mirror of
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254 lines
9.8 KiB
C++
254 lines
9.8 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 "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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nsIFrame*
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NS_NewMathMLmsupFrame(nsIPresShell* aPresShell, nsStyleContext* aContext)
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{
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return new (aPresShell) nsMathMLmsupFrame(aContext);
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}
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NS_IMPL_FRAMEARENA_HELPERS(nsMathMLmsupFrame)
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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::TransmitAutomaticData()
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{
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// if our base is an embellished operator, its flags 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 <msup> element increments scriptlevel by 1, and sets displaystyle to
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// "false", within superscript, but leaves both attributes unchanged within base.
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// 2. The TeXbook (Ch 17. p.141) says the superscript *inherits* the compression,
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// so we don't set the compression flag. Our parent will propagate its own.
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UpdatePresentationDataFromChildAt(1, -1,
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~NS_MATHML_DISPLAYSTYLE,
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NS_MATHML_DISPLAYSTYLE);
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return NS_OK;
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}
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/* virtual */ nsresult
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nsMathMLmsupFrame::Place(nsRenderingContext& aRenderingContext,
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bool 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 superscriptshift attribute is there
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nsAutoString value;
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nscoord supScriptShift = 0;
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GetAttribute(mContent, mPresentationData.mstyle,
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nsGkAtoms::superscriptshift_, 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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supScriptShift = CalcLength(PresContext(), mStyleContext, cssValue);
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}
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}
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return nsMathMLmsupFrame::PlaceSuperScript(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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supScriptShift,
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scriptSpace);
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}
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// exported routine that both mover and msup share.
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// mover uses this when movablelimits is set.
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nsresult
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nsMathMLmsupFrame::PlaceSuperScript(nsPresContext* aPresContext,
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nsRenderingContext& aRenderingContext,
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bool aPlaceOrigin,
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nsHTMLReflowMetrics& aDesiredSize,
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nsMathMLContainerFrame* aFrame,
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nscoord aUserSupScriptShift,
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nscoord aScriptSpace)
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{
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// force the scriptSpace to be at least 1 pixel
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nscoord onePixel = nsPresContext::CSSPixelsToAppUnits(1);
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aScriptSpace = NS_MAX(onePixel, aScriptSpace);
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////////////////////////////////////
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// Get the children's desired sizes
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nsHTMLReflowMetrics baseSize;
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nsHTMLReflowMetrics supScriptSize;
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nsBoundingMetrics bmBase, bmSupScript;
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nsIFrame* supScriptFrame = nsnull;
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nsIFrame* baseFrame = aFrame->GetFirstPrincipalChild();
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if (baseFrame)
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supScriptFrame = baseFrame->GetNextSibling();
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if (!baseFrame || !supScriptFrame || supScriptFrame->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(supScriptFrame, supScriptSize, bmSupScript);
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// get the supdrop from the supscript font
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nscoord supDrop;
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GetSupDropFromChild(supScriptFrame, supDrop);
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// parameter u, Rule 18a, App. G, TeXbook
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nscoord minSupScriptShift = bmBase.ascent - supDrop;
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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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nsRefPtr<nsFontMetrics> fm;
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nsLayoutUtils::GetFontMetricsForFrame(baseFrame, getter_AddRefs(fm));
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xHeight = fm->XHeight();
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nscoord minShiftFromXHeight = (nscoord)
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(bmSupScript.descent + (1.0f/4.0f) * xHeight);
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nscoord italicCorrection;
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GetItalicCorrection(bmBase, italicCorrection);
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// supScriptShift{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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// supScriptShift1 = 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 supScriptShift1, supScriptShift2, supScriptShift3;
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// Set supScriptShift{1,2,3} default from font
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GetSupScriptShifts (fm, supScriptShift1, supScriptShift2, supScriptShift3);
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if (0 < aUserSupScriptShift) {
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// the user has set the superscriptshift attribute
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float scaler2 = ((float) supScriptShift2) / supScriptShift1;
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float scaler3 = ((float) supScriptShift3) / supScriptShift1;
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supScriptShift1 =
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NS_MAX(supScriptShift1, aUserSupScriptShift);
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supScriptShift2 = NSToCoordRound(scaler2 * supScriptShift1);
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supScriptShift3 = NSToCoordRound(scaler3 * supScriptShift1);
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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 supScriptShift;
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nsPresentationData presentationData;
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aFrame->GetPresentationData (presentationData);
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if ( aFrame->GetStyleFont()->mScriptLevel == 0 &&
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NS_MATHML_IS_DISPLAYSTYLE(presentationData.flags) &&
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!NS_MATHML_IS_COMPRESSED(presentationData.flags)) {
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// Style D in TeXbook
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supScriptShift = supScriptShift1;
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}
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else if (NS_MATHML_IS_COMPRESSED(presentationData.flags)) {
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// Style C' in TeXbook = D',T',S',SS'
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supScriptShift = supScriptShift3;
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}
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else {
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// everything else = T,S,SS
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supScriptShift = supScriptShift2;
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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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NS_MAX(minSupScriptShift,NS_MAX(supScriptShift,minShiftFromXHeight));
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// bounding box
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nsBoundingMetrics boundingMetrics;
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boundingMetrics.ascent =
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NS_MAX(bmBase.ascent, (bmSupScript.ascent + actualSupScriptShift));
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boundingMetrics.descent =
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NS_MAX(bmBase.descent, (bmSupScript.descent - actualSupScriptShift));
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// leave aScriptSpace after superscript
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// add italicCorrection between base and superscript
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// add "a little to spare" as well (see TeXbook Ch.11, p.64), as we
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// estimate the italic creation ourselves and it isn't the same as TeX
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italicCorrection += onePixel;
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boundingMetrics.width = bmBase.width + italicCorrection +
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bmSupScript.width + aScriptSpace;
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boundingMetrics.leftBearing = bmBase.leftBearing;
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boundingMetrics.rightBearing = bmBase.width + italicCorrection +
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bmSupScript.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, (supScriptSize.ascent + actualSupScriptShift));
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aDesiredSize.height = aDesiredSize.ascent +
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NS_MAX(baseSize.height - baseSize.ascent,
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(supScriptSize.height - supScriptSize.ascent - actualSupScriptShift));
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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 supscript
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dx = bmBase.width + italicCorrection;
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dy = aDesiredSize.ascent - (supScriptSize.ascent + actualSupScriptShift);
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FinishReflowChild (supScriptFrame, aPresContext, nsnull, supScriptSize, dx, dy, 0);
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}
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return NS_OK;
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}
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