The Tor Browser: layout/mathml/nsMathMLmencloseFrame.cpp@b8a032363ba2 (annotated)

layout/mathml/nsMathMLmencloseFrame.cpp@b8a032363ba2 (annotated)

layout/mathml/nsMathMLmencloseFrame.cpp

Thu, 22 Jan 2015 13:21:57 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Thu, 22 Jan 2015 13:21:57 +0100
branch: TOR_BUG_9701
changeset 15: b8a032363ba2
permissions: -rw-r--r--

Incorporate requested changes from Mozilla in review:
https://bugzilla.mozilla.org/show_bug.cgi?id=1123480#c6

 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
 /* This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 #include "nsMathMLmencloseFrame.h"
 #include "nsPresContext.h"
 #include "nsRenderingContext.h"
 #include "nsWhitespaceTokenizer.h"
 #include "nsDisplayList.h"
 #include "gfxContext.h"
 #include "nsMathMLChar.h"
 #include <algorithm>
 //
 // <menclose> -- enclose content with a stretching symbol such
 // as a long division sign. - implementation
 // longdiv:
 // Unicode 5.1 assigns U+27CC to LONG DIVISION, but a right parenthesis
 // renders better with current font support.
 static const char16_t kLongDivChar = ')';
 // radical: 'SQUARE ROOT'
 static const char16_t kRadicalChar = 0x221A;
 // updiagonalstrike
 static const uint8_t kArrowHeadSize = 10;
 nsIFrame*
 NS_NewMathMLmencloseFrame(nsIPresShell* aPresShell, nsStyleContext* aContext)
 {
   return new (aPresShell) nsMathMLmencloseFrame(aContext);
 }
 NS_IMPL_FRAMEARENA_HELPERS(nsMathMLmencloseFrame)
 nsMathMLmencloseFrame::nsMathMLmencloseFrame(nsStyleContext* aContext) :
   nsMathMLContainerFrame(aContext), mNotationsToDraw(0),
   mLongDivCharIndex(-1), mRadicalCharIndex(-1), mContentWidth(0)
 {
 }
 nsMathMLmencloseFrame::~nsMathMLmencloseFrame()
 {
 }
 nsresult nsMathMLmencloseFrame::AllocateMathMLChar(nsMencloseNotation mask)
 {
   // Is the char already allocated?
   if ((mask == NOTATION_LONGDIV && mLongDivCharIndex >= 0) ||
       (mask == NOTATION_RADICAL && mRadicalCharIndex >= 0))
     return NS_OK;
   // No need to track the style context given to our MathML chars.
   // The Style System will use Get/SetAdditionalStyleContext() to keep it
   // up-to-date if dynamic changes arise.
   uint32_t i = mMathMLChar.Length();
   nsAutoString Char;
   if (!mMathMLChar.AppendElement())
     return NS_ERROR_OUT_OF_MEMORY;
   if (mask == NOTATION_LONGDIV) {
     Char.Assign(kLongDivChar);
     mLongDivCharIndex = i;
   } else if (mask == NOTATION_RADICAL) {
     Char.Assign(kRadicalChar);
     mRadicalCharIndex = i;
   }
   nsPresContext *presContext = PresContext();
   mMathMLChar[i].SetData(presContext, Char);
   ResolveMathMLCharStyle(presContext, mContent, mStyleContext, &mMathMLChar[i]);
   return NS_OK;
 }
 /*
  * Add a notation to draw, if the argument is the name of a known notation.
  * @param aNotation string name of a notation
  */
 nsresult nsMathMLmencloseFrame::AddNotation(const nsAString& aNotation)
 {
   nsresult rv;
   if (aNotation.EqualsLiteral("longdiv")) {
     rv = AllocateMathMLChar(NOTATION_LONGDIV);
     NS_ENSURE_SUCCESS(rv, rv);
     mNotationsToDraw |= NOTATION_LONGDIV;
   } else if (aNotation.EqualsLiteral("actuarial")) {
     mNotationsToDraw |= (NOTATION_RIGHT | NOTATION_TOP);
   } else if (aNotation.EqualsLiteral("radical")) {
     rv = AllocateMathMLChar(NOTATION_RADICAL);
     NS_ENSURE_SUCCESS(rv, rv);
     mNotationsToDraw |= NOTATION_RADICAL;
   } else if (aNotation.EqualsLiteral("box")) {
     mNotationsToDraw |= (NOTATION_LEFT | NOTATION_RIGHT |
                          NOTATION_TOP | NOTATION_BOTTOM);
   } else if (aNotation.EqualsLiteral("roundedbox")) {
     mNotationsToDraw |= NOTATION_ROUNDEDBOX;
   } else if (aNotation.EqualsLiteral("circle")) {
     mNotationsToDraw |= NOTATION_CIRCLE;
   } else if (aNotation.EqualsLiteral("left")) {
     mNotationsToDraw |= NOTATION_LEFT;
   } else if (aNotation.EqualsLiteral("right")) {
     mNotationsToDraw |= NOTATION_RIGHT;
   } else if (aNotation.EqualsLiteral("top")) {
     mNotationsToDraw |= NOTATION_TOP;
   } else if (aNotation.EqualsLiteral("bottom")) {
     mNotationsToDraw |= NOTATION_BOTTOM;
   } else if (aNotation.EqualsLiteral("updiagonalstrike")) {
     mNotationsToDraw |= NOTATION_UPDIAGONALSTRIKE;
   } else if (aNotation.EqualsLiteral("updiagonalarrow")) {
     mNotationsToDraw |= NOTATION_UPDIAGONALARROW;
   } else if (aNotation.EqualsLiteral("downdiagonalstrike")) {
     mNotationsToDraw |= NOTATION_DOWNDIAGONALSTRIKE;
   } else if (aNotation.EqualsLiteral("verticalstrike")) {
     mNotationsToDraw |= NOTATION_VERTICALSTRIKE;
   } else if (aNotation.EqualsLiteral("horizontalstrike")) {
     mNotationsToDraw |= NOTATION_HORIZONTALSTRIKE;
   } else if (aNotation.EqualsLiteral("madruwb")) {
     mNotationsToDraw |= (NOTATION_RIGHT | NOTATION_BOTTOM);
   }
   return NS_OK;
 }
 /*
  * Initialize the list of notations to draw
  */
 void nsMathMLmencloseFrame::InitNotations()
 {
   mNotationsToDraw = 0;
   mLongDivCharIndex = mRadicalCharIndex = -1;
   mMathMLChar.Clear();
   nsAutoString value;
   if (mContent->GetAttr(kNameSpaceID_None, nsGkAtoms::notation_, value)) {
     // parse the notation attribute
     nsWhitespaceTokenizer tokenizer(value);
     while (tokenizer.hasMoreTokens())
       AddNotation(tokenizer.nextToken());
     if (IsToDraw(NOTATION_UPDIAGONALARROW)) {
       // For <menclose notation="updiagonalstrike updiagonalarrow">, if
       // the two notations are drawn then the strike line may cause the point of
       // the arrow to be too wide. Hence we will only draw the updiagonalarrow
       // and the arrow shaft may be thought to be the updiagonalstrike.
       mNotationsToDraw &= ~NOTATION_UPDIAGONALSTRIKE;
     }
   } else {
     // default: longdiv
     if (NS_FAILED(AllocateMathMLChar(NOTATION_LONGDIV)))
       return;
     mNotationsToDraw = NOTATION_LONGDIV;
   }
 }
 NS_IMETHODIMP
 nsMathMLmencloseFrame::InheritAutomaticData(nsIFrame* aParent)
 {
   // let the base class get the default from our parent
   nsMathMLContainerFrame::InheritAutomaticData(aParent);
   mPresentationData.flags |= NS_MATHML_STRETCH_ALL_CHILDREN_VERTICALLY;
   InitNotations();
   return NS_OK;
 }
 NS_IMETHODIMP
 nsMathMLmencloseFrame::TransmitAutomaticData()
 {
   if (IsToDraw(NOTATION_RADICAL)) {
     // The TeXBook (Ch 17. p.141) says that \sqrt is cramped
     UpdatePresentationDataFromChildAt(0, -1,
                                       NS_MATHML_COMPRESSED,
                                       NS_MATHML_COMPRESSED);
   }
   return NS_OK;
 }
 void
 nsMathMLmencloseFrame::BuildDisplayList(nsDisplayListBuilder*   aBuilder,
                                         const nsRect&           aDirtyRect,
                                         const nsDisplayListSet& aLists)
 {
   /////////////
   // paint the menclosed content
   nsMathMLContainerFrame::BuildDisplayList(aBuilder, aDirtyRect, aLists);
   if (NS_MATHML_HAS_ERROR(mPresentationData.flags))
     return;
   nsRect mencloseRect = nsIFrame::GetRect();
   mencloseRect.x = mencloseRect.y = 0;
   if (IsToDraw(NOTATION_RADICAL)) {
     mMathMLChar[mRadicalCharIndex].Display(aBuilder, this, aLists, 0);
     nsRect rect;
     mMathMLChar[mRadicalCharIndex].GetRect(rect);
     rect.MoveBy(StyleVisibility()->mDirection ? -mContentWidth : rect.width, 0);
     rect.SizeTo(mContentWidth, mRuleThickness);
     DisplayBar(aBuilder, this, rect, aLists);
   }
   if (IsToDraw(NOTATION_LONGDIV)) {
     mMathMLChar[mLongDivCharIndex].Display(aBuilder, this, aLists, 1);
     nsRect rect;
     mMathMLChar[mLongDivCharIndex].GetRect(rect);
     rect.SizeTo(rect.width + mContentWidth, mRuleThickness);
     DisplayBar(aBuilder, this, rect, aLists);
   }
   if (IsToDraw(NOTATION_TOP)) {
     nsRect rect(0, 0, mencloseRect.width, mRuleThickness);
     DisplayBar(aBuilder, this, rect, aLists);
   }
   if (IsToDraw(NOTATION_BOTTOM)) {
     nsRect rect(0, mencloseRect.height - mRuleThickness,
                 mencloseRect.width, mRuleThickness);
     DisplayBar(aBuilder, this, rect, aLists);
   }
   if (IsToDraw(NOTATION_LEFT)) {
     nsRect rect(0, 0, mRuleThickness, mencloseRect.height);
     DisplayBar(aBuilder, this, rect, aLists);
   }
   if (IsToDraw(NOTATION_RIGHT)) {
     nsRect rect(mencloseRect.width - mRuleThickness, 0,
                 mRuleThickness, mencloseRect.height);
     DisplayBar(aBuilder, this, rect, aLists);
   }
   if (IsToDraw(NOTATION_ROUNDEDBOX)) {
     DisplayNotation(aBuilder, this, mencloseRect, aLists,
                     mRuleThickness, NOTATION_ROUNDEDBOX);
   }
   if (IsToDraw(NOTATION_CIRCLE)) {
     DisplayNotation(aBuilder, this, mencloseRect, aLists,
                     mRuleThickness, NOTATION_CIRCLE);
   }
   if (IsToDraw(NOTATION_UPDIAGONALSTRIKE)) {
     DisplayNotation(aBuilder, this, mencloseRect, aLists,
                     mRuleThickness, NOTATION_UPDIAGONALSTRIKE);
   }
   if (IsToDraw(NOTATION_UPDIAGONALARROW)) {
     DisplayNotation(aBuilder, this, mencloseRect, aLists,
                     mRuleThickness, NOTATION_UPDIAGONALARROW);
   }
   if (IsToDraw(NOTATION_DOWNDIAGONALSTRIKE)) {
     DisplayNotation(aBuilder, this, mencloseRect, aLists,
                     mRuleThickness, NOTATION_DOWNDIAGONALSTRIKE);
   }
   if (IsToDraw(NOTATION_HORIZONTALSTRIKE)) {
     nsRect rect(0, mencloseRect.height / 2 - mRuleThickness / 2,
                 mencloseRect.width, mRuleThickness);
     DisplayBar(aBuilder, this, rect, aLists);
   }
   if (IsToDraw(NOTATION_VERTICALSTRIKE)) {
     nsRect rect(mencloseRect.width / 2 - mRuleThickness / 2, 0,
                 mRuleThickness, mencloseRect.height);
     DisplayBar(aBuilder, this, rect, aLists);
   }
 }
 /* virtual */ nsresult
 nsMathMLmencloseFrame::MeasureForWidth(nsRenderingContext& aRenderingContext,
                                        nsHTMLReflowMetrics& aDesiredSize)
 {
   return PlaceInternal(aRenderingContext, false, aDesiredSize, true);
 }
 /* virtual */ nsresult
 nsMathMLmencloseFrame::Place(nsRenderingContext& aRenderingContext,
                              bool                 aPlaceOrigin,
                              nsHTMLReflowMetrics& aDesiredSize)
 {
   return PlaceInternal(aRenderingContext, aPlaceOrigin, aDesiredSize, false);
 }
 /* virtual */ nsresult
 nsMathMLmencloseFrame::PlaceInternal(nsRenderingContext& aRenderingContext,
                                      bool                 aPlaceOrigin,
                                      nsHTMLReflowMetrics& aDesiredSize,
                                      bool                 aWidthOnly)
 {
   ///////////////
   // Measure the size of our content using the base class to format like an
   // inferred mrow.
   nsHTMLReflowMetrics baseSize(aDesiredSize.GetWritingMode());
   nsresult rv =
     nsMathMLContainerFrame::Place(aRenderingContext, false, baseSize);
   if (NS_MATHML_HAS_ERROR(mPresentationData.flags) || NS_FAILED(rv)) {
       DidReflowChildren(GetFirstPrincipalChild());
       return rv;
     }
   nsBoundingMetrics bmBase = baseSize.mBoundingMetrics;
   nscoord dx_left = 0, dx_right = 0;
   nsBoundingMetrics bmLongdivChar, bmRadicalChar;
   nscoord radicalAscent = 0, radicalDescent = 0;
   nscoord longdivAscent = 0, longdivDescent = 0;
   nscoord psi = 0;
   ///////////////
   // Thickness of bars and font metrics
   nscoord onePixel = nsPresContext::CSSPixelsToAppUnits(1);
   nscoord mEmHeight;
   nsRefPtr<nsFontMetrics> fm;
   nsLayoutUtils::GetFontMetricsForFrame(this, getter_AddRefs(fm));
   aRenderingContext.SetFont(fm);
   GetRuleThickness(aRenderingContext, fm, mRuleThickness);
   GetEmHeight(fm, mEmHeight);
   char16_t one = '1';
   nsBoundingMetrics bmOne = aRenderingContext.GetBoundingMetrics(&one, 1);
   ///////////////
   // General rules: the menclose element takes the size of the enclosed content.
   // We add a padding when needed.
   // determine padding & psi
   nscoord padding = 3 * mRuleThickness;
   nscoord delta = padding % onePixel;
   if (delta)
     padding += onePixel - delta; // round up
   if (IsToDraw(NOTATION_LONGDIV) || IsToDraw(NOTATION_RADICAL)) {
       nscoord phi;
       // Rule 11, App. G, TeXbook
       // psi = clearance between rule and content
       if (StyleFont()->mMathDisplay == NS_MATHML_DISPLAYSTYLE_BLOCK)
         phi = fm->XHeight();
       else
         phi = mRuleThickness;
       psi = mRuleThickness + phi / 4;
       delta = psi % onePixel;
       if (delta)
         psi += onePixel - delta; // round up
     }
   if (mRuleThickness < onePixel)
     mRuleThickness = onePixel;
   // Set horizontal parameters
   if (IsToDraw(NOTATION_ROUNDEDBOX) ||
       IsToDraw(NOTATION_TOP) ||
       IsToDraw(NOTATION_LEFT) ||
       IsToDraw(NOTATION_BOTTOM) ||
       IsToDraw(NOTATION_CIRCLE))
     dx_left = padding;
   if (IsToDraw(NOTATION_ROUNDEDBOX) ||
       IsToDraw(NOTATION_TOP) ||
       IsToDraw(NOTATION_RIGHT) ||
       IsToDraw(NOTATION_BOTTOM) ||
       IsToDraw(NOTATION_CIRCLE))
     dx_right = padding;
   // Set vertical parameters
   if (IsToDraw(NOTATION_RIGHT) ||
       IsToDraw(NOTATION_LEFT) ||
       IsToDraw(NOTATION_UPDIAGONALSTRIKE) ||
       IsToDraw(NOTATION_UPDIAGONALARROW) ||
       IsToDraw(NOTATION_DOWNDIAGONALSTRIKE) ||
       IsToDraw(NOTATION_VERTICALSTRIKE) ||
       IsToDraw(NOTATION_CIRCLE) ||
       IsToDraw(NOTATION_ROUNDEDBOX) ||
       IsToDraw(NOTATION_RADICAL) ||
       IsToDraw(NOTATION_LONGDIV)) {
       // set a minimal value for the base height
       bmBase.ascent = std::max(bmOne.ascent, bmBase.ascent);
       bmBase.descent = std::max(0, bmBase.descent);
   }
   mBoundingMetrics.ascent = bmBase.ascent;
   mBoundingMetrics.descent = bmBase.descent;
   if (IsToDraw(NOTATION_ROUNDEDBOX) ||
       IsToDraw(NOTATION_TOP) ||
       IsToDraw(NOTATION_LEFT) ||
       IsToDraw(NOTATION_RIGHT) ||
       IsToDraw(NOTATION_CIRCLE))
     mBoundingMetrics.ascent += padding;
   if (IsToDraw(NOTATION_ROUNDEDBOX) ||
       IsToDraw(NOTATION_LEFT) ||
       IsToDraw(NOTATION_RIGHT) ||
       IsToDraw(NOTATION_BOTTOM) ||
       IsToDraw(NOTATION_CIRCLE))
     mBoundingMetrics.descent += padding;
   ///////////////
   // updiagonal arrow notation. We need enough space at the top right corner to
   // draw the arrow head.
   if (IsToDraw(NOTATION_UPDIAGONALARROW)) {
     // This is an estimate, see nsDisplayNotation::Paint for the exact head size
     nscoord arrowHeadSize = kArrowHeadSize * mRuleThickness;
     // We want that the arrow shaft strikes the menclose content and that the
     // arrow head does not overlap with that content. Hence we add some space
     // on the right. We don't add space on the top but only ensure that the
     // ascent is large enough.
     dx_right = std::max(dx_right, arrowHeadSize);
     mBoundingMetrics.ascent = std::max(mBoundingMetrics.ascent, arrowHeadSize);
   }
   ///////////////
   // circle notation: we don't want the ellipse to overlap the enclosed
   // content. Hence, we need to increase the size of the bounding box by a
   // factor of at least sqrt(2).
   if (IsToDraw(NOTATION_CIRCLE)) {
     double ratio = (sqrt(2.0) - 1.0) / 2.0;
     nscoord padding2;
     // Update horizontal parameters
     padding2 = ratio * bmBase.width;
     dx_left = std::max(dx_left, padding2);
     dx_right = std::max(dx_right, padding2);
     // Update vertical parameters
     padding2 = ratio * (bmBase.ascent + bmBase.descent);
     mBoundingMetrics.ascent = std::max(mBoundingMetrics.ascent,
                                      bmBase.ascent + padding2);
     mBoundingMetrics.descent = std::max(mBoundingMetrics.descent,
                                       bmBase.descent + padding2);
   }
   ///////////////
   // longdiv notation:
   if (IsToDraw(NOTATION_LONGDIV)) {
     if (aWidthOnly) {
         nscoord longdiv_width = mMathMLChar[mLongDivCharIndex].
           GetMaxWidth(PresContext(), aRenderingContext);
         // Update horizontal parameters
         dx_left = std::max(dx_left, longdiv_width);
     } else {
       // Stretch the parenthesis to the appropriate height if it is not
       // big enough.
       nsBoundingMetrics contSize = bmBase;
       contSize.ascent = mRuleThickness;
       contSize.descent = bmBase.ascent + bmBase.descent + psi;
       // height(longdiv) should be >= height(base) + psi + mRuleThickness
       mMathMLChar[mLongDivCharIndex].Stretch(PresContext(), aRenderingContext,
                                              NS_STRETCH_DIRECTION_VERTICAL,
                                              contSize, bmLongdivChar,
                                              NS_STRETCH_LARGER, false);
       mMathMLChar[mLongDivCharIndex].GetBoundingMetrics(bmLongdivChar);
       // Update horizontal parameters
       dx_left = std::max(dx_left, bmLongdivChar.width);
       // Update vertical parameters
       longdivAscent = bmBase.ascent + psi + mRuleThickness;
       longdivDescent = std::max(bmBase.descent,
                               (bmLongdivChar.ascent + bmLongdivChar.descent -
                                longdivAscent));
       mBoundingMetrics.ascent = std::max(mBoundingMetrics.ascent,
                                        longdivAscent);
       mBoundingMetrics.descent = std::max(mBoundingMetrics.descent,
                                         longdivDescent);
     }
   }
   ///////////////
   // radical notation:
   if (IsToDraw(NOTATION_RADICAL)) {
     nscoord *dx_leading = StyleVisibility()->mDirection ? &dx_right : &dx_left;
     if (aWidthOnly) {
       nscoord radical_width = mMathMLChar[mRadicalCharIndex].
         GetMaxWidth(PresContext(), aRenderingContext);
       // Update horizontal parameters
       *dx_leading = std::max(*dx_leading, radical_width);
     } else {
       // Stretch the radical symbol to the appropriate height if it is not
       // big enough.
       nsBoundingMetrics contSize = bmBase;
       contSize.ascent = mRuleThickness;
       contSize.descent = bmBase.ascent + bmBase.descent + psi;
       // height(radical) should be >= height(base) + psi + mRuleThickness
       mMathMLChar[mRadicalCharIndex].Stretch(PresContext(), aRenderingContext,
                                              NS_STRETCH_DIRECTION_VERTICAL,
                                              contSize, bmRadicalChar,
                                              NS_STRETCH_LARGER,
                                              StyleVisibility()->mDirection);
       mMathMLChar[mRadicalCharIndex].GetBoundingMetrics(bmRadicalChar);
       // Update horizontal parameters
       *dx_leading = std::max(*dx_leading, bmRadicalChar.width);
       // Update vertical parameters
       radicalAscent = bmBase.ascent + psi + mRuleThickness;
       radicalDescent = std::max(bmBase.descent,
                               (bmRadicalChar.ascent + bmRadicalChar.descent -
                                radicalAscent));
       mBoundingMetrics.ascent = std::max(mBoundingMetrics.ascent,
                                        radicalAscent);
       mBoundingMetrics.descent = std::max(mBoundingMetrics.descent,
                                         radicalDescent);
     }
   }
   ///////////////
   //
   if (IsToDraw(NOTATION_CIRCLE) ||
       IsToDraw(NOTATION_ROUNDEDBOX) ||
       (IsToDraw(NOTATION_LEFT) && IsToDraw(NOTATION_RIGHT))) {
     // center the menclose around the content (horizontally)
     dx_left = dx_right = std::max(dx_left, dx_right);
   }
   ///////////////
   // The maximum size is now computed: set the remaining parameters
   mBoundingMetrics.width = dx_left + bmBase.width + dx_right;
   mBoundingMetrics.leftBearing = std::min(0, dx_left + bmBase.leftBearing);
   mBoundingMetrics.rightBearing =
     std::max(mBoundingMetrics.width, dx_left + bmBase.rightBearing);
   aDesiredSize.Width() = mBoundingMetrics.width;
   aDesiredSize.SetTopAscent(std::max(mBoundingMetrics.ascent, baseSize.TopAscent()));
   aDesiredSize.Height() = aDesiredSize.TopAscent() +
     std::max(mBoundingMetrics.descent, baseSize.Height() - baseSize.TopAscent());
   if (IsToDraw(NOTATION_LONGDIV) || IsToDraw(NOTATION_RADICAL)) {
     // get the leading to be left at the top of the resulting frame
     // this seems more reliable than using fm->GetLeading() on suspicious
     // fonts
     nscoord leading = nscoord(0.2f * mEmHeight);
     nscoord desiredSizeAscent = aDesiredSize.TopAscent();
     nscoord desiredSizeDescent = aDesiredSize.Height() - aDesiredSize.TopAscent();
     if (IsToDraw(NOTATION_LONGDIV)) {
       desiredSizeAscent = std::max(desiredSizeAscent,
                                  longdivAscent + leading);
       desiredSizeDescent = std::max(desiredSizeDescent,
                                   longdivDescent + mRuleThickness);
     }
     if (IsToDraw(NOTATION_RADICAL)) {
       desiredSizeAscent = std::max(desiredSizeAscent,
                                  radicalAscent + leading);
       desiredSizeDescent = std::max(desiredSizeDescent,
                                   radicalDescent + mRuleThickness);
     }
     aDesiredSize.SetTopAscent(desiredSizeAscent);
     aDesiredSize.Height() = desiredSizeAscent + desiredSizeDescent;
   }
   if (IsToDraw(NOTATION_CIRCLE) ||
       IsToDraw(NOTATION_ROUNDEDBOX) ||
       (IsToDraw(NOTATION_TOP) && IsToDraw(NOTATION_BOTTOM))) {
     // center the menclose around the content (vertically)
     nscoord dy = std::max(aDesiredSize.TopAscent() - bmBase.ascent,
                         aDesiredSize.Height() - aDesiredSize.TopAscent() -
                         bmBase.descent);
     aDesiredSize.SetTopAscent(bmBase.ascent + dy);
     aDesiredSize.Height() = aDesiredSize.TopAscent() + bmBase.descent + dy;
   }
   // Update mBoundingMetrics ascent/descent
   if (IsToDraw(NOTATION_TOP) ||
       IsToDraw(NOTATION_RIGHT) ||
       IsToDraw(NOTATION_LEFT) ||
       IsToDraw(NOTATION_UPDIAGONALSTRIKE) ||
       IsToDraw(NOTATION_UPDIAGONALARROW) ||
       IsToDraw(NOTATION_DOWNDIAGONALSTRIKE) ||
       IsToDraw(NOTATION_VERTICALSTRIKE) ||
       IsToDraw(NOTATION_CIRCLE) ||
       IsToDraw(NOTATION_ROUNDEDBOX))
     mBoundingMetrics.ascent = aDesiredSize.TopAscent();
   if (IsToDraw(NOTATION_BOTTOM) ||
       IsToDraw(NOTATION_RIGHT) ||
       IsToDraw(NOTATION_LEFT) ||
       IsToDraw(NOTATION_UPDIAGONALSTRIKE) ||
       IsToDraw(NOTATION_UPDIAGONALARROW) ||
       IsToDraw(NOTATION_DOWNDIAGONALSTRIKE) ||
       IsToDraw(NOTATION_VERTICALSTRIKE) ||
       IsToDraw(NOTATION_CIRCLE) ||
       IsToDraw(NOTATION_ROUNDEDBOX))
     mBoundingMetrics.descent = aDesiredSize.Height() - aDesiredSize.TopAscent();
   aDesiredSize.mBoundingMetrics = mBoundingMetrics;
   mReference.x = 0;
   mReference.y = aDesiredSize.TopAscent();
   if (aPlaceOrigin) {
     //////////////////
     // Set position and size of MathMLChars
     if (IsToDraw(NOTATION_LONGDIV))
       mMathMLChar[mLongDivCharIndex].SetRect(nsRect(dx_left -
                                                     bmLongdivChar.width,
                                                     aDesiredSize.TopAscent() -
                                                     longdivAscent,
                                                     bmLongdivChar.width,
                                                     bmLongdivChar.ascent +
                                                     bmLongdivChar.descent));
     if (IsToDraw(NOTATION_RADICAL)) {
       nscoord dx = (StyleVisibility()->mDirection ?
                     dx_left + bmBase.width : dx_left - bmRadicalChar.width);
       mMathMLChar[mRadicalCharIndex].SetRect(nsRect(dx,
                                                     aDesiredSize.TopAscent() -
                                                     radicalAscent,
                                                     bmRadicalChar.width,
                                                     bmRadicalChar.ascent +
                                                     bmRadicalChar.descent));
     }
     mContentWidth = bmBase.width;
     //////////////////
     // Finish reflowing child frames
     PositionRowChildFrames(dx_left, aDesiredSize.TopAscent());
   }
   return NS_OK;
 }
 nscoord
 nsMathMLmencloseFrame::FixInterFrameSpacing(nsHTMLReflowMetrics& aDesiredSize)
 {
   nscoord gap = nsMathMLContainerFrame::FixInterFrameSpacing(aDesiredSize);
   if (!gap)
     return 0;
   // Move the MathML characters
   nsRect rect;
   for (uint32_t i = 0; i < mMathMLChar.Length(); i++) {
     mMathMLChar[i].GetRect(rect);
     rect.MoveBy(gap, 0);
     mMathMLChar[i].SetRect(rect);
   }
   return gap;
 }
 nsresult
 nsMathMLmencloseFrame::AttributeChanged(int32_t         aNameSpaceID,
                                         nsIAtom*        aAttribute,
                                         int32_t         aModType)
 {
   if (aAttribute == nsGkAtoms::notation_) {
     InitNotations();
   }
   return nsMathMLContainerFrame::
     AttributeChanged(aNameSpaceID, aAttribute, aModType);
 }
 //////////////////
 // the Style System will use these to pass the proper style context to our
 // MathMLChar
 nsStyleContext*
 nsMathMLmencloseFrame::GetAdditionalStyleContext(int32_t aIndex) const
 {
   int32_t len = mMathMLChar.Length();
   if (aIndex >= 0 && aIndex < len)
     return mMathMLChar[aIndex].GetStyleContext();
   else
     return nullptr;
 }
 void
 nsMathMLmencloseFrame::SetAdditionalStyleContext(int32_t          aIndex,
                                                  nsStyleContext*  aStyleContext)
 {
   int32_t len = mMathMLChar.Length();
   if (aIndex >= 0 && aIndex < len)
     mMathMLChar[aIndex].SetStyleContext(aStyleContext);
 }
 class nsDisplayNotation : public nsDisplayItem
 {
 public:
   nsDisplayNotation(nsDisplayListBuilder* aBuilder,
                     nsIFrame* aFrame, const nsRect& aRect,
                     nscoord aThickness, nsMencloseNotation aType)
     : nsDisplayItem(aBuilder, aFrame), mRect(aRect),
       mThickness(aThickness), mType(aType) {
     MOZ_COUNT_CTOR(nsDisplayNotation);
   }
 #ifdef NS_BUILD_REFCNT_LOGGING
   virtual ~nsDisplayNotation() {
     MOZ_COUNT_DTOR(nsDisplayNotation);
   }
 #endif
   virtual void Paint(nsDisplayListBuilder* aBuilder,
                      nsRenderingContext* aCtx) MOZ_OVERRIDE;
   NS_DISPLAY_DECL_NAME("MathMLMencloseNotation", TYPE_MATHML_MENCLOSE_NOTATION)
 private:
   nsRect             mRect;
   nscoord            mThickness;
   nsMencloseNotation mType;
 };
 void nsDisplayNotation::Paint(nsDisplayListBuilder* aBuilder,
                               nsRenderingContext* aCtx)
 {
   // get the gfxRect
   nsPresContext* presContext = mFrame->PresContext();
   gfxRect rect = presContext->AppUnitsToGfxUnits(mRect + ToReferenceFrame());
   // paint the frame with the current text color
   aCtx->SetColor(mFrame->GetVisitedDependentColor(eCSSProperty_color));
   // change line width to mThickness
   gfxContext *gfxCtx = aCtx->ThebesContext();
   gfxFloat e = presContext->AppUnitsToGfxUnits(mThickness);
   gfxCtx->Save();
   gfxCtx->SetLineWidth(e);
   rect.Deflate(e / 2.0);
   switch(mType)
     {
     case NOTATION_CIRCLE:
       gfxCtx->NewPath();
       gfxCtx->Ellipse(rect.Center(), rect.Size());
       gfxCtx->Stroke();
       break;
     case NOTATION_ROUNDEDBOX:
       gfxCtx->NewPath();
       gfxCtx->RoundedRectangle(rect, gfxCornerSizes(3 * e), true);
       gfxCtx->Stroke();
       break;
     case NOTATION_UPDIAGONALSTRIKE:
       gfxCtx->NewPath();
       gfxCtx->Line(rect.BottomLeft(), rect.TopRight());
       gfxCtx->Stroke();
       break;
     case NOTATION_DOWNDIAGONALSTRIKE:
       gfxCtx->NewPath();
       gfxCtx->Line(rect.TopLeft(), rect.BottomRight());
       gfxCtx->Stroke();
       break;
     case NOTATION_UPDIAGONALARROW: {
       // Compute some parameters to draw the updiagonalarrow. The values below
       // are taken from MathJax's HTML-CSS output.
       gfxFloat W = rect.Width(); gfxFloat H = rect.Height();
       gfxFloat l = sqrt(W*W + H*H);
       gfxFloat f = gfxFloat(kArrowHeadSize) * e / l;
       gfxFloat w = W * f; gfxFloat h = H * f;
       // Draw the arrow shaft
       gfxCtx->NewPath();
       gfxCtx->Line(rect.BottomLeft(), rect.TopRight() + gfxPoint(-.7*w, .7*h));
       gfxCtx->Stroke();
       // Draw the arrow head
       gfxCtx->NewPath();
       gfxPoint p[] = {
         rect.TopRight(),
         rect.TopRight() + gfxPoint(-w -.4*h, std::max(-e / 2.0, h - .4*w)),
         rect.TopRight() + gfxPoint(-.7*w, .7*h),
         rect.TopRight() + gfxPoint(std::min(e / 2.0, -w + .4*h), h + .4*w),
         rect.TopRight()
       };
       gfxCtx->Polygon(p, MOZ_ARRAY_LENGTH(p));
       gfxCtx->Fill();
     }
       break;
     default:
       NS_NOTREACHED("This notation can not be drawn using nsDisplayNotation");
       break;
     }
   gfxCtx->Restore();
 }
 void
 nsMathMLmencloseFrame::DisplayNotation(nsDisplayListBuilder* aBuilder,
                                        nsIFrame* aFrame, const nsRect& aRect,
                                        const nsDisplayListSet& aLists,
                                        nscoord aThickness,
                                        nsMencloseNotation aType)
 {
   if (!aFrame->StyleVisibility()->IsVisible() || aRect.IsEmpty() ||
       aThickness <= 0)
     return;
   aLists.Content()->AppendNewToTop(new (aBuilder)
     nsDisplayNotation(aBuilder, aFrame, aRect, aThickness, aType));
 }

The Tor Browser / annotate

layout/mathml/nsMathMLmencloseFrame.cpp@b8a032363ba2 (annotated)

layout/mathml/nsMathMLmencloseFrame.cpp