nsresult
nsMathMLmfracFrame::PlaceInternal(nsRenderingContext& aRenderingContext,
bool aPlaceOrigin,
nsHTMLReflowMetrics& aDesiredSize,
bool aWidthOnly)
{
////////////////////////////////////
// Get the children's desired sizes
nsBoundingMetrics bmNum, bmDen;
nsHTMLReflowMetrics sizeNum;
nsHTMLReflowMetrics sizeDen;
nsIFrame* frameDen = nullptr;
nsIFrame* frameNum = mFrames.FirstChild();
if (frameNum)
frameDen = frameNum->GetNextSibling();
if (!frameNum || !frameDen || frameDen->GetNextSibling()) {
// report an error, encourage people to get their markups in order
if (aPlaceOrigin) {
ReportChildCountError();
}
return ReflowError(aRenderingContext, aDesiredSize);
}
GetReflowAndBoundingMetricsFor(frameNum, sizeNum, bmNum);
GetReflowAndBoundingMetricsFor(frameDen, sizeDen, bmDen);
nsPresContext* presContext = PresContext();
nscoord onePixel = nsPresContext::CSSPixelsToAppUnits(1);
nsRefPtr<nsFontMetrics> fm;
nsLayoutUtils::GetFontMetricsForFrame(this, getter_AddRefs(fm));
aRenderingContext.SetFont(fm);
nscoord defaultRuleThickness, axisHeight;
GetRuleThickness(aRenderingContext, fm, defaultRuleThickness);
GetAxisHeight(aRenderingContext, fm, axisHeight);
nsEmbellishData coreData;
GetEmbellishDataFrom(mEmbellishData.coreFrame, coreData);
// see if the linethickness attribute is there
nsAutoString value;
GetAttribute(mContent, mPresentationData.mstyle, nsGkAtoms::linethickness_,
value);
mLineThickness = CalcLineThickness(presContext, mStyleContext, value,
onePixel, defaultRuleThickness);
// bevelled attribute
GetAttribute(mContent, mPresentationData.mstyle, nsGkAtoms::bevelled_,
value);
mIsBevelled = value.EqualsLiteral("true");
if (!mIsBevelled) {
mLineRect.height = mLineThickness;
// by default, leave at least one-pixel padding at either end, or use
// lspace & rspace that may come from <mo> if we are an embellished
// container (we fetch values from the core since they may use units that
// depend on style data, and style changes could have occurred in the
// core since our last visit there)
nscoord leftSpace = std::max(onePixel,
NS_MATHML_IS_RTL(mPresentationData.flags) ?
coreData.trailingSpace : coreData.leadingSpace);
nscoord rightSpace = std::max(onePixel,
NS_MATHML_IS_RTL(mPresentationData.flags) ?
coreData.leadingSpace : coreData.trailingSpace);
//////////////////
// Get shifts
nscoord numShift = 0;
nscoord denShift = 0;
// Rule 15b, App. G, TeXbook
nscoord numShift1, numShift2, numShift3;
nscoord denShift1, denShift2;
GetNumeratorShifts(fm, numShift1, numShift2, numShift3);
GetDenominatorShifts(fm, denShift1, denShift2);
if (NS_MATHML_IS_DISPLAYSTYLE(mPresentationData.flags)) {
// C > T
numShift = numShift1;
denShift = denShift1;
}
else {
numShift = (0 < mLineRect.height) ? numShift2 : numShift3;
denShift = denShift2;
}
nscoord minClearance = 0;
nscoord actualClearance = 0;
nscoord actualRuleThickness = mLineThickness;
if (0 == actualRuleThickness) {
// Rule 15c, App. G, TeXbook
// min clearance between numerator and denominator
minClearance = (NS_MATHML_IS_DISPLAYSTYLE(mPresentationData.flags)) ?
7 * defaultRuleThickness : 3 * defaultRuleThickness;
actualClearance =
(numShift - bmNum.descent) - (bmDen.ascent - denShift);
// actualClearance should be >= minClearance
if (actualClearance < minClearance) {
nscoord halfGap = (minClearance - actualClearance)/2;
numShift += halfGap;
denShift += halfGap;
}
}
else {
// Rule 15d, App. G, TeXbook
// min clearance between numerator or denominator and middle of bar
// TeX has a different interpretation of the thickness.
// Try $a \above10pt b$ to see. Here is what TeX does:
// minClearance = (NS_MATHML_IS_DISPLAYSTYLE(mPresentationData.flags)) ?
// 3 * actualRuleThickness : actualRuleThickness;
// we slightly depart from TeX here. We use the defaultRuleThickness instead
// of the value coming from the linethickness attribute, i.e., we recover what
// TeX does if the user hasn't set linethickness. But when the linethickness
// is set, we avoid the wide gap problem.
minClearance = (NS_MATHML_IS_DISPLAYSTYLE(mPresentationData.flags)) ?
3 * defaultRuleThickness : defaultRuleThickness + onePixel;
// adjust numShift to maintain minClearance if needed
actualClearance =
(numShift - bmNum.descent) - (axisHeight + actualRuleThickness/2);
if (actualClearance < minClearance) {
numShift += (minClearance - actualClearance);
}
// adjust denShift to maintain minClearance if needed
actualClearance =
(axisHeight - actualRuleThickness/2) - (bmDen.ascent - denShift);
if (actualClearance < minClearance) {
denShift += (minClearance - actualClearance);
}
}
//////////////////
// Place Children
// XXX Need revisiting the width. TeX uses the exact width
// e.g. in $$\huge\frac{\displaystyle\int}{i}$$
nscoord width = std::max(bmNum.width, bmDen.width);
nscoord dxNum = leftSpace + (width - sizeNum.width)/2;
nscoord dxDen = leftSpace + (width - sizeDen.width)/2;
width += leftSpace + rightSpace;
// see if the numalign attribute is there
GetAttribute(mContent, mPresentationData.mstyle, nsGkAtoms::numalign_,
value);
if (value.EqualsLiteral("left"))
dxNum = leftSpace;
else if (value.EqualsLiteral("right"))
dxNum = width - rightSpace - sizeNum.width;
// see if the denomalign attribute is there
GetAttribute(mContent, mPresentationData.mstyle, nsGkAtoms::denomalign_,
value);
if (value.EqualsLiteral("left"))
dxDen = leftSpace;
else if (value.EqualsLiteral("right"))
dxDen = width - rightSpace - sizeDen.width;
mBoundingMetrics.rightBearing =
std::max(dxNum + bmNum.rightBearing, dxDen + bmDen.rightBearing);
if (mBoundingMetrics.rightBearing < width - rightSpace)
mBoundingMetrics.rightBearing = width - rightSpace;
mBoundingMetrics.leftBearing =
std::min(dxNum + bmNum.leftBearing, dxDen + bmDen.leftBearing);
if (mBoundingMetrics.leftBearing > leftSpace)
mBoundingMetrics.leftBearing = leftSpace;
mBoundingMetrics.ascent = bmNum.ascent + numShift;
mBoundingMetrics.descent = bmDen.descent + denShift;
mBoundingMetrics.width = width;
aDesiredSize.ascent = sizeNum.ascent + numShift;
aDesiredSize.height = aDesiredSize.ascent +
sizeDen.height - sizeDen.ascent + denShift;
aDesiredSize.width = mBoundingMetrics.width;
aDesiredSize.mBoundingMetrics = mBoundingMetrics;
mReference.x = 0;
mReference.y = aDesiredSize.ascent;
if (aPlaceOrigin) {
nscoord dy;
// place numerator
dy = 0;
FinishReflowChild(frameNum, presContext, nullptr, sizeNum, dxNum, dy, 0);
// place denominator
dy = aDesiredSize.height - sizeDen.height;
FinishReflowChild(frameDen, presContext, nullptr, sizeDen, dxDen, dy, 0);
// place the fraction bar - dy is top of bar
dy = aDesiredSize.ascent - (axisHeight + actualRuleThickness/2);
mLineRect.SetRect(leftSpace, dy, width - (leftSpace + rightSpace),
actualRuleThickness);
}
} else {
nscoord numShift = 0.0;
nscoord denShift = 0.0;
nscoord padding = 3 * defaultRuleThickness;
nscoord slashRatio = 3;
// Define the constant used in the expression of the maximum width
nscoord em = fm->EmHeight();
nscoord slashMaxWidthConstant = 2 * em;
// For large line thicknesses the minimum slash height is limited to the
// largest expected height of a fraction
nscoord slashMinHeight = slashRatio *
std::min(2 * mLineThickness, slashMaxWidthConstant);
nscoord leadingSpace = std::max(padding, coreData.leadingSpace);
nscoord trailingSpace = std::max(padding, coreData.trailingSpace);
nscoord delta;
// ___________
// | | /
// {|-NUMERATOR-| /
// {|___________| S
// { L
// numShift{ A
// ------------------------------------------------------- baseline
// S _____________ } denShift
// H | |}
// / |-DENOMINATOR-|}
// / |_____________|
//
// first, ensure that the top of the numerator is at least as high as the
// top of the denominator (and the reverse for the bottoms)
delta = std::max(bmDen.ascent - bmNum.ascent,
bmNum.descent - bmDen.descent) / 2;
if (delta > 0) {
numShift += delta;
denShift += delta;
}
if (NS_MATHML_IS_DISPLAYSTYLE(mPresentationData.flags)) {
delta = std::min(bmDen.ascent + bmDen.descent,
bmNum.ascent + bmNum.descent) / 2;
numShift += delta;
denShift += delta;
} else {
nscoord xHeight = fm->XHeight();
numShift += xHeight / 2;
denShift += xHeight / 4;
}
// Set the ascent/descent of our BoundingMetrics.
mBoundingMetrics.ascent = bmNum.ascent + numShift;
mBoundingMetrics.descent = bmDen.descent + denShift;
// At this point the height of the slash is
// mBoundingMetrics.ascent + mBoundingMetrics.descent
// Ensure that it is greater than slashMinHeight
delta = (slashMinHeight -
(mBoundingMetrics.ascent + mBoundingMetrics.descent)) / 2;
if (delta > 0) {
mBoundingMetrics.ascent += delta;
mBoundingMetrics.descent += delta;
}
// Set the width of the slash
if (aWidthOnly) {
mLineRect.width = mLineThickness + slashMaxWidthConstant;
} else {
mLineRect.width = mLineThickness +
std::min(slashMaxWidthConstant,
(mBoundingMetrics.ascent + mBoundingMetrics.descent) /
slashRatio);
}
// Set horizontal bounding metrics
if (NS_MATHML_IS_RTL(mPresentationData.flags)) {
mBoundingMetrics.leftBearing = trailingSpace + bmDen.leftBearing;
mBoundingMetrics.rightBearing = trailingSpace + bmDen.width + mLineRect.width + bmNum.rightBearing;
} else {
mBoundingMetrics.leftBearing = leadingSpace + bmNum.leftBearing;
mBoundingMetrics.rightBearing = leadingSpace + bmNum.width + mLineRect.width + bmDen.rightBearing;
}
mBoundingMetrics.width =
leadingSpace + bmNum.width + mLineRect.width + bmDen.width +
trailingSpace;
// Set aDesiredSize
aDesiredSize.ascent = mBoundingMetrics.ascent + padding;
aDesiredSize.height =
mBoundingMetrics.ascent + mBoundingMetrics.descent + 2 * padding;
aDesiredSize.width = mBoundingMetrics.width;
aDesiredSize.mBoundingMetrics = mBoundingMetrics;
mReference.x = 0;
mReference.y = aDesiredSize.ascent;
if (aPlaceOrigin) {
nscoord dx, dy;
// place numerator
dx = MirrorIfRTL(aDesiredSize.width, sizeNum.width,
leadingSpace);
dy = aDesiredSize.ascent - numShift - sizeNum.ascent;
FinishReflowChild(frameNum, presContext, nullptr, sizeNum, dx, dy, 0);
// place the fraction bar
dx = MirrorIfRTL(aDesiredSize.width, mLineRect.width,
leadingSpace + bmNum.width);
dy = aDesiredSize.ascent - mBoundingMetrics.ascent;
mLineRect.SetRect(dx, dy,
mLineRect.width, aDesiredSize.height - 2 * padding);
// place denominator
dx = MirrorIfRTL(aDesiredSize.width, sizeDen.width,
leadingSpace + bmNum.width + mLineRect.width);
dy = aDesiredSize.ascent + denShift - sizeDen.ascent;
FinishReflowChild(frameDen, presContext, nullptr, sizeDen, dx, dy, 0);
}
}
return NS_OK;
}
/* virtual */ nsresult
nsMathMLmmultiscriptsFrame::Place(nsRenderingContext& aRenderingContext,
bool aPlaceOrigin,
nsHTMLReflowMetrics& aDesiredSize)
{
////////////////////////////////////
// Get the children's desired sizes
nscoord minShiftFromXHeight, subDrop, supDrop;
////////////////////////////////////////
// Initialize super/sub shifts that
// depend only on the current font
////////////////////////////////////////
ProcessAttributes();
// get x-height (an ex)
const nsStyleFont* font = GetStyleFont();
nsRefPtr<nsFontMetrics> fm;
nsLayoutUtils::GetFontMetricsForFrame(this, getter_AddRefs(fm));
aRenderingContext.SetFont(fm);
nscoord xHeight = fm->XHeight();
nscoord ruleSize;
GetRuleThickness (aRenderingContext, fm, ruleSize);
// scriptspace from TeX for extra spacing after sup/subscript (0.5pt in plain TeX)
// forced to be at least 1 pixel here
nscoord onePixel = nsPresContext::CSSPixelsToAppUnits(1);
nscoord scriptSpace = NS_MAX(nsPresContext::CSSPointsToAppUnits(0.5f), onePixel);
/////////////////////////////////////
// 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);
if (0 < mSubScriptShift) {
// the user has set the subscriptshift attribute
float scaler = ((float) subScriptShift2) / subScriptShift1;
subScriptShift1 = NS_MAX(subScriptShift1, mSubScriptShift);
subScriptShift2 = NSToCoordRound(scaler * subScriptShift1);
}
// the font dependent shift
nscoord subScriptShift = NS_MAX(subScriptShift1,subScriptShift2);
/////////////////////////////////////
// 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);
if (0 < mSupScriptShift) {
// the user has set the superscriptshift attribute
float scaler2 = ((float) supScriptShift2) / supScriptShift1;
float scaler3 = ((float) supScriptShift3) / supScriptShift1;
supScriptShift1 = NS_MAX(supScriptShift1, mSupScriptShift);
supScriptShift2 = NSToCoordRound(scaler2 * supScriptShift1);
supScriptShift3 = NSToCoordRound(scaler3 * supScriptShift1);
}
// get sup script shift depending on current script level and display style
// Rule 18c, App. G, TeXbook
nscoord supScriptShift;
if ( font->mScriptLevel == 0 &&
NS_MATHML_IS_DISPLAYSTYLE(mPresentationData.flags) &&
!NS_MATHML_IS_COMPRESSED(mPresentationData.flags)) {
// Style D in TeXbook
supScriptShift = supScriptShift1;
}
else if (NS_MATHML_IS_COMPRESSED(mPresentationData.flags)) {
// Style C' in TeXbook = D',T',S',SS'
supScriptShift = supScriptShift3;
}
else {
// everything else = T,S,SS
supScriptShift = supScriptShift2;
}
////////////////////////////////////
// Get the children's sizes
////////////////////////////////////
nscoord width = 0, prescriptsWidth = 0, rightBearing = 0;
nsIFrame* mprescriptsFrame = nsnull; // frame of <mprescripts/>, if there.
bool isSubScript = false;
nscoord minSubScriptShift = 0, minSupScriptShift = 0;
nscoord trySubScriptShift = subScriptShift;
nscoord trySupScriptShift = supScriptShift;
nscoord maxSubScriptShift = subScriptShift;
nscoord maxSupScriptShift = supScriptShift;
PRInt32 count = 0;
nsHTMLReflowMetrics baseSize;
nsHTMLReflowMetrics subScriptSize;
nsHTMLReflowMetrics supScriptSize;
nsIFrame* baseFrame = nsnull;
nsIFrame* subScriptFrame = nsnull;
nsIFrame* supScriptFrame = nsnull;
bool firstPrescriptsPair = false;
nsBoundingMetrics bmBase, bmSubScript, bmSupScript;
nscoord italicCorrection = 0;
mBoundingMetrics.width = 0;
mBoundingMetrics.ascent = mBoundingMetrics.descent = -0x7FFFFFFF;
nscoord ascent = -0x7FFFFFFF, descent = -0x7FFFFFFF;
aDesiredSize.width = aDesiredSize.height = 0;
nsIFrame* childFrame = mFrames.FirstChild();
while (childFrame) {
if (childFrame->GetContent()->Tag() == nsGkAtoms::mprescripts_) {
if (mprescriptsFrame) {
// duplicate <mprescripts/> found
// report an error, encourage people to get their markups in order
return ReflowError(aRenderingContext, aDesiredSize);
}
mprescriptsFrame = childFrame;
firstPrescriptsPair = true;
}
else {
if (0 == count) {
// base
baseFrame = childFrame;
GetReflowAndBoundingMetricsFor(baseFrame, baseSize, bmBase);
GetItalicCorrection(bmBase, italicCorrection);
// for the superscript, we always add "a little to spare"
italicCorrection += onePixel;
// we update mBoundingMetrics.{ascent,descent} with that
// of the baseFrame only after processing all the sup/sub pairs
// XXX need italic correction only *if* there are postscripts ?
mBoundingMetrics.width = bmBase.width + italicCorrection;
mBoundingMetrics.rightBearing = bmBase.rightBearing;
mBoundingMetrics.leftBearing = bmBase.leftBearing; // until overwritten
}
else {
// super/subscript block
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 = NS_MAX(minSubScriptShift,subScriptShift);
mBoundingMetrics.descent =
NS_MAX(mBoundingMetrics.descent,bmSubScript.descent);
descent = NS_MAX(descent,subScriptSize.height - subScriptSize.ascent);
width = bmSubScript.width + scriptSpace;
rightBearing = bmSubScript.rightBearing;
}
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 =
NS_MAX(minSupScriptShift,NS_MAX(minShiftFromXHeight,supScriptShift));
mBoundingMetrics.ascent =
NS_MAX(mBoundingMetrics.ascent,bmSupScript.ascent);
ascent = NS_MAX(ascent,supScriptSize.ascent);
width = NS_MAX(width, bmSupScript.width + scriptSpace);
rightBearing = NS_MAX(rightBearing, bmSupScript.rightBearing);
if (!mprescriptsFrame) { // we are still looping over base & postscripts
mBoundingMetrics.rightBearing = mBoundingMetrics.width + rightBearing;
mBoundingMetrics.width += width;
}
else {
prescriptsWidth += width;
if (firstPrescriptsPair) {
firstPrescriptsPair = false;
mBoundingMetrics.leftBearing =
NS_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
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 > 0.0f) {
trySupScriptShift += gap;
trySubScriptShift -= gap;
}
maxSubScriptShift = NS_MAX(maxSubScriptShift, trySubScriptShift);
maxSupScriptShift = NS_MAX(maxSupScriptShift, trySupScriptShift);
trySubScriptShift = subScriptShift;
trySupScriptShift = supScriptShift;
}
}
isSubScript = !isSubScript;
}
count++;
childFrame = childFrame->GetNextSibling();
}
// note: width=0 if all sup-sub pairs match correctly
if ((0 != width) || !baseFrame || !subScriptFrame || !supScriptFrame) {
// report an error, encourage people to get their markups in order
return ReflowError(aRenderingContext, aDesiredSize);
}
// we left out the width of prescripts, so ...
mBoundingMetrics.rightBearing += prescriptsWidth;
mBoundingMetrics.width += prescriptsWidth;
// we left out the base during our bounding box updates, so ...
mBoundingMetrics.ascent =
NS_MAX(mBoundingMetrics.ascent+maxSupScriptShift,bmBase.ascent);
mBoundingMetrics.descent =
NS_MAX(mBoundingMetrics.descent+maxSubScriptShift,bmBase.descent);
// get the reflow metrics ...
aDesiredSize.ascent =
NS_MAX(ascent+maxSupScriptShift,baseSize.ascent);
aDesiredSize.height = aDesiredSize.ascent +
NS_MAX(descent+maxSubScriptShift,baseSize.height - baseSize.ascent);
aDesiredSize.width = mBoundingMetrics.width;
aDesiredSize.mBoundingMetrics = mBoundingMetrics;
mReference.x = 0;
mReference.y = 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 <prescripts/>
if (aPlaceOrigin) {
nscoord dx = 0, dy = 0;
count = 0;
childFrame = mprescriptsFrame;
do {
if (!childFrame) { // end of prescripts,
// place the base ...
childFrame = baseFrame;
dy = aDesiredSize.ascent - baseSize.ascent;
FinishReflowChild (baseFrame, PresContext(), nsnull, baseSize,
MirrorIfRTL(aDesiredSize.width,
baseSize.width,
dx),
dy, 0);
dx += bmBase.width + italicCorrection;
}
else if (mprescriptsFrame != childFrame) {
// process each sup/sub pair
if (0 == count) {
subScriptFrame = childFrame;
count = 1;
}
else if (1 == count) {
supScriptFrame = childFrame;
count = 0;
// get the ascent/descent of sup/subscripts stored in their rects
// rect.x = descent, rect.y = ascent
GetReflowAndBoundingMetricsFor(subScriptFrame, subScriptSize, bmSubScript);
GetReflowAndBoundingMetricsFor(supScriptFrame, supScriptSize, bmSupScript);
// center w.r.t. largest width
width = NS_MAX(subScriptSize.width, supScriptSize.width);
dy = aDesiredSize.ascent - subScriptSize.ascent +
maxSubScriptShift;
FinishReflowChild (subScriptFrame, PresContext(), nsnull,
subScriptSize,
MirrorIfRTL(aDesiredSize.width,
subScriptSize.width,
dx + (width-subScriptSize.width)/2),
dy, 0);
dy = aDesiredSize.ascent - supScriptSize.ascent -
maxSupScriptShift;
FinishReflowChild (supScriptFrame, PresContext(), nsnull,
supScriptSize,
MirrorIfRTL(aDesiredSize.width,
supScriptSize.width,
dx + (width-supScriptSize.width)/2),
dy, 0);
dx += width + scriptSpace;
}
}
childFrame = childFrame->GetNextSibling();
} while (mprescriptsFrame != childFrame);
}
return NS_OK;
}
NS_IMETHODIMP
nsMathMLmrootFrame::Reflow(nsPresContext* aPresContext,
nsHTMLReflowMetrics& aDesiredSize,
const nsHTMLReflowState& aReflowState,
nsReflowStatus& aStatus)
{
nsresult rv = NS_OK;
nsSize availSize(aReflowState.ComputedWidth(), NS_UNCONSTRAINEDSIZE);
nsReflowStatus childStatus;
aDesiredSize.Width() = aDesiredSize.Height() = 0;
aDesiredSize.SetTopAscent(0);
nsBoundingMetrics bmSqr, bmBase, bmIndex;
nsRenderingContext& renderingContext = *aReflowState.rendContext;
//////////////////
// Reflow Children
int32_t count = 0;
nsIFrame* baseFrame = nullptr;
nsIFrame* indexFrame = nullptr;
nsHTMLReflowMetrics baseSize(aReflowState.GetWritingMode());
nsHTMLReflowMetrics indexSize(aReflowState.GetWritingMode());
nsIFrame* childFrame = mFrames.FirstChild();
while (childFrame) {
// ask our children to compute their bounding metrics
nsHTMLReflowMetrics childDesiredSize(aReflowState.GetWritingMode(),
aDesiredSize.mFlags
| NS_REFLOW_CALC_BOUNDING_METRICS);
nsHTMLReflowState childReflowState(aPresContext, aReflowState,
childFrame, availSize);
rv = ReflowChild(childFrame, aPresContext,
childDesiredSize, childReflowState, childStatus);
//NS_ASSERTION(NS_FRAME_IS_COMPLETE(childStatus), "bad status");
if (NS_FAILED(rv)) {
// Call DidReflow() for the child frames we successfully did reflow.
DidReflowChildren(mFrames.FirstChild(), childFrame);
return rv;
}
if (0 == count) {
// base
baseFrame = childFrame;
baseSize = childDesiredSize;
bmBase = childDesiredSize.mBoundingMetrics;
}
else if (1 == count) {
// index
indexFrame = childFrame;
indexSize = childDesiredSize;
bmIndex = childDesiredSize.mBoundingMetrics;
}
count++;
childFrame = childFrame->GetNextSibling();
}
if (2 != count) {
// report an error, encourage people to get their markups in order
ReportChildCountError();
rv = ReflowError(renderingContext, aDesiredSize);
aStatus = NS_FRAME_COMPLETE;
NS_FRAME_SET_TRUNCATION(aStatus, aReflowState, aDesiredSize);
// Call DidReflow() for the child frames we successfully did reflow.
DidReflowChildren(mFrames.FirstChild(), childFrame);
return rv;
}
////////////
// Prepare the radical symbol and the overline bar
nsRefPtr<nsFontMetrics> fm;
nsLayoutUtils::GetFontMetricsForFrame(this, getter_AddRefs(fm));
renderingContext.SetFont(fm);
// For radical glyphs from TeX fonts and some of the radical glyphs from
// Mathematica fonts, the thickness of the overline can be obtained from the
// ascent of the glyph. Most fonts however have radical glyphs above the
// baseline so no assumption can be made about the meaning of the ascent.
nscoord ruleThickness, leading, em;
GetRuleThickness(renderingContext, fm, ruleThickness);
char16_t one = '1';
nsBoundingMetrics bmOne = renderingContext.GetBoundingMetrics(&one, 1);
// get the leading to be left at the top of the resulting frame
// this seems more reliable than using fm->GetLeading() on suspicious fonts
GetEmHeight(fm, em);
leading = nscoord(0.2f * em);
// Rule 11, App. G, TeXbook
// psi = clearance between rule and content
nscoord phi = 0, psi = 0;
if (StyleFont()->mMathDisplay == NS_MATHML_DISPLAYSTYLE_BLOCK)
phi = fm->XHeight();
else
phi = ruleThickness;
psi = ruleThickness + phi/4;
// built-in: adjust clearance psi to emulate \mathstrut using '1' (TexBook, p.131)
if (bmOne.ascent > bmBase.ascent)
psi += bmOne.ascent - bmBase.ascent;
// make sure that the rule appears on on screen
nscoord onePixel = nsPresContext::CSSPixelsToAppUnits(1);
if (ruleThickness < onePixel) {
ruleThickness = onePixel;
}
// adjust clearance psi to get an exact number of pixels -- this
// gives a nicer & uniform look on stacked radicals (bug 130282)
nscoord delta = psi % onePixel;
if (delta)
psi += onePixel - delta; // round up
// Stretch the radical symbol to the appropriate height if it is not big enough.
nsBoundingMetrics contSize = bmBase;
contSize.descent = bmBase.ascent + bmBase.descent + psi;
contSize.ascent = ruleThickness;
// height(radical) should be >= height(base) + psi + ruleThickness
nsBoundingMetrics radicalSize;
mSqrChar.Stretch(aPresContext, renderingContext,
NS_STRETCH_DIRECTION_VERTICAL,
contSize, radicalSize,
NS_STRETCH_LARGER,
StyleVisibility()->mDirection);
// radicalSize have changed at this point, and should match with
// the bounding metrics of the char
mSqrChar.GetBoundingMetrics(bmSqr);
// Update the desired size for the container (like msqrt, index is not yet included)
// the baseline will be that of the base.
mBoundingMetrics.ascent = bmBase.ascent + psi + ruleThickness;
mBoundingMetrics.descent =
std::max(bmBase.descent,
(bmSqr.ascent + bmSqr.descent - mBoundingMetrics.ascent));
mBoundingMetrics.width = bmSqr.width + bmBase.width;
mBoundingMetrics.leftBearing = bmSqr.leftBearing;
mBoundingMetrics.rightBearing = bmSqr.width +
std::max(bmBase.width, bmBase.rightBearing); // take also care of the rule
aDesiredSize.SetTopAscent(mBoundingMetrics.ascent + leading);
aDesiredSize.Height() = aDesiredSize.TopAscent() +
std::max(baseSize.Height() - baseSize.TopAscent(),
mBoundingMetrics.descent + ruleThickness);
aDesiredSize.Width() = mBoundingMetrics.width;
/////////////
// Re-adjust the desired size to include the index.
// the index is raised by some fraction of the height
// of the radical, see \mroot macro in App. B, TexBook
nscoord raiseIndexDelta = NSToCoordRound(0.6f * (bmSqr.ascent + bmSqr.descent));
nscoord indexRaisedAscent = mBoundingMetrics.ascent // top of radical
- (bmSqr.ascent + bmSqr.descent) // to bottom of radical
+ raiseIndexDelta + bmIndex.ascent + bmIndex.descent; // to top of raised index
nscoord indexClearance = 0;
if (mBoundingMetrics.ascent < indexRaisedAscent) {
indexClearance =
indexRaisedAscent - mBoundingMetrics.ascent; // excess gap introduced by a tall index
mBoundingMetrics.ascent = indexRaisedAscent;
nscoord descent = aDesiredSize.Height() - aDesiredSize.TopAscent();
aDesiredSize.SetTopAscent(mBoundingMetrics.ascent + leading);
aDesiredSize.Height() = aDesiredSize.TopAscent() + descent;
}
nscoord dxIndex, dxSqr;
GetRadicalXOffsets(bmIndex.width, bmSqr.width, fm, &dxIndex, &dxSqr);
mBoundingMetrics.width = dxSqr + bmSqr.width + bmBase.width;
mBoundingMetrics.leftBearing =
std::min(dxIndex + bmIndex.leftBearing, dxSqr + bmSqr.leftBearing);
mBoundingMetrics.rightBearing = dxSqr + bmSqr.width +
std::max(bmBase.width, bmBase.rightBearing);
aDesiredSize.Width() = mBoundingMetrics.width;
aDesiredSize.mBoundingMetrics = mBoundingMetrics;
GatherAndStoreOverflow(&aDesiredSize);
// place the index
nscoord dx = dxIndex;
nscoord dy = aDesiredSize.TopAscent() - (indexRaisedAscent + indexSize.TopAscent() - bmIndex.ascent);
FinishReflowChild(indexFrame, aPresContext, indexSize, nullptr,
MirrorIfRTL(aDesiredSize.Width(), indexSize.Width(), dx),
dy, 0);
// place the radical symbol and the radical bar
dx = dxSqr;
dy = indexClearance + leading; // leave a leading at the top
mSqrChar.SetRect(nsRect(MirrorIfRTL(aDesiredSize.Width(), bmSqr.width, dx),
dy, bmSqr.width, bmSqr.ascent + bmSqr.descent));
dx += bmSqr.width;
mBarRect.SetRect(MirrorIfRTL(aDesiredSize.Width(), bmBase.width, dx),
dy, bmBase.width, ruleThickness);
// place the base
dy = aDesiredSize.TopAscent() - baseSize.TopAscent();
FinishReflowChild(baseFrame, aPresContext, baseSize, nullptr,
MirrorIfRTL(aDesiredSize.Width(), baseSize.Width(), dx),
dy, 0);
mReference.x = 0;
mReference.y = aDesiredSize.TopAscent();
aStatus = NS_FRAME_COMPLETE;
NS_FRAME_SET_TRUNCATION(aStatus, aReflowState, aDesiredSize);
return NS_OK;
}
