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RenderBlockLineLayout.cpp
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/*
* Copyright (C) 2000 Lars Knoll (knoll@kde.org)
* Copyright (C) 2003, 2004, 2006, 2007, 2008, 2009, 2010, 2011 Apple Inc. All right reserved.
* Copyright (C) 2010 Google 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 "BidiResolver.h"
#include "Hyphenation.h"
#include "InlineIterator.h"
#include "InlineTextBox.h"
#include "Logging.h"
#include "RenderArena.h"
#include "RenderCombineText.h"
#include "RenderFlowThread.h"
#include "RenderInline.h"
#include "RenderLayer.h"
#include "RenderListMarker.h"
#include "RenderRubyRun.h"
#include "RenderView.h"
#include "Settings.h"
#include "TrailingFloatsRootInlineBox.h"
#include "VerticalPositionCache.h"
#include "break_lines.h"
#include <wtf/AlwaysInline.h>
#include <wtf/RefCountedLeakCounter.h>
#include <wtf/StdLibExtras.h>
#include <wtf/Vector.h>
#include <wtf/unicode/CharacterNames.h>
#if ENABLE(CSS_EXCLUSIONS)
#include "ExclusionShapeInsideInfo.h"
#endif
#if ENABLE(SVG)
#include "RenderSVGInlineText.h"
#include "SVGRootInlineBox.h"
#endif
using namespace std;
using namespace WTF;
using namespace Unicode;
namespace WebCore {
// We don't let our line box tree for a single line get any deeper than this.
const unsigned cMaxLineDepth = 200;
#if ENABLE(CSS_EXCLUSIONS)
static inline ExclusionShapeInsideInfo* layoutExclusionShapeInsideInfo(const RenderBlock* block)
{
return block->view()->layoutState()->exclusionShapeInsideInfo();
}
#endif
class LineWidth {
public:
LineWidth(RenderBlock* block, bool isFirstLine)
: m_block(block)
, m_uncommittedWidth(0)
, m_committedWidth(0)
, m_overhangWidth(0)
, m_left(0)
, m_right(0)
, m_availableWidth(0)
#if ENABLE(CSS_EXCLUSIONS)
, m_segment(0)
#endif
, m_isFirstLine(isFirstLine)
{
ASSERT(block);
#if ENABLE(CSS_EXCLUSIONS)
ExclusionShapeInsideInfo* exclusionShapeInsideInfo = layoutExclusionShapeInsideInfo(m_block);
// FIXME: Bug 91878: Add support for multiple segments, currently we only support one
if (exclusionShapeInsideInfo && exclusionShapeInsideInfo->hasSegments())
m_segment = &exclusionShapeInsideInfo->segments()[0];
#endif
updateAvailableWidth();
}
#if ENABLE(SUBPIXEL_LAYOUT)
bool fitsOnLine() const { return currentWidth() <= m_availableWidth; }
bool fitsOnLine(float extra) const { return currentWidth() + extra <= m_availableWidth; }
#else
bool fitsOnLine() const { return currentWidth() <= m_availableWidth; }
bool fitsOnLine(float extra) const { return currentWidth() + extra <= m_availableWidth; }
#endif
float currentWidth() const { return m_committedWidth + m_uncommittedWidth; }
// FIXME: We should eventually replace these three functions by ones that work on a higher abstraction.
float uncommittedWidth() const { return m_uncommittedWidth; }
float committedWidth() const { return m_committedWidth; }
float availableWidth() const { return m_availableWidth; }
void updateAvailableWidth();
void shrinkAvailableWidthForNewFloatIfNeeded(RenderBlock::FloatingObject*);
void addUncommittedWidth(float delta) { m_uncommittedWidth += delta; }
void commit()
{
m_committedWidth += m_uncommittedWidth;
m_uncommittedWidth = 0;
}
void applyOverhang(RenderRubyRun*, RenderObject* startRenderer, RenderObject* endRenderer);
void fitBelowFloats();
private:
void computeAvailableWidthFromLeftAndRight()
{
m_availableWidth = max(0.0f, m_right - m_left) + m_overhangWidth;
}
private:
RenderBlock* m_block;
float m_uncommittedWidth;
float m_committedWidth;
float m_overhangWidth; // The amount by which |m_availableWidth| has been inflated to account for possible contraction due to ruby overhang.
float m_left;
float m_right;
float m_availableWidth;
#if ENABLE(CSS_EXCLUSIONS)
const LineSegment* m_segment;
#endif
bool m_isFirstLine;
};
static LayoutUnit logicalHeightForLine(RenderBlock* block)
{
InlineFlowBox* lineBox = block->firstRootBox();
LayoutUnit logicalHeight = 0;
if (!lineBox)
return logicalHeight;
if (lineBox->firstChild() && lineBox->firstChild()->renderer() && lineBox->firstChild()->renderer()->isRenderBlock())
logicalHeight = toRenderBlock(lineBox->firstChild()->renderer())->logicalHeight();
else
logicalHeight = lineBox->height();
return logicalHeight;
}
inline void LineWidth::updateAvailableWidth()
{
LayoutUnit height = m_block->logicalHeight();
LayoutUnit logicalHeight = logicalHeightForLine(m_block);
m_left = m_block->logicalLeftOffsetForLine(height, m_isFirstLine, logicalHeight);
m_right = m_block->logicalRightOffsetForLine(height, m_isFirstLine, logicalHeight);
#if ENABLE(CSS_EXCLUSIONS)
if (m_segment) {
m_left = max<float>(m_segment->logicalLeft, m_left);
m_right = min<float>(m_segment->logicalRight, m_right);
}
#endif
computeAvailableWidthFromLeftAndRight();
}
inline void LineWidth::shrinkAvailableWidthForNewFloatIfNeeded(RenderBlock::FloatingObject* newFloat)
{
LayoutUnit height = m_block->logicalHeight();
if (height < m_block->logicalTopForFloat(newFloat) || height >= m_block->logicalBottomForFloat(newFloat))
return;
if (newFloat->type() == RenderBlock::FloatingObject::FloatLeft) {
m_left = m_block->pixelSnappedLogicalRightForFloat(newFloat);
if (m_isFirstLine && m_block->style()->isLeftToRightDirection())
m_left += floorToInt(m_block->textIndentOffset());
} else {
m_right = m_block->pixelSnappedLogicalLeftForFloat(newFloat);
if (m_isFirstLine && !m_block->style()->isLeftToRightDirection())
m_right -= floorToInt(m_block->textIndentOffset());
}
computeAvailableWidthFromLeftAndRight();
}
void LineWidth::applyOverhang(RenderRubyRun* rubyRun, RenderObject* startRenderer, RenderObject* endRenderer)
{
int startOverhang;
int endOverhang;
rubyRun->getOverhang(m_isFirstLine, startRenderer, endRenderer, startOverhang, endOverhang);
startOverhang = min<int>(startOverhang, m_committedWidth);
m_availableWidth += startOverhang;
endOverhang = max(min<int>(endOverhang, m_availableWidth - currentWidth()), 0);
m_availableWidth += endOverhang;
m_overhangWidth += startOverhang + endOverhang;
}
void LineWidth::fitBelowFloats()
{
ASSERT(!m_committedWidth);
ASSERT(!fitsOnLine());
LayoutUnit floatLogicalBottom;
LayoutUnit lastFloatLogicalBottom = m_block->logicalHeight();
float newLineWidth = m_availableWidth;
float newLineLeft = m_left;
float newLineRight = m_right;
while (true) {
floatLogicalBottom = m_block->nextFloatLogicalBottomBelow(lastFloatLogicalBottom);
if (floatLogicalBottom <= lastFloatLogicalBottom)
break;
newLineLeft = m_block->logicalLeftOffsetForLine(floatLogicalBottom, m_isFirstLine);
newLineRight = m_block->logicalRightOffsetForLine(floatLogicalBottom, m_isFirstLine);
newLineWidth = max(0.0f, newLineRight - newLineLeft);
lastFloatLogicalBottom = floatLogicalBottom;
if (newLineWidth >= m_uncommittedWidth)
break;
}
if (newLineWidth > m_availableWidth) {
m_block->setLogicalHeight(lastFloatLogicalBottom);
m_availableWidth = newLineWidth + m_overhangWidth;
m_left = newLineLeft;
m_right = newLineRight;
}
}
class LineInfo {
public:
LineInfo()
: m_isFirstLine(true)
, m_isLastLine(false)
, m_isEmpty(true)
, m_previousLineBrokeCleanly(true)
, m_floatPaginationStrut(0)
, m_runsFromLeadingWhitespace(0)
{ }
bool isFirstLine() const { return m_isFirstLine; }
bool isLastLine() const { return m_isLastLine; }
bool isEmpty() const { return m_isEmpty; }
bool previousLineBrokeCleanly() const { return m_previousLineBrokeCleanly; }
LayoutUnit floatPaginationStrut() const { return m_floatPaginationStrut; }
unsigned runsFromLeadingWhitespace() const { return m_runsFromLeadingWhitespace; }
void resetRunsFromLeadingWhitespace() { m_runsFromLeadingWhitespace = 0; }
void incrementRunsFromLeadingWhitespace() { m_runsFromLeadingWhitespace++; }
void setFirstLine(bool firstLine) { m_isFirstLine = firstLine; }
void setLastLine(bool lastLine) { m_isLastLine = lastLine; }
void setEmpty(bool empty, RenderBlock* block = 0, LineWidth* lineWidth = 0)
{
if (m_isEmpty == empty)
return;
m_isEmpty = empty;
if (!empty && block && floatPaginationStrut()) {
block->setLogicalHeight(block->logicalHeight() + floatPaginationStrut());
setFloatPaginationStrut(0);
lineWidth->updateAvailableWidth();
}
}
void setPreviousLineBrokeCleanly(bool previousLineBrokeCleanly) { m_previousLineBrokeCleanly = previousLineBrokeCleanly; }
void setFloatPaginationStrut(LayoutUnit strut) { m_floatPaginationStrut = strut; }
private:
bool m_isFirstLine;
bool m_isLastLine;
bool m_isEmpty;
bool m_previousLineBrokeCleanly;
LayoutUnit m_floatPaginationStrut;
unsigned m_runsFromLeadingWhitespace;
};
static inline LayoutUnit borderPaddingMarginStart(RenderInline* child)
{
return child->marginStart() + child->paddingStart() + child->borderStart();
}
static inline LayoutUnit borderPaddingMarginEnd(RenderInline* child)
{
return child->marginEnd() + child->paddingEnd() + child->borderEnd();
}
static bool shouldAddBorderPaddingMargin(RenderObject* child, bool &checkSide)
{
if (!child || (child->isText() && !toRenderText(child)->textLength()))
return true;
checkSide = false;
return checkSide;
}
static LayoutUnit inlineLogicalWidth(RenderObject* child, bool start = true, bool end = true)
{
unsigned lineDepth = 1;
LayoutUnit extraWidth = 0;
RenderObject* parent = child->parent();
while (parent->isRenderInline() && lineDepth++ < cMaxLineDepth) {
RenderInline* parentAsRenderInline = toRenderInline(parent);
if (start && shouldAddBorderPaddingMargin(child->previousSibling(), start))
extraWidth += borderPaddingMarginStart(parentAsRenderInline);
if (end && shouldAddBorderPaddingMargin(child->nextSibling(), end))
extraWidth += borderPaddingMarginEnd(parentAsRenderInline);
if (!start && !end)
return extraWidth;
child = parent;
parent = child->parent();
}
return extraWidth;
}
static void determineDirectionality(TextDirection& dir, InlineIterator iter)
{
while (!iter.atEnd()) {
if (iter.atParagraphSeparator())
return;
if (UChar current = iter.current()) {
Direction charDirection = direction(current);
if (charDirection == LeftToRight) {
dir = LTR;
return;
}
if (charDirection == RightToLeft || charDirection == RightToLeftArabic) {
dir = RTL;
return;
}
}
iter.increment();
}
}
static void checkMidpoints(LineMidpointState& lineMidpointState, InlineIterator& lBreak)
{
// Check to see if our last midpoint is a start point beyond the line break. If so,
// shave it off the list, and shave off a trailing space if the previous end point doesn't
// preserve whitespace.
if (lBreak.m_obj && lineMidpointState.numMidpoints && !(lineMidpointState.numMidpoints % 2)) {
InlineIterator* midpoints = lineMidpointState.midpoints.data();
InlineIterator& endpoint = midpoints[lineMidpointState.numMidpoints - 2];
const InlineIterator& startpoint = midpoints[lineMidpointState.numMidpoints - 1];
InlineIterator currpoint = endpoint;
while (!currpoint.atEnd() && currpoint != startpoint && currpoint != lBreak)
currpoint.increment();
if (currpoint == lBreak) {
// We hit the line break before the start point. Shave off the start point.
lineMidpointState.numMidpoints--;
if (endpoint.m_obj->style()->collapseWhiteSpace())
endpoint.m_pos--;
}
}
}
static void addMidpoint(LineMidpointState& lineMidpointState, const InlineIterator& midpoint)
{
if (lineMidpointState.midpoints.size() <= lineMidpointState.numMidpoints)
lineMidpointState.midpoints.grow(lineMidpointState.numMidpoints + 10);
InlineIterator* midpoints = lineMidpointState.midpoints.data();
midpoints[lineMidpointState.numMidpoints++] = midpoint;
}
static inline BidiRun* createRun(int start, int end, RenderObject* obj, InlineBidiResolver& resolver)
{
return new (obj->renderArena()) BidiRun(start, end, obj, resolver.context(), resolver.dir());
}
void RenderBlock::appendRunsForObject(BidiRunList<BidiRun>& runs, int start, int end, RenderObject* obj, InlineBidiResolver& resolver)
{
if (start > end || shouldSkipCreatingRunsForObject(obj))
return;
LineMidpointState& lineMidpointState = resolver.midpointState();
bool haveNextMidpoint = (lineMidpointState.currentMidpoint < lineMidpointState.numMidpoints);
InlineIterator nextMidpoint;
if (haveNextMidpoint)
nextMidpoint = lineMidpointState.midpoints[lineMidpointState.currentMidpoint];
if (lineMidpointState.betweenMidpoints) {
if (!(haveNextMidpoint && nextMidpoint.m_obj == obj))
return;
// This is a new start point. Stop ignoring objects and
// adjust our start.
lineMidpointState.betweenMidpoints = false;
start = nextMidpoint.m_pos;
lineMidpointState.currentMidpoint++;
if (start < end)
return appendRunsForObject(runs, start, end, obj, resolver);
} else {
if (!haveNextMidpoint || (obj != nextMidpoint.m_obj)) {
runs.addRun(createRun(start, end, obj, resolver));
return;
}
// An end midpoint has been encountered within our object. We
// need to go ahead and append a run with our endpoint.
if (static_cast<int>(nextMidpoint.m_pos + 1) <= end) {
lineMidpointState.betweenMidpoints = true;
lineMidpointState.currentMidpoint++;
if (nextMidpoint.m_pos != UINT_MAX) { // UINT_MAX means stop at the object and don't include any of it.
if (static_cast<int>(nextMidpoint.m_pos + 1) > start)
runs.addRun(createRun(start, nextMidpoint.m_pos + 1, obj, resolver));
return appendRunsForObject(runs, nextMidpoint.m_pos + 1, end, obj, resolver);
}
} else
runs.addRun(createRun(start, end, obj, resolver));
}
}
static inline InlineBox* createInlineBoxForRenderer(RenderObject* obj, bool isRootLineBox, bool isOnlyRun = false)
{
if (isRootLineBox)
return toRenderBlock(obj)->createAndAppendRootInlineBox();
if (obj->isText()) {
InlineTextBox* textBox = toRenderText(obj)->createInlineTextBox();
// We only treat a box as text for a <br> if we are on a line by ourself or in strict mode
// (Note the use of strict mode. In "almost strict" mode, we don't treat the box for <br> as text.)
if (obj->isBR())
textBox->setIsText(isOnlyRun || obj->document()->inNoQuirksMode());
return textBox;
}
if (obj->isBox())
return toRenderBox(obj)->createInlineBox();
return toRenderInline(obj)->createAndAppendInlineFlowBox();
}
static inline void dirtyLineBoxesForRenderer(RenderObject* o, bool fullLayout)
{
if (o->isText()) {
RenderText* renderText = toRenderText(o);
renderText->updateTextIfNeeded(); // FIXME: Counters depend on this hack. No clue why. Should be investigated and removed.
renderText->dirtyLineBoxes(fullLayout);
} else
toRenderInline(o)->dirtyLineBoxes(fullLayout);
}
static bool parentIsConstructedOrHaveNext(InlineFlowBox* parentBox)
{
do {
if (parentBox->isConstructed() || parentBox->nextOnLine())
return true;
parentBox = parentBox->parent();
} while (parentBox);
return false;
}
InlineFlowBox* RenderBlock::createLineBoxes(RenderObject* obj, const LineInfo& lineInfo, InlineBox* childBox)
{
// See if we have an unconstructed line box for this object that is also
// the last item on the line.
unsigned lineDepth = 1;
InlineFlowBox* parentBox = 0;
InlineFlowBox* result = 0;
bool hasDefaultLineBoxContain = style()->lineBoxContain() == RenderStyle::initialLineBoxContain();
do {
ASSERT(obj->isRenderInline() || obj == this);
RenderInline* inlineFlow = (obj != this) ? toRenderInline(obj) : 0;
// Get the last box we made for this render object.
parentBox = inlineFlow ? inlineFlow->lastLineBox() : toRenderBlock(obj)->lastLineBox();
// If this box or its ancestor is constructed then it is from a previous line, and we need
// to make a new box for our line. If this box or its ancestor is unconstructed but it has
// something following it on the line, then we know we have to make a new box
// as well. In this situation our inline has actually been split in two on
// the same line (this can happen with very fancy language mixtures).
bool constructedNewBox = false;
bool allowedToConstructNewBox = !hasDefaultLineBoxContain || !inlineFlow || inlineFlow->alwaysCreateLineBoxes();
bool canUseExistingParentBox = parentBox && !parentIsConstructedOrHaveNext(parentBox);
if (allowedToConstructNewBox && !canUseExistingParentBox) {
// We need to make a new box for this render object. Once
// made, we need to place it at the end of the current line.
InlineBox* newBox = createInlineBoxForRenderer(obj, obj == this);
ASSERT(newBox->isInlineFlowBox());
parentBox = toInlineFlowBox(newBox);
parentBox->setFirstLineStyleBit(lineInfo.isFirstLine());
parentBox->setIsHorizontal(isHorizontalWritingMode());
if (!hasDefaultLineBoxContain)
parentBox->clearDescendantsHaveSameLineHeightAndBaseline();
constructedNewBox = true;
}
if (constructedNewBox || canUseExistingParentBox) {
if (!result)
result = parentBox;
// If we have hit the block itself, then |box| represents the root
// inline box for the line, and it doesn't have to be appended to any parent
// inline.
if (childBox)
parentBox->addToLine(childBox);
if (!constructedNewBox || obj == this)
break;
childBox = parentBox;
}
// If we've exceeded our line depth, then jump straight to the root and skip all the remaining
// intermediate inline flows.
obj = (++lineDepth >= cMaxLineDepth) ? this : obj->parent();
} while (true);
return result;
}
template <typename CharacterType>
static inline bool endsWithASCIISpaces(const CharacterType* characters, unsigned pos, unsigned end)
{
while (isASCIISpace(characters[pos])) {
pos++;
if (pos >= end)
return true;
}
return false;
}
static bool reachedEndOfTextRenderer(const BidiRunList<BidiRun>& bidiRuns)
{
BidiRun* run = bidiRuns.logicallyLastRun();
if (!run)
return true;
unsigned pos = run->stop();
RenderObject* r = run->m_object;
if (!r->isText() || r->isBR())
return false;
RenderText* renderText = toRenderText(r);
unsigned length = renderText->textLength();
if (pos >= length)
return true;
if (renderText->is8Bit())
return endsWithASCIISpaces(renderText->characters8(), pos, length);
return endsWithASCIISpaces(renderText->characters16(), pos, length);
}
RootInlineBox* RenderBlock::constructLine(BidiRunList<BidiRun>& bidiRuns, const LineInfo& lineInfo)
{
ASSERT(bidiRuns.firstRun());
bool rootHasSelectedChildren = false;
InlineFlowBox* parentBox = 0;
int runCount = bidiRuns.runCount() - lineInfo.runsFromLeadingWhitespace();
for (BidiRun* r = bidiRuns.firstRun(); r; r = r->next()) {
// Create a box for our object.
bool isOnlyRun = (runCount == 1);
if (runCount == 2 && !r->m_object->isListMarker())
isOnlyRun = (!style()->isLeftToRightDirection() ? bidiRuns.lastRun() : bidiRuns.firstRun())->m_object->isListMarker();
if (lineInfo.isEmpty())
continue;
InlineBox* box = createInlineBoxForRenderer(r->m_object, false, isOnlyRun);
r->m_box = box;
ASSERT(box);
if (!box)
continue;
if (!rootHasSelectedChildren && box->renderer()->selectionState() != RenderObject::SelectionNone)
rootHasSelectedChildren = true;
// If we have no parent box yet, or if the run is not simply a sibling,
// then we need to construct inline boxes as necessary to properly enclose the
// run's inline box.
if (!parentBox || parentBox->renderer() != r->m_object->parent())
// Create new inline boxes all the way back to the appropriate insertion point.
parentBox = createLineBoxes(r->m_object->parent(), lineInfo, box);
else {
// Append the inline box to this line.
parentBox->addToLine(box);
}
bool visuallyOrdered = r->m_object->style()->rtlOrdering() == VisualOrder;
box->setBidiLevel(r->level());
if (box->isInlineTextBox()) {
InlineTextBox* text = toInlineTextBox(box);
text->setStart(r->m_start);
text->setLen(r->m_stop - r->m_start);
text->setDirOverride(r->dirOverride(visuallyOrdered));
if (r->m_hasHyphen)
text->setHasHyphen(true);
}
}
// We should have a root inline box. It should be unconstructed and
// be the last continuation of our line list.
ASSERT(lastLineBox() && !lastLineBox()->isConstructed());
// Set the m_selectedChildren flag on the root inline box if one of the leaf inline box
// from the bidi runs walk above has a selection state.
if (rootHasSelectedChildren)
lastLineBox()->root()->setHasSelectedChildren(true);
// Set bits on our inline flow boxes that indicate which sides should
// paint borders/margins/padding. This knowledge will ultimately be used when
// we determine the horizontal positions and widths of all the inline boxes on
// the line.
bool isLogicallyLastRunWrapped = bidiRuns.logicallyLastRun()->m_object && bidiRuns.logicallyLastRun()->m_object->isText() ? !reachedEndOfTextRenderer(bidiRuns) : true;
lastLineBox()->determineSpacingForFlowBoxes(lineInfo.isLastLine(), isLogicallyLastRunWrapped, bidiRuns.logicallyLastRun()->m_object);
// Now mark the line boxes as being constructed.
lastLineBox()->setConstructed();
// Return the last line.
return lastRootBox();
}
ETextAlign RenderBlock::textAlignmentForLine(bool endsWithSoftBreak) const
{
ETextAlign alignment = style()->textAlign();
if (!endsWithSoftBreak && alignment == JUSTIFY)
alignment = TASTART;
return alignment;
}
static void updateLogicalWidthForLeftAlignedBlock(bool isLeftToRightDirection, BidiRun* trailingSpaceRun, float& logicalLeft, float& totalLogicalWidth, float availableLogicalWidth)
{
// The direction of the block should determine what happens with wide lines.
// In particular with RTL blocks, wide lines should still spill out to the left.
if (isLeftToRightDirection) {
if (totalLogicalWidth > availableLogicalWidth && trailingSpaceRun)
trailingSpaceRun->m_box->setLogicalWidth(max<float>(0, trailingSpaceRun->m_box->logicalWidth() - totalLogicalWidth + availableLogicalWidth));
return;
}
if (trailingSpaceRun)
trailingSpaceRun->m_box->setLogicalWidth(0);
else if (totalLogicalWidth > availableLogicalWidth)
logicalLeft -= (totalLogicalWidth - availableLogicalWidth);
}
static void updateLogicalWidthForRightAlignedBlock(bool isLeftToRightDirection, BidiRun* trailingSpaceRun, float& logicalLeft, float& totalLogicalWidth, float availableLogicalWidth)
{
// Wide lines spill out of the block based off direction.
// So even if text-align is right, if direction is LTR, wide lines should overflow out of the right
// side of the block.
if (isLeftToRightDirection) {
if (trailingSpaceRun) {
totalLogicalWidth -= trailingSpaceRun->m_box->logicalWidth();
trailingSpaceRun->m_box->setLogicalWidth(0);
}
if (totalLogicalWidth < availableLogicalWidth)
logicalLeft += availableLogicalWidth - totalLogicalWidth;
return;
}
if (totalLogicalWidth > availableLogicalWidth && trailingSpaceRun) {
trailingSpaceRun->m_box->setLogicalWidth(max<float>(0, trailingSpaceRun->m_box->logicalWidth() - totalLogicalWidth + availableLogicalWidth));
totalLogicalWidth -= trailingSpaceRun->m_box->logicalWidth();
} else
logicalLeft += availableLogicalWidth - totalLogicalWidth;
}
static void updateLogicalWidthForCenterAlignedBlock(bool isLeftToRightDirection, BidiRun* trailingSpaceRun, float& logicalLeft, float& totalLogicalWidth, float availableLogicalWidth)
{
float trailingSpaceWidth = 0;
if (trailingSpaceRun) {
totalLogicalWidth -= trailingSpaceRun->m_box->logicalWidth();
trailingSpaceWidth = min(trailingSpaceRun->m_box->logicalWidth(), (availableLogicalWidth - totalLogicalWidth + 1) / 2);
trailingSpaceRun->m_box->setLogicalWidth(max<float>(0, trailingSpaceWidth));
}
if (isLeftToRightDirection)
logicalLeft += max<float>((availableLogicalWidth - totalLogicalWidth) / 2, 0);
else
logicalLeft += totalLogicalWidth > availableLogicalWidth ? (availableLogicalWidth - totalLogicalWidth) : (availableLogicalWidth - totalLogicalWidth) / 2 - trailingSpaceWidth;
}
void RenderBlock::setMarginsForRubyRun(BidiRun* run, RenderRubyRun* renderer, RenderObject* previousObject, const LineInfo& lineInfo)
{
int startOverhang;
int endOverhang;
RenderObject* nextObject = 0;
for (BidiRun* runWithNextObject = run->next(); runWithNextObject; runWithNextObject = runWithNextObject->next()) {
if (!runWithNextObject->m_object->isOutOfFlowPositioned() && !runWithNextObject->m_box->isLineBreak()) {
nextObject = runWithNextObject->m_object;
break;
}
}
renderer->getOverhang(lineInfo.isFirstLine(), renderer->style()->isLeftToRightDirection() ? previousObject : nextObject, renderer->style()->isLeftToRightDirection() ? nextObject : previousObject, startOverhang, endOverhang);
setMarginStartForChild(renderer, -startOverhang);
setMarginEndForChild(renderer, -endOverhang);
}
static inline float measureHyphenWidth(RenderText* renderer, const Font& font)
{
RenderStyle* style = renderer->style();
return font.width(RenderBlock::constructTextRun(renderer, font, style->hyphenString().string(), style));
}
class WordMeasurement {
public:
WordMeasurement()
: renderer(0)
, width(0)
, startOffset(0)
, endOffset(0)
{
}
RenderText* renderer;
float width;
int startOffset;
int endOffset;
HashSet<const SimpleFontData*> fallbackFonts;
};
static inline void setLogicalWidthForTextRun(RootInlineBox* lineBox, BidiRun* run, RenderText* renderer, float xPos, const LineInfo& lineInfo,
GlyphOverflowAndFallbackFontsMap& textBoxDataMap, VerticalPositionCache& verticalPositionCache, WordMeasurements& wordMeasurements)
{
#if !(PLATFORM(CHROMIUM) && OS(DARWIN))
UNUSED_PARAM(wordMeasurements);
#endif
HashSet<const SimpleFontData*> fallbackFonts;
GlyphOverflow glyphOverflow;
const Font& font = renderer->style(lineInfo.isFirstLine())->font();
// Always compute glyph overflow if the block's line-box-contain value is "glyphs".
if (lineBox->fitsToGlyphs()) {
// If we don't stick out of the root line's font box, then don't bother computing our glyph overflow. This optimization
// will keep us from computing glyph bounds in nearly all cases.
bool includeRootLine = lineBox->includesRootLineBoxFontOrLeading();
int baselineShift = lineBox->verticalPositionForBox(run->m_box, verticalPositionCache);
int rootDescent = includeRootLine ? font.fontMetrics().descent() : 0;
int rootAscent = includeRootLine ? font.fontMetrics().ascent() : 0;
int boxAscent = font.fontMetrics().ascent() - baselineShift;
int boxDescent = font.fontMetrics().descent() + baselineShift;
if (boxAscent > rootDescent || boxDescent > rootAscent)
glyphOverflow.computeBounds = true;
}
LayoutUnit hyphenWidth = 0;
if (toInlineTextBox(run->m_box)->hasHyphen()) {
const Font& font = renderer->style(lineInfo.isFirstLine())->font();
hyphenWidth = measureHyphenWidth(renderer, font);
}
float measuredWidth = 0;
#if !(PLATFORM(CHROMIUM) && OS(DARWIN))
bool kerningIsEnabled = font.typesettingFeatures() & Kerning;
// Since we don't cache glyph overflows, we need to re-measure the run if
// the style is linebox-contain: glyph.
if (!lineBox->fitsToGlyphs() && renderer->canUseSimpleFontCodePath()) {
int lastEndOffset = run->m_start;
for (size_t i = 0, size = wordMeasurements.size(); i < size && lastEndOffset < run->m_stop; ++i) {
const WordMeasurement& wordMeasurement = wordMeasurements[i];
if (wordMeasurement.width <=0 || wordMeasurement.startOffset == wordMeasurement.endOffset)
continue;
if (wordMeasurement.renderer != renderer || wordMeasurement.startOffset != lastEndOffset || wordMeasurement.endOffset > run->m_stop)
continue;
lastEndOffset = wordMeasurement.endOffset;
if (kerningIsEnabled && lastEndOffset == run->m_stop) {
measuredWidth += renderer->width(wordMeasurement.startOffset, lastEndOffset - wordMeasurement.startOffset, xPos, lineInfo.isFirstLine());
if (i > 0)
measuredWidth += renderer->style()->wordSpacing();
} else
measuredWidth += wordMeasurement.width;
if (!wordMeasurement.fallbackFonts.isEmpty()) {
HashSet<const SimpleFontData*>::const_iterator end = wordMeasurement.fallbackFonts.end();
for (HashSet<const SimpleFontData*>::const_iterator it = wordMeasurement.fallbackFonts.begin(); it != end; ++it)
fallbackFonts.add(*it);
}
}
if (measuredWidth && lastEndOffset != run->m_stop) {
// If we don't have enough cached data, we'll measure the run again.
measuredWidth = 0;
fallbackFonts.clear();
}
}
#endif
if (!measuredWidth)
measuredWidth = renderer->width(run->m_start, run->m_stop - run->m_start, xPos, lineInfo.isFirstLine(), &fallbackFonts, &glyphOverflow);
run->m_box->setLogicalWidth(measuredWidth + hyphenWidth);
if (!fallbackFonts.isEmpty()) {
ASSERT(run->m_box->isText());
GlyphOverflowAndFallbackFontsMap::iterator it = textBoxDataMap.add(toInlineTextBox(run->m_box), make_pair(Vector<const SimpleFontData*>(), GlyphOverflow())).iterator;
ASSERT(it->value.first.isEmpty());
copyToVector(fallbackFonts, it->value.first);
run->m_box->parent()->clearDescendantsHaveSameLineHeightAndBaseline();
}
if ((glyphOverflow.top || glyphOverflow.bottom || glyphOverflow.left || glyphOverflow.right)) {
ASSERT(run->m_box->isText());
GlyphOverflowAndFallbackFontsMap::iterator it = textBoxDataMap.add(toInlineTextBox(run->m_box), make_pair(Vector<const SimpleFontData*>(), GlyphOverflow())).iterator;
it->value.second = glyphOverflow;
run->m_box->clearKnownToHaveNoOverflow();
}
}
static inline void computeExpansionForJustifiedText(BidiRun* firstRun, BidiRun* trailingSpaceRun, Vector<unsigned, 16>& expansionOpportunities, unsigned expansionOpportunityCount, float& totalLogicalWidth, float availableLogicalWidth)
{
if (!expansionOpportunityCount || availableLogicalWidth <= totalLogicalWidth)
return;
size_t i = 0;
for (BidiRun* r = firstRun; r; r = r->next()) {
if (!r->m_box || r == trailingSpaceRun)
continue;
if (r->m_object->isText()) {
unsigned opportunitiesInRun = expansionOpportunities[i++];
ASSERT(opportunitiesInRun <= expansionOpportunityCount);
// Only justify text if whitespace is collapsed.
if (r->m_object->style()->collapseWhiteSpace()) {
InlineTextBox* textBox = toInlineTextBox(r->m_box);
int expansion = (availableLogicalWidth - totalLogicalWidth) * opportunitiesInRun / expansionOpportunityCount;
textBox->setExpansion(expansion);
totalLogicalWidth += expansion;
}
expansionOpportunityCount -= opportunitiesInRun;
if (!expansionOpportunityCount)
break;
}
}
}
void RenderBlock::updateLogicalWidthForAlignment(const ETextAlign& textAlign, BidiRun* trailingSpaceRun, float& logicalLeft, float& totalLogicalWidth, float& availableLogicalWidth, int expansionOpportunityCount)
{
// Armed with the total width of the line (without justification),
// we now examine our text-align property in order to determine where to position the
// objects horizontally. The total width of the line can be increased if we end up
// justifying text.
switch (textAlign) {
case LEFT:
case WEBKIT_LEFT:
updateLogicalWidthForLeftAlignedBlock(style()->isLeftToRightDirection(), trailingSpaceRun, logicalLeft, totalLogicalWidth, availableLogicalWidth);
break;
case RIGHT:
case WEBKIT_RIGHT:
updateLogicalWidthForRightAlignedBlock(style()->isLeftToRightDirection(), trailingSpaceRun, logicalLeft, totalLogicalWidth, availableLogicalWidth);
break;
case CENTER:
case WEBKIT_CENTER:
updateLogicalWidthForCenterAlignedBlock(style()->isLeftToRightDirection(), trailingSpaceRun, logicalLeft, totalLogicalWidth, availableLogicalWidth);
break;
case JUSTIFY:
adjustInlineDirectionLineBounds(expansionOpportunityCount, logicalLeft, availableLogicalWidth);
if (expansionOpportunityCount) {
if (trailingSpaceRun) {
totalLogicalWidth -= trailingSpaceRun->m_box->logicalWidth();
trailingSpaceRun->m_box->setLogicalWidth(0);
}
break;
}
// Fall through
case TASTART:
if (style()->isLeftToRightDirection())
updateLogicalWidthForLeftAlignedBlock(style()->isLeftToRightDirection(), trailingSpaceRun, logicalLeft, totalLogicalWidth, availableLogicalWidth);
else
updateLogicalWidthForRightAlignedBlock(style()->isLeftToRightDirection(), trailingSpaceRun, logicalLeft, totalLogicalWidth, availableLogicalWidth);
break;
case TAEND:
if (style()->isLeftToRightDirection())
updateLogicalWidthForRightAlignedBlock(style()->isLeftToRightDirection(), trailingSpaceRun, logicalLeft, totalLogicalWidth, availableLogicalWidth);
else
updateLogicalWidthForLeftAlignedBlock(style()->isLeftToRightDirection(), trailingSpaceRun, logicalLeft, totalLogicalWidth, availableLogicalWidth);
break;
}
}
void RenderBlock::computeInlineDirectionPositionsForLine(RootInlineBox* lineBox, const LineInfo& lineInfo, BidiRun* firstRun, BidiRun* trailingSpaceRun, bool reachedEnd,
GlyphOverflowAndFallbackFontsMap& textBoxDataMap, VerticalPositionCache& verticalPositionCache, WordMeasurements& wordMeasurements)
{
ETextAlign textAlign = textAlignmentForLine(!reachedEnd && !lineBox->endsWithBreak());
LayoutUnit lineLogicalHeight = logicalHeightForLine(this);
// CSS 2.1: "'Text-indent' only affects a line if it is the first formatted line of an element. For example, the first line of an anonymous block
// box is only affected if it is the first child of its parent element."
bool firstLine = lineInfo.isFirstLine() && !(isAnonymousBlock() && parent()->firstChild() != this);
float logicalLeft = pixelSnappedLogicalLeftOffsetForLine(logicalHeight(), firstLine, lineLogicalHeight);
float logicalRight = pixelSnappedLogicalRightOffsetForLine(logicalHeight(), firstLine, lineLogicalHeight);
#if ENABLE(CSS_EXCLUSIONS)
ExclusionShapeInsideInfo* exclusionShapeInsideInfo = layoutExclusionShapeInsideInfo(this);
if (exclusionShapeInsideInfo && exclusionShapeInsideInfo->hasSegments()) {
logicalLeft = max<float>(roundToInt(exclusionShapeInsideInfo->segments()[0].logicalLeft), logicalLeft);
logicalRight = min<float>(floorToInt(exclusionShapeInsideInfo->segments()[0].logicalRight), logicalRight);
}
#endif
float availableLogicalWidth = logicalRight - logicalLeft;
bool needsWordSpacing = false;
float totalLogicalWidth = lineBox->getFlowSpacingLogicalWidth();
unsigned expansionOpportunityCount = 0;
bool isAfterExpansion = true;
Vector<unsigned, 16> expansionOpportunities;
RenderObject* previousObject = 0;
for (BidiRun* r = firstRun; r; r = r->next()) {
if (!r->m_box || r->m_object->isOutOfFlowPositioned() || r->m_box->isLineBreak())
continue; // Positioned objects are only participating to figure out their
// correct static x position. They have no effect on the width.
// Similarly, line break boxes have no effect on the width.
if (r->m_object->isText()) {
RenderText* rt = toRenderText(r->m_object);
if (textAlign == JUSTIFY && r != trailingSpaceRun) {
if (!isAfterExpansion)
toInlineTextBox(r->m_box)->setCanHaveLeadingExpansion(true);
unsigned opportunitiesInRun;
if (rt->is8Bit())
opportunitiesInRun = Font::expansionOpportunityCount(rt->characters8() + r->m_start, r->m_stop - r->m_start, r->m_box->direction(), isAfterExpansion);
else
opportunitiesInRun = Font::expansionOpportunityCount(rt->characters16() + r->m_start, r->m_stop - r->m_start, r->m_box->direction(), isAfterExpansion);
expansionOpportunities.append(opportunitiesInRun);
expansionOpportunityCount += opportunitiesInRun;
}
if (int length = rt->textLength()) {
if (!r->m_start && needsWordSpacing && isSpaceOrNewline(rt->characterAt(r->m_start)))
totalLogicalWidth += rt->style(lineInfo.isFirstLine())->font().wordSpacing();
needsWordSpacing = !isSpaceOrNewline(rt->characterAt(r->m_stop - 1)) && r->m_stop == length;
}
setLogicalWidthForTextRun(lineBox, r, rt, totalLogicalWidth, lineInfo, textBoxDataMap, verticalPositionCache, wordMeasurements);
} else {
isAfterExpansion = false;
if (!r->m_object->isRenderInline()) {
RenderBox* renderBox = toRenderBox(r->m_object);
if (renderBox->isRubyRun())
setMarginsForRubyRun(r, toRenderRubyRun(renderBox), previousObject, lineInfo);
r->m_box->setLogicalWidth(logicalWidthForChild(renderBox));
totalLogicalWidth += marginStartForChild(renderBox) + marginEndForChild(renderBox);
}
}
totalLogicalWidth += r->m_box->logicalWidth();
previousObject = r->m_object;
}
if (isAfterExpansion && !expansionOpportunities.isEmpty()) {
expansionOpportunities.last()--;
expansionOpportunityCount--;
}
updateLogicalWidthForAlignment(textAlign, trailingSpaceRun, logicalLeft, totalLogicalWidth, availableLogicalWidth, expansionOpportunityCount);
computeExpansionForJustifiedText(firstRun, trailingSpaceRun, expansionOpportunities, expansionOpportunityCount, totalLogicalWidth, availableLogicalWidth);
// The widths of all runs are now known. We can now place every inline box (and
// compute accurate widths for the inline flow boxes).
needsWordSpacing = false;
lineBox->placeBoxesInInlineDirection(logicalLeft, needsWordSpacing, textBoxDataMap);
}
void RenderBlock::computeBlockDirectionPositionsForLine(RootInlineBox* lineBox, BidiRun* firstRun, GlyphOverflowAndFallbackFontsMap& textBoxDataMap,
VerticalPositionCache& verticalPositionCache)
{
setLogicalHeight(lineBox->alignBoxesInBlockDirection(logicalHeight(), textBoxDataMap, verticalPositionCache));
// Now make sure we place replaced render objects correctly.
for (BidiRun* r = firstRun; r; r = r->next()) {
ASSERT(r->m_box);
if (!r->m_box)
continue; // Skip runs with no line boxes.
// Align positioned boxes with the top of the line box. This is
// a reasonable approximation of an appropriate y position.
if (r->m_object->isOutOfFlowPositioned())
r->m_box->setLogicalTop(logicalHeight());
// Position is used to properly position both replaced elements and
// to update the static normal flow x/y of positioned elements.
if (r->m_object->isText())
toRenderText(r->m_object)->positionLineBox(r->m_box);
else if (r->m_object->isBox())
toRenderBox(r->m_object)->positionLineBox(r->m_box);
}
// Positioned objects and zero-length text nodes destroy their boxes in
// position(), which unnecessarily dirties the line.
lineBox->markDirty(false);
}
static inline bool isCollapsibleSpace(UChar character, RenderText* renderer)
{
if (character == ' ' || character == '\t' || character == softHyphen)
return true;
if (character == '\n')
return !renderer->style()->preserveNewline();
if (character == noBreakSpace)
return renderer->style()->nbspMode() == SPACE;
return false;
}