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449 lines
16 KiB
C++
449 lines
16 KiB
C++
/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
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/* ***** BEGIN LICENSE BLOCK *****
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* Version: MPL 1.1/GPL 2.0/LGPL 2.1
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*
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* The contents of this file are subject to the Mozilla Public License Version
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* 1.1 (the "License"); you may not use this file except in compliance with
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* the License. You may obtain a copy of the License at
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* http://www.mozilla.org/MPL/
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*
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* Software distributed under the License is distributed on an "AS IS" basis,
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* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
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* for the specific language governing rights and limitations under the
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* License.
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*
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* The Original Code is Mozilla MathML Project.
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*
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* The Initial Developer of the Original Code is
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* The University Of Queensland.
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* Portions created by the Initial Developer are Copyright (C) 1999
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* the Initial Developer. All Rights Reserved.
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*
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* Contributor(s):
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* Roger B. Sidje <rbs@maths.uq.edu.au>
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* David J. Fiddes <D.J.Fiddes@hw.ac.uk>
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* Vilya Harvey <vilya@nag.co.uk>
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* Shyjan Mahamud <mahamud@cs.cmu.edu>
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*
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* Alternatively, the contents of this file may be used under the terms of
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* either of the GNU General Public License Version 2 or later (the "GPL"),
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* or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
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* in which case the provisions of the GPL or the LGPL are applicable instead
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* of those above. If you wish to allow use of your version of this file only
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* under the terms of either the GPL or the LGPL, and not to allow others to
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* use your version of this file under the terms of the MPL, indicate your
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* decision by deleting the provisions above and replace them with the notice
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* and other provisions required by the GPL or the LGPL. If you do not delete
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* the provisions above, a recipient may use your version of this file under
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* the terms of any one of the MPL, the GPL or the LGPL.
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*
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* ***** END LICENSE BLOCK ***** */
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#include "nsCOMPtr.h"
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#include "nsFrame.h"
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#include "nsPresContext.h"
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#include "nsStyleContext.h"
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#include "nsStyleConsts.h"
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#include "nsIRenderingContext.h"
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#include "nsIFontMetrics.h"
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#include "nsMathMLmrootFrame.h"
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//
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// <msqrt> and <mroot> -- form a radical - implementation
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//
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//NOTE:
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// The code assumes that TeX fonts are picked.
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// There is no fall-back to draw the branches of the sqrt explicitly
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// in the case where TeX fonts are not there. In general, there are no
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// fall-back(s) in MathML when some (freely-downloadable) fonts are missing.
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// Otherwise, this will add much work and unnecessary complexity to the core
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// MathML engine. Assuming that authors have the free fonts is part of the
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// deal. We are not responsible for cases of misconfigurations out there.
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// additional style context to be used by our MathMLChar.
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#define NS_SQR_CHAR_STYLE_CONTEXT_INDEX 0
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static const PRUnichar kSqrChar = PRUnichar(0x221A);
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nsIFrame*
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NS_NewMathMLmrootFrame(nsIPresShell* aPresShell, nsStyleContext* aContext)
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{
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return new (aPresShell) nsMathMLmrootFrame(aContext);
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}
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NS_IMPL_FRAMEARENA_HELPERS(nsMathMLmrootFrame)
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nsMathMLmrootFrame::nsMathMLmrootFrame(nsStyleContext* aContext) :
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nsMathMLContainerFrame(aContext),
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mSqrChar(),
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mBarRect()
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{
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}
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nsMathMLmrootFrame::~nsMathMLmrootFrame()
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{
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}
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NS_IMETHODIMP
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nsMathMLmrootFrame::Init(nsIContent* aContent,
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nsIFrame* aParent,
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nsIFrame* aPrevInFlow)
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{
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nsresult rv = nsMathMLContainerFrame::Init(aContent, aParent, aPrevInFlow);
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nsPresContext *presContext = PresContext();
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// No need to track the style context given to our MathML char.
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// The Style System will use Get/SetAdditionalStyleContext() to keep it
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// up-to-date if dynamic changes arise.
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nsAutoString sqrChar; sqrChar.Assign(kSqrChar);
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mSqrChar.SetData(presContext, sqrChar);
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ResolveMathMLCharStyle(presContext, mContent, mStyleContext, &mSqrChar, PR_TRUE);
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return rv;
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}
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NS_IMETHODIMP
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nsMathMLmrootFrame::TransmitAutomaticData()
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{
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// 1. The REC says:
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// The <mroot> element increments scriptlevel by 2, and sets displaystyle to
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// "false", within index, but leaves both attributes unchanged within base.
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// 2. The TeXbook (Ch 17. p.141) says \sqrt is compressed
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UpdatePresentationDataFromChildAt(1, 1,
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~NS_MATHML_DISPLAYSTYLE | NS_MATHML_COMPRESSED,
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NS_MATHML_DISPLAYSTYLE | NS_MATHML_COMPRESSED);
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UpdatePresentationDataFromChildAt(0, 0,
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NS_MATHML_COMPRESSED, NS_MATHML_COMPRESSED);
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return NS_OK;
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}
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NS_IMETHODIMP
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nsMathMLmrootFrame::BuildDisplayList(nsDisplayListBuilder* aBuilder,
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const nsRect& aDirtyRect,
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const nsDisplayListSet& aLists)
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{
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/////////////
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// paint the content we are square-rooting
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nsresult rv = nsMathMLContainerFrame::BuildDisplayList(aBuilder, aDirtyRect, aLists);
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NS_ENSURE_SUCCESS(rv, rv);
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/////////////
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// paint the sqrt symbol
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if (!NS_MATHML_HAS_ERROR(mPresentationData.flags)) {
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rv = mSqrChar.Display(aBuilder, this, aLists);
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NS_ENSURE_SUCCESS(rv, rv);
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rv = DisplayBar(aBuilder, this, mBarRect, aLists);
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NS_ENSURE_SUCCESS(rv, rv);
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#if defined(NS_DEBUG) && defined(SHOW_BOUNDING_BOX)
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// for visual debug
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nsRect rect;
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mSqrChar.GetRect(rect);
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nsBoundingMetrics bm;
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mSqrChar.GetBoundingMetrics(bm);
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rv = DisplayBoundingMetrics(aBuilder, this, rect.TopLeft(), bm, aLists);
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#endif
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}
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return rv;
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}
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static void
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GetRadicalXOffsets(nscoord aIndexWidth, nscoord aSqrWidth,
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nsIFontMetrics* aFontMetrics,
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nscoord* aIndexOffset, nscoord* aSqrOffset)
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{
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// The index is tucked in closer to the radical while making sure
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// that the kern does not make the index and radical collide
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nscoord dxIndex, dxSqr;
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nscoord xHeight = 0;
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aFontMetrics->GetXHeight(xHeight);
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nscoord indexRadicalKern = NSToCoordRound(1.35f * xHeight);
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if (indexRadicalKern > aIndexWidth) {
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dxIndex = indexRadicalKern - aIndexWidth;
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dxSqr = 0;
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}
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else {
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dxIndex = 0;
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dxSqr = aIndexWidth - indexRadicalKern;
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}
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// avoid collision by leaving a minimum space between index and radical
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nscoord minimumClearance = aSqrWidth/2;
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if (dxIndex + aIndexWidth + minimumClearance > dxSqr + aSqrWidth) {
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if (aIndexWidth + minimumClearance < aSqrWidth) {
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dxIndex = aSqrWidth - (aIndexWidth + minimumClearance);
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dxSqr = 0;
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}
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else {
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dxIndex = 0;
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dxSqr = (aIndexWidth + minimumClearance) - aSqrWidth;
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}
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}
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if (aIndexOffset)
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*aIndexOffset = dxIndex;
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if (aSqrOffset)
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*aSqrOffset = dxSqr;
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}
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NS_IMETHODIMP
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nsMathMLmrootFrame::Reflow(nsPresContext* aPresContext,
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nsHTMLReflowMetrics& aDesiredSize,
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const nsHTMLReflowState& aReflowState,
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nsReflowStatus& aStatus)
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{
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nsresult rv = NS_OK;
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nsSize availSize(aReflowState.ComputedWidth(), NS_UNCONSTRAINEDSIZE);
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nsReflowStatus childStatus;
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aDesiredSize.width = aDesiredSize.height = 0;
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aDesiredSize.ascent = 0;
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nsBoundingMetrics bmSqr, bmBase, bmIndex;
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nsIRenderingContext& renderingContext = *aReflowState.rendContext;
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//////////////////
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// Reflow Children
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PRInt32 count = 0;
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nsIFrame* baseFrame = nsnull;
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nsIFrame* indexFrame = nsnull;
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nsHTMLReflowMetrics baseSize;
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nsHTMLReflowMetrics indexSize;
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nsIFrame* childFrame = mFrames.FirstChild();
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while (childFrame) {
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// ask our children to compute their bounding metrics
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nsHTMLReflowMetrics childDesiredSize(aDesiredSize.mFlags
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| NS_REFLOW_CALC_BOUNDING_METRICS);
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nsHTMLReflowState childReflowState(aPresContext, aReflowState,
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childFrame, availSize);
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rv = ReflowChild(childFrame, aPresContext,
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childDesiredSize, childReflowState, childStatus);
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//NS_ASSERTION(NS_FRAME_IS_COMPLETE(childStatus), "bad status");
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if (NS_FAILED(rv)) {
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// Call DidReflow() for the child frames we successfully did reflow.
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DidReflowChildren(mFrames.FirstChild(), childFrame);
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return rv;
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}
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if (0 == count) {
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// base
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baseFrame = childFrame;
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baseSize = childDesiredSize;
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bmBase = childDesiredSize.mBoundingMetrics;
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}
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else if (1 == count) {
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// index
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indexFrame = childFrame;
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indexSize = childDesiredSize;
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bmIndex = childDesiredSize.mBoundingMetrics;
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}
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count++;
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childFrame = childFrame->GetNextSibling();
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}
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if (2 != count) {
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// report an error, encourage people to get their markups in order
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rv = ReflowError(renderingContext, aDesiredSize);
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aStatus = NS_FRAME_COMPLETE;
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NS_FRAME_SET_TRUNCATION(aStatus, aReflowState, aDesiredSize);
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// Call DidReflow() for the child frames we successfully did reflow.
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DidReflowChildren(mFrames.FirstChild(), childFrame);
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return rv;
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}
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////////////
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// Prepare the radical symbol and the overline bar
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renderingContext.SetFont(GetStyleFont()->mFont,
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aPresContext->GetUserFontSet());
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nsCOMPtr<nsIFontMetrics> fm;
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renderingContext.GetFontMetrics(*getter_AddRefs(fm));
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// For radical glyphs from TeX fonts and some of the radical glyphs from
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// Mathematica fonts, the thickness of the overline can be obtained from the
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// ascent of the glyph. Most fonts however have radical glyphs above the
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// baseline so no assumption can be made about the meaning of the ascent.
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nscoord ruleThickness, leading, em;
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GetRuleThickness(renderingContext, fm, ruleThickness);
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nsBoundingMetrics bmOne;
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renderingContext.GetBoundingMetrics(NS_LITERAL_STRING("1").get(), 1, bmOne);
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// get the leading to be left at the top of the resulting frame
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// this seems more reliable than using fm->GetLeading() on suspicious fonts
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GetEmHeight(fm, em);
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leading = nscoord(0.2f * em);
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// Rule 11, App. G, TeXbook
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// psi = clearance between rule and content
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nscoord phi = 0, psi = 0;
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if (NS_MATHML_IS_DISPLAYSTYLE(mPresentationData.flags))
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fm->GetXHeight(phi);
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else
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phi = ruleThickness;
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psi = ruleThickness + phi/4;
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// built-in: adjust clearance psi to emulate \mathstrut using '1' (TexBook, p.131)
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if (bmOne.ascent > bmBase.ascent)
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psi += bmOne.ascent - bmBase.ascent;
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// make sure that the rule appears on on screen
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nscoord onePixel = nsPresContext::CSSPixelsToAppUnits(1);
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if (ruleThickness < onePixel) {
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ruleThickness = onePixel;
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}
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// adjust clearance psi to get an exact number of pixels -- this
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// gives a nicer & uniform look on stacked radicals (bug 130282)
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nscoord delta = psi % onePixel;
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if (delta)
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psi += onePixel - delta; // round up
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// Stretch the radical symbol to the appropriate height if it is not big enough.
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nsBoundingMetrics contSize = bmBase;
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contSize.descent = bmBase.ascent + bmBase.descent + psi;
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contSize.ascent = ruleThickness;
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// height(radical) should be >= height(base) + psi + ruleThickness
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nsBoundingMetrics radicalSize;
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mSqrChar.Stretch(aPresContext, renderingContext,
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NS_STRETCH_DIRECTION_VERTICAL,
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contSize, radicalSize,
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NS_STRETCH_LARGER);
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// radicalSize have changed at this point, and should match with
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// the bounding metrics of the char
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mSqrChar.GetBoundingMetrics(bmSqr);
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// Update the desired size for the container (like msqrt, index is not yet included)
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// the baseline will be that of the base.
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mBoundingMetrics.ascent = bmBase.ascent + psi + ruleThickness;
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mBoundingMetrics.descent =
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NS_MAX(bmBase.descent,
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(bmSqr.ascent + bmSqr.descent - mBoundingMetrics.ascent));
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mBoundingMetrics.width = bmSqr.width + bmBase.width;
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mBoundingMetrics.leftBearing = bmSqr.leftBearing;
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mBoundingMetrics.rightBearing = bmSqr.width +
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NS_MAX(bmBase.width, bmBase.rightBearing); // take also care of the rule
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aDesiredSize.ascent = mBoundingMetrics.ascent + leading;
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aDesiredSize.height = aDesiredSize.ascent +
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NS_MAX(baseSize.height - baseSize.ascent,
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mBoundingMetrics.descent + ruleThickness);
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aDesiredSize.width = mBoundingMetrics.width;
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/////////////
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// Re-adjust the desired size to include the index.
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// the index is raised by some fraction of the height
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// of the radical, see \mroot macro in App. B, TexBook
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nscoord raiseIndexDelta = NSToCoordRound(0.6f * (bmSqr.ascent + bmSqr.descent));
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nscoord indexRaisedAscent = mBoundingMetrics.ascent // top of radical
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- (bmSqr.ascent + bmSqr.descent) // to bottom of radical
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+ raiseIndexDelta + bmIndex.ascent + bmIndex.descent; // to top of raised index
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nscoord indexClearance = 0;
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if (mBoundingMetrics.ascent < indexRaisedAscent) {
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indexClearance =
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indexRaisedAscent - mBoundingMetrics.ascent; // excess gap introduced by a tall index
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mBoundingMetrics.ascent = indexRaisedAscent;
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nscoord descent = aDesiredSize.height - aDesiredSize.ascent;
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aDesiredSize.ascent = mBoundingMetrics.ascent + leading;
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aDesiredSize.height = aDesiredSize.ascent + descent;
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}
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nscoord dxIndex, dxSqr;
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GetRadicalXOffsets(bmIndex.width, bmSqr.width, fm, &dxIndex, &dxSqr);
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// place the index
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nscoord dx = dxIndex;
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nscoord dy = aDesiredSize.ascent - (indexRaisedAscent + indexSize.ascent - bmIndex.ascent);
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FinishReflowChild(indexFrame, aPresContext, nsnull, indexSize, dx, dy, 0);
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// place the radical symbol and the radical bar
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dx = dxSqr;
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dy = indexClearance + leading; // leave a leading at the top
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mSqrChar.SetRect(nsRect(dx, dy, bmSqr.width, bmSqr.ascent + bmSqr.descent));
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dx += bmSqr.width;
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mBarRect.SetRect(dx, dy, bmBase.width, ruleThickness);
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// place the base
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dy = aDesiredSize.ascent - baseSize.ascent;
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FinishReflowChild(baseFrame, aPresContext, nsnull, baseSize, dx, dy, 0);
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mReference.x = 0;
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mReference.y = aDesiredSize.ascent;
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mBoundingMetrics.width = dx + bmBase.width;
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mBoundingMetrics.leftBearing =
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NS_MIN(dxIndex + bmIndex.leftBearing, dxSqr + bmSqr.leftBearing);
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mBoundingMetrics.rightBearing = dx +
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NS_MAX(bmBase.width, bmBase.rightBearing);
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aDesiredSize.width = mBoundingMetrics.width;
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aDesiredSize.mBoundingMetrics = mBoundingMetrics;
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GatherAndStoreOverflow(&aDesiredSize);
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aStatus = NS_FRAME_COMPLETE;
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NS_FRAME_SET_TRUNCATION(aStatus, aReflowState, aDesiredSize);
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return NS_OK;
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}
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/* virtual */ nscoord
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nsMathMLmrootFrame::GetIntrinsicWidth(nsIRenderingContext* aRenderingContext)
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{
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nsIFrame* baseFrame = mFrames.FirstChild();
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nsIFrame* indexFrame = nsnull;
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if (baseFrame)
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indexFrame = baseFrame->GetNextSibling();
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if (!indexFrame || indexFrame->GetNextSibling()) {
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nsHTMLReflowMetrics desiredSize;
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ReflowError(*aRenderingContext, desiredSize);
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return desiredSize.width;
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}
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nscoord baseWidth =
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nsLayoutUtils::IntrinsicForContainer(aRenderingContext, baseFrame,
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nsLayoutUtils::PREF_WIDTH);
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nscoord indexWidth =
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nsLayoutUtils::IntrinsicForContainer(aRenderingContext, indexFrame,
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nsLayoutUtils::PREF_WIDTH);
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nscoord sqrWidth = mSqrChar.GetMaxWidth(PresContext(), *aRenderingContext);
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nsCOMPtr<nsIFontMetrics> fm;
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aRenderingContext->GetFontMetrics(*getter_AddRefs(fm));
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nscoord dxSqr;
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GetRadicalXOffsets(indexWidth, sqrWidth, fm, nsnull, &dxSqr);
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return dxSqr + sqrWidth + baseWidth;
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}
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// ----------------------
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// the Style System will use these to pass the proper style context to our MathMLChar
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nsStyleContext*
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nsMathMLmrootFrame::GetAdditionalStyleContext(PRInt32 aIndex) const
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{
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switch (aIndex) {
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case NS_SQR_CHAR_STYLE_CONTEXT_INDEX:
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return mSqrChar.GetStyleContext();
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break;
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default:
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return nsnull;
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}
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}
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void
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nsMathMLmrootFrame::SetAdditionalStyleContext(PRInt32 aIndex,
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nsStyleContext* aStyleContext)
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{
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switch (aIndex) {
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case NS_SQR_CHAR_STYLE_CONTEXT_INDEX:
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mSqrChar.SetStyleContext(aStyleContext);
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break;
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}
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}
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