The Tor Browser: layout/mathml/nsMathMLmoFrame.cpp@b8a032363ba2 (annotated)

layout/mathml/nsMathMLmoFrame.cpp@b8a032363ba2 (annotated)

layout/mathml/nsMathMLmoFrame.cpp

Thu, 22 Jan 2015 13:21:57 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Thu, 22 Jan 2015 13:21:57 +0100
branch: TOR_BUG_9701
changeset 15: b8a032363ba2
permissions: -rw-r--r--

Incorporate requested changes from Mozilla in review:
https://bugzilla.mozilla.org/show_bug.cgi?id=1123480#c6

 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
 /* This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 #include "nsMathMLmoFrame.h"
 #include "nsPresContext.h"
 #include "nsRenderingContext.h"
 #include "nsContentUtils.h"
 #include "nsFrameSelection.h"
 #include "nsMathMLElement.h"
 #include <algorithm>
 //
 // <mo> -- operator, fence, or separator - implementation
 //
 // additional style context to be used by our MathMLChar.
 #define NS_MATHML_CHAR_STYLE_CONTEXT_INDEX   0
 nsIFrame*
 NS_NewMathMLmoFrame(nsIPresShell* aPresShell, nsStyleContext *aContext)
 {
   return new (aPresShell) nsMathMLmoFrame(aContext);
 }
 NS_IMPL_FRAMEARENA_HELPERS(nsMathMLmoFrame)
 nsMathMLmoFrame::~nsMathMLmoFrame()
 {
 }
 static const char16_t kApplyFunction  = char16_t(0x2061);
 static const char16_t kInvisibleTimes = char16_t(0x2062);
 static const char16_t kInvisibleSeparator = char16_t(0x2063);
 static const char16_t kInvisiblePlus = char16_t(0x2064);
 eMathMLFrameType
 nsMathMLmoFrame::GetMathMLFrameType()
 {
   return NS_MATHML_OPERATOR_IS_INVISIBLE(mFlags)
     ? eMathMLFrameType_OperatorInvisible
     : eMathMLFrameType_OperatorOrdinary;
 }
 // since a mouse click implies selection, we cannot just rely on the
 // frame's state bit in our child text frame. So we will first check
 // its selected state bit, and use this little helper to double check.
 bool
 nsMathMLmoFrame::IsFrameInSelection(nsIFrame* aFrame)
 {
   NS_ASSERTION(aFrame, "null arg");
   if (!aFrame || !aFrame->IsSelected())
     return false;
   const nsFrameSelection* frameSelection = aFrame->GetConstFrameSelection();
   SelectionDetails* details =
     frameSelection->LookUpSelection(aFrame->GetContent(), 0, 1, true);
   if (!details)
     return false;
   while (details) {
     SelectionDetails* next = details->mNext;
     delete details;
     details = next;
   }
   return true;
 }
 bool
 nsMathMLmoFrame::UseMathMLChar()
 {
   return (NS_MATHML_OPERATOR_GET_FORM(mFlags) &&
           NS_MATHML_OPERATOR_IS_MUTABLE(mFlags)) ||
     NS_MATHML_OPERATOR_IS_CENTERED(mFlags);
 }
 void
 nsMathMLmoFrame::BuildDisplayList(nsDisplayListBuilder*   aBuilder,
                                   const nsRect&           aDirtyRect,
                                   const nsDisplayListSet& aLists)
 {
   bool useMathMLChar = UseMathMLChar();
   if (!useMathMLChar) {
     // let the base class do everything
     nsMathMLTokenFrame::BuildDisplayList(aBuilder, aDirtyRect, aLists);
   } else {
     DisplayBorderBackgroundOutline(aBuilder, aLists);
     // make our char selected if our inner child text frame is selected
     bool isSelected = false;
     nsRect selectedRect;
     nsIFrame* firstChild = mFrames.FirstChild();
     if (IsFrameInSelection(firstChild)) {
       mMathMLChar.GetRect(selectedRect);
       // add a one pixel border (it renders better for operators like minus)
       selectedRect.Inflate(nsPresContext::CSSPixelsToAppUnits(1));
       isSelected = true;
     }
     mMathMLChar.Display(aBuilder, this, aLists, 0, isSelected ? &selectedRect : nullptr);
 #if defined(DEBUG) && defined(SHOW_BOUNDING_BOX)
     // for visual debug
     DisplayBoundingMetrics(aBuilder, this, mReference, mBoundingMetrics, aLists);
 #endif
   }
 }
 // get the text that we enclose and setup our nsMathMLChar
 void
 nsMathMLmoFrame::ProcessTextData()
 {
   mFlags = 0;
   nsAutoString data;
   if (!nsContentUtils::GetNodeTextContent(mContent, false, data)) {
     NS_RUNTIMEABORT("OOM");
   }
   data.CompressWhitespace();
   int32_t length = data.Length();
   char16_t ch = (length == 0) ? char16_t('\0') : data[0];
   if ((length == 1) &&
       (ch == kApplyFunction  ||
        ch == kInvisibleSeparator ||
        ch == kInvisiblePlus ||
        ch == kInvisibleTimes)) {
     mFlags |= NS_MATHML_OPERATOR_INVISIBLE;
   }
   // don't bother doing anything special if we don't have a single child
   nsPresContext* presContext = PresContext();
   if (mFrames.GetLength() != 1) {
     data.Truncate(); // empty data to reset the char
     mMathMLChar.SetData(presContext, data);
     ResolveMathMLCharStyle(presContext, mContent, mStyleContext, &mMathMLChar);
     return;
   }
   // special... in math mode, the usual minus sign '-' looks too short, so
   // what we do here is to remap <mo>-</mo> to the official Unicode minus
   // sign (U+2212) which looks much better. For background on this, see
   // http://groups.google.com/groups?hl=en&th=66488daf1ade7635&rnum=1
   if (1 == length && ch == '-') {
     ch = 0x2212;
     data = ch;
   }
   // cache the special bits: mutable, accent, movablelimits, centered.
   // we need to do this in anticipation of other requirements, and these
   // bits don't change. Do not reset these bits unless the text gets changed.
   // lookup all the forms under which the operator is listed in the dictionary,
   // and record whether the operator has accent="true" or movablelimits="true"
   nsOperatorFlags flags[4];
   float lspace[4], rspace[4];
   nsMathMLOperators::LookupOperators(data, flags, lspace, rspace);
   nsOperatorFlags allFlags =
     flags[NS_MATHML_OPERATOR_FORM_INFIX] |
     flags[NS_MATHML_OPERATOR_FORM_POSTFIX] |
     flags[NS_MATHML_OPERATOR_FORM_PREFIX];
   mFlags |= allFlags & NS_MATHML_OPERATOR_ACCENT;
   mFlags |= allFlags & NS_MATHML_OPERATOR_MOVABLELIMITS;
   // see if this is an operator that should be centered to cater for
   // fonts that are not math-aware
   if (1 == length) {
     if ((ch == '+') || (ch == '=') || (ch == '*') ||
         (ch == 0x2212) || // &minus;
         (ch == 0x2264) || // &le;
         (ch == 0x2265) || // &ge;
         (ch == 0x00D7)) { // &times;
       mFlags |= NS_MATHML_OPERATOR_CENTERED;
     }
   }
   // cache the operator
   mMathMLChar.SetData(presContext, data);
   // cache the native direction -- beware of bug 133429...
   // mEmbellishData.direction must always retain our native direction, whereas
   // mMathMLChar.GetStretchDirection() may change later, when Stretch() is called
   mEmbellishData.direction = mMathMLChar.GetStretchDirection();
   bool isMutable =
     NS_MATHML_OPERATOR_IS_LARGEOP(allFlags) ||
     (mEmbellishData.direction != NS_STRETCH_DIRECTION_UNSUPPORTED);
   if (isMutable)
     mFlags |= NS_MATHML_OPERATOR_MUTABLE;
   ResolveMathMLCharStyle(presContext, mContent, mStyleContext, &mMathMLChar);
 }
 // get our 'form' and lookup in the Operator Dictionary to fetch
 // our default data that may come from there. Then complete our setup
 // using attributes that we may have. To stay in sync, this function is
 // called very often. We depend on many things that may change around us.
 // However, we re-use unchanged values.
 void
 nsMathMLmoFrame::ProcessOperatorData()
 {
   // if we have been here before, we will just use our cached form
   nsOperatorFlags form = NS_MATHML_OPERATOR_GET_FORM(mFlags);
   nsAutoString value;
   // special bits are always kept in mFlags.
   // remember the mutable bit from ProcessTextData().
   // Some chars are listed under different forms in the dictionary,
   // and there could be a form under which the char is mutable.
   // If the char is the core of an embellished container, we will keep
   // it mutable irrespective of the form of the embellished container.
   // Also remember the other special bits that we want to carry forward.
   mFlags &= NS_MATHML_OPERATOR_MUTABLE |
             NS_MATHML_OPERATOR_ACCENT |
             NS_MATHML_OPERATOR_MOVABLELIMITS |
             NS_MATHML_OPERATOR_CENTERED |
             NS_MATHML_OPERATOR_INVISIBLE;
   if (!mEmbellishData.coreFrame) {
     // i.e., we haven't been here before, the default form is infix
     form = NS_MATHML_OPERATOR_FORM_INFIX;
     // reset everything so that we don't keep outdated values around
     // in case of dynamic changes
     mEmbellishData.flags = 0;
     mEmbellishData.coreFrame = nullptr;
     mEmbellishData.leadingSpace = 0;
     mEmbellishData.trailingSpace = 0;
     if (mMathMLChar.Length() != 1)
       mEmbellishData.direction = NS_STRETCH_DIRECTION_UNSUPPORTED;
     // else... retain the native direction obtained in ProcessTextData()
     if (!mFrames.FirstChild()) {
       return;
     }
     mEmbellishData.flags |= NS_MATHML_EMBELLISH_OPERATOR;
     mEmbellishData.coreFrame = this;
     // there are two particular things that we also need to record so that if our
     // parent is <mover>, <munder>, or <munderover>, they will treat us properly:
     // 1) do we have accent="true"
     // 2) do we have movablelimits="true"
     // they need the extra information to decide how to treat their scripts/limits
     // (note: <mover>, <munder>, or <munderover> need not necessarily be our
     // direct parent -- case of embellished operators)
     // default values from the Operator Dictionary were obtained in ProcessTextData()
     // and these special bits are always kept in mFlags
     if (NS_MATHML_OPERATOR_IS_ACCENT(mFlags))
       mEmbellishData.flags |= NS_MATHML_EMBELLISH_ACCENT;
     if (NS_MATHML_OPERATOR_IS_MOVABLELIMITS(mFlags))
       mEmbellishData.flags |= NS_MATHML_EMBELLISH_MOVABLELIMITS;
     // see if the accent attribute is there
     mContent->GetAttr(kNameSpaceID_None, nsGkAtoms::accent_, value);
     if (value.EqualsLiteral("true"))
       mEmbellishData.flags |= NS_MATHML_EMBELLISH_ACCENT;
     else if (value.EqualsLiteral("false"))
       mEmbellishData.flags &= ~NS_MATHML_EMBELLISH_ACCENT;
     // see if the movablelimits attribute is there
     mContent->GetAttr(kNameSpaceID_None, nsGkAtoms::movablelimits_, value);
     if (value.EqualsLiteral("true"))
       mEmbellishData.flags |= NS_MATHML_EMBELLISH_MOVABLELIMITS;
     else if (value.EqualsLiteral("false"))
       mEmbellishData.flags &= ~NS_MATHML_EMBELLISH_MOVABLELIMITS;
      // ---------------------------------------------------------------------
      // we will be called again to re-sync the rest of our state next time...
      // (nobody needs the other values below at this stage)
      mFlags |= form;
      return;
   }
   nsPresContext* presContext = PresContext();
   // beware of bug 133814 - there is a two-way dependency in the
   // embellished hierarchy: our embellished ancestors need to set
   // their flags based on some of our state (set above), and here we
   // need to re-sync our 'form' depending on our outermost embellished
   // container. A null form here means that an earlier attempt to stretch
   // our mMathMLChar failed, in which case we don't bother re-stretching again
   if (form) {
     // get our outermost embellished container and its parent.
     // (we ensure that we are the core, not just a sibling of the core)
     nsIFrame* embellishAncestor = this;
     nsEmbellishData embellishData;
     nsIFrame* parentAncestor = this;
     do {
       embellishAncestor = parentAncestor;
       parentAncestor = embellishAncestor->GetParent();
       GetEmbellishDataFrom(parentAncestor, embellishData);
     } while (embellishData.coreFrame == this);
     // flag if we have an embellished ancestor
     if (embellishAncestor != this)
       mFlags |= NS_MATHML_OPERATOR_EMBELLISH_ANCESTOR;
     else
       mFlags &= ~NS_MATHML_OPERATOR_EMBELLISH_ANCESTOR;
     // find the position of our outermost embellished container w.r.t
     // its siblings.
     nsIFrame* nextSibling = embellishAncestor->GetNextSibling();
     nsIFrame* prevSibling = embellishAncestor->GetPrevSibling();
     // flag to distinguish from a real infix.  Set for (embellished) operators
     // that live in (inferred) mrows.
     nsIMathMLFrame* mathAncestor = do_QueryFrame(parentAncestor);
     bool zeroSpacing = false;
     if (mathAncestor) {
       zeroSpacing =  !mathAncestor->IsMrowLike();
     } else {
       nsMathMLmathBlockFrame* blockFrame = do_QueryFrame(parentAncestor);
       if (blockFrame) {
         zeroSpacing = !blockFrame->IsMrowLike();
       }
     }
     if (zeroSpacing) {
       mFlags |= NS_MATHML_OPERATOR_EMBELLISH_ISOLATED;
     } else {
       mFlags &= ~NS_MATHML_OPERATOR_EMBELLISH_ISOLATED;
     }
     // find our form
     form = NS_MATHML_OPERATOR_FORM_INFIX;
     mContent->GetAttr(kNameSpaceID_None, nsGkAtoms::form, value);
     if (!value.IsEmpty()) {
       if (value.EqualsLiteral("prefix"))
         form = NS_MATHML_OPERATOR_FORM_PREFIX;
       else if (value.EqualsLiteral("postfix"))
         form = NS_MATHML_OPERATOR_FORM_POSTFIX;
     }
     else {
       // set our form flag depending on the position
       if (!prevSibling && nextSibling)
         form = NS_MATHML_OPERATOR_FORM_PREFIX;
       else if (prevSibling && !nextSibling)
         form = NS_MATHML_OPERATOR_FORM_POSTFIX;
     }
     mFlags &= ~NS_MATHML_OPERATOR_FORM; // clear the old form bits
     mFlags |= form;
     // Use the default value suggested by the MathML REC.
     // http://www.w3.org/TR/MathML/chapter3.html#presm.mo.attrs
     // thickmathspace = 5/18em
     float lspace = 5.0f/18.0f;
     float rspace = 5.0f/18.0f;
     // lookup the operator dictionary
     nsAutoString data;
     mMathMLChar.GetData(data);
     nsMathMLOperators::LookupOperator(data, form, &mFlags, &lspace, &rspace);
     // Spacing is zero if our outermost embellished operator is not in an
     // inferred mrow.
     if (!NS_MATHML_OPERATOR_EMBELLISH_IS_ISOLATED(mFlags) &&
         (lspace || rspace)) {
       // Cache the default values of lspace and rspace.
       // since these values are relative to the 'em' unit, convert to twips now
       nscoord em;
       nsRefPtr<nsFontMetrics> fm;
       nsLayoutUtils::GetFontMetricsForFrame(this, getter_AddRefs(fm));
       GetEmHeight(fm, em);
       mEmbellishData.leadingSpace = NSToCoordRound(lspace * em);
       mEmbellishData.trailingSpace = NSToCoordRound(rspace * em);
       // tuning if we don't want too much extra space when we are a script.
       // (with its fonts, TeX sets lspace=0 & rspace=0 as soon as scriptlevel>0.
       // Our fonts can be anything, so...)
       if (StyleFont()->mScriptLevel > 0 &&
           !NS_MATHML_OPERATOR_HAS_EMBELLISH_ANCESTOR(mFlags)) {
         mEmbellishData.leadingSpace /= 2;
         mEmbellishData.trailingSpace /= 2;
       }
     }
   }
   // If we are an accent without explicit lspace="." or rspace=".",
   // we will ignore our default leading/trailing space
   // lspace
   //
   // "Specifies the leading space appearing before the operator"
   //
   // values: length
   // default: set by dictionary (thickmathspace)
   //
   // XXXfredw Support for negative and relative values is not implemented
   // (bug 805926).
   // Relative values will give a multiple of the current leading space,
   // which is not necessarily the default one.
   //
   nscoord leadingSpace = mEmbellishData.leadingSpace;
   mContent->GetAttr(kNameSpaceID_None, nsGkAtoms::lspace_, value);
   if (!value.IsEmpty()) {
     nsCSSValue cssValue;
     if (nsMathMLElement::ParseNumericValue(value, cssValue, 0,
                                            mContent->OwnerDoc())) {
       if ((eCSSUnit_Number == cssValue.GetUnit()) && !cssValue.GetFloatValue())
         leadingSpace = 0;
       else if (cssValue.IsLengthUnit())
         leadingSpace = CalcLength(presContext, mStyleContext, cssValue);
       mFlags |= NS_MATHML_OPERATOR_LSPACE_ATTR;
     }
   }
   // rspace
   //
   // "Specifies the trailing space appearing after the operator"
   //
   // values: length
   // default: set by dictionary (thickmathspace)
   //
   // XXXfredw Support for negative and relative values is not implemented
   // (bug 805926).
   // Relative values will give a multiple of the current leading space,
   // which is not necessarily the default one.
   //
   nscoord trailingSpace = mEmbellishData.trailingSpace;
   mContent->GetAttr(kNameSpaceID_None, nsGkAtoms::rspace_, value);
   if (!value.IsEmpty()) {
     nsCSSValue cssValue;
     if (nsMathMLElement::ParseNumericValue(value, cssValue, 0,
                                            mContent->OwnerDoc())) {
       if ((eCSSUnit_Number == cssValue.GetUnit()) && !cssValue.GetFloatValue())
         trailingSpace = 0;
       else if (cssValue.IsLengthUnit())
         trailingSpace = CalcLength(presContext, mStyleContext, cssValue);
       mFlags |= NS_MATHML_OPERATOR_RSPACE_ATTR;
     }
   }
   // little extra tuning to round lspace & rspace to at least a pixel so that
   // operators don't look as if they are colliding with their operands
   if (leadingSpace || trailingSpace) {
     nscoord onePixel = nsPresContext::CSSPixelsToAppUnits(1);
     if (leadingSpace && leadingSpace < onePixel)
       leadingSpace = onePixel;
     if (trailingSpace && trailingSpace < onePixel)
       trailingSpace = onePixel;
   }
   // the values that we get from our attributes override the dictionary
   mEmbellishData.leadingSpace = leadingSpace;
   mEmbellishData.trailingSpace = trailingSpace;
   // Now see if there are user-defined attributes that override the dictionary.
   // XXX If an attribute can be forced to be true when it is false in the
   // dictionary, then the following code has to change...
   // For each attribute overriden by the user, turn off its bit flag.
   // symmetric|movablelimits|separator|largeop|accent|fence|stretchy|form
   // special: accent and movablelimits are handled above,
   // don't process them here
   mContent->GetAttr(kNameSpaceID_None, nsGkAtoms::stretchy_, value);
   if (value.EqualsLiteral("false")) {
     mFlags &= ~NS_MATHML_OPERATOR_STRETCHY;
   } else if (value.EqualsLiteral("true")) {
     mFlags |= NS_MATHML_OPERATOR_STRETCHY;
   }
   if (NS_MATHML_OPERATOR_IS_FENCE(mFlags)) {
     mContent->GetAttr(kNameSpaceID_None, nsGkAtoms::fence_, value);
     if (value.EqualsLiteral("false"))
       mFlags &= ~NS_MATHML_OPERATOR_FENCE;
   }
   mContent->GetAttr(kNameSpaceID_None, nsGkAtoms::largeop_, value);
   if (value.EqualsLiteral("false")) {
     mFlags &= ~NS_MATHML_OPERATOR_LARGEOP;
   } else if (value.EqualsLiteral("true")) {
     mFlags |= NS_MATHML_OPERATOR_LARGEOP;
   }
   if (NS_MATHML_OPERATOR_IS_SEPARATOR(mFlags)) {
     mContent->GetAttr(kNameSpaceID_None, nsGkAtoms::separator_, value);
     if (value.EqualsLiteral("false"))
       mFlags &= ~NS_MATHML_OPERATOR_SEPARATOR;
   }
   mContent->GetAttr(kNameSpaceID_None, nsGkAtoms::symmetric_, value);
   if (value.EqualsLiteral("false"))
     mFlags &= ~NS_MATHML_OPERATOR_SYMMETRIC;
   else if (value.EqualsLiteral("true"))
     mFlags |= NS_MATHML_OPERATOR_SYMMETRIC;
   // minsize
   //
   // "Specifies the minimum size of the operator when stretchy"
   //
   // values: length
   // default: set by dictionary (1em)
   //
   // We don't allow negative values.
   // Note: Contrary to other "length" values, unitless and percentage do not
   // give a multiple of the defaut value but a multiple of the operator at
   // normal size.
   //
   mMinSize = 0;
   mContent->GetAttr(kNameSpaceID_None, nsGkAtoms::minsize_, value);
   if (!value.IsEmpty()) {
     nsCSSValue cssValue;
     if (nsMathMLElement::ParseNumericValue(value, cssValue,
                                            nsMathMLElement::
                                            PARSE_ALLOW_UNITLESS,
                                            mContent->OwnerDoc())) {
       nsCSSUnit unit = cssValue.GetUnit();
       if (eCSSUnit_Number == unit)
         mMinSize = cssValue.GetFloatValue();
       else if (eCSSUnit_Percent == unit)
         mMinSize = cssValue.GetPercentValue();
       else if (eCSSUnit_Null != unit) {
         mMinSize = float(CalcLength(presContext, mStyleContext, cssValue));
         mFlags |= NS_MATHML_OPERATOR_MINSIZE_ABSOLUTE;
       }
     }
   }
   // maxsize
   //
   // "Specifies the maximum size of the operator when stretchy"
   //
   // values: length | "infinity"
   // default: set by dictionary (infinity)
   //
   // We don't allow negative values.
   // Note: Contrary to other "length" values, unitless and percentage do not
   // give a multiple of the defaut value but a multiple of the operator at
   // normal size.
   //
   mMaxSize = NS_MATHML_OPERATOR_SIZE_INFINITY;
   mContent->GetAttr(kNameSpaceID_None, nsGkAtoms::maxsize_, value);
   if (!value.IsEmpty()) {
     nsCSSValue cssValue;
     if (nsMathMLElement::ParseNumericValue(value, cssValue,
                                            nsMathMLElement::
                                            PARSE_ALLOW_UNITLESS,
                                            mContent->OwnerDoc())) {
       nsCSSUnit unit = cssValue.GetUnit();
       if (eCSSUnit_Number == unit)
         mMaxSize = cssValue.GetFloatValue();
       else if (eCSSUnit_Percent == unit)
         mMaxSize = cssValue.GetPercentValue();
       else if (eCSSUnit_Null != unit) {
         mMaxSize = float(CalcLength(presContext, mStyleContext, cssValue));
         mFlags |= NS_MATHML_OPERATOR_MAXSIZE_ABSOLUTE;
       }
     }
   }
 }
 static uint32_t
 GetStretchHint(nsOperatorFlags aFlags, nsPresentationData aPresentationData,
                bool aIsVertical, const nsStyleFont* aStyleFont)
 {
   uint32_t stretchHint = NS_STRETCH_NONE;
   // See if it is okay to stretch,
   // starting from what the Operator Dictionary said
   if (NS_MATHML_OPERATOR_IS_MUTABLE(aFlags)) {
     // set the largeop or largeopOnly flags to suitably cover all the
     // 8 possible cases depending on whether displaystyle, largeop,
     // stretchy are true or false (see bug 69325).
     // . largeopOnly is taken if largeop=true and stretchy=false
     // . largeop is taken if largeop=true and stretchy=true
     if (aStyleFont->mMathDisplay == NS_MATHML_DISPLAYSTYLE_BLOCK &&
         NS_MATHML_OPERATOR_IS_LARGEOP(aFlags)) {
       stretchHint = NS_STRETCH_LARGEOP; // (largeopOnly, not mask!)
       if (NS_MATHML_OPERATOR_IS_INTEGRAL(aFlags)) {
         stretchHint |= NS_STRETCH_INTEGRAL;
       }
       if (NS_MATHML_OPERATOR_IS_STRETCHY(aFlags)) {
         stretchHint |= NS_STRETCH_NEARER | NS_STRETCH_LARGER;
       }
     }
     else if(NS_MATHML_OPERATOR_IS_STRETCHY(aFlags)) {
       if (aIsVertical) {
         // TeX hint. Can impact some sloppy markups missing <mrow></mrow>
         stretchHint = NS_STRETCH_NEARER;
       }
       else {
         stretchHint = NS_STRETCH_NORMAL;
       }
     }
     // else if the stretchy and largeop attributes have been disabled,
     // the operator is not mutable
   }
   return stretchHint;
 }
 // NOTE: aDesiredStretchSize is an IN/OUT parameter
 //       On input  - it contains our current size
 //       On output - the same size or the new size that we want
 NS_IMETHODIMP
 nsMathMLmoFrame::Stretch(nsRenderingContext& aRenderingContext,
                          nsStretchDirection   aStretchDirection,
                          nsBoundingMetrics&   aContainerSize,
                          nsHTMLReflowMetrics& aDesiredStretchSize)
 {
   if (NS_MATHML_STRETCH_WAS_DONE(mPresentationData.flags)) {
     NS_WARNING("it is wrong to fire stretch more than once on a frame");
     return NS_OK;
   }
   mPresentationData.flags |= NS_MATHML_STRETCH_DONE;
   nsIFrame* firstChild = mFrames.FirstChild();
   // get the axis height;
   nsRefPtr<nsFontMetrics> fm;
   nsLayoutUtils::GetFontMetricsForFrame(this, getter_AddRefs(fm));
   aRenderingContext.SetFont(fm);
   nscoord axisHeight, height;
   GetAxisHeight(aRenderingContext, fm, axisHeight);
   // get the leading to be left at the top and the bottom of the stretched char
   // this seems more reliable than using fm->GetLeading() on suspicious fonts
   nscoord em;
   GetEmHeight(fm, em);
   nscoord leading = NSToCoordRound(0.2f * em);
   // Operators that are stretchy, or those that are to be centered
   // to cater for fonts that are not math-aware, are handled by the MathMLChar
   // ('form' is reset if stretch fails -- i.e., we don't bother to stretch next time)
   bool useMathMLChar = UseMathMLChar();
   nsBoundingMetrics charSize;
   nsBoundingMetrics container = aDesiredStretchSize.mBoundingMetrics;
   bool isVertical = false;
   if (((aStretchDirection == NS_STRETCH_DIRECTION_VERTICAL) ||
        (aStretchDirection == NS_STRETCH_DIRECTION_DEFAULT))  &&
       (mEmbellishData.direction == NS_STRETCH_DIRECTION_VERTICAL)) {
     isVertical = true;
   }
   uint32_t stretchHint =
     GetStretchHint(mFlags, mPresentationData, isVertical, StyleFont());
   if (useMathMLChar) {
     nsBoundingMetrics initialSize = aDesiredStretchSize.mBoundingMetrics;
     if (stretchHint != NS_STRETCH_NONE) {
       container = aContainerSize;
       // some adjustments if the operator is symmetric and vertical
       if (isVertical && NS_MATHML_OPERATOR_IS_SYMMETRIC(mFlags)) {
         // we need to center about the axis
         nscoord delta = std::max(container.ascent - axisHeight,
                                container.descent + axisHeight);
         container.ascent = delta + axisHeight;
         container.descent = delta - axisHeight;
         // get ready in case we encounter user-desired min-max size
         delta = std::max(initialSize.ascent - axisHeight,
                        initialSize.descent + axisHeight);
         initialSize.ascent = delta + axisHeight;
         initialSize.descent = delta - axisHeight;
       }
       // check for user-desired min-max size
       if (mMaxSize != NS_MATHML_OPERATOR_SIZE_INFINITY && mMaxSize > 0.0f) {
         // if we are here, there is a user defined maxsize ...
         //XXX Set stretchHint = NS_STRETCH_NORMAL? to honor the maxsize as close as possible?
         if (NS_MATHML_OPERATOR_MAXSIZE_IS_ABSOLUTE(mFlags)) {
           // there is an explicit value like maxsize="20pt"
           // try to maintain the aspect ratio of the char
           float aspect = mMaxSize / float(initialSize.ascent + initialSize.descent);
           container.ascent =
             std::min(container.ascent, nscoord(initialSize.ascent * aspect));
           container.descent =
             std::min(container.descent, nscoord(initialSize.descent * aspect));
           // below we use a type cast instead of a conversion to avoid a VC++ bug
           // see http://support.microsoft.com/support/kb/articles/Q115/7/05.ASP
           container.width =
             std::min(container.width, (nscoord)mMaxSize);
         }
         else { // multiplicative value
           container.ascent =
             std::min(container.ascent, nscoord(initialSize.ascent * mMaxSize));
           container.descent =
             std::min(container.descent, nscoord(initialSize.descent * mMaxSize));
           container.width =
             std::min(container.width, nscoord(initialSize.width * mMaxSize));
         }
         if (isVertical && !NS_MATHML_OPERATOR_IS_SYMMETRIC(mFlags)) {
           // re-adjust to align the char with the bottom of the initial container
           height = container.ascent + container.descent;
           container.descent = aContainerSize.descent;
           container.ascent = height - container.descent;
         }
       }
       if (mMinSize > 0.0f) {
         // if we are here, there is a user defined minsize ...
         // always allow the char to stretch in its natural direction,
         // even if it is different from the caller's direction
         if (aStretchDirection != NS_STRETCH_DIRECTION_DEFAULT &&
             aStretchDirection != mEmbellishData.direction) {
           aStretchDirection = NS_STRETCH_DIRECTION_DEFAULT;
           // but when we are not honoring the requested direction
           // we should not use the caller's container size either
           container = initialSize;
         }
         if (NS_MATHML_OPERATOR_MINSIZE_IS_ABSOLUTE(mFlags)) {
           // there is an explicit value like minsize="20pt"
           // try to maintain the aspect ratio of the char
           float aspect = mMinSize / float(initialSize.ascent + initialSize.descent);
           container.ascent =
             std::max(container.ascent, nscoord(initialSize.ascent * aspect));
           container.descent =
             std::max(container.descent, nscoord(initialSize.descent * aspect));
           container.width =
             std::max(container.width, (nscoord)mMinSize);
         }
         else { // multiplicative value
           container.ascent =
             std::max(container.ascent, nscoord(initialSize.ascent * mMinSize));
           container.descent =
             std::max(container.descent, nscoord(initialSize.descent * mMinSize));
           container.width =
             std::max(container.width, nscoord(initialSize.width * mMinSize));
         }
         if (isVertical && !NS_MATHML_OPERATOR_IS_SYMMETRIC(mFlags)) {
           // re-adjust to align the char with the bottom of the initial container
           height = container.ascent + container.descent;
           container.descent = aContainerSize.descent;
           container.ascent = height - container.descent;
         }
       }
     }
     // let the MathMLChar stretch itself...
     nsresult res = mMathMLChar.Stretch(PresContext(), aRenderingContext,
                                        aStretchDirection, container, charSize,
                                        stretchHint,
                                        StyleVisibility()->mDirection);
     if (NS_FAILED(res)) {
       // gracefully handle cases where stretching the char failed (i.e., GetBoundingMetrics failed)
       // clear our 'form' to behave as if the operator wasn't in the dictionary
       mFlags &= ~NS_MATHML_OPERATOR_FORM;
       useMathMLChar = false;
     }
   }
   // Place our children using the default method
   // This will allow our child text frame to get its DidReflow()
   nsresult rv = Place(aRenderingContext, true, aDesiredStretchSize);
   if (NS_MATHML_HAS_ERROR(mPresentationData.flags) || NS_FAILED(rv)) {
     // Make sure the child frames get their DidReflow() calls.
     DidReflowChildren(mFrames.FirstChild());
   }
   if (useMathMLChar) {
     // update our bounding metrics... it becomes that of our MathML char
     mBoundingMetrics = charSize;
     // if the returned direction is 'unsupported', the char didn't actually change.
     // So we do the centering only if necessary
     if (mMathMLChar.GetStretchDirection() != NS_STRETCH_DIRECTION_UNSUPPORTED ||
         NS_MATHML_OPERATOR_IS_CENTERED(mFlags)) {
       bool largeopOnly =
         (NS_STRETCH_LARGEOP & stretchHint) != 0 &&
         (NS_STRETCH_VARIABLE_MASK & stretchHint) == 0;
       if (isVertical || NS_MATHML_OPERATOR_IS_CENTERED(mFlags)) {
         // the desired size returned by mMathMLChar maybe different
         // from the size of the container.
         // the mMathMLChar.mRect.y calculation is subtle, watch out!!!
         height = mBoundingMetrics.ascent + mBoundingMetrics.descent;
         if (NS_MATHML_OPERATOR_IS_SYMMETRIC(mFlags) ||
             NS_MATHML_OPERATOR_IS_CENTERED(mFlags)) {
           // For symmetric and vertical operators, or for operators that are always
           // centered ('+', '*', etc) we want to center about the axis of the container
           mBoundingMetrics.descent = height/2 - axisHeight;
         } else if (!largeopOnly) {
           // Align the center of the char with the center of the container
           mBoundingMetrics.descent = height/2 +
             (container.ascent + container.descent)/2 - container.ascent;
         } // else align the baselines
         mBoundingMetrics.ascent = height - mBoundingMetrics.descent;
       }
     }
   }
   // Fixup for the final height.
   // On one hand, our stretchy height can sometimes be shorter than surrounding
   // ASCII chars, e.g., arrow symbols have |mBoundingMetrics.ascent + leading|
   // that is smaller than the ASCII's ascent, hence when painting the background
   // later, it won't look uniform along the line.
   // On the other hand, sometimes we may leave too much gap when our glyph happens
   // to come from a font with tall glyphs. For example, since CMEX10 has very tall
   // glyphs, its natural font metrics are large, even if we pick a small glyph
   // whose size is comparable to the size of a normal ASCII glyph.
   // So to avoid uneven spacing in either of these two cases, we use the height
   // of the ASCII font as a reference and try to match it if possible.
   // special case for accents... keep them short to improve mouse operations...
   // an accent can only be the non-first child of <mover>, <munder>, <munderover>
   bool isAccent =
     NS_MATHML_EMBELLISH_IS_ACCENT(mEmbellishData.flags);
   if (isAccent) {
     nsEmbellishData parentData;
     GetEmbellishDataFrom(mParent, parentData);
     isAccent =
        (NS_MATHML_EMBELLISH_IS_ACCENTOVER(parentData.flags) ||
         NS_MATHML_EMBELLISH_IS_ACCENTUNDER(parentData.flags)) &&
        parentData.coreFrame != this;
   }
   if (isAccent && firstChild) {
     // see bug 188467 for what is going on here
     nscoord dy = aDesiredStretchSize.TopAscent() - (mBoundingMetrics.ascent + leading);
     aDesiredStretchSize.SetTopAscent(mBoundingMetrics.ascent + leading);
     aDesiredStretchSize.Height() = aDesiredStretchSize.TopAscent() + mBoundingMetrics.descent;
     firstChild->SetPosition(firstChild->GetPosition() - nsPoint(0, dy));
   }
   else if (useMathMLChar) {
     nscoord ascent = fm->MaxAscent();
     nscoord descent = fm->MaxDescent();
     aDesiredStretchSize.SetTopAscent(std::max(mBoundingMetrics.ascent + leading, ascent));
     aDesiredStretchSize.Height() = aDesiredStretchSize.TopAscent() +
                                  std::max(mBoundingMetrics.descent + leading, descent);
   }
   aDesiredStretchSize.Width() = mBoundingMetrics.width;
   aDesiredStretchSize.mBoundingMetrics = mBoundingMetrics;
   mReference.x = 0;
   mReference.y = aDesiredStretchSize.TopAscent();
   // Place our mMathMLChar, its origin is in our coordinate system
   if (useMathMLChar) {
     nscoord dy = aDesiredStretchSize.TopAscent() - mBoundingMetrics.ascent;
     mMathMLChar.SetRect(nsRect(0, dy, charSize.width, charSize.ascent + charSize.descent));
   }
   // Before we leave... there is a last item in the check-list:
   // If our parent is not embellished, it means we are the outermost embellished
   // container and so we put the spacing, otherwise we don't include the spacing,
   // the outermost embellished container will take care of it.
   if (!NS_MATHML_OPERATOR_HAS_EMBELLISH_ANCESTOR(mFlags)) {
     // Account the spacing if we are not an accent with explicit attributes
     nscoord leadingSpace = mEmbellishData.leadingSpace;
     if (isAccent && !NS_MATHML_OPERATOR_HAS_LSPACE_ATTR(mFlags)) {
       leadingSpace = 0;
     }
     nscoord trailingSpace = mEmbellishData.trailingSpace;
     if (isAccent && !NS_MATHML_OPERATOR_HAS_RSPACE_ATTR(mFlags)) {
       trailingSpace = 0;
     }
     mBoundingMetrics.width += leadingSpace + trailingSpace;
     aDesiredStretchSize.Width() = mBoundingMetrics.width;
     aDesiredStretchSize.mBoundingMetrics.width = mBoundingMetrics.width;
     nscoord dx = (StyleVisibility()->mDirection ?
                   trailingSpace : leadingSpace);
     if (dx) {
       // adjust the offsets
       mBoundingMetrics.leftBearing += dx;
       mBoundingMetrics.rightBearing += dx;
       aDesiredStretchSize.mBoundingMetrics.leftBearing += dx;
       aDesiredStretchSize.mBoundingMetrics.rightBearing += dx;
       if (useMathMLChar) {
         nsRect rect;
         mMathMLChar.GetRect(rect);
         mMathMLChar.SetRect(nsRect(rect.x + dx, rect.y,
                                    rect.width, rect.height));
       }
       else {
         nsIFrame* childFrame = firstChild;
         while (childFrame) {
           childFrame->SetPosition(childFrame->GetPosition() +
                                   nsPoint(dx, 0));
           childFrame = childFrame->GetNextSibling();
         }
       }
     }
   }
   // Finished with these:
   ClearSavedChildMetrics();
   // Set our overflow area
   GatherAndStoreOverflow(&aDesiredStretchSize);
   // There used to be code here to change the height of the child frame to
   // change the caret height, but the text frame that manages the caret is now
   // not a direct child but wrapped in a block frame.  See also bug 412033.
   return NS_OK;
 }
 NS_IMETHODIMP
 nsMathMLmoFrame::InheritAutomaticData(nsIFrame* aParent)
 {
   // retain our native direction, it only changes if our text content changes
   nsStretchDirection direction = mEmbellishData.direction;
   nsMathMLTokenFrame::InheritAutomaticData(aParent);
   ProcessTextData();
   mEmbellishData.direction = direction;
   return NS_OK;
 }
 NS_IMETHODIMP
 nsMathMLmoFrame::TransmitAutomaticData()
 {
   // this will cause us to re-sync our flags from scratch
   // but our returned 'form' is still not final (bug 133429), it will
   // be recomputed to its final value during the next call in Reflow()
   mEmbellishData.coreFrame = nullptr;
   ProcessOperatorData();
   return NS_OK;
 }
 nsresult
 nsMathMLmoFrame::SetInitialChildList(ChildListID     aListID,
                                      nsFrameList&    aChildList)
 {
   // First, let the parent class do its work
   nsresult rv = nsMathMLTokenFrame::SetInitialChildList(aListID, aChildList);
   if (NS_FAILED(rv))
     return rv;
   ProcessTextData();
   return rv;
 }
 nsresult
 nsMathMLmoFrame::Reflow(nsPresContext*          aPresContext,
                         nsHTMLReflowMetrics&     aDesiredSize,
                         const nsHTMLReflowState& aReflowState,
                         nsReflowStatus&          aStatus)
 {
   // certain values use units that depend on our style context, so
   // it is safer to just process the whole lot here
   ProcessOperatorData();
   return nsMathMLTokenFrame::Reflow(aPresContext, aDesiredSize,
                                     aReflowState, aStatus);
 }
 /* virtual */ void
 nsMathMLmoFrame::MarkIntrinsicWidthsDirty()
 {
   // if we get this, it may mean that something changed in the text
   // content. So blow away everything an re-build the automatic data
   // from the parent of our outermost embellished container (we ensure
   // that we are the core, not just a sibling of the core)
   ProcessTextData();
   nsIFrame* target = this;
   nsEmbellishData embellishData;
   do {
     target = target->GetParent();
     GetEmbellishDataFrom(target, embellishData);
   } while (embellishData.coreFrame == this);
   // we have automatic data to update in the children of the target frame
   // XXXldb This should really be marking dirty rather than rebuilding
   // so that we don't rebuild multiple times for the same change.
   RebuildAutomaticDataForChildren(target);
   nsMathMLContainerFrame::MarkIntrinsicWidthsDirty();
 }
 /* virtual */ void
 nsMathMLmoFrame::GetIntrinsicWidthMetrics(nsRenderingContext *aRenderingContext, nsHTMLReflowMetrics& aDesiredSize)
 {
   ProcessOperatorData();
   if (UseMathMLChar()) {
     uint32_t stretchHint = GetStretchHint(mFlags, mPresentationData, true,
                                           StyleFont());
     aDesiredSize.Width() = mMathMLChar.
       GetMaxWidth(PresContext(), *aRenderingContext,
                   stretchHint, mMaxSize,
                   NS_MATHML_OPERATOR_MAXSIZE_IS_ABSOLUTE(mFlags));
   }
   else {
     nsMathMLTokenFrame::GetIntrinsicWidthMetrics(aRenderingContext,
                                                  aDesiredSize);
   }
   // leadingSpace and trailingSpace are actually applied to the outermost
   // embellished container but for determining total intrinsic width it should
   // be safe to include it for the core here instead.
   bool isRTL = StyleVisibility()->mDirection;
   aDesiredSize.Width() +=
     mEmbellishData.leadingSpace + mEmbellishData.trailingSpace;
   aDesiredSize.mBoundingMetrics.width = aDesiredSize.Width();
   if (isRTL) {
     aDesiredSize.mBoundingMetrics.leftBearing += mEmbellishData.trailingSpace;
     aDesiredSize.mBoundingMetrics.rightBearing += mEmbellishData.trailingSpace;
   } else {
     aDesiredSize.mBoundingMetrics.leftBearing += mEmbellishData.leadingSpace;
     aDesiredSize.mBoundingMetrics.rightBearing += mEmbellishData.leadingSpace;
   }
 }
 nsresult
 nsMathMLmoFrame::AttributeChanged(int32_t         aNameSpaceID,
                                   nsIAtom*        aAttribute,
                                   int32_t         aModType)
 {
   // check if this is an attribute that can affect the embellished hierarchy
   // in a significant way and re-layout the entire hierarchy.
   if (nsGkAtoms::accent_ == aAttribute ||
       nsGkAtoms::movablelimits_ == aAttribute) {
     // set the target as the parent of our outermost embellished container
     // (we ensure that we are the core, not just a sibling of the core)
     nsIFrame* target = this;
     nsEmbellishData embellishData;
     do {
       target = target->GetParent();
       GetEmbellishDataFrom(target, embellishData);
     } while (embellishData.coreFrame == this);
     // we have automatic data to update in the children of the target frame
     return ReLayoutChildren(target);
   }
   return nsMathMLTokenFrame::
          AttributeChanged(aNameSpaceID, aAttribute, aModType);
 }
 // ----------------------
 // No need to track the style context given to our MathML char.
 // the Style System will use these to pass the proper style context to our MathMLChar
 nsStyleContext*
 nsMathMLmoFrame::GetAdditionalStyleContext(int32_t aIndex) const
 {
   switch (aIndex) {
   case NS_MATHML_CHAR_STYLE_CONTEXT_INDEX:
     return mMathMLChar.GetStyleContext();
   default:
     return nullptr;
   }
 }
 void
 nsMathMLmoFrame::SetAdditionalStyleContext(int32_t          aIndex,
                                            nsStyleContext*  aStyleContext)
 {
   switch (aIndex) {
   case NS_MATHML_CHAR_STYLE_CONTEXT_INDEX:
     mMathMLChar.SetStyleContext(aStyleContext);
     break;
   }
 }

The Tor Browser / annotate

layout/mathml/nsMathMLmoFrame.cpp@b8a032363ba2 (annotated)

layout/mathml/nsMathMLmoFrame.cpp