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Bug 961365 - Part 3: Use MATH constants for fractions and stacks. r=jfkthame

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This commit is contained in:
Frédéric Wang 2014-06-17 02:41:00 -04:00
parent 48d4f1ae3d
commit c9a9cf88b0
1 changed files with 81 additions and 30 deletions
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111
layout/mathml/nsMathMLmfracFrame.cpp
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@ -219,7 +219,15 @@ nsMathMLmfracFrame::PlaceInternal(nsRenderingContext& aRenderingContext,
aRenderingContext.SetFont(fm);
nscoord defaultRuleThickness, axisHeight;
GetRuleThickness(aRenderingContext, fm, defaultRuleThickness);
nscoord oneDevPixel = fm->AppUnitsPerDevPixel();
gfxFont* mathFont = fm->GetThebesFontGroup()->GetFirstMathFont();
if (mathFont) {
defaultRuleThickness =
mathFont->GetMathConstant(gfxFontEntry::FractionRuleThickness,
oneDevPixel);
} else {
GetRuleThickness(aRenderingContext, fm, defaultRuleThickness);
}
GetAxisHeight(aRenderingContext, fm, axisHeight);
bool outermostEmbellished = false;
@ -239,6 +247,8 @@ nsMathMLmfracFrame::PlaceInternal(nsRenderingContext& aRenderingContext,
mContent->GetAttr(kNameSpaceID_None, nsGkAtoms::bevelled_, value);
mIsBevelled = value.EqualsLiteral("true");
bool displayStyle = StyleFont()->mMathDisplay == NS_MATHML_DISPLAYSTYLE_BLOCK;
if (!mIsBevelled) {
mLineRect.height = mLineThickness;
@ -258,6 +268,8 @@ nsMathMLmfracFrame::PlaceInternal(nsRenderingContext& aRenderingContext,
coreData.leadingSpace : coreData.trailingSpace;
}
nscoord actualRuleThickness = mLineThickness;
//////////////////
// Get shifts
nscoord numShift = 0;
@ -269,28 +281,54 @@ nsMathMLmfracFrame::PlaceInternal(nsRenderingContext& aRenderingContext,
GetNumeratorShifts(fm, numShift1, numShift2, numShift3);
GetDenominatorShifts(fm, denShift1, denShift2);
if (StyleFont()->mMathDisplay == NS_MATHML_DISPLAYSTYLE_BLOCK) {
// 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) {
numShift = displayStyle ? numShift1 : numShift3;
denShift = displayStyle ? denShift1 : denShift2;
if (mathFont) {
numShift = mathFont->
GetMathConstant(displayStyle ?
gfxFontEntry::StackTopDisplayStyleShiftUp :
gfxFontEntry::StackTopShiftUp,
oneDevPixel);
denShift = mathFont->
GetMathConstant(displayStyle ?
gfxFontEntry::StackBottomDisplayStyleShiftDown :
gfxFontEntry::StackBottomShiftDown,
oneDevPixel);
}
} else {
numShift = displayStyle ? numShift1 : numShift2;
denShift = displayStyle ? denShift1 : denShift2;
if (mathFont) {
numShift = mathFont->
GetMathConstant(displayStyle ?
gfxFontEntry::FractionNumeratorDisplayStyleShiftUp :
gfxFontEntry::FractionNumeratorShiftUp,
oneDevPixel);
denShift = mathFont->
GetMathConstant(
displayStyle ?
gfxFontEntry::FractionDenominatorDisplayStyleShiftDown :
gfxFontEntry::FractionDenominatorShiftDown,
oneDevPixel);
}
}
if (0 == actualRuleThickness) {
// Rule 15c, App. G, TeXbook
// min clearance between numerator and denominator
minClearance = StyleFont()->mMathDisplay == NS_MATHML_DISPLAYSTYLE_BLOCK ?
nscoord minClearance = displayStyle ?
7 * defaultRuleThickness : 3 * defaultRuleThickness;
actualClearance =
if (mathFont) {
minClearance =
mathFont->GetMathConstant(displayStyle ?
gfxFontEntry::StackDisplayStyleGapMin :
gfxFontEntry::StackGapMin,
oneDevPixel);
}
nscoord actualClearance =
(numShift - bmNum.descent) - (bmDen.ascent - denShift);
// actualClearance should be >= minClearance
if (actualClearance < minClearance) {
@ -306,27 +344,40 @@ nsMathMLmfracFrame::PlaceInternal(nsRenderingContext& aRenderingContext,
// TeX has a different interpretation of the thickness.
// Try $a \above10pt b$ to see. Here is what TeX does:
// minClearance = StyleFont()->mMathDisplay == NS_MATHML_DISPLAYSTYLE_BLOCK
// ? 3 * actualRuleThickness : actualRuleThickness;
// minClearance = displayStyle ?
// 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 = StyleFont()->mMathDisplay == NS_MATHML_DISPLAYSTYLE_BLOCK ?
3 * defaultRuleThickness : defaultRuleThickness + onePixel;
// adjust numShift to maintain minClearance if needed
actualClearance =
(numShift - bmNum.descent) - (axisHeight + actualRuleThickness/2);
if (actualClearance < minClearance) {
numShift += (minClearance - actualClearance);
nscoord minClearanceNum = displayStyle ?
3 * defaultRuleThickness : defaultRuleThickness + onePixel;
nscoord minClearanceDen = minClearanceNum;
if (mathFont) {
minClearanceNum = mathFont->
GetMathConstant(displayStyle ?
gfxFontEntry::FractionNumDisplayStyleGapMin :
gfxFontEntry::FractionNumeratorGapMin,
oneDevPixel);
minClearanceDen = mathFont->
GetMathConstant(displayStyle ?
gfxFontEntry::FractionDenomDisplayStyleGapMin :
gfxFontEntry::FractionDenominatorGapMin,
oneDevPixel);
}
// adjust denShift to maintain minClearance if needed
actualClearance =
// adjust numShift to maintain minClearanceNum if needed
nscoord actualClearanceNum =
(numShift - bmNum.descent) - (axisHeight + actualRuleThickness/2);
if (actualClearanceNum < minClearanceNum) {
numShift += (minClearanceNum - actualClearanceNum);
}
// adjust denShift to maintain minClearanceDen if needed
nscoord actualClearanceDen =
(axisHeight - actualRuleThickness/2) - (bmDen.ascent - denShift);
if (actualClearance < minClearance) {
denShift += (minClearance - actualClearance);
if (actualClearanceDen < minClearanceDen) {
denShift += (minClearanceDen - actualClearanceDen);
}
}