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gecko-dev/layout/mathml/nsMathMLmrootFrame.cpp

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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 "nsMathMLmrootFrame.h"
#include "mozilla/PresShell.h"
#include "nsPresContext.h"
#include <algorithm>
#include "gfxContext.h"
#include "gfxMathTable.h"
using namespace mozilla;
//
// <mroot> -- form a radical - implementation
//
static const char16_t kSqrChar = char16_t(0x221A);
nsIFrame* NS_NewMathMLmrootFrame(PresShell* aPresShell, ComputedStyle* aStyle) {
return new (aPresShell)
nsMathMLmrootFrame(aStyle, aPresShell->GetPresContext());
}
NS_IMPL_FRAMEARENA_HELPERS(nsMathMLmrootFrame)
nsMathMLmrootFrame::nsMathMLmrootFrame(ComputedStyle* aStyle,
nsPresContext* aPresContext)
: nsMathMLContainerFrame(aStyle, aPresContext, kClassID),
mSqrChar(),
mBarRect() {}
nsMathMLmrootFrame::~nsMathMLmrootFrame() = default;
void nsMathMLmrootFrame::Init(nsIContent* aContent, nsContainerFrame* aParent,
nsIFrame* aPrevInFlow) {
nsMathMLContainerFrame::Init(aContent, aParent, aPrevInFlow);
nsAutoString sqrChar;
sqrChar.Assign(kSqrChar);
mSqrChar.SetData(sqrChar);
mSqrChar.SetComputedStyle(Style());
}
NS_IMETHODIMP
nsMathMLmrootFrame::TransmitAutomaticData() {
// 1. The REC says:
// The <mroot> element increments scriptlevel by 2, and sets displaystyle
// to "false", within index, but leaves both attributes unchanged within
// base.
// 2. The TeXbook (Ch 17. p.141) says \sqrt is compressed
UpdatePresentationDataFromChildAt(1, 1, NS_MATHML_COMPRESSED,
NS_MATHML_COMPRESSED);
UpdatePresentationDataFromChildAt(0, 0, NS_MATHML_COMPRESSED,
NS_MATHML_COMPRESSED);
PropagateFrameFlagFor(mFrames.LastChild(), NS_FRAME_MATHML_SCRIPT_DESCENDANT);
return NS_OK;
}
void nsMathMLmrootFrame::BuildDisplayList(nsDisplayListBuilder* aBuilder,
const nsDisplayListSet& aLists) {
/////////////
// paint the content we are square-rooting
nsMathMLContainerFrame::BuildDisplayList(aBuilder, aLists);
/////////////
// paint the sqrt symbol
if (!NS_MATHML_HAS_ERROR(mPresentationData.flags)) {
mSqrChar.Display(aBuilder, this, aLists, 0);
DisplayBar(aBuilder, this, mBarRect, aLists);
#if defined(DEBUG) && defined(SHOW_BOUNDING_BOX)
// for visual debug
nsRect rect;
mSqrChar.GetRect(rect);
nsBoundingMetrics bm;
mSqrChar.GetBoundingMetrics(bm);
DisplayBoundingMetrics(aBuilder, this, rect.TopLeft(), bm, aLists);
#endif
}
}
void nsMathMLmrootFrame::GetRadicalXOffsets(nscoord aIndexWidth,
nscoord aSqrWidth,
nsFontMetrics* aFontMetrics,
nscoord* aIndexOffset,
nscoord* aSqrOffset) {
// The index is tucked in closer to the radical while making sure
// that the kern does not make the index and radical collide
nscoord dxIndex, dxSqr;
nscoord xHeight = aFontMetrics->XHeight();
nscoord indexRadicalKern = NSToCoordRound(1.35f * xHeight);
nscoord oneDevPixel = aFontMetrics->AppUnitsPerDevPixel();
gfxFont* mathFont = aFontMetrics->GetThebesFontGroup()->GetFirstMathFont();
if (mathFont) {
indexRadicalKern = mathFont->MathTable()->Constant(
gfxMathTable::RadicalKernAfterDegree, oneDevPixel);
indexRadicalKern = -indexRadicalKern;
}
if (indexRadicalKern > aIndexWidth) {
dxIndex = indexRadicalKern - aIndexWidth;
dxSqr = 0;
} else {
dxIndex = 0;
dxSqr = aIndexWidth - indexRadicalKern;
}
if (mathFont) {
// add some kern before the radical index
nscoord indexRadicalKernBefore = 0;
indexRadicalKernBefore = mathFont->MathTable()->Constant(
gfxMathTable::RadicalKernBeforeDegree, oneDevPixel);
dxIndex += indexRadicalKernBefore;
dxSqr += indexRadicalKernBefore;
} else {
// avoid collision by leaving a minimum space between index and radical
nscoord minimumClearance = aSqrWidth / 2;
if (dxIndex + aIndexWidth + minimumClearance > dxSqr + aSqrWidth) {
if (aIndexWidth + minimumClearance < aSqrWidth) {
dxIndex = aSqrWidth - (aIndexWidth + minimumClearance);
dxSqr = 0;
} else {
dxIndex = 0;
dxSqr = (aIndexWidth + minimumClearance) - aSqrWidth;
}
}
}
if (aIndexOffset) *aIndexOffset = dxIndex;
if (aSqrOffset) *aSqrOffset = dxSqr;
}
void nsMathMLmrootFrame::Reflow(nsPresContext* aPresContext,
ReflowOutput& aDesiredSize,
const ReflowInput& aReflowInput,
nsReflowStatus& aStatus) {
MarkInReflow();
MOZ_ASSERT(aStatus.IsEmpty(), "Caller should pass a fresh reflow status!");
nsReflowStatus childStatus;
mPresentationData.flags &= ~NS_MATHML_ERROR;
aDesiredSize.ClearSize();
aDesiredSize.SetBlockStartAscent(0);
nsBoundingMetrics bmSqr, bmBase, bmIndex;
DrawTarget* drawTarget = aReflowInput.mRenderingContext->GetDrawTarget();
//////////////////
// Reflow Children
int32_t count = 0;
nsIFrame* baseFrame = nullptr;
nsIFrame* indexFrame = nullptr;
ReflowOutput baseSize(aReflowInput);
ReflowOutput indexSize(aReflowInput);
nsIFrame* childFrame = mFrames.FirstChild();
while (childFrame) {
// ask our children to compute their bounding metrics
ReflowOutput childDesiredSize(aReflowInput);
WritingMode wm = childFrame->GetWritingMode();
LogicalSize availSize = aReflowInput.ComputedSize(wm);
availSize.BSize(wm) = NS_UNCONSTRAINEDSIZE;
ReflowInput childReflowInput(aPresContext, aReflowInput, childFrame,
availSize);
ReflowChild(childFrame, aPresContext, childDesiredSize, childReflowInput,
childStatus);
// NS_ASSERTION(childStatus.IsComplete(), "bad status");
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();
ReflowError(drawTarget, aDesiredSize);
NS_FRAME_SET_TRUNCATION(aStatus, aReflowInput, aDesiredSize);
// Call DidReflow() for the child frames we successfully did reflow.
DidReflowChildren(mFrames.FirstChild(), childFrame);
return;
}
////////////
// Prepare the radical symbol and the overline bar
float fontSizeInflation = nsLayoutUtils::FontSizeInflationFor(this);
RefPtr<nsFontMetrics> fm =
nsLayoutUtils::GetFontMetricsForFrame(this, fontSizeInflation);
nscoord ruleThickness, leading, psi;
GetRadicalParameters(fm,
StyleFont()->mMathStyle == NS_STYLE_MATH_STYLE_NORMAL,
ruleThickness, leading, psi);
// built-in: adjust clearance psi to emulate \mathstrut using '1' (TexBook,
// p.131)
char16_t one = '1';
nsBoundingMetrics bmOne =
nsLayoutUtils::AppUnitBoundsOfString(&one, 1, *fm, drawTarget);
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(this, drawTarget, fontSizeInflation,
NS_STRETCH_DIRECTION_VERTICAL, contSize, radicalSize,
NS_STRETCH_LARGER,
StyleVisibility()->mDirection == StyleDirection::Rtl);
// 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.SetBlockStartAscent(mBoundingMetrics.ascent + leading);
aDesiredSize.Height() =
aDesiredSize.BlockStartAscent() +
std::max(baseSize.Height() - baseSize.BlockStartAscent(),
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
float raiseIndexPercent = 0.6f;
gfxFont* mathFont = fm->GetThebesFontGroup()->GetFirstMathFont();
if (mathFont) {
raiseIndexPercent = mathFont->MathTable()->Constant(
gfxMathTable::RadicalDegreeBottomRaisePercent);
}
nscoord raiseIndexDelta =
NSToCoordRound(raiseIndexPercent * (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.BlockStartAscent();
aDesiredSize.SetBlockStartAscent(mBoundingMetrics.ascent + leading);
aDesiredSize.Height() = aDesiredSize.BlockStartAscent() + 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.BlockStartAscent() -
(indexRaisedAscent + indexSize.BlockStartAscent() - bmIndex.ascent);
FinishReflowChild(indexFrame, aPresContext, indexSize, nullptr,
MirrorIfRTL(aDesiredSize.Width(), indexSize.Width(), dx),
dy, ReflowChildFlags::Default);
// 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.BlockStartAscent() - baseSize.BlockStartAscent();
FinishReflowChild(baseFrame, aPresContext, baseSize, nullptr,
MirrorIfRTL(aDesiredSize.Width(), baseSize.Width(), dx), dy,
ReflowChildFlags::Default);
mReference.x = 0;
mReference.y = aDesiredSize.BlockStartAscent();
NS_FRAME_SET_TRUNCATION(aStatus, aReflowInput, aDesiredSize);
}
/* virtual */
void nsMathMLmrootFrame::GetIntrinsicISizeMetrics(gfxContext* aRenderingContext,
ReflowOutput& aDesiredSize) {
nsIFrame* baseFrame = mFrames.FirstChild();
nsIFrame* indexFrame = nullptr;
if (baseFrame) indexFrame = baseFrame->GetNextSibling();
if (!indexFrame || indexFrame->GetNextSibling()) {
ReflowError(aRenderingContext->GetDrawTarget(), aDesiredSize);
return;
}
float fontSizeInflation = nsLayoutUtils::FontSizeInflationFor(this);
nscoord baseWidth = nsLayoutUtils::IntrinsicForContainer(
aRenderingContext, baseFrame, IntrinsicISizeType::PrefISize);
nscoord indexWidth = nsLayoutUtils::IntrinsicForContainer(
aRenderingContext, indexFrame, IntrinsicISizeType::PrefISize);
nscoord sqrWidth = mSqrChar.GetMaxWidth(
this, aRenderingContext->GetDrawTarget(), fontSizeInflation);
nscoord dxSqr;
RefPtr<nsFontMetrics> fm =
nsLayoutUtils::GetFontMetricsForFrame(this, fontSizeInflation);
GetRadicalXOffsets(indexWidth, sqrWidth, fm, nullptr, &dxSqr);
nscoord width = dxSqr + sqrWidth + baseWidth;
aDesiredSize.Width() = width;
aDesiredSize.mBoundingMetrics.width = width;
aDesiredSize.mBoundingMetrics.leftBearing = 0;
aDesiredSize.mBoundingMetrics.rightBearing = width;
}
void nsMathMLmrootFrame::DidSetComputedStyle(ComputedStyle* aOldStyle) {
nsMathMLContainerFrame::DidSetComputedStyle(aOldStyle);
mSqrChar.SetComputedStyle(Style());
}
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