248 lines
8.0 KiB
C++
248 lines
8.0 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 "nsMathMLmsupFrame.h"
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//
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// <msup> -- attach a superscript to a base - implementation
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//
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nsresult
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NS_NewMathMLmsupFrame(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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nsMathMLmsupFrame* it = new (aPresShell) nsMathMLmsupFrame;
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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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nsMathMLmsupFrame::nsMathMLmsupFrame()
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{
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}
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nsMathMLmsupFrame::~nsMathMLmsupFrame()
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{
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}
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NS_IMETHODIMP
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nsMathMLmsupFrame::Init(nsIPresContext* aPresContext,
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nsIContent* aContent,
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nsIFrame* aParent,
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nsIStyleContext* aContext,
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nsIFrame* aPrevInFlow)
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{
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nsresult rv = nsMathMLContainerFrame::Init
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(aPresContext, aContent, aParent, aContext, aPrevInFlow);
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mSupScriptShift = 0;
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mScriptSpace = NSFloatPointsToTwips(0.5f); // 0.5pt as in plain TeX
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// check if the superscriptshift attribute is there
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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::superscriptshift_, value)) {
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nsCSSValue cssValue;
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if (ParseNumericValue(value, cssValue) && cssValue.IsLengthUnit()) {
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mSupScriptShift = CalcLength(aPresContext, mStyleContext, cssValue);
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}
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}
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#if defined(NS_DEBUG) && defined(SHOW_BOUNDING_BOX)
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// mPresentationData.flags |= NS_MATHML_SHOW_BOUNDING_METRICS;
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#endif
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return rv;
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}
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NS_IMETHODIMP
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nsMathMLmsupFrame::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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nsresult rv = NS_OK;
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////////////////////////////////////
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// Get the children's desired sizes
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PRInt32 count = 0;
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nsRect aRect;
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nsHTMLReflowMetrics baseSize (nsnull);
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nsHTMLReflowMetrics supScriptSize (nsnull);
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nsIFrame* baseFrame = nsnull;
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nsIFrame* supScriptFrame = nsnull;
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// parameter u in Rule 18a, Appendix G of the TeXbook
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nscoord minSupScriptShift = 0;
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nsBoundingMetrics bmBase, bmSupScript;
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nsIFrame* aChildFrame = mFrames.FirstChild();
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while (nsnull != aChildFrame)
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{
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if (!IsOnlyWhitespace(aChildFrame)) {
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if (0 == count) {
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// base
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baseFrame = aChildFrame;
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GetReflowAndBoundingMetricsFor(baseFrame, baseSize, bmBase);
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}
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else if (1 == count) {
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// superscript
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supScriptFrame = aChildFrame;
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GetReflowAndBoundingMetricsFor(supScriptFrame, supScriptSize, bmSupScript);
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// get the supdrop from the supscript font
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nscoord aSupDrop;
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GetSupDropFromChild (aPresContext, supScriptFrame, aSupDrop);
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// parameter u, Rule 18a, App. G, TeXbook
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minSupScriptShift = bmBase.ascent - aSupDrop;
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}
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count++;
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}
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rv = aChildFrame->GetNextSibling(&aChildFrame);
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NS_ASSERTION(NS_SUCCEEDED(rv),"failed to get next child");
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}
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#ifdef NS_DEBUG
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if (2 != count) printf("msup: invalid markup");
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#endif
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if ((2 != count) || !baseFrame || !supScriptFrame) {
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// report an error, encourage people to get their markups in order
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return ReflowError(aPresContext, aRenderingContext, aDesiredSize);
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}
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//////////////////
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// Place Children
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// get min supscript shift limit from x-height
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// = d(x) + 1/4 * sigma_5, Rule 18c, App. G, TeXbook
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nscoord xHeight = 0;
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nsCOMPtr<nsIFontMetrics> fm;
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// const nsStyleFont* aFont =
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// (const nsStyleFont*) mStyleContext->GetStyleData (eStyleStruct_Font);
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const nsStyleFont *aFont;
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baseFrame->GetStyleData(eStyleStruct_Font, (const nsStyleStruct *&)aFont);
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aPresContext->GetMetricsFor (aFont->mFont, getter_AddRefs(fm));
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fm->GetXHeight (xHeight);
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nscoord minShiftFromXHeight = (nscoord)
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(bmSupScript.descent + (1.0f/4.0f) * xHeight);
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// aSupScriptShift{1,2,3}
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// = minimum amount to shift the supscript up
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// = sup{1,2,3} in TeX
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// aSupScriptShift1 = superscriptshift attribute * x-height
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// Note that there are THREE values for supscript shifts depending
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// on the current style
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nscoord aSupScriptShift1, aSupScriptShift2, aSupScriptShift3;
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// Set aSupScriptShift{1,2,3} default from font
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GetSupScriptShifts (fm, aSupScriptShift1, aSupScriptShift2, aSupScriptShift3);
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if (0 < mSupScriptShift) {
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// the user has set the superscriptshift attribute
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float aFactor2 = ((float) aSupScriptShift2) / aSupScriptShift1;
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float aFactor3 = ((float) aSupScriptShift3) / aSupScriptShift1;
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aSupScriptShift1 =
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PR_MAX(aSupScriptShift1, mSupScriptShift);
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aSupScriptShift2 = NSToCoordRound(aFactor2 * aSupScriptShift1);
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aSupScriptShift3 = NSToCoordRound(aFactor3 * aSupScriptShift1);
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}
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// get sup script shift depending on current script level and display style
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// Rule 18c, App. G, TeXbook
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nscoord aSupScriptShift;
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if ( mPresentationData.scriptLevel == 0 &&
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NS_MATHML_IS_DISPLAYSTYLE(mPresentationData.flags) &&
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!NS_MATHML_IS_COMPRESSED(mPresentationData.flags)) {
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// Style D in TeXbook
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aSupScriptShift = aSupScriptShift1;
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}
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else if (NS_MATHML_IS_COMPRESSED(mPresentationData.flags)) {
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// Style C' in TeXbook = D',T',S',SS'
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aSupScriptShift = aSupScriptShift3;
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}
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else {
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// everything else = T,S,SS
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aSupScriptShift = aSupScriptShift2;
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}
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// get actual supscriptshift to be used
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// Rule 18c, App. G, TeXbook
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nscoord actualSupScriptShift =
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PR_MAX(minSupScriptShift,PR_MAX(aSupScriptShift,minShiftFromXHeight));
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// bounding box
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mBoundingMetrics.ascent =
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PR_MAX(bmBase.ascent, (bmSupScript.ascent + actualSupScriptShift));
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mBoundingMetrics.descent =
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PR_MAX(bmBase.descent, (bmSupScript.descent - actualSupScriptShift));
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// add mScriptSpace between base and supscript
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mBoundingMetrics.width = bmBase.width + mScriptSpace + bmSupScript.width;
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mBoundingMetrics.leftBearing = bmBase.leftBearing;
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mBoundingMetrics.rightBearing = bmBase.width + mScriptSpace + bmSupScript.rightBearing;
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// reflow metrics
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aDesiredSize.ascent =
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PR_MAX(baseSize.ascent, (supScriptSize.ascent + actualSupScriptShift));
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aDesiredSize.descent =
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PR_MAX(baseSize.descent, (supScriptSize.descent - actualSupScriptShift));
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aDesiredSize.height = aDesiredSize.ascent + aDesiredSize.descent;
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aDesiredSize.width = baseSize.width + mScriptSpace + supScriptSize.width;
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mReference.x = 0;
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mReference.y = 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, baseSize, dx, dy, 0);
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// ... and supscript
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dx = baseSize.width + mScriptSpace;
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dy = aDesiredSize.ascent - (supScriptSize.ascent + actualSupScriptShift);
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FinishReflowChild (supScriptFrame, aPresContext, supScriptSize, dx, dy, 0);
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}
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return NS_OK;
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}
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