nsIFrame*
nsFieldSetFrame::MaybeSetLegend(nsIFrame* aFrameList, nsIAtom* aListName)
{
  if (!mLegendFrame && aFrameList->GetType() == nsLayoutAtoms::legendFrame) {
    NS_ASSERTION(!aListName, "Unexpected frame list when adding legend frame");
    mLegendFrame = aFrameList;
    aFrameList = mLegendFrame->GetNextSibling();
    mLegendFrame->SetNextSibling(mContentFrame);
    mFrames.SetFrames(mLegendFrame);
    AddStateBits(NS_FRAME_IS_DIRTY);
    if (GetParent()) {
      GetParent()->ReflowDirtyChild(mLegendFrame->GetPresContext()->GetPresShell(), this);
    }
  }
  return aFrameList;
}

void
nsFieldSetFrame::ReParentFrameList(nsIFrame* aFrameList)
{
  nsFrameManager* frameManager = GetPresContext()->FrameManager();
  for (nsIFrame* frame = aFrameList; frame; frame = frame->GetNextSibling()) {
    frame->SetParent(mContentFrame);
    frameManager->ReParentStyleContext(frame);
  }
  mContentFrame->AddStateBits(GetStateBits() & NS_FRAME_HAS_CHILD_WITH_VIEW);
}

NS_IMETHODIMP
nsFieldSetFrame::ReplaceFrame(nsIAtom*       aListName,
                              nsIFrame*      aOldFrame,
                              nsIFrame*      aNewFrame)
{
  if (aOldFrame == mLegendFrame) {
    mLegendFrame = aNewFrame;
    return nsContainerFrame::ReplaceFrame(aListName, aOldFrame, aNewFrame);
  }
  return mContentFrame->ReplaceFrame(aListName, aOldFrame, aNewFrame);
}

NS_IMETHODIMP
nsFieldSetFrame::AppendFrames(nsIAtom*       aListName,
                              nsIFrame*      aFrameList)
{
  aFrameList = MaybeSetLegend(aFrameList, aListName);
  if (aFrameList) {
    ReParentFrameList(aFrameList);
    return mContentFrame->AppendFrames(aListName, aFrameList);
  }
  return NS_OK;
}

nsresult
nsSplitterFrameInner::MouseDown(nsIDOMEvent* aMouseEvent)
{  
  NS_ENSURE_TRUE(mOuter, NS_OK);
  nsCOMPtr<nsIDOMMouseEvent> mouseEvent(do_QueryInterface(aMouseEvent));
  if (!mouseEvent)
    return NS_OK;

  PRUint16 button = 0;
  mouseEvent->GetButton(&button);

  // only if left button
  if (button != 0)
     return NS_OK;

  if (mOuter->GetContent()->
        AttrValueIs(kNameSpaceID_None, nsGkAtoms::disabled,
                    nsGkAtoms::_true, eCaseMatters))
    return NS_OK;

  mParentBox = mOuter->GetParentBox();
  if (!mParentBox)
    return NS_OK;

  // get our index
  nsPresContext* outerPresContext = mOuter->PresContext();
  const nsFrameList& siblingList(mParentBox->PrincipalChildList());
  PRInt32 childIndex = siblingList.IndexOf(mOuter);
  // if it's 0 (or not found) then stop right here.
  // It might be not found if we're not in the parent's primary frame list.
  if (childIndex <= 0)
    return NS_OK;

  PRInt32 childCount = siblingList.GetLength();
  // if it's the last index then we need to allow for resizeafter="grow"
  if (childIndex == childCount - 1 && GetResizeAfter() != Grow)
    return NS_OK;

  nsRefPtr<nsRenderingContext> rc =
    outerPresContext->PresShell()->GetReferenceRenderingContext();
  NS_ENSURE_TRUE(rc, NS_ERROR_FAILURE);
  nsBoxLayoutState state(outerPresContext, rc);
  mCurrentPos = 0;
  mPressed = true;

  mDidDrag = false;

  EnsureOrient();
  bool isHorizontal = !mOuter->IsHorizontal();
  
  ResizeType resizeBefore = GetResizeBefore();
  ResizeType resizeAfter  = GetResizeAfter();

  delete[] mChildInfosBefore;
  delete[] mChildInfosAfter;
  mChildInfosBefore = new nsSplitterInfo[childCount];
  mChildInfosAfter  = new nsSplitterInfo[childCount];

  // create info 2 lists. One of the children before us and one after.
  PRInt32 count = 0;
  mChildInfosBeforeCount = 0;
  mChildInfosAfterCount = 0;

  nsIFrame* childBox = mParentBox->GetChildBox();

  while (nullptr != childBox) 
  { 
    nsIContent* content = childBox->GetContent();
    nsIDocument* doc = content->OwnerDoc();
    PRInt32 dummy;
    nsIAtom* atom = doc->BindingManager()->ResolveTag(content, &dummy);

    // skip over any splitters
    if (atom != nsGkAtoms::splitter) { 
        nsSize prefSize = childBox->GetPrefSize(state);
        nsSize minSize = childBox->GetMinSize(state);
        nsSize maxSize = nsBox::BoundsCheckMinMax(minSize, childBox->GetMaxSize(state));
        prefSize = nsBox::BoundsCheck(minSize, prefSize, maxSize);

        mOuter->AddMargin(childBox, minSize);
        mOuter->AddMargin(childBox, prefSize);
        mOuter->AddMargin(childBox, maxSize);

        nscoord flex = childBox->GetFlex(state);

        nsMargin margin(0,0,0,0);
        childBox->GetMargin(margin);
        nsRect r(childBox->GetRect());
        r.Inflate(margin);

        // We need to check for hidden attribute too, since treecols with
        // the hidden="true" attribute are not really hidden, just collapsed
        if (!content->AttrValueIs(kNameSpaceID_None, nsGkAtoms::fixed,
                                  nsGkAtoms::_true, eCaseMatters) &&
            !content->AttrValueIs(kNameSpaceID_None, nsGkAtoms::hidden,
                                  nsGkAtoms::_true, eCaseMatters)) {
            if (count < childIndex && (resizeBefore != Flex || flex > 0)) {
                mChildInfosBefore[mChildInfosBeforeCount].childElem = content;
                mChildInfosBefore[mChildInfosBeforeCount].min     = isHorizontal ? minSize.width : minSize.height;
                mChildInfosBefore[mChildInfosBeforeCount].max     = isHorizontal ? maxSize.width : maxSize.height;
//.........这里部分代码省略.........

bool
PaintFrameCallback::operator()(gfxContext* aContext,
                               const gfxRect& aFillRect,
                               const Filter& aFilter,
                               const gfxMatrix& aTransform)
{
  if (mFrame->GetStateBits() & NS_FRAME_DRAWING_AS_PAINTSERVER)
    return false;

  mFrame->AddStateBits(NS_FRAME_DRAWING_AS_PAINTSERVER);

  aContext->Save();

  // Clip to aFillRect so that we don't paint outside.
  aContext->NewPath();
  aContext->Rectangle(aFillRect);
  aContext->Clip();

  gfxMatrix invmatrix = aTransform;
  if (!invmatrix.Invert()) {
    return false;
  }
  aContext->Multiply(invmatrix);

  // nsLayoutUtils::PaintFrame will anchor its painting at mFrame. But we want
  // to have it anchored at the top left corner of the bounding box of all of
  // mFrame's continuations. So we add a translation transform.
  int32_t appUnitsPerDevPixel = mFrame->PresContext()->AppUnitsPerDevPixel();
  nsPoint offset = GetOffsetToBoundingBox(mFrame);
  gfxPoint devPxOffset = gfxPoint(offset.x, offset.y) / appUnitsPerDevPixel;
  aContext->Multiply(gfxMatrix::Translation(devPxOffset));

  gfxSize paintServerSize =
    gfxSize(mPaintServerSize.width, mPaintServerSize.height) /
      mFrame->PresContext()->AppUnitsPerDevPixel();

  // nsLayoutUtils::PaintFrame wants to render with paintServerSize, but we
  // want it to render with mRenderSize, so we need to set up a scale transform.
  gfxFloat scaleX = mRenderSize.width / paintServerSize.width;
  gfxFloat scaleY = mRenderSize.height / paintServerSize.height;
  aContext->Multiply(gfxMatrix::Scaling(scaleX, scaleY));

  // Draw.
  nsRect dirty(-offset.x, -offset.y,
               mPaintServerSize.width, mPaintServerSize.height);

  uint32_t flags = nsLayoutUtils::PAINT_IN_TRANSFORM;
  if (mFlags & nsSVGIntegrationUtils::FLAG_SYNC_DECODE_IMAGES) {
    flags |= nsLayoutUtils::PAINT_SYNC_DECODE_IMAGES;
  }
  nsRenderingContext context(aContext);
  nsLayoutUtils::PaintFrame(&context, mFrame,
                            dirty, NS_RGBA(0, 0, 0, 0),
                            flags);

  nsIFrame* currentFrame = mFrame;
   while ((currentFrame = currentFrame->GetNextContinuation()) != nullptr) {
    offset = currentFrame->GetOffsetToCrossDoc(mFrame);
    devPxOffset = gfxPoint(offset.x, offset.y) / appUnitsPerDevPixel;

    aContext->Save();
    aContext->Multiply(gfxMatrix::Scaling(1/scaleX, 1/scaleY));
    aContext->Multiply(gfxMatrix::Translation(devPxOffset));
    aContext->Multiply(gfxMatrix::Scaling(scaleX, scaleY));

    nsLayoutUtils::PaintFrame(&context, currentFrame,
                              dirty - offset, NS_RGBA(0, 0, 0, 0),
                              flags);

    aContext->Restore();
  }

  aContext->Restore();

  mFrame->RemoveStateBits(NS_FRAME_DRAWING_AS_PAINTSERVER);

  return true;
}

void
nsSplitterFrameInner::EnsureOrient()
{
  bool isHorizontal = !(mParentBox->GetStateBits() & NS_STATE_IS_HORIZONTAL);
  if (isHorizontal)
    mOuter->mState |= NS_STATE_IS_HORIZONTAL;
  else
    mOuter->mState &= ~NS_STATE_IS_HORIZONTAL;
}

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

  // Initialize OUT parameter
  aStatus = NS_FRAME_COMPLETE;

  // Should we create a space manager?
  nsAutoSpaceManager autoSpaceManager(NS_CONST_CAST(nsHTMLReflowState &, aReflowState));

  // XXXldb If we start storing the space manager in the frame rather
  // than keeping it around only during reflow then we should create it
  // only when there are actually floats to manage.  Otherwise things
  // like tables will gain significant bloat.
  if (NS_BLOCK_SPACE_MGR & mState)
    autoSpaceManager.CreateSpaceManagerFor(aPresContext, this);

  
  //------------ Handle Incremental Reflow -----------------
  PRBool reflowContent = PR_TRUE;
  PRBool reflowLegend = PR_TRUE;
  nsReflowReason reason = aReflowState.reason;

  if (reason == eReflowReason_Incremental) {
      nsHTMLReflowCommand *command = aReflowState.path->mReflowCommand;

      // See if it's targeted at us
      if (command) {
        nsReflowType  reflowType;
        command->GetType(reflowType);

        switch (reflowType) {
          case eReflowType_StyleChanged:
            reason = eReflowReason_StyleChange;
            break;

          case eReflowType_ReflowDirty: 
            reason = eReflowReason_Dirty;
            break;

          default:
            NS_ERROR("Unexpected Reflow Type");
        }
      } else {
           reflowContent = PR_FALSE;
           reflowLegend = PR_FALSE;

           nsReflowPath::iterator iter = aReflowState.path->FirstChild();
           nsReflowPath::iterator end = aReflowState.path->EndChildren();

           for ( ; iter != end; ++iter) {
               if (*iter == mLegendFrame)
                   reflowLegend = PR_TRUE;
               else if (*iter == mContentFrame)
                   reflowContent = PR_TRUE;
           }
      }
  }

  if (aDesiredSize.mFlags & NS_REFLOW_CALC_MAX_WIDTH) {
    reflowLegend = PR_TRUE;
    reflowContent = PR_TRUE;
  } else if (reason == eReflowReason_Dirty) {
    // if dirty then check dirty flags
    if (GetStateBits() & NS_FRAME_IS_DIRTY) {
      reflowLegend = PR_TRUE;
      reflowContent = PR_TRUE;
    } else {
      if (reflowContent) {
        reflowContent = mContentFrame ?
          (mContentFrame->GetStateBits()
           & (NS_FRAME_IS_DIRTY | NS_FRAME_HAS_DIRTY_CHILDREN)) != 0 : PR_FALSE;
      }

      if (reflowLegend) {
        reflowLegend = mLegendFrame ?
          (mLegendFrame->GetStateBits()
           & (NS_FRAME_IS_DIRTY | NS_FRAME_HAS_DIRTY_CHILDREN)) != 0 : PR_FALSE;
      }
    }
  }

  // availSize could have unconstrained values, don't perform any addition on them
  nsSize availSize(aReflowState.mComputedWidth, aReflowState.availableHeight);

  // get our border and padding
  const nsMargin &borderPadding = aReflowState.mComputedBorderPadding;
  const nsMargin &padding       = aReflowState.mComputedPadding;
  nsMargin border = borderPadding - padding;
  if (aDesiredSize.mComputeMEW) {
    aDesiredSize.mMaxElementWidth = borderPadding.left + borderPadding.right;
  }
  

  // Figure out how big the legend is if there is one. 
//.........这里部分代码省略.........

// this is identical to nsHTMLContainerFrame::Paint except for the background and border. 
NS_IMETHODIMP
nsFieldSetFrame::Paint(nsPresContext*       aPresContext,
                       nsIRenderingContext& aRenderingContext,
                       const nsRect&        aDirtyRect,
                       nsFramePaintLayer    aWhichLayer,
                       PRUint32             aFlags)
{
  if (NS_FRAME_PAINT_LAYER_BACKGROUND == aWhichLayer) {
    // Paint our background and border
    PRBool isVisible;
    if (NS_SUCCEEDED(IsVisibleForPainting(aPresContext, aRenderingContext, PR_TRUE, &isVisible)) && 
                     isVisible && mRect.width && mRect.height) {
      PRIntn skipSides = GetSkipSides();
      const nsStyleBorder* borderStyle = GetStyleBorder();
      const nsStylePadding* paddingStyle = GetStylePadding();
       
      nscoord topBorder = borderStyle->GetBorderWidth(NS_SIDE_TOP);

      nscoord yoff = 0;
      
      // if the border is smaller than the legend. Move the border down
      // to be centered on the legend. 
      if (topBorder < mLegendRect.height)
        yoff = (mLegendRect.height - topBorder)/2;
      
      nsRect rect(0, yoff, mRect.width, mRect.height - yoff);

      nsCSSRendering::PaintBackground(aPresContext, aRenderingContext, this,
                                      aDirtyRect, rect, *borderStyle,
                                      *paddingStyle, PR_TRUE);

      if (mLegendFrame) {

        // Use the rect of the legend frame, not mLegendRect, so we draw our
        // border under the legend's left and right margins.
        const nsRect & legendRect = mLegendFrame->GetRect();
      
        // we should probably use PaintBorderEdges to do this but for now just use clipping
        // to achieve the same effect.

        // draw left side
        nsRect clipRect(rect);
        clipRect.width = legendRect.x - rect.x;
        clipRect.height = topBorder;

        aRenderingContext.PushState();
        aRenderingContext.SetClipRect(clipRect, nsClipCombine_kIntersect);
        nsCSSRendering::PaintBorder(aPresContext, aRenderingContext, this,
                                    aDirtyRect, rect, *borderStyle, mStyleContext, skipSides);
  
        aRenderingContext.PopState();


        // draw right side
        clipRect = rect;
        clipRect.x = legendRect.x + legendRect.width;
        clipRect.width -= (legendRect.x + legendRect.width);
        clipRect.height = topBorder;

        aRenderingContext.PushState();
        aRenderingContext.SetClipRect(clipRect, nsClipCombine_kIntersect);
        nsCSSRendering::PaintBorder(aPresContext, aRenderingContext, this,
                                    aDirtyRect, rect, *borderStyle, mStyleContext, skipSides);
  
        aRenderingContext.PopState();

      
        // draw bottom
        clipRect = rect;
        clipRect.y += topBorder;
        clipRect.height = mRect.height - (yoff + topBorder);
      
        aRenderingContext.PushState();
        aRenderingContext.SetClipRect(clipRect, nsClipCombine_kIntersect);
        nsCSSRendering::PaintBorder(aPresContext, aRenderingContext, this,
                                    aDirtyRect, rect, *borderStyle, mStyleContext, skipSides);
  
        aRenderingContext.PopState();
      } else {

        nsCSSRendering::PaintBorder(aPresContext, aRenderingContext, this,
                                    aDirtyRect,
                                    nsRect(0,0,mRect.width, mRect.height),
                                    *borderStyle, mStyleContext, skipSides);
      }
    }
  }

  PaintChildren(aPresContext, aRenderingContext, aDirtyRect, aWhichLayer);

#ifdef DEBUG
  if ((NS_FRAME_PAINT_LAYER_DEBUG == aWhichLayer) && GetShowFrameBorders()) {
    if (HasView()) {
      aRenderingContext.SetColor(NS_RGB(0,0,255));
    }
    else {
      aRenderingContext.SetColor(NS_RGB(255,0,0));
    }
    aRenderingContext.DrawRect(0, 0, mRect.width, mRect.height);
//.........这里部分代码省略.........