mirror of
https://github.com/mozilla/gecko-dev.git
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395 lines
15 KiB
C++
395 lines
15 KiB
C++
/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
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/* vim: set ts=8 sts=2 et sw=2 tw=80: */
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/* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
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#include "nsMathMLmrootFrame.h"
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#include "mozilla/PresShell.h"
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#include "nsLayoutUtils.h"
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#include "nsPresContext.h"
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#include <algorithm>
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#include "gfxContext.h"
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#include "gfxMathTable.h"
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using namespace mozilla;
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//
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// <mroot> -- form a radical - implementation
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//
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static const char16_t kSqrChar = char16_t(0x221A);
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nsIFrame* NS_NewMathMLmrootFrame(PresShell* aPresShell, ComputedStyle* aStyle) {
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return new (aPresShell)
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nsMathMLmrootFrame(aStyle, aPresShell->GetPresContext());
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}
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NS_IMPL_FRAMEARENA_HELPERS(nsMathMLmrootFrame)
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nsMathMLmrootFrame::nsMathMLmrootFrame(ComputedStyle* aStyle,
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nsPresContext* aPresContext)
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: nsMathMLContainerFrame(aStyle, aPresContext, kClassID) {}
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nsMathMLmrootFrame::~nsMathMLmrootFrame() = default;
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void nsMathMLmrootFrame::Init(nsIContent* aContent, nsContainerFrame* aParent,
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nsIFrame* aPrevInFlow) {
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nsMathMLContainerFrame::Init(aContent, aParent, aPrevInFlow);
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nsAutoString sqrChar;
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sqrChar.Assign(kSqrChar);
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mSqrChar.SetData(sqrChar);
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mSqrChar.SetComputedStyle(Style());
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}
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bool nsMathMLmrootFrame::ShouldUseRowFallback() {
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bool isRootWithIndex = GetContent()->IsMathMLElement(nsGkAtoms::mroot);
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if (!isRootWithIndex) {
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return false;
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}
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// An mroot element expects exactly two children.
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nsIFrame* baseFrame = mFrames.FirstChild();
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if (!baseFrame) {
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return true;
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}
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nsIFrame* indexFrame = baseFrame->GetNextSibling();
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return !indexFrame || indexFrame->GetNextSibling();
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}
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bool nsMathMLmrootFrame::IsMrowLike() {
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bool isRootWithIndex = GetContent()->IsMathMLElement(nsGkAtoms::mroot);
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if (isRootWithIndex) {
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return false;
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}
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return mFrames.FirstChild() != mFrames.LastChild() || !mFrames.FirstChild();
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}
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NS_IMETHODIMP
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nsMathMLmrootFrame::InheritAutomaticData(nsIFrame* aParent) {
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nsMathMLContainerFrame::InheritAutomaticData(aParent);
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bool isRootWithIndex = GetContent()->IsMathMLElement(nsGkAtoms::mroot);
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if (!isRootWithIndex) {
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mPresentationData.flags |= NS_MATHML_STRETCH_ALL_CHILDREN_VERTICALLY;
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}
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return NS_OK;
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}
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NS_IMETHODIMP
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nsMathMLmrootFrame::TransmitAutomaticData() {
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bool isRootWithIndex = GetContent()->IsMathMLElement(nsGkAtoms::mroot);
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if (isRootWithIndex) {
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// 1. The REC says:
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// The <mroot> element increments scriptlevel by 2, and sets displaystyle
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// to "false", within index, but leaves both attributes unchanged within
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// base.
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// 2. The TeXbook (Ch 17. p.141) says \sqrt is compressed
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UpdatePresentationDataFromChildAt(1, 1, NS_MATHML_COMPRESSED,
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NS_MATHML_COMPRESSED);
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UpdatePresentationDataFromChildAt(0, 0, NS_MATHML_COMPRESSED,
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NS_MATHML_COMPRESSED);
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PropagateFrameFlagFor(mFrames.LastChild(),
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NS_FRAME_MATHML_SCRIPT_DESCENDANT);
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} else {
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// The TeXBook (Ch 17. p.141) says that \sqrt is cramped
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UpdatePresentationDataFromChildAt(0, -1, NS_MATHML_COMPRESSED,
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NS_MATHML_COMPRESSED);
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}
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return NS_OK;
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}
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void nsMathMLmrootFrame::BuildDisplayList(nsDisplayListBuilder* aBuilder,
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const nsDisplayListSet& aLists) {
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/////////////
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// paint the content we are square-rooting
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nsMathMLContainerFrame::BuildDisplayList(aBuilder, aLists);
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if (ShouldUseRowFallback()) {
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return;
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}
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/////////////
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// paint the sqrt symbol
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mSqrChar.Display(aBuilder, this, aLists, 0);
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DisplayBar(aBuilder, this, mBarRect, aLists);
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}
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void nsMathMLmrootFrame::GetRadicalXOffsets(nscoord aIndexWidth,
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nscoord aSqrWidth,
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nsFontMetrics* aFontMetrics,
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nscoord* aIndexOffset,
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nscoord* aSqrOffset) {
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// The index is tucked in closer to the radical while making sure
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// that the kern does not make the index and radical collide
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nscoord dxIndex, dxSqr, radicalKernBeforeDegree, radicalKernAfterDegree;
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nscoord oneDevPixel = aFontMetrics->AppUnitsPerDevPixel();
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RefPtr<gfxFont> mathFont =
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aFontMetrics->GetThebesFontGroup()->GetFirstMathFont();
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if (mathFont) {
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radicalKernBeforeDegree = mathFont->MathTable()->Constant(
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gfxMathTable::RadicalKernBeforeDegree, oneDevPixel);
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radicalKernAfterDegree = mathFont->MathTable()->Constant(
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gfxMathTable::RadicalKernAfterDegree, oneDevPixel);
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} else {
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nscoord em;
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GetEmHeight(aFontMetrics, em);
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radicalKernBeforeDegree = NSToCoordRound(5.0f * em / 18);
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radicalKernAfterDegree = NSToCoordRound(-10.0f * em / 18);
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}
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// Clamp radical kern degrees according to spec:
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// https://w3c.github.io/mathml-core/#root-with-index
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radicalKernBeforeDegree = std::max(0, radicalKernBeforeDegree);
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radicalKernAfterDegree = std::max(-aIndexWidth, radicalKernAfterDegree);
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dxIndex = radicalKernBeforeDegree;
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dxSqr = radicalKernBeforeDegree + aIndexWidth + radicalKernAfterDegree;
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if (aIndexOffset) {
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*aIndexOffset = dxIndex;
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}
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if (aSqrOffset) {
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*aSqrOffset = dxSqr;
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}
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}
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nsresult nsMathMLmrootFrame::Place(DrawTarget* aDrawTarget,
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const PlaceFlags& aFlags,
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ReflowOutput& aDesiredSize) {
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if (ShouldUseRowFallback()) {
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// report an error, encourage people to get their markups in order
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if (!aFlags.contains(PlaceFlag::MeasureOnly)) {
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ReportChildCountError();
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}
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return PlaceAsMrow(aDrawTarget, aFlags, aDesiredSize);
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}
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const bool isRootWithIndex = GetContent()->IsMathMLElement(nsGkAtoms::mroot);
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nsBoundingMetrics bmSqr, bmBase, bmIndex;
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nsIFrame *baseFrame = nullptr, *indexFrame = nullptr;
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nsMargin baseMargin, indexMargin;
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ReflowOutput baseSize(aDesiredSize.GetWritingMode());
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ReflowOutput indexSize(aDesiredSize.GetWritingMode());
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if (isRootWithIndex) {
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baseFrame = mFrames.FirstChild();
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indexFrame = baseFrame->GetNextSibling();
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baseMargin = GetMarginForPlace(aFlags, baseFrame);
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indexMargin = GetMarginForPlace(aFlags, indexFrame);
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GetReflowAndBoundingMetricsFor(baseFrame, baseSize, bmBase);
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GetReflowAndBoundingMetricsFor(indexFrame, indexSize, bmIndex);
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} else {
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// Format our content as an mrow without border/padding to obtain the
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// square root base. The metrics/frame for the index are ignored.
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PlaceFlags flags = aFlags + PlaceFlag::MeasureOnly +
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PlaceFlag::IgnoreBorderPadding +
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PlaceFlag::DoNotAdjustForWidthAndHeight;
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nsresult rv = nsMathMLContainerFrame::Place(aDrawTarget, flags, baseSize);
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if (NS_FAILED(rv)) {
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DidReflowChildren(PrincipalChildList().FirstChild());
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return rv;
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}
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bmBase = baseSize.mBoundingMetrics;
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}
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////////////
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// Prepare the radical symbol and the overline bar
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float fontSizeInflation = nsLayoutUtils::FontSizeInflationFor(this);
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RefPtr<nsFontMetrics> fm =
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nsLayoutUtils::GetFontMetricsForFrame(this, fontSizeInflation);
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nscoord ruleThickness, leading, psi;
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GetRadicalParameters(fm, StyleFont()->mMathStyle == StyleMathStyle::Normal,
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ruleThickness, leading, psi);
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// built-in: adjust clearance psi to emulate \mathstrut using '1' (TexBook,
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// p.131)
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char16_t one = '1';
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nsBoundingMetrics bmOne =
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nsLayoutUtils::AppUnitBoundsOfString(&one, 1, *fm, aDrawTarget);
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if (bmOne.ascent > bmBase.ascent + baseMargin.top) {
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psi += bmOne.ascent - bmBase.ascent - baseMargin.top;
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}
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// make sure that the rule appears on on screen
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nscoord onePixel = nsPresContext::CSSPixelsToAppUnits(1);
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if (ruleThickness < onePixel) {
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ruleThickness = onePixel;
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}
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// adjust clearance psi to get an exact number of pixels -- this
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// gives a nicer & uniform look on stacked radicals (bug 130282)
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nscoord delta = psi % onePixel;
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if (delta) {
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psi += onePixel - delta; // round up
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}
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// Stretch the radical symbol to the appropriate height if it is not big
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// enough.
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nsBoundingMetrics contSize = bmBase;
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contSize.descent =
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bmBase.ascent + bmBase.descent + baseMargin.TopBottom() + psi;
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contSize.ascent = ruleThickness;
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// height(radical) should be >= height(base) + psi + ruleThickness
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nsBoundingMetrics radicalSize;
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if (aFlags.contains(PlaceFlag::IntrinsicSize)) {
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nscoord radical_width =
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mSqrChar.GetMaxWidth(this, aDrawTarget, fontSizeInflation);
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bmSqr.leftBearing = 0;
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bmSqr.rightBearing = radical_width;
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bmSqr.width = radical_width;
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bmSqr.ascent = bmSqr.descent = 0;
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} else {
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mSqrChar.Stretch(this, aDrawTarget, fontSizeInflation,
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NS_STRETCH_DIRECTION_VERTICAL, contSize, radicalSize,
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NS_STRETCH_LARGER,
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StyleVisibility()->mDirection == StyleDirection::Rtl);
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// radicalSize have changed at this point, and should match with
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// the bounding metrics of the char
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mSqrChar.GetBoundingMetrics(bmSqr);
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}
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// Update the desired size for the container (like msqrt, index is not yet
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// included) the baseline will be that of the base.
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mBoundingMetrics.ascent =
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bmBase.ascent + baseMargin.top + psi + ruleThickness;
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mBoundingMetrics.descent =
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std::max(bmBase.descent + baseMargin.bottom,
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(bmSqr.ascent + bmSqr.descent - mBoundingMetrics.ascent));
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mBoundingMetrics.width = bmSqr.width + bmBase.width + baseMargin.LeftRight();
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mBoundingMetrics.leftBearing = bmSqr.leftBearing;
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mBoundingMetrics.rightBearing =
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bmSqr.width +
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std::max(
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bmBase.width + baseMargin.LeftRight(),
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bmBase.rightBearing + baseMargin.left); // take also care of the rule
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aDesiredSize.SetBlockStartAscent(mBoundingMetrics.ascent + leading);
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aDesiredSize.Height() =
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aDesiredSize.BlockStartAscent() +
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std::max(baseSize.Height() - baseSize.BlockStartAscent(),
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mBoundingMetrics.descent + ruleThickness);
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aDesiredSize.Width() = mBoundingMetrics.width;
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nscoord indexClearance = 0, dxIndex = 0, dxSqr = 0, indexRaisedAscent = 0;
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if (isRootWithIndex) {
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/////////////
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// Re-adjust the desired size to include the index.
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// the index is raised by some fraction of the height
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// of the radical, see \mroot macro in App. B, TexBook
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float raiseIndexPercent = 0.6f;
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RefPtr<gfxFont> mathFont = fm->GetThebesFontGroup()->GetFirstMathFont();
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if (mathFont) {
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raiseIndexPercent = mathFont->MathTable()->Constant(
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gfxMathTable::RadicalDegreeBottomRaisePercent);
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}
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nscoord raiseIndexDelta =
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NSToCoordRound(raiseIndexPercent * (bmSqr.ascent + bmSqr.descent));
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indexRaisedAscent = mBoundingMetrics.ascent // top of radical
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-
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(bmSqr.ascent + bmSqr.descent) // to bottom of radical
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+ raiseIndexDelta + bmIndex.ascent + bmIndex.descent +
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indexMargin.TopBottom(); // to top of raised index
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if (mBoundingMetrics.ascent < indexRaisedAscent) {
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indexClearance =
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indexRaisedAscent -
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mBoundingMetrics.ascent; // excess gap introduced by a tall index
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mBoundingMetrics.ascent = indexRaisedAscent;
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nscoord descent = aDesiredSize.Height() - aDesiredSize.BlockStartAscent();
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aDesiredSize.SetBlockStartAscent(mBoundingMetrics.ascent + leading);
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aDesiredSize.Height() = aDesiredSize.BlockStartAscent() + descent;
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}
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GetRadicalXOffsets(bmIndex.width + indexMargin.LeftRight(), bmSqr.width, fm,
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&dxIndex, &dxSqr);
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mBoundingMetrics.width =
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dxSqr + bmSqr.width + bmBase.width + baseMargin.LeftRight();
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mBoundingMetrics.leftBearing =
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std::min(dxIndex + bmIndex.leftBearing, dxSqr + bmSqr.leftBearing);
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mBoundingMetrics.rightBearing =
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dxSqr + bmSqr.width +
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std::max(bmBase.width + baseMargin.LeftRight(),
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bmBase.rightBearing + baseMargin.left);
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aDesiredSize.Width() = mBoundingMetrics.width;
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}
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aDesiredSize.mBoundingMetrics = mBoundingMetrics;
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// Apply width/height to math content box.
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const PlaceFlags flags;
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auto sizes = GetWidthAndHeightForPlaceAdjustment(flags);
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nscoord shiftX = ApplyAdjustmentForWidthAndHeight(flags, sizes, aDesiredSize,
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mBoundingMetrics);
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// Add padding+border around the final layout.
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auto borderPadding = GetBorderPaddingForPlace(aFlags);
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InflateReflowAndBoundingMetrics(borderPadding, aDesiredSize,
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mBoundingMetrics);
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if (!aFlags.contains(PlaceFlag::MeasureOnly)) {
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nsPresContext* presContext = PresContext();
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const bool isRTL = StyleVisibility()->mDirection == StyleDirection::Rtl;
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nscoord borderPaddingInlineStart =
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isRTL ? borderPadding.right : borderPadding.left;
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nscoord dx, dy;
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if (isRootWithIndex) {
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// place the index
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dx = borderPaddingInlineStart + dxIndex +
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indexMargin.Side(isRTL ? eSideRight : eSideLeft);
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dy = aDesiredSize.BlockStartAscent() -
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(indexRaisedAscent + indexSize.BlockStartAscent() - bmIndex.ascent);
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FinishReflowChild(
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indexFrame, presContext, indexSize, nullptr,
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MirrorIfRTL(aDesiredSize.Width(), indexSize.Width(), dx),
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dy + indexMargin.top, ReflowChildFlags::Default);
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}
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// place the radical symbol and the radical bar
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dx = borderPaddingInlineStart + dxSqr;
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dy = borderPadding.top + indexClearance +
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leading; // leave a leading at the top
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mSqrChar.SetRect(nsRect(MirrorIfRTL(aDesiredSize.Width(), bmSqr.width, dx),
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dy, bmSqr.width, bmSqr.ascent + bmSqr.descent));
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dx += bmSqr.width;
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mBarRect.SetRect(MirrorIfRTL(aDesiredSize.Width(),
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bmBase.width + baseMargin.LeftRight(), dx),
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dy, bmBase.width + baseMargin.LeftRight(), ruleThickness);
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// place the base
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if (isRootWithIndex) {
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dx += isRTL ? baseMargin.right : baseMargin.left;
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dy = aDesiredSize.BlockStartAscent() - baseSize.BlockStartAscent();
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FinishReflowChild(baseFrame, presContext, baseSize, nullptr,
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MirrorIfRTL(aDesiredSize.Width(), baseSize.Width(), dx),
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dy, ReflowChildFlags::Default);
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} else {
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nscoord dx_left = borderPadding.left + shiftX;
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if (!isRTL) {
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dx_left += bmSqr.width;
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}
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PositionRowChildFrames(dx_left, aDesiredSize.BlockStartAscent());
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}
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}
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mReference.x = 0;
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mReference.y = aDesiredSize.BlockStartAscent();
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return NS_OK;
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}
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void nsMathMLmrootFrame::DidSetComputedStyle(ComputedStyle* aOldStyle) {
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nsMathMLContainerFrame::DidSetComputedStyle(aOldStyle);
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mSqrChar.SetComputedStyle(Style());
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}
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