void
nsMathMLmpaddedFrame::UpdateValue(int32_t                  aSign,
                                  int32_t                  aPseudoUnit,
                                  const nsCSSValue&        aCSSValue,
                                  const ReflowOutput& aDesiredSize,
                                  nscoord&                 aValueToUpdate,
                                  float                aFontSizeInflation) const
{
  nsCSSUnit unit = aCSSValue.GetUnit();
  if (NS_MATHML_SIGN_INVALID != aSign && eCSSUnit_Null != unit) {
    nscoord scaler = 0, amount = 0;

    if (eCSSUnit_Percent == unit || eCSSUnit_Number == unit) {
      switch(aPseudoUnit) {
        case NS_MATHML_PSEUDO_UNIT_WIDTH:
             scaler = aDesiredSize.Width();
             break;

        case NS_MATHML_PSEUDO_UNIT_HEIGHT:
             scaler = aDesiredSize.BlockStartAscent();
             break;

        case NS_MATHML_PSEUDO_UNIT_DEPTH:
             scaler = aDesiredSize.Height() - aDesiredSize.BlockStartAscent();
             break;

        default:
          // if we ever reach here, it would mean something is wrong 
          // somewhere with the setup and/or the caller
          NS_ERROR("Unexpected Pseudo Unit");
          return;
      }
    }

    if (eCSSUnit_Number == unit)
      amount = NSToCoordRound(float(scaler) * aCSSValue.GetFloatValue());
    else if (eCSSUnit_Percent == unit)
      amount = NSToCoordRound(float(scaler) * aCSSValue.GetPercentValue());
    else
      amount = CalcLength(PresContext(), mStyleContext, aCSSValue,
                          aFontSizeInflation);

    if (NS_MATHML_SIGN_PLUS == aSign)
      aValueToUpdate += amount;
    else if (NS_MATHML_SIGN_MINUS == aSign)
      aValueToUpdate -= amount;
    else
      aValueToUpdate  = amount;
  }
}
void
nsSimplePageSequenceFrame::SetDesiredSize(ReflowOutput& aDesiredSize,
                                          const ReflowInput& aReflowInput,
                                          nscoord aWidth,
                                          nscoord aHeight)
{
    // Aim to fill the whole size of the document, not only so we
    // can act as a background in print preview but also handle overflow
    // in child page frames correctly.
    // Use availableWidth so we don't cause a needless horizontal scrollbar.
    aDesiredSize.Width() = std::max(aReflowInput.AvailableWidth(),
                                nscoord(aWidth * PresContext()->GetPrintPreviewScale()));
    aDesiredSize.Height() = std::max(aReflowInput.ComputedHeight(),
                                 nscoord(aHeight * PresContext()->GetPrintPreviewScale()));
}
Exemplo n.º 3
0
void
nsVideoFrame::Reflow(nsPresContext*           aPresContext,
                     ReflowOutput&     aMetrics,
                     const ReflowInput& aReflowInput,
                     nsReflowStatus&          aStatus)
{
  MarkInReflow();
  DO_GLOBAL_REFLOW_COUNT("nsVideoFrame");
  DISPLAY_REFLOW(aPresContext, this, aReflowInput, aMetrics, aStatus);
  NS_FRAME_TRACE(NS_FRAME_TRACE_CALLS,
                  ("enter nsVideoFrame::Reflow: availSize=%d,%d",
                  aReflowInput.AvailableWidth(), aReflowInput.AvailableHeight()));

  NS_PRECONDITION(mState & NS_FRAME_IN_REFLOW, "frame is not in reflow");

  aStatus = NS_FRAME_COMPLETE;

  aMetrics.Width() = aReflowInput.ComputedWidth();
  aMetrics.Height() = aReflowInput.ComputedHeight();

  // stash this away so we can compute our inner area later
  mBorderPadding   = aReflowInput.ComputedPhysicalBorderPadding();

  aMetrics.Width() += mBorderPadding.left + mBorderPadding.right;
  aMetrics.Height() += mBorderPadding.top + mBorderPadding.bottom;

  // Reflow the child frames. We may have up to two, an image frame
  // which is the poster, and a box frame, which is the video controls.
  for (nsIFrame* child : mFrames) {
    if (child->GetContent() == mPosterImage) {
      // Reflow the poster frame.
      nsImageFrame* imageFrame = static_cast<nsImageFrame*>(child);
      ReflowOutput kidDesiredSize(aReflowInput);
      WritingMode wm = imageFrame->GetWritingMode();
      LogicalSize availableSize = aReflowInput.AvailableSize(wm);
      LogicalSize cbSize = aMetrics.Size(aMetrics.GetWritingMode()).
                             ConvertTo(wm, aMetrics.GetWritingMode());
      ReflowInput kidReflowInput(aPresContext,
                                       aReflowInput,
                                       imageFrame,
                                       availableSize,
                                       &cbSize);

      nsRect posterRenderRect;
      if (ShouldDisplayPoster()) {
        posterRenderRect =
          nsRect(nsPoint(mBorderPadding.left, mBorderPadding.top),
                 nsSize(aReflowInput.ComputedWidth(),
                        aReflowInput.ComputedHeight()));
      }
      kidReflowInput.SetComputedWidth(posterRenderRect.width);
      kidReflowInput.SetComputedHeight(posterRenderRect.height);
      ReflowChild(imageFrame, aPresContext, kidDesiredSize, kidReflowInput,
                  posterRenderRect.x, posterRenderRect.y, 0, aStatus);
      FinishReflowChild(imageFrame, aPresContext,
                        kidDesiredSize, &kidReflowInput,
                        posterRenderRect.x, posterRenderRect.y, 0);
    } else if (child->GetContent() == mVideoControls) {
      // Reflow the video controls frame.
      nsBoxLayoutState boxState(PresContext(), aReflowInput.mRenderingContext);
      nsSize size = child->GetSize();
      nsBoxFrame::LayoutChildAt(boxState,
                                child,
                                nsRect(mBorderPadding.left,
                                       mBorderPadding.top,
                                       aReflowInput.ComputedWidth(),
                                       aReflowInput.ComputedHeight()));
      if (child->GetSize() != size) {
        RefPtr<Runnable> event = new DispatchResizeToControls(child->GetContent());
        nsContentUtils::AddScriptRunner(event);
      }
    } else if (child->GetContent() == mCaptionDiv) {
      // Reflow to caption div
      ReflowOutput kidDesiredSize(aReflowInput);
      WritingMode wm = child->GetWritingMode();
      LogicalSize availableSize = aReflowInput.AvailableSize(wm);
      LogicalSize cbSize = aMetrics.Size(aMetrics.GetWritingMode()).
                             ConvertTo(wm, aMetrics.GetWritingMode());
      ReflowInput kidReflowInput(aPresContext,
                                       aReflowInput,
                                       child,
                                       availableSize,
                                       &cbSize);
      nsSize size(aReflowInput.ComputedWidth(), aReflowInput.ComputedHeight());
      size.width -= kidReflowInput.ComputedPhysicalBorderPadding().LeftRight();
      size.height -= kidReflowInput.ComputedPhysicalBorderPadding().TopBottom();

      kidReflowInput.SetComputedWidth(std::max(size.width, 0));
      kidReflowInput.SetComputedHeight(std::max(size.height, 0));

      ReflowChild(child, aPresContext, kidDesiredSize, kidReflowInput,
                  mBorderPadding.left, mBorderPadding.top, 0, aStatus);
      FinishReflowChild(child, aPresContext,
                        kidDesiredSize, &kidReflowInput,
                        mBorderPadding.left, mBorderPadding.top, 0);
    }
  }
  aMetrics.SetOverflowAreasToDesiredBounds();

  FinishAndStoreOverflow(&aMetrics);

  NS_FRAME_TRACE(NS_FRAME_TRACE_CALLS,
                  ("exit nsVideoFrame::Reflow: size=%d,%d",
                  aMetrics.Width(), aMetrics.Height()));
  NS_FRAME_SET_TRUNCATION(aStatus, aReflowInput, aMetrics);
}
Exemplo n.º 4
0
void
nsInlineFrame::ReflowFrames(nsPresContext* aPresContext,
                            const ReflowInput& aReflowInput,
                            InlineReflowInput& irs,
                            ReflowOutput& aMetrics,
                            nsReflowStatus& aStatus)
{
  MOZ_ASSERT(aStatus.IsEmpty(), "Caller should pass a fresh reflow status!");

  nsLineLayout* lineLayout = aReflowInput.mLineLayout;
  bool inFirstLine = aReflowInput.mLineLayout->GetInFirstLine();
  RestyleManager* restyleManager = aPresContext->RestyleManager();
  WritingMode frameWM = aReflowInput.GetWritingMode();
  WritingMode lineWM = aReflowInput.mLineLayout->mRootSpan->mWritingMode;
  LogicalMargin framePadding = aReflowInput.ComputedLogicalBorderPadding();
  nscoord startEdge = 0;
  const bool boxDecorationBreakClone =
    MOZ_UNLIKELY(StyleBorder()->mBoxDecorationBreak ==
                   StyleBoxDecorationBreak::Clone);
  // Don't offset by our start borderpadding if we have a prev continuation or
  // if we're in a part of an {ib} split other than the first one. For
  // box-decoration-break:clone we always offset our start since all
  // continuations have border/padding.
  if ((!GetPrevContinuation() && !FrameIsNonFirstInIBSplit()) ||
      boxDecorationBreakClone) {
    startEdge = framePadding.IStart(frameWM);
  }
  nscoord availableISize = aReflowInput.AvailableISize();
  NS_ASSERTION(availableISize != NS_UNCONSTRAINEDSIZE,
               "should no longer use available widths");
  // Subtract off inline axis border+padding from availableISize
  availableISize -= startEdge;
  availableISize -= framePadding.IEnd(frameWM);
  lineLayout->BeginSpan(this, &aReflowInput, startEdge,
                        startEdge + availableISize, &mBaseline);

  // First reflow our principal children.
  nsIFrame* frame = mFrames.FirstChild();
  bool done = false;
  while (frame) {
    // Check if we should lazily set the child frame's parent pointer.
    if (irs.mSetParentPointer) {
      nsIFrame* child = frame;
      do {
        child->SetParent(this);
        if (inFirstLine) {
          restyleManager->ReparentStyleContext(child);
          nsLayoutUtils::MarkDescendantsDirty(child);
        }
        // We also need to do the same for |frame|'s next-in-flows that are in
        // the sibling list. Otherwise, if we reflow |frame| and it's complete
        // we'll crash when trying to delete its next-in-flow.
        // This scenario doesn't happen often, but it can happen.
        nsIFrame* nextSibling = child->GetNextSibling();
        child = child->GetNextInFlow();
        if (MOZ_UNLIKELY(child)) {
          while (child != nextSibling && nextSibling) {
            nextSibling = nextSibling->GetNextSibling();
          }
          if (!nextSibling) {
            child = nullptr;
          }
        }
        MOZ_ASSERT(!child || mFrames.ContainsFrame(child));
      } while (child);

      // Fix the parent pointer for ::first-letter child frame next-in-flows,
      // so nsFirstLetterFrame::Reflow can destroy them safely (bug 401042).
      nsIFrame* realFrame = nsPlaceholderFrame::GetRealFrameFor(frame);
      if (realFrame->IsLetterFrame()) {
        nsIFrame* child = realFrame->PrincipalChildList().FirstChild();
        if (child) {
          NS_ASSERTION(child->IsTextFrame(), "unexpected frame type");
          nsIFrame* nextInFlow = child->GetNextInFlow();
          for ( ; nextInFlow; nextInFlow = nextInFlow->GetNextInFlow()) {
            NS_ASSERTION(nextInFlow->IsTextFrame(), "unexpected frame type");
            if (mFrames.ContainsFrame(nextInFlow)) {
              nextInFlow->SetParent(this);
              if (inFirstLine) {
                restyleManager->ReparentStyleContext(nextInFlow);
                nsLayoutUtils::MarkDescendantsDirty(nextInFlow);
              }
            }
            else {
#ifdef DEBUG
              // Once we find a next-in-flow that isn't ours none of the
              // remaining next-in-flows should be either.
              for ( ; nextInFlow; nextInFlow = nextInFlow->GetNextInFlow()) {
                NS_ASSERTION(!mFrames.ContainsFrame(nextInFlow),
                             "unexpected letter frame flow");
              }
#endif
              break;
            }
          }
        }
      }
    }
    MOZ_ASSERT(frame->GetParent() == this);

    if (!done) {
      bool reflowingFirstLetter = lineLayout->GetFirstLetterStyleOK();
      ReflowInlineFrame(aPresContext, aReflowInput, irs, frame, aStatus);
      done = aStatus.IsInlineBreak() ||
             (!reflowingFirstLetter && aStatus.IsIncomplete());
      if (done) {
        if (!irs.mSetParentPointer) {
          break;
        }
        // Keep reparenting the remaining siblings, but don't reflow them.
        nsFrameList* pushedFrames = GetOverflowFrames();
        if (pushedFrames && pushedFrames->FirstChild() == frame) {
          // Don't bother if |frame| was pushed to our overflow list.
          break;
        }
      } else {
        irs.mPrevFrame = frame;
      }
    }
    frame = frame->GetNextSibling();
  }

  // Attempt to pull frames from our next-in-flow until we can't
  if (!done && GetNextInFlow()) {
    while (true) {
      bool reflowingFirstLetter = lineLayout->GetFirstLetterStyleOK();
      bool isComplete;
      if (!frame) { // Could be non-null if we pulled a first-letter frame and
                    // it created a continuation, since we don't push those.
        frame = PullOneFrame(aPresContext, irs, &isComplete);
      }
#ifdef NOISY_PUSHING
      printf("%p pulled up %p\n", this, frame);
#endif
      if (nullptr == frame) {
        if (!isComplete) {
          aStatus.Reset();
          aStatus.SetIncomplete();
        }
        break;
      }
      ReflowInlineFrame(aPresContext, aReflowInput, irs, frame, aStatus);
      if (aStatus.IsInlineBreak() ||
          (!reflowingFirstLetter && aStatus.IsIncomplete())) {
        break;
      }
      irs.mPrevFrame = frame;
      frame = frame->GetNextSibling();
    }
  }

  NS_ASSERTION(!aStatus.IsComplete() || !GetOverflowFrames(),
               "We can't be complete AND have overflow frames!");

  // If after reflowing our children they take up no area then make
  // sure that we don't either.
  //
  // Note: CSS demands that empty inline elements still affect the
  // line-height calculations. However, continuations of an inline
  // that are empty we force to empty so that things like collapsed
  // whitespace in an inline element don't affect the line-height.
  aMetrics.ISize(lineWM) = lineLayout->EndSpan(this);

  // Compute final width.

  // XXX Note that that the padding start and end are in the frame's
  //     writing mode, but the metrics' inline-size is in the line's
  //     writing mode. This makes sense if the line and frame are both
  //     vertical or both horizontal, but what should happen with
  //     orthogonal inlines?

  // Make sure to not include our start border and padding if we have a prev
  // continuation or if we're in a part of an {ib} split other than the first
  // one.  For box-decoration-break:clone we always include our start border
  // and padding since all continuations have them.
  if ((!GetPrevContinuation() && !FrameIsNonFirstInIBSplit()) ||
      boxDecorationBreakClone) {
    aMetrics.ISize(lineWM) += framePadding.IStart(frameWM);
  }

  /*
   * We want to only apply the end border and padding if we're the last
   * continuation and either not in an {ib} split or the last part of it.  To
   * be the last continuation we have to be complete (so that we won't get a
   * next-in-flow) and have no non-fluid continuations on our continuation
   * chain.  For box-decoration-break:clone we always apply the end border and
   * padding since all continuations have them.
   */
  if ((aStatus.IsComplete() &&
       !LastInFlow()->GetNextContinuation() &&
       !FrameIsNonLastInIBSplit()) ||
      boxDecorationBreakClone) {
    aMetrics.ISize(lineWM) += framePadding.IEnd(frameWM);
  }

  nsLayoutUtils::SetBSizeFromFontMetrics(this, aMetrics,
                                         framePadding, lineWM, frameWM);

  // For now our overflow area is zero. The real value will be
  // computed in |nsLineLayout::RelativePositionFrames|.
  aMetrics.mOverflowAreas.Clear();

#ifdef NOISY_FINAL_SIZE
  ListTag(stdout);
  printf(": metrics=%d,%d ascent=%d\n",
         aMetrics.Width(), aMetrics.Height(), aMetrics.TopAscent());
#endif
}
/* virtual */ nsresult
nsMathMLmpaddedFrame::Place(DrawTarget*          aDrawTarget,
                            bool                 aPlaceOrigin,
                            ReflowOutput& aDesiredSize)
{
  nsresult rv =
    nsMathMLContainerFrame::Place(aDrawTarget, false, aDesiredSize);
  if (NS_MATHML_HAS_ERROR(mPresentationData.flags) || NS_FAILED(rv)) {
    DidReflowChildren(PrincipalChildList().FirstChild());
    return rv;
  }

  nscoord height = aDesiredSize.BlockStartAscent();
  nscoord depth  = aDesiredSize.Height() - aDesiredSize.BlockStartAscent();
  // The REC says:
  //
  // "The lspace attribute ('leading' space) specifies the horizontal location
  // of the positioning point of the child content with respect to the
  // positioning point of the mpadded element. By default they coincide, and
  // therefore absolute values for lspace have the same effect as relative
  // values."
  //
  // "MathML renderers should ensure that, except for the effects of the
  // attributes, the relative spacing between the contents of the mpadded
  // element and surrounding MathML elements would not be modified by replacing
  // an mpadded element with an mrow element with the same content, even if
  // linebreaking occurs within the mpadded element."
  //
  // (http://www.w3.org/TR/MathML/chapter3.html#presm.mpadded)
  // 
  // "In those discussions, the terms leading and trailing are used to specify
  // a side of an object when which side to use depends on the directionality;
  // ie. leading means left in LTR but right in RTL."
  // (http://www.w3.org/TR/MathML/chapter3.html#presm.bidi.math)
  nscoord lspace = 0;
  // In MathML3, "width" will be the bounding box width and "advancewidth" will
  // refer "to the horizontal distance between the positioning point of the
  // mpadded and the positioning point for the following content".  MathML2
  // doesn't make the distinction.
  nscoord width  = aDesiredSize.Width();
  nscoord voffset = 0;

  int32_t pseudoUnit;
  nscoord initialWidth = width;
  float fontSizeInflation = nsLayoutUtils::FontSizeInflationFor(this);

  // update width
  pseudoUnit = (mWidthPseudoUnit == NS_MATHML_PSEUDO_UNIT_ITSELF)
             ? NS_MATHML_PSEUDO_UNIT_WIDTH : mWidthPseudoUnit;
  UpdateValue(mWidthSign, pseudoUnit, mWidth,
              aDesiredSize, width, fontSizeInflation);
  width = std::max(0, width);

  // update "height" (this is the ascent in the terminology of the REC)
  pseudoUnit = (mHeightPseudoUnit == NS_MATHML_PSEUDO_UNIT_ITSELF)
             ? NS_MATHML_PSEUDO_UNIT_HEIGHT : mHeightPseudoUnit;
  UpdateValue(mHeightSign, pseudoUnit, mHeight,
              aDesiredSize, height, fontSizeInflation);
  height = std::max(0, height);

  // update "depth" (this is the descent in the terminology of the REC)
  pseudoUnit = (mDepthPseudoUnit == NS_MATHML_PSEUDO_UNIT_ITSELF)
             ? NS_MATHML_PSEUDO_UNIT_DEPTH : mDepthPseudoUnit;
  UpdateValue(mDepthSign, pseudoUnit, mDepth,
              aDesiredSize, depth, fontSizeInflation);
  depth = std::max(0, depth);

  // update lspace
  if (mLeadingSpacePseudoUnit != NS_MATHML_PSEUDO_UNIT_ITSELF) {
    pseudoUnit = mLeadingSpacePseudoUnit;
    UpdateValue(mLeadingSpaceSign, pseudoUnit, mLeadingSpace,
                aDesiredSize, lspace, fontSizeInflation);
  }

  // update voffset
  if (mVerticalOffsetPseudoUnit != NS_MATHML_PSEUDO_UNIT_ITSELF) {
    pseudoUnit = mVerticalOffsetPseudoUnit;
    UpdateValue(mVerticalOffsetSign, pseudoUnit, mVerticalOffset,
                aDesiredSize, voffset, fontSizeInflation);
  }
  // do the padding now that we have everything
  // The idea here is to maintain the invariant that <mpadded>...</mpadded> (i.e.,
  // with no attributes) looks the same as <mrow>...</mrow>. But when there are
  // attributes, tweak our metrics and move children to achieve the desired visual
  // effects.

  if ((StyleVisibility()->mDirection ?
       mWidthSign : mLeadingSpaceSign) != NS_MATHML_SIGN_INVALID) {
    // there was padding on the left. dismiss the left italic correction now
    // (so that our parent won't correct us)
    mBoundingMetrics.leftBearing = 0;
  }

  if ((StyleVisibility()->mDirection ?
       mLeadingSpaceSign : mWidthSign) != NS_MATHML_SIGN_INVALID) {
    // there was padding on the right. dismiss the right italic correction now
    // (so that our parent won't correct us)
    mBoundingMetrics.width = width;
    mBoundingMetrics.rightBearing = mBoundingMetrics.width;
  }

  nscoord dx = (StyleVisibility()->mDirection ?
                width - initialWidth - lspace : lspace);
    
  aDesiredSize.SetBlockStartAscent(height);
  aDesiredSize.Width() = mBoundingMetrics.width;
  aDesiredSize.Height() = depth + aDesiredSize.BlockStartAscent();
  mBoundingMetrics.ascent = height;
  mBoundingMetrics.descent = depth;
  aDesiredSize.mBoundingMetrics = mBoundingMetrics;

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

  if (aPlaceOrigin) {
    // Finish reflowing child frames, positioning their origins.
    PositionRowChildFrames(dx, aDesiredSize.BlockStartAscent() - voffset);
  }

  return NS_OK;
}
/* virtual */ nsresult
nsMathMLmencloseFrame::PlaceInternal(DrawTarget*          aDrawTarget,
                                     bool                 aPlaceOrigin,
                                     ReflowOutput& aDesiredSize,
                                     bool                 aWidthOnly)
{
  ///////////////
  // Measure the size of our content using the base class to format like an
  // inferred mrow.
  ReflowOutput baseSize(aDesiredSize.GetWritingMode());
  nsresult rv =
    nsMathMLContainerFrame::Place(aDrawTarget, false, baseSize);

  if (NS_MATHML_HAS_ERROR(mPresentationData.flags) || NS_FAILED(rv)) {
      DidReflowChildren(PrincipalChildList().FirstChild());
      return rv;
    }

  nsBoundingMetrics bmBase = baseSize.mBoundingMetrics;
  nscoord dx_left = 0, dx_right = 0;
  nsBoundingMetrics bmLongdivChar, bmRadicalChar;
  nscoord radicalAscent = 0, radicalDescent = 0;
  nscoord longdivAscent = 0, longdivDescent = 0;
  nscoord psi = 0;
  nscoord leading = 0;

  ///////////////
  // Thickness of bars and font metrics
  nscoord onePixel = nsPresContext::CSSPixelsToAppUnits(1);

  float fontSizeInflation = nsLayoutUtils::FontSizeInflationFor(this);
  RefPtr<nsFontMetrics> fm =
    nsLayoutUtils::GetFontMetricsForFrame(this, fontSizeInflation);
  GetRuleThickness(aDrawTarget, fm, mRuleThickness);
  if (mRuleThickness < onePixel) {
    mRuleThickness = onePixel;
  }

  char16_t one = '1';
  nsBoundingMetrics bmOne =
    nsLayoutUtils::AppUnitBoundsOfString(&one, 1, *fm, aDrawTarget);

  ///////////////
  // General rules: the menclose element takes the size of the enclosed content.
  // We add a padding when needed.

  // determine padding & psi
  nscoord padding = 3 * mRuleThickness;
  nscoord delta = padding % onePixel;
  if (delta)
    padding += onePixel - delta; // round up

  if (IsToDraw(NOTATION_LONGDIV) || IsToDraw(NOTATION_RADICAL)) {
    GetRadicalParameters(fm, StyleFont()->mMathDisplay ==
                         NS_MATHML_DISPLAYSTYLE_BLOCK,
                         mRadicalRuleThickness, leading, psi);

    // make sure that the rule appears on on screen
    if (mRadicalRuleThickness < onePixel) {
      mRadicalRuleThickness = onePixel;
    }

    // adjust clearance psi to get an exact number of pixels -- this
    // gives a nicer & uniform look on stacked radicals (bug 130282)
    delta = psi % onePixel;
    if (delta) {
      psi += onePixel - delta; // round up
    }
  }

  // Set horizontal parameters
  if (IsToDraw(NOTATION_ROUNDEDBOX) ||
      IsToDraw(NOTATION_TOP) ||
      IsToDraw(NOTATION_LEFT) ||
      IsToDraw(NOTATION_BOTTOM) ||
      IsToDraw(NOTATION_CIRCLE))
    dx_left = padding;

  if (IsToDraw(NOTATION_ROUNDEDBOX) ||
      IsToDraw(NOTATION_TOP) ||
      IsToDraw(NOTATION_RIGHT) ||
      IsToDraw(NOTATION_BOTTOM) ||
      IsToDraw(NOTATION_CIRCLE))
    dx_right = padding;

  // Set vertical parameters
  if (IsToDraw(NOTATION_RIGHT) ||
      IsToDraw(NOTATION_LEFT) ||
      IsToDraw(NOTATION_UPDIAGONALSTRIKE) ||
      IsToDraw(NOTATION_UPDIAGONALARROW) ||
      IsToDraw(NOTATION_DOWNDIAGONALSTRIKE) ||
      IsToDraw(NOTATION_VERTICALSTRIKE) ||
      IsToDraw(NOTATION_CIRCLE) ||
      IsToDraw(NOTATION_ROUNDEDBOX) ||
      IsToDraw(NOTATION_RADICAL) ||
      IsToDraw(NOTATION_LONGDIV) ||
      IsToDraw(NOTATION_PHASORANGLE)) {
      // set a minimal value for the base height
      bmBase.ascent = std::max(bmOne.ascent, bmBase.ascent);
      bmBase.descent = std::max(0, bmBase.descent);
  }

  mBoundingMetrics.ascent = bmBase.ascent;
  mBoundingMetrics.descent = bmBase.descent;
    
  if (IsToDraw(NOTATION_ROUNDEDBOX) ||
      IsToDraw(NOTATION_TOP) ||
      IsToDraw(NOTATION_LEFT) ||
      IsToDraw(NOTATION_RIGHT) ||
      IsToDraw(NOTATION_CIRCLE))
    mBoundingMetrics.ascent += padding;
  
  if (IsToDraw(NOTATION_ROUNDEDBOX) ||
      IsToDraw(NOTATION_LEFT) ||
      IsToDraw(NOTATION_RIGHT) ||
      IsToDraw(NOTATION_BOTTOM) ||
      IsToDraw(NOTATION_CIRCLE))
    mBoundingMetrics.descent += padding;

   ///////////////
   // phasorangle notation
  if (IsToDraw(NOTATION_PHASORANGLE)) {
    nscoord phasorangleWidth = kPhasorangleWidth * mRuleThickness;
    // Update horizontal parameters
    dx_left = std::max(dx_left, phasorangleWidth);
  }

  ///////////////
  // updiagonal arrow notation. We need enough space at the top right corner to
  // draw the arrow head.
  if (IsToDraw(NOTATION_UPDIAGONALARROW)) {
    // This is an estimate, see nsDisplayNotation::Paint for the exact head size
    nscoord arrowHeadSize = kArrowHeadSize * mRuleThickness;

    // We want that the arrow shaft strikes the menclose content and that the
    // arrow head does not overlap with that content. Hence we add some space
    // on the right. We don't add space on the top but only ensure that the
    // ascent is large enough.
    dx_right = std::max(dx_right, arrowHeadSize);
    mBoundingMetrics.ascent = std::max(mBoundingMetrics.ascent, arrowHeadSize);
  }

  ///////////////
  // circle notation: we don't want the ellipse to overlap the enclosed
  // content. Hence, we need to increase the size of the bounding box by a
  // factor of at least sqrt(2).
  if (IsToDraw(NOTATION_CIRCLE)) {
    double ratio = (sqrt(2.0) - 1.0) / 2.0;
    nscoord padding2;

    // Update horizontal parameters
    padding2 = ratio * bmBase.width;

    dx_left = std::max(dx_left, padding2);
    dx_right = std::max(dx_right, padding2);

    // Update vertical parameters
    padding2 = ratio * (bmBase.ascent + bmBase.descent);

    mBoundingMetrics.ascent = std::max(mBoundingMetrics.ascent,
                                     bmBase.ascent + padding2);
    mBoundingMetrics.descent = std::max(mBoundingMetrics.descent,
                                      bmBase.descent + padding2);
  }

  ///////////////
  // longdiv notation:
  if (IsToDraw(NOTATION_LONGDIV)) {
    if (aWidthOnly) {
        nscoord longdiv_width = mMathMLChar[mLongDivCharIndex].
          GetMaxWidth(PresContext(), aDrawTarget, fontSizeInflation);

        // Update horizontal parameters
        dx_left = std::max(dx_left, longdiv_width);
    } else {
      // Stretch the parenthesis to the appropriate height if it is not
      // big enough.
      nsBoundingMetrics contSize = bmBase;
      contSize.ascent = mRuleThickness;
      contSize.descent = bmBase.ascent + bmBase.descent + psi;

      // height(longdiv) should be >= height(base) + psi + mRuleThickness
      mMathMLChar[mLongDivCharIndex].Stretch(PresContext(), aDrawTarget,
                                             fontSizeInflation,
                                             NS_STRETCH_DIRECTION_VERTICAL,
                                             contSize, bmLongdivChar,
                                             NS_STRETCH_LARGER, false);
      mMathMLChar[mLongDivCharIndex].GetBoundingMetrics(bmLongdivChar);

      // Update horizontal parameters
      dx_left = std::max(dx_left, bmLongdivChar.width);

      // Update vertical parameters
      longdivAscent = bmBase.ascent + psi + mRuleThickness;
      longdivDescent = std::max(bmBase.descent,
                              (bmLongdivChar.ascent + bmLongdivChar.descent -
                               longdivAscent));

      mBoundingMetrics.ascent = std::max(mBoundingMetrics.ascent,
                                       longdivAscent);
      mBoundingMetrics.descent = std::max(mBoundingMetrics.descent,
                                        longdivDescent);
    }
  }

  ///////////////
  // radical notation:
  if (IsToDraw(NOTATION_RADICAL)) {
    nscoord *dx_leading = StyleVisibility()->mDirection ? &dx_right : &dx_left;
    
    if (aWidthOnly) {
      nscoord radical_width = mMathMLChar[mRadicalCharIndex].
        GetMaxWidth(PresContext(), aDrawTarget, fontSizeInflation);
      
      // Update horizontal parameters
      *dx_leading = std::max(*dx_leading, radical_width);
    } else {
      // Stretch the radical symbol to the appropriate height if it is not
      // big enough.
      nsBoundingMetrics contSize = bmBase;
      contSize.ascent = mRadicalRuleThickness;
      contSize.descent = bmBase.ascent + bmBase.descent + psi;

      // height(radical) should be >= height(base) + psi + mRadicalRuleThickness
      mMathMLChar[mRadicalCharIndex].Stretch(PresContext(), aDrawTarget,
                                             fontSizeInflation,
                                             NS_STRETCH_DIRECTION_VERTICAL,
                                             contSize, bmRadicalChar,
                                             NS_STRETCH_LARGER,
                                             StyleVisibility()->mDirection);
      mMathMLChar[mRadicalCharIndex].GetBoundingMetrics(bmRadicalChar);

      // Update horizontal parameters
      *dx_leading = std::max(*dx_leading, bmRadicalChar.width);

      // Update vertical parameters
      radicalAscent = bmBase.ascent + psi + mRadicalRuleThickness;
      radicalDescent = std::max(bmBase.descent,
                              (bmRadicalChar.ascent + bmRadicalChar.descent -
                               radicalAscent));

      mBoundingMetrics.ascent = std::max(mBoundingMetrics.ascent,
                                       radicalAscent);
      mBoundingMetrics.descent = std::max(mBoundingMetrics.descent,
                                        radicalDescent);
    }
  }

  ///////////////
  //
  if (IsToDraw(NOTATION_CIRCLE) ||
      IsToDraw(NOTATION_ROUNDEDBOX) ||
      (IsToDraw(NOTATION_LEFT) && IsToDraw(NOTATION_RIGHT))) {
    // center the menclose around the content (horizontally)
    dx_left = dx_right = std::max(dx_left, dx_right);
  }

  ///////////////
  // The maximum size is now computed: set the remaining parameters
  mBoundingMetrics.width = dx_left + bmBase.width + dx_right;

  mBoundingMetrics.leftBearing = std::min(0, dx_left + bmBase.leftBearing);
  mBoundingMetrics.rightBearing =
    std::max(mBoundingMetrics.width, dx_left + bmBase.rightBearing);
  
  aDesiredSize.Width() = mBoundingMetrics.width;

  aDesiredSize.SetBlockStartAscent(std::max(mBoundingMetrics.ascent,
                                            baseSize.BlockStartAscent()));
  aDesiredSize.Height() = aDesiredSize.BlockStartAscent() +
    std::max(mBoundingMetrics.descent,
             baseSize.Height() - baseSize.BlockStartAscent());

  if (IsToDraw(NOTATION_LONGDIV) || IsToDraw(NOTATION_RADICAL)) {
    nscoord desiredSizeAscent = aDesiredSize.BlockStartAscent();
    nscoord desiredSizeDescent = aDesiredSize.Height() -
                                 aDesiredSize.BlockStartAscent();
    
    if (IsToDraw(NOTATION_LONGDIV)) {
      desiredSizeAscent = std::max(desiredSizeAscent,
                                 longdivAscent + leading);
      desiredSizeDescent = std::max(desiredSizeDescent,
                                  longdivDescent + mRuleThickness);
    }
    
    if (IsToDraw(NOTATION_RADICAL)) {
      desiredSizeAscent = std::max(desiredSizeAscent,
                                 radicalAscent + leading);
      desiredSizeDescent = std::max(desiredSizeDescent,
                                    radicalDescent + mRadicalRuleThickness);
    }

    aDesiredSize.SetBlockStartAscent(desiredSizeAscent);
    aDesiredSize.Height() = desiredSizeAscent + desiredSizeDescent;
  }
    
  if (IsToDraw(NOTATION_CIRCLE) ||
      IsToDraw(NOTATION_ROUNDEDBOX) ||
      (IsToDraw(NOTATION_TOP) && IsToDraw(NOTATION_BOTTOM))) {
    // center the menclose around the content (vertically)
    nscoord dy = std::max(aDesiredSize.BlockStartAscent() - bmBase.ascent,
                          aDesiredSize.Height() -
                          aDesiredSize.BlockStartAscent() - bmBase.descent);

    aDesiredSize.SetBlockStartAscent(bmBase.ascent + dy);
    aDesiredSize.Height() = aDesiredSize.BlockStartAscent() + bmBase.descent + dy;
  }

  // Update mBoundingMetrics ascent/descent
  if (IsToDraw(NOTATION_TOP) ||
      IsToDraw(NOTATION_RIGHT) ||
      IsToDraw(NOTATION_LEFT) ||
      IsToDraw(NOTATION_UPDIAGONALSTRIKE) ||
      IsToDraw(NOTATION_UPDIAGONALARROW) ||
      IsToDraw(NOTATION_DOWNDIAGONALSTRIKE) ||
      IsToDraw(NOTATION_VERTICALSTRIKE) ||
      IsToDraw(NOTATION_CIRCLE) ||
      IsToDraw(NOTATION_ROUNDEDBOX))
    mBoundingMetrics.ascent = aDesiredSize.BlockStartAscent();
  
  if (IsToDraw(NOTATION_BOTTOM) ||
      IsToDraw(NOTATION_RIGHT) ||
      IsToDraw(NOTATION_LEFT) ||
      IsToDraw(NOTATION_UPDIAGONALSTRIKE) ||
      IsToDraw(NOTATION_UPDIAGONALARROW) ||
      IsToDraw(NOTATION_DOWNDIAGONALSTRIKE) ||
      IsToDraw(NOTATION_VERTICALSTRIKE) ||
      IsToDraw(NOTATION_CIRCLE) ||
      IsToDraw(NOTATION_ROUNDEDBOX))
    mBoundingMetrics.descent = aDesiredSize.Height() - aDesiredSize.BlockStartAscent();

  // phasorangle notation:
  // move up from the bottom by the angled line height
  if (IsToDraw(NOTATION_PHASORANGLE))
    mBoundingMetrics.ascent = std::max(mBoundingMetrics.ascent, 2 * kPhasorangleWidth * mRuleThickness - mBoundingMetrics.descent);
  
  aDesiredSize.mBoundingMetrics = mBoundingMetrics;
  
  mReference.x = 0;
  mReference.y = aDesiredSize.BlockStartAscent();

  if (aPlaceOrigin) {
    //////////////////
    // Set position and size of MathMLChars
    if (IsToDraw(NOTATION_LONGDIV))
      mMathMLChar[mLongDivCharIndex].SetRect(nsRect(dx_left -
                                                    bmLongdivChar.width,
                                                    aDesiredSize.BlockStartAscent() -
                                                    longdivAscent,
                                                    bmLongdivChar.width,
                                                    bmLongdivChar.ascent +
                                                    bmLongdivChar.descent));

    if (IsToDraw(NOTATION_RADICAL)) {
      nscoord dx = (StyleVisibility()->mDirection ?
                    dx_left + bmBase.width : dx_left - bmRadicalChar.width);

      mMathMLChar[mRadicalCharIndex].SetRect(nsRect(dx,
                                                    aDesiredSize.BlockStartAscent() -
                                                    radicalAscent,
                                                    bmRadicalChar.width,
                                                    bmRadicalChar.ascent +
                                                    bmRadicalChar.descent));
    }

    mContentWidth = bmBase.width;

    //////////////////
    // Finish reflowing child frames
    PositionRowChildFrames(dx_left, aDesiredSize.BlockStartAscent());
  }

  return NS_OK;
}
Exemplo n.º 7
0
void
nsTableCellFrame::Reflow(nsPresContext*           aPresContext,
                         ReflowOutput&     aDesiredSize,
                         const ReflowInput& aReflowInput,
                         nsReflowStatus&          aStatus)
{
  MarkInReflow();
  DO_GLOBAL_REFLOW_COUNT("nsTableCellFrame");
  DISPLAY_REFLOW(aPresContext, this, aReflowInput, aDesiredSize, aStatus);

  if (aReflowInput.mFlags.mSpecialBSizeReflow) {
    FirstInFlow()->AddStateBits(NS_TABLE_CELL_HAD_SPECIAL_REFLOW);
  }

  // see if a special bsize reflow needs to occur due to having a pct height
  nsTableFrame::CheckRequestSpecialBSizeReflow(aReflowInput);

  aStatus = NS_FRAME_COMPLETE;
  WritingMode wm = aReflowInput.GetWritingMode();
  LogicalSize availSize(wm, aReflowInput.AvailableISize(),
                            aReflowInput.AvailableBSize());

  LogicalMargin borderPadding = aReflowInput.ComputedLogicalPadding();
  LogicalMargin border = GetBorderWidth(wm);
  borderPadding += border;

  // reduce available space by insets, if we're in a constrained situation
  availSize.ISize(wm) -= borderPadding.IStartEnd(wm);
  if (NS_UNCONSTRAINEDSIZE != availSize.BSize(wm)) {
    availSize.BSize(wm) -= borderPadding.BStartEnd(wm);
  }

  // Try to reflow the child into the available space. It might not
  // fit or might need continuing.
  if (availSize.BSize(wm) < 0) {
    availSize.BSize(wm) = 1;
  }

  ReflowOutput kidSize(wm, aDesiredSize.mFlags);
  kidSize.ClearSize();
  SetPriorAvailISize(aReflowInput.AvailableISize());
  nsIFrame* firstKid = mFrames.FirstChild();
  NS_ASSERTION(firstKid, "Frame construction error, a table cell always has an inner cell frame");
  nsTableFrame* tableFrame = GetTableFrame();

  if (aReflowInput.mFlags.mSpecialBSizeReflow) {
    const_cast<ReflowInput&>(aReflowInput).
      SetComputedBSize(BSize(wm) - borderPadding.BStartEnd(wm));
    DISPLAY_REFLOW_CHANGE();
  }
  else if (aPresContext->IsPaginated()) {
    nscoord computedUnpaginatedBSize =
      CalcUnpaginatedBSize((nsTableCellFrame&)*this,
                           *tableFrame, borderPadding.BStartEnd(wm));
    if (computedUnpaginatedBSize > 0) {
      const_cast<ReflowInput&>(aReflowInput).SetComputedBSize(computedUnpaginatedBSize);
      DISPLAY_REFLOW_CHANGE();
    }
  }
  else {
    SetHasPctOverBSize(false);
  }

  WritingMode kidWM = firstKid->GetWritingMode();
  ReflowInput kidReflowInput(aPresContext, aReflowInput, firstKid,
                                   availSize.ConvertTo(kidWM, wm));

  // Don't be a percent height observer if we're in the middle of
  // special-bsize reflow, in case we get an accidental NotifyPercentBSize()
  // call (which we shouldn't honor during special-bsize reflow)
  if (!aReflowInput.mFlags.mSpecialBSizeReflow) {
    // mPercentBSizeObserver is for children of cells in quirks mode,
    // but only those than are tables in standards mode.  NeedsToObserve
    // will determine how far this is propagated to descendants.
    kidReflowInput.mPercentBSizeObserver = this;
  }
  // Don't propagate special bsize reflow state to our kids
  kidReflowInput.mFlags.mSpecialBSizeReflow = false;

  if (aReflowInput.mFlags.mSpecialBSizeReflow ||
      FirstInFlow()->HasAnyStateBits(NS_TABLE_CELL_HAD_SPECIAL_REFLOW)) {
    // We need to force the kid to have mBResize set if we've had a
    // special reflow in the past, since the non-special reflow needs to
    // resize back to what it was without the special bsize reflow.
    kidReflowInput.SetBResize(true);
  }

  nsSize containerSize =
    aReflowInput.ComputedSizeAsContainerIfConstrained();

  LogicalPoint kidOrigin(wm, borderPadding.IStart(wm),
                         borderPadding.BStart(wm));
  nsRect origRect = firstKid->GetRect();
  nsRect origVisualOverflow = firstKid->GetVisualOverflowRect();
  bool firstReflow = firstKid->HasAnyStateBits(NS_FRAME_FIRST_REFLOW);

  ReflowChild(firstKid, aPresContext, kidSize, kidReflowInput,
              wm, kidOrigin, containerSize, 0, aStatus);
  if (NS_FRAME_OVERFLOW_IS_INCOMPLETE(aStatus)) {
    // Don't pass OVERFLOW_INCOMPLETE through tables until they can actually handle it
    //XXX should paginate overflow as overflow, but not in this patch (bug 379349)
    NS_FRAME_SET_INCOMPLETE(aStatus);
    printf("Set table cell incomplete %p\n", static_cast<void*>(this));
  }

  // XXXbz is this invalidate actually needed, really?
  if (HasAnyStateBits(NS_FRAME_IS_DIRTY)) {
    InvalidateFrameSubtree();
  }

#ifdef DEBUG
  DebugCheckChildSize(firstKid, kidSize);
#endif

  // 0 dimensioned cells need to be treated specially in Standard/NavQuirks mode
  // see testcase "emptyCells.html"
  nsIFrame* prevInFlow = GetPrevInFlow();
  bool isEmpty;
  if (prevInFlow) {
    isEmpty = static_cast<nsTableCellFrame*>(prevInFlow)->GetContentEmpty();
  } else {
    isEmpty = !CellHasVisibleContent(kidSize.Height(), tableFrame, firstKid);
  }
  SetContentEmpty(isEmpty);

  // Place the child
  FinishReflowChild(firstKid, aPresContext, kidSize, &kidReflowInput,
                    wm, kidOrigin, containerSize, 0);

  nsTableFrame::InvalidateTableFrame(firstKid, origRect, origVisualOverflow,
                                     firstReflow);

  // first, compute the bsize which can be set w/o being restricted by
  // available bsize
  LogicalSize cellSize(wm);
  cellSize.BSize(wm) = kidSize.BSize(wm);

  if (NS_UNCONSTRAINEDSIZE != cellSize.BSize(wm)) {
    cellSize.BSize(wm) += borderPadding.BStartEnd(wm);
  }

  // next determine the cell's isize
  cellSize.ISize(wm) = kidSize.ISize(wm);      // at this point, we've factored in the cell's style attributes

  // factor in border and padding
  if (NS_UNCONSTRAINEDSIZE != cellSize.ISize(wm)) {
    cellSize.ISize(wm) += borderPadding.IStartEnd(wm);
  }

  // set the cell's desired size and max element size
  aDesiredSize.SetSize(wm, cellSize);

  // the overflow area will be computed when BlockDirAlignChild() gets called

  if (aReflowInput.mFlags.mSpecialBSizeReflow) {
    if (aDesiredSize.BSize(wm) > BSize(wm)) {
      // set a bit indicating that the pct bsize contents exceeded
      // the height that they could honor in the pass 2 reflow
      SetHasPctOverBSize(true);
    }
    if (NS_UNCONSTRAINEDSIZE == aReflowInput.AvailableBSize()) {
      aDesiredSize.BSize(wm) = BSize(wm);
    }
  }

  // If our parent is in initial reflow, it'll handle invalidating our
  // entire overflow rect.
  if (!GetParent()->HasAnyStateBits(NS_FRAME_FIRST_REFLOW) &&
      nsSize(aDesiredSize.Width(), aDesiredSize.Height()) != mRect.Size()) {
    InvalidateFrame();
  }

  // remember the desired size for this reflow
  SetDesiredSize(aDesiredSize);

  // Any absolutely-positioned children will get reflowed in
  // nsFrame::FixupPositionedTableParts in another pass, so propagate our
  // dirtiness to them before our parent clears our dirty bits.
  PushDirtyBitToAbsoluteFrames();

  NS_FRAME_SET_TRUNCATION(aStatus, aReflowInput, aDesiredSize);
}
void
nsSubDocumentFrame::Reflow(nsPresContext*           aPresContext,
                           ReflowOutput&     aDesiredSize,
                           const ReflowInput& aReflowInput,
                           nsReflowStatus&          aStatus)
{
  MarkInReflow();
  DO_GLOBAL_REFLOW_COUNT("nsSubDocumentFrame");
  DISPLAY_REFLOW(aPresContext, this, aReflowInput, aDesiredSize, aStatus);
  NS_FRAME_TRACE(NS_FRAME_TRACE_CALLS,
     ("enter nsSubDocumentFrame::Reflow: maxSize=%d,%d",
      aReflowInput.AvailableWidth(), aReflowInput.AvailableHeight()));

  NS_ASSERTION(aReflowInput.ComputedWidth() != NS_UNCONSTRAINEDSIZE,
               "Shouldn't have unconstrained stuff here "
               "thanks to the rules of reflow");
  NS_ASSERTION(NS_INTRINSICSIZE != aReflowInput.ComputedHeight(),
               "Shouldn't have unconstrained stuff here "
               "thanks to ComputeAutoSize");

  aStatus = NS_FRAME_COMPLETE;

  NS_ASSERTION(mContent->GetPrimaryFrame() == this,
               "Shouldn't happen");

  // XUL <iframe> or <browser>, or HTML <iframe>, <object> or <embed>
  aDesiredSize.SetSize(aReflowInput.GetWritingMode(),
                       aReflowInput.ComputedSizeWithBorderPadding());

  // "offset" is the offset of our content area from our frame's
  // top-left corner.
  nsPoint offset = nsPoint(aReflowInput.ComputedPhysicalBorderPadding().left,
                           aReflowInput.ComputedPhysicalBorderPadding().top);

  if (mInnerView) {
    const nsMargin& bp = aReflowInput.ComputedPhysicalBorderPadding();
    nsSize innerSize(aDesiredSize.Width() - bp.LeftRight(),
                     aDesiredSize.Height() - bp.TopBottom());

    // Size & position the view according to 'object-fit' & 'object-position'.
    nsIFrame* subDocRoot = ObtainIntrinsicSizeFrame();
    IntrinsicSize intrinsSize;
    nsSize intrinsRatio;
    if (subDocRoot) {
      intrinsSize = subDocRoot->GetIntrinsicSize();
      intrinsRatio = subDocRoot->GetIntrinsicRatio();
    }
    nsRect destRect =
      nsLayoutUtils::ComputeObjectDestRect(nsRect(offset, innerSize),
                                           intrinsSize, intrinsRatio,
                                           StylePosition());

    nsViewManager* vm = mInnerView->GetViewManager();
    vm->MoveViewTo(mInnerView, destRect.x, destRect.y);
    vm->ResizeView(mInnerView, nsRect(nsPoint(0, 0), destRect.Size()), true);
  }

  aDesiredSize.SetOverflowAreasToDesiredBounds();
  if (!ShouldClipSubdocument()) {
    nsIFrame* subdocRootFrame = GetSubdocumentRootFrame();
    if (subdocRootFrame) {
      aDesiredSize.mOverflowAreas.UnionWith(subdocRootFrame->GetOverflowAreas() + offset);
    }
  }

  FinishAndStoreOverflow(&aDesiredSize);

  if (!aPresContext->IsPaginated() && !mPostedReflowCallback) {
    PresContext()->PresShell()->PostReflowCallback(this);
    mPostedReflowCallback = true;
  }

  NS_FRAME_TRACE(NS_FRAME_TRACE_CALLS,
     ("exit nsSubDocumentFrame::Reflow: size=%d,%d status=%x",
      aDesiredSize.Width(), aDesiredSize.Height(), aStatus));

  NS_FRAME_SET_TRUNCATION(aStatus, aReflowInput, aDesiredSize);
}
void
nsMathMLmrootFrame::Reflow(nsPresContext*          aPresContext,
                           ReflowOutput&     aDesiredSize,
                           const ReflowInput& aReflowInput,
                           nsReflowStatus&          aStatus)
{
  MarkInReflow();
  nsReflowStatus childStatus;

  mPresentationData.flags &= ~NS_MATHML_ERROR;
  aDesiredSize.ClearSize();
  aDesiredSize.SetBlockStartAscent(0);

  nsBoundingMetrics bmSqr, bmBase, bmIndex;
  DrawTarget* drawTarget = aReflowInput.mRenderingContext->GetDrawTarget();

  //////////////////
  // Reflow Children

  int32_t count = 0;
  nsIFrame* baseFrame = nullptr;
  nsIFrame* indexFrame = nullptr;
  ReflowOutput baseSize(aReflowInput);
  ReflowOutput indexSize(aReflowInput);
  nsIFrame* childFrame = mFrames.FirstChild();
  while (childFrame) {
    // ask our children to compute their bounding metrics 
    ReflowOutput childDesiredSize(aReflowInput,
                                         aDesiredSize.mFlags
                                         | NS_REFLOW_CALC_BOUNDING_METRICS);
    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");
    if (0 == count) {
      // base 
      baseFrame = childFrame;
      baseSize = childDesiredSize;
      bmBase = childDesiredSize.mBoundingMetrics;
    }
    else if (1 == count) {
      // index
      indexFrame = childFrame;
      indexSize = childDesiredSize;
      bmIndex = childDesiredSize.mBoundingMetrics;
    }
    count++;
    childFrame = childFrame->GetNextSibling();
  }
  if (2 != count) {
    // report an error, encourage people to get their markups in order
    ReportChildCountError();
    ReflowError(drawTarget, aDesiredSize);
    aStatus.Reset();
    NS_FRAME_SET_TRUNCATION(aStatus, aReflowInput, aDesiredSize);
    // Call DidReflow() for the child frames we successfully did reflow.
    DidReflowChildren(mFrames.FirstChild(), childFrame);
    return;
  }

  ////////////
  // Prepare the radical symbol and the overline bar

  float fontSizeInflation = nsLayoutUtils::FontSizeInflationFor(this);
  RefPtr<nsFontMetrics> fm =
    nsLayoutUtils::GetFontMetricsForFrame(this, fontSizeInflation);

  nscoord ruleThickness, leading, psi;
  GetRadicalParameters(fm, StyleFont()->mMathDisplay ==
                       NS_MATHML_DISPLAYSTYLE_BLOCK,
                       ruleThickness, leading, psi);

  // built-in: adjust clearance psi to emulate \mathstrut using '1' (TexBook, p.131)
  char16_t one = '1';
  nsBoundingMetrics bmOne =
    nsLayoutUtils::AppUnitBoundsOfString(&one, 1, *fm, drawTarget);
  if (bmOne.ascent > bmBase.ascent)
    psi += bmOne.ascent - bmBase.ascent;

  // make sure that the rule appears on on screen
  nscoord onePixel = nsPresContext::CSSPixelsToAppUnits(1);
  if (ruleThickness < onePixel) {
    ruleThickness = onePixel;
  }

  // adjust clearance psi to get an exact number of pixels -- this
  // gives a nicer & uniform look on stacked radicals (bug 130282)
  nscoord delta = psi % onePixel;
  if (delta)
    psi += onePixel - delta; // round up

  // Stretch the radical symbol to the appropriate height if it is not big enough.
  nsBoundingMetrics contSize = bmBase;
  contSize.descent = bmBase.ascent + bmBase.descent + psi;
  contSize.ascent = ruleThickness;

  // height(radical) should be >= height(base) + psi + ruleThickness
  nsBoundingMetrics radicalSize;
  mSqrChar.Stretch(aPresContext, drawTarget,
                   fontSizeInflation,
                   NS_STRETCH_DIRECTION_VERTICAL, 
                   contSize, radicalSize,
                   NS_STRETCH_LARGER,
                   StyleVisibility()->mDirection);
  // radicalSize have changed at this point, and should match with
  // the bounding metrics of the char
  mSqrChar.GetBoundingMetrics(bmSqr);

  // Update the desired size for the container (like msqrt, index is not yet included)
  // the baseline will be that of the base.
  mBoundingMetrics.ascent = bmBase.ascent + psi + ruleThickness;
  mBoundingMetrics.descent = 
    std::max(bmBase.descent,
           (bmSqr.ascent + bmSqr.descent - mBoundingMetrics.ascent));
  mBoundingMetrics.width = bmSqr.width + bmBase.width;
  mBoundingMetrics.leftBearing = bmSqr.leftBearing;
  mBoundingMetrics.rightBearing = bmSqr.width + 
    std::max(bmBase.width, bmBase.rightBearing); // take also care of the rule

  aDesiredSize.SetBlockStartAscent(mBoundingMetrics.ascent + leading);
  aDesiredSize.Height() = aDesiredSize.BlockStartAscent() +
    std::max(baseSize.Height() - baseSize.BlockStartAscent(),
             mBoundingMetrics.descent + ruleThickness);
  aDesiredSize.Width() = mBoundingMetrics.width;

  /////////////
  // Re-adjust the desired size to include the index.
  
  // the index is raised by some fraction of the height
  // of the radical, see \mroot macro in App. B, TexBook
  float raiseIndexPercent = 0.6f;
  gfxFont* mathFont = fm->GetThebesFontGroup()->GetFirstMathFont();
  if (mathFont) {
    raiseIndexPercent = mathFont->MathTable()->
      Constant(gfxMathTable::RadicalDegreeBottomRaisePercent);
  }
  nscoord raiseIndexDelta = NSToCoordRound(raiseIndexPercent *
                                           (bmSqr.ascent + bmSqr.descent));
  nscoord indexRaisedAscent = mBoundingMetrics.ascent // top of radical 
    - (bmSqr.ascent + bmSqr.descent) // to bottom of radical
    + raiseIndexDelta + bmIndex.ascent + bmIndex.descent; // to top of raised index

  nscoord indexClearance = 0;
  if (mBoundingMetrics.ascent < indexRaisedAscent) {
    indexClearance = 
      indexRaisedAscent - mBoundingMetrics.ascent; // excess gap introduced by a tall index 
    mBoundingMetrics.ascent = indexRaisedAscent;
    nscoord descent = aDesiredSize.Height() - aDesiredSize.BlockStartAscent();
    aDesiredSize.SetBlockStartAscent(mBoundingMetrics.ascent + leading);
    aDesiredSize.Height() = aDesiredSize.BlockStartAscent() + descent;
  }

  nscoord dxIndex, dxSqr;
  GetRadicalXOffsets(bmIndex.width, bmSqr.width, fm, &dxIndex, &dxSqr);

  mBoundingMetrics.width = dxSqr + bmSqr.width + bmBase.width;
  mBoundingMetrics.leftBearing = 
    std::min(dxIndex + bmIndex.leftBearing, dxSqr + bmSqr.leftBearing);
  mBoundingMetrics.rightBearing = dxSqr + bmSqr.width +
    std::max(bmBase.width, bmBase.rightBearing);

  aDesiredSize.Width() = mBoundingMetrics.width;
  aDesiredSize.mBoundingMetrics = mBoundingMetrics;
  GatherAndStoreOverflow(&aDesiredSize);

  // place the index
  nscoord dx = dxIndex;
  nscoord dy = aDesiredSize.BlockStartAscent() -
    (indexRaisedAscent + indexSize.BlockStartAscent() - bmIndex.ascent);
  FinishReflowChild(indexFrame, aPresContext, indexSize, nullptr,
                    MirrorIfRTL(aDesiredSize.Width(), indexSize.Width(), dx),
                    dy, 0);

  // place the radical symbol and the radical bar
  dx = dxSqr;
  dy = indexClearance + leading; // leave a leading at the top
  mSqrChar.SetRect(nsRect(MirrorIfRTL(aDesiredSize.Width(), bmSqr.width, dx),
                          dy, bmSqr.width, bmSqr.ascent + bmSqr.descent));
  dx += bmSqr.width;
  mBarRect.SetRect(MirrorIfRTL(aDesiredSize.Width(), bmBase.width, dx),
                   dy, bmBase.width, ruleThickness);

  // place the base
  dy = aDesiredSize.BlockStartAscent() - baseSize.BlockStartAscent();
  FinishReflowChild(baseFrame, aPresContext, baseSize, nullptr,
                    MirrorIfRTL(aDesiredSize.Width(), baseSize.Width(), dx),
                    dy, 0);

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

  aStatus.Reset();
  NS_FRAME_SET_TRUNCATION(aStatus, aReflowInput, aDesiredSize);
}
/* virtual */ nsresult
nsMathMLmunderoverFrame::Place(DrawTarget*          aDrawTarget,
                               bool                 aPlaceOrigin,
                               ReflowOutput& aDesiredSize)
{
  float fontSizeInflation = nsLayoutUtils::FontSizeInflationFor(this);
  if (NS_MATHML_EMBELLISH_IS_MOVABLELIMITS(mEmbellishData.flags) &&
      StyleFont()->mMathDisplay == NS_MATHML_DISPLAYSTYLE_INLINE) {
    //place like sub sup or subsup
    if (mContent->IsMathMLElement(nsGkAtoms::munderover_)) {
      return nsMathMLmmultiscriptsFrame::PlaceMultiScript(PresContext(),
                                                          aDrawTarget,
                                                          aPlaceOrigin,
                                                          aDesiredSize,
                                                          this, 0, 0,
                                                          fontSizeInflation);
    } else if (mContent->IsMathMLElement( nsGkAtoms::munder_)) {
      return nsMathMLmmultiscriptsFrame::PlaceMultiScript(PresContext(),
                                                          aDrawTarget,
                                                          aPlaceOrigin,
                                                          aDesiredSize,
                                                          this, 0, 0,
                                                          fontSizeInflation);
    } else {
      NS_ASSERTION(mContent->IsMathMLElement(nsGkAtoms::mover_),
                   "mContent->NodeInfo()->NameAtom() not recognized");
      return nsMathMLmmultiscriptsFrame::PlaceMultiScript(PresContext(),
                                                          aDrawTarget,
                                                          aPlaceOrigin,
                                                          aDesiredSize,
                                                          this, 0, 0,
                                                          fontSizeInflation);
    }
    
  }

  ////////////////////////////////////
  // Get the children's desired sizes

  nsBoundingMetrics bmBase, bmUnder, bmOver;
  ReflowOutput baseSize(aDesiredSize.GetWritingMode());
  ReflowOutput underSize(aDesiredSize.GetWritingMode());
  ReflowOutput overSize(aDesiredSize.GetWritingMode());
  nsIFrame* overFrame = nullptr;
  nsIFrame* underFrame = nullptr;
  nsIFrame* baseFrame = mFrames.FirstChild();
  underSize.SetBlockStartAscent(0);
  overSize.SetBlockStartAscent(0);
  bool haveError = false;
  if (baseFrame) {
    if (mContent->IsAnyOfMathMLElements(nsGkAtoms::munder_,
                                        nsGkAtoms::munderover_)) {
      underFrame = baseFrame->GetNextSibling();
    } else if (mContent->IsMathMLElement(nsGkAtoms::mover_)) {
      overFrame = baseFrame->GetNextSibling();
    }
  }
  if (underFrame && mContent->IsMathMLElement(nsGkAtoms::munderover_)) {
    overFrame = underFrame->GetNextSibling();
  }
  
  if (mContent->IsMathMLElement(nsGkAtoms::munder_)) {
    if (!baseFrame || !underFrame || underFrame->GetNextSibling()) {
      // report an error, encourage people to get their markups in order
      haveError = true;
    }
  }
  if (mContent->IsMathMLElement(nsGkAtoms::mover_)) {
    if (!baseFrame || !overFrame || overFrame->GetNextSibling()) {
      // report an error, encourage people to get their markups in order
      haveError = true;
    }
  }
  if (mContent->IsMathMLElement(nsGkAtoms::munderover_)) {
    if (!baseFrame || !underFrame || !overFrame || overFrame->GetNextSibling()) {
      // report an error, encourage people to get their markups in order
      haveError = true;
    }
  }
  if (haveError) {
    if (aPlaceOrigin) {
      ReportChildCountError();
    }
    return ReflowError(aDrawTarget, aDesiredSize);
  }
  GetReflowAndBoundingMetricsFor(baseFrame, baseSize, bmBase);
  if (underFrame) {
    GetReflowAndBoundingMetricsFor(underFrame, underSize, bmUnder);
  }
  if (overFrame) {
    GetReflowAndBoundingMetricsFor(overFrame, overSize, bmOver);
  }

  nscoord onePixel = nsPresContext::CSSPixelsToAppUnits(1);

  ////////////////////
  // Place Children

  RefPtr<nsFontMetrics> fm =
    nsLayoutUtils::GetFontMetricsForFrame(this, fontSizeInflation);

  nscoord xHeight = fm->XHeight();
  nscoord oneDevPixel = fm->AppUnitsPerDevPixel();
  gfxFont* mathFont = fm->GetThebesFontGroup()->GetFirstMathFont();

  nscoord ruleThickness;
  GetRuleThickness (aDrawTarget, fm, ruleThickness);

  nscoord correction = 0;
  GetItalicCorrection (bmBase, correction);

  // there are 2 different types of placement depending on 
  // whether we want an accented under or not

  nscoord underDelta1 = 0; // gap between base and underscript
  nscoord underDelta2 = 0; // extra space beneath underscript

  if (!NS_MATHML_EMBELLISH_IS_ACCENTUNDER(mEmbellishData.flags)) {
    // Rule 13a, App. G, TeXbook
    nscoord bigOpSpacing2, bigOpSpacing4, bigOpSpacing5, dummy; 
    GetBigOpSpacings (fm, 
                      dummy, bigOpSpacing2, 
                      dummy, bigOpSpacing4, 
                      bigOpSpacing5);
    if (mathFont) {
      // XXXfredw The Open Type MATH table has some StretchStack* parameters
      // that we may use when the base is a stretchy horizontal operator. See
      // bug 963131.
      bigOpSpacing2 =
        mathFont->GetMathConstant(gfxFontEntry::LowerLimitGapMin,
                                  oneDevPixel);
      bigOpSpacing4 =
        mathFont->GetMathConstant(gfxFontEntry::LowerLimitBaselineDropMin,
                                  oneDevPixel);
      bigOpSpacing5 = 0;
    }
    underDelta1 = std::max(bigOpSpacing2, (bigOpSpacing4 - bmUnder.ascent));
    underDelta2 = bigOpSpacing5;
  }
  else {
    // No corresponding rule in TeXbook - we are on our own here
    // XXX tune the gap delta between base and underscript 
    // XXX Should we use Rule 10 like \underline does?
    // XXXfredw Perhaps use the Underbar* parameters of the MATH table. See
    // bug 963125.
    underDelta1 = ruleThickness + onePixel/2;
    underDelta2 = ruleThickness;
  }
  // empty under?
  if (!(bmUnder.ascent + bmUnder.descent)) {
    underDelta1 = 0;
    underDelta2 = 0;
  }

  nscoord overDelta1 = 0; // gap between base and overscript
  nscoord overDelta2 = 0; // extra space above overscript

  if (!NS_MATHML_EMBELLISH_IS_ACCENTOVER(mEmbellishData.flags)) {    
    // Rule 13a, App. G, TeXbook
    // XXXfredw The Open Type MATH table has some StretchStack* parameters
    // that we may use when the base is a stretchy horizontal operator. See
    // bug 963131.
    nscoord bigOpSpacing1, bigOpSpacing3, bigOpSpacing5, dummy; 
    GetBigOpSpacings (fm, 
                      bigOpSpacing1, dummy, 
                      bigOpSpacing3, dummy, 
                      bigOpSpacing5);
    if (mathFont) {
      // XXXfredw The Open Type MATH table has some StretchStack* parameters
      // that we may use when the base is a stretchy horizontal operator. See
      // bug 963131.
      bigOpSpacing1 =
        mathFont->GetMathConstant(gfxFontEntry::UpperLimitGapMin,
                                  oneDevPixel);
      bigOpSpacing3 =
        mathFont->GetMathConstant(gfxFontEntry::UpperLimitBaselineRiseMin,
                                  oneDevPixel);
      bigOpSpacing5 = 0;
    }
    overDelta1 = std::max(bigOpSpacing1, (bigOpSpacing3 - bmOver.descent));
    overDelta2 = bigOpSpacing5;

    // XXX This is not a TeX rule... 
    // delta1 (as computed abvove) can become really big when bmOver.descent is
    // negative,  e.g., if the content is &OverBar. In such case, we use the height
    if (bmOver.descent < 0)    
      overDelta1 = std::max(bigOpSpacing1, (bigOpSpacing3 - (bmOver.ascent + bmOver.descent)));
  }
  else {
    // Rule 12, App. G, TeXbook
    // We are going to modify this rule to make it more general.
    // The idea behind Rule 12 in the TeXBook is to keep the accent
    // as close to the base as possible, while ensuring that the
    // distance between the *baseline* of the accent char and 
    // the *baseline* of the base is atleast x-height. 
    // The idea is that for normal use, we would like all the accents
    // on a line to line up atleast x-height above the baseline 
    // if possible. 
    // When the ascent of the base is >= x-height, 
    // the baseline of the accent char is placed just above the base
    // (specifically, the baseline of the accent char is placed 
    // above the baseline of the base by the ascent of the base).
    // For ease of implementation, 
    // this assumes that the font-designer designs accents 
    // in such a way that the bottom of the accent is atleast x-height
    // above its baseline, otherwise there will be collisions
    // with the base. Also there should be proper padding between
    // the bottom of the accent char and its baseline.
    // The above rule may not be obvious from a first
    // reading of rule 12 in the TeXBook !!!
    // The mathml <mover> tag can use accent chars that
    // do not follow this convention. So we modify TeX's rule 
    // so that TeX's rule gets subsumed for accents that follow 
    // TeX's convention,
    // while also allowing accents that do not follow the convention :
    // we try to keep the *bottom* of the accent char atleast x-height 
    // from the baseline of the base char. we also slap on an extra
    // padding between the accent and base chars.
    overDelta1 = ruleThickness + onePixel/2;
    nscoord accentBaseHeight = xHeight;
    if (mathFont) {
      accentBaseHeight =
        mathFont->GetMathConstant(gfxFontEntry::AccentBaseHeight,
                                  oneDevPixel);
    }
    if (bmBase.ascent < accentBaseHeight) {
      // also ensure at least accentBaseHeight above the baseline of the base
      overDelta1 += accentBaseHeight - bmBase.ascent;
    }
    overDelta2 = ruleThickness;
  }
  // empty over?
  if (!(bmOver.ascent + bmOver.descent)) {
    overDelta1 = 0;
    overDelta2 = 0;
  }

  nscoord dxBase = 0, dxOver = 0, dxUnder = 0;
  nsAutoString valueAlign;
  enum {
    center,
    left,
    right
  } alignPosition = center;

  if (mContent->GetAttr(kNameSpaceID_None, nsGkAtoms::align, valueAlign)) {
    if (valueAlign.EqualsLiteral("left")) {
      alignPosition = left;
    } else if (valueAlign.EqualsLiteral("right")) {
      alignPosition = right;
    }
  }

  //////////
  // pass 1, do what <mover> does: attach the overscript on the base

  // Ad-hoc - This is to override fonts which have ready-made _accent_
  // glyphs with negative lbearing and rbearing. We want to position
  // the overscript ourselves
  nscoord overWidth = bmOver.width;
  if (!overWidth && (bmOver.rightBearing - bmOver.leftBearing > 0)) {
    overWidth = bmOver.rightBearing - bmOver.leftBearing;
    dxOver = -bmOver.leftBearing;
  }

  if (NS_MATHML_EMBELLISH_IS_ACCENTOVER(mEmbellishData.flags)) {
    mBoundingMetrics.width = bmBase.width; 
    if (alignPosition == center) {
      dxOver += correction;
    }
  }
  else {
    mBoundingMetrics.width = std::max(bmBase.width, overWidth);
    if (alignPosition == center) {
      dxOver += correction/2;
    }
  }
  
  if (alignPosition == center) {
    dxOver += (mBoundingMetrics.width - overWidth)/2;
    dxBase = (mBoundingMetrics.width - bmBase.width)/2;
  } else if (alignPosition == right) {
    dxOver += mBoundingMetrics.width - overWidth;
    dxBase = mBoundingMetrics.width - bmBase.width;
  }

  mBoundingMetrics.ascent = 
    bmBase.ascent + overDelta1 + bmOver.ascent + bmOver.descent;
  mBoundingMetrics.descent = bmBase.descent;
  mBoundingMetrics.leftBearing = 
    std::min(dxBase + bmBase.leftBearing, dxOver + bmOver.leftBearing);
  mBoundingMetrics.rightBearing = 
    std::max(dxBase + bmBase.rightBearing, dxOver + bmOver.rightBearing);

  //////////
  // pass 2, do what <munder> does: attach the underscript on the previous
  // result. We conceptually view the previous result as an "anynomous base" 
  // from where to attach the underscript. Hence if the underscript is empty,
  // we should end up like <mover>. If the overscript is empty, we should
  // end up like <munder>.

  nsBoundingMetrics bmAnonymousBase = mBoundingMetrics;
  nscoord ascentAnonymousBase =
    std::max(mBoundingMetrics.ascent + overDelta2,
             overSize.BlockStartAscent() + bmOver.descent +
             overDelta1 + bmBase.ascent);
  ascentAnonymousBase = std::max(ascentAnonymousBase,
                                 baseSize.BlockStartAscent());

  // Width of non-spacing marks is zero so use left and right bearing.
  nscoord underWidth = bmUnder.width;
  if (!underWidth) {
    underWidth = bmUnder.rightBearing - bmUnder.leftBearing;
    dxUnder = -bmUnder.leftBearing;
  }

  nscoord maxWidth = std::max(bmAnonymousBase.width, underWidth);
  if (alignPosition == center &&
      !NS_MATHML_EMBELLISH_IS_ACCENTUNDER(mEmbellishData.flags)) {
    GetItalicCorrection(bmAnonymousBase, correction);
    dxUnder += -correction/2;
  }
  nscoord dxAnonymousBase = 0;
  if (alignPosition == center) {
    dxUnder += (maxWidth - underWidth)/2;
    dxAnonymousBase = (maxWidth - bmAnonymousBase.width)/2;
  } else if (alignPosition == right) {
    dxUnder += maxWidth - underWidth;
    dxAnonymousBase = maxWidth - bmAnonymousBase.width;
  }

  // adjust the offsets of the real base and overscript since their
  // final offsets should be relative to us...
  dxOver += dxAnonymousBase;
  dxBase += dxAnonymousBase;

  mBoundingMetrics.width =
    std::max(dxAnonymousBase + bmAnonymousBase.width, dxUnder + bmUnder.width);
  // At this point, mBoundingMetrics.ascent = bmAnonymousBase.ascent 
  mBoundingMetrics.descent = 
    bmAnonymousBase.descent + underDelta1 + bmUnder.ascent + bmUnder.descent;
  mBoundingMetrics.leftBearing =
    std::min(dxAnonymousBase + bmAnonymousBase.leftBearing, dxUnder + bmUnder.leftBearing);
  mBoundingMetrics.rightBearing = 
    std::max(dxAnonymousBase + bmAnonymousBase.rightBearing, dxUnder + bmUnder.rightBearing);

  aDesiredSize.SetBlockStartAscent(ascentAnonymousBase);
  aDesiredSize.Height() = aDesiredSize.BlockStartAscent() +
    std::max(mBoundingMetrics.descent + underDelta2,
           bmAnonymousBase.descent + underDelta1 + bmUnder.ascent +
             underSize.Height() - underSize.BlockStartAscent());
  aDesiredSize.Height() = std::max(aDesiredSize.Height(),
                               aDesiredSize.BlockStartAscent() +
                               baseSize.Height() - baseSize.BlockStartAscent());
  aDesiredSize.Width() = mBoundingMetrics.width;
  aDesiredSize.mBoundingMetrics = mBoundingMetrics;

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

  if (aPlaceOrigin) {
    nscoord dy;
    // place overscript
    if (overFrame) {
      dy = aDesiredSize.BlockStartAscent() -
           mBoundingMetrics.ascent + bmOver.ascent -
           overSize.BlockStartAscent();
      FinishReflowChild (overFrame, PresContext(), overSize, nullptr, dxOver, dy, 0);
    }
    // place base
    dy = aDesiredSize.BlockStartAscent() - baseSize.BlockStartAscent();
    FinishReflowChild (baseFrame, PresContext(), baseSize, nullptr, dxBase, dy, 0);
    // place underscript
    if (underFrame) {
      dy = aDesiredSize.BlockStartAscent() +
           mBoundingMetrics.descent - bmUnder.descent -
           underSize.BlockStartAscent();
      FinishReflowChild (underFrame, PresContext(), underSize, nullptr,
                         dxUnder, dy, 0);
    }
  }
  return NS_OK;
}
Exemplo n.º 11
0
void
nsSVGOuterSVGFrame::Reflow(nsPresContext*           aPresContext,
                           ReflowOutput&     aDesiredSize,
                           const ReflowInput& aReflowInput,
                           nsReflowStatus&          aStatus)
{
  MarkInReflow();
  DO_GLOBAL_REFLOW_COUNT("nsSVGOuterSVGFrame");
  DISPLAY_REFLOW(aPresContext, this, aReflowInput, aDesiredSize, aStatus);
  NS_FRAME_TRACE(NS_FRAME_TRACE_CALLS,
                  ("enter nsSVGOuterSVGFrame::Reflow: availSize=%d,%d",
                  aReflowInput.AvailableWidth(), aReflowInput.AvailableHeight()));

  NS_PRECONDITION(mState & NS_FRAME_IN_REFLOW, "frame is not in reflow");

  aStatus = NS_FRAME_COMPLETE;

  aDesiredSize.Width()  = aReflowInput.ComputedWidth() +
                          aReflowInput.ComputedPhysicalBorderPadding().LeftRight();
  aDesiredSize.Height() = aReflowInput.ComputedHeight() +
                          aReflowInput.ComputedPhysicalBorderPadding().TopBottom();

  NS_ASSERTION(!GetPrevInFlow(), "SVG can't currently be broken across pages.");

  SVGSVGElement *svgElem = static_cast<SVGSVGElement*>(mContent);

  nsSVGOuterSVGAnonChildFrame *anonKid =
    static_cast<nsSVGOuterSVGAnonChildFrame*>(PrincipalChildList().FirstChild());

  if (mState & NS_FRAME_FIRST_REFLOW) {
    // Initialize
    svgElem->UpdateHasChildrenOnlyTransform();
  }

  // If our SVG viewport has changed, update our content and notify.
  // http://www.w3.org/TR/SVG11/coords.html#ViewportSpace

  svgFloatSize newViewportSize(
    nsPresContext::AppUnitsToFloatCSSPixels(aReflowInput.ComputedWidth()),
    nsPresContext::AppUnitsToFloatCSSPixels(aReflowInput.ComputedHeight()));

  svgFloatSize oldViewportSize = svgElem->GetViewportSize();

  uint32_t changeBits = 0;
  if (newViewportSize != oldViewportSize) {
    // When our viewport size changes, we may need to update the overflow rects
    // of our child frames. This is the case if:
    //
    //  * We have a real/synthetic viewBox (a children-only transform), since
    //    the viewBox transform will change as the viewport dimensions change.
    //
    //  * We do not have a real/synthetic viewBox, but the last time we
    //    reflowed (or the last time UpdateOverflow() was called) we did.
    //
    // We only handle the former case here, in which case we mark all our child
    // frames as dirty so that we reflow them below and update their overflow
    // rects.
    //
    // In the latter case, updating of overflow rects is handled for removal of
    // real viewBox (the viewBox attribute) in AttributeChanged. Synthetic
    // viewBox "removal" (e.g. a document references the same SVG via both an
    // <svg:image> and then as a CSS background image (a synthetic viewBox is
    // used when painting the former, but not when painting the latter)) is
    // handled in SVGSVGElement::FlushImageTransformInvalidation.
    //
    if (svgElem->HasViewBoxOrSyntheticViewBox()) {
      nsIFrame* anonChild = PrincipalChildList().FirstChild();
      anonChild->AddStateBits(NS_FRAME_IS_DIRTY);
      for (nsIFrame* child : anonChild->PrincipalChildList()) {
        child->AddStateBits(NS_FRAME_IS_DIRTY);
      }
    }
    changeBits |= COORD_CONTEXT_CHANGED;
    svgElem->SetViewportSize(newViewportSize);
  }
  if (mFullZoom != PresContext()->GetFullZoom()) {
    changeBits |= FULL_ZOOM_CHANGED;
    mFullZoom = PresContext()->GetFullZoom();
  }
  if (changeBits) {
    NotifyViewportOrTransformChanged(changeBits);
  }
  mViewportInitialized = true;

  // Now that we've marked the necessary children as dirty, call
  // ReflowSVG() or ReflowSVGNonDisplayText() on them, depending
  // on whether we are non-display.
  mCallingReflowSVG = true;
  if (GetStateBits() & NS_FRAME_IS_NONDISPLAY) {
    ReflowSVGNonDisplayText(this);
  } else {
    // Update the mRects and visual overflow rects of all our descendants,
    // including our anonymous wrapper kid:
    anonKid->AddStateBits(mState & NS_FRAME_IS_DIRTY);
    anonKid->ReflowSVG();
    MOZ_ASSERT(!anonKid->GetNextSibling(),
               "We should have one anonymous child frame wrapping our real "
               "children");
  }
  mCallingReflowSVG = false;

  // Set our anonymous kid's offset from our border box:
  anonKid->SetPosition(GetContentRectRelativeToSelf().TopLeft());

  // Including our size in our overflow rects regardless of the value of
  // 'background', 'border', etc. makes sure that we usually (when we clip to
  // our content area) don't have to keep changing our overflow rects as our
  // descendants move about (see perf comment below). Including our size in our
  // scrollable overflow rect also makes sure that we scroll if we're too big
  // for our viewport.
  //
  // <svg> never allows scrolling to anything outside its mRect (only panning),
  // so we must always keep our scrollable overflow set to our size.
  //
  // With regards to visual overflow, we always clip root-<svg> (see our
  // BuildDisplayList method) regardless of the value of the 'overflow'
  // property since that is per-spec, even for the initial 'visible' value. For
  // that reason there's no point in adding descendant visual overflow to our
  // own when this frame is for a root-<svg>. That said, there's also a very
  // good performance reason for us wanting to avoid doing so. If we did, then
  // the frame's overflow would often change as descendants that are partially
  // or fully outside its rect moved (think animation on/off screen), and that
  // would cause us to do a full NS_FRAME_IS_DIRTY reflow and repaint of the
  // entire document tree each such move (see bug 875175).
  //
  // So it's only non-root outer-<svg> that has the visual overflow of its
  // descendants added to its own. (Note that the default user-agent style
  // sheet makes 'hidden' the default value for :not(root(svg)), so usually
  // FinishAndStoreOverflow will still clip this back to the frame's rect.)
  //
  // WARNING!! Keep UpdateBounds below in sync with whatever we do for our
  // overflow rects here! (Again, see bug 875175.)
  //
  aDesiredSize.SetOverflowAreasToDesiredBounds();
  if (!mIsRootContent) {
    aDesiredSize.mOverflowAreas.VisualOverflow().UnionRect(
      aDesiredSize.mOverflowAreas.VisualOverflow(),
      anonKid->GetVisualOverflowRect() + anonKid->GetPosition());
  }
  FinishAndStoreOverflow(&aDesiredSize);

  NS_FRAME_TRACE(NS_FRAME_TRACE_CALLS,
                  ("exit nsSVGOuterSVGFrame::Reflow: size=%d,%d",
                  aDesiredSize.Width(), aDesiredSize.Height()));
  NS_FRAME_SET_TRUNCATION(aStatus, aReflowInput, aDesiredSize);
}
Exemplo n.º 12
0
void
nsVideoFrame::Reflow(nsPresContext* aPresContext,
                     ReflowOutput& aMetrics,
                     const ReflowInput& aReflowInput,
                     nsReflowStatus& aStatus)
{
  MarkInReflow();
  DO_GLOBAL_REFLOW_COUNT("nsVideoFrame");
  DISPLAY_REFLOW(aPresContext, this, aReflowInput, aMetrics, aStatus);
  NS_FRAME_TRACE(NS_FRAME_TRACE_CALLS,
                 ("enter nsVideoFrame::Reflow: availSize=%d,%d",
                  aReflowInput.AvailableWidth(),
                  aReflowInput.AvailableHeight()));

  NS_PRECONDITION(mState & NS_FRAME_IN_REFLOW, "frame is not in reflow");

  aStatus = NS_FRAME_COMPLETE;

  const WritingMode myWM = aReflowInput.GetWritingMode();
  nscoord contentBoxBSize = aReflowInput.ComputedBSize();
  const nscoord borderBoxISize = aReflowInput.ComputedISize() +
    aReflowInput.ComputedLogicalBorderPadding().IStartEnd(myWM);
  const bool isBSizeShrinkWrapping = (contentBoxBSize == NS_INTRINSICSIZE);

  nscoord borderBoxBSize;
  if (!isBSizeShrinkWrapping) {
    borderBoxBSize = contentBoxBSize +
      aReflowInput.ComputedLogicalBorderPadding().BStartEnd(myWM);
  }

  nsMargin borderPadding = aReflowInput.ComputedPhysicalBorderPadding();

  // Reflow the child frames. We may have up to three: an image
  // frame (for the poster image), a container frame for the controls,
  // and a container frame for the caption.
  for (nsIFrame* child : mFrames) {
    nsSize oldChildSize = child->GetSize();

    if (child->GetContent() == mPosterImage) {
      // Reflow the poster frame.
      nsImageFrame* imageFrame = static_cast<nsImageFrame*>(child);
      ReflowOutput kidDesiredSize(aReflowInput);
      WritingMode wm = imageFrame->GetWritingMode();
      LogicalSize availableSize = aReflowInput.AvailableSize(wm);
      LogicalSize cbSize = aMetrics.Size(aMetrics.GetWritingMode()).
                             ConvertTo(wm, aMetrics.GetWritingMode());
      ReflowInput kidReflowInput(aPresContext,
                                       aReflowInput,
                                       imageFrame,
                                       availableSize,
                                       &cbSize);

      nsRect posterRenderRect;
      if (ShouldDisplayPoster()) {
        posterRenderRect =
          nsRect(nsPoint(borderPadding.left, borderPadding.top),
                 nsSize(aReflowInput.ComputedWidth(),
                        aReflowInput.ComputedHeight()));
      }
      kidReflowInput.SetComputedWidth(posterRenderRect.width);
      kidReflowInput.SetComputedHeight(posterRenderRect.height);
      ReflowChild(imageFrame, aPresContext, kidDesiredSize, kidReflowInput,
                  posterRenderRect.x, posterRenderRect.y, 0, aStatus);
      FinishReflowChild(imageFrame, aPresContext,
                        kidDesiredSize, &kidReflowInput,
                        posterRenderRect.x, posterRenderRect.y, 0);

// Android still uses XUL media controls & hence needs this XUL-friendly
// custom reflow code. This will go away in bug 1310907.
#ifdef ANDROID
    } else if (child->GetContent() == mVideoControls) {
      // Reflow the video controls frame.
      nsBoxLayoutState boxState(PresContext(), aReflowInput.mRenderingContext);
      nsBoxFrame::LayoutChildAt(boxState,
                                child,
                                nsRect(borderPadding.left,
                                       borderPadding.top,
                                       aReflowInput.ComputedWidth(),
                                       aReflowInput.ComputedHeight()));

#endif // ANDROID
    } else if (child->GetContent() == mCaptionDiv ||
               child->GetContent() == mVideoControls) {
      // Reflow the caption and control bar frames.
      WritingMode wm = child->GetWritingMode();
      LogicalSize availableSize = aReflowInput.ComputedSize(wm);
      availableSize.BSize(wm) = NS_UNCONSTRAINEDSIZE;

      ReflowInput kidReflowInput(aPresContext,
                                       aReflowInput,
                                       child,
                                       availableSize);
      ReflowOutput kidDesiredSize(kidReflowInput);
      ReflowChild(child, aPresContext, kidDesiredSize, kidReflowInput,
                  borderPadding.left, borderPadding.top, 0, aStatus);

      if (child->GetContent() == mVideoControls && isBSizeShrinkWrapping) {
        // Resolve our own BSize based on the controls' size in the same axis.
        contentBoxBSize = myWM.IsOrthogonalTo(wm) ?
          kidDesiredSize.ISize(wm) : kidDesiredSize.BSize(wm);
      }

      FinishReflowChild(child, aPresContext,
                        kidDesiredSize, &kidReflowInput,
                        borderPadding.left, borderPadding.top, 0);
    }

    if (child->GetContent() == mVideoControls && child->GetSize() != oldChildSize) {
      RefPtr<Runnable> event = new DispatchResizeToControls(child->GetContent());
      nsContentUtils::AddScriptRunner(event);
    }
  }

  if (isBSizeShrinkWrapping) {
    if (contentBoxBSize == NS_INTRINSICSIZE) {
      // We didn't get a BSize from our intrinsic size/ratio, nor did we
      // get one from our controls. Just use BSize of 0.
      contentBoxBSize = 0;
    }
    contentBoxBSize = NS_CSS_MINMAX(contentBoxBSize,
                                    aReflowInput.ComputedMinBSize(),
                                    aReflowInput.ComputedMaxBSize());
    borderBoxBSize = contentBoxBSize +
      aReflowInput.ComputedLogicalBorderPadding().BStartEnd(myWM);
  }

  LogicalSize logicalDesiredSize(myWM, borderBoxISize, borderBoxBSize);
  aMetrics.SetSize(myWM, logicalDesiredSize);

  aMetrics.SetOverflowAreasToDesiredBounds();

  FinishAndStoreOverflow(&aMetrics);

  NS_FRAME_TRACE(NS_FRAME_TRACE_CALLS,
                 ("exit nsVideoFrame::Reflow: size=%d,%d",
                  aMetrics.Width(), aMetrics.Height()));
  NS_FRAME_SET_TRUNCATION(aStatus, aReflowInput, aMetrics);
}
Exemplo n.º 13
0
nsresult
nsMathMLmfracFrame::PlaceInternal(DrawTarget*          aDrawTarget,
                                  bool                 aPlaceOrigin,
                                  ReflowOutput& aDesiredSize,
                                  bool                 aWidthOnly)
{
  ////////////////////////////////////
  // Get the children's desired sizes
  nsBoundingMetrics bmNum, bmDen;
  ReflowOutput sizeNum(aDesiredSize.GetWritingMode());
  ReflowOutput sizeDen(aDesiredSize.GetWritingMode());
  nsIFrame* frameDen = nullptr;
  nsIFrame* frameNum = mFrames.FirstChild();
  if (frameNum) 
    frameDen = frameNum->GetNextSibling();
  if (!frameNum || !frameDen || frameDen->GetNextSibling()) {
    // report an error, encourage people to get their markups in order
    if (aPlaceOrigin) {
      ReportChildCountError();
    }
    return ReflowError(aDrawTarget, aDesiredSize);
  }
  GetReflowAndBoundingMetricsFor(frameNum, sizeNum, bmNum);
  GetReflowAndBoundingMetricsFor(frameDen, sizeDen, bmDen);

  nsPresContext* presContext = PresContext();
  nscoord onePixel = nsPresContext::CSSPixelsToAppUnits(1);

  float fontSizeInflation = nsLayoutUtils::FontSizeInflationFor(this);
  RefPtr<nsFontMetrics> fm =
    nsLayoutUtils::GetFontMetricsForFrame(this, fontSizeInflation);

  nscoord defaultRuleThickness, axisHeight;
  nscoord oneDevPixel = fm->AppUnitsPerDevPixel();
  gfxFont* mathFont = fm->GetThebesFontGroup()->GetFirstMathFont();
  if (mathFont) {
    defaultRuleThickness =
      mathFont->GetMathConstant(gfxFontEntry::FractionRuleThickness,
                                oneDevPixel);
  } else {
    GetRuleThickness(aDrawTarget, fm, defaultRuleThickness);
  }
  GetAxisHeight(aDrawTarget, fm, axisHeight);

  bool outermostEmbellished = false;
  if (mEmbellishData.coreFrame) {
    nsEmbellishData parentData;
    GetEmbellishDataFrom(GetParent(), parentData);
    outermostEmbellished = parentData.coreFrame != mEmbellishData.coreFrame;
  }

  // see if the linethickness attribute is there 
  nsAutoString value;
  mContent->GetAttr(kNameSpaceID_None, nsGkAtoms::linethickness_, value);
  mLineThickness = CalcLineThickness(presContext, mStyleContext, value,
                                     onePixel, defaultRuleThickness,
                                     fontSizeInflation);

  // bevelled attribute
  mContent->GetAttr(kNameSpaceID_None, nsGkAtoms::bevelled_, value);
  mIsBevelled = value.EqualsLiteral("true");

  bool displayStyle = StyleFont()->mMathDisplay == NS_MATHML_DISPLAYSTYLE_BLOCK;

  if (!mIsBevelled) {
    mLineRect.height = mLineThickness;

    // by default, leave at least one-pixel padding at either end, and add
    // lspace & rspace that may come from <mo> if we are an outermost
    // embellished container (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)
    nscoord leftSpace = onePixel;
    nscoord rightSpace = onePixel;
    if (outermostEmbellished) {
      nsEmbellishData coreData;
      GetEmbellishDataFrom(mEmbellishData.coreFrame, coreData);
      leftSpace += StyleVisibility()->mDirection ?
                     coreData.trailingSpace : coreData.leadingSpace;
      rightSpace += StyleVisibility()->mDirection ?
                      coreData.leadingSpace : coreData.trailingSpace;
    }

    nscoord actualRuleThickness =  mLineThickness;

    //////////////////
    // Get shifts
    nscoord numShift = 0;
    nscoord denShift = 0;

    // Rule 15b, App. G, TeXbook
    nscoord numShift1, numShift2, numShift3;
    nscoord denShift1, denShift2;

    GetNumeratorShifts(fm, numShift1, numShift2, numShift3);
    GetDenominatorShifts(fm, denShift1, denShift2);

    if (0 == actualRuleThickness) {
      numShift = displayStyle ? numShift1 : numShift3;
      denShift = displayStyle ? denShift1 : denShift2;
      if (mathFont) {
        numShift = mathFont->
          GetMathConstant(displayStyle ?
                          gfxFontEntry::StackTopDisplayStyleShiftUp :
                          gfxFontEntry::StackTopShiftUp,
                          oneDevPixel);
        denShift = mathFont->
          GetMathConstant(displayStyle ?
                          gfxFontEntry::StackBottomDisplayStyleShiftDown :
                          gfxFontEntry::StackBottomShiftDown,
                          oneDevPixel);
      }
    } else {
      numShift = displayStyle ? numShift1 : numShift2;
      denShift = displayStyle ? denShift1 : denShift2;
      if (mathFont) {
        numShift = mathFont->
          GetMathConstant(displayStyle ?
                          gfxFontEntry::FractionNumeratorDisplayStyleShiftUp :
                          gfxFontEntry::FractionNumeratorShiftUp,
                          oneDevPixel);
        denShift = mathFont->
          GetMathConstant(
            displayStyle ?
            gfxFontEntry::FractionDenominatorDisplayStyleShiftDown :
            gfxFontEntry::FractionDenominatorShiftDown,
            oneDevPixel);
      }
    }

    if (0 == actualRuleThickness) {
      // Rule 15c, App. G, TeXbook

      // min clearance between numerator and denominator
      nscoord minClearance = displayStyle ?
        7 * defaultRuleThickness : 3 * defaultRuleThickness;
      if (mathFont) {
        minClearance =
          mathFont->GetMathConstant(displayStyle ?
                                    gfxFontEntry::StackDisplayStyleGapMin :
                                    gfxFontEntry::StackGapMin,
                                    oneDevPixel);
      }
      // Factor in axis height
      // http://www.mathml-association.org/MathMLinHTML5/S3.html#SS3.SSS2
      numShift += axisHeight;
      denShift += axisHeight;

      nscoord actualClearance =
        (numShift - bmNum.descent) - (bmDen.ascent - denShift);
      // actualClearance should be >= minClearance
      if (actualClearance < minClearance) {
        nscoord halfGap = (minClearance - actualClearance)/2;
        numShift += halfGap;
        denShift += halfGap;
      }
    }
    else {
    // Rule 15d, App. G, TeXbook

    // min clearance between numerator or denominator and middle of bar

    // TeX has a different interpretation of the thickness.
    // Try $a \above10pt b$ to see. Here is what TeX does:
    // minClearance = displayStyle ?
    //   3 * actualRuleThickness : actualRuleThickness;
 
    // we slightly depart from TeX here. We use the defaultRuleThickness instead
    // of the value coming from the linethickness attribute, i.e., we recover what
    // TeX does if the user hasn't set linethickness. But when the linethickness
    // is set, we avoid the wide gap problem.
      nscoord minClearanceNum = displayStyle ?
        3 * defaultRuleThickness : defaultRuleThickness + onePixel;
      nscoord minClearanceDen = minClearanceNum;
      if (mathFont) {
        minClearanceNum = mathFont->
          GetMathConstant(displayStyle ?
                          gfxFontEntry::FractionNumDisplayStyleGapMin :
                          gfxFontEntry::FractionNumeratorGapMin,
                          oneDevPixel);
        minClearanceDen = mathFont->
          GetMathConstant(displayStyle ?
                          gfxFontEntry::FractionDenomDisplayStyleGapMin :
                          gfxFontEntry::FractionDenominatorGapMin,
                          oneDevPixel);
      }

      // adjust numShift to maintain minClearanceNum if needed
      nscoord actualClearanceNum =
        (numShift - bmNum.descent) - (axisHeight + actualRuleThickness/2);
      if (actualClearanceNum < minClearanceNum) {
        numShift += (minClearanceNum - actualClearanceNum);
      }
      // adjust denShift to maintain minClearanceDen if needed
      nscoord actualClearanceDen =
        (axisHeight - actualRuleThickness/2) - (bmDen.ascent - denShift);
      if (actualClearanceDen < minClearanceDen) {
        denShift += (minClearanceDen - actualClearanceDen);
      }
    }

    //////////////////
    // Place Children

    // XXX Need revisiting the width. TeX uses the exact width
    // e.g. in $$\huge\frac{\displaystyle\int}{i}$$
    nscoord width = std::max(bmNum.width, bmDen.width);
    nscoord dxNum = leftSpace + (width - sizeNum.Width())/2;
    nscoord dxDen = leftSpace + (width - sizeDen.Width())/2;
    width += leftSpace + rightSpace;

    // see if the numalign attribute is there 
    mContent->GetAttr(kNameSpaceID_None, nsGkAtoms::numalign_, value);
    if (value.EqualsLiteral("left"))
      dxNum = leftSpace;
    else if (value.EqualsLiteral("right"))
      dxNum = width - rightSpace - sizeNum.Width();

    // see if the denomalign attribute is there 
    mContent->GetAttr(kNameSpaceID_None, nsGkAtoms::denomalign_, value);
    if (value.EqualsLiteral("left"))
      dxDen = leftSpace;
    else if (value.EqualsLiteral("right"))
      dxDen = width - rightSpace - sizeDen.Width();

    mBoundingMetrics.rightBearing =
      std::max(dxNum + bmNum.rightBearing, dxDen + bmDen.rightBearing);
    if (mBoundingMetrics.rightBearing < width - rightSpace)
      mBoundingMetrics.rightBearing = width - rightSpace;
    mBoundingMetrics.leftBearing =
      std::min(dxNum + bmNum.leftBearing, dxDen + bmDen.leftBearing);
    if (mBoundingMetrics.leftBearing > leftSpace)
      mBoundingMetrics.leftBearing = leftSpace;
    mBoundingMetrics.ascent = bmNum.ascent + numShift;
    mBoundingMetrics.descent = bmDen.descent + denShift;
    mBoundingMetrics.width = width;

    aDesiredSize.SetBlockStartAscent(sizeNum.BlockStartAscent() + numShift);
    aDesiredSize.Height() = aDesiredSize.BlockStartAscent() +
      sizeDen.Height() - sizeDen.BlockStartAscent() + denShift;
    aDesiredSize.Width() = mBoundingMetrics.width;
    aDesiredSize.mBoundingMetrics = mBoundingMetrics;

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

    if (aPlaceOrigin) {
      nscoord dy;
      // place numerator
      dy = 0;
      FinishReflowChild(frameNum, presContext, sizeNum, nullptr, dxNum, dy, 0);
      // place denominator
      dy = aDesiredSize.Height() - sizeDen.Height();
      FinishReflowChild(frameDen, presContext, sizeDen, nullptr, dxDen, dy, 0);
      // place the fraction bar - dy is top of bar
      dy = aDesiredSize.BlockStartAscent() - (axisHeight + actualRuleThickness/2);
      mLineRect.SetRect(leftSpace, dy, width - (leftSpace + rightSpace),
                        actualRuleThickness);
    }
  } else {
    nscoord numShift = 0.0;
    nscoord denShift = 0.0;
    nscoord padding = 3 * defaultRuleThickness;
    nscoord slashRatio = 3;

    // Define the constant used in the expression of the maximum width
    nscoord em = fm->EmHeight();
    nscoord slashMaxWidthConstant = 2 * em;

    // For large line thicknesses the minimum slash height is limited to the
    // largest expected height of a fraction
    nscoord slashMinHeight = slashRatio *
      std::min(2 * mLineThickness, slashMaxWidthConstant);

    nscoord leadingSpace = padding;
    nscoord trailingSpace = padding;
    if (outermostEmbellished) {
      nsEmbellishData coreData;
      GetEmbellishDataFrom(mEmbellishData.coreFrame, coreData);
      leadingSpace += coreData.leadingSpace;
      trailingSpace += coreData.trailingSpace;
    }
    nscoord delta;
    
    //           ___________
    //          |           |    /
    //         {|-NUMERATOR-|   /
    //         {|___________|  S
    //         {               L
    // numShift{               A
    // ------------------------------------------------------- baseline
    //                         S   _____________ } denShift
    //                         H  |             |}
    //                        /   |-DENOMINATOR-|}
    //                       /    |_____________| 
    //

    // first, ensure that the top of the numerator is at least as high as the
    // top of the denominator (and the reverse for the bottoms)
    delta = std::max(bmDen.ascent - bmNum.ascent,
                   bmNum.descent - bmDen.descent) / 2;
    if (delta > 0) {
      numShift += delta;
      denShift += delta;
    }

    if (StyleFont()->mMathDisplay == NS_MATHML_DISPLAYSTYLE_BLOCK) {
      delta = std::min(bmDen.ascent + bmDen.descent,
                     bmNum.ascent + bmNum.descent) / 2;
      numShift += delta;
      denShift += delta;
    } else {
      nscoord xHeight = fm->XHeight();
      numShift += xHeight / 2;
      denShift += xHeight / 4;
    }
   
    // Set the ascent/descent of our BoundingMetrics.
    mBoundingMetrics.ascent = bmNum.ascent + numShift;
    mBoundingMetrics.descent = bmDen.descent + denShift;

    // At this point the height of the slash is
    // mBoundingMetrics.ascent + mBoundingMetrics.descent
    // Ensure that it is greater than slashMinHeight
    delta = (slashMinHeight -
             (mBoundingMetrics.ascent + mBoundingMetrics.descent)) / 2;
    if (delta > 0) {
      mBoundingMetrics.ascent += delta;
      mBoundingMetrics.descent += delta;
    }

    // Set the width of the slash
    if (aWidthOnly) {
      mLineRect.width = mLineThickness + slashMaxWidthConstant;
    } else {
      mLineRect.width = mLineThickness +
        std::min(slashMaxWidthConstant,
               (mBoundingMetrics.ascent + mBoundingMetrics.descent) /
               slashRatio);
    }

    // Set horizontal bounding metrics
    if (StyleVisibility()->mDirection) {
      mBoundingMetrics.leftBearing = trailingSpace + bmDen.leftBearing;
      mBoundingMetrics.rightBearing = trailingSpace + bmDen.width + mLineRect.width + bmNum.rightBearing;
    } else {
      mBoundingMetrics.leftBearing = leadingSpace + bmNum.leftBearing;
      mBoundingMetrics.rightBearing = leadingSpace + bmNum.width + mLineRect.width + bmDen.rightBearing;
    }
    mBoundingMetrics.width =
      leadingSpace + bmNum.width + mLineRect.width + bmDen.width +
      trailingSpace;

    // Set aDesiredSize
    aDesiredSize.SetBlockStartAscent(mBoundingMetrics.ascent + padding);
    aDesiredSize.Height() =
      mBoundingMetrics.ascent + mBoundingMetrics.descent + 2 * padding;
    aDesiredSize.Width() = mBoundingMetrics.width;
    aDesiredSize.mBoundingMetrics = mBoundingMetrics;

    mReference.x = 0;
    mReference.y = aDesiredSize.BlockStartAscent();
    
    if (aPlaceOrigin) {
      nscoord dx, dy;

      // place numerator
      dx = MirrorIfRTL(aDesiredSize.Width(), sizeNum.Width(),
                       leadingSpace);
      dy = aDesiredSize.BlockStartAscent() - numShift - sizeNum.BlockStartAscent();
      FinishReflowChild(frameNum, presContext, sizeNum, nullptr, dx, dy, 0);

      // place the fraction bar
      dx = MirrorIfRTL(aDesiredSize.Width(), mLineRect.width,
                       leadingSpace + bmNum.width);
      dy = aDesiredSize.BlockStartAscent() - mBoundingMetrics.ascent;
      mLineRect.SetRect(dx, dy,
                        mLineRect.width, aDesiredSize.Height() - 2 * padding);

      // place denominator
      dx = MirrorIfRTL(aDesiredSize.Width(), sizeDen.Width(),
                       leadingSpace + bmNum.width + mLineRect.width);
      dy = aDesiredSize.BlockStartAscent() + denShift - sizeDen.BlockStartAscent();
      FinishReflowChild(frameDen, presContext, sizeDen, nullptr, dx, dy, 0);
    }

  }

  return NS_OK;
}