/* -*- 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 "nsMathMLmmultiscriptsFrame.h" #include "nsPresContext.h" #include "nsRenderingContext.h" #include // // -- 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(nsIPresShell* aPresShell, nsStyleContext* aContext) { return new (aPresShell) nsMathMLmmultiscriptsFrame(aContext); } NS_IMPL_FRAMEARENA_HELPERS(nsMathMLmmultiscriptsFrame) nsMathMLmmultiscriptsFrame::~nsMathMLmmultiscriptsFrame() { } 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 REC says: // The script element increments scriptlevel by 1, and sets // displaystyle to "false", within each of its arguments except base UpdatePresentationDataFromChildAt(1, -1, ~NS_MATHML_DISPLAYSTYLE, NS_MATHML_DISPLAYSTYLE); // 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. if (mContent->Tag() == nsGkAtoms::msup_) return NS_OK; int32_t count = 0; bool isSubScript = true; nsAutoTArray subScriptFrames; nsIFrame* childFrame = mFrames.FirstChild(); while (childFrame) { if (childFrame->GetContent()->Tag() == nsGkAtoms::mprescripts_) { // mprescripts frame } else if (0 == count) { // base frame } else { // super/subscript block if (isSubScript) { // subscript subScriptFrames.AppendElement(childFrame); } else { // superscript } 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(nsRenderingContext& aRenderingContext, bool aPlaceOrigin, nsHTMLReflowMetrics& aDesiredSize) { nscoord subScriptShift = 0; nscoord supScriptShift = 0; nsIAtom* tag = mContent->Tag(); // subscriptshift // // "Specifies the minimum amount to shift the baseline of subscript down; the // default is for the rendering agent to use its own positioning rules." // // values: length // default: automatic // // We use 0 as the default value so unitless values can be ignored. // As a minimum, negative values can be ignored. // nsAutoString value; if (tag != nsGkAtoms::msup_) { GetAttribute(mContent, mPresentationData.mstyle, nsGkAtoms::subscriptshift_, value); if (!value.IsEmpty()) { ParseNumericValue(value, &subScriptShift, 0, PresContext(), mStyleContext); } } // superscriptshift // // "Specifies the minimum amount to shift the baseline of superscript up; the // default is for the rendering agent to use its own positioning rules." // // values: length // default: automatic // // We use 0 as the default value so unitless values can be ignored. // As a minimum, negative values can be ignored. // if (tag != nsGkAtoms::msub_) { GetAttribute(mContent, mPresentationData.mstyle, nsGkAtoms::superscriptshift_, value); if (!value.IsEmpty()) { ParseNumericValue(value, &supScriptShift, 0, PresContext(), mStyleContext); } } // scriptspace from TeX for extra spacing after sup/subscript // (0.5pt in plain TeX) nscoord scriptSpace = nsPresContext::CSSPointsToAppUnits(0.5f); return PlaceMultiScript(PresContext(), aRenderingContext, aPlaceOrigin, aDesiredSize, this, subScriptShift, supScriptShift, scriptSpace); } // exported routine that both munderover and mmultiscripts share. // munderover uses this when movablelimits is set. nsresult nsMathMLmmultiscriptsFrame::PlaceMultiScript(nsPresContext* aPresContext, nsRenderingContext& aRenderingContext, bool aPlaceOrigin, nsHTMLReflowMetrics& aDesiredSize, nsMathMLContainerFrame* aFrame, nscoord aUserSubScriptShift, nscoord aUserSupScriptShift, nscoord aScriptSpace) { nsIAtom* tag = aFrame->GetContent()->Tag(); // 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 (tag == nsGkAtoms::mover_) tag = nsGkAtoms::msup_; else if (tag == nsGkAtoms::munder_) tag = nsGkAtoms::msub_; else if (tag == nsGkAtoms::munderover_) tag = nsGkAtoms::msubsup_; nsBoundingMetrics bmFrame; nsHTMLReflowMetrics frameSize; nscoord minShiftFromXHeight, subDrop, supDrop; //////////////////////////////////////// // Initialize super/sub shifts that // depend only on the current font //////////////////////////////////////// nsIFrame* baseFrame = aFrame->GetFirstPrincipalChild(); if (!baseFrame) { if (tag == nsGkAtoms::mmultiscripts_) aFrame->ReportErrorToConsole("NoBase"); else aFrame->ReportChildCountError(); return aFrame->ReflowError(aRenderingContext, aDesiredSize); } // get x-height (an ex) const nsStyleFont* font = aFrame->StyleFont(); nsRefPtr fm; nsLayoutUtils::GetFontMetricsForFrame(baseFrame, getter_AddRefs(fm)); aRenderingContext.SetFont(fm); nscoord xHeight = fm->XHeight(); nscoord ruleSize; GetRuleThickness (aRenderingContext, fm, ruleSize); // force the scriptSpace to be at least 1 pixel nscoord onePixel = nsPresContext::CSSPixelsToAppUnits(1); aScriptSpace = std::max(onePixel, aScriptSpace); ///////////////////////////////////// // first the shift for the subscript // 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); nscoord subScriptShift; 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 // 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 nsPresentationData presentationData; aFrame->GetPresentationData(presentationData); nscoord supScriptShift; if ( font->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; } if (0 < aUserSupScriptShift) { // the user has set the supscriptshift attribute supScriptShift = std::max(supScriptShift, aUserSupScriptShift); } //////////////////////////////////// // Get the children's sizes //////////////////////////////////// nscoord width = 0, prescriptsWidth = 0, rightBearing = 0; nscoord minSubScriptShift = 0, minSupScriptShift = 0; nscoord trySubScriptShift = subScriptShift; nscoord trySupScriptShift = supScriptShift; nscoord maxSubScriptShift = subScriptShift; nscoord maxSupScriptShift = supScriptShift; nsHTMLReflowMetrics baseSize; nsHTMLReflowMetrics subScriptSize; nsHTMLReflowMetrics supScriptSize; nsHTMLReflowMetrics multiSubSize, multiSupSize; 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.ascent = multiSupSize.ascent = -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; bool foundNoneTag = false; // 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->GetFirstPrincipalChild(); while (childFrame) { nsIAtom* childTag = childFrame->GetContent()->Tag(); if (childTag == nsGkAtoms::mprescripts_) { if (tag != nsGkAtoms::mmultiscripts_) { if (aPlaceOrigin) { aFrame->ReportInvalidChildError(childTag); } return aFrame->ReflowError(aRenderingContext, aDesiredSize); } if (prescriptsFrame) { // duplicate found // report an error, encourage people to get their markups in order if (aPlaceOrigin) { aFrame->ReportErrorToConsole("DuplicateMprescripts"); } return aFrame->ReflowError(aRenderingContext, aDesiredSize); } if (!isSubScript) { if (aPlaceOrigin) { aFrame->ReportErrorToConsole("SubSupMismatch"); } return aFrame->ReflowError(aRenderingContext, aDesiredSize); } prescriptsFrame = childFrame; firstPrescriptsPair = true; } else if (0 == count) { // base if (childTag == nsGkAtoms::none) { if (tag == nsGkAtoms::mmultiscripts_) { if (aPlaceOrigin) { aFrame->ReportErrorToConsole("NoBase"); } return aFrame->ReflowError(aRenderingContext, aDesiredSize); } else { //A different error message is triggered later for the other tags foundNoneTag = true; } } 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 // XXX need italic correction only *if* there are postscripts ? boundingMetrics.width = bmBase.width + italicCorrection; boundingMetrics.rightBearing = bmBase.rightBearing; boundingMetrics.leftBearing = bmBase.leftBearing; // until overwritten } else { // super/subscript block if ( childTag == nsGkAtoms::none) { foundNoneTag = true; } if (isSubScript) { // subscript subScriptFrame = childFrame; GetReflowAndBoundingMetricsFor(subScriptFrame, subScriptSize, bmSubScript); // get the subdrop from the subscript font GetSubDropFromChild (subScriptFrame, subDrop); // parameter v, Rule 18a, App. G, TeXbook minSubScriptShift = bmBase.descent + subDrop; trySubScriptShift = std::max(minSubScriptShift,subScriptShift); multiSubSize.ascent = std::max(multiSubSize.ascent, subScriptSize.ascent); 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.ascent); if (bmSubScript.width) width = bmSubScript.width + aScriptSpace; rightBearing = bmSubScript.rightBearing; if (tag == nsGkAtoms::msub_) { boundingMetrics.rightBearing = boundingMetrics.width + rightBearing; boundingMetrics.width += width; // get min subscript shift limit from x-height // = h(x) - 4/5 * sigma_5, Rule 18b, App. G, TeXbook nscoord minShiftFromXHeight = (nscoord) (bmSubScript.ascent - (4.0f/5.0f) * xHeight); maxSubScriptShift = std::max(trySubScriptShift,minShiftFromXHeight); maxSubScriptShift = std::max(maxSubScriptShift, trySubScriptShift); trySubScriptShift = subScriptShift; } } else { // supscript supScriptFrame = childFrame; GetReflowAndBoundingMetricsFor(supScriptFrame, supScriptSize, bmSupScript); // get the supdrop from the supscript font GetSupDropFromChild (supScriptFrame, supDrop); // parameter u, Rule 18a, App. G, TeXbook minSupScriptShift = bmBase.ascent - supDrop; // get min supscript shift limit from x-height // = d(x) + 1/4 * sigma_5, Rule 18c, App. G, TeXbook minShiftFromXHeight = NSToCoordRound ((bmSupScript.descent + (1.0f/4.0f) * xHeight)); trySupScriptShift = std::max(minSupScriptShift, std::max(minShiftFromXHeight, supScriptShift)); multiSupSize.ascent = std::max(multiSupSize.ascent, supScriptSize.ascent); 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.ascent); if (bmSupScript.width) width = std::max(width, bmSupScript.width + aScriptSpace); rightBearing = std::max(rightBearing, bmSupScript.rightBearing); if (!prescriptsFrame) { // we are still looping over base & postscripts 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 gap = (trySupScriptShift - bmSupScript.descent) - (bmSubScript.ascent - trySubScriptShift); if (gap < 4.0f * ruleSize) { // adjust trySubScriptShift to get a gap of (4.0 * ruleSize) trySubScriptShift += NSToCoordRound ((4.0f * ruleSize) - gap); } // next we want to ensure that the bottom of the superscript // will be > (4/5) * x-height above baseline gap = NSToCoordRound ((4.0f/5.0f) * xHeight - (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 || (foundNoneTag && tag != nsGkAtoms::mmultiscripts_) || (!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 (foundNoneTag && tag != nsGkAtoms::mmultiscripts_) { aFrame->ReportInvalidChildError(nsGkAtoms::none); } else if (!baseFrame) { aFrame->ReportErrorToConsole("NoBase"); } else { aFrame->ReportErrorToConsole("SubSupMismatch"); } } return aFrame->ReflowError(aRenderingContext, 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.ascent = std::max(baseSize.ascent, std::max(multiSubSize.ascent - maxSubScriptShift, multiSupSize.ascent + maxSupScriptShift)); aDesiredSize.height = aDesiredSize.ascent + std::max(baseSize.height - baseSize.ascent, std::max(multiSubSize.height + maxSubScriptShift, multiSupSize.height - maxSupScriptShift)); aDesiredSize.width = boundingMetrics.width; aDesiredSize.mBoundingMetrics = boundingMetrics; aFrame->SetReference(nsPoint(0, aDesiredSize.ascent)); ////////////////// // 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; do { if (!childFrame) { // end of prescripts, // place the base ... childFrame = baseFrame; dy = aDesiredSize.ascent - baseSize.ascent; FinishReflowChild (baseFrame, aPresContext, nullptr, baseSize, aFrame->MirrorIfRTL(aDesiredSize.width, baseSize.width, dx), dy, 0); dx += bmBase.width + italicCorrection; } else if (prescriptsFrame != childFrame) { // 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); // center w.r.t. largest width width = std::max(subScriptSize.width, supScriptSize.width); if (subScriptFrame) { dy = aDesiredSize.ascent - subScriptSize.ascent + maxSubScriptShift; FinishReflowChild (subScriptFrame, aPresContext, nullptr, subScriptSize, aFrame->MirrorIfRTL(aDesiredSize.width, subScriptSize.width, dx + (width-subScriptSize.width)/2), dy, 0); } if (supScriptFrame) { dy = aDesiredSize.ascent - supScriptSize.ascent - maxSupScriptShift; FinishReflowChild (supScriptFrame, aPresContext, nullptr, supScriptSize, aFrame->MirrorIfRTL(aDesiredSize.width, supScriptSize.width, dx + (width-supScriptSize.width)/2), dy, 0); } dx += width + aScriptSpace; } } childFrame = childFrame->GetNextSibling(); } while (prescriptsFrame != childFrame); } return NS_OK; }