LCOV - code coverage report
Current view: directory - layout/mathml - nsMathMLmsubsupFrame.cpp (source / functions) Found Hit Coverage
Test: app.info Lines: 111 0 0.0 %
Date: 2012-06-02 Functions: 8 0 0.0 %

       1                 : /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
       2                 : /* ***** BEGIN LICENSE BLOCK *****
       3                 :  * Version: MPL 1.1/GPL 2.0/LGPL 2.1
       4                 :  *
       5                 :  * The contents of this file are subject to the Mozilla Public License Version
       6                 :  * 1.1 (the "License"); you may not use this file except in compliance with
       7                 :  * the License. You may obtain a copy of the License at
       8                 :  * http://www.mozilla.org/MPL/
       9                 :  *
      10                 :  * Software distributed under the License is distributed on an "AS IS" basis,
      11                 :  * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
      12                 :  * for the specific language governing rights and limitations under the
      13                 :  * License.
      14                 :  *
      15                 :  * The Original Code is Mozilla MathML Project.
      16                 :  *
      17                 :  * The Initial Developer of the Original Code is
      18                 :  * The University Of Queensland.
      19                 :  * Portions created by the Initial Developer are Copyright (C) 1999
      20                 :  * the Initial Developer. All Rights Reserved.
      21                 :  *
      22                 :  * Contributor(s):
      23                 :  *   Roger B. Sidje <rbs@maths.uq.edu.au>
      24                 :  *   David J. Fiddes <D.J.Fiddes@hw.ac.uk>
      25                 :  *   Shyjan Mahamud <mahamud@cs.cmu.edu> (added TeX rendering rules)
      26                 :  *
      27                 :  * Alternatively, the contents of this file may be used under the terms of
      28                 :  * either of the GNU General Public License Version 2 or later (the "GPL"),
      29                 :  * or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
      30                 :  * in which case the provisions of the GPL or the LGPL are applicable instead
      31                 :  * of those above. If you wish to allow use of your version of this file only
      32                 :  * under the terms of either the GPL or the LGPL, and not to allow others to
      33                 :  * use your version of this file under the terms of the MPL, indicate your
      34                 :  * decision by deleting the provisions above and replace them with the notice
      35                 :  * and other provisions required by the GPL or the LGPL. If you do not delete
      36                 :  * the provisions above, a recipient may use your version of this file under
      37                 :  * the terms of any one of the MPL, the GPL or the LGPL.
      38                 :  *
      39                 :  * ***** END LICENSE BLOCK ***** */
      40                 : 
      41                 : 
      42                 : #include "nsCOMPtr.h"
      43                 : #include "nsFrame.h"
      44                 : #include "nsPresContext.h"
      45                 : #include "nsStyleContext.h"
      46                 : #include "nsStyleConsts.h"
      47                 : #include "nsRenderingContext.h"
      48                 : 
      49                 : #include "nsMathMLmsubsupFrame.h"
      50                 : 
      51                 : //
      52                 : // <msubsup> -- attach a subscript-superscript pair to a base - implementation
      53                 : //
      54                 : 
      55                 : nsIFrame*
      56               0 : NS_NewMathMLmsubsupFrame(nsIPresShell* aPresShell, nsStyleContext* aContext)
      57                 : {
      58               0 :   return new (aPresShell) nsMathMLmsubsupFrame(aContext);
      59                 : }
      60                 : 
      61               0 : NS_IMPL_FRAMEARENA_HELPERS(nsMathMLmsubsupFrame)
      62                 : 
      63               0 : nsMathMLmsubsupFrame::~nsMathMLmsubsupFrame()
      64                 : {
      65               0 : }
      66                 : 
      67                 : NS_IMETHODIMP
      68               0 : nsMathMLmsubsupFrame::TransmitAutomaticData()
      69                 : {
      70                 :   // if our base is an embellished operator, let its state bubble to us
      71               0 :   mPresentationData.baseFrame = mFrames.FirstChild();
      72               0 :   GetEmbellishDataFrom(mPresentationData.baseFrame, mEmbellishData);
      73                 : 
      74                 :   // 1. The REC says:
      75                 :   //    The <msubsup> element increments scriptlevel by 1, and sets displaystyle to
      76                 :   //    "false", within subscript and superscript, but leaves both attributes
      77                 :   //    unchanged within base.
      78                 :   // 2. The TeXbook (Ch 17. p.141) says the superscript inherits the compression
      79                 :   //    while the subscript is compressed
      80                 :   UpdatePresentationDataFromChildAt(1, -1,
      81                 :     ~NS_MATHML_DISPLAYSTYLE,
      82               0 :      NS_MATHML_DISPLAYSTYLE);
      83                 :   UpdatePresentationDataFromChildAt(1,  1,
      84                 :      NS_MATHML_COMPRESSED,
      85               0 :      NS_MATHML_COMPRESSED);
      86                 : 
      87               0 :   return NS_OK;
      88                 : }
      89                 : 
      90                 : /* virtual */ nsresult
      91               0 : nsMathMLmsubsupFrame::Place(nsRenderingContext& aRenderingContext,
      92                 :                             bool                 aPlaceOrigin,
      93                 :                             nsHTMLReflowMetrics& aDesiredSize)
      94                 : {
      95                 :   // extra spacing between base and sup/subscript
      96               0 :   nscoord scriptSpace = 0;
      97                 : 
      98                 :   // check if the subscriptshift attribute is there
      99               0 :   nsAutoString value;
     100               0 :   nscoord subScriptShift = 0;
     101                 :   GetAttribute(mContent, mPresentationData.mstyle,
     102               0 :                nsGkAtoms::subscriptshift_, value);
     103               0 :   if (!value.IsEmpty()) {
     104               0 :     nsCSSValue cssValue;
     105               0 :     if (ParseNumericValue(value, cssValue) && cssValue.IsLengthUnit()) {
     106               0 :       subScriptShift = CalcLength(PresContext(), mStyleContext, cssValue);
     107                 :     }
     108                 :   }
     109                 :   // check if the superscriptshift attribute is there
     110               0 :   nscoord supScriptShift = 0;
     111                 :   GetAttribute(mContent, mPresentationData.mstyle,
     112               0 :                nsGkAtoms::superscriptshift_, value);
     113               0 :   if (!value.IsEmpty()) {
     114               0 :     nsCSSValue cssValue;
     115               0 :     if (ParseNumericValue(value, cssValue) && cssValue.IsLengthUnit()) {
     116               0 :       supScriptShift = CalcLength(PresContext(), mStyleContext, cssValue);
     117                 :     }
     118                 :   }
     119                 : 
     120                 :   return nsMathMLmsubsupFrame::PlaceSubSupScript(PresContext(),
     121                 :                                                  aRenderingContext,
     122                 :                                                  aPlaceOrigin,
     123                 :                                                  aDesiredSize,
     124                 :                                                  this,
     125                 :                                                  subScriptShift,
     126                 :                                                  supScriptShift,
     127               0 :                                                  scriptSpace);
     128                 : }
     129                 : 
     130                 : // exported routine that both munderover and msubsup share.
     131                 : // munderover uses this when movablelimits is set.
     132                 : nsresult
     133               0 : nsMathMLmsubsupFrame::PlaceSubSupScript(nsPresContext*      aPresContext,
     134                 :                                         nsRenderingContext& aRenderingContext,
     135                 :                                         bool                 aPlaceOrigin,
     136                 :                                         nsHTMLReflowMetrics& aDesiredSize,
     137                 :                                         nsMathMLContainerFrame* aFrame,
     138                 :                                         nscoord              aUserSubScriptShift,
     139                 :                                         nscoord              aUserSupScriptShift,
     140                 :                                         nscoord              aScriptSpace)
     141                 : {
     142                 :   // force the scriptSpace to be atleast 1 pixel
     143               0 :   nscoord onePixel = nsPresContext::CSSPixelsToAppUnits(1);
     144               0 :   aScriptSpace = NS_MAX(onePixel, aScriptSpace);
     145                 : 
     146                 :   ////////////////////////////////////
     147                 :   // Get the children's desired sizes
     148                 : 
     149               0 :   nsHTMLReflowMetrics baseSize;
     150               0 :   nsHTMLReflowMetrics subScriptSize;
     151               0 :   nsHTMLReflowMetrics supScriptSize;
     152               0 :   nsBoundingMetrics bmBase, bmSubScript, bmSupScript;
     153               0 :   nsIFrame* subScriptFrame = nsnull;
     154               0 :   nsIFrame* supScriptFrame = nsnull;
     155               0 :   nsIFrame* baseFrame = aFrame->GetFirstPrincipalChild();
     156               0 :   if (baseFrame)
     157               0 :     subScriptFrame = baseFrame->GetNextSibling();
     158               0 :   if (subScriptFrame)
     159               0 :     supScriptFrame = subScriptFrame->GetNextSibling();
     160               0 :   if (!baseFrame || !subScriptFrame || !supScriptFrame ||
     161               0 :       supScriptFrame->GetNextSibling()) {
     162                 :     // report an error, encourage people to get their markups in order
     163               0 :     return aFrame->ReflowError(aRenderingContext, aDesiredSize);
     164                 :   }
     165               0 :   GetReflowAndBoundingMetricsFor(baseFrame, baseSize, bmBase);
     166               0 :   GetReflowAndBoundingMetricsFor(subScriptFrame, subScriptSize, bmSubScript);
     167               0 :   GetReflowAndBoundingMetricsFor(supScriptFrame, supScriptSize, bmSupScript);
     168                 : 
     169                 :   // get the subdrop from the subscript font
     170                 :   nscoord subDrop;
     171               0 :   GetSubDropFromChild(subScriptFrame, subDrop);
     172                 :   // parameter v, Rule 18a, App. G, TeXbook
     173               0 :   nscoord minSubScriptShift = bmBase.descent + subDrop;
     174                 : 
     175                 :   // get the supdrop from the supscript font
     176                 :   nscoord supDrop;
     177               0 :   GetSupDropFromChild(supScriptFrame, supDrop);
     178                 :   // parameter u, Rule 18a, App. G, TeXbook
     179               0 :   nscoord minSupScriptShift = bmBase.ascent - supDrop;
     180                 : 
     181                 :   //////////////////
     182                 :   // Place Children
     183                 :   //////////////////
     184                 : 
     185                 :   //////////////////////////////////////////////////
     186                 :   // Get subscript shift
     187                 :   // slightly different from nsMathMLmsubFrame.cpp
     188                 :   //////////////////////////////////////////////////
     189                 : 
     190                 :   // subScriptShift{1,2}
     191                 :   // = minimum amount to shift the subscript down
     192                 :   // = sub{1,2} in TeXbook
     193                 :   // subScriptShift1 = subscriptshift attribute * x-height
     194                 :   nscoord subScriptShift1, subScriptShift2;
     195                 : 
     196               0 :   nsRefPtr<nsFontMetrics> fm;
     197               0 :   nsLayoutUtils::GetFontMetricsForFrame(baseFrame, getter_AddRefs(fm));
     198               0 :   aRenderingContext.SetFont(fm);
     199                 : 
     200                 :   // get x-height (an ex)
     201               0 :   nscoord xHeight = fm->XHeight();
     202                 : 
     203                 :   nscoord ruleSize;
     204               0 :   GetRuleThickness (aRenderingContext, fm, ruleSize);
     205                 : 
     206                 :   // Get subScriptShift{1,2} default from font
     207               0 :   GetSubScriptShifts (fm, subScriptShift1, subScriptShift2);
     208                 : 
     209               0 :   if (0 < aUserSubScriptShift) {
     210                 :     // the user has set the subscriptshift attribute
     211               0 :     float scaler = ((float) subScriptShift2) / subScriptShift1;
     212               0 :     subScriptShift1 = NS_MAX(subScriptShift1, aUserSubScriptShift);
     213               0 :     subScriptShift2 = NSToCoordRound(scaler * subScriptShift1);
     214                 :   }
     215                 : 
     216                 :   // get a tentative value for subscriptshift
     217                 :   // Rule 18d, App. G, TeXbook
     218                 :   nscoord subScriptShift =
     219               0 :     NS_MAX(minSubScriptShift,NS_MAX(subScriptShift1,subScriptShift2));
     220                 : 
     221                 :   //////////////////////////////////////////////////
     222                 :   // Get supscript shift
     223                 :   // same code from nsMathMLmsupFrame.cpp
     224                 :   //////////////////////////////////////////////////
     225                 : 
     226                 :   // get min supscript shift limit from x-height
     227                 :   // = d(x) + 1/4 * sigma_5, Rule 18c, App. G, TeXbook
     228                 :   nscoord minShiftFromXHeight = (nscoord)
     229               0 :     (bmSupScript.descent + (1.0f/4.0f) * xHeight);
     230                 : 
     231                 :   // supScriptShift{1,2,3}
     232                 :   // = minimum amount to shift the supscript up
     233                 :   // = sup{1,2,3} in TeX
     234                 :   // supScriptShift1 = superscriptshift attribute * x-height
     235                 :   // Note that there are THREE values for supscript shifts depending
     236                 :   // on the current style
     237                 :   nscoord supScriptShift1, supScriptShift2, supScriptShift3;
     238                 :   // Set supScriptShift{1,2,3} default from font
     239               0 :   GetSupScriptShifts (fm, supScriptShift1, supScriptShift2, supScriptShift3);
     240               0 :   if (0 < aUserSupScriptShift) {
     241                 :     // the user has set the superscriptshift attribute
     242               0 :     float scaler2 = ((float) supScriptShift2) / supScriptShift1;
     243               0 :     float scaler3 = ((float) supScriptShift3) / supScriptShift1;
     244               0 :     supScriptShift1 = NS_MAX(supScriptShift1, aUserSupScriptShift);
     245               0 :     supScriptShift2 = NSToCoordRound(scaler2 * supScriptShift1);
     246               0 :     supScriptShift3 = NSToCoordRound(scaler3 * supScriptShift1);
     247                 :   }
     248                 : 
     249                 :   // get sup script shift depending on current script level and display style
     250                 :   // Rule 18c, App. G, TeXbook
     251                 :   nscoord supScriptShift;
     252               0 :   nsPresentationData presentationData;
     253               0 :   aFrame->GetPresentationData(presentationData);
     254               0 :   if ( aFrame->GetStyleFont()->mScriptLevel == 0 &&
     255                 :        NS_MATHML_IS_DISPLAYSTYLE(presentationData.flags) &&
     256               0 :       !NS_MATHML_IS_COMPRESSED(presentationData.flags)) {
     257                 :     // Style D in TeXbook
     258               0 :     supScriptShift = supScriptShift1;
     259                 :   }
     260               0 :   else if (NS_MATHML_IS_COMPRESSED(presentationData.flags)) {
     261                 :     // Style C' in TeXbook = D',T',S',SS'
     262               0 :     supScriptShift = supScriptShift3;
     263                 :   }
     264                 :   else {
     265                 :     // everything else = T,S,SS
     266               0 :     supScriptShift = supScriptShift2;
     267                 :   }
     268                 : 
     269                 :   // get tentative value for superscriptshift
     270                 :   // Rule 18c, App. G, TeXbook
     271                 :   supScriptShift =
     272               0 :     NS_MAX(minSupScriptShift,NS_MAX(supScriptShift,minShiftFromXHeight));
     273                 : 
     274                 :   //////////////////////////////////////////////////
     275                 :   // Negotiate between supScriptShift and subScriptShift
     276                 :   // so that there will be enough gap between them
     277                 :   // Rule 18e, App. G, TeXbook
     278                 :   //////////////////////////////////////////////////
     279                 : 
     280                 :   nscoord gap =
     281                 :     (supScriptShift - bmSupScript.descent) -
     282               0 :     (bmSubScript.ascent - subScriptShift);
     283               0 :   if (gap < 4.0f * ruleSize) {
     284                 :     // adjust subScriptShift to get a gap of (4.0 * ruleSize)
     285               0 :     subScriptShift += NSToCoordRound ((4.0f * ruleSize) - gap);
     286                 :   }
     287                 : 
     288                 :   // next we want to ensure that the bottom of the superscript
     289                 :   // will be > (4/5) * x-height above baseline
     290                 :   gap = NSToCoordRound ((4.0f/5.0f) * xHeight -
     291               0 :                         (supScriptShift - bmSupScript.descent));
     292               0 :   if (gap > 0) {
     293               0 :     supScriptShift += gap;
     294               0 :     subScriptShift -= gap;
     295                 :   }
     296                 : 
     297                 :   //////////////////////////////////////////////////
     298                 :   // Do the Placing
     299                 :   //////////////////////////////////////////////////
     300                 : 
     301                 :   // get bounding box for base + subscript + superscript
     302               0 :   nsBoundingMetrics boundingMetrics;
     303                 :   boundingMetrics.ascent =
     304               0 :     NS_MAX(bmBase.ascent, (bmSupScript.ascent + supScriptShift));
     305                 :   boundingMetrics.descent =
     306               0 :    NS_MAX(bmBase.descent, (bmSubScript.descent + subScriptShift));
     307                 : 
     308                 :   // leave aScriptSpace after both super/subscript
     309                 :   // add italicCorrection between base and superscript
     310                 :   // add "a little to spare" as well (see TeXbook Ch.11, p.64), as we
     311                 :   // estimate the italic creation ourselves and it isn't the same as TeX 
     312                 :   nscoord italicCorrection;
     313               0 :   GetItalicCorrection(bmBase, italicCorrection);
     314               0 :   italicCorrection += onePixel;
     315                 :   boundingMetrics.width = bmBase.width + aScriptSpace +
     316               0 :     NS_MAX((italicCorrection + bmSupScript.width), bmSubScript.width);
     317               0 :   boundingMetrics.leftBearing = bmBase.leftBearing;
     318                 :   boundingMetrics.rightBearing = bmBase.width +
     319               0 :     NS_MAX((italicCorrection + bmSupScript.rightBearing), bmSubScript.rightBearing);
     320               0 :   aFrame->SetBoundingMetrics(boundingMetrics);
     321                 : 
     322                 :   // reflow metrics
     323                 :   aDesiredSize.ascent =
     324                 :     NS_MAX(baseSize.ascent, 
     325                 :        NS_MAX(subScriptSize.ascent - subScriptShift,
     326               0 :               supScriptSize.ascent + supScriptShift));
     327                 :   aDesiredSize.height = aDesiredSize.ascent +
     328                 :     NS_MAX(baseSize.height - baseSize.ascent,
     329                 :        NS_MAX(subScriptSize.height - subScriptSize.ascent + subScriptShift, 
     330               0 :               supScriptSize.height - subScriptSize.ascent - supScriptShift));
     331               0 :   aDesiredSize.width = boundingMetrics.width;
     332               0 :   aDesiredSize.mBoundingMetrics = boundingMetrics;
     333                 : 
     334               0 :   aFrame->SetReference(nsPoint(0, aDesiredSize.ascent));
     335                 : 
     336               0 :   if (aPlaceOrigin) {
     337                 :     nscoord dx, dy;
     338                 :     // now place the base ...
     339               0 :     dx = aFrame->MirrorIfRTL(aDesiredSize.width, baseSize.width, 0);
     340               0 :     dy = aDesiredSize.ascent - baseSize.ascent;
     341                 :     FinishReflowChild(baseFrame, aPresContext, nsnull,
     342               0 :                       baseSize, dx, dy, 0);
     343                 :     // ... and subscript
     344                 :     dx = aFrame->MirrorIfRTL(aDesiredSize.width, subScriptSize.width,
     345               0 :                              bmBase.width);
     346               0 :     dy = aDesiredSize.ascent - (subScriptSize.ascent - subScriptShift);
     347                 :     FinishReflowChild(subScriptFrame, aPresContext, nsnull,
     348               0 :                       subScriptSize, dx, dy, 0);
     349                 :     // ... and the superscript
     350                 :     dx = aFrame->MirrorIfRTL(aDesiredSize.width, supScriptSize.width,
     351               0 :                              bmBase.width + italicCorrection);
     352               0 :     dy = aDesiredSize.ascent - (supScriptSize.ascent + supScriptShift);
     353                 :     FinishReflowChild(supScriptFrame, aPresContext, nsnull,
     354               0 :                       supScriptSize, dx, dy, 0);
     355                 :   }
     356                 : 
     357               0 :   return NS_OK;
     358                 : }

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