C++ ReflowOutput类代码示例

// Only reflow the selected child ...
void
nsMathMLSelectedFrame::Reflow(nsPresContext*          aPresContext,
                              ReflowOutput&     aDesiredSize,
                              const ReflowInput& aReflowInput,
                              nsReflowStatus&          aStatus)
{
  MarkInReflow();
  mPresentationData.flags &= ~NS_MATHML_ERROR;
  aStatus.Reset();
  aDesiredSize.ClearSize();
  aDesiredSize.SetBlockStartAscent(0);
  mBoundingMetrics = nsBoundingMetrics();
  nsIFrame* childFrame = GetSelectedFrame();
  if (childFrame) {
    WritingMode wm = childFrame->GetWritingMode();
    LogicalSize availSize = aReflowInput.ComputedSize(wm);
    availSize.BSize(wm) = NS_UNCONSTRAINEDSIZE;
    ReflowInput childReflowInput(aPresContext, aReflowInput,
                                       childFrame, availSize);
    ReflowChild(childFrame, aPresContext, aDesiredSize,
                childReflowInput, aStatus);
    SaveReflowAndBoundingMetricsFor(childFrame, aDesiredSize,
                                    aDesiredSize.mBoundingMetrics);
    mBoundingMetrics = aDesiredSize.mBoundingMetrics;
  }
  FinalizeReflow(aReflowInput.mRenderingContext->GetDrawTarget(), aDesiredSize);
  NS_FRAME_SET_TRUNCATION(aStatus, aReflowInput, aDesiredSize);
}

void
nsProgressFrame::Reflow(nsPresContext*           aPresContext,
                        ReflowOutput&     aDesiredSize,
                        const ReflowInput& aReflowInput,
                        nsReflowStatus&          aStatus)
{
  MarkInReflow();
  DO_GLOBAL_REFLOW_COUNT("nsProgressFrame");
  DISPLAY_REFLOW(aPresContext, this, aReflowInput, aDesiredSize, aStatus);

  NS_ASSERTION(mBarDiv, "Progress bar div must exist!");
  NS_ASSERTION(!GetPrevContinuation(),
               "nsProgressFrame should not have continuations; if it does we "
               "need to call RegUnregAccessKey only for the first.");

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

  nsIFrame* barFrame = mBarDiv->GetPrimaryFrame();
  NS_ASSERTION(barFrame, "The progress frame should have a child with a frame!");

  ReflowBarFrame(barFrame, aPresContext, aReflowInput, aStatus);

  aDesiredSize.SetSize(aReflowInput.GetWritingMode(),
                       aReflowInput.ComputedSizeWithBorderPadding());
  aDesiredSize.SetOverflowAreasToDesiredBounds();
  ConsiderChildOverflow(aDesiredSize.mOverflowAreas, barFrame);
  FinishAndStoreOverflow(&aDesiredSize);

  aStatus = NS_FRAME_COMPLETE;

  NS_FRAME_SET_TRUNCATION(aStatus, aReflowInput, aDesiredSize);
}

// Only place the selected child ...
/* virtual */ nsresult
nsMathMLSelectedFrame::Place(DrawTarget*          aDrawTarget,
                             bool                 aPlaceOrigin,
                             ReflowOutput& aDesiredSize)
{
  nsIFrame* childFrame = GetSelectedFrame();

  if (mInvalidMarkup) {
    return ReflowError(aDrawTarget, aDesiredSize);
  }

  aDesiredSize.ClearSize();
  aDesiredSize.SetBlockStartAscent(0);
  mBoundingMetrics = nsBoundingMetrics();
  if (childFrame) {
    GetReflowAndBoundingMetricsFor(childFrame, aDesiredSize, mBoundingMetrics);
    if (aPlaceOrigin) {
      FinishReflowChild(childFrame, PresContext(), aDesiredSize, nullptr, 0, 0, 0);
    }
    mReference.x = 0;
    mReference.y = aDesiredSize.BlockStartAscent();
  }
  aDesiredSize.mBoundingMetrics = mBoundingMetrics;
  return NS_OK;
}

void
nsSVGForeignObjectFrame::Reflow(nsPresContext*           aPresContext,
                                ReflowOutput&     aDesiredSize,
                                const ReflowInput& aReflowInput,
                                nsReflowStatus&          aStatus)
{
  MOZ_ASSERT(!(GetStateBits() & NS_FRAME_IS_NONDISPLAY),
             "Should not have been called");

  // Only InvalidateAndScheduleBoundsUpdate marks us with NS_FRAME_IS_DIRTY,
  // so if that bit is still set we still have a resize pending. If we hit
  // this assertion, then we should get the presShell to skip reflow roots
  // that have a dirty parent since a reflow is going to come via the
  // reflow root's parent anyway.
  NS_ASSERTION(!(GetStateBits() & NS_FRAME_IS_DIRTY),
               "Reflowing while a resize is pending is wasteful");

  // ReflowSVG makes sure mRect is up to date before we're called.

  NS_ASSERTION(!aReflowInput.mParentReflowInput,
               "should only get reflow from being reflow root");
  NS_ASSERTION(aReflowInput.ComputedWidth() == GetSize().width &&
               aReflowInput.ComputedHeight() == GetSize().height,
               "reflow roots should be reflowed at existing size and "
               "svg.css should ensure we have no padding/border/margin");

  DoReflow();

  WritingMode wm = aReflowInput.GetWritingMode();
  LogicalSize finalSize(wm, aReflowInput.ComputedISize(),
                        aReflowInput.ComputedBSize());
  aDesiredSize.SetSize(wm, finalSize);
  aDesiredSize.SetOverflowAreasToDesiredBounds();
  aStatus = NS_FRAME_COMPLETE;
}

static
void DebugCheckChildSize(nsIFrame*            aChild,
                         ReflowOutput& aMet)
{
  WritingMode wm = aMet.GetWritingMode();
  if ((aMet.ISize(wm) < 0) || (aMet.ISize(wm) > PROBABLY_TOO_LARGE)) {
    printf("WARNING: cell content %p has large inline size %d \n",
           static_cast<void*>(aChild), int32_t(aMet.ISize(wm)));
  }
}

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()));
}

/* virtual */ void
nsMathMLmrootFrame::GetIntrinsicISizeMetrics(nsRenderingContext* aRenderingContext, ReflowOutput& aDesiredSize)
{
  nsIFrame* baseFrame = mFrames.FirstChild();
  nsIFrame* indexFrame = nullptr;
  if (baseFrame)
    indexFrame = baseFrame->GetNextSibling();
  if (!indexFrame || indexFrame->GetNextSibling()) {
    ReflowError(aRenderingContext->GetDrawTarget(), aDesiredSize);
    return;
  }

  float fontSizeInflation = nsLayoutUtils::FontSizeInflationFor(this);
  nscoord baseWidth =
    nsLayoutUtils::IntrinsicForContainer(aRenderingContext, baseFrame,
                                         nsLayoutUtils::PREF_ISIZE);
  nscoord indexWidth =
    nsLayoutUtils::IntrinsicForContainer(aRenderingContext, indexFrame,
                                         nsLayoutUtils::PREF_ISIZE);
  nscoord sqrWidth = mSqrChar.GetMaxWidth(PresContext(),
                                          aRenderingContext->GetDrawTarget(),
                                          fontSizeInflation);

  nscoord dxSqr;
  RefPtr<nsFontMetrics> fm =
    nsLayoutUtils::GetFontMetricsForFrame(this, fontSizeInflation);
  GetRadicalXOffsets(indexWidth, sqrWidth, fm, nullptr, &dxSqr);

  nscoord width = dxSqr + sqrWidth + baseWidth;

  aDesiredSize.Width() = width;
  aDesiredSize.mBoundingMetrics.width = width;
  aDesiredSize.mBoundingMetrics.leftBearing = 0;
  aDesiredSize.mBoundingMetrics.rightBearing = width;
}

void
nsTableColGroupFrame::Reflow(nsPresContext*          aPresContext,
                             ReflowOutput&     aDesiredSize,
                             const ReflowInput& aReflowInput,
                             nsReflowStatus&          aStatus)
{
  MarkInReflow();
  DO_GLOBAL_REFLOW_COUNT("nsTableColGroupFrame");
  DISPLAY_REFLOW(aPresContext, this, aReflowInput, aDesiredSize, aStatus);
  NS_ASSERTION(nullptr!=mContent, "bad state -- null content for frame");
  
  const nsStyleVisibility* groupVis = StyleVisibility();
  bool collapseGroup = (NS_STYLE_VISIBILITY_COLLAPSE == groupVis->mVisible);
  if (collapseGroup) {
    GetTableFrame()->SetNeedToCollapse(true);
  }
  // for every content child that (is a column thingy and does not already have a frame)
  // create a frame and adjust it's style
  
  for (nsIFrame *kidFrame = mFrames.FirstChild(); kidFrame;
       kidFrame = kidFrame->GetNextSibling()) {
    // Give the child frame a chance to reflow, even though we know it'll have 0 size
    ReflowOutput kidSize(aReflowInput);
    ReflowInput kidReflowInput(aPresContext, aReflowInput, kidFrame,
                                     LogicalSize(kidFrame->GetWritingMode()));

    nsReflowStatus status;
    ReflowChild(kidFrame, aPresContext, kidSize, kidReflowInput, 0, 0, 0, status);
    FinishReflowChild(kidFrame, aPresContext, kidSize, nullptr, 0, 0, 0);
  }

  aDesiredSize.ClearSize();
  aStatus.Reset();
  NS_FRAME_SET_TRUNCATION(aStatus, aReflowInput, aDesiredSize);
}

void
nsTableWrapperFrame::UpdateOverflowAreas(ReflowOutput& aMet)
{
  aMet.SetOverflowAreasToDesiredBounds();
  ConsiderChildOverflow(aMet.mOverflowAreas, InnerTableFrame());
  if (mCaptionFrames.NotEmpty()) {
    ConsiderChildOverflow(aMet.mOverflowAreas, mCaptionFrames.FirstChild());
  }
}

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 availableISize so we don't cause a needless horizontal scrollbar.
  WritingMode wm = aReflowInput.GetWritingMode();
  nscoord scaledWidth = aWidth * PresContext()->GetPrintPreviewScale();
  nscoord scaledHeight = aHeight * PresContext()->GetPrintPreviewScale();

  nscoord scaledISize = (wm.IsVertical() ? scaledHeight : scaledWidth);
  nscoord scaledBSize = (wm.IsVertical() ? scaledWidth : scaledHeight);

  aDesiredSize.ISize(wm) = std::max(scaledISize, aReflowInput.AvailableISize());
  aDesiredSize.BSize(wm) = std::max(scaledBSize, aReflowInput.ComputedBSize());
}

/* virtual */ void
nsRubyTextFrame::Reflow(nsPresContext* aPresContext,
                        ReflowOutput& aDesiredSize,
                        const ReflowInput& aReflowInput,
                        nsReflowStatus& aStatus)
{
  // Even if we want to hide this frame, we have to reflow it first.
  // If we leave it dirty, changes to its content will never be
  // propagated to the ancestors, then it won't be displayed even if
  // the content is no longer the same, until next reflow triggered by
  // some other change. In general, we always reflow all the frames we
  // created. There might be other problems if we don't do that.
  nsRubyContentFrame::Reflow(aPresContext, aDesiredSize, aReflowInput, aStatus);

  if (IsAutoHidden()) {
    // Reset the ISize. The BSize is not changed so that it won't
    // affect vertical positioning in unexpected way.
    WritingMode lineWM = aReflowInput.mLineLayout->GetWritingMode();
    aDesiredSize.ISize(lineWM) = 0;
    aDesiredSize.SetOverflowAreasToDesiredBounds();
  }
}

void
nsPlaceholderFrame::Reflow(nsPresContext*           aPresContext,
                           ReflowOutput&     aDesiredSize,
                           const ReflowInput& aReflowInput,
                           nsReflowStatus&          aStatus)
{
#ifdef DEBUG
  // We should be getting reflowed before our out-of-flow.
  // If this is our first reflow, and our out-of-flow has already received its
  // first reflow (before us), complain.
  // XXXdholbert This "look for a previous continuation or IB-split sibling"
  // code could use nsLayoutUtils::GetPrevContinuationOrIBSplitSibling(), if
  // we ever add a function like that. (We currently have a "Next" version.)
  if ((GetStateBits() & NS_FRAME_FIRST_REFLOW) &&
      !(mOutOfFlowFrame->GetStateBits() & NS_FRAME_FIRST_REFLOW)) {

    // Unfortunately, this can currently happen when the placeholder is in a
    // later continuation or later IB-split sibling than its out-of-flow (as
    // is the case in some of our existing unit tests). So for now, in that
    // case, we'll warn instead of asserting.
    bool isInContinuationOrIBSplit = false;
    nsIFrame* ancestor = this;
    while ((ancestor = ancestor->GetParent())) {
      if (ancestor->GetPrevContinuation() ||
          ancestor->Properties().Get(IBSplitPrevSibling())) {
        isInContinuationOrIBSplit = true;
        break;
      }
    }

    if (isInContinuationOrIBSplit) {
      NS_WARNING("Out-of-flow frame got reflowed before its placeholder");
    } else {
      NS_ERROR("Out-of-flow frame got reflowed before its placeholder");
    }
  }
#endif

  MarkInReflow();
  DO_GLOBAL_REFLOW_COUNT("nsPlaceholderFrame");
  DISPLAY_REFLOW(aPresContext, this, aReflowInput, aDesiredSize, aStatus);
  aDesiredSize.ClearSize();

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

/* virtual */ void
nsBackdropFrame::Reflow(nsPresContext* aPresContext,
                        ReflowOutput& aDesiredSize,
                        const ReflowInput& aReflowInput,
                        nsReflowStatus& aStatus)
{
  MarkInReflow();
  DO_GLOBAL_REFLOW_COUNT("nsBackdropFrame");
  DISPLAY_REFLOW(aPresContext, this, aReflowInput, aDesiredSize, aStatus);

  // Note that this frame is a child of the viewport frame.
  WritingMode wm = aReflowInput.GetWritingMode();
  LogicalMargin borderPadding = aReflowInput.ComputedLogicalBorderPadding();
  nscoord isize = aReflowInput.ComputedISize() + borderPadding.IStartEnd(wm);
  nscoord bsize = aReflowInput.ComputedBSize() + borderPadding.BStartEnd(wm);
  aDesiredSize.SetSize(wm, LogicalSize(wm, isize, bsize));
  aStatus = NS_FRAME_COMPLETE;
}

/* 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);
//.........这里部分代码省略.........