243 lines
8.6 KiB
C++
243 lines
8.6 KiB
C++
/*
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* The contents of this file are subject to the Mozilla Public
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* License Version 1.1 (the "License"); you may not use this file
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* except in compliance with the License. You may obtain a copy of
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* the License at http://www.mozilla.org/MPL/
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*
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* Software distributed under the License is distributed on an "AS
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* IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or
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* implied. See the License for the specific language governing
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* rights and limitations under the 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 The University Of
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* Queensland. Portions created by The University Of Queensland are
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* Copyright (C) 1999 The University Of Queensland. 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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#include "nsCOMPtr.h"
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#include "nsHTMLParts.h"
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#include "nsIHTMLContent.h"
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#include "nsFrame.h"
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#include "nsLineLayout.h"
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#include "nsHTMLIIDs.h"
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#include "nsIPresContext.h"
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#include "nsHTMLAtoms.h"
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#include "nsUnitConversion.h"
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#include "nsIStyleContext.h"
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#include "nsStyleConsts.h"
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#include "nsINameSpaceManager.h"
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#include "nsIRenderingContext.h"
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#include "nsIFontMetrics.h"
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#include "nsStyleUtil.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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nsresult
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NS_NewMathMLmsubFrame(nsIPresShell* aPresShell, nsIFrame** aNewFrame)
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{
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NS_PRECONDITION(aNewFrame, "null OUT ptr");
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if (nsnull == aNewFrame) {
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return NS_ERROR_NULL_POINTER;
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}
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nsMathMLmsubFrame* it = new (aPresShell) nsMathMLmsubFrame;
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if (nsnull == it) {
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return NS_ERROR_OUT_OF_MEMORY;
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}
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*aNewFrame = it;
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return NS_OK;
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}
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nsMathMLmsubFrame::nsMathMLmsubFrame()
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{
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}
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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(nsIPresContext* aPresContext)
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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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nsIFrame* baseFrame = mFrames.FirstChild();
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GetEmbellishDataFrom(baseFrame, mEmbellishData);
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if (NS_MATHML_IS_EMBELLISH_OPERATOR(mEmbellishData.flags))
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mEmbellishData.nextFrame = baseFrame;
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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(aPresContext, 1, -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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NS_IMETHODIMP
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nsMathMLmsubFrame::Place (nsIPresContext* aPresContext,
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nsIRenderingContext& aRenderingContext,
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PRBool aPlaceOrigin,
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nsHTMLReflowMetrics& aDesiredSize)
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{
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// extra spacing between base and sup/subscript
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nscoord scriptSpace = NSFloatPointsToTwips(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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if (NS_CONTENT_ATTR_HAS_VALUE == GetAttribute(mContent, mPresentationData.mstyle,
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nsMathMLAtoms::subscriptshift_, value)) {
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nsCSSValue cssValue;
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if (ParseNumericValue(value, cssValue) && cssValue.IsLengthUnit()) {
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subScriptShift = CalcLength(aPresContext, mStyleContext, cssValue);
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}
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}
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return nsMathMLmsubFrame::PlaceSubScript(aPresContext,
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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 (nsIPresContext* aPresContext,
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nsIRenderingContext& aRenderingContext,
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PRBool aPlaceOrigin,
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nsHTMLReflowMetrics& aDesiredSize,
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nsIFrame* aFrame,
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nscoord aUserSubScriptShift,
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nscoord aScriptSpace)
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{
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// the caller better be a mathml frame
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nsIMathMLFrame* mathMLFrame;
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aFrame->QueryInterface(NS_GET_IID(nsIMathMLFrame), (void**)&mathMLFrame);
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if (!mathMLFrame) return NS_ERROR_INVALID_ARG;
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// force the scriptSpace to be atleast 1 pixel
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float p2t;
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aPresContext->GetScaledPixelsToTwips(&p2t);
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aScriptSpace = PR_MAX(NSIntPixelsToTwips(1, p2t), 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(nsnull);
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nsHTMLReflowMetrics subScriptSize(nsnull);
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nsIFrame* baseFrame;
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aFrame->FirstChild(aPresContext, nsnull, &baseFrame);
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nsIFrame* subScriptFrame = nsnull;
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if (baseFrame)
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baseFrame->GetNextSibling(&subScriptFrame);
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if (!baseFrame || !subScriptFrame || HasNextSibling(subScriptFrame)) {
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// report an error, encourage people to get their markups in order
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NS_WARNING("invalid markup");
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return NS_STATIC_CAST(nsMathMLContainerFrame*,
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aFrame)->ReflowError(aPresContext,
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aRenderingContext,
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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(aPresContext, 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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const nsStyleFont* font;
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baseFrame->GetStyleData(eStyleStruct_Font, (const nsStyleStruct *&)font);
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aPresContext->GetMetricsFor (font->mFont, getter_AddRefs(fm));
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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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PR_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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PR_MAX(minSubScriptShift,PR_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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PR_MAX(bmBase.ascent, bmSubScript.ascent - actualSubScriptShift);
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boundingMetrics.descent =
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PR_MAX(bmBase.descent, bmSubScript.descent + actualSubScriptShift);
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// add aScriptSpace between base and supscript
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boundingMetrics.width =
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bmBase.width
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+ aScriptSpace
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+ bmSubScript.width;
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boundingMetrics.leftBearing = bmBase.leftBearing;
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boundingMetrics.rightBearing =
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bmBase.width
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+ aScriptSpace
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+ bmSubScript.rightBearing;
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mathMLFrame->SetBoundingMetrics (boundingMetrics);
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// reflow metrics
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aDesiredSize.ascent =
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PR_MAX(baseSize.ascent, subScriptSize.ascent - actualSubScriptShift);
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aDesiredSize.descent =
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PR_MAX(baseSize.descent, subScriptSize.descent + actualSubScriptShift);
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aDesiredSize.height = aDesiredSize.ascent + aDesiredSize.descent;
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aDesiredSize.width = bmBase.width + aScriptSpace + subScriptSize.width;
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aDesiredSize.mBoundingMetrics = boundingMetrics;
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mathMLFrame->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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// XXX adding mScriptSpace seems to add more space than i like
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// may want to remove later.
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dx = bmBase.width + aScriptSpace;
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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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