/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */ /* vim: set ts=8 sts=2 et sw=2 tw=80: */ /* 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 "nsMathMLmmultiscriptsFrame.h" #include "mozilla/dom/Document.h" #include "mozilla/dom/Element.h" #include "mozilla/PresShell.h" #include "mozilla/StaticPrefs_mathml.h" #include "nsLayoutUtils.h" #include "nsPresContext.h" #include #include "gfxContext.h" #include "gfxMathTable.h" #include "gfxTextRun.h" using namespace mozilla; // // -- attach prescripts and tensor indices to a base - // implementation -- attach a subscript to a base - implementation // -- attach a subscript-superscript pair to a base - implementation // -- attach a superscript to a base - implementation // nsIFrame* NS_NewMathMLmmultiscriptsFrame(PresShell* aPresShell, ComputedStyle* aStyle) { return new (aPresShell) nsMathMLmmultiscriptsFrame(aStyle, aPresShell->GetPresContext()); } NS_IMPL_FRAMEARENA_HELPERS(nsMathMLmmultiscriptsFrame) nsMathMLmmultiscriptsFrame::~nsMathMLmmultiscriptsFrame() = default; uint8_t nsMathMLmmultiscriptsFrame::ScriptIncrement(nsIFrame* aFrame) { if (!aFrame) return 0; if (mFrames.ContainsFrame(aFrame)) { if (mFrames.FirstChild() == aFrame || aFrame->GetContent()->IsMathMLElement(nsGkAtoms::mprescripts_)) { return 0; // No script increment for base frames or prescript markers } return 1; } return 0; // not a child } NS_IMETHODIMP nsMathMLmmultiscriptsFrame::TransmitAutomaticData() { // if our base is an embellished operator, let its state bubble to us mPresentationData.baseFrame = mFrames.FirstChild(); GetEmbellishDataFrom(mPresentationData.baseFrame, mEmbellishData); // The TeXbook (Ch 17. p.141) says the superscript inherits the compression // while the subscript is compressed. So here we collect subscripts and set // the compression flag in them. int32_t count = 0; bool isSubScript = !mContent->IsMathMLElement(nsGkAtoms::msup_); AutoTArray subScriptFrames; nsIFrame* childFrame = mFrames.FirstChild(); while (childFrame) { if (childFrame->GetContent()->IsMathMLElement(nsGkAtoms::mprescripts_)) { // mprescripts frame } else if (0 == count) { // base frame } else { // super/subscript block if (isSubScript) { // subscript subScriptFrames.AppendElement(childFrame); } else { // superscript } PropagateFrameFlagFor(childFrame, NS_FRAME_MATHML_SCRIPT_DESCENDANT); isSubScript = !isSubScript; } count++; childFrame = childFrame->GetNextSibling(); } for (int32_t i = subScriptFrames.Length() - 1; i >= 0; i--) { childFrame = subScriptFrames[i]; PropagatePresentationDataFor(childFrame, NS_MATHML_COMPRESSED, NS_MATHML_COMPRESSED); } return NS_OK; } /* virtual */ nsresult nsMathMLmmultiscriptsFrame::Place(DrawTarget* aDrawTarget, bool aPlaceOrigin, ReflowOutput& aDesiredSize) { nscoord subScriptShift = 0; nscoord supScriptShift = 0; float fontSizeInflation = nsLayoutUtils::FontSizeInflationFor(this); return PlaceMultiScript(PresContext(), aDrawTarget, aPlaceOrigin, aDesiredSize, this, subScriptShift, supScriptShift, fontSizeInflation); } // exported routine that both munderover and mmultiscripts share. // munderover uses this when movablelimits is set. nsresult nsMathMLmmultiscriptsFrame::PlaceMultiScript( nsPresContext* aPresContext, DrawTarget* aDrawTarget, bool aPlaceOrigin, ReflowOutput& aDesiredSize, nsMathMLContainerFrame* aFrame, nscoord aUserSubScriptShift, nscoord aUserSupScriptShift, float aFontSizeInflation) { nsAtom* tag = aFrame->GetContent()->NodeInfo()->NameAtom(); // This function deals with both munderover etc. as well as msubsup etc. // As the former behaves identically to the later, we treat it as such // to avoid additional checks later. if (aFrame->GetContent()->IsMathMLElement(nsGkAtoms::mover_)) tag = nsGkAtoms::msup_; else if (aFrame->GetContent()->IsMathMLElement(nsGkAtoms::munder_)) tag = nsGkAtoms::msub_; else if (aFrame->GetContent()->IsMathMLElement(nsGkAtoms::munderover_)) tag = nsGkAtoms::msubsup_; nsBoundingMetrics bmFrame; nscoord minShiftFromXHeight, subDrop, supDrop; //////////////////////////////////////// // Initialize super/sub shifts that // depend only on the current font //////////////////////////////////////// nsIFrame* baseFrame = aFrame->PrincipalChildList().FirstChild(); if (!baseFrame) { if (tag == nsGkAtoms::mmultiscripts_) aFrame->ReportErrorToConsole("NoBase"); else aFrame->ReportChildCountError(); return aFrame->PlaceAsMrow(aDrawTarget, aPlaceOrigin, aDesiredSize); } // get x-height (an ex) const nsStyleFont* font = aFrame->StyleFont(); RefPtr fm = nsLayoutUtils::GetFontMetricsForFrame(baseFrame, aFontSizeInflation); nscoord xHeight = fm->XHeight(); nscoord oneDevPixel = fm->AppUnitsPerDevPixel(); RefPtr mathFont = fm->GetThebesFontGroup()->GetFirstMathFont(); // scriptspace from TeX for extra spacing after sup/subscript nscoord scriptSpace; if (mathFont) { scriptSpace = mathFont->MathTable()->Constant( gfxMathTable::SpaceAfterScript, oneDevPixel); } else { // (0.5pt in plain TeX) scriptSpace = nsPresContext::CSSPointsToAppUnits(0.5f); } // Try and read sub and sup drops from the MATH table. if (mathFont) { subDrop = mathFont->MathTable()->Constant( gfxMathTable::SubscriptBaselineDropMin, oneDevPixel); supDrop = mathFont->MathTable()->Constant( gfxMathTable::SuperscriptBaselineDropMax, oneDevPixel); } // force the scriptSpace to be at least 1 pixel nscoord onePixel = nsPresContext::CSSPixelsToAppUnits(1); scriptSpace = std::max(onePixel, scriptSpace); ///////////////////////////////////// // first the shift for the subscript nscoord subScriptShift; if (mathFont) { // Try and get the sub script shift from the MATH table. Note that contrary // to TeX we only have one parameter. subScriptShift = mathFont->MathTable()->Constant( gfxMathTable::SubscriptShiftDown, oneDevPixel); } else { // subScriptShift{1,2} // = minimum amount to shift the subscript down // = sub{1,2} in TeXbook // subScriptShift1 = subscriptshift attribute * x-height nscoord subScriptShift1, subScriptShift2; // Get subScriptShift{1,2} default from font GetSubScriptShifts(fm, subScriptShift1, subScriptShift2); if (tag == nsGkAtoms::msub_) { subScriptShift = subScriptShift1; } else { subScriptShift = std::max(subScriptShift1, subScriptShift2); } } if (0 < aUserSubScriptShift) { // the user has set the subscriptshift attribute subScriptShift = std::max(subScriptShift, aUserSubScriptShift); } ///////////////////////////////////// // next the shift for the superscript nscoord supScriptShift; nsPresentationData presentationData; aFrame->GetPresentationData(presentationData); if (mathFont) { // Try and get the super script shift from the MATH table. Note that // contrary to TeX we only have two parameters. supScriptShift = mathFont->MathTable()->Constant( NS_MATHML_IS_COMPRESSED(presentationData.flags) ? gfxMathTable::SuperscriptShiftUpCramped : gfxMathTable::SuperscriptShiftUp, oneDevPixel); } else { // 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); // get sup script shift depending on current script level and display style // Rule 18c, App. G, TeXbook if (font->mMathDepth == 0 && font->mMathStyle == StyleMathStyle::Normal && !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; } } if (0 < aUserSupScriptShift) { // the user has set the supscriptshift attribute supScriptShift = std::max(supScriptShift, aUserSupScriptShift); } //////////////////////////////////// // Get the children's sizes //////////////////////////////////// const WritingMode wm(aDesiredSize.GetWritingMode()); nscoord width = 0, prescriptsWidth = 0, rightBearing = 0; nscoord minSubScriptShift = 0, minSupScriptShift = 0; nscoord trySubScriptShift = subScriptShift; nscoord trySupScriptShift = supScriptShift; nscoord maxSubScriptShift = subScriptShift; nscoord maxSupScriptShift = supScriptShift; ReflowOutput baseSize(wm); ReflowOutput subScriptSize(wm); ReflowOutput supScriptSize(wm); ReflowOutput multiSubSize(wm), multiSupSize(wm); baseFrame = nullptr; nsIFrame* subScriptFrame = nullptr; nsIFrame* supScriptFrame = nullptr; nsIFrame* prescriptsFrame = nullptr; // frame of , if there. bool firstPrescriptsPair = false; nsBoundingMetrics bmBase, bmSubScript, bmSupScript, bmMultiSub, bmMultiSup; multiSubSize.SetBlockStartAscent(-0x7FFFFFFF); multiSupSize.SetBlockStartAscent(-0x7FFFFFFF); bmMultiSub.ascent = bmMultiSup.ascent = -0x7FFFFFFF; bmMultiSub.descent = bmMultiSup.descent = -0x7FFFFFFF; nscoord italicCorrection = 0; nsBoundingMetrics boundingMetrics; boundingMetrics.width = 0; boundingMetrics.ascent = boundingMetrics.descent = -0x7FFFFFFF; aDesiredSize.Width() = aDesiredSize.Height() = 0; int32_t count = 0; // Boolean to determine whether the current child is a subscript. // Note that only msup starts with a superscript. bool isSubScript = (tag != nsGkAtoms::msup_); nsIFrame* childFrame = aFrame->PrincipalChildList().FirstChild(); while (childFrame) { if (childFrame->GetContent()->IsMathMLElement(nsGkAtoms::mprescripts_)) { if (tag != nsGkAtoms::mmultiscripts_) { if (aPlaceOrigin) { aFrame->ReportInvalidChildError(nsGkAtoms::mprescripts_); } return aFrame->PlaceAsMrow(aDrawTarget, aPlaceOrigin, aDesiredSize); } if (prescriptsFrame) { // duplicate found // report an error, encourage people to get their markups in order if (aPlaceOrigin) { aFrame->ReportErrorToConsole("DuplicateMprescripts"); } return aFrame->PlaceAsMrow(aDrawTarget, aPlaceOrigin, aDesiredSize); } if (!isSubScript) { if (aPlaceOrigin) { aFrame->ReportErrorToConsole("SubSupMismatch"); } return aFrame->PlaceAsMrow(aDrawTarget, aPlaceOrigin, aDesiredSize); } prescriptsFrame = childFrame; firstPrescriptsPair = true; } else if (0 == count) { // base baseFrame = childFrame; GetReflowAndBoundingMetricsFor(baseFrame, baseSize, bmBase); if (tag != nsGkAtoms::msub_) { // Apply italics correction if there is the potential for a // postsupscript. GetItalicCorrection(bmBase, italicCorrection); // If italics correction is applied, we always add "a little to spare" // (see TeXbook Ch.11, p.64), as we estimate the italic creation // ourselves and it isn't the same as TeX. italicCorrection += onePixel; } // we update boundingMetrics.{ascent,descent} with that // of the baseFrame only after processing all the sup/sub pairs boundingMetrics.width = bmBase.width; boundingMetrics.rightBearing = bmBase.rightBearing; boundingMetrics.leftBearing = bmBase.leftBearing; // until overwritten } else { // super/subscript block if (isSubScript) { // subscript subScriptFrame = childFrame; GetReflowAndBoundingMetricsFor(subScriptFrame, subScriptSize, bmSubScript); if (!mathFont) { // get the subdrop from the subscript font GetSubDropFromChild(subScriptFrame, subDrop, aFontSizeInflation); } // parameter v, Rule 18a, App. G, TeXbook minSubScriptShift = bmBase.descent + subDrop; trySubScriptShift = std::max(minSubScriptShift, subScriptShift); multiSubSize.SetBlockStartAscent(std::max( multiSubSize.BlockStartAscent(), subScriptSize.BlockStartAscent())); bmMultiSub.ascent = std::max(bmMultiSub.ascent, bmSubScript.ascent); bmMultiSub.descent = std::max(bmMultiSub.descent, bmSubScript.descent); multiSubSize.Height() = std::max(multiSubSize.Height(), subScriptSize.Height() - subScriptSize.BlockStartAscent()); if (bmSubScript.width) width = bmSubScript.width + scriptSpace; rightBearing = bmSubScript.rightBearing; if (tag == nsGkAtoms::msub_) { boundingMetrics.rightBearing = boundingMetrics.width + rightBearing; boundingMetrics.width += width; nscoord subscriptTopMax; if (mathFont) { subscriptTopMax = mathFont->MathTable()->Constant( gfxMathTable::SubscriptTopMax, oneDevPixel); } else { // get min subscript shift limit from x-height // = h(x) - 4/5 * sigma_5, Rule 18b, App. G, TeXbook subscriptTopMax = NSToCoordRound((4.0f / 5.0f) * xHeight); } nscoord minShiftFromXHeight = bmSubScript.ascent - subscriptTopMax; maxSubScriptShift = std::max(trySubScriptShift, minShiftFromXHeight); maxSubScriptShift = std::max(maxSubScriptShift, trySubScriptShift); trySubScriptShift = subScriptShift; } } else { // supscript supScriptFrame = childFrame; GetReflowAndBoundingMetricsFor(supScriptFrame, supScriptSize, bmSupScript); if (!mathFont) { // get the supdrop from the supscript font GetSupDropFromChild(supScriptFrame, supDrop, aFontSizeInflation); } // parameter u, Rule 18a, App. G, TeXbook minSupScriptShift = bmBase.ascent - supDrop; nscoord superscriptBottomMin; if (mathFont) { superscriptBottomMin = mathFont->MathTable()->Constant( gfxMathTable::SuperscriptBottomMin, oneDevPixel); } else { // get min supscript shift limit from x-height // = d(x) + 1/4 * sigma_5, Rule 18c, App. G, TeXbook superscriptBottomMin = NSToCoordRound((1.0f / 4.0f) * xHeight); } minShiftFromXHeight = bmSupScript.descent + superscriptBottomMin; trySupScriptShift = std::max( minSupScriptShift, std::max(minShiftFromXHeight, supScriptShift)); multiSupSize.SetBlockStartAscent(std::max( multiSupSize.BlockStartAscent(), supScriptSize.BlockStartAscent())); bmMultiSup.ascent = std::max(bmMultiSup.ascent, bmSupScript.ascent); bmMultiSup.descent = std::max(bmMultiSup.descent, bmSupScript.descent); multiSupSize.Height() = std::max(multiSupSize.Height(), supScriptSize.Height() - supScriptSize.BlockStartAscent()); if (bmSupScript.width) width = std::max(width, bmSupScript.width + scriptSpace); if (!prescriptsFrame) { // we are still looping over base & postscripts rightBearing = std::max(rightBearing, italicCorrection + bmSupScript.rightBearing); boundingMetrics.rightBearing = boundingMetrics.width + rightBearing; boundingMetrics.width += width; } else { prescriptsWidth += width; if (firstPrescriptsPair) { firstPrescriptsPair = false; boundingMetrics.leftBearing = std::min(bmSubScript.leftBearing, bmSupScript.leftBearing); } } width = rightBearing = 0; // negotiate between the various shifts so that // there is enough gap between the sup and subscripts // Rule 18e, App. G, TeXbook if (tag == nsGkAtoms::mmultiscripts_ || tag == nsGkAtoms::msubsup_) { nscoord subSuperscriptGapMin; if (mathFont) { subSuperscriptGapMin = mathFont->MathTable()->Constant( gfxMathTable::SubSuperscriptGapMin, oneDevPixel); } else { nscoord ruleSize; GetRuleThickness(aDrawTarget, fm, ruleSize); subSuperscriptGapMin = 4 * ruleSize; } nscoord gap = (trySupScriptShift - bmSupScript.descent) - (bmSubScript.ascent - trySubScriptShift); if (gap < subSuperscriptGapMin) { // adjust trySubScriptShift to get a gap of subSuperscriptGapMin trySubScriptShift += subSuperscriptGapMin - gap; } // next we want to ensure that the bottom of the superscript // will be > superscriptBottomMaxWithSubscript nscoord superscriptBottomMaxWithSubscript; if (mathFont) { superscriptBottomMaxWithSubscript = mathFont->MathTable()->Constant( gfxMathTable::SuperscriptBottomMaxWithSubscript, oneDevPixel); } else { superscriptBottomMaxWithSubscript = NSToCoordRound((4.0f / 5.0f) * xHeight); } gap = superscriptBottomMaxWithSubscript - (trySupScriptShift - bmSupScript.descent); if (gap > 0) { trySupScriptShift += gap; trySubScriptShift -= gap; } } maxSubScriptShift = std::max(maxSubScriptShift, trySubScriptShift); maxSupScriptShift = std::max(maxSupScriptShift, trySupScriptShift); trySubScriptShift = subScriptShift; trySupScriptShift = supScriptShift; } isSubScript = !isSubScript; } count++; childFrame = childFrame->GetNextSibling(); } // NoBase error may also have been reported above if ((count != 2 && (tag == nsGkAtoms::msup_ || tag == nsGkAtoms::msub_)) || (count != 3 && tag == nsGkAtoms::msubsup_) || !baseFrame || (!isSubScript && tag == nsGkAtoms::mmultiscripts_)) { // report an error, encourage people to get their markups in order if (aPlaceOrigin) { if ((count != 2 && (tag == nsGkAtoms::msup_ || tag == nsGkAtoms::msub_)) || (count != 3 && tag == nsGkAtoms::msubsup_)) { aFrame->ReportChildCountError(); } else if (!baseFrame) { aFrame->ReportErrorToConsole("NoBase"); } else { aFrame->ReportErrorToConsole("SubSupMismatch"); } } return aFrame->PlaceAsMrow(aDrawTarget, aPlaceOrigin, aDesiredSize); } // we left out the width of prescripts, so ... boundingMetrics.rightBearing += prescriptsWidth; boundingMetrics.width += prescriptsWidth; // Zero out the shifts in where a frame isn't present to avoid the potential // for overflow. if (!subScriptFrame) maxSubScriptShift = 0; if (!supScriptFrame) maxSupScriptShift = 0; // we left out the base during our bounding box updates, so ... if (tag == nsGkAtoms::msub_) { boundingMetrics.ascent = std::max(bmBase.ascent, bmMultiSub.ascent - maxSubScriptShift); } else { boundingMetrics.ascent = std::max(bmBase.ascent, (bmMultiSup.ascent + maxSupScriptShift)); } if (tag == nsGkAtoms::msup_) { boundingMetrics.descent = std::max(bmBase.descent, bmMultiSup.descent - maxSupScriptShift); } else { boundingMetrics.descent = std::max(bmBase.descent, (bmMultiSub.descent + maxSubScriptShift)); } aFrame->SetBoundingMetrics(boundingMetrics); // get the reflow metrics ... aDesiredSize.SetBlockStartAscent( std::max(baseSize.BlockStartAscent(), std::max(multiSubSize.BlockStartAscent() - maxSubScriptShift, multiSupSize.BlockStartAscent() + maxSupScriptShift))); aDesiredSize.Height() = aDesiredSize.BlockStartAscent() + std::max(baseSize.Height() - baseSize.BlockStartAscent(), std::max(multiSubSize.Height() + maxSubScriptShift, multiSupSize.Height() - maxSupScriptShift)); aDesiredSize.Width() = boundingMetrics.width; aDesiredSize.mBoundingMetrics = boundingMetrics; aFrame->SetReference(nsPoint(0, aDesiredSize.BlockStartAscent())); ////////////////// // Place Children // Place prescripts, followed by base, and then postscripts. // The list of frames is in the order: {base} {postscripts} {prescripts} // We go over the list in a circular manner, starting at if (aPlaceOrigin) { nscoord dx = 0, dy = 0; // With msub and msup there is only one element and // subscriptFrame/supScriptFrame have already been set above where // relevant. In these cases we skip to the reflow part. if (tag == nsGkAtoms::msub_ || tag == nsGkAtoms::msup_) count = 1; else count = 0; childFrame = prescriptsFrame; bool isPreScript = true; do { if (!childFrame) { // end of prescripts, isPreScript = false; // place the base ... childFrame = baseFrame; dy = aDesiredSize.BlockStartAscent() - baseSize.BlockStartAscent(); FinishReflowChild( baseFrame, aPresContext, baseSize, nullptr, aFrame->MirrorIfRTL(aDesiredSize.Width(), baseSize.Width(), dx), dy, ReflowChildFlags::Default); dx += bmBase.width; } else if (prescriptsFrame == childFrame) { // Clear reflow flags of prescripts frame. prescriptsFrame->DidReflow(aPresContext, nullptr); } else { // process each sup/sub pair if (0 == count) { subScriptFrame = childFrame; count = 1; } else if (1 == count) { if (tag != nsGkAtoms::msub_) supScriptFrame = childFrame; count = 0; // get the ascent/descent of sup/subscripts stored in their rects // rect.x = descent, rect.y = ascent if (subScriptFrame) GetReflowAndBoundingMetricsFor(subScriptFrame, subScriptSize, bmSubScript); if (supScriptFrame) GetReflowAndBoundingMetricsFor(supScriptFrame, supScriptSize, bmSupScript); width = std::max(subScriptSize.Width(), supScriptSize.Width()); if (subScriptFrame) { nscoord x = dx; // prescripts should be right aligned // https://bugzilla.mozilla.org/show_bug.cgi?id=928675 if (isPreScript) x += width - subScriptSize.Width(); dy = aDesiredSize.BlockStartAscent() - subScriptSize.BlockStartAscent() + maxSubScriptShift; FinishReflowChild(subScriptFrame, aPresContext, subScriptSize, nullptr, aFrame->MirrorIfRTL(aDesiredSize.Width(), subScriptSize.Width(), x), dy, ReflowChildFlags::Default); } if (supScriptFrame) { nscoord x = dx; if (isPreScript) { x += width - supScriptSize.Width(); } else { // post superscripts are shifted by the italic correction value x += italicCorrection; } dy = aDesiredSize.BlockStartAscent() - supScriptSize.BlockStartAscent() - maxSupScriptShift; FinishReflowChild(supScriptFrame, aPresContext, supScriptSize, nullptr, aFrame->MirrorIfRTL(aDesiredSize.Width(), supScriptSize.Width(), x), dy, ReflowChildFlags::Default); } dx += width + scriptSpace; } } childFrame = childFrame->GetNextSibling(); } while (prescriptsFrame != childFrame); } return NS_OK; }