blob: 4159b157b9de5e47553a8d4c0ebd272866895ace [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 "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 FloatPoint& start, const FloatPoint& end, float strokeThickness, float fontSize)
{
FloatPoint p1 = start;
FloatPoint p2 = end;
context.adjustLineToPixelBoundaries(p1, p2, strokeThickness, context.strokeStyle());
Path path;
path.moveTo(p1);
float controlPointDistance;
float step;
getWavyStrokeParameters(fontSize, controlPointDistance, step);
bool isVerticalLine = (p1.x() == p2.x());
if (isVerticalLine) {
ASSERT(p1.x() == p2.x());
float xAxis = p1.x();
float y1;
float y2;
if (p1.y() < p2.y()) {
y1 = p1.y();
y2 = p2.y();
} else {
y1 = p2.y();
y2 = p1.y();
}
adjustStepToDecorationLength(step, controlPointDistance, y2 - y1);
FloatPoint controlPoint1(xAxis + controlPointDistance, 0);
FloatPoint controlPoint2(xAxis - controlPointDistance, 0);
for (float y = y1; y + 2 * step <= y2;) {
controlPoint1.setY(y + step);
controlPoint2.setY(y + step);
y += 2 * step;
path.addBezierCurveTo(controlPoint1, controlPoint2, FloatPoint(xAxis, y));
}
} else {
ASSERT(p1.y() == p2.y());
float yAxis = p1.y();
float x1;
float x2;
if (p1.x() < p2.x()) {
x1 = p1.x();
x2 = p2.x();
} else {
x1 = p2.x();
x2 = p1.x();
}
adjustStepToDecorationLength(step, controlPointDistance, x2 - x1);
FloatPoint controlPoint1(0, yAxis + controlPointDistance);
FloatPoint controlPoint2(0, yAxis - controlPointDistance);
for (float x = x1; x + 2 * step <= x2;) {
controlPoint1.setX(x + step);
controlPoint2.setX(x + step);
x += 2 * step;
path.addBezierCurveTo(controlPoint1, controlPoint2, FloatPoint(x, yAxis));
}
}
context.setShouldAntialias(true);
context.strokePath(path);
}
#if ENABLE(CSS3_TEXT_DECORATION_SKIP_INK)
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 void drawSkipInkUnderline(GraphicsContext& context, const FontCascade& font, const TextRun& textRun, const FloatPoint& textOrigin, const FloatPoint& localOrigin,
float underlineOffset, float width, bool isPrinting, bool doubleLines, StrokeStyle strokeStyle)
{
FloatPoint adjustedLocalOrigin = localOrigin;
adjustedLocalOrigin.move(0, underlineOffset);
FloatRect underlineBoundingBox = context.computeUnderlineBoundsForText(adjustedLocalOrigin, width, isPrinting);
DashArray intersections = font.dashesForIntersectionsWithRect(textRun, textOrigin, underlineBoundingBox);
DashArray a = translateIntersectionPointsToSkipInkBoundaries(intersections, underlineBoundingBox.height(), width);
ASSERT(!(a.size() % 2));
context.drawLinesForText(adjustedLocalOrigin, a, isPrinting, doubleLines, strokeStyle);
}
#endif
static StrokeStyle textDecorationStyleToStrokeStyle(TextDecorationStyle decorationStyle)
{
StrokeStyle strokeStyle = SolidStroke;
switch (decorationStyle) {
case TextDecorationStyleSolid:
strokeStyle = SolidStroke;
break;
case TextDecorationStyleDouble:
strokeStyle = DoubleStroke;
break;
case TextDecorationStyleDotted:
strokeStyle = DottedStroke;
break;
case TextDecorationStyleDashed:
strokeStyle = DashedStroke;
break;
case TextDecorationStyleWavy:
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, unsigned decorations, const RenderText& renderer, bool isFirstLine, std::optional<Styles> styles)
: m_context { context }
, m_decorations { OptionSet<TextDecoration>::fromRaw(decorations) }
, m_wavyOffset { wavyOffsetFromDecoration() }
, m_isPrinting { renderer.document().printing() }
, m_styles { styles ? *WTFMove(styles) : stylesForRenderer(renderer, decorations, isFirstLine, NOPSEUDO) }
, m_lineStyle { isFirstLine ? renderer.firstLineStyle() : renderer.style() }
{
}
void TextDecorationPainter::paintTextDecoration(const TextRun& textRun, const FloatPoint& textOrigin, const FloatPoint& boxOrigin)
{
#if !ENABLE(CSS3_TEXT_DECORATION_SKIP_INK)
UNUSED_PARAM(textRun);
UNUSED_PARAM(textOrigin);
#endif
ASSERT(m_font);
float textDecorationThickness = textDecorationStrokeThickness(m_lineStyle.computedFontPixelSize());
m_context.setStrokeThickness(textDecorationThickness);
FloatPoint localOrigin = boxOrigin;
auto paintDecoration = [&] (TextDecoration decoration, TextDecorationStyle style, const Color& color, const FloatPoint& start, const FloatPoint& end, int offset) {
m_context.setStrokeColor(color);
auto strokeStyle = textDecorationStyleToStrokeStyle(style);
if (style == TextDecorationStyleWavy)
strokeWavyTextDecoration(m_context, start, end, textDecorationThickness, m_lineStyle.computedFontPixelSize());
else if (decoration == TextDecorationUnderline || decoration == TextDecorationOverline) {
#if ENABLE(CSS3_TEXT_DECORATION_SKIP_INK)
if ((m_lineStyle.textDecorationSkip() == TextDecorationSkipInk || m_lineStyle.textDecorationSkip() == TextDecorationSkipAuto) && m_isHorizontal) {
if (!m_context.paintingDisabled())
drawSkipInkUnderline(m_context, *m_font, textRun, textOrigin, localOrigin, offset, m_width, m_isPrinting, style == TextDecorationStyleDouble, strokeStyle);
} else
// FIXME: Need to support text-decoration-skip: none.
#endif
m_context.drawLineForText(start, m_width, m_isPrinting, style == TextDecorationStyleDouble, strokeStyle);
} else {
ASSERT(decoration == TextDecorationLineThrough);
m_context.drawLineForText(start, m_width, m_isPrinting, style == TextDecorationStyleDouble, strokeStyle);
}
};
bool areLinesOpaque = !m_isPrinting && (!m_decorations.contains(TextDecorationUnderline) || m_styles.underlineColor.isOpaque())
&& (!m_decorations.contains(TextDecorationOverline) || m_styles.overlineColor.isOpaque())
&& (!m_decorations.contains(TextDecorationLineThrough) || m_styles.linethroughColor.isOpaque());
int extraOffset = 0;
bool clipping = !areLinesOpaque && m_shadow && m_shadow->next();
if (clipping) {
FloatRect clipRect(localOrigin, FloatSize(m_width, m_baseline + 2));
for (const ShadowData* shadow = m_shadow; shadow; shadow = shadow->next()) {
int shadowExtent = shadow->paintingExtent();
FloatRect shadowRect(localOrigin, FloatSize(m_width, m_baseline + 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 += m_baseline + 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();
m_context.setShadow(FloatSize(shadowX, shadowY - extraOffset), shadow->radius(), shadow->color());
shadow = shadow->next();
}
// These decorations should match the visual overflows computed in visualOverflowForDecorations().
if (m_decorations.contains(TextDecorationUnderline)) {
int offset = computeUnderlineOffset(m_lineStyle.textUnderlinePosition(), m_lineStyle.fontMetrics(), m_inlineTextBox, textDecorationThickness);
float wavyOffset = m_styles.underlineStyle == TextDecorationStyleWavy ? m_wavyOffset : 0;
FloatPoint start = localOrigin + FloatSize(0, offset + wavyOffset);
FloatPoint end = localOrigin + FloatSize(m_width, offset + wavyOffset);
paintDecoration(TextDecorationUnderline, m_styles.underlineStyle, m_styles.underlineColor, start, end, offset);
}
if (m_decorations.contains(TextDecorationOverline)) {
float wavyOffset = m_styles.overlineStyle == TextDecorationStyleWavy ? m_wavyOffset : 0;
FloatPoint start = localOrigin - FloatSize(0, wavyOffset);
FloatPoint end = localOrigin + FloatSize(m_width, -wavyOffset);
paintDecoration(TextDecorationOverline, m_styles.overlineStyle, m_styles.overlineColor, start, end, 0);
}
if (m_decorations.contains(TextDecorationLineThrough)) {
FloatPoint start = localOrigin + FloatSize(0, 2 * m_baseline / 3);
FloatPoint end = localOrigin + FloatSize(m_width, 2 * m_baseline / 3);
paintDecoration(TextDecorationLineThrough, m_styles.linethroughStyle, m_styles.linethroughColor, start, end, 0);
}
} while (shadow);
if (clipping)
m_context.restore();
else if (m_shadow)
m_context.clearShadow();
}
static Color decorationColor(const RenderStyle& style)
{
// Check for text decoration color first.
Color result = style.visitedDependentColor(CSSPropertyWebkitTextDecorationColor);
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.visitedDependentColor(CSSPropertyWebkitTextFillColor);
}
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 = decorationColor(style);
auto decorationStyle = style.textDecorationStyle();
if (decorations.contains(TextDecorationUnderline)) {
remainingDecorations -= TextDecorationUnderline;
result.underlineColor = color;
result.underlineStyle = decorationStyle;
}
if (decorations.contains(TextDecorationOverline)) {
remainingDecorations -= TextDecorationOverline;
result.overlineColor = color;
result.overlineStyle = decorationStyle;
}
if (decorations.contains(TextDecorationLineThrough)) {
remainingDecorations -= TextDecorationLineThrough;
result.linethroughColor = color;
result.linethroughStyle = decorationStyle;
}
};
auto styleForRenderer = [&] (const RenderObject& renderer) -> const RenderStyle& {
if (pseudoId != NOPSEUDO && 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, OptionSet<TextDecoration>::fromRaw(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);
}
auto TextDecorationPainter::stylesForRenderer(const RenderObject& renderer, unsigned requestedDecorations, bool firstLineStyle, PseudoId pseudoId) -> Styles
{
Styles result;
collectStylesForRenderer(result, renderer, OptionSet<TextDecoration>::fromRaw(requestedDecorations), false, pseudoId);
if (firstLineStyle)
collectStylesForRenderer(result, renderer, OptionSet<TextDecoration>::fromRaw(requestedDecorations), true, pseudoId);
return result;
}
} // namespace WebCore