gecko-dev/layout/mathml/nsMathMLmstyleFrame.cpp

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 * Version: MPL 1.1/GPL 2.0/LGPL 2.1
 *
 * The contents of this file are subject to the Mozilla Public License Version
 * 1.1 (the "License"); you may not use this file except in compliance with
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 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
 * for the specific language governing rights and limitations under the
 * License.
 *
 * The Original Code is Mozilla MathML Project.
 *
 * The Initial Developer of the Original Code is
 * The University Of Queensland.
 * Portions created by the Initial Developer are Copyright (C) 1999
 * the Initial Developer. All Rights Reserved.
 *
 * Contributor(s):
 *   Roger B. Sidje <rbs@maths.uq.edu.au>
 *   David J. Fiddes <D.J.Fiddes@hw.ac.uk>
 *
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#include "nsCOMPtr.h"
#include "nsFrame.h"
#include "nsPresContext.h"
#include "nsStyleContext.h"
#include "nsStyleConsts.h"
#include "nsINameSpaceManager.h"
#include "nsIRenderingContext.h"
#include "nsIFontMetrics.h"

#include "nsMathMLmstyleFrame.h"

//
// <mstyle> -- style change
//

nsIFrame*
NS_NewMathMLmstyleFrame(nsIPresShell* aPresShell, nsStyleContext* aContext)
{
  return new (aPresShell) nsMathMLmstyleFrame(aContext);
}

nsMathMLmstyleFrame::~nsMathMLmstyleFrame()
{
}

// mstyle needs special care for its scriptlevel and displaystyle attributes
NS_IMETHODIMP
nsMathMLmstyleFrame::InheritAutomaticData(nsIFrame* aParent) 
{
  // let the base class get the default from our parent
  nsMathMLContainerFrame::InheritAutomaticData(aParent);

  // sync with our current state
  mPresentationData.flags |= NS_MATHML_STRETCH_ALL_CHILDREN_VERTICALLY;
  mPresentationData.mstyle = this;

  // see if the displaystyle attribute is there
  nsMathMLFrame::FindAttrDisplaystyle(mContent, mPresentationData);

  return NS_OK;
}

NS_IMETHODIMP
nsMathMLmstyleFrame::TransmitAutomaticData()
{
  // Nothing particular to do here, the values that we computed in
  // InheritAutomaticData() are the values that we wanted to pass to
  // our children. Our children would have inherited these values in
  // their own InheritAutomaticData() as we descended the frame tree.

  return NS_OK;
}

// displaystyle and scriptlevel are special in <mstyle>...
// Since UpdatePresentation() and UpdatePresentationDataFromChildAt() can be called
// by a parent, ensure that the explicit attributes of <mstyle> take precedence
NS_IMETHODIMP
nsMathMLmstyleFrame::UpdatePresentationData(PRUint32        aFlagsValues,
                                            PRUint32        aWhichFlags)
{
  if (NS_MATHML_HAS_EXPLICIT_DISPLAYSTYLE(mPresentationData.flags)) {
    // our current state takes precedence, disallow updating the displastyle
    aWhichFlags &= ~NS_MATHML_DISPLAYSTYLE;
    aFlagsValues &= ~NS_MATHML_DISPLAYSTYLE;
  }

  return nsMathMLContainerFrame::UpdatePresentationData(aFlagsValues, aWhichFlags);
}

NS_IMETHODIMP
nsMathMLmstyleFrame::UpdatePresentationDataFromChildAt(PRInt32         aFirstIndex,
                                                       PRInt32         aLastIndex,
                                                       PRUint32        aFlagsValues,
                                                       PRUint32        aWhichFlags)
{
  if (NS_MATHML_HAS_EXPLICIT_DISPLAYSTYLE(mPresentationData.flags)) {
    // our current state takes precedence, disallow updating the displastyle
    aWhichFlags &= ~NS_MATHML_DISPLAYSTYLE;
    aFlagsValues &= ~NS_MATHML_DISPLAYSTYLE;
  }

  // let the base class worry about the update
  return
    nsMathMLContainerFrame::UpdatePresentationDataFromChildAt(
      aFirstIndex, aLastIndex, aFlagsValues, aWhichFlags); 
}

NS_IMETHODIMP
nsMathMLmstyleFrame::AttributeChanged(PRInt32         aNameSpaceID,
                                      nsIAtom*        aAttribute,
                                      PRInt32         aModType)
{
  // Other attributes can affect too many things, ask our parent to re-layout
  // its children so that we can pick up changes in our attributes & transmit
  // them in our subtree. However, our siblings will be re-laid too. We used
  // to have a more speedier but more verbose alternative that didn't re-layout
  // our siblings. See bug 114909 - attachment 67668.
  return ReLayoutChildren(mParent);
}