Quelle nsMathMLContainerFrame.cpp Sprache: C

/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* 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 "nsMathMLContainerFrame.h"

#include "gfxContext.h"
#include "gfxUtils.h"
#include "mozilla/Likely.h"
#include "mozilla/PresShell.h"
#include "mozilla/dom/MutationEventBinding.h"
#include "mozilla/gfx/2D.h"
#include "nsLayoutUtils.h"
#include "nsPresContext.h"
#include "nsNameSpaceManager.h"
#include "nsGkAtoms.h"
#include "nsDisplayList.h"
#include "nsIScriptError.h"
#include "nsContentUtils.h"
#include "mozilla/dom/MathMLElement.h"

using namespace mozilla;
using namespace mozilla::gfx;

//
// nsMathMLContainerFrame implementation
//

NS_QUERYFRAME_HEAD(nsMathMLContainerFrame)
  NS_QUERYFRAME_ENTRY(nsIMathMLFrame)
  NS_QUERYFRAME_ENTRY(nsMathMLContainerFrame)
NS_QUERYFRAME_TAIL_INHERITING(nsContainerFrame)

/* /////////////
* nsIMathMLFrame - support methods for stretchy elements
* =============================================================================
*/

static bool IsForeignChild(const nsIFrame* aFrame) {
  // This counts nsMathMLmathBlockFrame as a foreign child, because it
  // uses block reflow
  return !aFrame->IsMathMLFrame() || aFrame->IsBlockFrame();
}

NS_DECLARE_FRAME_PROPERTY_DELETABLE(HTMLReflowOutputProperty, ReflowOutput)

/* static */
void nsMathMLContainerFrame::SaveReflowAndBoundingMetricsFor(
    nsIFrame* aFrame, const ReflowOutput& aReflowOutput,
    const nsBoundingMetrics& aBoundingMetrics) {
  ReflowOutput* reflowOutput = new ReflowOutput(aReflowOutput);
  reflowOutput->mBoundingMetrics = aBoundingMetrics;
  aFrame->SetProperty(HTMLReflowOutputProperty(), reflowOutput);
}

// helper method to facilitate getting the reflow and bounding metrics
/* static */
void nsMathMLContainerFrame::GetReflowAndBoundingMetricsFor(
    nsIFrame* aFrame, ReflowOutput& aReflowOutput,
    nsBoundingMetrics& aBoundingMetrics, eMathMLFrameType* aMathMLFrameType) {
  MOZ_ASSERT(aFrame, "null arg");

  ReflowOutput* reflowOutput = aFrame->GetProperty(HTMLReflowOutputProperty());

  // IMPORTANT: This function is only meant to be called in Place() methods
  // where it is assumed that SaveReflowAndBoundingMetricsFor has recorded the
  // information.
  NS_ASSERTION(reflowOutput, "Didn't SaveReflowAndBoundingMetricsFor frame!");
  if (reflowOutput) {
    aReflowOutput = *reflowOutput;
    aBoundingMetrics = reflowOutput->mBoundingMetrics;
  }

  if (aMathMLFrameType) {
    if (!IsForeignChild(aFrame)) {
      nsIMathMLFrame* mathMLFrame = do_QueryFrame(aFrame);
      if (mathMLFrame) {
        *aMathMLFrameType = mathMLFrame->GetMathMLFrameType();
        return;
      }
    }
    *aMathMLFrameType = eMathMLFrameType_UNKNOWN;
  }
}

void nsMathMLContainerFrame::ClearSavedChildMetrics() {
  nsIFrame* childFrame = mFrames.FirstChild();
  while (childFrame) {
    childFrame->RemoveProperty(HTMLReflowOutputProperty());
    childFrame = childFrame->GetNextSibling();
  }
}

nsMargin nsMathMLContainerFrame::GetBorderPaddingForPlace(
    const PlaceFlags& aFlags) {
  if (aFlags.contains(PlaceFlag::IgnoreBorderPadding)) {
    return nsMargin();
  }

  if (aFlags.contains(PlaceFlag::IntrinsicSize)) {
    // Bug 1910859: Should we provide separate left and right border/padding?
    return nsMargin(0, IntrinsicISizeOffsets().BorderPadding(), 0, 0);
  }

  return GetUsedBorderAndPadding();
}

/* static */
nsMargin nsMathMLContainerFrame::GetMarginForPlace(const PlaceFlags& aFlags,
                                                   nsIFrame* aChild) {
  if (aFlags.contains(PlaceFlag::IntrinsicSize)) {
    // Bug 1910859: Should we provide separate left and right margin?
    return nsMargin(0, aChild->IntrinsicISizeOffsets().margin, 0, 0);
  }

  return aChild->GetUsedMargin();
}

void nsMathMLContainerFrame::InflateReflowAndBoundingMetrics(
    const nsMargin& aBorderPadding, ReflowOutput& aReflowOutput,
    nsBoundingMetrics& aBoundingMetrics) {
  // Bug 1910858: It is not really clear what is the right way to update the
  // ink bounding box when adding border or padding. Below, we assume that
  // border/padding inflate it.
  aBoundingMetrics.rightBearing += aBorderPadding.LeftRight();
  aBoundingMetrics.width += aBorderPadding.LeftRight();
  aReflowOutput.mBoundingMetrics = aBoundingMetrics;
  aReflowOutput.Width() += aBorderPadding.LeftRight();
  aReflowOutput.SetBlockStartAscent(aReflowOutput.BlockStartAscent() +
                                    aBorderPadding.top);
  aReflowOutput.Height() += aBorderPadding.TopBottom();
}

nsMathMLContainerFrame::WidthAndHeightForPlaceAdjustment
nsMathMLContainerFrame::GetWidthAndHeightForPlaceAdjustment(
    const PlaceFlags& aFlags) {
  WidthAndHeightForPlaceAdjustment sizes;
  if (aFlags.contains(PlaceFlag::DoNotAdjustForWidthAndHeight)) {
    return sizes;
  }
  const nsStylePosition* stylePos = StylePosition();
  const auto& width = stylePos->mWidth;
  // TODO: Resolve percentages.
  // https://github.com/w3c/mathml-core/issues/76
  if (width.ConvertsToLength()) {
    sizes.width = Some(width.ToLength());
  }
  if (!aFlags.contains(PlaceFlag::IntrinsicSize)) {
    // TODO: Resolve percentages.
    // https://github.com/w3c/mathml-core/issues/77
    const auto& height = stylePos->mHeight;
    if (height.ConvertsToLength()) {
      sizes.height = Some(height.ToLength());
    }
  }
  return sizes;
}

nscoord nsMathMLContainerFrame::ApplyAdjustmentForWidthAndHeight(
    const PlaceFlags& aFlags, const WidthAndHeightForPlaceAdjustment& aSizes,
    ReflowOutput& aReflowOutput, nsBoundingMetrics& aBoundingMetrics) {
  nscoord shiftX = 0;
  if (aSizes.width) {
    MOZ_ASSERT(!aFlags.contains(PlaceFlag::DoNotAdjustForWidthAndHeight));
    auto width = *aSizes.width;
    auto oldWidth = aReflowOutput.Width();
    if (IsMathContentBoxHorizontallyCentered()) {
      shiftX = (width - oldWidth) / 2;
    } else if (StyleVisibility()->mDirection == StyleDirection::Rtl) {
      shiftX = width - oldWidth;
    }
    aBoundingMetrics.leftBearing = 0;
    aBoundingMetrics.rightBearing = width;
    aBoundingMetrics.width = width;
    aReflowOutput.mBoundingMetrics = aBoundingMetrics;
    aReflowOutput.Width() = width;
  }
  if (aSizes.height) {
    MOZ_ASSERT(!aFlags.contains(PlaceFlag::DoNotAdjustForWidthAndHeight));
    MOZ_ASSERT(!aFlags.contains(PlaceFlag::IntrinsicSize));
    auto height = *aSizes.height;
    aReflowOutput.Height() = height;
  }
  return shiftX;
}

// helper to get the preferred size that a container frame should use to fire
// the stretch on its stretchy child frames.
void nsMathMLContainerFrame::GetPreferredStretchSize(
    DrawTarget* aDrawTarget, uint32_t aOptions,
    nsStretchDirection aStretchDirection,
    nsBoundingMetrics& aPreferredStretchSize) {
  if (aOptions & STRETCH_CONSIDER_ACTUAL_SIZE) {
    // when our actual size is ok, just use it
    aPreferredStretchSize = mBoundingMetrics;
  } else if (aOptions & STRETCH_CONSIDER_EMBELLISHMENTS) {
    // compute our up-to-date size using Place(), without border/padding.
    ReflowOutput reflowOutput(GetWritingMode());
    PlaceFlags flags(PlaceFlag::MeasureOnly, PlaceFlag::IgnoreBorderPadding);
    Place(aDrawTarget, flags, reflowOutput);
    aPreferredStretchSize = reflowOutput.mBoundingMetrics;
  } else {
    // compute a size that includes embellishments iff the container stretches
    // in the same direction as the embellished operator.
    bool stretchAll = aStretchDirection == NS_STRETCH_DIRECTION_VERTICAL
                          ? NS_MATHML_WILL_STRETCH_ALL_CHILDREN_VERTICALLY(
                                mPresentationData.flags)
                          : NS_MATHML_WILL_STRETCH_ALL_CHILDREN_HORIZONTALLY(
                                mPresentationData.flags);
    NS_ASSERTION(aStretchDirection == NS_STRETCH_DIRECTION_HORIZONTAL ||
                     aStretchDirection == NS_STRETCH_DIRECTION_VERTICAL,
                 "You must specify a direction in which to stretch");
    NS_ASSERTION(
        NS_MATHML_IS_EMBELLISH_OPERATOR(mEmbellishData.flags) || stretchAll,
        "invalid call to GetPreferredStretchSize");
    bool firstTime = true;
    nsBoundingMetrics bm, bmChild;
    nsIFrame* childFrame = stretchAll ? PrincipalChildList().FirstChild()
                                      : mPresentationData.baseFrame;
    while (childFrame) {
      // initializations in case this child happens not to be a MathML frame
      nsIMathMLFrame* mathMLFrame = do_QueryFrame(childFrame);
      if (mathMLFrame) {
        nsEmbellishData embellishData;
        nsPresentationData presentationData;
        mathMLFrame->GetEmbellishData(embellishData);
        mathMLFrame->GetPresentationData(presentationData);
        if (NS_MATHML_IS_EMBELLISH_OPERATOR(embellishData.flags) &&
            embellishData.direction == aStretchDirection &&
            presentationData.baseFrame) {
          // embellishements are not included, only consider the inner first
          // child itself
          // XXXkt Does that mean the core descendent frame should be used
          // instead of the base child?
          nsIMathMLFrame* mathMLchildFrame =
              do_QueryFrame(presentationData.baseFrame);
          if (mathMLchildFrame) {
            mathMLFrame = mathMLchildFrame;
          }
        }
        mathMLFrame->GetBoundingMetrics(bmChild);
      } else {
        ReflowOutput unused(GetWritingMode());
        GetReflowAndBoundingMetricsFor(childFrame, unused, bmChild);
      }

      if (firstTime) {
        firstTime = false;
        bm = bmChild;
        if (!stretchAll) {
          // we may get here for cases such as <msup><mo>...</mo> ... </msup>,
          // or <maction>...<mo>...</mo></maction>.
          break;
        }
      } else {
        if (aStretchDirection == NS_STRETCH_DIRECTION_HORIZONTAL) {
          // if we get here, it means this is container that will stack its
          // children vertically and fire an horizontal stretch on each them.
          // This is the case for \munder, \mover, \munderover. We just sum-up
          // the size vertically.
          bm.descent += bmChild.ascent + bmChild.descent;
          // Sometimes non-spacing marks (when width is zero) are positioned
          // to the left of the origin, but it is the distance between left
          // and right bearing that is important rather than the offsets from
          // the origin.
          if (bmChild.width == 0) {
            bmChild.rightBearing -= bmChild.leftBearing;
            bmChild.leftBearing = 0;
          }
          if (bm.leftBearing > bmChild.leftBearing) {
            bm.leftBearing = bmChild.leftBearing;
          }
          if (bm.rightBearing < bmChild.rightBearing) {
            bm.rightBearing = bmChild.rightBearing;
          }
        } else if (aStretchDirection == NS_STRETCH_DIRECTION_VERTICAL) {
          // just sum-up the sizes horizontally.
          bm += bmChild;
        } else {
          NS_ERROR("unexpected case in GetPreferredStretchSize");
          break;
        }
      }
      childFrame = childFrame->GetNextSibling();
    }
    aPreferredStretchSize = bm;
  }
}

NS_IMETHODIMP
nsMathMLContainerFrame::Stretch(DrawTarget* aDrawTarget,
                                nsStretchDirection aStretchDirection,
                                nsBoundingMetrics& aContainerSize,
                                ReflowOutput& aDesiredStretchSize) {
  if (NS_MATHML_IS_EMBELLISH_OPERATOR(mEmbellishData.flags)) {
    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;

    // Pass the stretch to the base child ...

    nsIFrame* baseFrame = mPresentationData.baseFrame;
    if (baseFrame) {
      nsIMathMLFrame* mathMLFrame = do_QueryFrame(baseFrame);
      NS_ASSERTION(mathMLFrame, "Something is wrong somewhere");
      if (mathMLFrame) {
        // And the trick is that the child's rect.x is still holding the
        // descent, and rect.y is still holding the ascent ...
        ReflowOutput childSize(aDesiredStretchSize);
        GetReflowAndBoundingMetricsFor(baseFrame, childSize,
                                       childSize.mBoundingMetrics);

        // See if we should downsize and confine the stretch to us...
        // XXX there may be other cases where we can downsize the stretch,
        // e.g., the first ∑ might appear big in the following situation
        // <math xmlns='http://www.w3.org/1998/Math/MathML'>
        //   <mstyle>
        //     <msub>
        //        <msub><mo>∑</mo><mfrac><mi>a</mi><mi>b</mi></mfrac></msub>
        //        <msub><mo>∑</mo><mfrac><mi>a</mi><mi>b</mi></mfrac></msub>
        //      </msub>
        //   </mstyle>
        // </math>
        nsBoundingMetrics containerSize = aContainerSize;
        if (aStretchDirection != mEmbellishData.direction &&
            mEmbellishData.direction != NS_STRETCH_DIRECTION_UNSUPPORTED) {
          NS_ASSERTION(
              mEmbellishData.direction != NS_STRETCH_DIRECTION_DEFAULT,
              "Stretches may have a default direction, operators can not.");
          if (mEmbellishData.direction == NS_STRETCH_DIRECTION_VERTICAL
                  ? NS_MATHML_WILL_STRETCH_ALL_CHILDREN_VERTICALLY(
                        mPresentationData.flags)
                  : NS_MATHML_WILL_STRETCH_ALL_CHILDREN_HORIZONTALLY(
                        mPresentationData.flags)) {
            GetPreferredStretchSize(aDrawTarget, 0, mEmbellishData.direction,
                                    containerSize);
            // Stop further recalculations
            aStretchDirection = mEmbellishData.direction;
          } else {
            // We aren't going to stretch the child, so just use the child
            // metrics.
            containerSize = childSize.mBoundingMetrics;
          }
        }

        // do the stretching...
        mathMLFrame->Stretch(aDrawTarget, aStretchDirection, containerSize,
                             childSize);
        // store the updated metrics
        SaveReflowAndBoundingMetricsFor(baseFrame, childSize,
                                        childSize.mBoundingMetrics);

        // Remember the siblings which were _deferred_.
        // Now that this embellished child may have changed, we need to
        // fire the stretch on its siblings using our updated size

        if (NS_MATHML_WILL_STRETCH_ALL_CHILDREN_VERTICALLY(
                mPresentationData.flags) ||
            NS_MATHML_WILL_STRETCH_ALL_CHILDREN_HORIZONTALLY(
                mPresentationData.flags)) {
          nsStretchDirection stretchDir =
              NS_MATHML_WILL_STRETCH_ALL_CHILDREN_VERTICALLY(
                  mPresentationData.flags)
                  ? NS_STRETCH_DIRECTION_VERTICAL
                  : NS_STRETCH_DIRECTION_HORIZONTAL;

          GetPreferredStretchSize(aDrawTarget, STRETCH_CONSIDER_EMBELLISHMENTS,
                                  stretchDir, containerSize);

          nsIFrame* childFrame = mFrames.FirstChild();
          while (childFrame) {
            if (childFrame != mPresentationData.baseFrame) {
              mathMLFrame = do_QueryFrame(childFrame);
              if (mathMLFrame) {
                // retrieve the metrics that was stored at the previous pass
                GetReflowAndBoundingMetricsFor(childFrame, childSize,
                                               childSize.mBoundingMetrics);
                // do the stretching...
                mathMLFrame->Stretch(aDrawTarget, stretchDir, containerSize,
                                     childSize);
                // store the updated metrics
                SaveReflowAndBoundingMetricsFor(childFrame, childSize,
                                                childSize.mBoundingMetrics);
              }
            }
            childFrame = childFrame->GetNextSibling();
          }
        }

        // re-position all our children
        PlaceFlags flags;
        nsresult rv = Place(aDrawTarget, flags, aDesiredStretchSize);
        if (NS_FAILED(rv)) {
          // Make sure the child frames get their DidReflow() calls.
          DidReflowChildren(mFrames.FirstChild());
        }

        // 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.

        nsEmbellishData parentData;
        GetEmbellishDataFrom(GetParent(), parentData);
        // ensure that we are the embellished child, not just a sibling
        // (need to test coreFrame since <mfrac> resets other things)
        if (parentData.coreFrame != mEmbellishData.coreFrame) {
          // (we fetch values from the core since they may use units that depend
          // on style data, and style changes could have occurred in the core
          // since our last visit there)
          nsEmbellishData coreData;
          GetEmbellishDataFrom(mEmbellishData.coreFrame, coreData);

          mBoundingMetrics.width +=
              coreData.leadingSpace + coreData.trailingSpace;
          aDesiredStretchSize.Width() = mBoundingMetrics.width;
          aDesiredStretchSize.mBoundingMetrics.width = mBoundingMetrics.width;

          nscoord dx = StyleVisibility()->mDirection == StyleDirection::Rtl
                           ? coreData.trailingSpace
                           : coreData.leadingSpace;
          if (dx != 0) {
            mBoundingMetrics.leftBearing += dx;
            mBoundingMetrics.rightBearing += dx;
            aDesiredStretchSize.mBoundingMetrics.leftBearing += dx;
            aDesiredStretchSize.mBoundingMetrics.rightBearing += dx;

            nsIFrame* childFrame = mFrames.FirstChild();
            while (childFrame) {
              childFrame->SetPosition(childFrame->GetPosition() +
                                      nsPoint(dx, 0));
              childFrame = childFrame->GetNextSibling();
            }
          }
        }

        // Finished with these:
        ClearSavedChildMetrics();
        // Set our overflow area
        GatherAndStoreOverflow(&aDesiredStretchSize);
      }
    }
  }
  return NS_OK;
}

nsresult nsMathMLContainerFrame::FinalizeReflow(DrawTarget* aDrawTarget,
                                                ReflowOutput& aDesiredSize) {
  // During reflow, we use rect.x and rect.y as placeholders for the child's
  // ascent and descent in expectation of a stretch command. Hence we need to
  // ensure that a stretch command will actually be fired later on, after
  // exiting from our reflow. If the stretch is not fired, the rect.x, and
  // rect.y will remain with inappropriate data causing children to be
  // improperly positioned. This helper method checks to see if our parent will
  // fire a stretch command targeted at us. If not, we go ahead and fire an
  // involutive stretch on ourselves. This will clear all the rect.x and rect.y,
  // and return our desired size.

  // First, complete the post-reflow hook.
  // We use the information in our children rectangles to position them.
  // If placeOrigin==false, then Place() will not touch rect.x, and rect.y.
  // They will still be holding the ascent and descent for each child.

  // The first clause caters for any non-embellished container.
  // The second clause is for a container which won't fire stretch even though
  // it is embellished, e.g., as in <mfrac><mo>...</mo> ... </mfrac>, the test
  // is convoluted because it excludes the particular case of the core
  // <mo>...</mo> itself.
  // (<mo> needs to fire stretch on its MathMLChar in any case to initialize it)
  bool placeOrigin =
      !NS_MATHML_IS_EMBELLISH_OPERATOR(mEmbellishData.flags) ||
      (mEmbellishData.coreFrame != this && !mPresentationData.baseFrame &&
       mEmbellishData.direction == NS_STRETCH_DIRECTION_UNSUPPORTED);
  PlaceFlags flags;
  if (!placeOrigin) {
    flags += PlaceFlag::MeasureOnly;
  }
  nsresult rv = Place(aDrawTarget, flags, aDesiredSize);

  // Place() will call FinishReflowChild() when placeOrigin is true but if
  // it returns before reaching FinishReflowChild() due to errors we need
  // to fulfill the reflow protocol by calling DidReflow for the child frames
  // that still needs it here (or we may crash - bug 366012).
  // If placeOrigin is false we should reach Place() with
  // PlaceFlag::MeasureOnly unset through Stretch() eventually.
  if (NS_FAILED(rv)) {
    GatherAndStoreOverflow(&aDesiredSize);
    DidReflowChildren(PrincipalChildList().FirstChild());
    return rv;
  }

  bool parentWillFireStretch = false;
  if (!placeOrigin) {
    // This means the rect.x and rect.y of our children were not set!!
    // Don't go without checking to see if our parent will later fire a
    // Stretch() command targeted at us. The Stretch() will cause the rect.x and
    // rect.y to clear...
    nsIMathMLFrame* mathMLFrame = do_QueryFrame(GetParent());
    if (mathMLFrame) {
      nsEmbellishData embellishData;
      nsPresentationData presentationData;
      mathMLFrame->GetEmbellishData(embellishData);
      mathMLFrame->GetPresentationData(presentationData);
      if (NS_MATHML_WILL_STRETCH_ALL_CHILDREN_VERTICALLY(
              presentationData.flags) ||
          NS_MATHML_WILL_STRETCH_ALL_CHILDREN_HORIZONTALLY(
              presentationData.flags) ||
          (NS_MATHML_IS_EMBELLISH_OPERATOR(embellishData.flags) &&
           presentationData.baseFrame == this)) {
        parentWillFireStretch = true;
      }
    }
    if (!parentWillFireStretch) {
      // There is nobody who will fire the stretch for us, we do it ourselves!

      bool stretchAll =
          /* NS_MATHML_WILL_STRETCH_ALL_CHILDREN_VERTICALLY(mPresentationData.flags)
             || */
          NS_MATHML_WILL_STRETCH_ALL_CHILDREN_HORIZONTALLY(
              mPresentationData.flags);

      nsStretchDirection stretchDir;
      if (mEmbellishData.coreFrame ==
              this || /* case of a bare <mo>...</mo> itself */
          (mEmbellishData.direction == NS_STRETCH_DIRECTION_HORIZONTAL &&
           stretchAll) || /* or <mover><mo>...</mo>...</mover>, or friends */
          mEmbellishData.direction ==
              NS_STRETCH_DIRECTION_UNSUPPORTED) { /* Doesn't stretch */
        stretchDir = mEmbellishData.direction;
      } else {
        // Let the Stretch() call decide the direction.
        stretchDir = NS_STRETCH_DIRECTION_DEFAULT;
      }
      // Use our current size as computed earlier by Place()
      // The stretch call will detect if this is incorrect and recalculate the
      // size.
      nsBoundingMetrics defaultSize = aDesiredSize.mBoundingMetrics;

      Stretch(aDrawTarget, stretchDir, defaultSize, aDesiredSize);
#ifdef DEBUG
      {
        // The Place() call above didn't request FinishReflowChild(),
        // so let's check that we eventually did through Stretch().
        for (nsIFrame* childFrame : PrincipalChildList()) {
          NS_ASSERTION(!childFrame->HasAnyStateBits(NS_FRAME_IN_REFLOW),
                       "DidReflow() was never called");
        }
      }
#endif
    }
  }

  // Also return our bounding metrics
  aDesiredSize.mBoundingMetrics = mBoundingMetrics;

  // see if we should fix the spacing
  FixInterFrameSpacing(aDesiredSize);

  if (!parentWillFireStretch) {
    // Not expecting a stretch.
    // Finished with these:
    ClearSavedChildMetrics();
    // Set our overflow area.
    GatherAndStoreOverflow(&aDesiredSize);
  }

  return NS_OK;
}

/* /////////////
* nsIMathMLFrame - support methods for scripting elements (nested frames
* within msub, msup, msubsup, munder, mover, munderover, mmultiscripts,
* mfrac, mroot, mtable).
* =============================================================================
*/

// helper to let the update of presentation data pass through
// a subtree that may contain non-mathml container frames
/* static */
void nsMathMLContainerFrame::PropagatePresentationDataFor(
    nsIFrame* aFrame, uint32_t aFlagsValues, uint32_t aFlagsToUpdate) {
  if (!aFrame || !aFlagsToUpdate) {
    return;
  }
  nsIMathMLFrame* mathMLFrame = do_QueryFrame(aFrame);
  if (mathMLFrame) {
    // update
    mathMLFrame->UpdatePresentationData(aFlagsValues, aFlagsToUpdate);
    // propagate using the base method to make sure that the control
    // is passed on to MathML frames that may be overloading the method
    mathMLFrame->UpdatePresentationDataFromChildAt(0, -1, aFlagsValues,
                                                   aFlagsToUpdate);
  } else {
    // propagate down the subtrees
    for (nsIFrame* childFrame : aFrame->PrincipalChildList()) {
      PropagatePresentationDataFor(childFrame, aFlagsValues, aFlagsToUpdate);
    }
  }
}

/* static */
void nsMathMLContainerFrame::PropagatePresentationDataFromChildAt(
    nsIFrame* aParentFrame, int32_t aFirstChildIndex, int32_t aLastChildIndex,
    uint32_t aFlagsValues, uint32_t aFlagsToUpdate) {
  if (!aParentFrame || !aFlagsToUpdate) {
    return;
  }
  int32_t index = 0;
  for (nsIFrame* childFrame : aParentFrame->PrincipalChildList()) {
    if ((index >= aFirstChildIndex) &&
        ((aLastChildIndex <= 0) ||
         ((aLastChildIndex > 0) && (index <= aLastChildIndex)))) {
      PropagatePresentationDataFor(childFrame, aFlagsValues, aFlagsToUpdate);
    }
    index++;
  }
}

/* //////////////////
* Frame construction
* =============================================================================
*/

void nsMathMLContainerFrame::BuildDisplayList(nsDisplayListBuilder* aBuilder,
                                              const nsDisplayListSet& aLists) {
  BuildDisplayListForInline(aBuilder, aLists);
}

// Note that this method re-builds the automatic data in the children -- not
// in aParentFrame itself (except for those particular operations that the
// parent frame may do in its TransmitAutomaticData()).
/* static */
void nsMathMLContainerFrame::RebuildAutomaticDataForChildren(
    nsIFrame* aParentFrame) {
  // 1. As we descend the tree, make each child frame inherit data from
  // the parent
  // 2. As we ascend the tree, transmit any specific change that we want
  // down the subtrees
  for (nsIFrame* childFrame : aParentFrame->PrincipalChildList()) {
    nsIMathMLFrame* childMathMLFrame = do_QueryFrame(childFrame);
    if (childMathMLFrame) {
      childMathMLFrame->InheritAutomaticData(aParentFrame);
    }
    RebuildAutomaticDataForChildren(childFrame);
  }
  nsIMathMLFrame* mathMLFrame = do_QueryFrame(aParentFrame);
  if (mathMLFrame) {
    mathMLFrame->TransmitAutomaticData();
  }
}

/* static */
nsresult nsMathMLContainerFrame::ReLayoutChildren(nsIFrame* aParentFrame) {
  if (!aParentFrame) {
    return NS_OK;
  }

  // walk-up to the first frame that is a MathML frame, stop if we reach <math>
  nsIFrame* frame = aParentFrame;
  while (1) {
    nsIFrame* parent = frame->GetParent();
    if (!parent || !parent->GetContent()) {
      break;
    }

    // stop if it is a MathML frame
    nsIMathMLFrame* mathMLFrame = do_QueryFrame(frame);
    if (mathMLFrame) {
      break;
    }

    // stop if we reach the root <math> tag
    nsIContent* content = frame->GetContent();
    NS_ASSERTION(content, "dangling frame without a content node");
    if (!content) {
      break;
    }
    if (content->IsMathMLElement(nsGkAtoms::math)) {
      break;
    }

    frame = parent;
  }

  // re-sync the presentation data and embellishment data of our children
  RebuildAutomaticDataForChildren(frame);

  // Ask our parent frame to reflow us
  nsIFrame* parent = frame->GetParent();
  NS_ASSERTION(parent, "No parent to pass the reflow request up to");
  if (!parent) {
    return NS_OK;
  }

  frame->PresShell()->FrameNeedsReflow(
      frame, IntrinsicDirty::FrameAncestorsAndDescendants, NS_FRAME_IS_DIRTY);

  return NS_OK;
}

// There are precise rules governing children of a MathML frame,
// and properties such as the scriptlevel depends on those rules.
// Hence for things to work, callers must use Append/Insert/etc wisely.

nsresult nsMathMLContainerFrame::ChildListChanged(int32_t aModType) {
  // If this is an embellished frame we need to rebuild the
  // embellished hierarchy by walking-up to the parent of the
  // outermost embellished container.
  nsIFrame* frame = this;
  if (mEmbellishData.coreFrame) {
    nsIFrame* parent = GetParent();
    nsEmbellishData embellishData;
    for (; parent; frame = parent, parent = parent->GetParent()) {
      GetEmbellishDataFrom(parent, embellishData);
      if (embellishData.coreFrame != mEmbellishData.coreFrame) {
        break;
      }
    }
  }
  return ReLayoutChildren(frame);
}

void nsMathMLContainerFrame::AppendFrames(ChildListID aListID,
                                          nsFrameList&& aFrameList) {
  MOZ_ASSERT(aListID == FrameChildListID::Principal);
  mFrames.AppendFrames(this, std::move(aFrameList));
  ChildListChanged(dom::MutationEvent_Binding::ADDITION);
}

void nsMathMLContainerFrame::InsertFrames(
    ChildListID aListID, nsIFrame* aPrevFrame,
    const nsLineList::iterator* aPrevFrameLine, nsFrameList&& aFrameList) {
  MOZ_ASSERT(aListID == FrameChildListID::Principal);
  mFrames.InsertFrames(this, aPrevFrame, std::move(aFrameList));
  ChildListChanged(dom::MutationEvent_Binding::ADDITION);
}

void nsMathMLContainerFrame::RemoveFrame(DestroyContext& aContext,
                                         ChildListID aListID,
                                         nsIFrame* aOldFrame) {
  MOZ_ASSERT(aListID == FrameChildListID::Principal);
  mFrames.DestroyFrame(aContext, aOldFrame);
  ChildListChanged(dom::MutationEvent_Binding::REMOVAL);
}

void nsMathMLContainerFrame::GatherAndStoreOverflow(ReflowOutput* aMetrics) {
  mBlockStartAscent = aMetrics->BlockStartAscent();

  // nsIFrame::FinishAndStoreOverflow likes the overflow area to include the
  // frame rectangle.
  aMetrics->SetOverflowAreasToDesiredBounds();

  ComputeCustomOverflow(aMetrics->mOverflowAreas);

  // mBoundingMetrics does not necessarily include content of <mpadded>
  // elements whose mBoundingMetrics may not be representative of the true
  // bounds, and doesn't include the CSS2 outline rectangles of children, so
  // make such to include child overflow areas.
  UnionChildOverflow(aMetrics->mOverflowAreas);

  FinishAndStoreOverflow(aMetrics);
}

bool nsMathMLContainerFrame::ComputeCustomOverflow(
    OverflowAreas& aOverflowAreas) {
  // All non-child-frame content such as nsMathMLChars (and most child-frame
  // content) is included in mBoundingMetrics.
  nsRect boundingBox(
      mBoundingMetrics.leftBearing, mBlockStartAscent - mBoundingMetrics.ascent,
      mBoundingMetrics.rightBearing - mBoundingMetrics.leftBearing,
      mBoundingMetrics.ascent + mBoundingMetrics.descent);

  // REVIEW: Maybe this should contribute only to ink overflow
  // and not scrollable?
  aOverflowAreas.UnionAllWith(boundingBox);
  return nsContainerFrame::ComputeCustomOverflow(aOverflowAreas);
}

void nsMathMLContainerFrame::ReflowChild(nsIFrame* aChildFrame,
                                         nsPresContext* aPresContext,
                                         ReflowOutput& aDesiredSize,
                                         const ReflowInput& aReflowInput,
                                         nsReflowStatus& aStatus) {
  // Having foreign/hybrid children, e.g., from html markups, is not defined by
  // the MathML spec. But it can happen in practice, e.g., <html:img> allows us
  // to do some cool demos... or we may have a child that is an nsInlineFrame
  // from a generated content such as :before { content: open-quote } or
  // :after { content: close-quote }. Unfortunately, the other frames out-there
  // may expect their own invariants that are not met when we mix things.
  // Hence we do not claim their support, but we will nevertheless attempt to
  // keep them in the flow, if we can get their desired size. We observed that
  // most frames may be reflowed generically, but nsInlineFrames need extra
  // care.

#ifdef DEBUG
  nsInlineFrame* inlineFrame = do_QueryFrame(aChildFrame);
  NS_ASSERTION(!inlineFrame, "Inline frames should be wrapped in blocks");
#endif

  nsContainerFrame::ReflowChild(aChildFrame, aPresContext, aDesiredSize,
                                aReflowInput, 0, 0,
                                ReflowChildFlags::NoMoveFrame, aStatus);

  if (aDesiredSize.BlockStartAscent() == ReflowOutput::ASK_FOR_BASELINE) {
    // This will be suitable for inline frames, which are wrapped in a block.
    nscoord ascent;
    WritingMode wm = aDesiredSize.GetWritingMode();
    if (!nsLayoutUtils::GetLastLineBaseline(wm, aChildFrame, &ascent)) {
      // We don't expect any other block children so just place the frame on
      // the baseline instead of going through DidReflow() and
      // GetBaseline().  This is what nsIFrame::GetBaseline() will do anyway.
      aDesiredSize.SetBlockStartAscent(aDesiredSize.BSize(wm));
    } else {
      aDesiredSize.SetBlockStartAscent(ascent);
    }
  }
  if (IsForeignChild(aChildFrame)) {
    // use ComputeTightBounds API as aDesiredSize.mBoundingMetrics is not set.
    nsRect r = aChildFrame->ComputeTightBounds(
        aReflowInput.mRenderingContext->GetDrawTarget());
    aDesiredSize.mBoundingMetrics.leftBearing = r.x;
    aDesiredSize.mBoundingMetrics.rightBearing = r.XMost();
    aDesiredSize.mBoundingMetrics.ascent =
        aDesiredSize.BlockStartAscent() - r.y;
    aDesiredSize.mBoundingMetrics.descent =
        r.YMost() - aDesiredSize.BlockStartAscent();
    aDesiredSize.mBoundingMetrics.width = aDesiredSize.Width();
  }
}

void nsMathMLContainerFrame::Reflow(nsPresContext* aPresContext,
                                    ReflowOutput& aDesiredSize,
                                    const ReflowInput& aReflowInput,
                                    nsReflowStatus& aStatus) {
  if (IsHiddenByContentVisibilityOfInFlowParentForLayout()) {
    return;
  }

  MarkInReflow();
  MOZ_ASSERT(aStatus.IsEmpty(), "Caller should pass a fresh reflow status!");

  aDesiredSize.Width() = aDesiredSize.Height() = 0;
  aDesiredSize.SetBlockStartAscent(0);
  aDesiredSize.mBoundingMetrics = nsBoundingMetrics();

  /////////////
  // Reflow children
  // Asking each child to cache its bounding metrics

  nsReflowStatus childStatus;
  nsIFrame* childFrame = mFrames.FirstChild();
  while (childFrame) {
    ReflowOutput childDesiredSize(aReflowInput);
    WritingMode wm = childFrame->GetWritingMode();
    LogicalSize availSize = aReflowInput.ComputedSize(wm);
    availSize.BSize(wm) = NS_UNCONSTRAINEDSIZE;
    ReflowInput childReflowInput(aPresContext, aReflowInput, childFrame,
                                 availSize);
    ReflowChild(childFrame, aPresContext, childDesiredSize, childReflowInput,
                childStatus);
    // NS_ASSERTION(childStatus.IsComplete(), "bad status");
    SaveReflowAndBoundingMetricsFor(childFrame, childDesiredSize,
                                    childDesiredSize.mBoundingMetrics);
    childFrame = childFrame->GetNextSibling();
  }

  /////////////
  // If we are a container which is entitled to stretch its children, then we
  // ask our stretchy children to stretch themselves

  // The stretching of siblings of an embellished child is _deferred_ until
  // after finishing the stretching of the embellished child - bug 117652

  DrawTarget* drawTarget = aReflowInput.mRenderingContext->GetDrawTarget();

  if (!NS_MATHML_IS_EMBELLISH_OPERATOR(mEmbellishData.flags) &&
      (NS_MATHML_WILL_STRETCH_ALL_CHILDREN_VERTICALLY(
           mPresentationData.flags) ||
       NS_MATHML_WILL_STRETCH_ALL_CHILDREN_HORIZONTALLY(
           mPresentationData.flags))) {
    // get the stretchy direction
    nsStretchDirection stretchDir =
        NS_MATHML_WILL_STRETCH_ALL_CHILDREN_VERTICALLY(mPresentationData.flags)
            ? NS_STRETCH_DIRECTION_VERTICAL
            : NS_STRETCH_DIRECTION_HORIZONTAL;

    // what size should we use to stretch our stretchy children
    // We don't use STRETCH_CONSIDER_ACTUAL_SIZE -- because our size is not
    // known yet We don't use STRETCH_CONSIDER_EMBELLISHMENTS -- because we
    // don't want to include them in the caculations of the size of stretchy
    // elements
    nsBoundingMetrics containerSize;
    GetPreferredStretchSize(drawTarget, 0, stretchDir, containerSize);

    // fire the stretch on each child
    childFrame = mFrames.FirstChild();
    while (childFrame) {
      nsIMathMLFrame* mathMLFrame = do_QueryFrame(childFrame);
      if (mathMLFrame) {
        // retrieve the metrics that was stored at the previous pass
        ReflowOutput childDesiredSize(aReflowInput);
        GetReflowAndBoundingMetricsFor(childFrame, childDesiredSize,
                                       childDesiredSize.mBoundingMetrics);

        mathMLFrame->Stretch(drawTarget, stretchDir, containerSize,
                             childDesiredSize);
        // store the updated metrics
        SaveReflowAndBoundingMetricsFor(childFrame, childDesiredSize,
                                        childDesiredSize.mBoundingMetrics);
      }
      childFrame = childFrame->GetNextSibling();
    }
  }

  /////////////
  // Place children now by re-adjusting the origins to align the baselines
  FinalizeReflow(drawTarget, aDesiredSize);
}

static nscoord AddInterFrameSpacingToSize(ReflowOutput& aDesiredSize,
                                          nsMathMLContainerFrame* aFrame);

/* virtual */
void nsMathMLContainerFrame::MarkIntrinsicISizesDirty() {
  mIntrinsicISize = NS_INTRINSIC_ISIZE_UNKNOWN;
  nsContainerFrame::MarkIntrinsicISizesDirty();
}

void nsMathMLContainerFrame::UpdateIntrinsicISize(
    gfxContext* aRenderingContext) {
  if (mIntrinsicISize == NS_INTRINSIC_ISIZE_UNKNOWN) {
    ReflowOutput desiredSize(GetWritingMode());
    GetIntrinsicISizeMetrics(aRenderingContext, desiredSize);

    // Include the additional width added by FixInterFrameSpacing to ensure
    // consistent width calculations.
    AddInterFrameSpacingToSize(desiredSize, this);

    // ReflowOuput::mSize corresponds to the border box, but callers
    // expect padding/border are not included.
    mIntrinsicISize = desiredSize.ISize(GetWritingMode()) -
                      IntrinsicISizeOffsets().BorderPadding();
  }
}

nscoord nsMathMLContainerFrame::IntrinsicISize(const IntrinsicSizeInput& aInput,
                                               IntrinsicISizeType aType) {
  UpdateIntrinsicISize(aInput.mContext);
  return mIntrinsicISize;
}

/* virtual */
void nsMathMLContainerFrame::GetIntrinsicISizeMetrics(
    gfxContext* aRenderingContext, ReflowOutput& aDesiredSize) {
  // Get child widths
  nsIFrame* childFrame = mFrames.FirstChild();
  while (childFrame) {
    ReflowOutput childDesiredSize(GetWritingMode());  // ???

    nsMathMLContainerFrame* containerFrame = do_QueryFrame(childFrame);
    if (containerFrame) {
      containerFrame->GetIntrinsicISizeMetrics(aRenderingContext,
                                               childDesiredSize);
    } else {
      nscoord width = nsLayoutUtils::IntrinsicForContainer(
          aRenderingContext, childFrame, IntrinsicISizeType::PrefISize);

      childDesiredSize.Width() = width;
      childDesiredSize.mBoundingMetrics.width = width;
      childDesiredSize.mBoundingMetrics.leftBearing = 0;
      childDesiredSize.mBoundingMetrics.rightBearing = width;

      nscoord x, xMost;
      if (NS_SUCCEEDED(childFrame->GetPrefWidthTightBounds(aRenderingContext,
                                                           &x, &xMost))) {
        childDesiredSize.mBoundingMetrics.leftBearing = x;
        childDesiredSize.mBoundingMetrics.rightBearing = xMost;
      }
    }

    SaveReflowAndBoundingMetricsFor(childFrame, childDesiredSize,
                                    childDesiredSize.mBoundingMetrics);

    childFrame = childFrame->GetNextSibling();
  }

  // Measure
  PlaceFlags flags(PlaceFlag::IntrinsicSize, PlaceFlag::MeasureOnly);
  nsresult rv = Place(aRenderingContext->GetDrawTarget(), flags, aDesiredSize);
  if (NS_FAILED(rv)) {
    PlaceAsMrow(aRenderingContext->GetDrawTarget(), flags, aDesiredSize);
  }

  ClearSavedChildMetrics();
}

// see spacing table in Chapter 18, TeXBook (p.170)
// Our table isn't quite identical to TeX because operators have
// built-in values for lspace & rspace in the Operator Dictionary.
static int32_t
    kInterFrameSpacingTable[eMathMLFrameType_COUNT][eMathMLFrameType_COUNT] = {
        // in units of muspace.
        // upper half of the byte is set if the
        // spacing is not to be used for scriptlevel > 0

        /*           Ord  OpOrd OpInv OpUsr Inner Italic Upright */
        /*Ord    */ {0x00, 0x00, 0x00, 0x01, 0x01, 0x00, 0x00},
        /*OpOrd  */ {0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00},
        /*OpInv  */ {0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00},
        /*OpUsr  */ {0x01, 0x00, 0x00, 0x01, 0x01, 0x01, 0x01},
        /*Inner  */ {0x01, 0x00, 0x00, 0x01, 0x01, 0x01, 0x01},
        /*Italic */ {0x00, 0x00, 0x00, 0x01, 0x01, 0x00, 0x01},
        /*Upright*/ {0x00, 0x00, 0x00, 0x01, 0x01, 0x01, 0x00}};

#define GET_INTERSPACE(scriptlevel_, frametype1_, frametype2_, space_) \
  /* no space if there is a frame that we know nothing about */        \
  if (frametype1_ == eMathMLFrameType_UNKNOWN ||                       \
      frametype2_ == eMathMLFrameType_UNKNOWN)                         \
    space_ = 0;                                                        \
  else {                                                               \
    space_ = kInterFrameSpacingTable[frametype1_][frametype2_];        \
    space_ = (scriptlevel_ > 0 && (space_ & 0xF0))                     \
                 ? 0 /* spacing is disabled */                         \
                 : space_ & 0x0F;                                      \
  }

// This function computes the inter-space between two frames. However,
// since invisible operators need special treatment, the inter-space may
// be delayed when an invisible operator is encountered. In this case,
// the function will carry the inter-space forward until it is determined
// that it can be applied properly (i.e., until we encounter a visible
// frame where to decide whether to accept or reject the inter-space).
// aFromFrameType: remembers the frame when the carry-forward initiated.
// aCarrySpace: keeps track of the inter-space that is delayed.
// @returns: current inter-space (which is 0 when the true inter-space is
// delayed -- and thus has no effect since the frame is invisible anyway).
static nscoord GetInterFrameSpacing(int32_t aScriptLevel,
                                    eMathMLFrameType aFirstFrameType,
                                    eMathMLFrameType aSecondFrameType,
                                    eMathMLFrameType* aFromFrameType,  // IN/OUT
                                    int32_t* aCarrySpace)              // IN/OUT
{
  eMathMLFrameType firstType = aFirstFrameType;
  eMathMLFrameType secondType = aSecondFrameType;

  int32_t space;
  GET_INTERSPACE(aScriptLevel, firstType, secondType, space);

  // feedback control to avoid the inter-space to be added when not necessary
  if (secondType == eMathMLFrameType_OperatorInvisible) {
    // see if we should start to carry the space forward until we
    // encounter a visible frame
    if (*aFromFrameType == eMathMLFrameType_UNKNOWN) {
      *aFromFrameType = firstType;
      *aCarrySpace = space;
    }
    // keep carrying *aCarrySpace forward, while returning 0 for this stage
    space = 0;
  } else if (*aFromFrameType != eMathMLFrameType_UNKNOWN) {
    // no carry-forward anymore, get the real inter-space between
    // the two frames of interest

    firstType = *aFromFrameType;

    // But... the invisible operator that we encountered earlier could
    // be sitting between italic and upright identifiers, e.g.,
    //
    // 1. <mi>sin</mi> <mo>⁡</mo> <mi>x</mi>
    // 2. <mi>x</mi> <mo>&InvisibileTime;</mo> <mi>sin</mi>
    //
    // the trick to get the inter-space in either situation
    // is to promote "<mi>sin</mi><mo>⁡</mo>" and
    // "<mo>&InvisibileTime;</mo><mi>sin</mi>" to user-defined operators...
    if (firstType == eMathMLFrameType_UprightIdentifier) {
      firstType = eMathMLFrameType_OperatorUserDefined;
    } else if (secondType == eMathMLFrameType_UprightIdentifier) {
      secondType = eMathMLFrameType_OperatorUserDefined;
    }

    GET_INTERSPACE(aScriptLevel, firstType, secondType, space);

    // Now, we have two values: the computed space and the space that
    // has been carried forward until now. Which value do we pick?
    // If the second type is an operator (e.g., fence), it already has
    // built-in lspace & rspace, so we let them win. Otherwise we pick
    // the max between the two values that we have.
    if (secondType != eMathMLFrameType_OperatorOrdinary &&
        space < *aCarrySpace) {
      space = *aCarrySpace;
    }

    // reset everything now that the carry-forward is done
    *aFromFrameType = eMathMLFrameType_UNKNOWN;
    *aCarrySpace = 0;
  }

  return space;
}

static nscoord GetThinSpace(const nsStyleFont* aStyleFont) {
  return aStyleFont->mFont.size.ScaledBy(3.0f / 18.0f).ToAppUnits();
}

class nsMathMLContainerFrame::RowChildFrameIterator {
public:
  explicit RowChildFrameIterator(nsMathMLContainerFrame* aParentFrame,
                                 const PlaceFlags& aFlags)
      : mParentFrame(aParentFrame),
        mReflowOutput(aParentFrame->GetWritingMode()),
        mX(0),
        mFlags(aFlags),
        mChildFrameType(eMathMLFrameType_UNKNOWN),
        mCarrySpace(0),
        mFromFrameType(eMathMLFrameType_UNKNOWN),
        mRTL(aParentFrame->StyleVisibility()->mDirection ==
             StyleDirection::Rtl) {
    if (!mRTL) {
      mChildFrame = aParentFrame->mFrames.FirstChild();
    } else {
      mChildFrame = aParentFrame->mFrames.LastChild();
    }

    if (!mChildFrame) {
      return;
    }

    InitMetricsForChild();
  }

  RowChildFrameIterator& operator++() {
    // add child size + italic correction
    mX += mReflowOutput.mBoundingMetrics.width + mItalicCorrection;
    mX += mMargin.LeftRight();

    if (!mRTL) {
      mChildFrame = mChildFrame->GetNextSibling();
    } else {
      mChildFrame = mChildFrame->GetPrevSibling();
    }

    if (!mChildFrame) {
      return *this;
    }

    eMathMLFrameType prevFrameType = mChildFrameType;
    InitMetricsForChild();

    // add inter frame spacing
    const nsStyleFont* font = mParentFrame->StyleFont();
    nscoord space =
        GetInterFrameSpacing(font->mMathDepth, prevFrameType, mChildFrameType,
                             &mFromFrameType, &mCarrySpace);
    mX += space * GetThinSpace(font);
    return *this;
  }

  nsIFrame* Frame() const { return mChildFrame; }
  nscoord X() const { return mX; }
  const ReflowOutput& GetReflowOutput() const { return mReflowOutput; }
  nscoord Ascent() const { return mReflowOutput.BlockStartAscent(); }
  nscoord Descent() const {
    return mReflowOutput.Height() - mReflowOutput.BlockStartAscent();
  }
  const nsMargin& Margin() const { return mMargin; }
  const nsBoundingMetrics& BoundingMetrics() const {
    return mReflowOutput.mBoundingMetrics;
  }

private:
  const nsMathMLContainerFrame* mParentFrame;
  nsIFrame* mChildFrame;
  ReflowOutput mReflowOutput;
  nscoord mX;
  const PlaceFlags mFlags;
  nsMargin mMargin;

  nscoord mItalicCorrection;
  eMathMLFrameType mChildFrameType;
  int32_t mCarrySpace;
  eMathMLFrameType mFromFrameType;

  bool mRTL;

  void InitMetricsForChild() {
    GetReflowAndBoundingMetricsFor(mChildFrame, mReflowOutput,
                                   mReflowOutput.mBoundingMetrics,
                                   &mChildFrameType);
    mMargin = GetMarginForPlace(mFlags, mChildFrame);
    nscoord leftCorrection, rightCorrection;
    GetItalicCorrection(mReflowOutput.mBoundingMetrics, leftCorrection,
                        rightCorrection);
    if (!mChildFrame->GetPrevSibling() &&
        mParentFrame->GetContent()->IsMathMLElement(nsGkAtoms::msqrt_)) {
      // Remove leading correction in <msqrt> because the sqrt glyph itself is
      // there first.
      if (!mRTL) {
        leftCorrection = 0;
      } else {
        rightCorrection = 0;
      }
    }
    // add left correction -- this fixes the problem of the italic 'f'
    // e.g., <mo>q</mo> <mi>f</mi> <mo>I</mo>
    mX += leftCorrection;
    mItalicCorrection = rightCorrection;
  }
};

/* virtual */
nsresult nsMathMLContainerFrame::Place(DrawTarget* aDrawTarget,
                                       const PlaceFlags& aFlags,
                                       ReflowOutput& aDesiredSize) {
  // This is needed in case this frame is empty (i.e., no child frames)
  mBoundingMetrics = nsBoundingMetrics();

  RowChildFrameIterator child(this, aFlags);
  nscoord ascent = 0, descent = 0;
  while (child.Frame()) {
    nscoord topMargin = child.Margin().top;
    nscoord bottomMargin = child.Margin().bottom;
    ascent = std::max(ascent, child.Ascent() + topMargin);
    descent = std::max(descent, child.Descent() + bottomMargin);

    // add the child size
    mBoundingMetrics.width = child.X();
    nsBoundingMetrics childBm = child.BoundingMetrics();
    childBm.ascent += topMargin;
    childBm.descent += bottomMargin;
    childBm.rightBearing += child.Margin().LeftRight();
    childBm.width += child.Margin().LeftRight();
    mBoundingMetrics += childBm;

    ++child;
  }

  // Add the italic correction at the end (including the last child).
  // This gives a nice gap between math and non-math frames, and still
  // gives the same math inter-spacing in case this frame connects to
  // another math frame
  mBoundingMetrics.width = child.X();

  aDesiredSize.Width() = std::max(0, mBoundingMetrics.width);
  aDesiredSize.Height() = ascent + descent;
  aDesiredSize.SetBlockStartAscent(ascent);
  aDesiredSize.mBoundingMetrics = mBoundingMetrics;

  // Apply inline/block sizes to math content box.
  auto sizes = GetWidthAndHeightForPlaceAdjustment(aFlags);
  nscoord shiftX = ApplyAdjustmentForWidthAndHeight(aFlags, sizes, aDesiredSize,
                                                    mBoundingMetrics);

  // Add padding+border.
  auto borderPadding = GetBorderPaddingForPlace(aFlags);
  InflateReflowAndBoundingMetrics(borderPadding, aDesiredSize,
                                  mBoundingMetrics);
  shiftX += borderPadding.left;

  mReference.x = 0;
  mReference.y = aDesiredSize.BlockStartAscent();

  //////////////////
  // Place Children
  if (!aFlags.contains(PlaceFlag::MeasureOnly)) {
    PositionRowChildFrames(shiftX, aDesiredSize.BlockStartAscent());
  }

  return NS_OK;
}

nsresult nsMathMLContainerFrame::PlaceAsMrow(DrawTarget* aDrawTarget,
                                             const PlaceFlags& aFlags,
                                             ReflowOutput& aDesiredSize) {
  return nsMathMLContainerFrame::Place(aDrawTarget, aFlags, aDesiredSize);
}

void nsMathMLContainerFrame::PositionRowChildFrames(nscoord aOffsetX,
                                                    nscoord aBaseline) {
  PlaceFlags flags;
  RowChildFrameIterator child(this, flags);
  while (child.Frame()) {
    nscoord dx = aOffsetX + child.X() + child.Margin().left;
    nscoord dy = aBaseline - child.Ascent();
    FinishReflowChild(child.Frame(), PresContext(), child.GetReflowOutput(),
                      nullptr, dx, dy, ReflowChildFlags::Default);
    ++child;
  }
}

// helpers to fix the inter-spacing when <math> is the only parent
// e.g., it fixes <math> <mi>f</mi> <mo>q</mo> <mi>f</mi> <mo>I</mo> </math>

static nscoord GetInterFrameSpacingFor(int32_t aScriptLevel,
                                       nsIFrame* aParentFrame,
                                       nsIFrame* aChildFrame) {
  nsIFrame* childFrame = aParentFrame->PrincipalChildList().FirstChild();
  if (!childFrame || aChildFrame == childFrame) {
    return 0;
  }

  int32_t carrySpace = 0;
  eMathMLFrameType fromFrameType = eMathMLFrameType_UNKNOWN;
  eMathMLFrameType prevFrameType = eMathMLFrameType_UNKNOWN;
  eMathMLFrameType childFrameType =
      nsMathMLFrame::GetMathMLFrameTypeFor(childFrame);
  childFrame = childFrame->GetNextSibling();
  while (childFrame) {
    prevFrameType = childFrameType;
    childFrameType = nsMathMLFrame::GetMathMLFrameTypeFor(childFrame);
    nscoord space =
        GetInterFrameSpacing(aScriptLevel, prevFrameType, childFrameType,
                             &fromFrameType, &carrySpace);
    if (aChildFrame == childFrame) {
      // get thinspace
      ComputedStyle* parentContext = aParentFrame->Style();
      nscoord thinSpace = GetThinSpace(parentContext->StyleFont());
      // we are done
      return space * thinSpace;
    }
    childFrame = childFrame->GetNextSibling();
  }

  MOZ_ASSERT_UNREACHABLE("child not in the childlist of its parent");
  return 0;
}

static nscoord AddInterFrameSpacingToSize(ReflowOutput& aDesiredSize,
                                          nsMathMLContainerFrame* aFrame) {
  nscoord gap = 0;
  nsIFrame* parent = aFrame->GetParent();
  nsIContent* parentContent = parent->GetContent();
  if (MOZ_UNLIKELY(!parentContent)) {
    return 0;
  }
  if (parentContent->IsAnyOfMathMLElements(nsGkAtoms::math, nsGkAtoms::mtd_)) {
    gap = GetInterFrameSpacingFor(aFrame->StyleFont()->mMathDepth, parent,
                                  aFrame);
    // add our own italic correction
    nscoord leftCorrection = 0, italicCorrection = 0;
    nsMathMLContainerFrame::GetItalicCorrection(
        aDesiredSize.mBoundingMetrics, leftCorrection, italicCorrection);
    gap += leftCorrection;
    if (gap) {
      aDesiredSize.mBoundingMetrics.leftBearing += gap;
      aDesiredSize.mBoundingMetrics.rightBearing += gap;
      aDesiredSize.mBoundingMetrics.width += gap;
      aDesiredSize.Width() += gap;
    }
    aDesiredSize.mBoundingMetrics.width += italicCorrection;
    aDesiredSize.Width() += italicCorrection;
  }
  return gap;
}

nscoord nsMathMLContainerFrame::FixInterFrameSpacing(
    ReflowOutput& aDesiredSize) {
  nscoord gap = 0;
  gap = AddInterFrameSpacingToSize(aDesiredSize, this);
  if (gap) {
    // Shift our children to account for the correction
    nsIFrame* childFrame = mFrames.FirstChild();
    while (childFrame) {
      childFrame->SetPosition(childFrame->GetPosition() + nsPoint(gap, 0));
      childFrame = childFrame->GetNextSibling();
    }
  }
  return gap;
}

/* static */
void nsMathMLContainerFrame::DidReflowChildren(nsIFrame* aFirst) {
  for (nsIFrame* frame = aFirst; frame; frame = frame->GetNextSibling()) {
    if (!frame->HasAnyStateBits(NS_FRAME_IN_REFLOW)) {
      continue;
    }
    if (nsIFrame* grandchild = frame->PrincipalChildList().FirstChild()) {
      // Finish off principal descendants, too
      DidReflowChildren(grandchild);
    }
    frame->DidReflow(frame->PresContext(), nullptr);
  }
}

// helper used by mstyle, mphantom, mpadded and mrow in their implementations
// of TransmitAutomaticData().
nsresult nsMathMLContainerFrame::TransmitAutomaticDataForMrowLikeElement() {
  //
  // One loop to check both conditions below:
  //
  // 1) whether all the children of the mrow-like element are space-like.
  //
  //   The REC defines the following elements to be "space-like":
  //   * an mstyle, mphantom, or mpadded element, all of whose direct
  //     sub-expressions are space-like;
  //   * an mrow all of whose direct sub-expressions are space-like.
  //
  // 2) whether all but one child of the mrow-like element are space-like and
  //    this non-space-like child is an embellished operator.
  //
  //   The REC defines the following elements to be embellished operators:
  //   * one of the elements mstyle, mphantom, or mpadded, such that an mrow
  //     containing the same arguments would be an embellished operator;
  //   * an mrow whose arguments consist (in any order) of one embellished
  //     operator and zero or more space-like elements.
  //
  nsIFrame *childFrame, *baseFrame;
  bool embellishedOpFound = false;
  nsEmbellishData embellishData;

  for (childFrame = PrincipalChildList().FirstChild(); childFrame;
       childFrame = childFrame->GetNextSibling()) {
    nsIMathMLFrame* mathMLFrame = do_QueryFrame(childFrame);
    if (!mathMLFrame) {
      break;
    }
    if (!mathMLFrame->IsSpaceLike()) {
      if (embellishedOpFound) {
        break;
      }
      baseFrame = childFrame;
      GetEmbellishDataFrom(baseFrame, embellishData);
      if (!NS_MATHML_IS_EMBELLISH_OPERATOR(embellishData.flags)) {
        break;
      }
      embellishedOpFound = true;
    }
  }

  if (!childFrame) {
    // we successfully went to the end of the loop. This means that one of
    // condition 1) or 2) holds.
    if (!embellishedOpFound) {
      // the mrow-like element is space-like.
      mPresentationData.flags |= NS_MATHML_SPACE_LIKE;
    } else {
      // the mrow-like element is an embellished operator.
      // let the state of the embellished operator found bubble to us.
      mPresentationData.baseFrame = baseFrame;
      mEmbellishData = embellishData;
    }
  }

  if (childFrame || !embellishedOpFound) {
    // The element is not embellished operator
    mPresentationData.baseFrame = nullptr;
    mEmbellishData.flags = 0;
    mEmbellishData.coreFrame = nullptr;
    mEmbellishData.direction = NS_STRETCH_DIRECTION_UNSUPPORTED;
    mEmbellishData.leadingSpace = 0;
    mEmbellishData.trailingSpace = 0;
  }

  if (childFrame || embellishedOpFound) {
    // The element is not space-like
    mPresentationData.flags &= ~NS_MATHML_SPACE_LIKE;
  }

  return NS_OK;
}

/*static*/
void nsMathMLContainerFrame::PropagateFrameFlagFor(nsIFrame* aFrame,
                                                   nsFrameState aFlags) {
  if (!aFrame || !aFlags) {
    return;
  }

  aFrame->AddStateBits(aFlags);
  for (nsIFrame* childFrame : aFrame->PrincipalChildList()) {
    PropagateFrameFlagFor(childFrame, aFlags);
  }
}

nsresult nsMathMLContainerFrame::ReportErrorToConsole(
    const char* errorMsgId, const nsTArray<nsString>& aParams) {
  return nsContentUtils::ReportToConsole(
      nsIScriptError::errorFlag, "Layout: MathML"_ns, mContent->OwnerDoc(),
      nsContentUtils::eMATHML_PROPERTIES, errorMsgId, aParams);
}

nsresult nsMathMLContainerFrame::ReportParseError(const char16_t* aAttribute,
                                                  const char16_t* aValue) {
  AutoTArray<nsString, 3> argv;
  argv.AppendElement(aValue);
  argv.AppendElement(aAttribute);
  argv.AppendElement(nsDependentAtomString(mContent->NodeInfo()->NameAtom()));
  return ReportErrorToConsole("AttributeParsingError", argv);
}

nsresult nsMathMLContainerFrame::ReportChildCountError() {
  AutoTArray<nsString, 1> arg = {
      nsDependentAtomString(mContent->NodeInfo()->NameAtom())};
  return ReportErrorToConsole("ChildCountIncorrect", arg);
}

nsresult nsMathMLContainerFrame::ReportInvalidChildError(nsAtom* aChildTag) {
  AutoTArray<nsString, 2> argv = {
      nsDependentAtomString(aChildTag),
      nsDependentAtomString(mContent->NodeInfo()->NameAtom())};
  return ReportErrorToConsole("InvalidChild", argv);
}

//==========================

nsContainerFrame* NS_NewMathMLmathBlockFrame(PresShell* aPresShell,
                                             ComputedStyle* aStyle) {
  auto newFrame = new (aPresShell)
      nsMathMLmathBlockFrame(aStyle, aPresShell->GetPresContext());
  return newFrame;
}

NS_IMPL_FRAMEARENA_HELPERS(nsMathMLmathBlockFrame)

NS_QUERYFRAME_HEAD(nsMathMLmathBlockFrame)
  NS_QUERYFRAME_ENTRY(nsMathMLmathBlockFrame)
NS_QUERYFRAME_TAIL_INHERITING(nsBlockFrame)

nsContainerFrame* NS_NewMathMLmathInlineFrame(PresShell* aPresShell,
                                              ComputedStyle* aStyle) {
  return new (aPresShell)
      nsMathMLmathInlineFrame(aStyle, aPresShell->GetPresContext());
}

NS_IMPL_FRAMEARENA_HELPERS(nsMathMLmathInlineFrame)

NS_QUERYFRAME_HEAD(nsMathMLmathInlineFrame)
  NS_QUERYFRAME_ENTRY(nsIMathMLFrame)
NS_QUERYFRAME_TAIL_INHERITING(nsInlineFrame)

quality93%

¤ Dauer der Verarbeitung: 0.30 Sekunden (vorverarbeitet) ¤

Wurzel

Suchen

Beweissystem der NASA

Beweissystem Isabelle

NIST Cobol Testsuite

Cephes Mathematical Library

Wiener Entwicklungsmethode

Haftungshinweis

Die Informationen auf dieser Webseite wurden nach bestem Wissen sorgfältig zusammengestellt. Es wird jedoch weder Vollständigkeit, noch Richtigkeit, noch Qualität der bereit gestellten Informationen zugesichert.

Bemerkung:

Die farbliche Syntaxdarstellung ist noch experimentell.