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gecko-dev/layout/mathml/nsMathMLmmultiscriptsFrame.cpp

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27 KiB
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/* -*- 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/PresShell.h"
#include "mozilla/StaticPrefs_mathml.h"
#include "nsPresContext.h"
#include <algorithm>
#include "gfxContext.h"
#include "gfxMathTable.h"
#include "gfxTextRun.h"
using namespace mozilla;
//
// <mmultiscripts> -- attach prescripts and tensor indices to a base -
// implementation <msub> -- attach a subscript to a base - implementation
// <msubsup> -- attach a subscript-superscript pair to a base - implementation
// <msup> -- 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<nsIFrame*, 8> 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);
if (!StaticPrefs::mathml_script_shift_attributes_disabled()) {
// 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 (!mContent->IsMathMLElement(nsGkAtoms::msup_) &&
mContent->AsElement()->GetAttr(kNameSpaceID_None,
nsGkAtoms::subscriptshift_, value)) {
mContent->OwnerDoc()->WarnOnceAbout(
dom::Document::eMathML_DeprecatedScriptShiftAttributes);
ParseNumericValue(value, &subScriptShift, 0, PresContext(),
mComputedStyle, fontSizeInflation);
}
// 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 (!mContent->IsMathMLElement(nsGkAtoms::msub_) &&
mContent->AsElement()->GetAttr(kNameSpaceID_None,
nsGkAtoms::superscriptshift_, value)) {
mContent->OwnerDoc()->WarnOnceAbout(
dom::Document::eMathML_DeprecatedScriptShiftAttributes);
ParseNumericValue(value, &supScriptShift, 0, PresContext(),
mComputedStyle, fontSizeInflation);
}
}
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->ReflowError(aDrawTarget, aDesiredSize);
}
// get x-height (an ex)
const nsStyleFont* font = aFrame->StyleFont();
RefPtr<nsFontMetrics> fm =
nsLayoutUtils::GetFontMetricsForFrame(baseFrame, aFontSizeInflation);
nscoord xHeight = fm->XHeight();
nscoord oneDevPixel = fm->AppUnitsPerDevPixel();
gfxFont* 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->mScriptLevel == 0 &&
font->mMathDisplay == NS_MATHML_DISPLAYSTYLE_BLOCK &&
!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 <mprescripts/>, 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;
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->PrincipalChildList().FirstChild();
while (childFrame) {
if (childFrame->GetContent()->IsMathMLElement(nsGkAtoms::mprescripts_)) {
if (tag != nsGkAtoms::mmultiscripts_) {
if (aPlaceOrigin) {
aFrame->ReportInvalidChildError(nsGkAtoms::mprescripts_);
}
return aFrame->ReflowError(aDrawTarget, aDesiredSize);
}
if (prescriptsFrame) {
// duplicate <mprescripts/> found
// report an error, encourage people to get their markups in order
if (aPlaceOrigin) {
aFrame->ReportErrorToConsole("DuplicateMprescripts");
}
return aFrame->ReflowError(aDrawTarget, aDesiredSize);
}
if (!isSubScript) {
if (aPlaceOrigin) {
aFrame->ReportErrorToConsole("SubSupMismatch");
}
return aFrame->ReflowError(aDrawTarget, aDesiredSize);
}
prescriptsFrame = childFrame;
firstPrescriptsPair = true;
} else if (0 == count) {
// base
if (childFrame->GetContent()->IsMathMLElement(nsGkAtoms::none)) {
if (tag == nsGkAtoms::mmultiscripts_) {
if (aPlaceOrigin) {
aFrame->ReportErrorToConsole("NoBase");
}
return aFrame->ReflowError(aDrawTarget, 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
boundingMetrics.width = bmBase.width;
boundingMetrics.rightBearing = bmBase.rightBearing;
boundingMetrics.leftBearing = bmBase.leftBearing; // until overwritten
} else {
// super/subscript block
if (childFrame->GetContent()->IsMathMLElement(nsGkAtoms::none)) {
foundNoneTag = true;
}
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 ||
(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(aDrawTarget, 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 <prescripts/>
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;
}
Ссылка в новой задаче Показать git blame Копировать постоянную ссылку