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218 lines
8.2 KiB
C++
218 lines
8.2 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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* Shyjan Mahamud <mahamud@cs.cmu.edu> (added TeX rendering rules)
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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 "nsMathMLmsubFrame.h"
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//
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// <msub> -- attach a subscript to a base - implementation
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//
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nsIFrame*
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NS_NewMathMLmsubFrame(nsIPresShell* aPresShell, nsStyleContext* aContext)
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{
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return new (aPresShell) nsMathMLmsubFrame(aContext);
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}
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NS_IMPL_FRAMEARENA_HELPERS(nsMathMLmsubFrame)
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nsMathMLmsubFrame::~nsMathMLmsubFrame()
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{
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}
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NS_IMETHODIMP
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nsMathMLmsubFrame::TransmitAutomaticData()
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{
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// if our base is an embellished operator, let its state bubble to us
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mPresentationData.baseFrame = mFrames.FirstChild();
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GetEmbellishDataFrom(mPresentationData.baseFrame, mEmbellishData);
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// 1. The REC says:
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// The <msub> element increments scriptlevel by 1, and sets displaystyle to
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// "false", within subscript, but leaves both attributes unchanged within base.
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// 2. The TeXbook (Ch 17. p.141) says the subscript 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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return NS_OK;
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}
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/* virtual */ nsresult
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nsMathMLmsubFrame::Place (nsIRenderingContext& aRenderingContext,
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PRBool aPlaceOrigin,
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nsHTMLReflowMetrics& aDesiredSize)
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{
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// extra spacing after sup/subscript
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nscoord scriptSpace = nsPresContext::CSSPointsToAppUnits(0.5f); // 0.5pt as in plain TeX
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// check if the subscriptshift attribute is there
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nscoord subScriptShift = 0;
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nsAutoString value;
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GetAttribute(mContent, mPresentationData.mstyle,
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nsGkAtoms::subscriptshift_, value);
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if (!value.IsEmpty()) {
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nsCSSValue cssValue;
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if (ParseNumericValue(value, cssValue) && cssValue.IsLengthUnit()) {
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subScriptShift = CalcLength(PresContext(), mStyleContext, cssValue);
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}
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}
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return nsMathMLmsubFrame::PlaceSubScript(PresContext(),
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aRenderingContext,
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aPlaceOrigin,
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aDesiredSize,
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this,
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subScriptShift,
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scriptSpace);
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}
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// exported routine that both munder and msub share.
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// munder uses this when movablelimits is set.
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nsresult
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nsMathMLmsubFrame::PlaceSubScript (nsPresContext* aPresContext,
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nsIRenderingContext& aRenderingContext,
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PRBool aPlaceOrigin,
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nsHTMLReflowMetrics& aDesiredSize,
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nsMathMLContainerFrame* aFrame,
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nscoord aUserSubScriptShift,
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nscoord aScriptSpace)
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{
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// force the scriptSpace to be atleast 1 pixel
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aScriptSpace = NS_MAX(nsPresContext::CSSPixelsToAppUnits(1), aScriptSpace);
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////////////////////////////////////
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// Get the children's desired sizes
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nsBoundingMetrics bmBase, bmSubScript;
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nsHTMLReflowMetrics baseSize;
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nsHTMLReflowMetrics subScriptSize;
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nsIFrame* baseFrame = aFrame->GetFirstChild(nsnull);
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nsIFrame* subScriptFrame = nsnull;
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if (baseFrame)
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subScriptFrame = baseFrame->GetNextSibling();
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if (!baseFrame || !subScriptFrame || subScriptFrame->GetNextSibling()) {
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// report an error, encourage people to get their markups in order
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return aFrame->ReflowError(aRenderingContext, aDesiredSize);
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}
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GetReflowAndBoundingMetricsFor(baseFrame, baseSize, bmBase);
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GetReflowAndBoundingMetricsFor(subScriptFrame, subScriptSize, bmSubScript);
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// get the subdrop from the subscript font
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nscoord subDrop;
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GetSubDropFromChild(subScriptFrame, subDrop);
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// parameter v, Rule 18a, App. G, TeXbook
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nscoord minSubScriptShift = bmBase.descent + subDrop;
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//////////////////
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// Place Children
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// get min subscript shift limit from x-height
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// = h(x) - 4/5 * sigma_5, Rule 18b, App. G, TeXbook
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nscoord xHeight = 0;
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nsCOMPtr<nsIFontMetrics> fm =
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aPresContext->GetMetricsFor(baseFrame->GetStyleFont()->mFont);
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fm->GetXHeight (xHeight);
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nscoord minShiftFromXHeight = (nscoord)
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(bmSubScript.ascent - (4.0f/5.0f) * xHeight);
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// subScriptShift
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// = minimum amount to shift the subscript down set by user or from the font
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// = sub1 in TeX
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// = subscriptshift attribute * x-height
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nscoord subScriptShift, dummy;
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// get subScriptShift default from font
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GetSubScriptShifts (fm, subScriptShift, dummy);
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subScriptShift =
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NS_MAX(subScriptShift, aUserSubScriptShift);
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// get actual subscriptshift to be used
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// Rule 18b, App. G, TeXbook
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nscoord actualSubScriptShift =
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NS_MAX(minSubScriptShift,NS_MAX(subScriptShift,minShiftFromXHeight));
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// get bounding box for base + subscript
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nsBoundingMetrics boundingMetrics;
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boundingMetrics.ascent =
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NS_MAX(bmBase.ascent, bmSubScript.ascent - actualSubScriptShift);
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boundingMetrics.descent =
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NS_MAX(bmBase.descent, bmSubScript.descent + actualSubScriptShift);
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// add aScriptSpace to the subscript's width
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boundingMetrics.width = bmBase.width + bmSubScript.width + aScriptSpace;
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boundingMetrics.leftBearing = bmBase.leftBearing;
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boundingMetrics.rightBearing = NS_MAX(bmBase.rightBearing, bmBase.width +
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NS_MAX(bmSubScript.width + aScriptSpace, bmSubScript.rightBearing));
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aFrame->SetBoundingMetrics (boundingMetrics);
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// reflow metrics
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aDesiredSize.ascent =
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NS_MAX(baseSize.ascent, subScriptSize.ascent - actualSubScriptShift);
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aDesiredSize.height = aDesiredSize.ascent +
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NS_MAX(baseSize.height - baseSize.ascent,
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subScriptSize.height - subScriptSize.ascent + actualSubScriptShift);
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aDesiredSize.width = boundingMetrics.width;
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aDesiredSize.mBoundingMetrics = boundingMetrics;
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aFrame->SetReference(nsPoint(0, aDesiredSize.ascent));
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if (aPlaceOrigin) {
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nscoord dx, dy;
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// now place the base ...
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dx = 0; dy = aDesiredSize.ascent - baseSize.ascent;
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FinishReflowChild (baseFrame, aPresContext, nsnull, baseSize, dx, dy, 0);
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// ... and subscript
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dx = bmBase.width;
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dy = aDesiredSize.ascent - (subScriptSize.ascent - actualSubScriptShift);
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FinishReflowChild (subScriptFrame, aPresContext, nsnull, subScriptSize, dx, dy, 0);
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}
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return NS_OK;
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}
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