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

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

  // Initialize OUT parameter
  aStatus = NS_FRAME_COMPLETE;

  nsCanvasFrame* prevCanvasFrame = static_cast<nsCanvasFrame*>
                                               (GetPrevInFlow());
  if (prevCanvasFrame) {
    AutoFrameListPtr overflow(aPresContext,
                              prevCanvasFrame->StealOverflowFrames());
    if (overflow) {
      NS_ASSERTION(overflow->OnlyChild(),
                   "must have doc root as canvas frame's only child");
      nsContainerFrame::ReparentFrameViewList(*overflow, prevCanvasFrame, this);
      // Prepend overflow to the our child list. There may already be
      // children placeholders for fixed-pos elements, which don't get
      // reflowed but must not be lost until the canvas frame is destroyed.
      mFrames.InsertFrames(this, nullptr, *overflow);
    }
  }

  // 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 our one and only normal child frame. It's either the root
  // element's frame or a placeholder for that frame, if the root element
  // is abs-pos or fixed-pos. We may have additional children which
  // are placeholders for continuations of fixed-pos content, but those
  // don't need to be reflowed. The normal child is always comes before
  // the fixed-pos placeholders, because we insert it at the start
  // of the child list, above.
  nsHTMLReflowMetrics kidDesiredSize(aReflowState);
  if (mFrames.IsEmpty()) {
    // We have no child frame, so return an empty size
    aDesiredSize.Width() = aDesiredSize.Height() = 0;
  } else {
    nsIFrame* kidFrame = mFrames.FirstChild();
    bool kidDirty = (kidFrame->GetStateBits() & NS_FRAME_IS_DIRTY) != 0;

    nsHTMLReflowState
      kidReflowState(aPresContext, aReflowState, kidFrame,
                     aReflowState.AvailableSize(kidFrame->GetWritingMode()));

    if (aReflowState.IsVResize() &&
        (kidFrame->GetStateBits() & NS_FRAME_CONTAINS_RELATIVE_HEIGHT)) {
      // Tell our kid it's being vertically resized too.  Bit of a
      // hack for framesets.
      kidReflowState.SetVResize(true);
    }

    WritingMode wm = aReflowState.GetWritingMode();
    WritingMode kidWM = kidReflowState.GetWritingMode();
    nscoord containerWidth = aReflowState.ComputedWidth();

    LogicalMargin margin = kidReflowState.ComputedLogicalMargin();
    LogicalPoint kidPt(kidWM, margin.IStart(kidWM), margin.BStart(kidWM));

    kidReflowState.ApplyRelativePositioning(&kidPt, containerWidth);

    // Reflow the frame
    ReflowChild(kidFrame, aPresContext, kidDesiredSize, kidReflowState,
                kidWM, kidPt, containerWidth, 0, aStatus);

    // Complete the reflow and position and size the child frame
    FinishReflowChild(kidFrame, aPresContext, kidDesiredSize, &kidReflowState,
                      kidWM, kidPt, containerWidth, 0);

    if (!NS_FRAME_IS_FULLY_COMPLETE(aStatus)) {
      nsIFrame* nextFrame = kidFrame->GetNextInFlow();
      NS_ASSERTION(nextFrame || aStatus & NS_FRAME_REFLOW_NEXTINFLOW,
        "If it's incomplete and has no nif yet, it must flag a nif reflow.");
      if (!nextFrame) {
        nextFrame = aPresContext->PresShell()->FrameConstructor()->
          CreateContinuingFrame(aPresContext, kidFrame, this);
        SetOverflowFrames(nsFrameList(nextFrame, nextFrame));
        // Root overflow containers will be normal children of
        // the canvas frame, but that's ok because there
        // aren't any other frames we need to isolate them from
        // during reflow.
      }
      if (NS_FRAME_OVERFLOW_IS_INCOMPLETE(aStatus)) {
        nextFrame->AddStateBits(NS_FRAME_IS_OVERFLOW_CONTAINER);
      }
    }

    // If the child frame was just inserted, then we're responsible for making sure
    // it repaints
    if (kidDirty) {
      // But we have a new child, which will affect our background, so
//.........这里部分代码省略.........

void
ViewportFrame::Reflow(nsPresContext*           aPresContext,
                      nsHTMLReflowMetrics&     aDesiredSize,
                      const nsHTMLReflowState& aReflowState,
                      nsReflowStatus&          aStatus)
{
  MarkInReflow();
  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 ComputedBSize() on the child to our
  // ComputedBSize().
  AddStateBits(NS_FRAME_CONTAINS_RELATIVE_BSIZE);

  // 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 kidBSize = 0;
  WritingMode wm = aReflowState.GetWritingMode();

  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.IsVResize() ||
        NS_SUBTREE_DIRTY(mFrames.FirstChild())) {
      // Reflow our one-and-only principal child frame
      nsIFrame*           kidFrame = mFrames.FirstChild();
      nsHTMLReflowMetrics kidDesiredSize(aReflowState);
      WritingMode         wm = kidFrame->GetWritingMode();
      LogicalSize         availableSpace = aReflowState.AvailableSize(wm);
      nsHTMLReflowState   kidReflowState(aPresContext, aReflowState,
                                         kidFrame, availableSpace);

      // Reflow the frame
      kidReflowState.SetComputedBSize(aReflowState.ComputedBSize());
      ReflowChild(kidFrame, aPresContext, kidDesiredSize, kidReflowState,
                  0, 0, 0, aStatus);
      kidBSize = kidDesiredSize.BSize(wm);

      FinishReflowChild(kidFrame, aPresContext, kidDesiredSize, nullptr, 0, 0, 0);
    } else {
      kidBSize = LogicalSize(wm, mFrames.FirstChild()->GetSize()).BSize(wm);
    }
  }

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

  // Return the max size as our desired size
  LogicalSize maxSize(wm, aReflowState.AvailableISize(),
                      // Being flowed initially at an unconstrained block size
                      // means we should return our child's intrinsic size.
                      aReflowState.ComputedBSize() != NS_UNCONSTRAINEDSIZE
                        ? aReflowState.ComputedBSize()
                        : kidBSize);
  aDesiredSize.SetSize(wm, maxSize);
  aDesiredSize.SetOverflowAreasToDesiredBounds();

  if (HasAbsolutelyPositionedChildren()) {
    // 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.AvailableBSize() == 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.AvailableBSize() = maxSize.BSize(wm);
      // Not having border/padding simplifies things
      NS_ASSERTION(reflowState.ComputedPhysicalBorderPadding() == nsMargin(0,0,0,0),
                   "Viewports can't have border/padding");
      reflowState.SetComputedBSize(maxSize.BSize(wm));
    }

    nsRect rect = AdjustReflowStateAsContainingBlock(&reflowState);
    nsOverflowAreas* overflowAreas = &aDesiredSize.mOverflowAreas;
    nsIScrollableFrame* rootScrollFrame =
                    aPresContext->PresShell()->GetRootScrollFrameAsScrollable();
    if (rootScrollFrame && !rootScrollFrame->IsIgnoringViewportClipping()) {
      overflowAreas = nullptr;
    }
    AbsPosReflowFlags flags =
      AbsPosReflowFlags::eCBWidthAndHeightChanged; // XXX could be optimized
    GetAbsoluteContainingBlock()->Reflow(this, aPresContext, reflowState, aStatus,
                                         rect, flags, overflowAreas);
  }

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

//.........这里部分代码省略.........