fune/layout/mathml/nsMathMLSelectedFrame.cpp

/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#include "nsMathMLSelectedFrame.h"
#include "nsDisplayList.h"

using namespace mozilla;

nsMathMLSelectedFrame::~nsMathMLSelectedFrame() = default;

NS_IMETHODIMP
nsMathMLSelectedFrame::TransmitAutomaticData() {
  // Note that to determine space-like and embellished op properties:
  //   - <semantics> behaves the same as <maction>
  //   - <annotation-xml> behaves the same as <mrow>

  // The REC defines the following element to be space-like:
  // * an maction element whose selected sub-expression exists and is
  //   space-like;
  nsIMathMLFrame* mathMLFrame = do_QueryFrame(mSelectedFrame);
  if (mathMLFrame && mathMLFrame->IsSpaceLike()) {
    mPresentationData.flags |= NS_MATHML_SPACE_LIKE;
  } else {
    mPresentationData.flags &= ~NS_MATHML_SPACE_LIKE;
  }

  // The REC defines the following element to be an embellished operator:
  // * an maction element whose selected sub-expression exists and is an
  //   embellished operator;
  mPresentationData.baseFrame = mSelectedFrame;
  GetEmbellishDataFrom(mSelectedFrame, mEmbellishData);

  return NS_OK;
}

nsresult nsMathMLSelectedFrame::ChildListChanged(int32_t aModType) {
  GetSelectedFrame();
  return nsMathMLContainerFrame::ChildListChanged(aModType);
}

void nsMathMLSelectedFrame::SetInitialChildList(ChildListID aListID,
                                                nsFrameList&& aChildList) {
  nsMathMLContainerFrame::SetInitialChildList(aListID, std::move(aChildList));
  // This very first call to GetSelectedFrame() will cause us to be marked as an
  // embellished operator if the selected child is an embellished operator
  GetSelectedFrame();
}

//  Only paint the selected child...
void nsMathMLSelectedFrame::BuildDisplayList(nsDisplayListBuilder* aBuilder,
                                             const nsDisplayListSet& aLists) {
  // Report an error if something wrong was found in this frame.
  // We can't call nsDisplayMathMLError from here,
  // so ask nsMathMLContainerFrame to do the work for us.
  if (NS_MATHML_HAS_ERROR(mPresentationData.flags)) {
    nsMathMLContainerFrame::BuildDisplayList(aBuilder, aLists);
    return;
  }

  DisplayBorderBackgroundOutline(aBuilder, aLists);

  nsIFrame* childFrame = GetSelectedFrame();
  if (childFrame) {
    // Put the child's background directly onto the content list
    nsDisplayListSet set(aLists, aLists.Content());
    // The children should be in content order
    BuildDisplayListForChild(aBuilder, childFrame, set);
  }

#if defined(DEBUG) && defined(SHOW_BOUNDING_BOX)
  // visual debug
  DisplayBoundingMetrics(aBuilder, this, mReference, mBoundingMetrics, aLists);
#endif
}

/* virtual */
nsIFrame::SizeComputationResult nsMathMLSelectedFrame::ComputeSize(
    gfxContext* aRenderingContext, WritingMode aWM, const LogicalSize& aCBSize,
    nscoord aAvailableISize, const LogicalSize& aMargin,
    const LogicalSize& aBorderPadding, const StyleSizeOverrides& aSizeOverrides,
    ComputeSizeFlags aFlags) {
  nsIFrame* childFrame = GetSelectedFrame();
  if (childFrame) {
    // Delegate size computation to the child frame.
    // Try to account for border/padding/margin on this frame and the child,
    // though we don't really support them during reflow anyway...
    const nscoord availableISize =
        aAvailableISize - aBorderPadding.ISize(aWM) - aMargin.ISize(aWM);
    const LogicalSize cbSize = aCBSize - aBorderPadding - aMargin;
    SizeComputationInput offsetState(childFrame, aRenderingContext, aWM,
                                     availableISize);
    const auto bpSize = offsetState.ComputedLogicalBorderPadding(aWM).Size(aWM);
    auto size = childFrame->ComputeSize(
        aRenderingContext, aWM, cbSize, availableISize,
        offsetState.ComputedLogicalMargin(aWM).Size(aWM), bpSize,
        aSizeOverrides, aFlags);
    return {size.mLogicalSize + bpSize, size.mAspectRatioUsage};
  }
  return {LogicalSize(aWM), AspectRatioUsage::None};
}

// Only reflow the selected child ...
void nsMathMLSelectedFrame::Reflow(nsPresContext* aPresContext,
                                   ReflowOutput& aDesiredSize,
                                   const ReflowInput& aReflowInput,
                                   nsReflowStatus& aStatus) {
  MarkInReflow();
  MOZ_ASSERT(aStatus.IsEmpty(), "Caller should pass a fresh reflow status!");

  mPresentationData.flags &= ~NS_MATHML_ERROR;
  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);
}

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

  if (mInvalidMarkup) {
    // Calling PlaceForError when mathml.error_message_layout_for_invalid_markup
    // is disabled causes assertion failures because nsMathMLSelectedFrame only
    // performs layout of the selected child. However, this code is only reached
    // when mathml.legacy_maction_and_semantics_implementations is enabled, so
    // it is out the scope of the mrow fallback described in MathML Core and
    // nsMathMLSelectedFrame will go away in the future. So for now let's
    // continue to always layout this case as an 'invalid-markup' message.
    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,
                        ReflowChildFlags::Default);
    }
    mReference.x = 0;
    mReference.y = aDesiredSize.BlockStartAscent();
  }
  aDesiredSize.mBoundingMetrics = mBoundingMetrics;
  return NS_OK;
}