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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 */
* structs that contain the data provided by ComputedStyle, the
* internal API for computed style data for an element
#ifndef nsStyleStruct_h___
#define nsStyleStruct_h___
#include "mozilla/Assertions.h"
#include "mozilla/Attributes.h"
#include "mozilla/Likely.h"
#include "mozilla/Maybe.h"
#include "mozilla/UniquePtr.h"
#include "mozilla/WindowButtonType.h"
#include "nsColor.h"
#include "nsCoord.h"
#include "nsMargin.h"
#include "nsFont.h"
#include "nsStyleAutoArray.h"
#include "nsStyleConsts.h"
#include "nsChangeHint.h"
#include "nsTArray.h"
#include "imgIContainer.h"
#include "imgRequestProxy.h"
#include "CounterStyleManager.h"
#include <cstddef> // offsetof()
#include "X11UndefineNone.h"
class nsIFrame;
class nsIURI;
class nsTextFrame;
struct nsStyleDisplay;
struct nsStyleVisibility;
namespace mozilla {
class ComputedStyle;
struct IntrinsicSize;
} // namespace mozilla
namespace mozilla::dom {
enum class CompositeOperation : uint8_t;
} // namespace mozilla::dom
namespace mozilla {
using Position = StylePosition;
template <>
inline bool StylePosition::HasPercent() const {
return horizontal.HasPercent() || vertical.HasPercent();
* True if the effective background image position described by this depends on
* the size of the corresponding frame.
template <>
inline bool StylePosition::DependsOnPositioningAreaSize() const {
return HasPercent();
template <>
inline Position Position::FromPercentage(float aPercent) {
return {LengthPercentage::FromPercentage(aPercent),
* Convenience struct for querying if a given box has size-containment in
* either axis.
struct ContainSizeAxes {
ContainSizeAxes(bool aIContained, bool aBContained)
: mIContained(aIContained), mBContained(aBContained) {}
bool IsBoth() const { return mIContained && mBContained; }
bool IsAny() const { return mIContained || mBContained; }
bool operator==(const ContainSizeAxes& aOther) const {
return mIContained == aOther.mIContained &&
mBContained == aOther.mBContained;
* Return a contained size from an uncontained size.
nsSize ContainSize(const nsSize& aUncontainedSize,
const nsIFrame& aFrame) const;
IntrinsicSize ContainIntrinsicSize(const IntrinsicSize& aUncontainedSize,
const nsIFrame& aFrame) const;
Maybe<nscoord> ContainIntrinsicBSize(const nsIFrame& aFrame,
nscoord aNoneValue = 0) const;
Maybe<nscoord> ContainIntrinsicISize(const nsIFrame& aFrame,
nscoord aNoneValue = 0) const;
const bool mIContained;
const bool mBContained;
} // namespace mozilla
#define STYLE_STRUCT(name_) \
name_(const name_&); \
void MarkLeaked() const { MOZ_COUNT_DTOR(name_); } \
nsChangeHint CalcDifference(const name_&) const;
explicit nsStyleFont(const mozilla::dom::Document&);
* Return a given size multiplied by the current text zoom factor (in
* aPresContext).
* The size is allowed to be negative, but the caller is expected to deal with
* negative results.
static mozilla::Length ZoomText(const mozilla::dom::Document&,
nsAtom* GetFontPaletteAtom() const { return mFontPalette._0.AsAtom(); }
nsFont mFont;
// Our "computed size". Can be different from mFont.size which is our "actual
// size" and is enforced to be >= the user's preferred min-size. mFont.size
// should be used for display purposes while mSize is the value to return in
// getComputedStyle() for example.
mozilla::NonNegativeLength mSize;
// In stylo these three track whether the size is keyword-derived
// and if so if it has been modified by a factor/offset
float mFontSizeFactor;
mozilla::Length mFontSizeOffset;
mozilla::StyleFontSizeKeyword mFontSizeKeyword;
mozilla::StyleFontPalette mFontPalette;
// math-depth support (used for MathML scriptlevel)
int8_t mMathDepth;
mozilla::StyleLineHeight mLineHeight;
// allow different min font-size for certain cases
mozilla::StylePercentage mMinFontSizeRatio{1.0f};
// MathML mathvariant support
mozilla::StyleMathVariant mMathVariant;
// math-style support (used for MathML displaystyle)
mozilla::StyleMathStyle mMathStyle;
// Was mLanguage set based on a lang attribute in the document?
bool mExplicitLanguage = false;
mozilla::StyleXTextScale mXTextScale;
bool MinFontSizeEnabled() const {
return mXTextScale == mozilla::StyleXTextScale::All;
// The value mSize would have had if scriptminsize had never been applied
mozilla::NonNegativeLength mScriptUnconstrainedSize;
mozilla::Length mScriptMinSize;
RefPtr<nsAtom> mLanguage;
struct nsStyleImageLayers {
enum class LayerType : uint8_t { Background = 0, Mask };
explicit nsStyleImageLayers(LayerType aType);
nsStyleImageLayers(const nsStyleImageLayers& aSource);
struct Repeat {
mozilla::StyleImageLayerRepeat mXRepeat =
mozilla::StyleImageLayerRepeat mYRepeat =
// Initialize nothing
Repeat() = default;
bool IsInitialValue() const {
return mXRepeat == mozilla::StyleImageLayerRepeat::Repeat &&
mYRepeat == mozilla::StyleImageLayerRepeat::Repeat;
bool DependsOnPositioningAreaSize() const {
return mXRepeat == mozilla::StyleImageLayerRepeat::Space ||
mYRepeat == mozilla::StyleImageLayerRepeat::Space;
bool operator==(const Repeat& aOther) const {
return mXRepeat == aOther.mXRepeat && mYRepeat == aOther.mYRepeat;
bool operator!=(const Repeat& aOther) const { return !(*this == aOther); }
struct Layer {
using StyleGeometryBox = mozilla::StyleGeometryBox;
using StyleImageLayerAttachment = mozilla::StyleImageLayerAttachment;
using StyleBackgroundSize = mozilla::StyleBackgroundSize;
mozilla::StyleImage mImage;
mozilla::Position mPosition;
StyleBackgroundSize mSize;
StyleGeometryBox mClip;
MOZ_INIT_OUTSIDE_CTOR StyleGeometryBox mOrigin;
// This property is used for background layer only.
// For a mask layer, it should always be the initial value, which is
// StyleImageLayerAttachment::Scroll.
StyleImageLayerAttachment mAttachment;
// This property is used for background layer only.
// For a mask layer, it should always be the initial value, which is
// StyleBlend::Normal.
mozilla::StyleBlend mBlendMode;
// This property is used for mask layer only.
// For a background layer, it should always be the initial value, which is
// StyleMaskComposite::Add.
mozilla::StyleMaskComposite mComposite;
// mask-only property. This property is used for mask layer only. For a
// background layer, it should always be the initial value, which is
// StyleMaskMode::MatchSource.
mozilla::StyleMaskMode mMaskMode;
Repeat mRepeat;
// This constructor does not initialize mRepeat or mOrigin and Initialize()
// must be called to do that.
// Initialize mRepeat and mOrigin by specified layer type
void Initialize(LayerType aType);
void ResolveImage(mozilla::dom::Document& aDocument,
const Layer* aOldLayer) {
mImage.ResolveImage(aDocument, aOldLayer ? &aOldLayer->mImage : nullptr);
// True if the rendering of this layer might change when the size
// of the background positioning area changes. This is true for any
// non-solid-color background whose position or size depends on
// the size of the positioning area. It's also true for SVG images
// whose root <svg> node has a viewBox.
bool RenderingMightDependOnPositioningAreaSizeChange() const;
// Compute the change hint required by changes in just this layer.
nsChangeHint CalcDifference(const Layer& aNewLayer) const;
// An equality operator that compares the images using URL-equality
// rather than pointer-equality.
bool operator==(const Layer& aOther) const;
bool operator!=(const Layer& aOther) const { return !(*this == aOther); }
// The (positive) number of computed values of each property, since
// the lengths of the lists are independent.
uint32_t mAttachmentCount;
uint32_t mClipCount;
uint32_t mOriginCount;
uint32_t mRepeatCount;
uint32_t mPositionXCount;
uint32_t mPositionYCount;
uint32_t mImageCount;
uint32_t mSizeCount;
uint32_t mMaskModeCount;
uint32_t mBlendModeCount;
uint32_t mCompositeCount;
// Layers are stored in an array, matching the top-to-bottom order in
// which they are specified in CSS. The number of layers to be used
// should come from the background-image property. We create
// additional |Layer| objects for *any* property, not just
// background-image. This means that the bottommost layer that
// callers in layout care about (which is also the one whose
// background-clip applies to the background-color) may not be last
// layer. In layers below the bottom layer, properties will be
// uninitialized unless their count, above, indicates that they are
// present.
nsStyleAutoArray<Layer> mLayers;
const Layer& BottomLayer() const { return mLayers[mImageCount - 1]; }
void ResolveImages(mozilla::dom::Document& aDocument,
const nsStyleImageLayers* aOldLayers) {
for (uint32_t i = 0; i < mImageCount; ++i) {
const Layer* oldLayer = (aOldLayers && aOldLayers->mLayers.Length() > i)
? &aOldLayers->mLayers[i]
: nullptr;
mLayers[i].ResolveImage(aDocument, oldLayer);
// Fill unspecified layers by cycling through their values
// till they all are of length aMaxItemCount
void FillAllLayers(uint32_t aMaxItemCount);
nsChangeHint CalcDifference(const nsStyleImageLayers& aNewLayers,
nsStyleImageLayers::LayerType aType) const;
nsStyleImageLayers& operator=(const nsStyleImageLayers& aOther);
nsStyleImageLayers& operator=(nsStyleImageLayers&& aOther) = default;
bool operator==(const nsStyleImageLayers& aOther) const;
static const nsCSSPropertyID kBackgroundLayerTable[];
static const nsCSSPropertyID kMaskLayerTable[];
for (uint32_t var_ = (layers_).mImageCount; (var_)-- != 0;)
start_, count_) \
(int32_t)(start_) >= 0 && (uint32_t)(start_) < (layers_).mImageCount, \
"Invalid layer start!"); \
NS_ASSERTION((count_) > 0 && (count_) <= (start_) + 1, \
"Invalid layer range!"); \
for (uint32_t var_ = (start_) + 1; \
(var_)-- != (uint32_t)((start_) + 1 - (count_));)
struct MOZ_NEEDS_MEMMOVABLE_MEMBERS nsStyleBackground {
void TriggerImageLoads(mozilla::dom::Document&, const nsStyleBackground*);
// Return the background color as nscolor.
nscolor BackgroundColor(const nsIFrame* aFrame) const;
nscolor BackgroundColor(const mozilla::ComputedStyle* aStyle) const;
// True if this background is completely transparent.
bool IsTransparent(const nsIFrame* aFrame) const;
bool IsTransparent(const mozilla::ComputedStyle* aStyle) const;
// We have to take slower codepaths for fixed background attachment,
// but we don't want to do that when there's no image.
// Not inline because it uses an nsCOMPtr<imgIRequest>
// FIXME: Should be in nsStyleStructInlines.h.
bool HasFixedBackground(nsIFrame* aFrame) const;
// Checks to see if this has a non-empty image with "local" attachment.
// This is defined in nsStyleStructInlines.h.
inline bool HasLocalBackground() const;
const nsStyleImageLayers::Layer& BottomLayer() const {
return mImage.BottomLayer();
nsStyleImageLayers mImage;
mozilla::StyleColor mBackgroundColor;
bool GetMargin(nsMargin& aMargin) const {
bool convertsToLength = mMargin.All(
[](const auto& aLength) { return aLength.ConvertsToLength(); });
if (!convertsToLength) {
return false;
for (const auto side : mozilla::AllPhysicalSides()) {
aMargin.Side(side) = mMargin.Get(side).AsLengthPercentage().ToLength();
return true;
nsMargin GetScrollMargin() const {
return nsMargin(mScrollMargin.Get(mozilla::eSideTop).ToAppUnits(),
// Return true if either the start or end side in the axis is 'auto'.
// (defined in WritingModes.h since we need the full WritingMode type)
inline bool HasBlockAxisAuto(mozilla::WritingMode aWM) const;
inline bool HasInlineAxisAuto(mozilla::WritingMode aWM) const;
inline bool HasAuto(mozilla::LogicalAxis, mozilla::WritingMode) const;
mozilla::StyleRect<mozilla::LengthPercentageOrAuto> mMargin;
mozilla::StyleRect<mozilla::StyleLength> mScrollMargin;
// TODO: Add support for overflow-clip-margin: <visual-box> and maybe
// per-axis/side clipping, see
mozilla::StyleLength mOverflowClipMargin;
mozilla::StyleRect<mozilla::NonNegativeLengthPercentage> mPadding;
mozilla::StyleRect<mozilla::NonNegativeLengthPercentageOrAuto> mScrollPadding;
inline bool IsWidthDependent() const {
return !mPadding.All(
[](const auto& aLength) { return aLength.ConvertsToLength(); });
bool GetPadding(nsMargin& aPadding) const {
if (IsWidthDependent()) {
return false;
for (const auto side : mozilla::AllPhysicalSides()) {
// Clamp negative calc() to 0.
aPadding.Side(side) = std::max(mPadding.Get(side).ToLength(), 0);
return true;
// Border widths are rounded to the nearest-below integer number of pixels,
// but values between zero and one device pixels are always rounded up to
// one device pixel.
#define NS_ROUND_BORDER_TO_PIXELS(l, tpp) \
((l) == 0) ? 0 : std::max((tpp), (l) / (tpp) * (tpp))
// Returns if the given border style type is visible or not
static bool IsVisibleBorderStyle(mozilla::StyleBorderStyle aStyle) {
return (aStyle != mozilla::StyleBorderStyle::None &&
aStyle != mozilla::StyleBorderStyle::Hidden);
void TriggerImageLoads(mozilla::dom::Document&, const nsStyleBorder*);
// Return whether aStyle is a visible style. Invisible styles cause
// the relevant computed border width to be 0.
// Note that this does *not* consider the effects of 'border-image':
// if border-style is none, but there is a loaded border image,
// HasVisibleStyle will be false even though there *is* a border.
bool HasVisibleStyle(mozilla::Side aSide) const {
return IsVisibleBorderStyle(mBorderStyle[aSide]);
// aBorderWidth is in twips
void SetBorderWidth(mozilla::Side aSide, nscoord aBorderWidth,
nscoord aAppUnitsPerDevPixel) {
nscoord roundedWidth =
NS_ROUND_BORDER_TO_PIXELS(aBorderWidth, aAppUnitsPerDevPixel);
mBorder.Side(aSide) = roundedWidth;
if (HasVisibleStyle(aSide)) {
mComputedBorder.Side(aSide) = roundedWidth;
// Get the computed border (plus rounding). This does consider the
// effects of 'border-style: none', but does not consider
// 'border-image'.
const nsMargin& GetComputedBorder() const { return mComputedBorder; }
bool HasBorder() const {
return mComputedBorder != nsMargin(0, 0, 0, 0) ||
// Get the actual border width for a particular side, in appunits. Note that
// this is zero if and only if there is no border to be painted for this
// side. That is, this value takes into account the border style and the
// value is rounded to the nearest device pixel by NS_ROUND_BORDER_TO_PIXELS.
nscoord GetComputedBorderWidth(mozilla::Side aSide) const {
return GetComputedBorder().Side(aSide);
mozilla::StyleBorderStyle GetBorderStyle(mozilla::Side aSide) const {
NS_ASSERTION(aSide <= mozilla::eSideLeft, "bad side");
return mBorderStyle[aSide];
void SetBorderStyle(mozilla::Side aSide, mozilla::StyleBorderStyle aStyle) {
NS_ASSERTION(aSide <= mozilla::eSideLeft, "bad side");
mBorderStyle[aSide] = aStyle;
mComputedBorder.Side(aSide) =
(HasVisibleStyle(aSide) ? mBorder.Side(aSide) : 0);
inline bool IsBorderImageSizeAvailable() const {
return mBorderImageSource.IsSizeAvailable();
nsMargin GetImageOutset() const;
imgIRequest* GetBorderImageRequest() const {
return mBorderImageSource.GetImageRequest();
mozilla::StyleBorderRadius mBorderRadius; // coord, percent
mozilla::StyleImage mBorderImageSource;
mozilla::StyleBorderImageWidth mBorderImageWidth;
mozilla::StyleNonNegativeLengthOrNumberRect mBorderImageOutset;
mozilla::StyleBorderImageSlice mBorderImageSlice; // factor, percent
mozilla::StyleBorderImageRepeat mBorderImageRepeatH;
mozilla::StyleBorderImageRepeat mBorderImageRepeatV;
mozilla::StyleFloatEdge mFloatEdge;
mozilla::StyleBoxDecorationBreak mBoxDecorationBreak;
mozilla::StyleBorderStyle mBorderStyle[4]; // StyleBorderStyle::*
// the colors to use for a simple border.
// not used for -moz-border-colors
mozilla::StyleColor mBorderTopColor;
mozilla::StyleColor mBorderRightColor;
mozilla::StyleColor mBorderBottomColor;
mozilla::StyleColor mBorderLeftColor;
mozilla::StyleColor& BorderColorFor(mozilla::Side aSide) {
switch (aSide) {
case mozilla::eSideTop:
return mBorderTopColor;
case mozilla::eSideRight:
return mBorderRightColor;
case mozilla::eSideBottom:
return mBorderBottomColor;
case mozilla::eSideLeft:
return mBorderLeftColor;
return mBorderTopColor;
const mozilla::StyleColor& BorderColorFor(mozilla::Side aSide) const {
switch (aSide) {
case mozilla::eSideTop:
return mBorderTopColor;
case mozilla::eSideRight:
return mBorderRightColor;
case mozilla::eSideBottom:
return mBorderBottomColor;
case mozilla::eSideLeft:
return mBorderLeftColor;
return mBorderTopColor;
static mozilla::StyleColor nsStyleBorder::*BorderColorFieldFor(
mozilla::Side aSide) {
switch (aSide) {
case mozilla::eSideTop:
return &nsStyleBorder::mBorderTopColor;
case mozilla::eSideRight:
return &nsStyleBorder::mBorderRightColor;
case mozilla::eSideBottom:
return &nsStyleBorder::mBorderBottomColor;
case mozilla::eSideLeft:
return &nsStyleBorder::mBorderLeftColor;
return nullptr;
nsStyleBorder& operator=(const nsStyleBorder&) = delete;
// mComputedBorder holds the CSS2.1 computed border-width values.
// In particular, these widths take into account the border-style
// for the relevant side, and the values are rounded to the nearest
// device pixel (which is not part of the definition of computed
// values). The presence or absence of a border-image does not
// affect border-width values.
nsMargin mComputedBorder;
// mBorder holds the nscoord values for the border widths as they
// would be if all the border-style values were visible (not hidden
// or none). This member exists so that when we create structs
// using the copy constructor during style resolution the new
// structs will know what the specified values of the border were in
// case they have more specific rules setting the border style.
// Note that this isn't quite the CSS specified value, since this
// has had the enumerated border widths converted to lengths, and
// all lengths converted to twips. But it's not quite the computed
// value either. The values are rounded to the nearest device pixel.
nsMargin mBorder;
// This is the specified value of outline-width, but with length values
// computed to absolute. mActualOutlineWidth stores the outline-width
// value used by layout. (We must store mOutlineWidth for the same
// style struct resolution reasons that we do nsStyleBorder::mBorder;
// see that field's comment.)
nscoord mOutlineWidth;
mozilla::Length mOutlineOffset;
mozilla::StyleColor mOutlineColor;
mozilla::StyleOutlineStyle mOutlineStyle;
nscoord GetOutlineWidth() const { return mActualOutlineWidth; }
bool ShouldPaintOutline() const {
if (mOutlineStyle.IsAuto()) {
return true;
if (GetOutlineWidth() > 0) {
mOutlineStyle.AsBorderStyle() != mozilla::StyleBorderStyle::None,
"outline-style: none implies outline-width of zero");
return true;
return false;
nsSize EffectiveOffsetFor(const nsRect& aRect) const;
// The actual value of outline-width is the computed value (an absolute
// length, forced to zero when outline-style is none) rounded to device
// pixels. This is the value used by layout.
nscoord mActualOutlineWidth;
void TriggerImageLoads(mozilla::dom::Document&, const nsStyleList*);
nsStyleList& operator=(const nsStyleList& aOther) = delete;
nsChangeHint CalcDifference(const nsStyleList& aNewData,
const mozilla::ComputedStyle& aOldStyle) const;
already_AddRefed<nsIURI> GetListStyleImageURI() const;
mozilla::StyleListStylePosition mListStylePosition;
mozilla::StyleListStyleType mListStyleType;
mozilla::StyleQuotes mQuotes;
mozilla::StyleImage mListStyleImage;
using StylePageOrientation = mozilla::StylePageOrientation;
using StylePageSize = mozilla::StylePageSize;
using StylePageName = mozilla::StylePageName;
// page-size property.
StylePageSize mSize = StylePageSize::Auto();
// page-name property.
StylePageName mPage = StylePageName::Auto();
// page-orientation property.
StylePageOrientation mPageOrientation = StylePageOrientation::Upright;
using LengthPercentageOrAuto = mozilla::LengthPercentageOrAuto;
using Position = mozilla::Position;
template <typename T>
using StyleRect = mozilla::StyleRect<T>;
using StyleSize = mozilla::StyleSize;
using StyleMaxSize = mozilla::StyleMaxSize;
using WritingMode = mozilla::WritingMode;
using LogicalAxis = mozilla::LogicalAxis;
using StyleImplicitGridTracks = mozilla::StyleImplicitGridTracks;
using ComputedStyle = mozilla::ComputedStyle;
using StyleAlignSelf = mozilla::StyleAlignSelf;
using StyleJustifySelf = mozilla::StyleJustifySelf;
nsChangeHint CalcDifference(const nsStylePosition& aNewData,
const ComputedStyle& aOldStyle) const;
// Returns whether we need to compute an hypothetical position if we were
// absolutely positioned.
bool NeedsHypotheticalPositionIfAbsPos() const {
return (mOffset.Get(mozilla::eSideRight).IsAuto() &&
mOffset.Get(mozilla::eSideLeft).IsAuto()) ||
(mOffset.Get(mozilla::eSideTop).IsAuto() &&
const mozilla::StyleContainIntrinsicSize& ContainIntrinsicBSize(
const WritingMode& aWM) const;
const mozilla::StyleContainIntrinsicSize& ContainIntrinsicISize(
const WritingMode& aWM) const;
* Return the used value for 'align-self' given our parent ComputedStyle
* (or null for the root).
StyleAlignSelf UsedAlignSelf(const ComputedStyle*) const;
* Return the used value for 'justify-self' given our parent ComputedStyle
* aParent (or null for the root).
StyleJustifySelf UsedJustifySelf(const ComputedStyle*) const;
* Return the used value for 'justify/align-self' in aAxis given our parent
* ComputedStyle aParent (or null for the root).
* (defined in WritingModes.h since we need the full WritingMode type)
inline mozilla::StyleAlignFlags UsedSelfAlignment(
LogicalAxis aAxis, const mozilla::ComputedStyle* aParent) const;
* Return the used value for 'justify/align-content' in aAxis.
* (defined in WritingModes.h since we need the full WritingMode type)
inline mozilla::StyleContentDistribution UsedContentAlignment(
LogicalAxis aAxis) const;
Position mObjectPosition;
StyleRect<LengthPercentageOrAuto> mOffset;
StyleSize mWidth;
StyleSize mMinWidth;
StyleMaxSize mMaxWidth;
StyleSize mHeight;
StyleSize mMinHeight;
StyleMaxSize mMaxHeight;
// 'auto' or a `<dashed-ident>` referencing an anchor positioning anchor
// element.
mozilla::StylePositionAnchor mPositionAnchor;
mozilla::StylePositionVisibility mPositionVisibility;
mozilla::StylePositionTryOptions mPositionTryOptions;
mozilla::StylePositionTryOrder mPositionTryOrder;
mozilla::StyleInsetArea mInsetArea;
mozilla::StyleFlexBasis mFlexBasis;
StyleImplicitGridTracks mGridAutoColumns;
StyleImplicitGridTracks mGridAutoRows;
mozilla::StyleAspectRatio mAspectRatio;
mozilla::StyleGridAutoFlow mGridAutoFlow;
mozilla::StyleMasonryAutoFlow mMasonryAutoFlow;
mozilla::StyleAlignContent mAlignContent;
mozilla::StyleAlignItems mAlignItems;
mozilla::StyleAlignSelf mAlignSelf;
mozilla::StyleJustifyContent mJustifyContent;
mozilla::StyleComputedJustifyItems mJustifyItems;
mozilla::StyleJustifySelf mJustifySelf;
mozilla::StyleFlexDirection mFlexDirection;
mozilla::StyleFlexWrap mFlexWrap;
mozilla::StyleObjectFit mObjectFit;
mozilla::StyleBoxSizing mBoxSizing;
int32_t mOrder;
float mFlexGrow;
float mFlexShrink;
mozilla::StyleZIndex mZIndex;
mozilla::StyleGridTemplateComponent mGridTemplateColumns;
mozilla::StyleGridTemplateComponent mGridTemplateRows;
mozilla::StyleGridTemplateAreas mGridTemplateAreas;
mozilla::StyleGridLine mGridColumnStart;
mozilla::StyleGridLine mGridColumnEnd;
mozilla::StyleGridLine mGridRowStart;
mozilla::StyleGridLine mGridRowEnd;
mozilla::NonNegativeLengthPercentageOrNormal mColumnGap;
mozilla::NonNegativeLengthPercentageOrNormal mRowGap;
mozilla::StyleContainIntrinsicSize mContainIntrinsicWidth;
mozilla::StyleContainIntrinsicSize mContainIntrinsicHeight;
// Logical-coordinate accessors for width and height properties,
// given a WritingMode value. The definitions of these methods are
// found in WritingModes.h (after the WritingMode class is fully
// declared).
inline const StyleSize& ISize(WritingMode) const;
inline const StyleSize& MinISize(WritingMode) const;
inline const StyleMaxSize& MaxISize(WritingMode) const;
inline const StyleSize& BSize(WritingMode) const;
inline const StyleSize& MinBSize(WritingMode) const;
inline const StyleMaxSize& MaxBSize(WritingMode) const;
inline const StyleSize& Size(LogicalAxis, WritingMode) const;
inline const StyleSize& MinSize(LogicalAxis, WritingMode) const;
inline const StyleMaxSize& MaxSize(LogicalAxis, WritingMode) const;
inline bool ISizeDependsOnContainer(WritingMode) const;
inline bool MinISizeDependsOnContainer(WritingMode) const;
inline bool MaxISizeDependsOnContainer(WritingMode) const;
inline bool BSizeDependsOnContainer(WritingMode) const;
inline bool MinBSizeDependsOnContainer(WritingMode) const;
inline bool MaxBSizeDependsOnContainer(WritingMode) const;
template <typename SizeOrMaxSize>
static bool ISizeCoordDependsOnContainer(const SizeOrMaxSize& aCoord) {
if (aCoord.IsLengthPercentage()) {
return aCoord.AsLengthPercentage().HasPercent();
return aCoord.IsFitContent() || aCoord.IsMozAvailable();
template <typename SizeOrMaxSize>
static bool BSizeCoordDependsOnContainer(const SizeOrMaxSize& aCoord) {
return aCoord.IsLengthPercentage() &&
// Note the difference between this and
// ComputedStyle::HasTextDecorationLines.
bool HasTextDecorationLines() const {
return mTextDecorationLine != mozilla::StyleTextDecorationLine::NONE &&
mTextDecorationLine !=
mozilla::StyleTextOverflow mTextOverflow;
mozilla::StyleTextDecorationLine mTextDecorationLine;
mozilla::StyleTextDecorationStyle mTextDecorationStyle;
mozilla::StyleUnicodeBidi mUnicodeBidi;
mozilla::StyleInitialLetter mInitialLetter;
mozilla::StyleColor mTextDecorationColor;
mozilla::StyleTextDecorationLength mTextDecorationThickness;
explicit nsStyleText(const mozilla::dom::Document&);
mozilla::StyleAbsoluteColor mColor;
mozilla::StyleForcedColorAdjust mForcedColorAdjust;
mozilla::StyleTextTransform mTextTransform;
mozilla::StyleTextAlign mTextAlign;
mozilla::StyleTextAlignLast mTextAlignLast;
mozilla::StyleTextJustify mTextJustify;
mozilla::StyleWhiteSpaceCollapse mWhiteSpaceCollapse =
mozilla::StyleTextWrapMode mTextWrapMode = mozilla::StyleTextWrapMode::Wrap;
mozilla::StyleLineBreak mLineBreak = mozilla::StyleLineBreak::Auto;
mozilla::StyleWordBreak mWordBreak = mozilla::StyleWordBreak::Normal;
mozilla::StyleOverflowWrap mOverflowWrap = mozilla::StyleOverflowWrap::Normal;
mozilla::StyleHyphens mHyphens;
mozilla::StyleRubyAlign mRubyAlign;
mozilla::StyleRubyPosition mRubyPosition;
mozilla::StyleTextSizeAdjust mTextSizeAdjust;
mozilla::StyleTextCombineUpright mTextCombineUpright;
mozilla::StyleMozControlCharacterVisibility mMozControlCharacterVisibility;
mozilla::StyleTextEmphasisPosition mTextEmphasisPosition;
mozilla::StyleTextRendering mTextRendering;
mozilla::StyleColor mTextEmphasisColor;
mozilla::StyleColor mWebkitTextFillColor;
mozilla::StyleColor mWebkitTextStrokeColor;
mozilla::StyleNonNegativeLengthOrNumber mTabSize;
mozilla::LengthPercentage mWordSpacing;
mozilla::StyleLetterSpacing mLetterSpacing;
mozilla::StyleTextIndent mTextIndent;
mozilla::LengthPercentageOrAuto mTextUnderlineOffset;
mozilla::StyleTextDecorationSkipInk mTextDecorationSkipInk;
mozilla::StyleTextUnderlinePosition mTextUnderlinePosition;
mozilla::StyleAu mWebkitTextStrokeWidth;
mozilla::StyleArcSlice<mozilla::StyleSimpleShadow> mTextShadow;
mozilla::StyleTextEmphasisStyle mTextEmphasisStyle;
mozilla::StyleHyphenateCharacter mHyphenateCharacter =
mozilla::StyleTextSecurity mWebkitTextSecurity =
mozilla::StyleTextWrapStyle mTextWrapStyle =
char16_t TextSecurityMaskChar() const {
switch (mWebkitTextSecurity) {
case mozilla::StyleTextSecurity::None:
return 0;
case mozilla::StyleTextSecurity::Circle:
return 0x25E6;
case mozilla::StyleTextSecurity::Disc:
return 0x2022;
case mozilla::StyleTextSecurity::Square:
return 0x25A0;
MOZ_ASSERT_UNREACHABLE("unknown StyleTextSecurity value!");
return 0;
mozilla::StyleWordBreak EffectiveWordBreak() const {
if (mWordBreak == mozilla::StyleWordBreak::BreakWord) {
return mozilla::StyleWordBreak::Normal;
return mWordBreak;
mozilla::StyleOverflowWrap EffectiveOverflowWrap() const {
if (mWordBreak == mozilla::StyleWordBreak::BreakWord) {
return mozilla::StyleOverflowWrap::Anywhere;
return mOverflowWrap;
bool WhiteSpaceIsSignificant() const {
return mWhiteSpaceCollapse != mozilla::StyleWhiteSpaceCollapse::Collapse &&
mWhiteSpaceCollapse !=
bool WhiteSpaceCanHangOrVisuallyCollapse() const {
// This was originally expressed in nsTextFrame in terms of:
// mWhiteSpace != StyleWhiteSpace::BreakSpaces &&
// WhiteSpaceCanWrapStyle() &&
// WhiteSpaceIsSignificant()
// which simplifies to:
return mTextWrapMode == mozilla::StyleTextWrapMode::Wrap &&
mWhiteSpaceCollapse != mozilla::StyleWhiteSpaceCollapse::BreakSpaces;
bool NewlineIsSignificantStyle() const {
return mWhiteSpaceCollapse == mozilla::StyleWhiteSpaceCollapse::Preserve ||
mWhiteSpaceCollapse ==
mozilla::StyleWhiteSpaceCollapse::PreserveBreaks ||
mWhiteSpaceCollapse == mozilla::StyleWhiteSpaceCollapse::BreakSpaces;
bool WhiteSpaceOrNewlineIsSignificant() const {
return NewlineIsSignificantStyle() || WhiteSpaceIsSignificant();
bool TabIsSignificant() const {
return mWhiteSpaceCollapse == mozilla::StyleWhiteSpaceCollapse::Preserve ||
mWhiteSpaceCollapse == mozilla::StyleWhiteSpaceCollapse::BreakSpaces;
bool WhiteSpaceCanWrapStyle() const {
return mTextWrapMode == mozilla::StyleTextWrapMode::Wrap;
bool WordCanWrapStyle() const {
if (!WhiteSpaceCanWrapStyle()) {
return false;
auto owrap = EffectiveOverflowWrap();
return owrap == mozilla::StyleOverflowWrap::BreakWord ||
owrap == mozilla::StyleOverflowWrap::Anywhere;
bool HasEffectiveTextEmphasis() const {
if (mTextEmphasisStyle.IsNone()) {
return false;
if (mTextEmphasisStyle.IsString() &&
mTextEmphasisStyle.AsString().AsString().IsEmpty()) {
return false;
return true;
mozilla::StyleTextAlign TextAlignForLastLine() const {
switch (mTextAlignLast) {
case mozilla::StyleTextAlignLast::Auto:
// 'text-align-last: auto' is equivalent to the value of the
// 'text-align' property except when 'text-align' is set to 'justify',
// in which case it is 'justify' when 'text-justify' is 'distribute' and
// 'start' otherwise.
// XXX: the code below will have to change when we implement
// text-justify
if (mTextAlign == mozilla::StyleTextAlign::Justify) {
return mozilla::StyleTextAlign::Start;
return mTextAlign;
case mozilla::StyleTextAlignLast::Center:
return mozilla::StyleTextAlign::Center;
case mozilla::StyleTextAlignLast::Start:
return mozilla::StyleTextAlign::Start;
case mozilla::StyleTextAlignLast::End:
return mozilla::StyleTextAlign::End;
case mozilla::StyleTextAlignLast::Left:
return mozilla::StyleTextAlign::Left;
case mozilla::StyleTextAlignLast::Right:
return mozilla::StyleTextAlign::Right;
case mozilla::StyleTextAlignLast::Justify:
return mozilla::StyleTextAlign::Justify;
return mozilla::StyleTextAlign::Start;
bool HasWebkitTextStroke() const { return mWebkitTextStrokeWidth > 0; }
bool HasTextShadow() const { return !mTextShadow.IsEmpty(); }
// The aContextFrame argument on each of these is the frame this
// style struct is for. If the frame is for SVG text or inside ruby,
// the return value will be massaged to be something that makes sense
// for those cases.
inline bool NewlineIsSignificant(const nsTextFrame* aContextFrame) const;
inline bool WhiteSpaceCanWrap(const nsIFrame* aContextFrame) const;
inline bool WordCanWrap(const nsIFrame* aContextFrame) const;
mozilla::LogicalSide TextEmphasisSide(mozilla::WritingMode aWM) const;
struct MOZ_NEEDS_MEMMOVABLE_MEMBERS nsStyleVisibility {
explicit nsStyleVisibility(const mozilla::dom::Document&);
bool IsVisible() const {
return mVisible == mozilla::StyleVisibility::Visible;
bool IsCollapse() const {
return mVisible == mozilla::StyleVisibility::Collapse;
bool IsVisibleOrCollapsed() const {
return mVisible == mozilla::StyleVisibility::Visible ||
mVisible == mozilla::StyleVisibility::Collapse;
bool UseLegacyCollapseBehavior() const {
return mMozBoxCollapse == mozilla::StyleMozBoxCollapse::Legacy;
* Given an image request, returns the orientation that should be used
* on the image. The returned orientation may differ from the style
* struct's orientation member value, if the image request is not of the
* same origin.
* @param aRequest The image request used to determine if same origin.
mozilla::StyleImageOrientation UsedImageOrientation(
imgIRequest* aRequest) const {
return UsedImageOrientation(aRequest, mImageOrientation);
* Given an image request and an orientation, returns the orientation
* that should be used on the image. The returned orientation may differ
* from the input orientation if the image request is not of the same
* origin.
* @param aRequest The image request used to determine if same origin.
* @param aOrientation The input orientation.
static mozilla::StyleImageOrientation UsedImageOrientation(
imgIRequest* aRequest, mozilla::StyleImageOrientation aOrientation);
mozilla::StyleDirection mDirection;
mozilla::StyleVisibility mVisible;
mozilla::StyleImageRendering mImageRendering;
mozilla::StyleWritingModeProperty mWritingMode;
mozilla::StyleTextOrientation mTextOrientation;
mozilla::StyleMozBoxCollapse mMozBoxCollapse;
mozilla::StylePrintColorAdjust mPrintColorAdjust;
mozilla::StyleImageOrientation mImageOrientation;
namespace mozilla {
// Note that IsAuto() does not exclude the possibility that `left` or `right`
// is set; it refers only to behavior in horizontal typographic mode.
inline bool StyleTextUnderlinePosition::IsAuto() const {
return !(*this & (StyleTextUnderlinePosition::FROM_FONT |
inline bool StyleTextUnderlinePosition::IsFromFont() const {
return bool(*this & StyleTextUnderlinePosition::FROM_FONT);
inline bool StyleTextUnderlinePosition::IsUnder() const {
return bool(*this & StyleTextUnderlinePosition::UNDER);
inline bool StyleTextUnderlinePosition::IsLeft() const {
return bool(*this & StyleTextUnderlinePosition::LEFT);
inline bool StyleTextUnderlinePosition::IsRight() const {
return bool(*this & StyleTextUnderlinePosition::RIGHT);
struct StyleTransition {
StyleTransition() = default;
explicit StyleTransition(const StyleTransition& aCopy);
const StyleComputedTimingFunction& GetTimingFunction() const {
return mTimingFunction;
const StyleTime& GetDelay() const { return mDelay; }
const StyleTime& GetDuration() const { return mDuration; }
const StyleTransitionProperty& GetProperty() const { return mProperty; }
StyleTransitionBehavior GetBehavior() const { return mBehavior; }
bool operator==(const StyleTransition& aOther) const;
bool operator!=(const StyleTransition& aOther) const {
return !(*this == aOther);
StyleComputedTimingFunction mTimingFunction{
StyleTime mDuration{0.0};
StyleTime mDelay{0.0};
StyleTransitionProperty mProperty{StyleTransitionProperty::NonCustom(
StyleTransitionBehavior mBehavior = StyleTransitionBehavior::Normal;
struct StyleAnimation {
StyleAnimation() = default;
explicit StyleAnimation(const StyleAnimation& aCopy);
const StyleComputedTimingFunction& GetTimingFunction() const {
return mTimingFunction;
const StyleTime& GetDelay() const { return mDelay; }
const StyleTime& GetDuration() const { return mDuration; }
nsAtom* GetName() const { return mName._0.AsAtom(); }
StyleAnimationDirection GetDirection() const { return mDirection; }
StyleAnimationFillMode GetFillMode() const { return mFillMode; }
StyleAnimationPlayState GetPlayState() const { return mPlayState; }
float GetIterationCount() const { return mIterationCount._0; }
StyleAnimationComposition GetComposition() const { return mComposition; }
const StyleAnimationTimeline& GetTimeline() const { return mTimeline; }
bool operator==(const StyleAnimation& aOther) const;
bool operator!=(const StyleAnimation& aOther) const {
return !(*this == aOther);
StyleComputedTimingFunction mTimingFunction{
StyleTime mDuration{0.0f};
StyleTime mDelay{0.0f};
StyleAnimationName mName;
StyleAnimationDirection mDirection = StyleAnimationDirection::Normal;
StyleAnimationFillMode mFillMode = StyleAnimationFillMode::None;
StyleAnimationPlayState mPlayState = StyleAnimationPlayState::Running;
StyleAnimationIterationCount mIterationCount{1.0f};
StyleAnimationComposition mComposition = StyleAnimationComposition::Replace;
StyleAnimationTimeline mTimeline{StyleAnimationTimeline::Auto()};
struct StyleScrollTimeline {
StyleScrollTimeline() = default;
explicit StyleScrollTimeline(const StyleScrollTimeline& aCopy) = default;
nsAtom* GetName() const { return mName._0.AsAtom(); }
StyleScrollAxis GetAxis() const { return mAxis; }
bool operator==(const StyleScrollTimeline& aOther) const {
return mName == aOther.mName && mAxis == aOther.mAxis;
bool operator!=(const StyleScrollTimeline& aOther) const {
return !(*this == aOther);
StyleScrollTimelineName mName;
StyleScrollAxis mAxis = StyleScrollAxis::Block;
struct StyleViewTimeline {
StyleViewTimeline() = default;
explicit StyleViewTimeline(const StyleViewTimeline& aCopy) = default;
nsAtom* GetName() const { return mName._0.AsAtom(); }
StyleScrollAxis GetAxis() const { return mAxis; }
const StyleViewTimelineInset& GetInset() const { return mInset; }
bool operator==(const StyleViewTimeline& aOther) const {
return mName == aOther.mName && mAxis == aOther.mAxis &&
mInset == aOther.mInset;
bool operator!=(const StyleViewTimeline& aOther) const {
return !(*this == aOther);
StyleScrollTimelineName mName;
StyleScrollAxis mAxis = StyleScrollAxis::Block;
StyleViewTimelineInset mInset;
} // namespace mozilla
void TriggerImageLoads(mozilla::dom::Document&, const nsStyleDisplay*);
using StyleContain = mozilla::StyleContain;
using StyleContentVisibility = mozilla::StyleContentVisibility;
nsChangeHint CalcDifference(const nsStyleDisplay& aNewData,
const mozilla::ComputedStyle& aOldStyle) const;
nsChangeHint CalcTransformPropertyDifference(
const nsStyleDisplay& aNewData) const;
mozilla::StyleDisplay mDisplay;
// Saved mDisplay for position:absolute/fixed and float:left/right; otherwise
// equal to mDisplay.
mozilla::StyleDisplay mOriginalDisplay;
// Equal to mContain plus any implicit containment from mContentVisibility and
// mContainerType.
mozilla::StyleContentVisibility mContentVisibility;
mozilla::StyleContainerType mContainerType;
bool IsQueryContainer() const {
return mContainerType != mozilla::StyleContainerType::Normal;
mozilla::StyleAppearance mAppearance;
mozilla::StyleContain mContain;
// Equal to mContain plus any implicit containment from mContentVisibility and
// mContainerType.
mozilla::StyleContain mEffectiveContainment;
mozilla::StyleAppearance mDefaultAppearance;
mozilla::StylePositionProperty mPosition;
mozilla::StyleFloat mFloat;
mozilla::StyleClear mClear;
mozilla::StyleBreakWithin mBreakInside;
mozilla::StyleBreakBetween mBreakBefore;
mozilla::StyleBreakBetween mBreakAfter;
mozilla::StyleOverflow mOverflowX;
mozilla::StyleOverflow mOverflowY;
mozilla::StyleOverflowClipBox mOverflowClipBoxBlock;
mozilla::StyleOverflowClipBox mOverflowClipBoxInline;
mozilla::StyleScrollbarGutter mScrollbarGutter;
mozilla::StyleResize mResize;
mozilla::StyleOrient mOrient;
mozilla::StyleIsolation mIsolation;
mozilla::StyleTopLayer mTopLayer;
mozilla::StyleTouchAction mTouchAction;
mozilla::StyleScrollBehavior mScrollBehavior;
mozilla::StyleOverscrollBehavior mOverscrollBehaviorX;
mozilla::StyleOverscrollBehavior mOverscrollBehaviorY;
mozilla::StyleOverflowAnchor mOverflowAnchor;
mozilla::StyleScrollSnapAlign mScrollSnapAlign;
mozilla::StyleScrollSnapStop mScrollSnapStop;
mozilla::StyleScrollSnapType mScrollSnapType;
mozilla::StyleBackfaceVisibility mBackfaceVisibility;
mozilla::StyleTransformStyle mTransformStyle;
mozilla::StyleTransformBox mTransformBox;
mozilla::StyleTransform mTransform;
mozilla::StyleRotate mRotate;
mozilla::StyleTranslate mTranslate;
mozilla::StyleScale mScale;
mozilla::StyleContainerName mContainerName;
mozilla::StyleWillChange mWillChange;
mozilla::StyleOffsetPath mOffsetPath;
mozilla::LengthPercentage mOffsetDistance;
mozilla::StyleOffsetRotate mOffsetRotate;
mozilla::StylePositionOrAuto mOffsetAnchor;
mozilla::StyleOffsetPosition mOffsetPosition;
mozilla::StyleTransformOrigin mTransformOrigin;
mozilla::StylePerspective mChildPerspective;
mozilla::Position mPerspectiveOrigin;
mozilla::StyleVerticalAlign mVerticalAlign;
mozilla::StyleBaselineSource mBaselineSource;
mozilla::StyleLineClamp mWebkitLineClamp;
// The threshold used for extracting a shape from shape-outside: <image>.
float mShapeImageThreshold = 0.0f;
mozilla::StyleZoom mZoom = mozilla::StyleZoom::ONE;
// The margin around a shape-outside: <image>.
mozilla::NonNegativeLengthPercentage mShapeMargin;
mozilla::StyleShapeOutside mShapeOutside;
// 'none', 'all', or a list of one or more `<dashed-ident>` identifiers that
// anchor positioned elements may reference.
mozilla::StyleAnchorName mAnchorName;
// 'none', 'all', or a list of one or more `<dashed-ident>` identifiers that
// may identify anchor positioning anchor elements.
mozilla::StyleAnchorScope mAnchorScope;
mozilla::Maybe<mozilla::WindowButtonType> GetWindowButtonType() const {
if (MOZ_LIKELY(mDefaultAppearance == mozilla::StyleAppearance::None)) {
return mozilla::Nothing();
switch (mDefaultAppearance) {
case mozilla::StyleAppearance::MozWindowButtonMaximize:
case mozilla::StyleAppearance::MozWindowButtonRestore:
return Some(mozilla::WindowButtonType::Maximize);
case mozilla::StyleAppearance::MozWindowButtonMinimize:
return Some(mozilla::WindowButtonType::Minimize);
case mozilla::StyleAppearance::MozWindowButtonClose:
return Some(mozilla::WindowButtonType::Close);
return mozilla::Nothing();
bool HasAppearance() const {
return EffectiveAppearance() != mozilla::StyleAppearance::None;
mozilla::StyleAppearance EffectiveAppearance() const {
if (MOZ_LIKELY(mAppearance == mozilla::StyleAppearance::None)) {
return mAppearance;
switch (mAppearance) {
case mozilla::StyleAppearance::Auto:
case mozilla::StyleAppearance::Button:
case mozilla::StyleAppearance::Searchfield:
case mozilla::StyleAppearance::Textarea:
case mozilla::StyleAppearance::Checkbox:
case mozilla::StyleAppearance::Radio:
case mozilla::StyleAppearance::Menulist:
case mozilla::StyleAppearance::Listbox:
case mozilla::StyleAppearance::Meter:
case mozilla::StyleAppearance::ProgressBar:
// These are all the values that behave like `auto`.
return mDefaultAppearance;
case mozilla::StyleAppearance::Textfield:
// `appearance: textfield` should behave like `auto` on all elements
// except <input type=search/number/password> elements, which we
// identify using the internal -moz-default-appearance property.
if (mDefaultAppearance == mozilla::StyleAppearance::Searchfield ||
mDefaultAppearance == mozilla::StyleAppearance::NumberInput ||
mDefaultAppearance == mozilla::StyleAppearance::PasswordInput) {
return mAppearance;
return mDefaultAppearance;
case mozilla::StyleAppearance::MenulistButton:
// `appearance: menulist-button` should behave like `auto` on all
// elements except for drop down selects, but since we have very little
// difference between menulist and menulist-button handling, we don't
// bother.
return mDefaultAppearance;
return mAppearance;
mozilla::StyleDisplayOutside DisplayOutside() const {
return mDisplay.Outside();
mozilla::StyleDisplayInside DisplayInside() const {
return mDisplay.Inside();
bool IsListItem() const { return mDisplay.IsListItem(); }
bool IsInlineFlow() const { return mDisplay.IsInlineFlow(); }
bool IsInlineInsideStyle() const { return mDisplay.IsInlineInside(); }
bool IsBlockOutsideStyle() const {
return DisplayOutside() == mozilla::StyleDisplayOutside::Block;
bool IsInlineOutsideStyle() const { return mDisplay.IsInlineOutside(); }
bool IsOriginalDisplayInlineOutside() const {
return mOriginalDisplay.IsInlineOutside();
bool IsInnerTableStyle() const { return mDisplay.IsInternalTable(); }
bool IsInternalTableStyleExceptCell() const {
return mDisplay.IsInternalTableExceptCell();
bool IsFloatingStyle() const { return mozilla::StyleFloat::None != mFloat; }
bool IsPositionedStyle() const {
return mPosition != mozilla::StylePositionProperty::Static ||
(mWillChange.bits & mozilla::StyleWillChangeBits::POSITION);
bool IsAbsolutelyPositionedStyle() const {
return mozilla::StylePositionProperty::Absolute == mPosition ||
mozilla::StylePositionProperty::Fixed == mPosition;
bool IsRelativelyOrStickyPositionedStyle() const {
return mozilla::StylePositionProperty::Relative == mPosition ||
mozilla::StylePositionProperty::Sticky == mPosition;
bool IsRelativelyPositionedStyle() const {
return mozilla::StylePositionProperty::Relative == mPosition;
bool IsStickyPositionedStyle() const {
return mozilla::StylePositionProperty::Sticky == mPosition;
bool IsPositionForcingStackingContext() const {
return mozilla::StylePositionProperty::Sticky == mPosition ||
mozilla::StylePositionProperty::Fixed == mPosition;
bool IsRubyDisplayType() const { return mDisplay.IsRuby(); }
bool IsInternalRubyDisplayType() const { return mDisplay.IsInternalRuby(); }
bool IsOutOfFlowStyle() const {
return (IsAbsolutelyPositionedStyle() || IsFloatingStyle());
bool IsScrollableOverflow() const {
// Visible and Clip can be combined but not with other values,
// so checking mOverflowX is enough.
return mOverflowX != mozilla::StyleOverflow::Visible &&
mOverflowX != mozilla::StyleOverflow::Clip;
bool OverflowIsVisibleInBothAxis() const {
return mOverflowX == mozilla::StyleOverflow::Visible &&
mOverflowY == mozilla::StyleOverflow::Visible;
bool IsContainPaint() const {
// Short circuit for no containment whatsoever
if (!mEffectiveContainment) {
return false;
return (mEffectiveContainment & StyleContain::PAINT) &&
!IsInternalRubyDisplayType() && !IsInternalTableStyleExceptCell();
bool IsContainLayout() const {
// Short circuit for no containment whatsoever
if (!mEffectiveContainment) {
return false;
// Note: The spec for layout containment says it should
// have no effect on non-atomic, inline-level boxes. We
// don't check for these here because we don't know
// what type of element is involved. Callers are
// responsible for checking if the box in question is
// non-atomic and inline-level, and creating an
// exemption as necessary.
return (mEffectiveContainment & StyleContain::LAYOUT) &&
!IsInternalRubyDisplayType() && !IsInternalTableStyleExceptCell();
bool IsContainStyle() const {
return !!(mEffectiveContainment & StyleContain::STYLE);
bool IsContainAny() const { return !!mEffectiveContainment; }
// This is similar to PrecludesSizeContainmentOrContentVisibility, but also
// takes into account whether or not the given frame is a non-atomic,
// inline-level box.
bool PrecludesSizeContainmentOrContentVisibilityWithFrame(
const nsIFrame&) const;
StyleContentVisibility ContentVisibility(const nsIFrame&) const;
/* Returns whether the element has the transform property or a related
* property. */
bool HasTransformStyle() const {
return HasTransformProperty() || HasIndividualTransform() ||
mTransformStyle == mozilla::StyleTransformStyle::Preserve3d ||
(mWillChange.bits & mozilla::StyleWillChangeBits::TRANSFORM) ||
bool HasTransformProperty() const { return !mTransform._0.IsEmpty(); }
bool HasIndividualTransform() const {
return !mRotate.IsNone() || !mTranslate.IsNone() || !mScale.IsNone();
bool HasPerspectiveStyle() const { return !mChildPerspective.IsNone(); }
bool BackfaceIsHidden() const {
return mBackfaceVisibility == mozilla::StyleBackfaceVisibility::Hidden;
// FIXME(emilio): This should be more fine-grained on each caller to
// BreakBefore() / BreakAfter().
static bool ShouldBreak(mozilla::StyleBreakBetween aBreak) {
switch (aBreak) {
case mozilla::StyleBreakBetween::Left:
case mozilla::StyleBreakBetween::Right:
case mozilla::StyleBreakBetween::Page:
case mozilla::StyleBreakBetween::Always:
return true;
case mozilla::StyleBreakBetween::Auto:
case mozilla::StyleBreakBetween::Avoid:
return false;
MOZ_ASSERT_UNREACHABLE("Unknown break kind");
return false;
// These two methods are deprecated since they do not differentiate paginated
// context and multi-column context. Use nsIFrame::ShouldBreakBefore() /
// nsIFrame::ShouldBreakAfter() instead.
bool BreakBefore() const { return ShouldBreak(mBreakBefore); }
bool BreakAfter() const { return ShouldBreak(mBreakAfter); }
// These are defined in nsStyleStructInlines.h.
// The aContextFrame argument on each of these is the frame this
// style struct is for. If the frame is for SVG text, the return
// value will be massaged to be something that makes sense for
// SVG text.
inline bool IsBlockOutside(const nsIFrame* aContextFrame) const;
inline bool IsInlineOutside(const nsIFrame* aContextFrame) const;
inline mozilla::StyleDisplay GetDisplay(const nsIFrame* aContextFrame) const;
inline bool IsFloating(const nsIFrame* aContextFrame) const;
inline bool IsRelativelyOrStickyPositioned(
const nsIFrame* aContextFrame) const;
// Note: In general, you'd want to call IsRelativelyOrStickyPositioned()
// unless you want to deal with "position:relative" and "position:sticky"
// differently.
inline bool IsRelativelyPositioned(const nsIFrame* aContextFrame) const;
inline bool IsStickyPositioned(const nsIFrame* aContextFrame) const;
inline bool IsAbsolutelyPositioned(const nsIFrame* aContextFrame) const;
// These methods are defined in nsStyleStructInlines.h.
* Returns true when the element has the transform property
* or a related property, and supports CSS transforms.
* aContextFrame is the frame for which this is the nsStyleDisplay.
inline bool HasTransform(const nsIFrame* aContextFrame) const;
* Returns true when the element has the perspective property,
* and supports CSS transforms. aContextFrame is the frame for
* which this is the nsStyleDisplay.
inline bool HasPerspective(const nsIFrame* aContextFrame) const;
inline bool
IsFixedPosContainingBlockForContainLayoutAndPaintSupportingFrames() const;
inline bool IsFixedPosContainingBlockForTransformSupportingFrames() const;
mozilla::ContainSizeAxes GetContainSizeAxes(const nsIFrame& aFrame) const;