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/*
* Copyright (C) 2014-2023 Apple Inc. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
* OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include "config.h"
#include "InlineTextBoxStyle.h"
#include "FontCascade.h"
#include "HTMLAnchorElement.h"
#include "HTMLNames.h"
#include "InlineIteratorBoxInlines.h"
#include "InlineIteratorInlineBox.h"
#include "InlineIteratorTextBox.h"
#include "RenderBoxModelObjectInlines.h"
#include "RenderInline.h"
namespace WebCore {
struct UnderlineOffsetArguments {
const RenderStyle& lineStyle;
std::optional<TextUnderlinePositionUnder> textUnderlinePositionUnder { };
};
static bool isAncestorAndWithinBlock(const RenderInline& ancestor, const RenderObject* child)
{
const RenderObject* object = child;
while (object && (!object->isRenderBlock() || object->isInline())) {
if (object == &ancestor)
return true;
object = object->parent();
}
return false;
}
static float minLogicalTopForTextDecorationLineUnder(const InlineIterator::LineBoxIterator& lineBox, float textRunLogicalTop, const RenderElement& decoratingBoxRendererForUnderline)
{
auto minLogicalTop = textRunLogicalTop;
for (auto run = lineBox->lineLeftmostLeafBox(); run; run.traverseLineRightwardOnLine()) {
if (run->renderer().isOutOfFlowPositioned())
continue; // Positioned placeholders don't affect calculations.
if (!run->style().textDecorationsInEffect().contains(TextDecorationLine::Underline))
continue; // If the text decoration isn't in effect on the child, then it must be outside of |decoratingBoxRendererForUnderline|'s hierarchy.
if (auto* renderInline = dynamicDowncast<RenderInline>(decoratingBoxRendererForUnderline); renderInline && !isAncestorAndWithinBlock(*renderInline, &run->renderer()))
continue;
if (run->isText() || run->style().textDecorationSkipInk() == TextDecorationSkipInk::None)
minLogicalTop = std::min<float>(minLogicalTop, run->logicalTop());
}
return minLogicalTop;
}
static float maxLogicalBottomForTextDecorationLineUnder(const InlineIterator::LineBoxIterator& lineBox, float textRunLogicalBottom, const RenderElement& decoratingBoxRendererForUnderline)
{
auto maxLogicalBottom = textRunLogicalBottom;
for (auto run = lineBox->lineLeftmostLeafBox(); run; run.traverseLineRightwardOnLine()) {
if (run->renderer().isOutOfFlowPositioned())
continue; // Positioned placeholders don't affect calculations.
if (!run->style().textDecorationsInEffect().contains(TextDecorationLine::Underline))
continue; // If the text decoration isn't in effect on the child, then it must be outside of |decoratingBoxRendererForUnderline|'s hierarchy.
if (auto* renderInline = dynamicDowncast<RenderInline>(decoratingBoxRendererForUnderline); renderInline && !isAncestorAndWithinBlock(*renderInline, &run->renderer()))
continue;
if (run->isText() || run->style().textDecorationSkipInk() == TextDecorationSkipInk::None)
maxLogicalBottom = std::max<float>(maxLogicalBottom, run->logicalBottom());
}
return maxLogicalBottom;
}
static const RenderElement* enclosingRendererWithTextDecoration(const RenderText& renderer)
{
for (auto* ancestor = renderer.parent(); ancestor; ancestor = ancestor->parent()) {
if (ancestor->isRenderBlock())
return ancestor;
if (!ancestor->isRenderInline()) {
// We should always find either the block container or an inline box ancestor inbetween.
return nullptr;
}
auto isDecoratingInlineBox = [&] {
if (ancestor->element() && (is<HTMLAnchorElement>(*ancestor->element()) || ancestor->element()->hasTagName(HTMLNames::fontTag))) {
// <font> and <a> are always considered decorating boxes.
return true;
}
return ancestor->style().textDecorationLine().contains(TextDecorationLine::Underline);
};
if (isDecoratingInlineBox())
return ancestor;
}
return nullptr;
}
static float boxOffsetFromBottomMost(const InlineIterator::LineBoxIterator& lineBox, const RenderElement& decoratingInlineBoxRenderer, float boxLogicalTop, float boxLogicalBottom)
{
if (decoratingInlineBoxRenderer.writingMode().isLineInverted())
return boxLogicalTop - minLogicalTopForTextDecorationLineUnder(lineBox, boxLogicalTop, decoratingInlineBoxRenderer);
return maxLogicalBottomForTextDecorationLineUnder(lineBox, boxLogicalBottom, decoratingInlineBoxRenderer) - boxLogicalBottom;
}
static float textRunOffsetFromBottomMost(const InlineIterator::LineBoxIterator& lineBox, const RenderText& renderer, float textBoxLogicalTop, float textBoxLogicalBottom)
{
auto* decoratingBoxRendererForUnderline = enclosingRendererWithTextDecoration(renderer);
if (!decoratingBoxRendererForUnderline)
return 0.f;
return boxOffsetFromBottomMost(lineBox, *decoratingBoxRendererForUnderline, textBoxLogicalTop, textBoxLogicalBottom);
}
static inline float defaultGap(const RenderStyle& style)
{
// This represents the gap between the baseline and the closest edge of the underline.
const float textDecorationBaseFontSize = 16.f;
return std::max(1.f, ceilf(style.computedFontSize() / textDecorationBaseFontSize / 2.f));
}
static float computedUnderlineOffset(const UnderlineOffsetArguments& context)
{
// FIXME: The code for visual overflow detection passes in a null inline text box. This means it is now
// broken for the case where auto needs to behave like "under".
// According to the specification `text-underline-position: auto` should avoid drawing through glyphs in
// scripts where it would not be appropriate (e.g., ideographs).
// Strictly speaking this can occur whenever the line contains ideographs
// even if it is horizontal, but detecting this has performance implications. For now we only work with
// vertical text, since we already determined the baseline type to be ideographic in that case.
auto& styleToUse = context.lineStyle;
auto& fontMetrics = styleToUse.metricsOfPrimaryFont();
auto underlineOffset = 0.f;
auto textUnderlinePosition = styleToUse.textUnderlinePosition();
if (isAlignedForUnder(styleToUse)) {
ASSERT(context.textUnderlinePositionUnder);
// FIXME: This needs to be flipped for sideways-lr.
if (textUnderlinePosition.contains(TextUnderlinePosition::Right)) {
ASSERT(!textUnderlinePosition.contains(TextUnderlinePosition::Left));
// In vertical typographic modes, the underline is aligned as for under, except it is always aligned to the right edge of the text.
underlineOffset = 0.f - (styleToUse.textUnderlineOffset().resolve(styleToUse.computedFontSize()) + defaultGap(styleToUse));
} else {
// Position underline relative to the bottom edge of the lowest element's content box.
auto desiredOffset = context.textUnderlinePositionUnder->textRunLogicalHeight + std::max(context.textUnderlinePositionUnder->textRunOffsetFromBottomMost, 0.f);
desiredOffset += styleToUse.textUnderlineOffset().resolve(styleToUse.computedFontSize()) + defaultGap(styleToUse);
underlineOffset = std::max<float>(desiredOffset, fontMetrics.intAscent());
}
} else if (textUnderlinePosition.contains(TextUnderlinePosition::FromFont)) {
ASSERT(!textUnderlinePosition.contains(TextUnderlinePosition::Under));
underlineOffset = fontMetrics.intAscent() + fontMetrics.underlinePosition().value_or(0) + styleToUse.textUnderlineOffset().resolve(styleToUse.computedFontSize());
} else
underlineOffset = fontMetrics.intAscent() + styleToUse.textUnderlineOffset().resolve(styleToUse.computedFontSize(), defaultGap(styleToUse));
return underlineOffset;
}
WavyStrokeParameters wavyStrokeParameters(float fontSize)
{
WavyStrokeParameters result;
// More information is in the WavyStrokeParameters definition.
result.controlPointDistance = fontSize * 1.5 / 16;
result.step = fontSize / 4.5;
return result;
}
static GlyphOverflow computedInkOverflowForDecorations(const RenderStyle& lineStyle, std::optional<float> underlineOffset)
{
// Compensate for the integral ceiling in GraphicsContext::computeLineBoundsAndAntialiasingModeForText()
if (underlineOffset)
*underlineOffset += *underlineOffset >= 0 ? 1 : -1;
auto decoration = lineStyle.textDecorationsInEffect();
if (decoration.isEmpty())
return GlyphOverflow();
float strokeThickness = lineStyle.textDecorationThickness().resolve(lineStyle.computedFontSize(), lineStyle.metricsOfPrimaryFont());
WavyStrokeParameters wavyStrokeParameters;
float wavyOffset = 0;
TextDecorationStyle decorationStyle = lineStyle.textDecorationStyle();
float height = lineStyle.fontCascade().metricsOfPrimaryFont().height();
GlyphOverflow overflowResult;
if (decorationStyle == TextDecorationStyle::Wavy) {
wavyStrokeParameters = WebCore::wavyStrokeParameters(lineStyle.computedFontSize());
wavyOffset = wavyOffsetFromDecoration();
overflowResult.left = strokeThickness;
overflowResult.right = strokeThickness;
}
// These metrics must match where underlines get drawn.
// FIXME: Share the code in TextDecorationPainter::paintBackgroundDecorations() so we can just query it for the painted geometry.
if (decoration & TextDecorationLine::Underline) {
ASSERT(underlineOffset);
if (decorationStyle == TextDecorationStyle::Wavy) {
overflowResult.extendBottom(*underlineOffset + wavyOffset + wavyStrokeParameters.controlPointDistance + strokeThickness - height);
overflowResult.extendTop(-(*underlineOffset + wavyOffset - wavyStrokeParameters.controlPointDistance - strokeThickness));
} else {
overflowResult.extendBottom(*underlineOffset + strokeThickness - height);
overflowResult.extendTop(-*underlineOffset);
}
}
if (decoration & TextDecorationLine::Overline) {
FloatRect rect(FloatPoint(), FloatSize(1, strokeThickness));
float autoTextDecorationThickness = TextDecorationThickness::createWithAuto().resolve(lineStyle.computedFontSize(), lineStyle.metricsOfPrimaryFont());
rect.move(0, autoTextDecorationThickness - strokeThickness - wavyOffset);
if (decorationStyle == TextDecorationStyle::Wavy) {
FloatBoxExtent wavyExpansion;
wavyExpansion.setTop(wavyStrokeParameters.controlPointDistance);
wavyExpansion.setBottom(wavyStrokeParameters.controlPointDistance);
rect.expand(wavyExpansion);
}
overflowResult.extendTop(-rect.y());
overflowResult.extendBottom(rect.maxY() - height);
}
if (decoration & TextDecorationLine::LineThrough) {
FloatRect rect(FloatPoint(), FloatSize(1, strokeThickness));
float autoTextDecorationThickness = TextDecorationThickness::createWithAuto().resolve(lineStyle.computedFontSize(), lineStyle.metricsOfPrimaryFont());
auto center = 2 * lineStyle.metricsOfPrimaryFont().ascent() / 3 + autoTextDecorationThickness / 2;
rect.move(0, center - strokeThickness / 2);
if (decorationStyle == TextDecorationStyle::Wavy) {
FloatBoxExtent wavyExpansion;
wavyExpansion.setTop(wavyStrokeParameters.controlPointDistance);
wavyExpansion.setBottom(wavyStrokeParameters.controlPointDistance);
rect.expand(wavyExpansion);
}
overflowResult.extendTop(-rect.y());
overflowResult.extendBottom(rect.maxY() - height);
}
return overflowResult;
}
bool isAlignedForUnder(const RenderStyle& decoratingBoxStyle)
{
auto underlinePosition = decoratingBoxStyle.textUnderlinePosition();
if (underlinePosition.contains(TextUnderlinePosition::Under))
return true;
if (!decoratingBoxStyle.writingMode().isVerticalTypographic()
|| decoratingBoxStyle.writingMode().isSidewaysOrientation())
return false;
if (underlinePosition.contains(TextUnderlinePosition::Left) || underlinePosition.contains(TextUnderlinePosition::Right)) {
// In vertical typographic modes, the underline is aligned as for under for 'left' and 'right'.
return true;
}
// When left/right support is not enabled.
// FIXME: The offset check is mostly about visual overflow, consider splitting out.
return underlinePosition.isEmpty() && decoratingBoxStyle.textUnderlineOffset().isAuto();
}
GlyphOverflow inkOverflowForDecorations(const InlineIterator::LineBoxIterator& lineBox, const RenderText& renderer, float textBoxLogicalTop, float textBoxLogicalBottom)
{
auto& style = lineBox->isFirst() ? renderer.firstLineStyle() : renderer.style();
auto textUnderlinePositionUnder = std::optional<TextUnderlinePositionUnder> { };
if (isAlignedForUnder(style)) {
auto textRunOffset = textRunOffsetFromBottomMost(lineBox, renderer, textBoxLogicalTop, textBoxLogicalBottom);
textUnderlinePositionUnder = TextUnderlinePositionUnder { textBoxLogicalBottom - textBoxLogicalTop, textRunOffset };
}
auto underlineOffset = style.textDecorationsInEffect().contains(TextDecorationLine::Underline)
? std::make_optional(computedUnderlineOffset({ style, textUnderlinePositionUnder }))
: std::nullopt;
return computedInkOverflowForDecorations(style, underlineOffset);
}
GlyphOverflow inkOverflowForDecorations(const RenderStyle& style, TextUnderlinePositionUnder textUnderlinePositionUnder)
{
auto underlineOffset = style.textDecorationsInEffect().contains(TextDecorationLine::Underline)
? std::make_optional(computedUnderlineOffset({ style, textUnderlinePositionUnder }))
: std::nullopt;
return computedInkOverflowForDecorations(style, underlineOffset);
}
GlyphOverflow inkOverflowForDecorations(const RenderStyle& style)
{
auto underlineOffset = style.textDecorationsInEffect().contains(TextDecorationLine::Underline)
? std::make_optional(computedUnderlineOffset({ style, { } }))
: std::nullopt;
return computedInkOverflowForDecorations(style, underlineOffset);
}
static inline float inlineBoxContentBoxHeight(const InlineIterator::InlineBox& inlineBox)
{
auto contentBoxHeight = inlineBox.logicalHeight();
if (!inlineBox.isRootInlineBox())
contentBoxHeight -= (inlineBox.renderer().borderAndPaddingBefore() + inlineBox.renderer().borderAndPaddingAfter());
return contentBoxHeight;
}
float underlineOffsetForTextBoxPainting(const InlineIterator::InlineBox& inlineBox, const RenderStyle& style)
{
if (!isAlignedForUnder(style))
return computedUnderlineOffset({ style, { } });
auto textRunOffset = boxOffsetFromBottomMost(inlineBox.lineBox(), inlineBox.renderer(), inlineBox.logicalTop(), inlineBox.logicalBottom());
return computedUnderlineOffset({ style, TextUnderlinePositionUnder { inlineBoxContentBoxHeight(inlineBox), textRunOffset } });
}
float overlineOffsetForTextBoxPainting(const InlineIterator::InlineBox& inlineBox, const RenderStyle& style)
{
if (!style.writingMode().isVerticalTypographic())
return { };
// If 'right' causes the underline to be drawn on the "over" side of the text, then an overline also switches sides and is drawn on the "under" side.
auto underlinePosition = style.textUnderlinePosition();
return underlinePosition.contains(TextUnderlinePosition::Right)
? inlineBoxContentBoxHeight(inlineBox) + defaultGap(style)
: (0.f - defaultGap(style));
}
}
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