C++ nsHTMLReflowMetrics::SetOverflowAreasToDesiredBounds方法代码示例

//.........这里部分代码省略.........
            kidReflowState.SetComputedHeight(
                std::max(0, aReflowState.ComputedHeight() - mLegendSpace));
        }

        if (aReflowState.ComputedMinHeight() > 0) {
            kidReflowState.ComputedMinHeight() =
                std::max(0, aReflowState.ComputedMinHeight() - mLegendSpace);
        }

        if (aReflowState.ComputedMaxHeight() != NS_UNCONSTRAINEDSIZE) {
            kidReflowState.ComputedMaxHeight() =
                std::max(0, aReflowState.ComputedMaxHeight() - mLegendSpace);
        }

        nsHTMLReflowMetrics kidDesiredSize(kidReflowState,
                                           aDesiredSize.mFlags);
        // Reflow the frame
        NS_ASSERTION(kidReflowState.ComputedPhysicalMargin() == nsMargin(0,0,0,0),
                     "Margins on anonymous fieldset child not supported!");
        nsPoint pt(border.left, border.top + mLegendSpace);
        ReflowChild(inner, aPresContext, kidDesiredSize, kidReflowState,
                    pt.x, pt.y, 0, aStatus);

        FinishReflowChild(inner, aPresContext, kidDesiredSize,
                          &kidReflowState, pt.x, pt.y, 0);
        NS_FRAME_TRACE_REFLOW_OUT("FieldSet::Reflow", aStatus);
    }

    nsRect contentRect;
    if (inner) {
        // We don't support margins on inner, so our content rect is just the
        // inner's border-box.
        contentRect = inner->GetRect();
    }

    // Our content rect must fill up the available width
    if (availSize.width > contentRect.width) {
        contentRect.width = availSize.width;
    }

    if (legend) {
        // the legend is postioned horizontally within the inner's content rect
        // (so that padding on the fieldset affects the legend position).
        nsRect innerContentRect = contentRect;
        innerContentRect.Deflate(aReflowState.ComputedPhysicalPadding());
        // if the inner content rect is larger than the legend, we can align the legend
        if (innerContentRect.width > mLegendRect.width) {
            int32_t align = static_cast<nsLegendFrame*>
                            (legend->GetContentInsertionFrame())->GetAlign();

            switch (align) {
            case NS_STYLE_TEXT_ALIGN_RIGHT:
                mLegendRect.x = innerContentRect.XMost() - mLegendRect.width;
                break;
            case NS_STYLE_TEXT_ALIGN_CENTER:
                // Note: rounding removed; there doesn't seem to be any need
                mLegendRect.x = innerContentRect.width / 2 - mLegendRect.width / 2 + innerContentRect.x;
                break;
            default:
                mLegendRect.x = innerContentRect.x;
                break;
            }
        } else {
            // otherwise make place for the legend
            mLegendRect.x = innerContentRect.x;
            innerContentRect.width = mLegendRect.width;
            contentRect.width = mLegendRect.width + aReflowState.ComputedPhysicalPadding().LeftRight();
        }

        // place the legend
        nsRect actualLegendRect(mLegendRect);
        actualLegendRect.Deflate(legendMargin);
        nsPoint actualLegendPos(actualLegendRect.TopLeft());
        legendReflowState.ref().ApplyRelativePositioning(&actualLegendPos);
        legend->SetPosition(actualLegendPos);
        nsContainerFrame::PositionFrameView(legend);
        nsContainerFrame::PositionChildViews(legend);
    }

    // Return our size and our result.
    aDesiredSize.Height() = mLegendSpace + border.TopBottom() +
                            (inner ? inner->GetRect().height : 0);
    aDesiredSize.Width() = contentRect.width + border.LeftRight();
    aDesiredSize.SetOverflowAreasToDesiredBounds();
    if (legend)
        ConsiderChildOverflow(aDesiredSize.mOverflowAreas, legend);
    if (inner)
        ConsiderChildOverflow(aDesiredSize.mOverflowAreas, inner);

    // Merge overflow container bounds and status.
    aDesiredSize.mOverflowAreas.UnionWith(ocBounds);
    NS_MergeReflowStatusInto(&aStatus, ocStatus);

    FinishReflowWithAbsoluteFrames(aPresContext, aDesiredSize, aReflowState, aStatus);

    InvalidateFrame();

    NS_FRAME_SET_TRUNCATION(aStatus, aReflowState, aDesiredSize);
    return NS_OK;
}

void
BRFrame::Reflow(nsPresContext* aPresContext,
                nsHTMLReflowMetrics& aMetrics,
                const nsHTMLReflowState& aReflowState,
                nsReflowStatus& aStatus)
{
  MarkInReflow();
  DO_GLOBAL_REFLOW_COUNT("BRFrame");
  DISPLAY_REFLOW(aPresContext, this, aReflowState, aMetrics, aStatus);
  WritingMode wm = aReflowState.GetWritingMode();
  LogicalSize finalSize(wm);
  finalSize.BSize(wm) = 0; // BR frames with block size 0 are ignored in quirks
                           // mode by nsLineLayout::VerticalAlignFrames .
                           // However, it's not always 0.  See below.
  finalSize.ISize(wm) = 0;
  aMetrics.SetBlockStartAscent(0);

  // Only when the BR is operating in a line-layout situation will it
  // behave like a BR. Additionally, we suppress breaks from BR inside
  // of ruby frames. To determine if we're inside ruby, we have to rely
  // on the *parent's* ShouldSuppressLineBreak() method, instead of our
  // own, because we may have custom "display" value that makes our
  // ShouldSuppressLineBreak() return false.
  nsLineLayout* ll = aReflowState.mLineLayout;
  if (ll && !GetParent()->StyleContext()->ShouldSuppressLineBreak()) {
    // Note that the compatibility mode check excludes AlmostStandards
    // mode, since this is the inline box model.  See bug 161691.
    if ( ll->LineIsEmpty() ||
         aPresContext->CompatibilityMode() == eCompatibility_FullStandards ) {
      // The line is logically empty; any whitespace is trimmed away.
      //
      // If this frame is going to terminate the line we know
      // that nothing else will go on the line. Therefore, in this
      // case, we provide some height for the BR frame so that it
      // creates some vertical whitespace.  It's necessary to use the
      // line-height rather than the font size because the
      // quirks-mode fix that doesn't apply the block's min
      // line-height makes this necessary to make BR cause a line
      // of the full line-height

      // We also do this in strict mode because BR should act like a
      // normal inline frame.  That line-height is used is important
      // here for cases where the line-height is less than 1.
      nsRefPtr<nsFontMetrics> fm;
      nsLayoutUtils::GetFontMetricsForFrame(this, getter_AddRefs(fm),
        nsLayoutUtils::FontSizeInflationFor(this));
      if (fm) {
        nscoord logicalHeight = aReflowState.CalcLineHeight();
        finalSize.BSize(wm) = logicalHeight;
        aMetrics.SetBlockStartAscent(nsLayoutUtils::GetCenteredFontBaseline(
                                       fm, logicalHeight, wm.IsLineInverted()));
      }
      else {
        aMetrics.SetBlockStartAscent(aMetrics.BSize(wm) = 0);
      }

      // XXX temporary until I figure out a better solution; see the
      // code in nsLineLayout::VerticalAlignFrames that zaps minY/maxY
      // if the width is zero.
      // XXX This also fixes bug 10036!
      // Warning: nsTextControlFrame::CalculateSizeStandard depends on
      // the following line, see bug 228752.
      finalSize.ISize(wm) = 1;
    }

    // Return our reflow status
    uint32_t breakType = aReflowState.mStyleDisplay->mBreakType;
    if (NS_STYLE_CLEAR_NONE == breakType) {
      breakType = NS_STYLE_CLEAR_LINE;
    }

    aStatus = NS_INLINE_BREAK | NS_INLINE_BREAK_AFTER |
      NS_INLINE_MAKE_BREAK_TYPE(breakType);
    ll->SetLineEndsInBR(true);
  }
  else {
    aStatus = NS_FRAME_COMPLETE;
  }

  aMetrics.SetSize(wm, finalSize);
  aMetrics.SetOverflowAreasToDesiredBounds();

  mAscent = aMetrics.BlockStartAscent();

  NS_FRAME_SET_TRUNCATION(aStatus, aReflowState, aMetrics);
}

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

  // Initialize OUT parameters
  aStatus = NS_FRAME_COMPLETE;

  // Because |Reflow| sets mComputedHeight on the child to
  // availableHeight.
  AddStateBits(NS_FRAME_CONTAINS_RELATIVE_HEIGHT);

  // Set our size up front, since some parts of reflow depend on it
  // being already set.  Note that the computed height may be
  // unconstrained; that's ok.  Consumers should watch out for that.
  SetSize(nsSize(aReflowState.ComputedWidth(), aReflowState.ComputedHeight()));
 
  // Reflow the main content first so that the placeholders of the
  // fixed-position frames will be in the right places on an initial
  // reflow.
  nscoord kidHeight = 0;

  nsresult rv = NS_OK;
  
  if (mFrames.NotEmpty()) {
    // Deal with a non-incremental reflow or an incremental reflow
    // targeted at our one-and-only principal child frame.
    if (aReflowState.ShouldReflowAllKids() ||
        aReflowState.mFlags.mVResize ||
        NS_SUBTREE_DIRTY(mFrames.FirstChild())) {
      // Reflow our one-and-only principal child frame
      nsIFrame*           kidFrame = mFrames.FirstChild();
      nsHTMLReflowMetrics kidDesiredSize(aReflowState);
      nsSize              availableSpace(aReflowState.AvailableWidth(),
                                         aReflowState.AvailableHeight());
      nsHTMLReflowState   kidReflowState(aPresContext, aReflowState,
                                         kidFrame, availableSpace);

      // Reflow the frame
      kidReflowState.SetComputedHeight(aReflowState.ComputedHeight());
      rv = ReflowChild(kidFrame, aPresContext, kidDesiredSize, kidReflowState,
                       0, 0, 0, aStatus);
      kidHeight = kidDesiredSize.Height();

      FinishReflowChild(kidFrame, aPresContext, kidDesiredSize, nullptr, 0, 0, 0);
    } else {
      kidHeight = mFrames.FirstChild()->GetSize().height;
    }
  }

  NS_ASSERTION(aReflowState.AvailableWidth() != NS_UNCONSTRAINEDSIZE,
               "shouldn't happen anymore");

  // Return the max size as our desired size
  aDesiredSize.Width() = aReflowState.AvailableWidth();
  // Being flowed initially at an unconstrained height means we should
  // return our child's intrinsic size.
  aDesiredSize.Height() = aReflowState.ComputedHeight() != NS_UNCONSTRAINEDSIZE
                          ? aReflowState.ComputedHeight()
                          : kidHeight;
  aDesiredSize.SetOverflowAreasToDesiredBounds();

  if (mFrames.NotEmpty()) {
    ConsiderChildOverflow(aDesiredSize.mOverflowAreas, mFrames.FirstChild());
  }

  if (IsAbsoluteContainer()) {
    // Make a copy of the reflow state and change the computed width and height
    // to reflect the available space for the fixed items
    nsHTMLReflowState reflowState(aReflowState);

    if (reflowState.AvailableHeight() == NS_UNCONSTRAINEDSIZE) {
      // We have an intrinsic-height document with abs-pos/fixed-pos children.
      // Set the available height and mComputedHeight to our chosen height.
      reflowState.AvailableHeight() = aDesiredSize.Height();
      // Not having border/padding simplifies things
      NS_ASSERTION(reflowState.ComputedPhysicalBorderPadding() == nsMargin(0,0,0,0),
                   "Viewports can't have border/padding");
      reflowState.SetComputedHeight(aDesiredSize.Height());
    }

    nsRect rect = AdjustReflowStateAsContainingBlock(&reflowState);

    // Just reflow all the fixed-pos frames.
    rv = GetAbsoluteContainingBlock()->Reflow(this, aPresContext, reflowState, aStatus,
                                              rect,
                                              false, true, true, // XXX could be optimized
                                              &aDesiredSize.mOverflowAreas);
  }

  // If we were dirty then do a repaint
  if (GetStateBits() & NS_FRAME_IS_DIRTY) {
    InvalidateFrame();
  }

//.........这里部分代码省略.........

NS_IMETHODIMP
nsVideoFrame::Reflow(nsPresContext*           aPresContext,
                     nsHTMLReflowMetrics&     aMetrics,
                     const nsHTMLReflowState& aReflowState,
                     nsReflowStatus&          aStatus)
{
  DO_GLOBAL_REFLOW_COUNT("nsVideoFrame");
  DISPLAY_REFLOW(aPresContext, this, aReflowState, aMetrics, aStatus);
  NS_FRAME_TRACE(NS_FRAME_TRACE_CALLS,
                  ("enter nsVideoFrame::Reflow: availSize=%d,%d",
                  aReflowState.availableWidth, aReflowState.availableHeight));

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

  aStatus = NS_FRAME_COMPLETE;

  aMetrics.width = aReflowState.ComputedWidth();
  aMetrics.height = aReflowState.ComputedHeight();

  // stash this away so we can compute our inner area later
  mBorderPadding   = aReflowState.mComputedBorderPadding;

  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.FirstChild();
       child;
       child = child->GetNextSibling()) {
    if (child->GetType() == nsGkAtoms::imageFrame) {
      // Reflow the poster frame.
      nsImageFrame* imageFrame = static_cast<nsImageFrame*>(child);
      nsHTMLReflowMetrics kidDesiredSize;
      nsSize availableSize = nsSize(aReflowState.availableWidth,
                                    aReflowState.availableHeight);
      nsHTMLReflowState kidReflowState(aPresContext,
                                       aReflowState,
                                       imageFrame,
                                       availableSize,
                                       aMetrics.width,
                                       aMetrics.height);

      uint32_t posterHeight, posterWidth;
      nsSize scaledPosterSize(0, 0);
      nsSize computedArea(aReflowState.ComputedWidth(), aReflowState.ComputedHeight());
      nsPoint posterTopLeft(0, 0);

      nsCOMPtr<nsIDOMHTMLImageElement> posterImage = do_QueryInterface(mPosterImage);
      NS_ENSURE_TRUE(posterImage, NS_ERROR_FAILURE);
      posterImage->GetNaturalHeight(&posterHeight);
      posterImage->GetNaturalWidth(&posterWidth);

      if (ShouldDisplayPoster() && posterHeight && posterWidth) {
        gfxFloat scale =
          NS_MIN(static_cast<float>(computedArea.width)/nsPresContext::CSSPixelsToAppUnits(static_cast<float>(posterWidth)),
                 static_cast<float>(computedArea.height)/nsPresContext::CSSPixelsToAppUnits(static_cast<float>(posterHeight)));
        gfxSize scaledRatio = gfxSize(scale*posterWidth, scale*posterHeight);
        scaledPosterSize.width = nsPresContext::CSSPixelsToAppUnits(static_cast<float>(scaledRatio.width));
        scaledPosterSize.height = nsPresContext::CSSPixelsToAppUnits(static_cast<int32_t>(scaledRatio.height));
      }
      kidReflowState.SetComputedWidth(scaledPosterSize.width);
      kidReflowState.SetComputedHeight(scaledPosterSize.height);
      posterTopLeft.x = ((computedArea.width - scaledPosterSize.width) / 2) + mBorderPadding.left;
      posterTopLeft.y = ((computedArea.height - scaledPosterSize.height) / 2) + mBorderPadding.top;

      ReflowChild(imageFrame, aPresContext, kidDesiredSize, kidReflowState,
                        posterTopLeft.x, posterTopLeft.y, 0, aStatus);
      FinishReflowChild(imageFrame, aPresContext, &kidReflowState, kidDesiredSize,
                        posterTopLeft.x, posterTopLeft.y, 0);
    } else if (child->GetType() == nsGkAtoms::boxFrame) {
      // Reflow the video controls frame.
      nsBoxLayoutState boxState(PresContext(), aReflowState.rendContext);
      nsBoxFrame::LayoutChildAt(boxState,
                                child,
                                nsRect(mBorderPadding.left,
                                       mBorderPadding.top,
                                       aReflowState.ComputedWidth(),
                                       aReflowState.ComputedHeight()));
    }
  }
  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, aReflowState, aMetrics);

  return NS_OK;
}

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

  NS_PRECONDITION(aReflowState.ComputedWidth() != NS_INTRINSICSIZE,
                  "Should have real computed width by now");

  if (mState & NS_FRAME_FIRST_REFLOW) {
    nsFormControlFrame::RegUnRegAccessKey(static_cast<nsIFrame*>(this), true);
  }

  // Reflow the child
  nsIFrame* firstKid = mFrames.FirstChild();

  // XXXbz Eventually we may want to check-and-bail if
  // !aReflowState.ShouldReflowAllKids() &&
  // !NS_SUBTREE_DIRTY(firstKid).
  // We'd need to cache our ascent for that, of course.
  
  nsMargin focusPadding = mRenderer.GetAddedButtonBorderAndPadding();
  
  // Reflow the contents of the button.
  ReflowButtonContents(aPresContext, aDesiredSize, aReflowState, firstKid,
                       focusPadding, aStatus);

  aDesiredSize.width = aReflowState.ComputedWidth();

  // If computed use the computed value.
  if (aReflowState.ComputedHeight() != NS_INTRINSICSIZE) {
    aDesiredSize.height = aReflowState.ComputedHeight();
  } else {
    aDesiredSize.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
    // aReflowState.ComputedHeight()).  Note that we do this before adjusting
    // for borderpadding, since mComputedMaxHeight and mComputedMinHeight are
    // content heights.
    aDesiredSize.height = NS_CSS_MINMAX(aDesiredSize.height,
                                        aReflowState.mComputedMinHeight,
                                        aReflowState.mComputedMaxHeight);
  }

  aDesiredSize.width += aReflowState.mComputedBorderPadding.LeftRight();
  aDesiredSize.height += aReflowState.mComputedBorderPadding.TopBottom();

  aDesiredSize.ascent +=
    aReflowState.mComputedBorderPadding.top + focusPadding.top;

  aDesiredSize.SetOverflowAreasToDesiredBounds();
  ConsiderChildOverflow(aDesiredSize.mOverflowAreas, firstKid);
  FinishReflowWithAbsoluteFrames(aPresContext, aDesiredSize, aReflowState, aStatus);

  aStatus = NS_FRAME_COMPLETE;

  NS_FRAME_SET_TRUNCATION(aStatus, aReflowState, aDesiredSize);
  return NS_OK;
}

//.........这里部分代码省略.........
    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,
                              aReflowState.ComputedMinBSize(),
                              aReflowState.ComputedMaxBSize());

            borderBoxBSize = contentBoxBSize +
                             aReflowState.ComputedLogicalBorderPadding().BStartEnd(myWM);
        }

        // Center child in block axis
        nscoord extraSpace = contentBoxBSize - wrappersMarginBoxBSize;
        wrapperOffset.B(myWM) += std::max(0, extraSpace / 2);

        // Needed in FinishReflowChild, for logical-to-physical conversion:
        nsSize borderBoxSize = LogicalSize(myWM, borderBoxISize, borderBoxBSize).
                               GetPhysicalSize(myWM);

        // Place the child
        FinishReflowChild(outerWrapperFrame, aPresContext, wrappersDesiredSize,
                          &wrapperReflowState, myWM, wrapperOffset,
                          borderBoxSize, 0);

        nsSize contentBoxSize =
            LogicalSize(myWM, contentBoxISize, contentBoxBSize).
            GetPhysicalSize(myWM);
        aDesiredSize.SetBlockStartAscent(
            wrappersDesiredSize.BlockStartAscent() +
            outerWrapperFrame->BStart(aReflowState.GetWritingMode(),
                                      contentBoxSize));
    }

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

    aDesiredSize.SetOverflowAreasToDesiredBounds();

    if (outerWrapperFrame) {
        ConsiderChildOverflow(aDesiredSize.mOverflowAreas, outerWrapperFrame);
    }

    FinishAndStoreOverflow(&aDesiredSize);

    aStatus = NS_FRAME_COMPLETE;

    NS_FRAME_SET_TRUNCATION(aStatus, aReflowState, aDesiredSize);
}

void
nsSimplePageSequenceFrame::Reflow(nsPresContext*          aPresContext,
                                  nsHTMLReflowMetrics&     aDesiredSize,
                                  const nsHTMLReflowState& aReflowState,
                                  nsReflowStatus&          aStatus)
{
  NS_PRECONDITION(aPresContext->IsRootPaginatedDocument(),
                  "A Page Sequence is only for real pages");
  DO_GLOBAL_REFLOW_COUNT("nsSimplePageSequenceFrame");
  DISPLAY_REFLOW(aPresContext, this, aReflowState, aDesiredSize, aStatus);
  NS_FRAME_TRACE_REFLOW_IN("nsSimplePageSequenceFrame::Reflow");

  aStatus = NS_FRAME_COMPLETE;  // we're always complete

  // Don't do incremental reflow until we've taught tables how to do
  // it right in paginated mode.
  if (!(GetStateBits() & NS_FRAME_FIRST_REFLOW)) {
    // Return our desired size
    SetDesiredSize(aDesiredSize, aReflowState, mSize.width, mSize.height);
    aDesiredSize.SetOverflowAreasToDesiredBounds();
    FinishAndStoreOverflow(&aDesiredSize);
    return;
  }

  // See if we can get a Print Settings from the Context
  if (!mPageData->mPrintSettings &&
      aPresContext->Medium() == nsGkAtoms::print) {
      mPageData->mPrintSettings = aPresContext->GetPrintSettings();
  }

  // now get out margins & edges
  if (mPageData->mPrintSettings) {
    nsIntMargin unwriteableTwips;
    mPageData->mPrintSettings->GetUnwriteableMarginInTwips(unwriteableTwips);
    NS_ASSERTION(unwriteableTwips.left  >= 0 && unwriteableTwips.top >= 0 &&
                 unwriteableTwips.right >= 0 && unwriteableTwips.bottom >= 0,
                 "Unwriteable twips should be non-negative");

    nsIntMargin marginTwips;
    mPageData->mPrintSettings->GetMarginInTwips(marginTwips);
    mMargin = aPresContext->CSSTwipsToAppUnits(marginTwips + unwriteableTwips);

    int16_t printType;
    mPageData->mPrintSettings->GetPrintRange(&printType);
    mPrintRangeType = printType;

    nsIntMargin edgeTwips;
    mPageData->mPrintSettings->GetEdgeInTwips(edgeTwips);

    // sanity check the values. three inches are sometimes needed
    int32_t inchInTwips = NS_INCHES_TO_INT_TWIPS(3.0);
    edgeTwips.top    = clamped(edgeTwips.top,    0, inchInTwips);
    edgeTwips.bottom = clamped(edgeTwips.bottom, 0, inchInTwips);
    edgeTwips.left   = clamped(edgeTwips.left,   0, inchInTwips);
    edgeTwips.right  = clamped(edgeTwips.right,  0, inchInTwips);

    mPageData->mEdgePaperMargin =
      aPresContext->CSSTwipsToAppUnits(edgeTwips + unwriteableTwips);
  }

  // *** Special Override ***
  // If this is a sub-sdoc (meaning it doesn't take the whole page)
  // and if this Document is in the upper left hand corner
  // we need to suppress the top margin or it will reflow too small

  nsSize pageSize = aPresContext->GetPageSize();

  mPageData->mReflowSize = pageSize;
  // If we're printing a selection, we need to reflow with
  // unconstrained height, to make sure we'll get to the selection
  // even if it's beyond the first page of content.
  if (nsIPrintSettings::kRangeSelection == mPrintRangeType) {
    mPageData->mReflowSize.height = NS_UNCONSTRAINEDSIZE;
  }
  mPageData->mReflowMargin = mMargin;

  // We use the CSS "margin" property on the -moz-page pseudoelement
  // to determine the space between each page in print preview.
  // Keep a running y-offset for each page.
  nscoord y = 0;
  nscoord maxXMost = 0;

  // Tile the pages vertically
  nsHTMLReflowMetrics kidSize(aReflowState);
  for (nsFrameList::Enumerator e(mFrames); !e.AtEnd(); e.Next()) {
    nsIFrame* kidFrame = e.get();
    // Set the shared data into the page frame before reflow
    nsPageFrame * pf = static_cast<nsPageFrame*>(kidFrame);
    pf->SetSharedPageData(mPageData);

    // Reflow the page
    nsHTMLReflowState kidReflowState(aPresContext, aReflowState, kidFrame,
                                     LogicalSize(kidFrame->GetWritingMode(),
                                                 pageSize));
    nsReflowStatus  status;

    kidReflowState.SetComputedWidth(kidReflowState.AvailableWidth());
    //kidReflowState.SetComputedHeight(kidReflowState.AvailableHeight());
    PR_PL(("AV W: %d   H: %d\n", kidReflowState.AvailableWidth(), kidReflowState.AvailableHeight()));

//.........这里部分代码省略.........

//.........这里部分代码省略.........

        // 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);

    // Place the child
    FinishReflowChild(aFirstKid, aPresContext,
                      contentsDesiredSize, &contentsReflowState,
                      isVertical ? boffset : ioffset,
                      isVertical ? ioffset : boffset,
                      0);

    // Make sure we have a useful 'ascent' value for the child
    if (contentsDesiredSize.BlockStartAscent() ==
            nsHTMLReflowMetrics::ASK_FOR_BASELINE) {
        WritingMode wm = aButtonReflowState.GetWritingMode();
        contentsDesiredSize.SetBlockStartAscent(aFirstKid->GetLogicalBaseline(wm));
    }

    // OK, we're done with the child frame.
    // Use what we learned to populate the button frame's reflow metrics.
    //  * Button's height & width are content-box size + border-box contribution:
    aButtonDesiredSize.SetSize(wm,
                               LogicalSize(wm, aButtonReflowState.ComputedISize() + clbp.IStartEnd(wm),
                                           buttonContentBoxBSize + clbp.BStartEnd(wm)));

    //  * Button's ascent is its child's ascent, plus the child's block-offset
    // within our frame... unless it's orthogonal, in which case we'll use the
    // contents inline-size as an approximation for now.
    // XXX is there a better strategy? should we include border-padding?
    if (aButtonDesiredSize.GetWritingMode().IsOrthogonalTo(wm)) {
        aButtonDesiredSize.SetBlockStartAscent(contentsDesiredSize.ISize(wm));
    } else {
        aButtonDesiredSize.SetBlockStartAscent(contentsDesiredSize.BlockStartAscent() +
                                               boffset);
    }

    aButtonDesiredSize.SetOverflowAreasToDesiredBounds();
}

void
nsVideoFrame::Reflow(nsPresContext*           aPresContext,
                     nsHTMLReflowMetrics&     aMetrics,
                     const nsHTMLReflowState& aReflowState,
                     nsReflowStatus&          aStatus)
{
  MarkInReflow();
  DO_GLOBAL_REFLOW_COUNT("nsVideoFrame");
  DISPLAY_REFLOW(aPresContext, this, aReflowState, aMetrics, aStatus);
  NS_FRAME_TRACE(NS_FRAME_TRACE_CALLS,
                  ("enter nsVideoFrame::Reflow: availSize=%d,%d",
                  aReflowState.AvailableWidth(), aReflowState.AvailableHeight()));

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

  aStatus = NS_FRAME_COMPLETE;

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

  // stash this away so we can compute our inner area later
  mBorderPadding   = aReflowState.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);
      nsHTMLReflowMetrics kidDesiredSize(aReflowState);
      WritingMode wm = imageFrame->GetWritingMode();
      LogicalSize availableSize = aReflowState.AvailableSize(wm);
      LogicalSize cbSize = aMetrics.Size(aMetrics.GetWritingMode()).
                             ConvertTo(wm, aMetrics.GetWritingMode());
      nsHTMLReflowState kidReflowState(aPresContext,
                                       aReflowState,
                                       imageFrame,
                                       availableSize,
                                       &cbSize);

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

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

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

  FinishAndStoreOverflow(&aMetrics);
//.........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.........

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

  // Initialize OUT parameters
  aStatus = NS_FRAME_COMPLETE;

  // Because |Reflow| sets mComputedHeight on the child to
  // availableHeight.
  AddStateBits(NS_FRAME_CONTAINS_RELATIVE_HEIGHT);

  // Set our size up front, since some parts of reflow depend on it
  // being already set.  Note that the computed height may be
  // unconstrained; that's ok.  Consumers should watch out for that.
  SetSize(nsSize(aReflowState.ComputedWidth(), aReflowState.ComputedHeight()));
 
  // Reflow the main content first so that the placeholders of the
  // fixed-position frames will be in the right places on an initial
  // reflow.
  nscoord kidHeight = 0;

  nsresult rv = NS_OK;
  
  if (mFrames.NotEmpty()) {
    // Deal with a non-incremental reflow or an incremental reflow
    // targeted at our one-and-only principal child frame.
    if (aReflowState.ShouldReflowAllKids() ||
        aReflowState.mFlags.mVResize ||
        NS_SUBTREE_DIRTY(mFrames.FirstChild())) {
      // Reflow our one-and-only principal child frame
      nsIFrame*           kidFrame = mFrames.FirstChild();
      nsHTMLReflowMetrics kidDesiredSize;
      nsSize              availableSpace(aReflowState.availableWidth,
                                         aReflowState.availableHeight);
      nsHTMLReflowState   kidReflowState(aPresContext, aReflowState,
                                         kidFrame, availableSpace);

      // Reflow the frame
      kidReflowState.SetComputedHeight(aReflowState.ComputedHeight());
      rv = ReflowChild(kidFrame, aPresContext, kidDesiredSize, kidReflowState,
                       0, 0, 0, aStatus);
      kidHeight = kidDesiredSize.height;

      FinishReflowChild(kidFrame, aPresContext, nsnull, kidDesiredSize, 0, 0, 0);
    } else {
      kidHeight = mFrames.FirstChild()->GetSize().height;
    }
  }

  NS_ASSERTION(aReflowState.availableWidth != NS_UNCONSTRAINEDSIZE,
               "shouldn't happen anymore");

  // Return the max size as our desired size
  aDesiredSize.width = aReflowState.availableWidth;
  // Being flowed initially at an unconstrained height means we should
  // return our child's intrinsic size.
  aDesiredSize.height = aReflowState.ComputedHeight() != NS_UNCONSTRAINEDSIZE
                          ? aReflowState.ComputedHeight()
                          : kidHeight;

  // Make a copy of the reflow state and change the computed width and height
  // to reflect the available space for the fixed items
  nsHTMLReflowState reflowState(aReflowState);
  nsPoint offset = AdjustReflowStateForScrollbars(&reflowState);
  
#ifdef DEBUG
  NS_ASSERTION(mFixedContainer.GetChildList().IsEmpty() ||
               (offset.x == 0 && offset.y == 0),
               "We don't handle correct positioning of fixed frames with "
               "scrollbars in odd positions");
#endif

  // Just reflow all the fixed-pos frames.
  rv = mFixedContainer.Reflow(this, aPresContext, reflowState, aStatus,
                              reflowState.ComputedWidth(),
                              reflowState.ComputedHeight(),
                              PR_FALSE, PR_TRUE, PR_TRUE, // XXX could be optimized
                              nsnull /* ignore overflow */);

  // If we were dirty then do a repaint
  if (GetStateBits() & NS_FRAME_IS_DIRTY) {
    nsRect damageRect(0, 0, aDesiredSize.width, aDesiredSize.height);
    Invalidate(damageRect);
  }

  // XXX Should we do something to clip our children to this?
  aDesiredSize.SetOverflowAreasToDesiredBounds();

  NS_FRAME_TRACE_REFLOW_OUT("ViewportFrame::Reflow", aStatus);
  NS_FRAME_SET_TRUNCATION(aStatus, aReflowState, aDesiredSize);
  return rv; 
}

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

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

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

  if (mInnerView) {
    const nsMargin& bp = aReflowState.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, aReflowState, aDesiredSize);
}

NS_IMETHODIMP
nsVideoFrame::Reflow(nsPresContext*           aPresContext,
                     nsHTMLReflowMetrics&     aMetrics,
                     const nsHTMLReflowState& aReflowState,
                     nsReflowStatus&          aStatus)
{
  DO_GLOBAL_REFLOW_COUNT("nsVideoFrame");
  DISPLAY_REFLOW(aPresContext, this, aReflowState, aMetrics, aStatus);
  NS_FRAME_TRACE(NS_FRAME_TRACE_CALLS,
                  ("enter nsVideoFrame::Reflow: availSize=%d,%d",
                  aReflowState.availableWidth, aReflowState.availableHeight));

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

  aStatus = NS_FRAME_COMPLETE;

  aMetrics.width = aReflowState.ComputedWidth();
  aMetrics.height = aReflowState.ComputedHeight();

  // stash this away so we can compute our inner area later
  mBorderPadding   = aReflowState.mComputedBorderPadding;

  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.FirstChild();
       child;
       child = child->GetNextSibling()) {
    if (child->GetType() == nsGkAtoms::imageFrame) {
      // Reflow the poster frame.
      nsImageFrame* imageFrame = static_cast<nsImageFrame*>(child);
      nsHTMLReflowMetrics kidDesiredSize;
      nsSize availableSize = nsSize(aReflowState.availableWidth,
                                    aReflowState.availableHeight);
      nsHTMLReflowState kidReflowState(aPresContext,
                                       aReflowState,
                                       imageFrame,
                                       availableSize,
                                       aMetrics.width,
                                       aMetrics.height);
      if (ShouldDisplayPoster()) {
        kidReflowState.SetComputedWidth(aReflowState.ComputedWidth());
        kidReflowState.SetComputedHeight(aReflowState.ComputedHeight());
      } else {
        kidReflowState.SetComputedWidth(0);
        kidReflowState.SetComputedHeight(0);
      }
      ReflowChild(imageFrame, aPresContext, kidDesiredSize, kidReflowState,
                  mBorderPadding.left, mBorderPadding.top, 0, aStatus);
      FinishReflowChild(imageFrame, aPresContext,
                        &kidReflowState, kidDesiredSize,
                        mBorderPadding.left, mBorderPadding.top, 0);
    } else if (child->GetType() == nsGkAtoms::boxFrame) {
      // Reflow the video controls frame.
      nsBoxLayoutState boxState(PresContext(), aReflowState.rendContext);
      nsBoxFrame::LayoutChildAt(boxState,
                                child,
                                nsRect(mBorderPadding.left,
                                       mBorderPadding.top,
                                       aReflowState.ComputedWidth(),
                                       aReflowState.ComputedHeight()));
    }
  }
  aMetrics.SetOverflowAreasToDesiredBounds();

  FinishAndStoreOverflow(&aMetrics);

  if (mRect.width != aMetrics.width || mRect.height != aMetrics.height) {
    Invalidate(nsRect(0, 0, mRect.width, mRect.height));
  }

  NS_FRAME_TRACE(NS_FRAME_TRACE_CALLS,
                  ("exit nsVideoFrame::Reflow: size=%d,%d",
                  aMetrics.width, aMetrics.height));
  NS_FRAME_SET_TRUNCATION(aStatus, aReflowState, aMetrics);

  return NS_OK;
}

//.........这里部分代码省略.........
    // 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 = GetFirstPrincipalChild();
      anonChild->AddStateBits(NS_FRAME_IS_DIRTY);
      for (nsIFrame* child = anonChild->GetFirstPrincipalChild(); child;
           child = child->GetNextSibling()) {
        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();
    NS_ABORT_IF_FALSE(!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, aReflowState, aDesiredSize);
}

//.........这里部分代码省略.........
  // 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 = GetMinWidth(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 += extraleft + extraright;
  }
  availSize.width = std::max(availSize.width,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.GetWritingMode());
  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.TopAscent() == nsHTMLReflowMetrics::ASK_FOR_BASELINE) {
    contentsDesiredSize.SetTopAscent(aFirstKid->GetBaseline());
  }

  // OK, we're done with the child frame.
  // Use what we learned to populate the button frame's reflow metrics.
  //  * Button's height & width are content-box size + border-box contribution:
  aButtonDesiredSize.Width() = aButtonReflowState.ComputedWidth() +
    aButtonReflowState.ComputedPhysicalBorderPadding().LeftRight();

  aButtonDesiredSize.Height() = buttonContentBoxHeight +
    aButtonReflowState.ComputedPhysicalBorderPadding().TopBottom();

  //  * Button's ascent is its child's ascent, plus the child's y-offset
  // within our frame:
  aButtonDesiredSize.SetTopAscent(contentsDesiredSize.TopAscent() + yoffset);

  aButtonDesiredSize.SetOverflowAreasToDesiredBounds();
}