blob: 77870a371571711a9c97daa8c820b5f6639cf583 [file] [log] [blame]
/*
* (C) 1999 Lars Knoll (knoll@kde.org)
* (C) 2000 Dirk Mueller (mueller@kde.org)
* Copyright (C) 2004-2017 Apple Inc. All rights reserved.
*
* 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 "TextDecorationPainter.h"
#include "FilterOperations.h"
#include "FontCascade.h"
#include "GraphicsContext.h"
#include "HTMLAnchorElement.h"
#include "HTMLFontElement.h"
#include "InlineTextBoxStyle.h"
#include "RenderBlock.h"
#include "RenderStyle.h"
#include "RenderText.h"
#include "ShadowData.h"
#include "TextRun.h"
namespace WebCore {
static void adjustStepToDecorationLength(float& step, float& controlPointDistance, float length)
{
ASSERT(step > 0);
if (length <= 0)
return;
unsigned stepCount = static_cast<unsigned>(length / step);
// Each Bezier curve starts at the same pixel that the previous one
// ended. We need to subtract (stepCount - 1) pixels when calculating the
// length covered to account for that.
float uncoveredLength = length - (stepCount * step - (stepCount - 1));
float adjustment = uncoveredLength / stepCount;
step += adjustment;
controlPointDistance += adjustment;
}
/*
* Draw one cubic Bezier curve and repeat the same pattern long the the decoration's axis.
* The start point (p1), controlPoint1, controlPoint2 and end point (p2) of the Bezier curve
* form a diamond shape:
*
* step
* |-----------|
*
* controlPoint1
* +
*
*
* . .
* . .
* . .
* (x1, y1) p1 + . + p2 (x2, y2) - <--- Decoration's axis
* . . |
* . . |
* . . | controlPointDistance
* |
* |
* + -
* controlPoint2
*
* |-----------|
* step
*/
static void strokeWavyTextDecoration(GraphicsContext& context, const FloatRect& rect, float fontSize)
{
FloatPoint p1 = rect.minXMinYCorner();
FloatPoint p2 = rect.maxXMinYCorner();
context.adjustLineToPixelBoundaries(p1, p2, rect.height(), context.strokeStyle());
Path path;
path.moveTo(p1);
auto wavyStrokeParameters = getWavyStrokeParameters(fontSize);
ASSERT(p1.y() == p2.y());
float yAxis = p1.y();
float x1 = std::min(p1.x(), p2.x());
float x2 = std::max(p1.x(), p2.x());
adjustStepToDecorationLength(wavyStrokeParameters.step, wavyStrokeParameters.controlPointDistance, x2 - x1);
FloatPoint controlPoint1(0, yAxis + wavyStrokeParameters.controlPointDistance);
FloatPoint controlPoint2(0, yAxis - wavyStrokeParameters.controlPointDistance);
for (float x = x1; x + 2 * wavyStrokeParameters.step <= x2;) {
controlPoint1.setX(x + wavyStrokeParameters.step);
controlPoint2.setX(x + wavyStrokeParameters.step);
x += 2 * wavyStrokeParameters.step;
path.addBezierCurveTo(controlPoint1, controlPoint2, FloatPoint(x, yAxis));
}
context.setShouldAntialias(true);
auto strokeThickness = context.strokeThickness();
context.setStrokeThickness(rect.height());
context.strokePath(path);
context.setStrokeThickness(strokeThickness);
}
static bool compareTuples(std::pair<float, float> l, std::pair<float, float> r)
{
return l.first < r.first;
}
static DashArray translateIntersectionPointsToSkipInkBoundaries(const DashArray& intersections, float dilationAmount, float totalWidth)
{
ASSERT(!(intersections.size() % 2));
// Step 1: Make pairs so we can sort based on range starting-point. We dilate the ranges in this step as well.
Vector<std::pair<float, float>> tuples;
for (auto i = intersections.begin(); i != intersections.end(); i++, i++)
tuples.append(std::make_pair(*i - dilationAmount, *(i + 1) + dilationAmount));
std::sort(tuples.begin(), tuples.end(), &compareTuples);
// Step 2: Deal with intersecting ranges.
Vector<std::pair<float, float>> intermediateTuples;
if (tuples.size() >= 2) {
intermediateTuples.append(*tuples.begin());
for (auto i = tuples.begin() + 1; i != tuples.end(); i++) {
float& firstEnd = intermediateTuples.last().second;
float secondStart = i->first;
float secondEnd = i->second;
if (secondStart <= firstEnd && secondEnd <= firstEnd) {
// Ignore this range completely
} else if (secondStart <= firstEnd)
firstEnd = secondEnd;
else
intermediateTuples.append(*i);
}
} else
intermediateTuples = tuples;
// Step 3: Output the space between the ranges, but only if the space warrants an underline.
float previous = 0;
DashArray result;
for (const auto& tuple : intermediateTuples) {
if (tuple.first - previous > dilationAmount) {
result.append(previous);
result.append(tuple.first);
}
previous = tuple.second;
}
if (totalWidth - previous > dilationAmount) {
result.append(previous);
result.append(totalWidth);
}
return result;
}
static StrokeStyle textDecorationStyleToStrokeStyle(TextDecorationStyle decorationStyle)
{
StrokeStyle strokeStyle = SolidStroke;
switch (decorationStyle) {
case TextDecorationStyle::Solid:
strokeStyle = SolidStroke;
break;
case TextDecorationStyle::Double:
strokeStyle = DoubleStroke;
break;
case TextDecorationStyle::Dotted:
strokeStyle = DottedStroke;
break;
case TextDecorationStyle::Dashed:
strokeStyle = DashedStroke;
break;
case TextDecorationStyle::Wavy:
strokeStyle = WavyStroke;
break;
}
return strokeStyle;
}
bool TextDecorationPainter::Styles::operator==(const Styles& other) const
{
return underlineColor == other.underlineColor && overlineColor == other.overlineColor && linethroughColor == other.linethroughColor
&& underlineStyle == other.underlineStyle && overlineStyle == other.overlineStyle && linethroughStyle == other.linethroughStyle;
}
TextDecorationPainter::TextDecorationPainter(GraphicsContext& context, OptionSet<TextDecoration> decorations, const RenderText& renderer, bool isFirstLine, const FontCascade& font, Optional<Styles> styles)
: m_context { context }
, m_decorations { decorations }
, m_wavyOffset { wavyOffsetFromDecoration() }
, m_isPrinting { renderer.document().printing() }
, m_font { font }
, m_styles { styles ? *WTFMove(styles) : stylesForRenderer(renderer, decorations, isFirstLine, PseudoId::None) }
, m_lineStyle { isFirstLine ? renderer.firstLineStyle() : renderer.style() }
{
}
void TextDecorationPainter::paintTextDecoration(const TextRun& textRun, const FloatPoint& textOrigin, const FloatPoint& boxOrigin)
{
const auto& fontMetrics = m_lineStyle.fontMetrics();
float textDecorationThickness = m_lineStyle.textDecorationThickness().resolve(m_lineStyle.computedFontSize(), fontMetrics);
FloatPoint localOrigin = boxOrigin;
auto paintDecoration = [&] (TextDecoration decoration, TextDecorationStyle style, const Color& color, const FloatRect& rect) {
m_context.setStrokeColor(color);
auto strokeStyle = textDecorationStyleToStrokeStyle(style);
if (style == TextDecorationStyle::Wavy)
strokeWavyTextDecoration(m_context, rect, m_lineStyle.computedFontPixelSize());
else if (decoration == TextDecoration::Underline || decoration == TextDecoration::Overline) {
if ((m_lineStyle.textDecorationSkip() == TextDecorationSkip::Ink || m_lineStyle.textDecorationSkip() == TextDecorationSkip::Auto) && m_isHorizontal) {
if (!m_context.paintingDisabled()) {
FloatRect underlineBoundingBox = m_context.computeUnderlineBoundsForText(rect, m_isPrinting);
DashArray intersections = m_font.dashesForIntersectionsWithRect(textRun, textOrigin, underlineBoundingBox);
DashArray boundaries = translateIntersectionPointsToSkipInkBoundaries(intersections, underlineBoundingBox.height(), rect.width());
ASSERT(!(boundaries.size() % 2));
// We don't use underlineBoundingBox here because drawLinesForText() will run computeUnderlineBoundsForText() internally.
m_context.drawLinesForText(rect.location(), rect.height(), boundaries, m_isPrinting, style == TextDecorationStyle::Double, strokeStyle);
}
} else {
// FIXME: Need to support text-decoration-skip: none.
m_context.drawLineForText(rect, m_isPrinting, style == TextDecorationStyle::Double, strokeStyle);
}
} else {
ASSERT(decoration == TextDecoration::LineThrough);
m_context.drawLineForText(rect, m_isPrinting, style == TextDecorationStyle::Double, strokeStyle);
}
};
bool areLinesOpaque = !m_isPrinting && (!m_decorations.contains(TextDecoration::Underline) || m_styles.underlineColor.isOpaque())
&& (!m_decorations.contains(TextDecoration::Overline) || m_styles.overlineColor.isOpaque())
&& (!m_decorations.contains(TextDecoration::LineThrough) || m_styles.linethroughColor.isOpaque());
int extraOffset = 0;
bool clipping = !areLinesOpaque && m_shadow && m_shadow->next();
if (clipping) {
FloatRect clipRect(localOrigin, FloatSize(m_width, fontMetrics.ascent() + 2));
for (const ShadowData* shadow = m_shadow; shadow; shadow = shadow->next()) {
int shadowExtent = shadow->paintingExtent();
FloatRect shadowRect(localOrigin, FloatSize(m_width, fontMetrics.ascent() + 2));
shadowRect.inflate(shadowExtent);
int shadowX = m_isHorizontal ? shadow->x() : shadow->y();
int shadowY = m_isHorizontal ? shadow->y() : -shadow->x();
shadowRect.move(shadowX, shadowY);
clipRect.unite(shadowRect);
extraOffset = std::max(extraOffset, std::max(0, shadowY) + shadowExtent);
}
m_context.save();
m_context.clip(clipRect);
extraOffset += fontMetrics.ascent() + 2;
localOrigin.move(0, extraOffset);
}
const ShadowData* shadow = m_shadow;
do {
if (shadow) {
if (!shadow->next()) {
// The last set of lines paints normally inside the clip.
localOrigin.move(0, -extraOffset);
extraOffset = 0;
}
int shadowX = m_isHorizontal ? shadow->x() : shadow->y();
int shadowY = m_isHorizontal ? shadow->y() : -shadow->x();
Color shadowColor = shadow->color();
if (m_shadowColorFilter)
m_shadowColorFilter->transformColor(shadowColor);
m_context.setShadow(FloatSize(shadowX, shadowY - extraOffset), shadow->radius(), shadowColor);
shadow = shadow->next();
}
// These decorations should match the visual overflows computed in visualOverflowForDecorations().
if (m_decorations.contains(TextDecoration::Underline)) {
float textDecorationBaseFontSize = 16;
auto defaultGap = m_lineStyle.computedFontSize() / textDecorationBaseFontSize;
float offset = computeUnderlineOffset(m_lineStyle.textUnderlinePosition(), m_lineStyle.textUnderlineOffset(), m_lineStyle.fontMetrics(), m_inlineTextBox, defaultGap);
float wavyOffset = m_styles.underlineStyle == TextDecorationStyle::Wavy ? m_wavyOffset : 0;
FloatRect rect(localOrigin, FloatSize(m_width, textDecorationThickness));
rect.move(0, offset + wavyOffset);
paintDecoration(TextDecoration::Underline, m_styles.underlineStyle, m_styles.underlineColor, rect);
}
if (m_decorations.contains(TextDecoration::Overline)) {
float wavyOffset = m_styles.overlineStyle == TextDecorationStyle::Wavy ? m_wavyOffset : 0;
FloatRect rect(localOrigin, FloatSize(m_width, textDecorationThickness));
float autoTextDecorationThickness = TextDecorationThickness::createWithAuto().resolve(m_lineStyle.computedFontSize(), fontMetrics);
rect.move(0, autoTextDecorationThickness - textDecorationThickness - wavyOffset);
paintDecoration(TextDecoration::Overline, m_styles.overlineStyle, m_styles.overlineColor, rect);
}
if (m_decorations.contains(TextDecoration::LineThrough)) {
FloatRect rect(localOrigin, FloatSize(m_width, textDecorationThickness));
float autoTextDecorationThickness = TextDecorationThickness::createWithAuto().resolve(m_lineStyle.computedFontSize(), fontMetrics);
auto center = 2 * fontMetrics.floatAscent() / 3 + autoTextDecorationThickness / 2;
rect.move(0, center - textDecorationThickness / 2);
paintDecoration(TextDecoration::LineThrough, m_styles.linethroughStyle, m_styles.linethroughColor, rect);
}
} while (shadow);
if (clipping)
m_context.restore();
else if (m_shadow)
m_context.clearShadow();
}
static void collectStylesForRenderer(TextDecorationPainter::Styles& result, const RenderObject& renderer, OptionSet<TextDecoration> remainingDecorations, bool firstLineStyle, PseudoId pseudoId)
{
auto extractDecorations = [&] (const RenderStyle& style, OptionSet<TextDecoration> decorations) {
auto color = TextDecorationPainter::decorationColor(style);
auto decorationStyle = style.textDecorationStyle();
if (decorations.contains(TextDecoration::Underline)) {
remainingDecorations.remove(TextDecoration::Underline);
result.underlineColor = color;
result.underlineStyle = decorationStyle;
}
if (decorations.contains(TextDecoration::Overline)) {
remainingDecorations.remove(TextDecoration::Overline);
result.overlineColor = color;
result.overlineStyle = decorationStyle;
}
if (decorations.contains(TextDecoration::LineThrough)) {
remainingDecorations.remove(TextDecoration::LineThrough);
result.linethroughColor = color;
result.linethroughStyle = decorationStyle;
}
};
auto styleForRenderer = [&] (const RenderObject& renderer) -> const RenderStyle& {
if (pseudoId != PseudoId::None && renderer.style().hasPseudoStyle(pseudoId)) {
if (is<RenderText>(renderer))
return *downcast<RenderText>(renderer).getCachedPseudoStyle(pseudoId);
return *downcast<RenderElement>(renderer).getCachedPseudoStyle(pseudoId);
}
return firstLineStyle ? renderer.firstLineStyle() : renderer.style();
};
auto* current = &renderer;
do {
const auto& style = styleForRenderer(*current);
extractDecorations(style, style.textDecoration());
if (current->isRubyText())
return;
current = current->parent();
if (current && current->isAnonymousBlock() && downcast<RenderBlock>(*current).continuation())
current = downcast<RenderBlock>(*current).continuation();
if (remainingDecorations.isEmpty())
break;
} while (current && !is<HTMLAnchorElement>(current->node()) && !is<HTMLFontElement>(current->node()));
// If we bailed out, use the element we bailed out at (typically a <font> or <a> element).
if (!remainingDecorations.isEmpty() && current)
extractDecorations(styleForRenderer(*current), remainingDecorations);
}
Color TextDecorationPainter::decorationColor(const RenderStyle& style)
{
// Check for text decoration color first.
auto result = style.visitedDependentColorWithColorFilter(CSSPropertyTextDecorationColor);
if (result.isValid())
return result;
if (style.hasPositiveStrokeWidth()) {
// Prefer stroke color if possible but not if it's fully transparent.
result = style.computedStrokeColor();
if (result.isVisible())
return result;
}
return style.visitedDependentColorWithColorFilter(CSSPropertyWebkitTextFillColor);
}
OptionSet<TextDecoration> TextDecorationPainter::textDecorationsInEffectForStyle(const TextDecorationPainter::Styles& style)
{
OptionSet<TextDecoration> decorations;
if (style.underlineColor.isValid())
decorations.add(TextDecoration::Underline);
if (style.overlineColor.isValid())
decorations.add(TextDecoration::Overline);
if (style.linethroughColor.isValid())
decorations.add(TextDecoration::LineThrough);
return decorations;
};
auto TextDecorationPainter::stylesForRenderer(const RenderObject& renderer, OptionSet<TextDecoration> requestedDecorations, bool firstLineStyle, PseudoId pseudoId) -> Styles
{
Styles result;
collectStylesForRenderer(result, renderer, requestedDecorations, false, pseudoId);
if (firstLineStyle)
collectStylesForRenderer(result, renderer, requestedDecorations, true, pseudoId);
return result;
}
} // namespace WebCore