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/*
* Copyright (C) 1999 Lars Knoll (knoll@kde.org)
* Copyright (C) 2004-2005 Allan Sandfeld Jensen (kde@carewolf.com)
* Copyright (C) 2006, 2007 Nicholas Shanks (webkit@nickshanks.com)
* Copyright (C) 2005-2019 Apple Inc. All rights reserved.
* Copyright (C) 2007 Alexey Proskuryakov <ap@webkit.org>
* Copyright (C) 2007, 2008 Eric Seidel <eric@webkit.org>
* Copyright (C) 2008, 2009 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
* Copyright (c) 2011, Code Aurora Forum. All rights reserved.
* Copyright (C) Research In Motion Limited 2011. All rights reserved.
* Copyright (C) 2012, 2013 Google Inc. All rights reserved.
* Copyright (C) 2014 Igalia S.L.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Library General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Library General Public License for more details.
*
* You should have received a copy of the GNU Library General Public License
* along with this library; see the file COPYING.LIB. If not, write to
* the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
* Boston, MA 02110-1301, USA.
*/
#include "config.h"
#include "StyleAdjuster.h"
#include "AnimationBase.h"
#include "CSSFontSelector.h"
#include "Element.h"
#include "FrameView.h"
#include "HTMLInputElement.h"
#include "HTMLMarqueeElement.h"
#include "HTMLNames.h"
#include "HTMLSlotElement.h"
#include "HTMLTableElement.h"
#include "HTMLTextAreaElement.h"
#include "MathMLElement.h"
#include "Page.h"
#include "Quirks.h"
#include "RenderBox.h"
#include "RenderStyle.h"
#include "RenderTheme.h"
#include "RuntimeEnabledFeatures.h"
#include "SVGDocument.h"
#include "SVGElement.h"
#include "SVGNames.h"
#include "SVGURIReference.h"
#include "Settings.h"
#include "Text.h"
namespace WebCore {
namespace Style {
using namespace HTMLNames;
Adjuster::Adjuster(const Document& document, const RenderStyle& parentStyle, const RenderStyle* parentBoxStyle, const Element* element)
: m_document(document)
, m_parentStyle(parentStyle)
, m_parentBoxStyle(parentBoxStyle ? *parentBoxStyle : m_parentStyle)
, m_element(element)
{
}
static void addIntrinsicMargins(RenderStyle& style)
{
// Intrinsic margin value.
const int intrinsicMargin = clampToInteger(2 * style.effectiveZoom());
// FIXME: Using width/height alone and not also dealing with min-width/max-width is flawed.
// FIXME: Using "hasQuirk" to decide the margin wasn't set is kind of lame.
if (style.width().isIntrinsicOrAuto()) {
if (style.marginLeft().hasQuirk())
style.setMarginLeft(Length(intrinsicMargin, Fixed));
if (style.marginRight().hasQuirk())
style.setMarginRight(Length(intrinsicMargin, Fixed));
}
if (style.height().isAuto()) {
if (style.marginTop().hasQuirk())
style.setMarginTop(Length(intrinsicMargin, Fixed));
if (style.marginBottom().hasQuirk())
style.setMarginBottom(Length(intrinsicMargin, Fixed));
}
}
static DisplayType equivalentBlockDisplay(const RenderStyle& style, const Document& document)
{
switch (auto display = style.display()) {
case DisplayType::Block:
case DisplayType::Table:
case DisplayType::Box:
case DisplayType::Flex:
case DisplayType::WebKitFlex:
case DisplayType::Grid:
case DisplayType::FlowRoot:
return display;
case DisplayType::ListItem:
// It is a WinIE bug that floated list items lose their bullets, so we'll emulate the quirk, but only in quirks mode.
if (document.inQuirksMode() && style.isFloating())
return DisplayType::Block;
return display;
case DisplayType::InlineTable:
return DisplayType::Table;
case DisplayType::InlineBox:
return DisplayType::Box;
case DisplayType::InlineFlex:
case DisplayType::WebKitInlineFlex:
return DisplayType::Flex;
case DisplayType::InlineGrid:
return DisplayType::Grid;
case DisplayType::Inline:
case DisplayType::InlineBlock:
case DisplayType::TableRowGroup:
case DisplayType::TableHeaderGroup:
case DisplayType::TableFooterGroup:
case DisplayType::TableRow:
case DisplayType::TableColumnGroup:
case DisplayType::TableColumn:
case DisplayType::TableCell:
case DisplayType::TableCaption:
return DisplayType::Block;
case DisplayType::Contents:
ASSERT_NOT_REACHED();
return DisplayType::Contents;
case DisplayType::None:
ASSERT_NOT_REACHED();
return DisplayType::None;
}
ASSERT_NOT_REACHED();
return DisplayType::Block;
}
static inline bool isAtShadowBoundary(const Element& element)
{
auto* parentNode = element.parentNode();
return parentNode && parentNode->isShadowRoot();
}
// CSS requires text-decoration to be reset at each DOM element for tables,
// inline blocks, inline tables, shadow DOM crossings, floating elements,
// and absolute or relatively positioned elements.
static bool doesNotInheritTextDecoration(const RenderStyle& style, const Element* element)
{
return style.display() == DisplayType::Table || style.display() == DisplayType::InlineTable
|| style.display() == DisplayType::InlineBlock || style.display() == DisplayType::InlineBox || (element && isAtShadowBoundary(*element))
|| style.isFloating() || style.hasOutOfFlowPosition();
}
#if ENABLE(OVERFLOW_SCROLLING_TOUCH) || ENABLE(POINTER_EVENTS)
static bool isScrollableOverflow(Overflow overflow)
{
return overflow == Overflow::Scroll || overflow == Overflow::Auto;
}
#endif
#if ENABLE(POINTER_EVENTS)
static OptionSet<TouchAction> computeEffectiveTouchActions(const RenderStyle& style, OptionSet<TouchAction> effectiveTouchActions)
{
// https://w3c.github.io/pointerevents/#determining-supported-touch-behavior
// "A touch behavior is supported if it conforms to the touch-action property of each element between
// the hit tested element and its nearest ancestor with the default touch behavior (including both the
// hit tested element and the element with the default touch behavior)."
bool hasDefaultTouchBehavior = isScrollableOverflow(style.overflowX()) || isScrollableOverflow(style.overflowY());
if (hasDefaultTouchBehavior)
effectiveTouchActions = RenderStyle::initialTouchActions();
auto touchActions = style.touchActions();
if (touchActions == RenderStyle::initialTouchActions())
return effectiveTouchActions;
if (effectiveTouchActions.contains(TouchAction::None))
return { TouchAction::None };
if (effectiveTouchActions.containsAny({ TouchAction::Auto, TouchAction::Manipulation }))
return touchActions;
if (touchActions.containsAny({ TouchAction::Auto, TouchAction::Manipulation }))
return effectiveTouchActions;
auto sharedTouchActions = effectiveTouchActions & touchActions;
if (sharedTouchActions.isEmpty())
return { TouchAction::None };
return sharedTouchActions;
}
#endif
void Adjuster::adjust(RenderStyle& style, const RenderStyle* userAgentAppearanceStyle) const
{
// Cache our original display.
style.setOriginalDisplay(style.display());
if (style.display() == DisplayType::Contents)
adjustDisplayContentsStyle(style);
if (style.display() != DisplayType::None && style.display() != DisplayType::Contents) {
if (m_element) {
// If we have a <td> that specifies a float property, in quirks mode we just drop the float
// property.
// Sites also commonly use display:inline/block on <td>s and <table>s. In quirks mode we force
// these tags to retain their display types.
if (m_document.inQuirksMode()) {
if (m_element->hasTagName(tdTag)) {
style.setDisplay(DisplayType::TableCell);
style.setFloating(Float::No);
} else if (is<HTMLTableElement>(*m_element))
style.setDisplay(style.isDisplayInlineType() ? DisplayType::InlineTable : DisplayType::Table);
}
if (m_element->hasTagName(tdTag) || m_element->hasTagName(thTag)) {
if (style.whiteSpace() == WhiteSpace::KHTMLNoWrap) {
// Figure out if we are really nowrapping or if we should just
// use normal instead. If the width of the cell is fixed, then
// we don't actually use WhiteSpace::NoWrap.
if (style.width().isFixed())
style.setWhiteSpace(WhiteSpace::Normal);
else
style.setWhiteSpace(WhiteSpace::NoWrap);
}
}
// Tables never support the -webkit-* values for text-align and will reset back to the default.
if (is<HTMLTableElement>(*m_element) && (style.textAlign() == TextAlignMode::WebKitLeft || style.textAlign() == TextAlignMode::WebKitCenter || style.textAlign() == TextAlignMode::WebKitRight))
style.setTextAlign(TextAlignMode::Start);
// Frames and framesets never honor position:relative or position:absolute. This is necessary to
// fix a crash where a site tries to position these objects. They also never honor display.
if (m_element->hasTagName(frameTag) || m_element->hasTagName(framesetTag)) {
style.setPosition(PositionType::Static);
style.setDisplay(DisplayType::Block);
}
// Ruby text does not support float or position. This might change with evolution of the specification.
if (m_element->hasTagName(rtTag)) {
style.setPosition(PositionType::Static);
style.setFloating(Float::No);
}
// User agents are expected to have a rule in their user agent stylesheet that matches th elements that have a parent
// node whose computed value for the 'text-align' property is its initial value, whose declaration block consists of
// just a single declaration that sets the 'text-align' property to the value 'center'.
// https://html.spec.whatwg.org/multipage/rendering.html#rendering
if (m_element->hasTagName(thTag) && !style.hasExplicitlySetTextAlign() && m_parentStyle.textAlign() == RenderStyle::initialTextAlign())
style.setTextAlign(TextAlignMode::Center);
if (m_element->hasTagName(legendTag))
style.setDisplay(DisplayType::Block);
}
// Absolute/fixed positioned elements, floating elements and the document element need block-like outside display.
if (style.hasOutOfFlowPosition() || style.isFloating() || (m_element && m_document.documentElement() == m_element))
style.setDisplay(equivalentBlockDisplay(style, m_document));
// FIXME: Don't support this mutation for pseudo styles like first-letter or first-line, since it's not completely
// clear how that should work.
if (style.display() == DisplayType::Inline && style.styleType() == PseudoId::None && style.writingMode() != m_parentStyle.writingMode())
style.setDisplay(DisplayType::InlineBlock);
// After performing the display mutation, check table rows. We do not honor position:relative or position:sticky on
// table rows or cells. This has been established for position:relative in CSS2.1 (and caused a crash in containingBlock()
// on some sites).
if ((style.display() == DisplayType::TableHeaderGroup || style.display() == DisplayType::TableRowGroup
|| style.display() == DisplayType::TableFooterGroup || style.display() == DisplayType::TableRow)
&& style.position() == PositionType::Relative)
style.setPosition(PositionType::Static);
// writing-mode does not apply to table row groups, table column groups, table rows, and table columns.
// FIXME: Table cells should be allowed to be perpendicular or flipped with respect to the table, though.
if (style.display() == DisplayType::TableColumn || style.display() == DisplayType::TableColumnGroup || style.display() == DisplayType::TableFooterGroup
|| style.display() == DisplayType::TableHeaderGroup || style.display() == DisplayType::TableRow || style.display() == DisplayType::TableRowGroup
|| style.display() == DisplayType::TableCell)
style.setWritingMode(m_parentStyle.writingMode());
// FIXME: Since we don't support block-flow on flexible boxes yet, disallow setting
// of block-flow to anything other than TopToBottomWritingMode.
// https://bugs.webkit.org/show_bug.cgi?id=46418 - Flexible box support.
if (style.writingMode() != TopToBottomWritingMode && (style.display() == DisplayType::Box || style.display() == DisplayType::InlineBox))
style.setWritingMode(TopToBottomWritingMode);
// https://www.w3.org/TR/css-display/#transformations
// "A parent with a grid or flex display value blockifies the box’s display type."
if (m_parentBoxStyle.isDisplayFlexibleOrGridBox()) {
style.setFloating(Float::No);
style.setDisplay(equivalentBlockDisplay(style, m_document));
}
}
// Make sure our z-index value is only applied if the object is positioned.
if (style.hasAutoSpecifiedZIndex() || (style.position() == PositionType::Static && !m_parentBoxStyle.isDisplayFlexibleOrGridBox()))
style.setHasAutoUsedZIndex();
else
style.setUsedZIndex(style.specifiedZIndex());
// Auto z-index becomes 0 for the root element and transparent objects. This prevents
// cases where objects that should be blended as a single unit end up with a non-transparent
// object wedged in between them. Auto z-index also becomes 0 for objects that specify transforms/masks/reflections.
if (style.hasAutoUsedZIndex()) {
if ((m_element && m_document.documentElement() == m_element)
|| style.opacity() < 1.0f
|| style.hasTransformRelatedProperty()
|| style.hasMask()
|| style.clipPath()
|| style.boxReflect()
|| style.hasFilter()
#if ENABLE(FILTERS_LEVEL_2)
|| style.hasBackdropFilter()
#endif
|| style.hasBlendMode()
|| style.hasIsolation()
|| style.position() == PositionType::Sticky
|| style.position() == PositionType::Fixed
|| style.willChangeCreatesStackingContext())
style.setUsedZIndex(0);
}
if (m_element) {
// Textarea considers overflow visible as auto.
if (is<HTMLTextAreaElement>(*m_element)) {
style.setOverflowX(style.overflowX() == Overflow::Visible ? Overflow::Auto : style.overflowX());
style.setOverflowY(style.overflowY() == Overflow::Visible ? Overflow::Auto : style.overflowY());
}
// Disallow -webkit-user-modify on :pseudo and ::pseudo elements.
if (!m_element->shadowPseudoId().isNull())
style.setUserModify(UserModify::ReadOnly);
if (is<HTMLMarqueeElement>(*m_element)) {
// For now, <marquee> requires an overflow clip to work properly.
style.setOverflowX(Overflow::Hidden);
style.setOverflowY(Overflow::Hidden);
bool isVertical = style.marqueeDirection() == MarqueeDirection::Up || style.marqueeDirection() == MarqueeDirection::Down;
// Make horizontal marquees not wrap.
if (!isVertical) {
style.setWhiteSpace(WhiteSpace::NoWrap);
style.setTextAlign(TextAlignMode::Start);
}
// Apparently this is the expected legacy behavior.
if (isVertical && style.height().isAuto())
style.setHeight(Length(200, Fixed));
}
}
if (doesNotInheritTextDecoration(style, m_element))
style.setTextDecorationsInEffect(style.textDecoration());
else
style.addToTextDecorationsInEffect(style.textDecoration());
// If either overflow value is not visible, change to auto.
if (style.overflowX() == Overflow::Visible && style.overflowY() != Overflow::Visible) {
// FIXME: Once we implement pagination controls, overflow-x should default to hidden
// if overflow-y is set to -webkit-paged-x or -webkit-page-y. For now, we'll let it
// default to auto so we can at least scroll through the pages.
style.setOverflowX(Overflow::Auto);
} else if (style.overflowY() == Overflow::Visible && style.overflowX() != Overflow::Visible)
style.setOverflowY(Overflow::Auto);
// Call setStylesForPaginationMode() if a pagination mode is set for any non-root elements. If these
// styles are specified on a root element, then they will be incorporated in
// Style::createForm_document.
if ((style.overflowY() == Overflow::PagedX || style.overflowY() == Overflow::PagedY) && !(m_element && (m_element->hasTagName(htmlTag) || m_element->hasTagName(bodyTag))))
style.setColumnStylesFromPaginationMode(WebCore::paginationModeForRenderStyle(style));
// Table rows, sections and the table itself will support overflow:hidden and will ignore scroll/auto.
// FIXME: Eventually table sections will support auto and scroll.
if (style.display() == DisplayType::Table || style.display() == DisplayType::InlineTable
|| style.display() == DisplayType::TableRowGroup || style.display() == DisplayType::TableRow) {
if (style.overflowX() != Overflow::Visible && style.overflowX() != Overflow::Hidden)
style.setOverflowX(Overflow::Visible);
if (style.overflowY() != Overflow::Visible && style.overflowY() != Overflow::Hidden)
style.setOverflowY(Overflow::Visible);
}
// Menulists should have visible overflow
if (style.appearance() == MenulistPart) {
style.setOverflowX(Overflow::Visible);
style.setOverflowY(Overflow::Visible);
}
#if ENABLE(OVERFLOW_SCROLLING_TOUCH)
// Touch overflow scrolling creates a stacking context.
if (style.hasAutoUsedZIndex() && style.useTouchOverflowScrolling() && (isScrollableOverflow(style.overflowX()) || isScrollableOverflow(style.overflowY())))
style.setUsedZIndex(0);
#endif
// Cull out any useless layers and also repeat patterns into additional layers.
style.adjustBackgroundLayers();
style.adjustMaskLayers();
// Do the same for animations and transitions.
style.adjustAnimations();
style.adjustTransitions();
// Important: Intrinsic margins get added to controls before the theme has adjusted the style, since the theme will
// alter fonts and heights/widths.
if (is<HTMLFormControlElement>(m_element) && style.computedFontPixelSize() >= 11) {
// Don't apply intrinsic margins to image buttons. The designer knows how big the images are,
// so we have to treat all image buttons as though they were explicitly sized.
if (!is<HTMLInputElement>(*m_element) || !downcast<HTMLInputElement>(*m_element).isImageButton())
addIntrinsicMargins(style);
}
// Let the theme also have a crack at adjusting the style.
if (style.hasAppearance())
RenderTheme::singleton().adjustStyle(style, m_element, userAgentAppearanceStyle);
// If we have first-letter pseudo style, do not share this style.
if (style.hasPseudoStyle(PseudoId::FirstLetter))
style.setUnique();
// FIXME: when dropping the -webkit prefix on transform-style, we should also have opacity < 1 cause flattening.
if (style.preserves3D() && (style.overflowX() != Overflow::Visible
|| style.overflowY() != Overflow::Visible
|| style.hasClip()
|| style.clipPath()
|| style.hasFilter()
#if ENABLE(FILTERS_LEVEL_2)
|| style.hasBackdropFilter()
#endif
|| style.hasBlendMode()))
style.setTransformStyle3D(TransformStyle3D::Flat);
if (is<SVGElement>(m_element))
adjustSVGElementStyle(style, downcast<SVGElement>(*m_element));
// If the inherited value of justify-items includes the 'legacy' keyword (plus 'left', 'right' or
// 'center'), 'legacy' computes to the the inherited value. Otherwise, 'auto' computes to 'normal'.
if (m_parentBoxStyle.justifyItems().positionType() == ItemPositionType::Legacy && style.justifyItems().position() == ItemPosition::Legacy)
style.setJustifyItems(m_parentBoxStyle.justifyItems());
#if ENABLE(POINTER_EVENTS)
style.setEffectiveTouchActions(computeEffectiveTouchActions(style, m_parentStyle.effectiveTouchActions()));
#endif
#if ENABLE(TEXT_AUTOSIZING)
if (m_element)
adjustForTextAutosizing(style, *m_element);
#endif
adjustForSiteSpecificQuirks(style);
}
static bool hasEffectiveDisplayNoneForDisplayContents(const Element& element)
{
// https://drafts.csswg.org/css-display-3/#unbox-html
static NeverDestroyed<HashSet<AtomString>> tagNames = [] {
static const HTMLQualifiedName* const tagList[] = {
&brTag.get(),
&wbrTag.get(),
&meterTag.get(),
&appletTag.get(),
&progressTag.get(),
&canvasTag.get(),
&embedTag.get(),
&objectTag.get(),
&audioTag.get(),
&iframeTag.get(),
&imgTag.get(),
&videoTag.get(),
&frameTag.get(),
&framesetTag.get(),
&inputTag.get(),
&textareaTag.get(),
&selectTag.get(),
};
HashSet<AtomString> set;
for (auto& name : tagList)
set.add(name->localName());
return set;
}();
// https://drafts.csswg.org/css-display-3/#unbox-svg
// FIXME: <g>, <use> and <tspan> have special (?) behavior for display:contents in the current draft spec.
if (is<SVGElement>(element))
return true;
#if ENABLE(MATHML)
// Not sure MathML code can handle it.
if (is<MathMLElement>(element))
return true;
#endif // ENABLE(MATHML)
if (!is<HTMLElement>(element))
return false;
return tagNames.get().contains(element.localName());
}
void Adjuster::adjustDisplayContentsStyle(RenderStyle& style) const
{
if (!m_element) {
if (style.styleType() != PseudoId::Before && style.styleType() != PseudoId::After)
style.setDisplay(DisplayType::None);
return;
}
if (m_document.documentElement() == m_element) {
style.setDisplay(DisplayType::Block);
return;
}
if (hasEffectiveDisplayNoneForDisplayContents(*m_element))
style.setDisplay(DisplayType::None);
}
void Adjuster::adjustSVGElementStyle(RenderStyle& style, const SVGElement& svgElement)
{
// Only the root <svg> element in an SVG document fragment tree honors css position
auto isPositioningAllowed = svgElement.hasTagName(SVGNames::svgTag) && svgElement.parentNode() && !svgElement.parentNode()->isSVGElement() && !svgElement.correspondingElement();
if (!isPositioningAllowed)
style.setPosition(RenderStyle::initialPosition());
// RenderSVGRoot handles zooming for the whole SVG subtree, so foreignObject content should
// not be scaled again.
if (svgElement.hasTagName(SVGNames::foreignObjectTag))
style.setEffectiveZoom(RenderStyle::initialZoom());
// SVG text layout code expects us to be a block-level style element.
if ((svgElement.hasTagName(SVGNames::foreignObjectTag) || svgElement.hasTagName(SVGNames::textTag)) && style.isDisplayInlineType())
style.setDisplay(DisplayType::Block);
}
void Adjuster::adjustAnimatedStyle(RenderStyle& style, const RenderStyle* parentBoxStyle, OptionSet<AnimationImpact> impact)
{
// Set an explicit used z-index in two cases:
// 1. When the element respects z-index, and the style has an explicit z-index set (for example, the animation
// itself may animate z-index).
// 2. When we want the stacking context side-effets of explicit z-index, via forceStackingContext.
// It's important to not clobber an existing used z-index, since an earlier animation may have set it, but we
// may still need to update the used z-index value from the specified value.
bool elementRespectsZIndex = style.position() != PositionType::Static || (parentBoxStyle && parentBoxStyle->isDisplayFlexibleOrGridBox());
if (elementRespectsZIndex && !style.hasAutoSpecifiedZIndex())
style.setUsedZIndex(style.specifiedZIndex());
else if (impact.contains(AnimationImpact::ForcesStackingContext))
style.setUsedZIndex(0);
}
void Adjuster::adjustForSiteSpecificQuirks(RenderStyle& style) const
{
if (m_document.quirks().needsGMailOverflowScrollQuirk() && m_element) {
// This turns sidebar scrollable without mouse move event.
static NeverDestroyed<AtomString> roleValue("navigation", AtomString::ConstructFromLiteral);
if (style.overflowY() == Overflow::Hidden && m_element->attributeWithoutSynchronization(roleAttr) == roleValue)
style.setOverflowY(Overflow::Auto);
}
if (m_document.quirks().needsYouTubeOverflowScrollQuirk() && m_element) {
// This turns sidebar scrollable without hover.
static NeverDestroyed<AtomString> idValue("guide-inner-content", AtomString::ConstructFromLiteral);
if (style.overflowY() == Overflow::Hidden && m_element->idForStyleResolution() == idValue)
style.setOverflowY(Overflow::Auto);
}
}
#if ENABLE(TEXT_AUTOSIZING)
static bool hasTextChild(const Element& element)
{
for (auto* child = element.firstChild(); child; child = child->nextSibling()) {
if (is<Text>(child))
return true;
}
return false;
}
bool Adjuster::adjustForTextAutosizing(RenderStyle& style, const Element& element)
{
auto& document = element.document();
if (!document.settings().textAutosizingEnabled() || !document.settings().textAutosizingUsesIdempotentMode())
return false;
AutosizeStatus::updateStatus(style);
if (style.textSizeAdjust().isNone())
return false;
float initialScale = document.page() ? document.page()->initialScale() : 1;
auto adjustLineHeightIfNeeded = [&](auto computedFontSize) {
auto lineHeight = style.specifiedLineHeight();
constexpr static unsigned eligibleFontSize = 12;
if (computedFontSize * initialScale >= eligibleFontSize)
return;
constexpr static float boostFactor = 1.25;
auto minimumLineHeight = boostFactor * computedFontSize;
if (!lineHeight.isFixed() || lineHeight.value() >= minimumLineHeight)
return;
if (AutosizeStatus::probablyContainsASmallFixedNumberOfLines(style))
return;
style.setLineHeight({ minimumLineHeight, Fixed });
};
auto fontDescription = style.fontDescription();
auto initialComputedFontSize = fontDescription.computedSize();
auto specifiedFontSize = fontDescription.specifiedSize();
bool isCandidate = style.isIdempotentTextAutosizingCandidate();
if (!isCandidate && WTF::areEssentiallyEqual(initialComputedFontSize, specifiedFontSize))
return false;
auto adjustedFontSize = AutosizeStatus::idempotentTextSize(fontDescription.specifiedSize(), initialScale);
if (isCandidate && WTF::areEssentiallyEqual(initialComputedFontSize, adjustedFontSize))
return false;
if (!hasTextChild(element))
return false;
fontDescription.setComputedSize(isCandidate ? adjustedFontSize : specifiedFontSize);
style.setFontDescription(WTFMove(fontDescription));
style.fontCascade().update(&document.fontSelector());
// FIXME: We should restore computed line height to its original value in the case where the element is not
// an idempotent text autosizing candidate; otherwise, if an element that is a text autosizing candidate contains
// children which are not autosized, the non-autosized content will end up with a boosted line height.
if (isCandidate)
adjustLineHeightIfNeeded(adjustedFontSize);
return true;
}
#endif
}
}