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 = nsnull; 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 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 = NS_MAX(onePixel, coreData.leftSpace); nscoord rightSpace = NS_MAX(onePixel, coreData.rightSpace); ////////////////// // 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 = NS_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 = NS_MAX(dxNum + bmNum.rightBearing, dxDen + bmDen.rightBearing); if (mBoundingMetrics.rightBearing < width - rightSpace) mBoundingMetrics.rightBearing = width - rightSpace; mBoundingMetrics.leftBearing = NS_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, nsnull, sizeNum, dxNum, dy, 0); // place denominator dy = aDesiredSize.height - sizeDen.height; FinishReflowChild(frameDen, presContext, nsnull, 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 * NS_MIN(2 * mLineThickness, slashMaxWidthConstant); nscoord leftSpace = NS_MAX(padding, coreData.leftSpace); nscoord rightSpace = NS_MAX(padding, coreData.rightSpace); 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 = NS_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 = NS_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 + NS_MIN(slashMaxWidthConstant, (mBoundingMetrics.ascent + mBoundingMetrics.descent) / slashRatio); } // Set horizontal bounding metrics mBoundingMetrics.leftBearing = leftSpace + bmNum.leftBearing; mBoundingMetrics.rightBearing = leftSpace + bmNum.width + mLineRect.width + bmDen.rightBearing; mBoundingMetrics.width = leftSpace + bmNum.width + mLineRect.width + bmDen.width + rightSpace; // 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) { FinishReflowChild(frameNum, presContext, nsnull, sizeNum, leftSpace, aDesiredSize.ascent - numShift - sizeNum.ascent, 0); mLineRect.SetRect(leftSpace + bmNum.width, aDesiredSize.ascent - mBoundingMetrics.ascent, mLineRect.width, aDesiredSize.height - 2 * padding); FinishReflowChild(frameDen, presContext, nsnull, sizeDen, leftSpace + bmNum.width + mLineRect.width, aDesiredSize.ascent + denShift - sizeDen.ascent, 0); } } return NS_OK; }
/* virtual */ nsresult nsMathMLmfracFrame::Place(nsIRenderingContext& aRenderingContext, PRBool aPlaceOrigin, nsHTMLReflowMetrics& aDesiredSize) { //////////////////////////////////// // Get the children's desired sizes nsBoundingMetrics bmNum, bmDen; nsHTMLReflowMetrics sizeNum; nsHTMLReflowMetrics sizeDen; nsIFrame* frameDen = nsnull; 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 NS_WARNING("invalid markup"); return ReflowError(aRenderingContext, aDesiredSize); } GetReflowAndBoundingMetricsFor(frameNum, sizeNum, bmNum); GetReflowAndBoundingMetricsFor(frameDen, sizeDen, bmDen); ////////////////// // Get shifts nsPresContext* presContext = PresContext(); nscoord onePixel = nsPresContext::CSSPixelsToAppUnits(1); aRenderingContext.SetFont(GetStyleFont()->mFont, nsnull); nsCOMPtr<nsIFontMetrics> fm; aRenderingContext.GetFontMetrics(*getter_AddRefs(fm)); nscoord defaultRuleThickness, axisHeight; GetRuleThickness(aRenderingContext, fm, defaultRuleThickness); GetAxisHeight(aRenderingContext, fm, axisHeight); // 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) nsEmbellishData coreData; GetEmbellishDataFrom(mEmbellishData.coreFrame, coreData); nscoord leftSpace = PR_MAX(onePixel, coreData.leftSpace); nscoord rightSpace = PR_MAX(onePixel, coreData.rightSpace); // see if the linethickness attribute is there nsAutoString value; GetAttribute(mContent, mPresentationData.mstyle, nsGkAtoms::linethickness_, value); mLineRect.height = CalcLineThickness(presContext, mStyleContext, value, onePixel, defaultRuleThickness); 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 = mLineRect.height; 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 = PR_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 = PR_MAX(dxNum + bmNum.rightBearing, dxDen + bmDen.rightBearing); if (mBoundingMetrics.rightBearing < width - rightSpace) mBoundingMetrics.rightBearing = width - rightSpace; mBoundingMetrics.leftBearing = PR_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, nsnull, sizeNum, dxNum, dy, 0); // place denominator dy = aDesiredSize.height - sizeDen.height; FinishReflowChild(frameDen, presContext, nsnull, 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); } return NS_OK; }