DXR is a code search and navigation tool aimed at making sense of large projects. It supports full-text and regex searches as well as structural queries.

Mercurial (3865bf230c49)

VCS Links

Line Code
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255
/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* ***** BEGIN LICENSE BLOCK *****
 * Version: MPL 1.1/GPL 2.0/LGPL 2.1
 *
 * The contents of this file are subject to the Mozilla Public License Version
 * 1.1 (the "License"); you may not use this file except in compliance with
 * the License. You may obtain a copy of the License at
 * http://www.mozilla.org/MPL/
 *
 * Software distributed under the License is distributed on an "AS IS" basis,
 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
 * for the specific language governing rights and limitations under the
 * License.
 *
 * The Original Code is Mozilla MathML Project.
 *
 * The Initial Developer of the Original Code is
 * The University Of Queensland.
 * Portions created by the Initial Developer are Copyright (C) 1999
 * the Initial Developer. All Rights Reserved.
 *
 * Contributor(s):
 *   Roger B. Sidje <rbs@maths.uq.edu.au>
 *   David J. Fiddes <D.J.Fiddes@hw.ac.uk>
 *   Shyjan Mahamud <mahamud@cs.cmu.edu> (added TeX rendering rules)
 *
 * Alternatively, the contents of this file may be used under the terms of
 * either of the GNU General Public License Version 2 or later (the "GPL"),
 * or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
 * in which case the provisions of the GPL or the LGPL are applicable instead
 * of those above. If you wish to allow use of your version of this file only
 * under the terms of either the GPL or the LGPL, and not to allow others to
 * use your version of this file under the terms of the MPL, indicate your
 * decision by deleting the provisions above and replace them with the notice
 * and other provisions required by the GPL or the LGPL. If you do not delete
 * the provisions above, a recipient may use your version of this file under
 * the terms of any one of the MPL, the GPL or the LGPL.
 *
 * ***** END LICENSE BLOCK ***** */

#include "nsCOMPtr.h"
#include "nsFrame.h"
#include "nsPresContext.h"
#include "nsStyleContext.h"
#include "nsStyleConsts.h"
#include "nsIRenderingContext.h"
#include "nsIFontMetrics.h"

#include "nsMathMLmsupFrame.h"

//
// <msup> -- attach a superscript to a base - implementation
//

nsIFrame*
NS_NewMathMLmsupFrame(nsIPresShell* aPresShell, nsStyleContext* aContext)
{
  return new (aPresShell) nsMathMLmsupFrame(aContext);
}

NS_IMPL_FRAMEARENA_HELPERS(nsMathMLmsupFrame)

nsMathMLmsupFrame::~nsMathMLmsupFrame()
{
}

NS_IMETHODIMP
nsMathMLmsupFrame::TransmitAutomaticData()
{
  // if our base is an embellished operator, its flags bubble to us
  mPresentationData.baseFrame = mFrames.FirstChild();
  GetEmbellishDataFrom(mPresentationData.baseFrame, mEmbellishData);

  // 1. The REC says:
  // The <msup> element increments scriptlevel by 1, and sets displaystyle to
  // "false", within superscript, but leaves both attributes unchanged within base.
  // 2. The TeXbook (Ch 17. p.141) says the superscript *inherits* the compression,
  // so we don't set the compression flag. Our parent will propagate its own.
  UpdatePresentationDataFromChildAt(1, -1,
    ~NS_MATHML_DISPLAYSTYLE,
     NS_MATHML_DISPLAYSTYLE);

  return NS_OK;
}

/* virtual */ nsresult
nsMathMLmsupFrame::Place(nsIRenderingContext& aRenderingContext,
                         PRBool               aPlaceOrigin,
                         nsHTMLReflowMetrics& aDesiredSize)
{
  // extra spacing after sup/subscript
  nscoord scriptSpace = PresContext()->PointsToAppUnits(0.5f); // 0.5pt as in plain TeX

  // check if the superscriptshift attribute is there
  nsAutoString value;
  nscoord supScriptShift = 0;
  GetAttribute(mContent, mPresentationData.mstyle,
               nsGkAtoms::superscriptshift_, value);
  if (!value.IsEmpty()) {
    nsCSSValue cssValue;
    if (ParseNumericValue(value, cssValue) && cssValue.IsLengthUnit()) {
      supScriptShift = CalcLength(PresContext(), mStyleContext, cssValue);
    }
  }

  return nsMathMLmsupFrame::PlaceSuperScript(PresContext(), 
                                             aRenderingContext,
                                             aPlaceOrigin,
                                             aDesiredSize,
                                             this,
                                             supScriptShift,
                                             scriptSpace);
}

// exported routine that both mover and msup share.
// mover uses this when movablelimits is set.
nsresult
nsMathMLmsupFrame::PlaceSuperScript(nsPresContext*      aPresContext,
                                    nsIRenderingContext& aRenderingContext,
                                    PRBool               aPlaceOrigin,
                                    nsHTMLReflowMetrics& aDesiredSize,
                                    nsMathMLContainerFrame* aFrame,
                                    nscoord              aUserSupScriptShift,
                                    nscoord              aScriptSpace)
{
  // force the scriptSpace to be at least 1 pixel 
  nscoord onePixel = nsPresContext::CSSPixelsToAppUnits(1);
  aScriptSpace = NS_MAX(onePixel, aScriptSpace);

  ////////////////////////////////////
  // Get the children's desired sizes

  nsHTMLReflowMetrics baseSize;
  nsHTMLReflowMetrics supScriptSize;
  nsBoundingMetrics bmBase, bmSupScript;
  nsIFrame* supScriptFrame = nsnull;
  nsIFrame* baseFrame = aFrame->GetFirstChild(nsnull);
  if (baseFrame)
    supScriptFrame = baseFrame->GetNextSibling();
  if (!baseFrame || !supScriptFrame || supScriptFrame->GetNextSibling()) {
    // report an error, encourage people to get their markups in order
    return aFrame->ReflowError(aRenderingContext, aDesiredSize);
  }
  GetReflowAndBoundingMetricsFor(baseFrame, baseSize, bmBase);
  GetReflowAndBoundingMetricsFor(supScriptFrame, supScriptSize, bmSupScript);

  // get the supdrop from the supscript font
  nscoord supDrop;
  GetSupDropFromChild(supScriptFrame, supDrop);
  // parameter u, Rule 18a, App. G, TeXbook
  nscoord minSupScriptShift = bmBase.ascent - supDrop;

  //////////////////
  // Place Children 
  
  // get min supscript shift limit from x-height
  // = d(x) + 1/4 * sigma_5, Rule 18c, App. G, TeXbook
  nscoord xHeight = 0;
  nsCOMPtr<nsIFontMetrics> fm =
    aPresContext->GetMetricsFor(baseFrame->GetStyleFont()->mFont);

  fm->GetXHeight (xHeight);
  nscoord minShiftFromXHeight = (nscoord) 
    (bmSupScript.descent + (1.0f/4.0f) * xHeight);
  nscoord italicCorrection;
  GetItalicCorrection(bmBase, italicCorrection);

  // supScriptShift{1,2,3}
  // = minimum amount to shift the supscript up
  // = sup{1,2,3} in TeX
  // supScriptShift1 = superscriptshift attribute * x-height
  // Note that there are THREE values for supscript shifts depending
  // on the current style
  nscoord supScriptShift1, supScriptShift2, supScriptShift3;
  // Set supScriptShift{1,2,3} default from font
  GetSupScriptShifts (fm, supScriptShift1, supScriptShift2, supScriptShift3);

  if (0 < aUserSupScriptShift) {
    // the user has set the superscriptshift attribute
    float scaler2 = ((float) supScriptShift2) / supScriptShift1;
    float scaler3 = ((float) supScriptShift3) / supScriptShift1;
    supScriptShift1 = 
      NS_MAX(supScriptShift1, aUserSupScriptShift);
    supScriptShift2 = NSToCoordRound(scaler2 * supScriptShift1);
    supScriptShift3 = NSToCoordRound(scaler3 * supScriptShift1);
  }

  // get sup script shift depending on current script level and display style
  // Rule 18c, App. G, TeXbook
  nscoord supScriptShift;
  nsPresentationData presentationData;
  aFrame->GetPresentationData (presentationData);
  if ( aFrame->GetStyleFont()->mScriptLevel == 0 && 
       NS_MATHML_IS_DISPLAYSTYLE(presentationData.flags) &&
      !NS_MATHML_IS_COMPRESSED(presentationData.flags)) {
    // Style D in TeXbook
    supScriptShift = supScriptShift1;
  }
  else if (NS_MATHML_IS_COMPRESSED(presentationData.flags)) {
    // Style C' in TeXbook = D',T',S',SS'
    supScriptShift = supScriptShift3;
  }
  else {
    // everything else = T,S,SS
    supScriptShift = supScriptShift2;
  }

  // get actual supscriptshift to be used
  // Rule 18c, App. G, TeXbook
  nscoord actualSupScriptShift = 
    NS_MAX(minSupScriptShift,NS_MAX(supScriptShift,minShiftFromXHeight));

  // bounding box
  nsBoundingMetrics boundingMetrics;
  boundingMetrics.ascent =
    NS_MAX(bmBase.ascent, (bmSupScript.ascent + actualSupScriptShift));
  boundingMetrics.descent =
    NS_MAX(bmBase.descent, (bmSupScript.descent - actualSupScriptShift));

  // leave aScriptSpace after superscript
  // add italicCorrection between base and superscript
  // add "a little to spare" as well (see TeXbook Ch.11, p.64), as we
  // estimate the italic creation ourselves and it isn't the same as TeX 
  italicCorrection += onePixel;
  boundingMetrics.width = bmBase.width + italicCorrection +
                          bmSupScript.width + aScriptSpace;
  boundingMetrics.leftBearing = bmBase.leftBearing;
  boundingMetrics.rightBearing = bmBase.width + italicCorrection +
                                 bmSupScript.rightBearing;
  aFrame->SetBoundingMetrics(boundingMetrics);

  // reflow metrics
  aDesiredSize.ascent =
    NS_MAX(baseSize.ascent, (supScriptSize.ascent + actualSupScriptShift));
  aDesiredSize.height = aDesiredSize.ascent +
    NS_MAX(baseSize.height - baseSize.ascent,
           (supScriptSize.height - supScriptSize.ascent - actualSupScriptShift));
  aDesiredSize.width = boundingMetrics.width;
  aDesiredSize.mBoundingMetrics = boundingMetrics;

  aFrame->SetReference(nsPoint(0, aDesiredSize.ascent));

  if (aPlaceOrigin) {
    nscoord dx, dy;
    // now place the base ...
    dx = 0; dy = aDesiredSize.ascent - baseSize.ascent;
    FinishReflowChild (baseFrame, aPresContext, nsnull, baseSize, dx, dy, 0);
    // ... and supscript
    dx = bmBase.width + italicCorrection;
    dy = aDesiredSize.ascent - (supScriptSize.ascent + actualSupScriptShift);
    FinishReflowChild (supScriptFrame, aPresContext, nsnull, supScriptSize, dx, dy, 0);
  }

  return NS_OK;
}