portions created by the Initial Developer are Copyright (C) 1999
- * the Initial Developer. All Rights Reserved.
- *
- * Contributor(s):
- *   Roger B. Sidje <rbs@maths.uq.edu.au>
- *   David J. Fiddes <D.J.Fiddes@hw.ac.uk>
- *   Shyjan Mahamud <mahamud@cs.cmu.edu>
- *
- * Alternatively, the contents of this file may be used under the terms of
- * either of the GNU General Public License Version 2 or later (the "GPL"),
- * or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
- * in which case the provisions of the GPL or the LGPL are applicable instead
- * of those above. If you wish to allow use of your version of this file only
- * under the terms of either the GPL or the LGPL, and not to allow others to
- * use your version of this file under the terms of the MPL, indicate your
- * decision by deleting the provisions above and replace them with the notice
- * and other provisions required by the GPL or the LGPL. If you do not delete
- * the provisions above, a recipient may use your version of this file under
- * the terms of any one of the MPL, the GPL or the LGPL.
- *
- * ***** END LICENSE BLOCK ***** */
-
-#ifndef nsMathMLmoverFrame_h___
-#define nsMathMLmoverFrame_h___
-
-#include "nsCOMPtr.h"
-#include "nsMathMLContainerFrame.h"
-
-//
-// <mover> -- attach an overscript to a base
-//
-
-class nsMathMLmoverFrame : public nsMathMLContainerFrame {
-public:
-  NS_DECL_FRAMEARENA_HELPERS
-
-  friend nsIFrame* NS_NewMathMLmoverFrame(nsIPresShell* aPresShell, nsStyleContext* aContext);
-
-  virtual nsresult
-  Place(nsRenderingContext& aRenderingContext,
-        PRBool               aPlaceOrigin,
-        nsHTMLReflowMetrics& aDesiredSize);
-
-  NS_IMETHOD
-  InheritAutomaticData(nsIFrame* aParent);
-
-  NS_IMETHOD
-  TransmitAutomaticData();
-
-  NS_IMETHOD
-  UpdatePresentationData(PRUint32        aFlagsValues,
-                         PRUint32        aFlagsToUpdate);
-
-  NS_IMETHOD
-  UpdatePresentationDataFromChildAt(PRInt32         aFirstIndex,
-                                    PRInt32         aLastIndex,
-                                    PRUint32        aFlagsValues,
-                                    PRUint32        aFlagsToUpdate);
-
-  NS_IMETHOD
-  AttributeChanged(PRInt32         aNameSpaceID,
-                   nsIAtom*        aAttribute,
-                   PRInt32         aModType);
-
-protected:
-  nsMathMLmoverFrame(nsStyleContext* aContext) : nsMathMLContainerFrame(aContext) {}
-  virtual ~nsMathMLmoverFrame();
-  
-  virtual PRIntn GetSkipSides() const { return 0; }
-};
-
-
-#endif /* nsMathMLmoverFrame_h___ */
deleted file mode 100644
--- a/layout/mathml/nsMathMLmunderFrame.cpp
+++ /dev/null
@@ -1,369 +0,0 @@
-/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
-/* ***** BEGIN LICENSE BLOCK *****
- * Version: MPL 1.1/GPL 2.0/LGPL 2.1
- *
- * The contents of this file are subject to the Mozilla Public License Version
- * 1.1 (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.mozilla.org/MPL/
- *
- * Software distributed under the License is distributed on an "AS IS" basis,
- * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
- * for the specific language governing rights and limitations under the
- * License.
- *
- * The Original Code is Mozilla MathML Project.
- *
- * The Initial Developer of the Original Code is
- * The University Of Queensland.
- * Portions created by the Initial Developer are Copyright (C) 1999
- * the Initial Developer. All Rights Reserved.
- *
- * Contributor(s):
- *   Roger B. Sidje <rbs@maths.uq.edu.au>
- *   David J. Fiddes <D.J.Fiddes@hw.ac.uk>
- *   Shyjan Mahamud <mahamud@cs.cmu.edu>
- *   Pierre Phaneuf <pp@ludusdesign.com>
- *
- * Alternatively, the contents of this file may be used under the terms of
- * either of the GNU General Public License Version 2 or later (the "GPL"),
- * or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
- * in which case the provisions of the GPL or the LGPL are applicable instead
- * of those above. If you wish to allow use of your version of this file only
- * under the terms of either the GPL or the LGPL, and not to allow others to
- * use your version of this file under the terms of the MPL, indicate your
- * decision by deleting the provisions above and replace them with the notice
- * and other provisions required by the GPL or the LGPL. If you do not delete
- * the provisions above, a recipient may use your version of this file under
- * the terms of any one of the MPL, the GPL or the LGPL.
- *
- * ***** END LICENSE BLOCK ***** */
-
-
-#include "nsCOMPtr.h"
-#include "nsFrame.h"
-#include "nsPresContext.h"
-#include "nsStyleContext.h"
-#include "nsStyleConsts.h"
-#include "nsINameSpaceManager.h"
-#include "nsRenderingContext.h"
-
-#include "nsMathMLmunderFrame.h"
-#include "nsMathMLmsubFrame.h"
-
-//
-// <munder> -- attach an underscript to a base - implementation
-//
-
-nsIFrame*
-NS_NewMathMLmunderFrame(nsIPresShell* aPresShell, nsStyleContext* aContext)
-{
-  return new (aPresShell) nsMathMLmunderFrame(aContext);
-}
-
-NS_IMPL_FRAMEARENA_HELPERS(nsMathMLmunderFrame)
-
-nsMathMLmunderFrame::~nsMathMLmunderFrame()
-{
-}
-
-NS_IMETHODIMP
-nsMathMLmunderFrame::AttributeChanged(PRInt32         aNameSpaceID,
-                                      nsIAtom*        aAttribute,
-                                      PRInt32         aModType)
-{
-  if (nsGkAtoms::accentunder_ == aAttribute) {
-    // When we have automatic data to update within ourselves, we ask our
-    // parent to re-layout its children
-    return ReLayoutChildren(mParent);
-  }
-
-  return nsMathMLContainerFrame::
-         AttributeChanged(aNameSpaceID, aAttribute, aModType);
-}
-
-NS_IMETHODIMP
-nsMathMLmunderFrame::UpdatePresentationData(PRUint32        aFlagsValues,
-                                            PRUint32        aFlagsToUpdate)
-{
-  nsMathMLContainerFrame::UpdatePresentationData(aFlagsValues, aFlagsToUpdate);
-  // disable the stretch-all flag if we are going to act like a subscript
-  if ( NS_MATHML_EMBELLISH_IS_MOVABLELIMITS(mEmbellishData.flags) &&
-      !NS_MATHML_IS_DISPLAYSTYLE(mPresentationData.flags)) {
-    mPresentationData.flags &= ~NS_MATHML_STRETCH_ALL_CHILDREN_HORIZONTALLY;
-  }
-  else {
-    mPresentationData.flags |= NS_MATHML_STRETCH_ALL_CHILDREN_HORIZONTALLY;
-  }
-  return NS_OK;
-}
-
-NS_IMETHODIMP
-nsMathMLmunderFrame::UpdatePresentationDataFromChildAt(PRInt32         aFirstIndex,
-                                                       PRInt32         aLastIndex,
-                                                       PRUint32        aFlagsValues,
-                                                       PRUint32        aFlagsToUpdate)
-{
-  // munder is special... The REC says:
-  // Within underscript, <munder> always sets displaystyle to "false", 
-  // but increments scriptlevel by 1 only when accentunder is "false".
-  // This means that
-  // 1. don't allow displaystyle to change in the underscript
-  // 2. if the value of the accent is changed, we need to recompute the
-  //    scriptlevel of the underscript. The problem is that the accent
-  //    can change in the <mo> deep down the embellished hierarchy
-
-  // Do #1 here, never allow displaystyle to be changed in the underscript
-  PRInt32 index = 0;
-  nsIFrame* childFrame = mFrames.FirstChild();
-  while (childFrame) {
-    if ((index >= aFirstIndex) &&
-        ((aLastIndex <= 0) || ((aLastIndex > 0) && (index <= aLastIndex)))) {
-      if (index > 0) {
-        // disable the flag
-        aFlagsToUpdate &= ~NS_MATHML_DISPLAYSTYLE;
-        aFlagsValues &= ~NS_MATHML_DISPLAYSTYLE;
-      }
-      PropagatePresentationDataFor(childFrame, aFlagsValues, aFlagsToUpdate);
-    }
-    index++;
-    childFrame = childFrame->GetNextSibling();
-  }
-  return NS_OK;
-
-  // For #2, changing the accent attribute will trigger a re-build of
-  // all automatic data in the embellished hierarchy
-}
-
-NS_IMETHODIMP
-nsMathMLmunderFrame::InheritAutomaticData(nsIFrame* aParent)
-{
-  // let the base class get the default from our parent
-  nsMathMLContainerFrame::InheritAutomaticData(aParent);
-
-  mPresentationData.flags |= NS_MATHML_STRETCH_ALL_CHILDREN_HORIZONTALLY;
-
-  return NS_OK;
-}
-
-NS_IMETHODIMP
-nsMathMLmunderFrame::TransmitAutomaticData()
-{
-  // At this stage, all our children are in sync and we can fully
-  // resolve our own mEmbellishData struct
-  //---------------------------------------------------------------------
-
-  /* The REC says:
-  The default value of accentunder is false, unless underscript
-  is an <mo> element or an embellished operator.  If underscript is 
-  an <mo> element, the value of its accent attribute is used as the
-  default value of accentunder. If underscript is an embellished
-  operator, the accent attribute of the <mo> element at its
-  core is used as the default value. As with all attributes, an
-  explicitly given value overrides the default.
-
-XXX The winner is the outermost setting in conflicting settings like these:
-<munder accent='true'>
-  <mi>...</mi>
-  <mo accent='false'> ... </mo>
-</munder>
-   */
-
-  nsIFrame* underscriptFrame = nsnull;
-  nsIFrame* baseFrame = mFrames.FirstChild();
-  if (baseFrame)
-    underscriptFrame = baseFrame->GetNextSibling();
-
-  // if our base is an embellished operator, let its state bubble to us (in particular,
-  // this is where we get the flag for NS_MATHML_EMBELLISH_MOVABLELIMITS). Our flags
-  // are reset to the default values of false if the base frame isn't embellished.
-  mPresentationData.baseFrame = baseFrame;
-  GetEmbellishDataFrom(baseFrame, mEmbellishData);
-
-  // The default value of accentunder is false, unless the underscript is embellished
-  // and its core <mo> is an accent
-  nsEmbellishData embellishData;
-  GetEmbellishDataFrom(underscriptFrame, embellishData);
-  if (NS_MATHML_EMBELLISH_IS_ACCENT(embellishData.flags))
-    mEmbellishData.flags |= NS_MATHML_EMBELLISH_ACCENTUNDER;
-  else
-    mEmbellishData.flags &= ~NS_MATHML_EMBELLISH_ACCENTUNDER;
-
-  // if we have an accentunder attribute, it overrides what the underscript said
-  nsAutoString value;
-  if (GetAttribute(mContent, mPresentationData.mstyle, nsGkAtoms::accentunder_,
-                   value)) {
-    if (value.EqualsLiteral("true")) {
-      mEmbellishData.flags |= NS_MATHML_EMBELLISH_ACCENTUNDER;
-    } else if (value.EqualsLiteral("false")) {
-      mEmbellishData.flags &= ~NS_MATHML_EMBELLISH_ACCENTUNDER;
-    }
-  }
-
-  // disable the stretch-all flag if we are going to act like a superscript
-  if ( NS_MATHML_EMBELLISH_IS_MOVABLELIMITS(mEmbellishData.flags) &&
-      !NS_MATHML_IS_DISPLAYSTYLE(mPresentationData.flags))
-    mPresentationData.flags &= ~NS_MATHML_STRETCH_ALL_CHILDREN_HORIZONTALLY;
-
-  // Now transmit any change that we want to our children so that they
-  // can update their mPresentationData structs
-  //---------------------------------------------------------------------
-
-  /* The REC says:
-     Within underscript, <munder> always sets displaystyle to "false", 
-     but increments scriptlevel by 1 only when accentunder is "false".
-
-     The TeXBook treats 'under' like a subscript, so p.141 or Rule 13a 
-     say it should be compressed
-  */
-  SetIncrementScriptLevel(1, !NS_MATHML_EMBELLISH_IS_ACCENTUNDER(mEmbellishData.flags));
-  PropagatePresentationDataFor(underscriptFrame,
-    ~NS_MATHML_DISPLAYSTYLE | NS_MATHML_COMPRESSED,
-     NS_MATHML_DISPLAYSTYLE | NS_MATHML_COMPRESSED);
-
-  return NS_OK;
-}
-
-/*
-The REC says:
-* If the base is an operator with movablelimits="true" (or
-  an embellished operator whose <mo> element core has
-  movablelimits="true"), and displaystyle="false", then
-  underscript is drawn in a subscript position. In this case,
-  the accentunder attribute is ignored. This is often used
-  for limits on symbols such as &sum;. 
-
-i.e.,:
- if ( NS_MATHML_EMBELLISH_IS_MOVABLELIMITS(mEmbellishData.flags) &&
-     !NS_MATHML_IS_DISPLAYSTYLE(mPresentationData.flags)) {
-  // place like subscript
- }
- else {
-  // place like underscript 
- }
-*/
-
-/* virtual */ nsresult
-nsMathMLmunderFrame::Place(nsRenderingContext& aRenderingContext,
-                           PRBool               aPlaceOrigin,
-                           nsHTMLReflowMetrics& aDesiredSize)
-{
-  if ( NS_MATHML_EMBELLISH_IS_MOVABLELIMITS(mEmbellishData.flags) &&
-      !NS_MATHML_IS_DISPLAYSTYLE(mPresentationData.flags)) {
-    // place like subscript
-    return nsMathMLmsubFrame::PlaceSubScript(PresContext(),
-                                             aRenderingContext,
-                                             aPlaceOrigin,
-                                             aDesiredSize,
-                                             this, 0, nsPresContext::CSSPointsToAppUnits(0.5f));
-  }
-
-  ////////////////////////////////////
-  // Get the children's desired sizes
-
-  nsBoundingMetrics bmBase, bmUnder;
-  nsHTMLReflowMetrics baseSize;
-  nsHTMLReflowMetrics underSize;
-  nsIFrame* underFrame = nsnull;
-  nsIFrame* baseFrame = mFrames.FirstChild();
-  if (baseFrame)
-    underFrame = baseFrame->GetNextSibling();
-  if (!baseFrame || !underFrame || underFrame->GetNextSibling()) {
-    // report an error, encourage people to get their markups in order
-    return ReflowError(aRenderingContext, aDesiredSize);
-  }
-  GetReflowAndBoundingMetricsFor(baseFrame, baseSize, bmBase);
-  GetReflowAndBoundingMetricsFor(underFrame, underSize, bmUnder);
-
-  nscoord onePixel = nsPresContext::CSSPixelsToAppUnits(1);
-
-  ////////////////////
-  // Place Children
-
-  aRenderingContext.SetFont(GetStyleFont()->mFont,
-                            PresContext()->GetUserFontSet());
-  nsFontMetrics* fm = aRenderingContext.FontMetrics();
-
-  nscoord ruleThickness;
-  GetRuleThickness (aRenderingContext, fm, ruleThickness);
-
-  // there are 2 different types of placement depending on 
-  // whether we want an accented under or not
-
-  nscoord correction = 0;
-  GetItalicCorrection (bmBase, correction);
-
-  nscoord delta1 = 0; // gap between base and underscript
-  nscoord delta2 = 0; // extra space beneath underscript
-  if (!NS_MATHML_EMBELLISH_IS_ACCENTUNDER(mEmbellishData.flags)) {    
-    // Rule 13a, App. G, TeXbook
-    nscoord bigOpSpacing2, bigOpSpacing4, bigOpSpacing5, dummy; 
-    GetBigOpSpacings (fm, 
-                      dummy, bigOpSpacing2, 
-                      dummy, bigOpSpacing4, 
-                      bigOpSpacing5);
-    delta1 = NS_MAX(bigOpSpacing2, (bigOpSpacing4 - bmUnder.ascent));
-    delta2 = bigOpSpacing5;
-  }
-  else {
-    // No corresponding rule in TeXbook - we are on our own here
-    // XXX tune the gap delta between base and underscript 
-
-    // Should we use Rule 10 like \underline does?
-    delta1 = ruleThickness + onePixel/2;
-    delta2 = ruleThickness;
-  }
-  // empty under?
-  if (!(bmUnder.ascent + bmUnder.descent)) delta1 = 0;
-
-  nscoord dxBase, dxUnder = 0;
-
-  // Width of non-spacing marks is zero so use left and right bearing.
-  nscoord underWidth = bmUnder.width;
-  if (!underWidth) {
-    underWidth = bmUnder.rightBearing - bmUnder.leftBearing;
-    dxUnder = -bmUnder.leftBearing;
-  }
-
-  nscoord maxWidth = NS_MAX(bmBase.width, underWidth);
-  if (NS_MATHML_EMBELLISH_IS_ACCENTUNDER(mEmbellishData.flags)) {    
-    dxUnder += (maxWidth - underWidth)/2;
-  }
-  else {
-    dxUnder += -correction/2 + (maxWidth - underWidth)/2;
-  }
-  dxBase = (maxWidth - bmBase.width)/2;
-
-  mBoundingMetrics.width =
-    NS_MAX(dxBase + bmBase.width, dxUnder + bmUnder.width);
-  mBoundingMetrics.ascent = bmBase.ascent;
-  mBoundingMetrics.descent = 
-    bmBase.descent + delta1 + bmUnder.ascent + bmUnder.descent;
-  mBoundingMetrics.leftBearing = 
-    NS_MIN(dxBase + bmBase.leftBearing, dxUnder + bmUnder.leftBearing);
-  mBoundingMetrics.rightBearing = 
-    NS_MAX(dxBase + bmBase.rightBearing, dxUnder + bmUnder.rightBearing);
-
-  aDesiredSize.ascent = baseSize.ascent;
-  aDesiredSize.height = aDesiredSize.ascent +
-    NS_MAX(mBoundingMetrics.descent + delta2,
-           bmBase.descent + delta1 + bmUnder.ascent +
-             underSize.height - underSize.ascent);
-  aDesiredSize.width = mBoundingMetrics.width;
-  aDesiredSize.mBoundingMetrics = mBoundingMetrics;
-
-  mReference.x = 0;
-  mReference.y = aDesiredSize.ascent;
-
-  if (aPlaceOrigin) {
-    nscoord dy = 0;
-    // place base
-    FinishReflowChild(baseFrame, PresContext(), nsnull, baseSize, dxBase, dy, 0);
-    // place underscript
-    dy = aDesiredSize.ascent + mBoundingMetrics.descent - bmUnder.descent - underSize.ascent;
-    FinishReflowChild(underFrame, PresContext(), nsnull, underSize, dxUnder, dy, 0);
-  }
-
-  return NS_OK;
-}
-
deleted file mode 100644
--- a/layout/mathml/nsMathMLmunderFrame.h
+++ /dev/null
@@ -1,90 +0,0 @@
-/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
-/* ***** BEGIN LICENSE BLOCK *****
- * Version: MPL 1.1/GPL 2.0/LGPL 2.1
- *
- * The contents of this file are subject to the Mozilla Public License Version
- * 1.1 (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.mozilla.org/MPL/
- *
- * Software distributed under the License is distributed on an "AS IS" basis,
- * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
- * for the specific language governing rights and limitations under the
- * License.
- *
- * The Original Code is Mozilla MathML Project.
- *
- * The Initial Developer of the Original Code is
- * The University Of Queensland.
- * Portions created by the Initial Developer are Copyright (C) 1999
- * the Initial Developer. All Rights Reserved.
- *
- * Contributor(s):
- *   Roger B. Sidje <rbs@maths.uq.edu.au>
- *   David J. Fiddes <D.J.Fiddes@hw.ac.uk>
- *   Shyjan Mahamud <mahamud@cs.cmu.edu>
- *
- * Alternatively, the contents of this file may be used under the terms of
- * either of the GNU General Public License Version 2 or later (the "GPL"),
- * or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
- * in which case the provisions of the GPL or the LGPL are applicable instead
- * of those above. If you wish to allow use of your version of this file only
- * under the terms of either the GPL or the LGPL, and not to allow others to
- * use your version of this file under the terms of the MPL, indicate your
- * decision by deleting the provisions above and replace them with the notice
- * and other provisions required by the GPL or the LGPL. If you do not delete
- * the provisions above, a recipient may use your version of this file under
- * the terms of any one of the MPL, the GPL or the LGPL.
- *
- * ***** END LICENSE BLOCK ***** */
-
-#ifndef nsMathMLmunderFrame_h___
-#define nsMathMLmunderFrame_h___
-
-#include "nsCOMPtr.h"
-#include "nsMathMLContainerFrame.h"
-
-//
-// <munder> -- attach an underscript to a base 
-//
-
-class nsMathMLmunderFrame : public nsMathMLContainerFrame {
-public:
-  NS_DECL_FRAMEARENA_HELPERS
-
-  friend nsIFrame* NS_NewMathMLmunderFrame(nsIPresShell* aPresShell, nsStyleContext* aContext);
-
-  virtual nsresult
-  Place(nsRenderingContext& aRenderingContext,
-        PRBool               aPlaceOrigin,
-        nsHTMLReflowMetrics& aDesiredSize);
-
-  NS_IMETHOD
-  InheritAutomaticData(nsIFrame* aParent);
-
-  NS_IMETHOD
-  TransmitAutomaticData();
-
-  NS_IMETHOD
-  UpdatePresentationData(PRUint32        aFlagsValues,
-                         PRUint32        aFlagsToUpdate);
-
-  NS_IMETHOD
-  UpdatePresentationDataFromChildAt(PRInt32         aFirstIndex,
-                                    PRInt32         aLastIndex,
-                                    PRUint32        aFlagsValues,
-                                    PRUint32        aFlagsToUpdate);
-
-  NS_IMETHOD
-  AttributeChanged(PRInt32         aNameSpaceID,
-                   nsIAtom*        aAttribute,
-                   PRInt32         aModType);
-
-protected:
-  nsMathMLmunderFrame(nsStyleContext* aContext) : nsMathMLContainerFrame(aContext) {}
-  virtual ~nsMathMLmunderFrame();
-  
-  virtual PRIntn GetSkipSides() const { return 0; }
-};
-
-#endif /* nsMathMLmunderFrame_h___ */
--- a/layout/mathml/nsMathMLmunderoverFrame.cpp
+++ b/layout/mathml/nsMathMLmunderoverFrame.cpp
@@ -45,19 +45,23 @@
 #include "nsPresContext.h"
 #include "nsStyleContext.h"
 #include "nsStyleConsts.h"
 #include "nsINameSpaceManager.h"
 #include "nsRenderingContext.h"
 
 #include "nsMathMLmunderoverFrame.h"
 #include "nsMathMLmsubsupFrame.h"
+#include "nsMathMLmsupFrame.h"
+#include "nsMathMLmsubFrame.h"
 
 //
 // <munderover> -- attach an underscript-overscript pair to a base - implementation
+// <mover> -- attach an overscript to a base - implementation
+// <munder> -- attach an underscript to a base - implementation
 //
 
 nsIFrame*
 NS_NewMathMLmunderoverFrame(nsIPresShell* aPresShell, nsStyleContext* aContext)
 {
   return new (aPresShell) nsMathMLmunderoverFrame(aContext);
 }
 
@@ -157,73 +161,109 @@ nsMathMLmunderoverFrame::TransmitAutomat
 {
   // At this stage, all our children are in sync and we can fully
   // resolve our own mEmbellishData struct
   //---------------------------------------------------------------------
 
   /* 
   The REC says:
 
+  As regards munder (respectively mover) :
+  The default value of accentunder is false, unless underscript
+  is an <mo> element or an embellished operator.  If underscript is 
+  an <mo> element, the value of its accent attribute is used as the
+  default value of accentunder. If underscript is an embellished
+  operator, the accent attribute of the <mo> element at its
+  core is used as the default value. As with all attributes, an
+  explicitly given value overrides the default.
+
+XXX The winner is the outermost setting in conflicting settings like these:
+<munder accentunder='true'>
+  <mi>...</mi>
+  <mo accentunder='false'> ... </mo>
+</munder>
+
+  As regards munderover:
   The accent and accentunder attributes have the same effect as
   the attributes with the same names on <mover>  and <munder>, 
   respectively. Their default values are also computed in the 
   same manner as described for those elements, with the default
   value of accent depending on overscript and the default value
   of accentunder depending on underscript.
   */
 
   nsIFrame* overscriptFrame = nsnull;
   nsIFrame* underscriptFrame = nsnull;
   nsIFrame* baseFrame = mFrames.FirstChild();
-  if (baseFrame)
-    underscriptFrame = baseFrame->GetNextSibling();
-  if (underscriptFrame)
+  nsIAtom* tag = mContent->Tag();
+
+  if (baseFrame) {
+    if (tag == nsGkAtoms::munder_ ||
+        tag == nsGkAtoms::munderover_) {
+      underscriptFrame = baseFrame->GetNextSibling();
+    } else {
+      NS_ASSERTION(tag == nsGkAtoms::mover_, "mContent->Tag() not recognized");
+      overscriptFrame = baseFrame->GetNextSibling();
+    }
+  }
+  if (underscriptFrame &&
+      tag == nsGkAtoms::munderover_) {
     overscriptFrame = underscriptFrame->GetNextSibling();
 
+  }
+
   // if our base is an embellished operator, let its state bubble to us (in particular,
   // this is where we get the flag for NS_MATHML_EMBELLISH_MOVABLELIMITS). Our flags
   // are reset to the default values of false if the base frame isn't embellished.
   mPresentationData.baseFrame = baseFrame;
   GetEmbellishDataFrom(baseFrame, mEmbellishData);
 
   // The default value of accentunder is false, unless the underscript is embellished
   // and its core <mo> is an accent
   nsEmbellishData embellishData;
-  GetEmbellishDataFrom(underscriptFrame, embellishData);
-  if (NS_MATHML_EMBELLISH_IS_ACCENT(embellishData.flags))
-    mEmbellishData.flags |= NS_MATHML_EMBELLISH_ACCENTUNDER;
-  else
-    mEmbellishData.flags &= ~NS_MATHML_EMBELLISH_ACCENTUNDER;
+  nsAutoString value;
+  if (tag == nsGkAtoms::munder_ ||
+      tag == nsGkAtoms::munderover_) {
+    GetEmbellishDataFrom(underscriptFrame, embellishData);
+    if (NS_MATHML_EMBELLISH_IS_ACCENT(embellishData.flags)) {
+      mEmbellishData.flags |= NS_MATHML_EMBELLISH_ACCENTUNDER;
+    } else {
+      mEmbellishData.flags &= ~NS_MATHML_EMBELLISH_ACCENTUNDER;
+    }    
 
-  // if we have an accentunder attribute, it overrides what the underscript said
-  nsAutoString value;
-  if (GetAttribute(mContent, mPresentationData.mstyle, nsGkAtoms::accentunder_,
-                   value)) {
-    if (value.EqualsLiteral("true")) {
-      mEmbellishData.flags |= NS_MATHML_EMBELLISH_ACCENTUNDER;
-    } else if (value.EqualsLiteral("false")) {
-      mEmbellishData.flags &= ~NS_MATHML_EMBELLISH_ACCENTUNDER;
+    // if we have an accentunder attribute, it overrides what the underscript said
+    if (GetAttribute(mContent, mPresentationData.mstyle, nsGkAtoms::accentunder_,
+                     value)) {
+      if (value.EqualsLiteral("true")) {
+        mEmbellishData.flags |= NS_MATHML_EMBELLISH_ACCENTUNDER;
+      } else if (value.EqualsLiteral("false")) {
+        mEmbellishData.flags &= ~NS_MATHML_EMBELLISH_ACCENTUNDER;
+      }
     }
   }
 
   // The default value of accent is false, unless the overscript is embellished
   // and its core <mo> is an accent
-  GetEmbellishDataFrom(overscriptFrame, embellishData);
-  if (NS_MATHML_EMBELLISH_IS_ACCENT(embellishData.flags))
-    mEmbellishData.flags |= NS_MATHML_EMBELLISH_ACCENTOVER;
-  else
-    mEmbellishData.flags &= ~NS_MATHML_EMBELLISH_ACCENTOVER;
+  if (tag == nsGkAtoms::mover_ ||
+      tag == nsGkAtoms::munderover_) {
+    GetEmbellishDataFrom(overscriptFrame, embellishData);
+    if (NS_MATHML_EMBELLISH_IS_ACCENT(embellishData.flags)) {
+      mEmbellishData.flags |= NS_MATHML_EMBELLISH_ACCENTOVER;
+    } else {
+      mEmbellishData.flags &= ~NS_MATHML_EMBELLISH_ACCENTOVER;
+    }
 
-  // if we have an accent attribute, it overrides what the overscript said
-  if (GetAttribute(mContent, mPresentationData.mstyle, nsGkAtoms::accent_,
-                   value)) {
-    if (value.EqualsLiteral("true")) {
-      mEmbellishData.flags |= NS_MATHML_EMBELLISH_ACCENTOVER;
-    } else if (value.EqualsLiteral("false")) {
-      mEmbellishData.flags &= ~NS_MATHML_EMBELLISH_ACCENTOVER;
+    // if we have an accent attribute, it overrides what the overscript said
+    if (GetAttribute(mContent, mPresentationData.mstyle, nsGkAtoms::accent_,
+                     value)) {
+      if (value.EqualsLiteral("true")) {
+        mEmbellishData.flags |= NS_MATHML_EMBELLISH_ACCENTOVER;
+      } else if (value.EqualsLiteral("false")) {
+        mEmbellishData.flags &= ~NS_MATHML_EMBELLISH_ACCENTOVER;
+      }
     }
   }
 
   // disable the stretch-all flag if we are going to act like a superscript
   if ( NS_MATHML_EMBELLISH_IS_MOVABLELIMITS(mEmbellishData.flags) &&
       !NS_MATHML_IS_DISPLAYSTYLE(mPresentationData.flags))
     mPresentationData.flags &= ~NS_MATHML_STRETCH_ALL_CHILDREN_HORIZONTALLY;
 
@@ -238,32 +278,37 @@ nsMathMLmunderoverFrame::TransmitAutomat
      Within overscript, <munderover> always sets displaystyle to "false", 
      but increments scriptlevel by 1 only when accent is "false".
  
      The TeXBook treats 'over' like a superscript, so p.141 or Rule 13a
      say it shouldn't be compressed. However, The TeXBook says
      that math accents and \overline change uncramped styles to their
      cramped counterparts.
   */
-  PRUint32 compress = NS_MATHML_EMBELLISH_IS_ACCENTOVER(mEmbellishData.flags)
-    ? NS_MATHML_COMPRESSED : 0;
-  SetIncrementScriptLevel(2, !NS_MATHML_EMBELLISH_IS_ACCENTOVER(mEmbellishData.flags));
-  PropagatePresentationDataFor(overscriptFrame,
-    ~NS_MATHML_DISPLAYSTYLE | compress,
-     NS_MATHML_DISPLAYSTYLE | compress);
-
+  if (tag == nsGkAtoms::mover_ ||
+      tag == nsGkAtoms::munderover_) {
+    PRUint32 compress = NS_MATHML_EMBELLISH_IS_ACCENTOVER(mEmbellishData.flags)
+      ? NS_MATHML_COMPRESSED : 0;
+    SetIncrementScriptLevel(tag == nsGkAtoms::mover_ ? 1 : 2,
+                            !NS_MATHML_EMBELLISH_IS_ACCENTOVER(mEmbellishData.flags));
+    PropagatePresentationDataFor(overscriptFrame,
+                                 ~NS_MATHML_DISPLAYSTYLE | compress,
+                                 NS_MATHML_DISPLAYSTYLE | compress);
+  }
   /*
      The TeXBook treats 'under' like a subscript, so p.141 or Rule 13a 
      say it should be compressed
   */
-  SetIncrementScriptLevel(1, !NS_MATHML_EMBELLISH_IS_ACCENTUNDER(mEmbellishData.flags));
-  PropagatePresentationDataFor(underscriptFrame,
-    ~NS_MATHML_DISPLAYSTYLE | NS_MATHML_COMPRESSED,
-     NS_MATHML_DISPLAYSTYLE | NS_MATHML_COMPRESSED);
-
+  if (tag == nsGkAtoms::munder_ ||
+      tag == nsGkAtoms::munderover_) {
+    SetIncrementScriptLevel(1, !NS_MATHML_EMBELLISH_IS_ACCENTUNDER(mEmbellishData.flags));
+    PropagatePresentationDataFor(underscriptFrame,
+                                 ~NS_MATHML_DISPLAYSTYLE | NS_MATHML_COMPRESSED,
+                                 NS_MATHML_DISPLAYSTYLE | NS_MATHML_COMPRESSED);
+  }
   return NS_OK;
 }
 
 /*
 The REC says:
 *  If the base is an operator with movablelimits="true" (or an embellished
    operator whose <mo> element core has movablelimits="true"), and
    displaystyle="false", then underscript and overscript are drawn in
@@ -281,48 +326,96 @@ i.e.,:
  }
 */
 
 /* virtual */ nsresult
 nsMathMLmunderoverFrame::Place(nsRenderingContext& aRenderingContext,
                                PRBool               aPlaceOrigin,
                                nsHTMLReflowMetrics& aDesiredSize)
 {
+  nsIAtom* tag = mContent->Tag();
   if ( NS_MATHML_EMBELLISH_IS_MOVABLELIMITS(mEmbellishData.flags) &&
-      !NS_MATHML_IS_DISPLAYSTYLE(mPresentationData.flags)) {
-    // place like sub-superscript pair
-    return nsMathMLmsubsupFrame::PlaceSubSupScript(PresContext(),
-                                                   aRenderingContext,
-                                                   aPlaceOrigin,
-                                                   aDesiredSize,
-                                                   this, 0, 0,
-                                                   nsPresContext::CSSPointsToAppUnits(0.5f));
+       !NS_MATHML_IS_DISPLAYSTYLE(mPresentationData.flags)) {
+    //place like sub sup or subsup
+    nscoord scriptSpace = nsPresContext::CSSPointsToAppUnits(0.5f);
+    if (tag == nsGkAtoms::munderover_) {
+      return nsMathMLmsubsupFrame::PlaceSubSupScript(PresContext(),
+                                                     aRenderingContext,
+                                                     aPlaceOrigin,
+                                                     aDesiredSize,
+                                                     this, 0, 0,
+                                                     scriptSpace);
+    } else if (tag == nsGkAtoms::munder_) {
+      return nsMathMLmsubFrame::PlaceSubScript(PresContext(),
+                                               aRenderingContext,
+                                               aPlaceOrigin,
+                                               aDesiredSize,
+                                               this, 0,
+                                               scriptSpace);
+    } else {
+      NS_ASSERTION(tag == nsGkAtoms::mover_, "mContent->Tag() not recognized");
+      return nsMathMLmsupFrame::PlaceSuperScript(PresContext(),
+                                                 aRenderingContext,
+                                                 aPlaceOrigin,
+                                                 aDesiredSize,
+                                                 this, 0,
+                                                 scriptSpace);
+    }
+    
   }
 
   ////////////////////////////////////
   // Get the children's desired sizes
 
   nsBoundingMetrics bmBase, bmUnder, bmOver;
   nsHTMLReflowMetrics baseSize;
   nsHTMLReflowMetrics underSize;
   nsHTMLReflowMetrics overSize;
   nsIFrame* overFrame = nsnull;
   nsIFrame* underFrame = nsnull;
   nsIFrame* baseFrame = mFrames.FirstChild();
-  if (baseFrame)
-    underFrame = baseFrame->GetNextSibling();
-  if (underFrame)
+  underSize.ascent = 0; 
+  overSize.ascent = 0;
+  if (baseFrame) {
+    if (tag == nsGkAtoms::munder_ ||
+        tag == nsGkAtoms::munderover_) {
+      underFrame = baseFrame->GetNextSibling();
+    } else if (tag == nsGkAtoms::mover_) {
+      overFrame = baseFrame->GetNextSibling();
+    }
+  }
+  if (underFrame && tag == nsGkAtoms::munderover_) {
     overFrame = underFrame->GetNextSibling();
-  if (!baseFrame || !underFrame || !overFrame || overFrame->GetNextSibling()) {
-    // report an error, encourage people to get their markups in order
-    return ReflowError(aRenderingContext, aDesiredSize);
+  }
+  
+  if (tag == nsGkAtoms::munder_) {
+    if (!baseFrame || !underFrame || underFrame->GetNextSibling()) {
+      // report an error, encourage people to get their markups in order
+      return ReflowError(aRenderingContext, aDesiredSize);
+    }
+  }
+  if (tag == nsGkAtoms::mover_) {
+    if (!baseFrame || !overFrame || overFrame->GetNextSibling()) {
+      // report an error, encourage people to get their markups in order
+      return ReflowError(aRenderingContext, aDesiredSize);
+    }
+  }
+  if (tag == nsGkAtoms::munderover_) {
+    if (!baseFrame || !underFrame || !overFrame || overFrame->GetNextSibling()) {
+      // report an error, encourage people to get their markups in order
+      return ReflowError(aRenderingContext, aDesiredSize);
+    }
   }
   GetReflowAndBoundingMetricsFor(baseFrame, baseSize, bmBase);
-  GetReflowAndBoundingMetricsFor(underFrame, underSize, bmUnder);
-  GetReflowAndBoundingMetricsFor(overFrame, overSize, bmOver);
+  if (underFrame) {
+    GetReflowAndBoundingMetricsFor(underFrame, underSize, bmUnder);
+  }
+  if (overFrame) {
+    GetReflowAndBoundingMetricsFor(overFrame, overSize, bmOver);
+  }
 
   nscoord onePixel = nsPresContext::CSSPixelsToAppUnits(1);
 
   ////////////////////
   // Place Children
 
   aRenderingContext.SetFont(GetStyleFont()->mFont,
                             PresContext()->GetUserFontSet());
@@ -382,18 +475,47 @@ nsMathMLmunderoverFrame::Place(nsRenderi
     // XXX This is not a TeX rule... 
     // delta1 (as computed abvove) can become really big when bmOver.descent is
     // negative,  e.g., if the content is &OverBar. In such case, we use the height
     if (bmOver.descent < 0)    
       overDelta1 = NS_MAX(bigOpSpacing1, (bigOpSpacing3 - (bmOver.ascent + bmOver.descent)));
   }
   else {
     // Rule 12, App. G, TeXbook
+    // We are going to modify this rule to make it more general.
+    // The idea behind Rule 12 in the TeXBook is to keep the accent
+    // as close to the base as possible, while ensuring that the
+    // distance between the *baseline* of the accent char and 
+    // the *baseline* of the base is atleast x-height. 
+    // The idea is that for normal use, we would like all the accents
+    // on a line to line up atleast x-height above the baseline 
+    // if possible. 
+    // When the ascent of the base is >= x-height, 
+    // the baseline of the accent char is placed just above the base
+    // (specifically, the baseline of the accent char is placed 
+    // above the baseline of the base by the ascent of the base).
+    // For ease of implementation, 
+    // this assumes that the font-designer designs accents 
+    // in such a way that the bottom of the accent is atleast x-height
+    // above its baseline, otherwise there will be collisions
+    // with the base. Also there should be proper padding between
+    // the bottom of the accent char and its baseline.
+    // The above rule may not be obvious from a first
+    // reading of rule 12 in the TeXBook !!!
+    // The mathml <mover> tag can use accent chars that
+    // do not follow this convention. So we modify TeX's rule 
+    // so that TeX's rule gets subsumed for accents that follow 
+    // TeX's convention,
+    // while also allowing accents that do not follow the convention :
+    // we try to keep the *bottom* of the accent char atleast x-height 
+    // from the baseline of the base char. we also slap on an extra
+    // padding between the accent and base chars.
     overDelta1 = ruleThickness + onePixel/2;
-    if (bmBase.ascent < xHeight) { 
+    if (bmBase.ascent < xHeight) {
+      // also ensure at least x-height above the baseline of the base
       overDelta1 += xHeight - bmBase.ascent;
     }
     overDelta2 = ruleThickness;
   }
   // empty over?
   if (!(bmOver.ascent + bmOver.descent)) {
     overDelta1 = 0;
     overDelta2 = 0;
@@ -489,19 +611,26 @@ nsMathMLmunderoverFrame::Place(nsRenderi
   aDesiredSize.mBoundingMetrics = mBoundingMetrics;
 
   mReference.x = 0;
   mReference.y = aDesiredSize.ascent;
 
   if (aPlaceOrigin) {
     nscoord dy;
     // place overscript
-    dy = aDesiredSize.ascent - mBoundingMetrics.ascent + bmOver.ascent - overSize.ascent;
-    FinishReflowChild (overFrame, PresContext(), nsnull, overSize, dxOver, dy, 0);
+    if (overFrame) {
+      dy = aDesiredSize.ascent - mBoundingMetrics.ascent + bmOver.ascent 
+        - overSize.ascent;
+      FinishReflowChild (overFrame, PresContext(), nsnull, overSize, dxOver, dy, 0);
+    }
     // place base
     dy = aDesiredSize.ascent - baseSize.ascent;
     FinishReflowChild (baseFrame, PresContext(), nsnull, baseSize, dxBase, dy, 0);
     // place underscript
-    dy = aDesiredSize.ascent + mBoundingMetrics.descent - bmUnder.descent - underSize.ascent;
-    FinishReflowChild (underFrame, PresContext(), nsnull, underSize, dxUnder, dy, 0);
+    if (underFrame) {
+      dy = aDesiredSize.ascent + mBoundingMetrics.descent - bmUnder.descent 
+        - underSize.ascent;
+      FinishReflowChild (underFrame, PresContext(), nsnull, underSize,
+                         dxUnder, dy, 0);
+    }
   }
   return NS_OK;
 }