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/*
* Copyright (C) 2014-2021 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 "LayoutIntegrationLineIterator.h"
#include "LayoutIntegrationRunIterator.h"
#include "LegacyInlineTextBox.h"
#include "LegacyRootInlineBox.h"
#include "RenderInline.h"
#include "TextUnderlineOffset.h"
namespace WebCore {
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 void minLogicalTopForTextDecorationLine(const LayoutIntegration::LineIterator& line, float& minLogicalTop, const RenderElement* decorationRenderer, OptionSet<TextDecoration> textDecoration)
{
for (auto run = line.firstRun(); run; run.traverseNextOnLine()) {
if (run->renderer().isOutOfFlowPositioned())
continue; // Positioned placeholders don't affect calculations.
if (!(run->style().textDecorationsInEffect() & textDecoration))
continue; // If the text decoration isn't in effect on the child, then it must be outside of |decorationRenderer|'s hierarchy.
if (decorationRenderer && decorationRenderer->isRenderInline() && !isAncestorAndWithinBlock(downcast<RenderInline>(*decorationRenderer), &run->renderer()))
continue;
if (run->isText() || run->style().textDecorationSkip().isEmpty())
minLogicalTop = std::min<float>(minLogicalTop, run->logicalTop());
}
}
static void maxLogicalBottomForTextDecorationLine(const LayoutIntegration::LineIterator& line, float& maxLogicalBottom, const RenderElement* decorationRenderer, OptionSet<TextDecoration> textDecoration)
{
for (auto run = line.firstRun(); run; run.traverseNextOnLine()) {
if (run->renderer().isOutOfFlowPositioned())
continue; // Positioned placeholders don't affect calculations.
if (!(run->style().textDecorationsInEffect() & textDecoration))
continue; // If the text decoration isn't in effect on the child, then it must be outside of |decorationRenderer|'s hierarchy.
if (decorationRenderer && decorationRenderer->isRenderInline() && !isAncestorAndWithinBlock(downcast<RenderInline>(*decorationRenderer), &run->renderer()))
continue;
if (run->isText() || run->style().textDecorationSkip().isEmpty())
maxLogicalBottom = std::max<float>(maxLogicalBottom, run->logicalBottom());
}
}
static const RenderElement* enclosingRendererWithTextDecoration(const RenderText& renderer, OptionSet<TextDecoration> textDecoration, bool firstLine)
{
const RenderElement* current = renderer.parent();
do {
if (current->isRenderBlock())
return current;
if (!current->isRenderInline() || current->isRubyText())
return nullptr;
const RenderStyle& styleToUse = firstLine ? current->firstLineStyle() : current->style();
if (styleToUse.textDecoration() & textDecoration)
return current;
current = current->parent();
} while (current && (!current->element() || (!is<HTMLAnchorElement>(*current->element()) && !current->element()->hasTagName(HTMLNames::fontTag))));
return current;
}
float computeUnderlineOffset(TextUnderlinePosition underlinePosition, TextUnderlineOffset underlineOffset, const FontMetrics& fontMetrics, const LayoutIntegration::TextRunIterator& textRun, float defaultGap)
{
// This represents the gap between the baseline and the closest edge of the underline.
float gap = std::max<int>(1, std::ceil(defaultGap / 2.0f));
// 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 TextUnderlinePosition::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 resolvedUnderlinePosition = underlinePosition;
if (resolvedUnderlinePosition == TextUnderlinePosition::Auto && underlineOffset.isAuto()) {
if (textRun)
resolvedUnderlinePosition = textRun.line()->baselineType() == IdeographicBaseline ? TextUnderlinePosition::Under : TextUnderlinePosition::Auto;
else
resolvedUnderlinePosition = TextUnderlinePosition::Auto;
}
switch (resolvedUnderlinePosition) {
case TextUnderlinePosition::Auto:
if (underlineOffset.isAuto())
return fontMetrics.ascent() + gap;
return fontMetrics.ascent() + underlineOffset.lengthValue();
case TextUnderlinePosition::FromFont:
return fontMetrics.ascent() + fontMetrics.underlinePosition() + underlineOffset.lengthOr(0);
case TextUnderlinePosition::Under: {
ASSERT(textRun);
// Position underline relative to the bottom edge of the lowest element's content box.
auto line = textRun.line();
auto* decorationRenderer = enclosingRendererWithTextDecoration(textRun->renderer(), TextDecoration::Underline, line.isFirst());
float offset;
if (textRun->renderer().style().isFlippedLinesWritingMode()) {
offset = textRun->logicalTop();
minLogicalTopForTextDecorationLine(line, offset, decorationRenderer, TextDecoration::Underline);
offset = textRun->logicalTop() - offset;
} else {
offset = textRun->logicalBottom();
maxLogicalBottomForTextDecorationLine(line, offset, decorationRenderer, TextDecoration::Underline);
offset -= textRun->logicalBottom();
}
auto desiredOffset = textRun->logicalHeight() + gap + std::max(offset, 0.0f) + underlineOffset.lengthOr(0);
return std::max<float>(desiredOffset, fontMetrics.ascent());
}
}
ASSERT_NOT_REACHED();
return fontMetrics.ascent() + gap;
}
WavyStrokeParameters getWavyStrokeParameters(float fontSize)
{
WavyStrokeParameters result;
// More information is in the WavyStrokeParameters definition.
result.controlPointDistance = fontSize * 1.5 / 16;
result.step = fontSize / 4.5;
return result;
}
GlyphOverflow visualOverflowForDecorations(const RenderStyle& lineStyle, const LayoutIntegration::TextRunIterator& textRun)
{
ASSERT(!textRun || textRun->style() == lineStyle);
auto decoration = lineStyle.textDecorationsInEffect();
if (decoration.isEmpty())
return GlyphOverflow();
float strokeThickness = lineStyle.textDecorationThickness().resolve(lineStyle.computedFontSize(), lineStyle.fontMetrics());
WavyStrokeParameters wavyStrokeParameters;
float wavyOffset = 0;
TextDecorationStyle decorationStyle = lineStyle.textDecorationStyle();
float height = lineStyle.fontCascade().fontMetrics().floatHeight();
GlyphOverflow overflowResult;
if (decorationStyle == TextDecorationStyle::Wavy) {
wavyStrokeParameters = getWavyStrokeParameters(lineStyle.computedFontPixelSize());
wavyOffset = wavyOffsetFromDecoration();
overflowResult.left = strokeThickness;
overflowResult.right = strokeThickness;
}
// These metrics must match where underlines get drawn.
// FIXME: Share the code in TextDecorationPainter::paintTextDecoration() so we can just query it for the painted geometry.
if (decoration & TextDecoration::Underline) {
// Compensate for the integral ceiling in GraphicsContext::computeLineBoundsAndAntialiasingModeForText()
int underlineOffset = 1;
float textDecorationBaseFontSize = 16;
auto defaultGap = lineStyle.computedFontSize() / textDecorationBaseFontSize;
underlineOffset += computeUnderlineOffset(lineStyle.textUnderlinePosition(), lineStyle.textUnderlineOffset(), lineStyle.fontMetrics(), textRun, defaultGap);
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 & TextDecoration::Overline) {
FloatRect rect(FloatPoint(), FloatSize(1, strokeThickness));
float autoTextDecorationThickness = TextDecorationThickness::createWithAuto().resolve(lineStyle.computedFontSize(), lineStyle.fontMetrics());
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 & TextDecoration::LineThrough) {
FloatRect rect(FloatPoint(), FloatSize(1, strokeThickness));
float autoTextDecorationThickness = TextDecorationThickness::createWithAuto().resolve(lineStyle.computedFontSize(), lineStyle.fontMetrics());
auto center = 2 * lineStyle.fontMetrics().floatAscent() / 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;
}
}
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