C++ nsHTMLReflowState::ComputedSize方法代码示例

// Return the inline-size that the float (including margins) will take up
// in the writing mode of the containing block. If this returns
// NS_UNCONSTRAINEDSIZE, we're dealing with an orthogonal block that
// has block-size:auto, and we'll need to actually reflow it to find out
// how much inline-size it will occupy in the containing block's mode.
static nscoord
FloatMarginISize(const nsHTMLReflowState& aCBReflowState,
                 nscoord aFloatAvailableISize,
                 nsIFrame *aFloat,
                 const nsCSSOffsetState& aFloatOffsetState)
{
  AutoMaybeDisableFontInflation an(aFloat);
  WritingMode wm = aFloatOffsetState.GetWritingMode();

  LogicalSize floatSize =
    aFloat->ComputeSize(
              aCBReflowState.rendContext,
              wm,
              aCBReflowState.ComputedSize(wm),
              aFloatAvailableISize,
              aFloatOffsetState.ComputedLogicalMargin().Size(wm),
              aFloatOffsetState.ComputedLogicalBorderPadding().Size(wm) -
                aFloatOffsetState.ComputedLogicalPadding().Size(wm),
              aFloatOffsetState.ComputedLogicalPadding().Size(wm),
              nsIFrame::ComputeSizeFlags::eShrinkWrap);

  WritingMode cbwm = aCBReflowState.GetWritingMode();
  nscoord floatISize = floatSize.ConvertTo(cbwm, wm).ISize(cbwm);
  if (floatISize == NS_UNCONSTRAINEDSIZE) {
    return NS_UNCONSTRAINEDSIZE; // reflow is needed to get the true size
  }

  return floatISize +
         aFloatOffsetState.ComputedLogicalMargin().Size(wm).
           ConvertTo(cbwm, wm).ISize(cbwm) +
         aFloatOffsetState.ComputedLogicalBorderPadding().Size(wm).
           ConvertTo(cbwm, wm).ISize(cbwm);
}

void
nsMeterFrame::ReflowBarFrame(nsIFrame*                aBarFrame,
                             nsPresContext*           aPresContext,
                             const nsHTMLReflowState& aReflowState,
                             nsReflowStatus&          aStatus)
{
  bool vertical = ResolvedOrientationIsVertical();
  WritingMode wm = aBarFrame->GetWritingMode();
  LogicalSize availSize = aReflowState.ComputedSize(wm);
  availSize.BSize(wm) = NS_UNCONSTRAINEDSIZE;
  nsHTMLReflowState reflowState(aPresContext, aReflowState,
                                aBarFrame, availSize);
  nscoord size = vertical ? aReflowState.ComputedHeight()
                          : aReflowState.ComputedWidth();
  nscoord xoffset = aReflowState.ComputedPhysicalBorderPadding().left;
  nscoord yoffset = aReflowState.ComputedPhysicalBorderPadding().top;

  // NOTE: Introduce a new function getPosition in the content part ?
  HTMLMeterElement* meterElement = static_cast<HTMLMeterElement*>(mContent);

  double max = meterElement->Max();
  double min = meterElement->Min();
  double value = meterElement->Value();

  double position = max - min;
  position = position != 0 ? (value - min) / position : 1;

  size = NSToCoordRound(size * position);

  if (!vertical && (wm.IsVertical() ? wm.IsVerticalRL() : !wm.IsBidiLTR())) {
    xoffset += aReflowState.ComputedWidth() - size;
  }

  // The bar position is *always* constrained.
  if (vertical) {
    // We want the bar to begin at the bottom.
    yoffset += aReflowState.ComputedHeight() - size;

    size -= reflowState.ComputedPhysicalMargin().TopBottom() +
            reflowState.ComputedPhysicalBorderPadding().TopBottom();
    size = std::max(size, 0);
    reflowState.SetComputedHeight(size);
  } else {
    size -= reflowState.ComputedPhysicalMargin().LeftRight() +
            reflowState.ComputedPhysicalBorderPadding().LeftRight();
    size = std::max(size, 0);
    reflowState.SetComputedWidth(size);
  }

  xoffset += reflowState.ComputedPhysicalMargin().left;
  yoffset += reflowState.ComputedPhysicalMargin().top;

  nsHTMLReflowMetrics barDesiredSize(reflowState);
  ReflowChild(aBarFrame, aPresContext, barDesiredSize, reflowState, xoffset,
              yoffset, 0, aStatus);
  FinishReflowChild(aBarFrame, aPresContext, barDesiredSize, &reflowState,
                    xoffset, yoffset, 0);
}

void
nsMathMLTokenFrame::Reflow(nsPresContext*          aPresContext,
                           nsHTMLReflowMetrics&     aDesiredSize,
                           const nsHTMLReflowState& aReflowState,
                           nsReflowStatus&          aStatus)
{
  MarkInReflow();
  mPresentationData.flags &= ~NS_MATHML_ERROR;

  // initializations needed for empty markup like <mtag></mtag>
  aDesiredSize.ClearSize();
  aDesiredSize.SetBlockStartAscent(0);
  aDesiredSize.mBoundingMetrics = nsBoundingMetrics();

  nsIFrame* childFrame = GetFirstPrincipalChild();
  while (childFrame) {
    // ask our children to compute their bounding metrics
    nsHTMLReflowMetrics childDesiredSize(aReflowState.GetWritingMode(),
                                         aDesiredSize.mFlags
                                         | NS_REFLOW_CALC_BOUNDING_METRICS);
    WritingMode wm = childFrame->GetWritingMode();
    LogicalSize availSize = aReflowState.ComputedSize(wm);
    availSize.BSize(wm) = NS_UNCONSTRAINEDSIZE;
    nsHTMLReflowState childReflowState(aPresContext, aReflowState,
                                       childFrame, availSize);
    ReflowChild(childFrame, aPresContext, childDesiredSize,
                childReflowState, aStatus);
    //NS_ASSERTION(NS_FRAME_IS_COMPLETE(aStatus), "bad status");
    SaveReflowAndBoundingMetricsFor(childFrame, childDesiredSize,
                                    childDesiredSize.mBoundingMetrics);

    childFrame = childFrame->GetNextSibling();
  }

  // place and size children
  FinalizeReflow(aReflowState.rendContext->GetDrawTarget(), aDesiredSize);

  aStatus = NS_FRAME_COMPLETE;
  NS_FRAME_SET_TRUNCATION(aStatus, aReflowState, aDesiredSize);
}

void
nsHTMLButtonControlFrame::ReflowButtonContents(nsPresContext* aPresContext,
                                               nsHTMLReflowMetrics& aButtonDesiredSize,
                                               const nsHTMLReflowState& aButtonReflowState,
                                               nsIFrame* aFirstKid)
{
  // Buttons have some bonus renderer-determined border/padding,
  // which occupies part of the button's content-box area:
  const nsMargin focusPadding = mRenderer.GetAddedButtonBorderAndPadding();

  WritingMode wm = aFirstKid->GetWritingMode();
  LogicalSize availSize = aButtonReflowState.ComputedSize(GetWritingMode());
  availSize.BSize(wm) = NS_INTRINSICSIZE;

  // Indent the child inside us by the focus border. We must do this separate
  // from the regular border.
  availSize.ISize(wm) -= LogicalMargin(wm, focusPadding).IStartEnd(wm);

  // See whether out availSize's width is big enough.  If it's smaller than our
  // intrinsic min width, that means that the kid wouldn't really fit; for a
  // better look in such cases we adjust the available width and our left
  // offset to allow the kid to spill left into our padding.
  nscoord xoffset = focusPadding.left +
    aButtonReflowState.ComputedPhysicalBorderPadding().left;
  nscoord extrawidth = GetMinISize(aButtonReflowState.rendContext) -
    aButtonReflowState.ComputedWidth();
  if (extrawidth > 0) {
    nscoord extraleft = extrawidth / 2;
    nscoord extraright = extrawidth - extraleft;
    NS_ASSERTION(extraright >=0, "How'd that happen?");

    // Do not allow the extras to be bigger than the relevant padding
    extraleft = std::min(extraleft, aButtonReflowState.ComputedPhysicalPadding().left);
    extraright = std::min(extraright, aButtonReflowState.ComputedPhysicalPadding().right);
    xoffset -= extraleft;
    availSize.Width(wm) = availSize.Width(wm) + extraleft + extraright;
  }
  availSize.Width(wm) = std::max(availSize.Width(wm), 0);

  // Give child a clone of the button's reflow state, with height/width reduced
  // by focusPadding, so that descendants with height:100% don't protrude.
  nsHTMLReflowState adjustedButtonReflowState =
    CloneReflowStateWithReducedContentBox(aButtonReflowState, focusPadding);

  nsHTMLReflowState contentsReflowState(aPresContext,
                                        adjustedButtonReflowState,
                                        aFirstKid, availSize);

  nsReflowStatus contentsReflowStatus;
  nsHTMLReflowMetrics contentsDesiredSize(aButtonReflowState);
  ReflowChild(aFirstKid, aPresContext,
              contentsDesiredSize, contentsReflowState,
              xoffset,
              focusPadding.top + aButtonReflowState.ComputedPhysicalBorderPadding().top,
              0, contentsReflowStatus);
  MOZ_ASSERT(NS_FRAME_IS_COMPLETE(contentsReflowStatus),
             "We gave button-contents frame unconstrained available height, "
             "so it should be complete");

  // Compute the button's content-box height:
  nscoord buttonContentBoxHeight = 0;
  if (aButtonReflowState.ComputedHeight() != NS_INTRINSICSIZE) {
    // Button has a fixed height -- that's its content-box height.
    buttonContentBoxHeight = aButtonReflowState.ComputedHeight();
  } else {
    // Button is intrinsically sized -- it should shrinkwrap the
    // button-contents' height, plus any focus-padding space:
    buttonContentBoxHeight =
      contentsDesiredSize.Height() + focusPadding.TopBottom();

    // Make sure we obey min/max-height in the case when we're doing intrinsic
    // sizing (we get it for free when we have a non-intrinsic
    // aButtonReflowState.ComputedHeight()).  Note that we do this before
    // adjusting for borderpadding, since mComputedMaxHeight and
    // mComputedMinHeight are content heights.
    buttonContentBoxHeight =
      NS_CSS_MINMAX(buttonContentBoxHeight,
                    aButtonReflowState.ComputedMinHeight(),
                    aButtonReflowState.ComputedMaxHeight());
  }

  // Center child vertically in the button
  // (technically, inside of the button's focus-padding area)
  nscoord extraSpace =
    buttonContentBoxHeight - focusPadding.TopBottom() -
    contentsDesiredSize.Height();

  nscoord yoffset = std::max(0, extraSpace / 2);

  // Adjust yoffset to be in terms of the button's frame-rect, instead of
  // its focus-padding rect:
  yoffset += focusPadding.top + aButtonReflowState.ComputedPhysicalBorderPadding().top;

  // Place the child
  FinishReflowChild(aFirstKid, aPresContext,
                    contentsDesiredSize, &contentsReflowState,
                    xoffset, yoffset, 0);

  // Make sure we have a useful 'ascent' value for the child
  if (contentsDesiredSize.BlockStartAscent() ==
//.........这里部分代码省略.........

void
nsMathMLmrootFrame::Reflow(nsPresContext*          aPresContext,
                           nsHTMLReflowMetrics&     aDesiredSize,
                           const nsHTMLReflowState& aReflowState,
                           nsReflowStatus&          aStatus)
{
  MarkInReflow();
  nsReflowStatus childStatus;

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

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

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

  int32_t count = 0;
  nsIFrame* baseFrame = nullptr;
  nsIFrame* indexFrame = nullptr;
  nsHTMLReflowMetrics baseSize(aReflowState);
  nsHTMLReflowMetrics indexSize(aReflowState);
  nsIFrame* childFrame = mFrames.FirstChild();
  while (childFrame) {
    // ask our children to compute their bounding metrics 
    nsHTMLReflowMetrics childDesiredSize(aReflowState,
                                         aDesiredSize.mFlags
                                         | NS_REFLOW_CALC_BOUNDING_METRICS);
    WritingMode wm = childFrame->GetWritingMode();
    LogicalSize availSize = aReflowState.ComputedSize(wm);
    availSize.BSize(wm) = NS_UNCONSTRAINEDSIZE;
    nsHTMLReflowState childReflowState(aPresContext, aReflowState,
                                       childFrame, availSize);
    ReflowChild(childFrame, aPresContext,
                     childDesiredSize, childReflowState, childStatus);
    //NS_ASSERTION(NS_FRAME_IS_COMPLETE(childStatus), "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 = NS_FRAME_COMPLETE;
    NS_FRAME_SET_TRUNCATION(aStatus, aReflowState, 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;

//.........这里部分代码省略.........

void
nsHTMLButtonControlFrame::ReflowButtonContents(nsPresContext* aPresContext,
                                               nsHTMLReflowMetrics& aButtonDesiredSize,
                                               const nsHTMLReflowState& aButtonReflowState,
                                               nsIFrame* aFirstKid)
{
  WritingMode wm = GetWritingMode();
  LogicalSize availSize = aButtonReflowState.ComputedSize(wm);
  availSize.BSize(wm) = NS_INTRINSICSIZE;

  // Buttons have some bonus renderer-determined border/padding,
  // which occupies part of the button's content-box area:
  LogicalMargin focusPadding =
    LogicalMargin(wm, mRenderer.GetAddedButtonBorderAndPadding());

  // See whether out availSize's inline-size is big enough.  If it's
  // smaller than our intrinsic min iSize, that means that the kid
  // wouldn't really fit.  In that case, we overflow into our internal
  // focuspadding (which other browsers don't have) so that there's a
  // little more space for it.
  // Note that GetMinISize includes the focusPadding.
  nscoord IOverflow = GetMinISize(aButtonReflowState.rendContext) -
                      aButtonReflowState.ComputedISize();
  nscoord IFocusPadding = focusPadding.IStartEnd(wm);
  nscoord focusPaddingReduction = std::min(IFocusPadding,
                                           std::max(IOverflow, 0));
  if (focusPaddingReduction > 0) {
    nscoord startReduction = focusPadding.IStart(wm);
    if (focusPaddingReduction != IFocusPadding) {
      startReduction = NSToCoordRound(startReduction *
                                      (float(focusPaddingReduction) /
                                       float(IFocusPadding)));
    }
    focusPadding.IStart(wm) -= startReduction;
    focusPadding.IEnd(wm) -= focusPaddingReduction - startReduction;
  }

  // shorthand for a value we need to use in a bunch of places
  const LogicalMargin& clbp = aButtonReflowState.ComputedLogicalBorderPadding();

  // Indent the child inside us by the focus border. We must do this separate
  // from the regular border.
  availSize.ISize(wm) -= focusPadding.IStartEnd(wm);

  LogicalPoint childPos(wm);
  childPos.I(wm) = focusPadding.IStart(wm) + clbp.IStart(wm);
  availSize.ISize(wm) = std::max(availSize.ISize(wm), 0);

  // Give child a clone of the button's reflow state, with height/width reduced
  // by focusPadding, so that descendants with height:100% don't protrude.
  nsHTMLReflowState adjustedButtonReflowState =
    CloneReflowStateWithReducedContentBox(aButtonReflowState,
                                          focusPadding.GetPhysicalMargin(wm));

  nsHTMLReflowState contentsReflowState(aPresContext,
                                        adjustedButtonReflowState,
                                        aFirstKid, availSize);

  nsReflowStatus contentsReflowStatus;
  nsHTMLReflowMetrics contentsDesiredSize(aButtonReflowState);
  childPos.B(wm) = 0; // This will be set properly later, after reflowing the
                      // child to determine its size.

  // We just pass a dummy containerSize here, as the child will be
  // repositioned later by FinishReflowChild.
  nsSize dummyContainerSize;
  ReflowChild(aFirstKid, aPresContext,
              contentsDesiredSize, contentsReflowState,
              wm, childPos, dummyContainerSize, 0, contentsReflowStatus);
  MOZ_ASSERT(NS_FRAME_IS_COMPLETE(contentsReflowStatus),
             "We gave button-contents frame unconstrained available height, "
             "so it should be complete");

  // Compute the button's content-box size:
  LogicalSize buttonContentBox(wm);
  if (aButtonReflowState.ComputedBSize() != NS_INTRINSICSIZE) {
    // Button has a fixed block-size -- that's its content-box bSize.
    buttonContentBox.BSize(wm) = aButtonReflowState.ComputedBSize();
  } else {
    // Button is intrinsically sized -- it should shrinkwrap the
    // button-contents' bSize, plus any focus-padding space:
    buttonContentBox.BSize(wm) =
      contentsDesiredSize.BSize(wm) + focusPadding.BStartEnd(wm);

    // Make sure we obey min/max-bSize in the case when we're doing intrinsic
    // sizing (we get it for free when we have a non-intrinsic
    // aButtonReflowState.ComputedBSize()).  Note that we do this before
    // adjusting for borderpadding, since mComputedMaxBSize and
    // mComputedMinBSize are content bSizes.
    buttonContentBox.BSize(wm) =
      NS_CSS_MINMAX(buttonContentBox.BSize(wm),
                    aButtonReflowState.ComputedMinBSize(),
                    aButtonReflowState.ComputedMaxBSize());
  }
  if (aButtonReflowState.ComputedISize() != NS_INTRINSICSIZE) {
    buttonContentBox.ISize(wm) = aButtonReflowState.ComputedISize();
  } else {
    buttonContentBox.ISize(wm) =
      contentsDesiredSize.ISize(wm) + focusPadding.IStartEnd(wm);
    buttonContentBox.ISize(wm) =
//.........这里部分代码省略.........

void
nsProgressFrame::ReflowBarFrame(nsIFrame*                aBarFrame,
                                nsPresContext*           aPresContext,
                                const nsHTMLReflowState& aReflowState,
                                nsReflowStatus&          aStatus)
{
  bool vertical = ResolvedOrientationIsVertical();
  WritingMode wm = aBarFrame->GetWritingMode();
  LogicalSize availSize = aReflowState.ComputedSize(wm);
  availSize.BSize(wm) = NS_UNCONSTRAINEDSIZE;
  nsHTMLReflowState reflowState(aPresContext, aReflowState,
                                aBarFrame, availSize);
  nscoord size = vertical ? aReflowState.ComputedHeight()
                          : aReflowState.ComputedWidth();
  nscoord xoffset = aReflowState.ComputedPhysicalBorderPadding().left;
  nscoord yoffset = aReflowState.ComputedPhysicalBorderPadding().top;

  double position = static_cast<HTMLProgressElement*>(mContent)->Position();

  // Force the bar's size to match the current progress.
  // When indeterminate, the progress' size will be 100%.
  if (position >= 0.0) {
    size *= position;
  }

  if (!vertical && (wm.IsVertical() ? wm.IsVerticalRL() : !wm.IsBidiLTR())) {
    xoffset += aReflowState.ComputedWidth() - size;
  }

  // The bar size is fixed in these cases:
  // - the progress position is determined: the bar size is fixed according
  //   to it's value.
  // - the progress position is indeterminate and the bar appearance should be
  //   shown as native: the bar size is forced to 100%.
  // Otherwise (when the progress is indeterminate and the bar appearance isn't
  // native), the bar size isn't fixed and can be set by the author.
  if (position != -1 || ShouldUseNativeStyle()) {
    if (vertical) {
      // We want the bar to begin at the bottom.
      yoffset += aReflowState.ComputedHeight() - size;

      size -= reflowState.ComputedPhysicalMargin().TopBottom() +
              reflowState.ComputedPhysicalBorderPadding().TopBottom();
      size = std::max(size, 0);
      reflowState.SetComputedHeight(size);
    } else {
      size -= reflowState.ComputedPhysicalMargin().LeftRight() +
              reflowState.ComputedPhysicalBorderPadding().LeftRight();
      size = std::max(size, 0);
      reflowState.SetComputedWidth(size);
    }
  } else if (vertical) {
    // For vertical progress bars, we need to position the bar specificly when
    // the width isn't constrained (position == -1 and !ShouldUseNativeStyle())
    // because aReflowState.ComputedHeight() - size == 0.
    yoffset += aReflowState.ComputedHeight() - reflowState.ComputedHeight();
  }

  xoffset += reflowState.ComputedPhysicalMargin().left;
  yoffset += reflowState.ComputedPhysicalMargin().top;

  nsHTMLReflowMetrics barDesiredSize(aReflowState);
  ReflowChild(aBarFrame, aPresContext, barDesiredSize, reflowState, xoffset,
              yoffset, 0, aStatus);
  FinishReflowChild(aBarFrame, aPresContext, barDesiredSize, &reflowState,
                    xoffset, yoffset, 0);
}

void
nsHTMLButtonControlFrame::ReflowButtonContents(nsPresContext* aPresContext,
        nsHTMLReflowMetrics& aButtonDesiredSize,
        const nsHTMLReflowState& aButtonReflowState,
        nsIFrame* aFirstKid)
{
    WritingMode wm = GetWritingMode();
    bool isVertical = wm.IsVertical();
    LogicalSize availSize = aButtonReflowState.ComputedSize(wm);
    availSize.BSize(wm) = NS_INTRINSICSIZE;

    // Buttons have some bonus renderer-determined border/padding,
    // which occupies part of the button's content-box area:
    const LogicalMargin focusPadding =
        LogicalMargin(wm, mRenderer.GetAddedButtonBorderAndPadding());

    // shorthand for a value we need to use in a bunch of places
    const LogicalMargin& clbp = aButtonReflowState.ComputedLogicalBorderPadding();

    // Indent the child inside us by the focus border. We must do this separate
    // from the regular border.
    availSize.ISize(wm) -= focusPadding.IStartEnd(wm);

    // See whether out availSize's inline-size is big enough.  If it's smaller than
    // our intrinsic min iSize, that means that the kid wouldn't really fit; for a
    // better look in such cases we adjust the available iSize and our inline-start
    // offset to allow the kid to spill start-wards into our padding.
    nscoord ioffset = focusPadding.IStart(wm) + clbp.IStart(wm);
    nscoord extraISize = GetMinISize(aButtonReflowState.rendContext) -
                         aButtonReflowState.ComputedISize();
    if (extraISize > 0) {
        nscoord extraIStart = extraISize / 2;
        nscoord extraIEnd = extraISize - extraIStart;
        NS_ASSERTION(extraIEnd >=0, "How'd that happen?");

        // Do not allow the extras to be bigger than the relevant padding
        const LogicalMargin& padding = aButtonReflowState.ComputedLogicalPadding();
        extraIStart = std::min(extraIStart, padding.IStart(wm));
        extraIEnd = std::min(extraIEnd, padding.IEnd(wm));
        ioffset -= extraIStart;
        availSize.ISize(wm) = availSize.ISize(wm) + extraIStart + extraIEnd;
    }
    availSize.ISize(wm) = std::max(availSize.ISize(wm), 0);

    // Give child a clone of the button's reflow state, with height/width reduced
    // by focusPadding, so that descendants with height:100% don't protrude.
    nsHTMLReflowState adjustedButtonReflowState =
        CloneReflowStateWithReducedContentBox(aButtonReflowState,
                focusPadding.GetPhysicalMargin(wm));

    nsHTMLReflowState contentsReflowState(aPresContext,
                                          adjustedButtonReflowState,
                                          aFirstKid, availSize);

    nsReflowStatus contentsReflowStatus;
    nsHTMLReflowMetrics contentsDesiredSize(aButtonReflowState);
    nscoord boffset = focusPadding.BStart(wm) + clbp.BStart(wm);
    ReflowChild(aFirstKid, aPresContext,
                contentsDesiredSize, contentsReflowState,
                isVertical ? boffset : ioffset,
                isVertical ? ioffset : boffset,
                0, contentsReflowStatus);
    MOZ_ASSERT(NS_FRAME_IS_COMPLETE(contentsReflowStatus),
               "We gave button-contents frame unconstrained available height, "
               "so it should be complete");

    // Compute the button's content-box height:
    nscoord buttonContentBoxBSize = 0;
    if (aButtonReflowState.ComputedBSize() != NS_INTRINSICSIZE) {
        // Button has a fixed block-size -- that's its content-box bSize.
        buttonContentBoxBSize = aButtonReflowState.ComputedBSize();
    } else {
        // Button is intrinsically sized -- it should shrinkwrap the
        // button-contents' bSize, plus any focus-padding space:
        buttonContentBoxBSize =
            contentsDesiredSize.BSize(wm) + focusPadding.BStartEnd(wm);

        // Make sure we obey min/max-bSize in the case when we're doing intrinsic
        // sizing (we get it for free when we have a non-intrinsic
        // aButtonReflowState.ComputedBSize()).  Note that we do this before
        // adjusting for borderpadding, since mComputedMaxBSize and
        // mComputedMinBSize are content bSizes.
        buttonContentBoxBSize =
            NS_CSS_MINMAX(buttonContentBoxBSize,
                          aButtonReflowState.ComputedMinBSize(),
                          aButtonReflowState.ComputedMaxBSize());
    }

    // Center child in the block-direction in the button
    // (technically, inside of the button's focus-padding area)
    nscoord extraSpace =
        buttonContentBoxBSize - focusPadding.BStartEnd(wm) -
        contentsDesiredSize.BSize(wm);

    boffset = std::max(0, extraSpace / 2);

    // Adjust boffset to be in terms of the button's frame-rect, instead of
    // its focus-padding rect:
    boffset += focusPadding.BStart(wm) + clbp.BStart(wm);

//.........这里部分代码省略.........

void
nsNumberControlFrame::Reflow(nsPresContext* aPresContext,
                             nsHTMLReflowMetrics& aDesiredSize,
                             const nsHTMLReflowState& aReflowState,
                             nsReflowStatus& aStatus)
{
  DO_GLOBAL_REFLOW_COUNT("nsNumberControlFrame");
  DISPLAY_REFLOW(aPresContext, this, aReflowState, aDesiredSize, aStatus);

  NS_ASSERTION(mOuterWrapper, "Outer wrapper div must exist!");

  NS_ASSERTION(!GetPrevContinuation() && !GetNextContinuation(),
               "nsNumberControlFrame should not have continuations; if it does we "
               "need to call RegUnregAccessKey only for the first");

  NS_ASSERTION(!mFrames.FirstChild() ||
               !mFrames.FirstChild()->GetNextSibling(),
               "We expect at most one direct child frame");

  if (mState & NS_FRAME_FIRST_REFLOW) {
    nsFormControlFrame::RegUnRegAccessKey(this, true);
  }

  // The width of our content box, which is the available width
  // for our anonymous content:
  const nscoord contentBoxWidth = aReflowState.ComputedWidth();
  nscoord contentBoxHeight = aReflowState.ComputedHeight();

  nsIFrame* outerWrapperFrame = mOuterWrapper->GetPrimaryFrame();

  if (!outerWrapperFrame) { // display:none?
    if (contentBoxHeight == NS_INTRINSICSIZE) {
      contentBoxHeight = 0;
    }
  } else {
    NS_ASSERTION(outerWrapperFrame == mFrames.FirstChild(), "huh?");

    nsHTMLReflowMetrics wrappersDesiredSize(aReflowState);

    WritingMode wm = outerWrapperFrame->GetWritingMode();
    LogicalSize availSize = aReflowState.ComputedSize(wm);
    availSize.BSize(wm) = NS_UNCONSTRAINEDSIZE;

    nsHTMLReflowState wrapperReflowState(aPresContext, aReflowState,
                                         outerWrapperFrame, availSize);

    // offsets of wrapper frame
    nscoord xoffset = aReflowState.ComputedPhysicalBorderPadding().left +
                        wrapperReflowState.ComputedPhysicalMargin().left;
    nscoord yoffset = aReflowState.ComputedPhysicalBorderPadding().top +
                        wrapperReflowState.ComputedPhysicalMargin().top;

    nsReflowStatus childStatus;
    ReflowChild(outerWrapperFrame, aPresContext, wrappersDesiredSize,
                wrapperReflowState, xoffset, yoffset, 0, childStatus);
    MOZ_ASSERT(NS_FRAME_IS_FULLY_COMPLETE(childStatus),
               "We gave our child unconstrained height, so it should be complete");

    nscoord wrappersMarginBoxHeight = wrappersDesiredSize.Height() +
      wrapperReflowState.ComputedPhysicalMargin().TopBottom();

    if (contentBoxHeight == NS_INTRINSICSIZE) {
      // We are intrinsically sized -- we should shrinkwrap the outer wrapper's
      // height:
      contentBoxHeight = wrappersMarginBoxHeight;

      // Make sure we obey min/max-height in the case when we're doing intrinsic
      // sizing (we get it for free when we have a non-intrinsic
      // aReflowState.ComputedHeight()).  Note that we do this before
      // adjusting for borderpadding, since mComputedMaxHeight and
      // mComputedMinHeight are content heights.
      contentBoxHeight =
        NS_CSS_MINMAX(contentBoxHeight,
                      aReflowState.ComputedMinHeight(),
                      aReflowState.ComputedMaxHeight());
    }

    // Center child vertically
    nscoord extraSpace = contentBoxHeight - wrappersMarginBoxHeight;
    yoffset += std::max(0, extraSpace / 2);

    // Place the child
    FinishReflowChild(outerWrapperFrame, aPresContext, wrappersDesiredSize,
                      &wrapperReflowState, xoffset, yoffset, 0);

    aDesiredSize.SetBlockStartAscent(
       wrappersDesiredSize.BlockStartAscent() +
       outerWrapperFrame->BStart(aReflowState.GetWritingMode(),
                                 contentBoxWidth));
  }

  aDesiredSize.Width() = contentBoxWidth +
                         aReflowState.ComputedPhysicalBorderPadding().LeftRight();
  aDesiredSize.Height() = contentBoxHeight +
                          aReflowState.ComputedPhysicalBorderPadding().TopBottom();

  aDesiredSize.SetOverflowAreasToDesiredBounds();

  if (outerWrapperFrame) {
    ConsiderChildOverflow(aDesiredSize.mOverflowAreas, outerWrapperFrame);
//.........这里部分代码省略.........

//.........这里部分代码省略.........
        line = block->begin_lines();
        line_end = block->end_lines();
      }
      for (; anyLines && line != line_end; ++line) {
        if (!aClearanceFrame && line->HasClearance()) {
          // If we don't have a clearance frame, then we're computing
          // the collapsed margin in the first pass, assuming that all
          // lines have no clearance. So clear their clearance flags.
          line->ClearHasClearance();
          line->MarkDirty();
          dirtiedLine = true;
        }

        bool isEmpty;
        if (line->IsInline()) {
          isEmpty = line->IsEmpty();
        } else {
          nsIFrame* kid = line->mFirstChild;
          if (kid == aClearanceFrame) {
            line->SetHasClearance();
            line->MarkDirty();
            dirtiedLine = true;
            goto done;
          }
          // Here is where we recur. Now that we have determined that a
          // generational collapse is required we need to compute the
          // child blocks margin and so in so that we can look into
          // it. For its margins to be computed we need to have a reflow
          // state for it.

          // We may have to construct an extra reflow state here if
          // we drilled down through a block wrapper. At the moment
          // we can only drill down one level so we only have to support
          // one extra reflow state.
          const nsHTMLReflowState* outerReflowState = &aRS;
          if (frame != aRS.frame) {
            NS_ASSERTION(frame->GetParent() == aRS.frame,
                         "Can only drill through one level of block wrapper");
            LogicalSize availSpace = aRS.ComputedSize(frame->GetWritingMode());
            outerReflowState = new nsHTMLReflowState(prescontext,
                                                     aRS, frame, availSpace);
          }
          {
            LogicalSize availSpace =
              outerReflowState->ComputedSize(kid->GetWritingMode());
            nsHTMLReflowState innerReflowState(prescontext,
                                               *outerReflowState, kid,
                                               availSpace);
            // Record that we're being optimistic by assuming the kid
            // has no clearance
            if (kid->StyleDisplay()->mBreakType != NS_STYLE_CLEAR_NONE) {
              *aMayNeedRetry = true;
            }
            if (ComputeCollapsedBStartMargin(innerReflowState, aMargin,
                                             aClearanceFrame, aMayNeedRetry,
                                             &isEmpty)) {
              line->MarkDirty();
              dirtiedLine = true;
            }
            if (isEmpty) {
              WritingMode innerWM = innerReflowState.GetWritingMode();
              LogicalMargin innerMargin =
                innerReflowState.ComputedLogicalMargin().ConvertTo(parentWM, innerWM);
              aMargin->Include(innerMargin.BEnd(parentWM));
            }
          }
          if (outerReflowState != &aRS) {
            delete const_cast<nsHTMLReflowState*>(outerReflowState);
          }
        }
        if (!isEmpty) {
          if (!setBlockIsEmpty && aBlockIsEmpty) {
            setBlockIsEmpty = true;
            *aBlockIsEmpty = false;
          }
          goto done;
        }
      }
      if (!setBlockIsEmpty && aBlockIsEmpty) {
        // The first time we reach here is when this is the first block
        // and we have processed all its normal lines.
        setBlockIsEmpty = true;
        // All lines are empty, or we wouldn't be here!
        *aBlockIsEmpty = aRS.frame->IsSelfEmpty();
      }
    }
  }
  done:

  if (!setBlockIsEmpty && aBlockIsEmpty) {
    *aBlockIsEmpty = aRS.frame->IsEmpty();
  }
  
#ifdef NOISY_BLOCKDIR_MARGINS
  nsFrame::ListTag(stdout, aRS.frame);
  printf(": => %d\n", aMargin->get());
#endif

  return dirtiedLine;
}

void
nsNumberControlFrame::Reflow(nsPresContext* aPresContext,
                             nsHTMLReflowMetrics& aDesiredSize,
                             const nsHTMLReflowState& aReflowState,
                             nsReflowStatus& aStatus)
{
    MarkInReflow();
    DO_GLOBAL_REFLOW_COUNT("nsNumberControlFrame");
    DISPLAY_REFLOW(aPresContext, this, aReflowState, aDesiredSize, aStatus);

    NS_ASSERTION(mOuterWrapper, "Outer wrapper div must exist!");

    NS_ASSERTION(!GetPrevContinuation() && !GetNextContinuation(),
                 "nsNumberControlFrame should not have continuations; if it does we "
                 "need to call RegUnregAccessKey only for the first");

    NS_ASSERTION(!mFrames.FirstChild() ||
                 !mFrames.FirstChild()->GetNextSibling(),
                 "We expect at most one direct child frame");

    if (mState & NS_FRAME_FIRST_REFLOW) {
        nsFormControlFrame::RegUnRegAccessKey(this, true);
    }

    const WritingMode myWM = aReflowState.GetWritingMode();

    // The ISize of our content box, which is the available ISize
    // for our anonymous content:
    const nscoord contentBoxISize = aReflowState.ComputedISize();
    nscoord contentBoxBSize = aReflowState.ComputedBSize();

    // Figure out our border-box sizes as well (by adding borderPadding to
    // content-box sizes):
    const nscoord borderBoxISize = contentBoxISize +
                                   aReflowState.ComputedLogicalBorderPadding().IStartEnd(myWM);

    nscoord borderBoxBSize;
    if (contentBoxBSize != NS_INTRINSICSIZE) {
        borderBoxBSize = contentBoxBSize +
                         aReflowState.ComputedLogicalBorderPadding().BStartEnd(myWM);
    } // else, we'll figure out borderBoxBSize after we resolve contentBoxBSize.

    nsIFrame* outerWrapperFrame = mOuterWrapper->GetPrimaryFrame();

    if (!outerWrapperFrame) { // display:none?
        if (contentBoxBSize == NS_INTRINSICSIZE) {
            contentBoxBSize = 0;
            borderBoxBSize =
                aReflowState.ComputedLogicalBorderPadding().BStartEnd(myWM);
        }
    } else {
        NS_ASSERTION(outerWrapperFrame == mFrames.FirstChild(), "huh?");

        nsHTMLReflowMetrics wrappersDesiredSize(aReflowState);

        WritingMode wrapperWM = outerWrapperFrame->GetWritingMode();
        LogicalSize availSize = aReflowState.ComputedSize(wrapperWM);
        availSize.BSize(wrapperWM) = NS_UNCONSTRAINEDSIZE;

        nsHTMLReflowState wrapperReflowState(aPresContext, aReflowState,
                                             outerWrapperFrame, availSize);

        // Convert wrapper margin into my own writing-mode (in case it differs):
        LogicalMargin wrapperMargin =
            wrapperReflowState.ComputedLogicalMargin().ConvertTo(myWM, wrapperWM);

        // offsets of wrapper frame within this frame:
        LogicalPoint
        wrapperOffset(myWM,
                      aReflowState.ComputedLogicalBorderPadding().IStart(myWM) +
                      wrapperMargin.IStart(myWM),
                      aReflowState.ComputedLogicalBorderPadding().BStart(myWM) +
                      wrapperMargin.BStart(myWM));

        nsReflowStatus childStatus;
        // We initially reflow the child with a dummy containerSize; positioning
        // will be fixed later.
        const nsSize dummyContainerSize;
        ReflowChild(outerWrapperFrame, aPresContext, wrappersDesiredSize,
                    wrapperReflowState, myWM, wrapperOffset, dummyContainerSize, 0,
                    childStatus);
        MOZ_ASSERT(NS_FRAME_IS_FULLY_COMPLETE(childStatus),
                   "We gave our child unconstrained available block-size, "
                   "so it should be complete");

        nscoord wrappersMarginBoxBSize =
            wrappersDesiredSize.BSize(myWM) + wrapperMargin.BStartEnd(myWM);

        if (contentBoxBSize == NS_INTRINSICSIZE) {
            // We are intrinsically sized -- we should shrinkwrap the outer wrapper's
            // block-size:
            contentBoxBSize = wrappersMarginBoxBSize;

            // Make sure we obey min/max-bsize in the case when we're doing intrinsic
            // sizing (we get it for free when we have a non-intrinsic
            // aReflowState.ComputedBSize()).  Note that we do this before
            // adjusting for borderpadding, since ComputedMaxBSize and
            // ComputedMinBSize are content heights.
            contentBoxBSize =
                NS_CSS_MINMAX(contentBoxBSize,
//.........这里部分代码省略.........

//.........这里部分代码省略.........
    // boundary, but if so, too bad, this optimization is defeated.)
    // We want scrollable overflow here since this is a calculation that
    // affects layout.
    bool skipResizeHeightShrink = shrinkingHeightOnly
      && child->GetScrollableOverflowRect().YMost() <= aConfig.mColMaxHeight;

    nscoord childContentBEnd = 0;
    WritingMode wm = child->GetWritingMode();
    if (!reflowNext && (skipIncremental || skipResizeHeightShrink)) {
      // This child does not need to be reflowed, but we may need to move it
      MoveChildTo(this, child, childOrigin);
      
      // If this is the last frame then make sure we get the right status
      nsIFrame* kidNext = child->GetNextSibling();
      if (kidNext) {
        aStatus = (kidNext->GetStateBits() & NS_FRAME_IS_OVERFLOW_CONTAINER)
                  ? NS_FRAME_OVERFLOW_INCOMPLETE
                  : NS_FRAME_NOT_COMPLETE;
      } else {
        aStatus = mLastFrameStatus;
      }
      childContentBEnd = nsLayoutUtils::CalculateContentBEnd(wm, child);
#ifdef DEBUG_roc
      printf("*** Skipping child #%d %p (incremental %d, resize height shrink %d): status = %d\n",
             columnCount, (void*)child, skipIncremental, skipResizeHeightShrink, aStatus);
#endif
    } else {
      nsSize physicalSize(aConfig.mColWidth, aConfig.mColMaxHeight);

      if (aUnboundedLastColumn && columnCount == aConfig.mBalanceColCount - 1) {
        physicalSize.height = GetAvailableContentHeight(aReflowState);
      }
      LogicalSize availSize(wm, physicalSize);
      LogicalSize computedSize = aReflowState.ComputedSize(wm);

      if (reflowNext)
        child->AddStateBits(NS_FRAME_IS_DIRTY);

      nsHTMLReflowState kidReflowState(PresContext(), aReflowState, child,
                                       availSize, availSize.ISize(wm),
                                       computedSize.BSize(wm));
      kidReflowState.mFlags.mIsTopOfPage = true;
      kidReflowState.mFlags.mTableIsSplittable = false;
      kidReflowState.mFlags.mIsColumnBalancing = aConfig.mBalanceColCount < INT32_MAX;

      // We need to reflow any float placeholders, even if our column height
      // hasn't changed.
      kidReflowState.mFlags.mMustReflowPlaceholders = !colHeightChanged;

#ifdef DEBUG_roc
      printf("*** Reflowing child #%d %p: availHeight=%d\n",
             columnCount, (void*)child,availSize.BSize(wm));
#endif

      // Note if the column's next in flow is not being changed by this incremental reflow.
      // This may allow the current column to avoid trying to pull lines from the next column.
      if (child->GetNextSibling() &&
          !(GetStateBits() & NS_FRAME_IS_DIRTY) &&
        !(child->GetNextSibling()->GetStateBits() & NS_FRAME_IS_DIRTY)) {
        kidReflowState.mFlags.mNextInFlowUntouched = true;
      }

      nsHTMLReflowMetrics kidDesiredSize(wm, aDesiredSize.mFlags);

      // XXX it would be cool to consult the float manager for the
      // previous block to figure out the region of floats from the

void
nsAbsoluteContainingBlock::ReflowAbsoluteFrame(nsIFrame*                aDelegatingFrame,
                                               nsPresContext*           aPresContext,
                                               const nsHTMLReflowState& aReflowState,
                                               const nsRect&            aContainingBlock,
                                               bool                     aConstrainHeight,
                                               nsIFrame*                aKidFrame,
                                               nsReflowStatus&          aStatus,
                                               nsOverflowAreas*         aOverflowAreas)
{
#ifdef DEBUG
  if (nsBlockFrame::gNoisyReflow) {
    nsFrame::IndentBy(stdout,nsBlockFrame::gNoiseIndent);
    printf("abs pos ");
    if (aKidFrame) {
      nsAutoString name;
      aKidFrame->GetFrameName(name);
      printf("%s ", NS_LossyConvertUTF16toASCII(name).get());
    }

    char width[16];
    char height[16];
    PrettyUC(aReflowState.AvailableWidth(), width);
    PrettyUC(aReflowState.AvailableHeight(), height);
    printf(" a=%s,%s ", width, height);
    PrettyUC(aReflowState.ComputedWidth(), width);
    PrettyUC(aReflowState.ComputedHeight(), height);
    printf("c=%s,%s \n", width, height);
  }
  AutoNoisyIndenter indent(nsBlockFrame::gNoisy);
#endif // DEBUG

  WritingMode wm = aKidFrame->GetWritingMode();
  nscoord availISize = LogicalSize(wm, aContainingBlock.Size()).ISize(wm);
  if (availISize == -1) {
    NS_ASSERTION(aReflowState.ComputedSize(wm).ISize(wm) !=
                   NS_UNCONSTRAINEDSIZE,
                 "Must have a useful inline-size _somewhere_");
    availISize =
      aReflowState.ComputedSizeWithPadding(wm).ISize(wm);
  }

  nsHTMLReflowMetrics kidDesiredSize(aReflowState);
  nsHTMLReflowState kidReflowState(aPresContext, aReflowState, aKidFrame,
                                   LogicalSize(wm, availISize,
                                               NS_UNCONSTRAINEDSIZE),
                                   aContainingBlock.width,
                                   aContainingBlock.height);

  // Get the border values
  const nsMargin& border = aReflowState.mStyleBorder->GetComputedBorder();

  bool constrainHeight = (aReflowState.AvailableHeight() != NS_UNCONSTRAINEDSIZE)
    && aConstrainHeight
       // Don't split if told not to (e.g. for fixed frames)
    && (aDelegatingFrame->GetType() != nsGkAtoms::inlineFrame)
       //XXX we don't handle splitting frames for inline absolute containing blocks yet
    && (aKidFrame->GetRect().y <= aReflowState.AvailableHeight());
       // Don't split things below the fold. (Ideally we shouldn't *have*
       // anything totally below the fold, but we can't position frames
       // across next-in-flow breaks yet.
  if (constrainHeight) {
    kidReflowState.AvailableHeight() = aReflowState.AvailableHeight() - border.top
                                     - kidReflowState.ComputedPhysicalMargin().top;
    if (NS_AUTOOFFSET != kidReflowState.ComputedPhysicalOffsets().top)
      kidReflowState.AvailableHeight() -= kidReflowState.ComputedPhysicalOffsets().top;
  }

  // Do the reflow
  aKidFrame->Reflow(aPresContext, kidDesiredSize, kidReflowState, aStatus);

  // If we're solving for 'left' or 'top', then compute it now that we know the
  // width/height
  if ((NS_AUTOOFFSET == kidReflowState.ComputedPhysicalOffsets().left) ||
      (NS_AUTOOFFSET == kidReflowState.ComputedPhysicalOffsets().top)) {
    nscoord aContainingBlockWidth = aContainingBlock.width;
    nscoord aContainingBlockHeight = aContainingBlock.height;

    if (-1 == aContainingBlockWidth) {
      // Get the containing block width/height
      kidReflowState.ComputeContainingBlockRectangle(aPresContext,
                                                     &aReflowState,
                                                     aContainingBlockWidth,
                                                     aContainingBlockHeight);
    }

    if (NS_AUTOOFFSET == kidReflowState.ComputedPhysicalOffsets().left) {
      NS_ASSERTION(NS_AUTOOFFSET != kidReflowState.ComputedPhysicalOffsets().right,
                   "Can't solve for both left and right");
      kidReflowState.ComputedPhysicalOffsets().left = aContainingBlockWidth -
                                             kidReflowState.ComputedPhysicalOffsets().right -
                                             kidReflowState.ComputedPhysicalMargin().right -
                                             kidDesiredSize.Width() -
                                             kidReflowState.ComputedPhysicalMargin().left;
    }
    if (NS_AUTOOFFSET == kidReflowState.ComputedPhysicalOffsets().top) {
      kidReflowState.ComputedPhysicalOffsets().top = aContainingBlockHeight -
                                            kidReflowState.ComputedPhysicalOffsets().bottom -
                                            kidReflowState.ComputedPhysicalMargin().bottom -
                                            kidDesiredSize.Height() -
//.........这里部分代码省略.........

void
nsMathMLmfencedFrame::Reflow(nsPresContext*          aPresContext,
                             nsHTMLReflowMetrics&     aDesiredSize,
                             const nsHTMLReflowState& aReflowState,
                             nsReflowStatus&          aStatus)
{
  MarkInReflow();
  mPresentationData.flags &= ~NS_MATHML_ERROR;
  aDesiredSize.ClearSize();
  aDesiredSize.SetBlockStartAscent(0);
  aDesiredSize.mBoundingMetrics = nsBoundingMetrics();

  int32_t i;
  const nsStyleFont* font = StyleFont();
  float fontSizeInflation = nsLayoutUtils::FontSizeInflationFor(this);
  RefPtr<nsFontMetrics> fm;
  nsLayoutUtils::GetFontMetricsForFrame(this, getter_AddRefs(fm),
                                        fontSizeInflation);
  nscoord axisHeight, em;
  GetAxisHeight(*aReflowState.rendContext, fm, axisHeight);
  GetEmHeight(fm, em);
  // leading to be left at the top and the bottom of stretched chars
  nscoord leading = NSToCoordRound(0.2f * em); 

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

  // Note that we don't use the base method nsMathMLContainerFrame::Reflow()
  // because we want to stretch our fences, separators and stretchy frames using
  // the *same* initial aDesiredSize.mBoundingMetrics. If we were to use the base
  // method here, our stretchy frames will be stretched and placed, and we may
  // end up stretching our fences/separators with a different aDesiredSize.
  // XXX The above decision was revisited in bug 121748 and this code can be
  // refactored to use nsMathMLContainerFrame::Reflow() at some stage.

  nsReflowStatus childStatus;
  nsIFrame* firstChild = GetFirstPrincipalChild();
  nsIFrame* childFrame = firstChild;
  nscoord ascent = 0, descent = 0;
  if (firstChild || mOpenChar || mCloseChar || mSeparatorsCount > 0) {
    // We use the ASCII metrics to get our minimum height. This way,
    // if we have borders or a background, they will fit better with
    // other elements on the line.
    ascent = fm->MaxAscent();
    descent = fm->MaxDescent();
  }
  while (childFrame) {
    nsHTMLReflowMetrics childDesiredSize(aReflowState,
                                         aDesiredSize.mFlags
                                         | NS_REFLOW_CALC_BOUNDING_METRICS);
    WritingMode wm = childFrame->GetWritingMode();
    LogicalSize availSize = aReflowState.ComputedSize(wm);
    availSize.BSize(wm) = NS_UNCONSTRAINEDSIZE;
    nsHTMLReflowState childReflowState(aPresContext, aReflowState,
                                       childFrame, availSize);
    ReflowChild(childFrame, aPresContext, childDesiredSize,
                childReflowState, childStatus);
    //NS_ASSERTION(NS_FRAME_IS_COMPLETE(childStatus), "bad status");
    SaveReflowAndBoundingMetricsFor(childFrame, childDesiredSize,
                                    childDesiredSize.mBoundingMetrics);

    mozilla::WritingMode outerWM = aReflowState.GetWritingMode();
    nscoord childDescent = childDesiredSize.BSize(outerWM) -
                           childDesiredSize.BlockStartAscent();
    if (descent < childDescent)
      descent = childDescent;
    if (ascent < childDesiredSize.BlockStartAscent())
      ascent = childDesiredSize.BlockStartAscent();

    childFrame = childFrame->GetNextSibling();
  }

  /////////////
  // Ask stretchy children to stretch themselves

  nsBoundingMetrics containerSize;
  nsStretchDirection stretchDir = NS_STRETCH_DIRECTION_VERTICAL;

  GetPreferredStretchSize(*aReflowState.rendContext,
                          0, /* i.e., without embellishments */
                          stretchDir, containerSize);
  childFrame = firstChild;
  while (childFrame) {
    nsIMathMLFrame* mathmlChild = do_QueryFrame(childFrame);
    if (mathmlChild) {
      nsHTMLReflowMetrics childDesiredSize(aReflowState);
      // retrieve the metrics that was stored at the previous pass
      GetReflowAndBoundingMetricsFor(childFrame, childDesiredSize,
                                     childDesiredSize.mBoundingMetrics);
      
      mathmlChild->Stretch(*aReflowState.rendContext, 
                           stretchDir, containerSize, childDesiredSize);
      // store the updated metrics
      SaveReflowAndBoundingMetricsFor(childFrame, childDesiredSize,
                                      childDesiredSize.mBoundingMetrics);
      
      nscoord childDescent = childDesiredSize.Height() - childDesiredSize.BlockStartAscent();
      if (descent < childDescent)
        descent = childDescent;
//.........这里部分代码省略.........

void
nsAbsoluteContainingBlock::ReflowAbsoluteFrame(nsIFrame*                aDelegatingFrame,
                                               nsPresContext*           aPresContext,
                                               const nsHTMLReflowState& aReflowState,
                                               const nsRect&            aContainingBlock,
                                               AbsPosReflowFlags        aFlags,
                                               nsIFrame*                aKidFrame,
                                               nsReflowStatus&          aStatus,
                                               nsOverflowAreas*         aOverflowAreas)
{
#ifdef DEBUG
  if (nsBlockFrame::gNoisyReflow) {
    nsFrame::IndentBy(stdout,nsBlockFrame::gNoiseIndent);
    printf("abs pos ");
    if (aKidFrame) {
      nsAutoString name;
      aKidFrame->GetFrameName(name);
      printf("%s ", NS_LossyConvertUTF16toASCII(name).get());
    }

    char width[16];
    char height[16];
    PrettyUC(aReflowState.AvailableWidth(), width, 16);
    PrettyUC(aReflowState.AvailableHeight(), height, 16);
    printf(" a=%s,%s ", width, height);
    PrettyUC(aReflowState.ComputedWidth(), width, 16);
    PrettyUC(aReflowState.ComputedHeight(), height, 16);
    printf("c=%s,%s \n", width, height);
  }
  AutoNoisyIndenter indent(nsBlockFrame::gNoisy);
#endif // DEBUG

  WritingMode wm = aKidFrame->GetWritingMode();
  LogicalSize logicalCBSize(wm, aContainingBlock.Size());
  nscoord availISize = logicalCBSize.ISize(wm);
  if (availISize == -1) {
    NS_ASSERTION(aReflowState.ComputedSize(wm).ISize(wm) !=
                   NS_UNCONSTRAINEDSIZE,
                 "Must have a useful inline-size _somewhere_");
    availISize =
      aReflowState.ComputedSizeWithPadding(wm).ISize(wm);
  }

  uint32_t rsFlags = 0;
  if (aFlags & AbsPosReflowFlags::eIsGridContainerCB) {
    // When a grid container generates the abs.pos. CB for a *child* then
    // the static-position is the CB origin (i.e. of the grid area rect).
    // https://drafts.csswg.org/css-grid/#static-position
    nsIFrame* placeholder =
      aPresContext->PresShell()->GetPlaceholderFrameFor(aKidFrame);
    if (placeholder && placeholder->GetParent() == aDelegatingFrame) {
      rsFlags |= nsHTMLReflowState::STATIC_POS_IS_CB_ORIGIN;
    }
  }
  nsHTMLReflowState kidReflowState(aPresContext, aReflowState, aKidFrame,
                                   LogicalSize(wm, availISize,
                                               NS_UNCONSTRAINEDSIZE),
                                   &logicalCBSize, rsFlags);

  // Get the border values
  WritingMode outerWM = aReflowState.GetWritingMode();
  const LogicalMargin border(outerWM,
                             aReflowState.mStyleBorder->GetComputedBorder());
  const LogicalMargin margin =
    kidReflowState.ComputedLogicalMargin().ConvertTo(outerWM, wm);
  bool constrainBSize = (aReflowState.AvailableBSize() != NS_UNCONSTRAINEDSIZE)
    && (aFlags & AbsPosReflowFlags::eConstrainHeight)
       // Don't split if told not to (e.g. for fixed frames)
    && (aDelegatingFrame->GetType() != nsGkAtoms::inlineFrame)
       //XXX we don't handle splitting frames for inline absolute containing blocks yet
    && (aKidFrame->GetLogicalRect(aContainingBlock.Size()).BStart(wm) <=
        aReflowState.AvailableBSize());
       // Don't split things below the fold. (Ideally we shouldn't *have*
       // anything totally below the fold, but we can't position frames
       // across next-in-flow breaks yet.
  if (constrainBSize) {
    kidReflowState.AvailableBSize() =
      aReflowState.AvailableBSize() - border.ConvertTo(wm, outerWM).BStart(wm) -
      kidReflowState.ComputedLogicalMargin().BStart(wm);
    if (NS_AUTOOFFSET != kidReflowState.ComputedLogicalOffsets().BStart(wm)) {
      kidReflowState.AvailableBSize() -=
        kidReflowState.ComputedLogicalOffsets().BStart(wm);
    }
  }

  // Do the reflow
  nsHTMLReflowMetrics kidDesiredSize(kidReflowState);
  aKidFrame->Reflow(aPresContext, kidDesiredSize, kidReflowState, aStatus);

  const LogicalSize kidSize = kidDesiredSize.Size(wm).ConvertTo(outerWM, wm);

  LogicalMargin offsets =
    kidReflowState.ComputedLogicalOffsets().ConvertTo(outerWM, wm);

  // If we're solving for start in either inline or block direction,
  // then compute it now that we know the dimensions.
  if ((NS_AUTOOFFSET == offsets.IStart(outerWM)) ||
      (NS_AUTOOFFSET == offsets.BStart(outerWM))) {
    if (-1 == logicalCBSize.ISize(wm)) {
      // Get the containing block width/height
//.........这里部分代码省略.........