firefox/layout/mathml/nsMathMLmspaceFrame.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 "nsMathMLmspaceFrame.h"

#include "mozilla/dom/MathMLElement.h"
#include "mozilla/PresShell.h"
#include "mozilla/gfx/2D.h"
#include "nsLayoutUtils.h"
#include <algorithm>

using namespace mozilla;

//
// <mspace> -- space - implementation
//

nsIFrame* NS_NewMathMLmspaceFrame(PresShell* aPresShell,
                                  ComputedStyle* aStyle) {
  return new (aPresShell)
      nsMathMLmspaceFrame(aStyle, aPresShell->GetPresContext());
}

NS_IMPL_FRAMEARENA_HELPERS(nsMathMLmspaceFrame)

nsMathMLmspaceFrame::~nsMathMLmspaceFrame() = default;

void nsMathMLmspaceFrame::ProcessAttributes(nsPresContext* aPresContext) {
  nsAutoString value;
  float fontSizeInflation = nsLayoutUtils::FontSizeInflationFor(this);

  // width
  //
  // "Specifies the desired width of the space."
  //
  // values: length
  // default: 0em
  //
  // The default value is "0em", so unitless values can be ignored.
  // <mspace/> is listed among MathML elements allowing negative spacing and
  // the MathML test suite contains "Presentation/TokenElements/mspace/mspace2"
  // as an example. Hence we allow negative values.
  //
  mWidth = 0;
  mContent->AsElement()->GetAttr(nsGkAtoms::width, value);
  if (!value.IsEmpty()) {
    ParseNumericValue(value, &mWidth, dom::MathMLElement::PARSE_ALLOW_NEGATIVE,
                      aPresContext, mComputedStyle, fontSizeInflation);
  }

  // height
  //
  // "Specifies the desired height (above the baseline) of the space."
  //
  // values: length
  // default: 0ex
  //
  // The default value is "0ex", so unitless values can be ignored.
  // We do not allow negative values. See bug 716349.
  //
  mHeight = 0;
  mContent->AsElement()->GetAttr(nsGkAtoms::height, value);
  if (!value.IsEmpty()) {
    ParseNumericValue(value, &mHeight, 0, aPresContext, mComputedStyle,
                      fontSizeInflation);
  }

  // depth
  //
  // "Specifies the desired depth (below the baseline) of the space."
  //
  // values: length
  // default: 0ex
  //
  // The default value is "0ex", so unitless values can be ignored.
  // We do not allow negative values. See bug 716349.
  //
  mDepth = 0;
  mContent->AsElement()->GetAttr(nsGkAtoms::depth_, value);
  if (!value.IsEmpty()) {
    ParseNumericValue(value, &mDepth, 0, aPresContext, mComputedStyle,
                      fontSizeInflation);
  }
}

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

  ProcessAttributes(aPresContext);

  const auto& borderPadding = GetUsedBorderAndPadding();
  mBoundingMetrics = nsBoundingMetrics();
  mBoundingMetrics.width = mWidth + borderPadding.LeftRight();
  mBoundingMetrics.ascent = mHeight + borderPadding.top;
  mBoundingMetrics.descent = mDepth + borderPadding.bottom;
  mBoundingMetrics.leftBearing = 0;
  mBoundingMetrics.rightBearing = mBoundingMetrics.width;

  aDesiredSize.SetBlockStartAscent(mBoundingMetrics.ascent);
  aDesiredSize.Width() = std::max(0, mBoundingMetrics.width);
  aDesiredSize.Height() = mBoundingMetrics.ascent + mBoundingMetrics.descent;
  // Also return our bounding metrics
  aDesiredSize.mBoundingMetrics = mBoundingMetrics;
}

/* virtual */
nsresult nsMathMLmspaceFrame::MeasureForWidth(DrawTarget* aDrawTarget,
                                              ReflowOutput& aDesiredSize) {
  ProcessAttributes(PresContext());
  mBoundingMetrics = nsBoundingMetrics();
  auto offsets = IntrinsicISizeOffsets();
  mBoundingMetrics.width = mWidth + offsets.BorderPadding();
  aDesiredSize.Width() = std::max(0, mBoundingMetrics.width);
  aDesiredSize.mBoundingMetrics = mBoundingMetrics;
  return NS_OK;
}