| /* |
| * Copyright (C) 2013 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. AND ITS CONTRIBUTORS ``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 ITS 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 "SimpleLineLayout.h" |
| |
| #include "DocumentMarkerController.h" |
| #include "FontCache.h" |
| #include "Frame.h" |
| #include "GraphicsContext.h" |
| #include "HTMLTextFormControlElement.h" |
| #include "HitTestLocation.h" |
| #include "HitTestRequest.h" |
| #include "HitTestResult.h" |
| #include "Hyphenation.h" |
| #include "InlineTextBox.h" |
| #include "LineWidth.h" |
| #include "Logging.h" |
| #include "PaintInfo.h" |
| #include "RenderBlockFlow.h" |
| #include "RenderChildIterator.h" |
| #include "RenderFragmentedFlow.h" |
| #include "RenderLineBreak.h" |
| #include "RenderMultiColumnFlow.h" |
| #include "RenderStyle.h" |
| #include "RenderText.h" |
| #include "RenderTextControl.h" |
| #include "RenderView.h" |
| #include "Settings.h" |
| #include "SimpleLineLayoutFlowContents.h" |
| #include "SimpleLineLayoutFunctions.h" |
| #include "SimpleLineLayoutResolver.h" |
| #include "SimpleLineLayoutTextFragmentIterator.h" |
| #include "Text.h" |
| #include "TextPaintStyle.h" |
| #include <pal/Logging.h> |
| |
| namespace WebCore { |
| namespace SimpleLineLayout { |
| |
| #ifndef NDEBUG |
| #define SET_REASON_AND_RETURN_IF_NEEDED(reason, reasons, includeReasons) { \ |
| reasons |= reason; \ |
| if (includeReasons == IncludeReasons::First) \ |
| return reasons; \ |
| } |
| #else |
| #define SET_REASON_AND_RETURN_IF_NEEDED(reason, reasons, includeReasons) { \ |
| ASSERT_UNUSED(includeReasons, includeReasons == IncludeReasons::First); \ |
| reasons |= reason; \ |
| return reasons; \ |
| } |
| #endif |
| |
| |
| template <typename CharacterType> AvoidanceReasonFlags canUseForCharacter(CharacterType, bool textIsJustified, IncludeReasons); |
| |
| template<> AvoidanceReasonFlags canUseForCharacter(UChar character, bool textIsJustified, IncludeReasons includeReasons) |
| { |
| AvoidanceReasonFlags reasons = { }; |
| if (textIsJustified) { |
| // Include characters up to Latin Extended-B and some punctuation range when text is justified. |
| bool isLatinIncludingExtendedB = character <= 0x01FF; |
| bool isPunctuationRange = character >= 0x2010 && character <= 0x2027; |
| if (!(isLatinIncludingExtendedB || isPunctuationRange)) |
| SET_REASON_AND_RETURN_IF_NEEDED(FlowHasJustifiedNonLatinText, reasons, includeReasons); |
| } |
| |
| if (U16_IS_SURROGATE(character)) |
| SET_REASON_AND_RETURN_IF_NEEDED(FlowTextHasSurrogatePair, reasons, includeReasons); |
| |
| UCharDirection direction = u_charDirection(character); |
| if (direction == U_RIGHT_TO_LEFT || direction == U_RIGHT_TO_LEFT_ARABIC |
| || direction == U_RIGHT_TO_LEFT_EMBEDDING || direction == U_RIGHT_TO_LEFT_OVERRIDE |
| || direction == U_LEFT_TO_RIGHT_EMBEDDING || direction == U_LEFT_TO_RIGHT_OVERRIDE |
| || direction == U_POP_DIRECTIONAL_FORMAT || direction == U_BOUNDARY_NEUTRAL) |
| SET_REASON_AND_RETURN_IF_NEEDED(FlowTextHasDirectionCharacter, reasons, includeReasons); |
| |
| return reasons; |
| } |
| |
| template<> AvoidanceReasonFlags canUseForCharacter(LChar, bool, IncludeReasons) |
| { |
| return { }; |
| } |
| |
| template <typename CharacterType> |
| static AvoidanceReasonFlags canUseForText(const CharacterType* text, unsigned length, const FontCascade& fontCascade, Optional<float> lineHeightConstraint, |
| bool textIsJustified, IncludeReasons includeReasons) |
| { |
| AvoidanceReasonFlags reasons = { }; |
| auto& primaryFont = fontCascade.primaryFont(); |
| auto& fontMetrics = primaryFont.fontMetrics(); |
| auto availableSpaceForGlyphAscent = fontMetrics.ascent(); |
| auto availableSpaceForGlyphDescent = fontMetrics.descent(); |
| if (lineHeightConstraint) { |
| auto lineHeightPadding = *lineHeightConstraint - fontMetrics.height(); |
| availableSpaceForGlyphAscent += lineHeightPadding / 2; |
| availableSpaceForGlyphDescent += lineHeightPadding / 2; |
| } |
| |
| for (unsigned i = 0; i < length; ++i) { |
| auto character = text[i]; |
| if (FontCascade::treatAsSpace(character)) |
| continue; |
| |
| if (character == softHyphen) |
| SET_REASON_AND_RETURN_IF_NEEDED(FlowTextHasSoftHyphen, reasons, includeReasons); |
| |
| auto characterReasons = canUseForCharacter(character, textIsJustified, includeReasons); |
| if (characterReasons != NoReason) |
| SET_REASON_AND_RETURN_IF_NEEDED(characterReasons, reasons, includeReasons); |
| |
| auto glyphData = fontCascade.glyphDataForCharacter(character, false); |
| if (!glyphData.isValid() || glyphData.font != &primaryFont) |
| SET_REASON_AND_RETURN_IF_NEEDED(FlowPrimaryFontIsInsufficient, reasons, includeReasons); |
| |
| if (lineHeightConstraint) { |
| auto bounds = primaryFont.boundsForGlyph(glyphData.glyph); |
| if (ceilf(-bounds.y()) > availableSpaceForGlyphAscent || ceilf(bounds.maxY()) > availableSpaceForGlyphDescent) |
| SET_REASON_AND_RETURN_IF_NEEDED(FlowFontHasOverflowGlyph, reasons, includeReasons); |
| } |
| } |
| return reasons; |
| } |
| |
| static AvoidanceReasonFlags canUseForText(StringView text, const FontCascade& fontCascade, Optional<float> lineHeightConstraint, bool textIsJustified, IncludeReasons includeReasons) |
| { |
| if (text.is8Bit()) |
| return canUseForText(text.characters8(), text.length(), fontCascade, lineHeightConstraint, textIsJustified, includeReasons); |
| return canUseForText(text.characters16(), text.length(), fontCascade, lineHeightConstraint, textIsJustified, includeReasons); |
| } |
| |
| static AvoidanceReasonFlags canUseForFontAndText(const RenderBlockFlow& flow, IncludeReasons includeReasons) |
| { |
| AvoidanceReasonFlags reasons = { }; |
| // We assume that all lines have metrics based purely on the primary font. |
| const auto& style = flow.style(); |
| auto& fontCascade = style.fontCascade(); |
| if (fontCascade.primaryFont().isInterstitial()) |
| SET_REASON_AND_RETURN_IF_NEEDED(FlowIsMissingPrimaryFont, reasons, includeReasons); |
| Optional<float> lineHeightConstraint; |
| if (style.lineBoxContain() & LineBoxContainGlyphs) |
| lineHeightConstraint = lineHeightFromFlow(flow).toFloat(); |
| bool flowIsJustified = style.textAlign() == TextAlignMode::Justify; |
| for (const auto& textRenderer : childrenOfType<RenderText>(flow)) { |
| // FIXME: Do not return until after checking all children. |
| if (textRenderer.text().isEmpty()) |
| SET_REASON_AND_RETURN_IF_NEEDED(FlowTextIsEmpty, reasons, includeReasons); |
| if (textRenderer.isCombineText()) |
| SET_REASON_AND_RETURN_IF_NEEDED(FlowTextIsCombineText, reasons, includeReasons); |
| if (textRenderer.isCounter()) |
| SET_REASON_AND_RETURN_IF_NEEDED(FlowTextIsRenderCounter, reasons, includeReasons); |
| if (textRenderer.isQuote()) |
| SET_REASON_AND_RETURN_IF_NEEDED(FlowTextIsRenderQuote, reasons, includeReasons); |
| if (textRenderer.isTextFragment()) |
| SET_REASON_AND_RETURN_IF_NEEDED(FlowTextIsTextFragment, reasons, includeReasons); |
| if (textRenderer.isSVGInlineText()) |
| SET_REASON_AND_RETURN_IF_NEEDED(FlowTextIsSVGInlineText, reasons, includeReasons); |
| if (!textRenderer.canUseSimpleFontCodePath()) { |
| // No need to check the code path at this point. We already know it can't be simple. |
| SET_REASON_AND_RETURN_IF_NEEDED(FlowHasComplexFontCodePath, reasons, includeReasons); |
| } else { |
| TextRun run(String(textRenderer.text())); |
| run.setCharacterScanForCodePath(false); |
| if (style.fontCascade().codePath(run) != FontCascade::Simple) |
| SET_REASON_AND_RETURN_IF_NEEDED(FlowHasComplexFontCodePath, reasons, includeReasons); |
| } |
| |
| auto textReasons = canUseForText(textRenderer.stringView(), fontCascade, lineHeightConstraint, flowIsJustified, includeReasons); |
| if (textReasons != NoReason) |
| SET_REASON_AND_RETURN_IF_NEEDED(textReasons, reasons, includeReasons); |
| } |
| return reasons; |
| } |
| |
| static AvoidanceReasonFlags canUseForStyle(const RenderStyle& style, IncludeReasons includeReasons) |
| { |
| AvoidanceReasonFlags reasons = { }; |
| if (style.textOverflow() == TextOverflow::Ellipsis) |
| SET_REASON_AND_RETURN_IF_NEEDED(FlowHasTextOverflow, reasons, includeReasons); |
| if (style.textUnderlinePosition() != TextUnderlinePosition::Auto || !style.textUnderlineOffset().isAuto() || !style.textDecorationThickness().isAuto()) |
| SET_REASON_AND_RETURN_IF_NEEDED(FlowHasUnsupportedUnderlineDecoration, reasons, includeReasons); |
| // Non-visible overflow should be pretty easy to support. |
| if (style.overflowX() != Overflow::Visible || style.overflowY() != Overflow::Visible) |
| SET_REASON_AND_RETURN_IF_NEEDED(FlowHasOverflowNotVisible, reasons, includeReasons); |
| if (!style.isLeftToRightDirection()) |
| SET_REASON_AND_RETURN_IF_NEEDED(FlowIsNotLTR, reasons, includeReasons); |
| if (!(style.lineBoxContain() & LineBoxContainBlock)) |
| SET_REASON_AND_RETURN_IF_NEEDED(FlowHasLineBoxContainProperty, reasons, includeReasons); |
| if (style.writingMode() != TopToBottomWritingMode) |
| SET_REASON_AND_RETURN_IF_NEEDED(FlowIsNotTopToBottom, reasons, includeReasons); |
| if (style.lineBreak() != LineBreak::Auto) |
| SET_REASON_AND_RETURN_IF_NEEDED(FlowHasLineBreak, reasons, includeReasons); |
| if (style.unicodeBidi() != UBNormal) |
| SET_REASON_AND_RETURN_IF_NEEDED(FlowHasNonNormalUnicodeBiDi, reasons, includeReasons); |
| if (style.rtlOrdering() != Order::Logical) |
| SET_REASON_AND_RETURN_IF_NEEDED(FlowHasRTLOrdering, reasons, includeReasons); |
| if (style.lineAlign() != LineAlign::None) |
| SET_REASON_AND_RETURN_IF_NEEDED(FlowHasLineAlignEdges, reasons, includeReasons); |
| if (style.lineSnap() != LineSnap::None) |
| SET_REASON_AND_RETURN_IF_NEEDED(FlowHasLineSnap, reasons, includeReasons); |
| if (style.textEmphasisFill() != TextEmphasisFill::Filled || style.textEmphasisMark() != TextEmphasisMark::None) |
| SET_REASON_AND_RETURN_IF_NEEDED(FlowHasTextEmphasisFillOrMark, reasons, includeReasons); |
| if (style.textShadow()) |
| SET_REASON_AND_RETURN_IF_NEEDED(FlowHasTextShadow, reasons, includeReasons); |
| if (style.hasPseudoStyle(PseudoId::FirstLine)) |
| SET_REASON_AND_RETURN_IF_NEEDED(FlowHasPseudoFirstLine, reasons, includeReasons); |
| if (style.hasPseudoStyle(PseudoId::FirstLetter)) |
| SET_REASON_AND_RETURN_IF_NEEDED(FlowHasPseudoFirstLetter, reasons, includeReasons); |
| if (style.hasTextCombine()) |
| SET_REASON_AND_RETURN_IF_NEEDED(FlowHasTextCombine, reasons, includeReasons); |
| if (style.backgroundClip() == FillBox::Text) |
| SET_REASON_AND_RETURN_IF_NEEDED(FlowHasTextFillBox, reasons, includeReasons); |
| if (style.borderFit() == BorderFit::Lines) |
| SET_REASON_AND_RETURN_IF_NEEDED(FlowHasBorderFitLines, reasons, includeReasons); |
| if (style.lineBreak() != LineBreak::Auto) |
| SET_REASON_AND_RETURN_IF_NEEDED(FlowHasNonAutoLineBreak, reasons, includeReasons); |
| if (style.nbspMode() != NBSPMode::Normal) |
| SET_REASON_AND_RETURN_IF_NEEDED(FlowHasWebKitNBSPMode, reasons, includeReasons); |
| if (style.hyphens() == Hyphens::Auto) { |
| auto textReasons = canUseForText(style.hyphenString(), style.fontCascade(), WTF::nullopt, false, includeReasons); |
| if (textReasons != NoReason) |
| SET_REASON_AND_RETURN_IF_NEEDED(textReasons, reasons, includeReasons); |
| } |
| return reasons; |
| } |
| |
| AvoidanceReasonFlags canUseForWithReason(const RenderBlockFlow& flow, IncludeReasons includeReasons) |
| { |
| #ifndef NDEBUG |
| static std::once_flag onceFlag; |
| std::call_once(onceFlag, [] { |
| PAL::registerNotifyCallback("com.apple.WebKit.showSimpleLineLayoutCoverage", WTF::Function<void()> { printSimpleLineLayoutCoverage }); |
| PAL::registerNotifyCallback("com.apple.WebKit.showSimpleLineLayoutReasons", WTF::Function<void()> { printSimpleLineLayoutBlockList }); |
| PAL::registerNotifyCallback("com.apple.WebKit.toggleSimpleLineLayout", WTF::Function<void()> { toggleSimpleLineLayout }); |
| }); |
| #endif |
| AvoidanceReasonFlags reasons = { }; |
| if (!flow.settings().simpleLineLayoutEnabled()) |
| SET_REASON_AND_RETURN_IF_NEEDED(FeatureIsDisabled, reasons, includeReasons); |
| if (!flow.parent()) |
| SET_REASON_AND_RETURN_IF_NEEDED(FlowHasNoParent, reasons, includeReasons); |
| if (!flow.firstChild()) |
| SET_REASON_AND_RETURN_IF_NEEDED(FlowHasNoChild, reasons, includeReasons); |
| if (flow.fragmentedFlowState() != RenderObject::NotInsideFragmentedFlow) { |
| auto* fragmentedFlow = flow.enclosingFragmentedFlow(); |
| if (!is<RenderMultiColumnFlow>(fragmentedFlow)) |
| SET_REASON_AND_RETURN_IF_NEEDED(FlowIsInsideANonMultiColumnThread, reasons, includeReasons); |
| auto& columnThread = downcast<RenderMultiColumnFlow>(*fragmentedFlow); |
| if (columnThread.parent() != &flow.view()) |
| SET_REASON_AND_RETURN_IF_NEEDED(MultiColumnFlowIsNotTopLevel, reasons, includeReasons); |
| if (columnThread.hasColumnSpanner()) |
| SET_REASON_AND_RETURN_IF_NEEDED(MultiColumnFlowHasColumnSpanner, reasons, includeReasons); |
| auto& style = flow.style(); |
| if (style.verticalAlign() != VerticalAlign::Baseline) |
| SET_REASON_AND_RETURN_IF_NEEDED(MultiColumnFlowVerticalAlign, reasons, includeReasons); |
| if (style.isFloating()) |
| SET_REASON_AND_RETURN_IF_NEEDED(MultiColumnFlowIsFloating, reasons, includeReasons); |
| } |
| if (!flow.isHorizontalWritingMode()) |
| SET_REASON_AND_RETURN_IF_NEEDED(FlowHasHorizonalWritingMode, reasons, includeReasons); |
| if (flow.hasOutline()) |
| SET_REASON_AND_RETURN_IF_NEEDED(FlowHasOutline, reasons, includeReasons); |
| if (flow.isRubyText() || flow.isRubyBase()) |
| SET_REASON_AND_RETURN_IF_NEEDED(FlowIsRuby, reasons, includeReasons); |
| if (!flow.style().hangingPunctuation().isEmpty()) |
| SET_REASON_AND_RETURN_IF_NEEDED(FlowHasHangingPunctuation, reasons, includeReasons); |
| |
| // Printing does pagination without a flow thread. |
| if (flow.document().paginated()) |
| SET_REASON_AND_RETURN_IF_NEEDED(FlowIsPaginated, reasons, includeReasons); |
| if (flow.firstLineBlock()) |
| SET_REASON_AND_RETURN_IF_NEEDED(FlowHasPseudoFirstLine, reasons, includeReasons); |
| if (flow.isAnonymousBlock() && flow.parent()->style().textOverflow() == TextOverflow::Ellipsis) |
| SET_REASON_AND_RETURN_IF_NEEDED(FlowHasTextOverflow, reasons, includeReasons); |
| if (flow.parent()->isDeprecatedFlexibleBox()) |
| SET_REASON_AND_RETURN_IF_NEEDED(FlowIsDepricatedFlexBox, reasons, includeReasons); |
| // FIXME: Placeholders do something strange. |
| if (is<RenderTextControl>(*flow.parent()) && downcast<RenderTextControl>(*flow.parent()).textFormControlElement().placeholderElement()) |
| SET_REASON_AND_RETURN_IF_NEEDED(FlowParentIsPlaceholderElement, reasons, includeReasons); |
| // FIXME: Implementation of wrap=hard looks into lineboxes. |
| if (flow.parent()->isTextArea() && flow.parent()->element()->hasAttributeWithoutSynchronization(HTMLNames::wrapAttr)) |
| SET_REASON_AND_RETURN_IF_NEEDED(FlowParentIsTextAreaWithWrapping, reasons, includeReasons); |
| // This currently covers <blockflow>#text</blockflow>, <blockflow>#text<br></blockflow> and mutiple (sibling) RenderText cases. |
| // The <blockflow><inline>#text</inline></blockflow> case is also popular and should be relatively easy to cover. |
| for (const auto* child = flow.firstChild(); child;) { |
| if (child->selectionState() != RenderObject::SelectionNone) |
| SET_REASON_AND_RETURN_IF_NEEDED(FlowChildIsSelected, reasons, includeReasons); |
| if (is<RenderText>(*child)) { |
| const auto& renderText = downcast<RenderText>(*child); |
| if (renderText.textNode() && !renderText.document().markers().markersFor(*renderText.textNode()).isEmpty()) |
| SET_REASON_AND_RETURN_IF_NEEDED(FlowIncludesDocumentMarkers, reasons, includeReasons); |
| child = child->nextSibling(); |
| continue; |
| } |
| if (is<RenderLineBreak>(child) && !downcast<RenderLineBreak>(*child).isWBR() && child->style().clear() == Clear::None) { |
| child = child->nextSibling(); |
| continue; |
| } |
| SET_REASON_AND_RETURN_IF_NEEDED(FlowHasNonSupportedChild, reasons, includeReasons); |
| break; |
| } |
| auto styleReasons = canUseForStyle(flow.style(), includeReasons); |
| if (styleReasons != NoReason) |
| SET_REASON_AND_RETURN_IF_NEEDED(styleReasons, reasons, includeReasons); |
| // We can't use the code path if any lines would need to be shifted below floats. This is because we don't keep per-line y coordinates. |
| if (flow.containsFloats()) { |
| float minimumWidthNeeded = std::numeric_limits<float>::max(); |
| for (const auto& textRenderer : childrenOfType<RenderText>(flow)) { |
| minimumWidthNeeded = std::min(minimumWidthNeeded, textRenderer.minLogicalWidth()); |
| |
| for (auto& floatingObject : *flow.floatingObjectSet()) { |
| ASSERT(floatingObject); |
| // if a float has a shape, we cannot tell if content will need to be shifted until after we lay it out, |
| // since the amount of space is not uniform for the height of the float. |
| if (floatingObject->renderer().shapeOutsideInfo()) |
| SET_REASON_AND_RETURN_IF_NEEDED(FlowHasUnsupportedFloat, reasons, includeReasons); |
| float availableWidth = flow.availableLogicalWidthForLine(floatingObject->y(), DoNotIndentText); |
| if (availableWidth < minimumWidthNeeded) |
| SET_REASON_AND_RETURN_IF_NEEDED(FlowHasUnsupportedFloat, reasons, includeReasons); |
| } |
| } |
| } |
| auto fontAndTextReasons = canUseForFontAndText(flow, includeReasons); |
| if (fontAndTextReasons != NoReason) |
| SET_REASON_AND_RETURN_IF_NEEDED(fontAndTextReasons, reasons, includeReasons); |
| return reasons; |
| } |
| |
| bool canUseFor(const RenderBlockFlow& flow) |
| { |
| return canUseForWithReason(flow, IncludeReasons::First) == NoReason; |
| } |
| |
| static float computeLineLeft(TextAlignMode textAlign, float availableWidth, float committedWidth, float logicalLeftOffset) |
| { |
| float remainingWidth = availableWidth - committedWidth; |
| float left = logicalLeftOffset; |
| switch (textAlign) { |
| case TextAlignMode::Left: |
| case TextAlignMode::WebKitLeft: |
| case TextAlignMode::Start: |
| return left; |
| case TextAlignMode::Right: |
| case TextAlignMode::WebKitRight: |
| case TextAlignMode::End: |
| return left + std::max<float>(remainingWidth, 0); |
| case TextAlignMode::Center: |
| case TextAlignMode::WebKitCenter: |
| return left + std::max<float>(remainingWidth / 2, 0); |
| case TextAlignMode::Justify: |
| ASSERT_NOT_REACHED(); |
| break; |
| } |
| ASSERT_NOT_REACHED(); |
| return 0; |
| } |
| |
| static void revertAllRunsOnCurrentLine(Layout::RunVector& runs) |
| { |
| while (!runs.isEmpty() && !runs.last().isEndOfLine) |
| runs.removeLast(); |
| } |
| |
| static void revertRuns(Layout::RunVector& runs, unsigned positionToRevertTo, float width) |
| { |
| while (runs.size()) { |
| auto& lastRun = runs.last(); |
| if (lastRun.end <= positionToRevertTo) |
| break; |
| if (lastRun.start >= positionToRevertTo) { |
| // Revert this run completely. |
| width -= (lastRun.logicalRight - lastRun.logicalLeft); |
| runs.removeLast(); |
| } else { |
| lastRun.logicalRight -= width; |
| width = 0; |
| lastRun.end = positionToRevertTo; |
| // Partial removal. |
| break; |
| } |
| } |
| } |
| |
| class LineState { |
| public: |
| void setAvailableWidth(float width) { m_availableWidth = width; } |
| void setCollapedWhitespaceWidth(float width) { m_collapsedWhitespaceWidth = width; } |
| void setLogicalLeftOffset(float offset) { m_logicalLeftOffset = offset; } |
| void setOverflowedFragment(const TextFragmentIterator::TextFragment& fragment) { m_overflowedFragment = fragment; } |
| void setNeedsAllFragments() |
| { |
| ASSERT(!m_fragments); |
| m_fragments.emplace(); |
| } |
| void setHyphenationDisabled() { m_hyphenationDisabled = true; } |
| bool isHyphenationDisabled() const { return m_hyphenationDisabled; } |
| |
| float availableWidth() const { return m_availableWidth; } |
| float logicalLeftOffset() const { return m_logicalLeftOffset; } |
| const TextFragmentIterator::TextFragment& overflowedFragment() const { return m_overflowedFragment; } |
| bool hasTrailingWhitespace() const { return m_lastFragment.type() == TextFragmentIterator::TextFragment::Whitespace && m_lastFragment.length() > 0; } |
| bool hasWhitespaceFragments() const { return m_lastWhitespaceFragment != WTF::nullopt; } |
| TextFragmentIterator::TextFragment lastFragment() const { return m_lastFragment; } |
| bool isWhitespaceOnly() const { return m_trailingWhitespaceWidth && m_runsWidth == m_trailingWhitespaceWidth; } |
| bool fits(float extra) const { return m_availableWidth >= m_runsWidth + extra; } |
| bool firstCharacterFits() const { return m_firstCharacterFits; } |
| float width() const { return m_runsWidth; } |
| std::pair<unsigned, bool> expansionOpportunityCount(unsigned from, unsigned to) const |
| { |
| ASSERT(m_fragments); |
| // linebreak runs are special. |
| if (from == to) |
| return std::make_pair(0, false); |
| unsigned expansionOpportunityCount = 0; |
| auto previousFragmentType = TextFragmentIterator::TextFragment::ContentEnd; |
| for (const auto& fragment : *m_fragments) { |
| if (fragment.end() <= from) |
| continue; |
| auto currentFragmentType = fragment.type(); |
| auto expansionOpportunity = this->expansionOpportunity(currentFragmentType, previousFragmentType); |
| if (expansionOpportunity) |
| ++expansionOpportunityCount; |
| previousFragmentType = currentFragmentType; |
| if (fragment.end() >= to) |
| return std::make_pair(expansionOpportunityCount, expansionOpportunity); |
| } |
| ASSERT_NOT_REACHED(); |
| return std::make_pair(expansionOpportunityCount, false); |
| } |
| |
| bool isEmpty() const |
| { |
| if (!m_lastFragment.isValid()) |
| return true; |
| if (!m_lastCompleteFragment.isEmpty()) |
| return false; |
| return m_lastFragment.overlapsToNextRenderer(); |
| } |
| |
| static inline unsigned endPositionForCollapsedFragment(const TextFragmentIterator::TextFragment& fragment) |
| { |
| return fragment.isCollapsed() ? fragment.start() + 1 : fragment.end(); |
| } |
| |
| void appendFragmentAndCreateRunIfNeeded(const TextFragmentIterator::TextFragment& fragment, Layout::RunVector& runs) |
| { |
| // Adjust end position while collapsing. |
| unsigned endPosition = endPositionForCollapsedFragment(fragment); |
| // New line needs new run. |
| if (!m_runsWidth) { |
| ASSERT(!m_uncompletedWidth); |
| runs.append(Run(fragment.start(), endPosition, m_runsWidth, m_runsWidth + fragment.width(), false, fragment.hasHyphen())); |
| } else { |
| // Advance last completed fragment when the previous fragment is all set (including multiple parts across renderers) |
| if ((m_lastFragment.type() != fragment.type()) || !m_lastFragment.overlapsToNextRenderer()) { |
| m_lastCompleteFragment = m_lastFragment; |
| m_uncompletedWidth = fragment.width(); |
| } else |
| m_uncompletedWidth += fragment.width(); |
| // Collapse neighbouring whitespace, if they are across multiple renderers and are not collapsed yet. |
| if (m_lastFragment.isCollapsible() && fragment.isCollapsible()) { |
| ASSERT(m_lastFragment.isLastInRenderer()); |
| if (!m_lastFragment.isCollapsed()) { |
| // Line width needs to be adjusted so that now it takes collapsing into consideration. |
| m_runsWidth -= (m_lastFragment.width() - m_collapsedWhitespaceWidth); |
| } |
| // This fragment is collapsed completely. No run is needed. |
| return; |
| } |
| if (m_lastFragment.isLastInRenderer() || m_lastFragment.isCollapsed()) |
| runs.append(Run(fragment.start(), endPosition, m_runsWidth, m_runsWidth + fragment.width(), false, fragment.hasHyphen())); |
| else { |
| Run& lastRun = runs.last(); |
| lastRun.end = endPosition; |
| lastRun.logicalRight += fragment.width(); |
| ASSERT(!lastRun.hasHyphen); |
| lastRun.hasHyphen = fragment.hasHyphen(); |
| } |
| } |
| m_runsWidth += fragment.width(); |
| m_lastFragment = fragment; |
| if (m_fragments) |
| (*m_fragments).append(fragment); |
| |
| if (fragment.type() == TextFragmentIterator::TextFragment::Whitespace) { |
| m_trailingWhitespaceWidth += fragment.width(); |
| m_lastWhitespaceFragment = fragment; |
| } else { |
| m_trailingWhitespaceWidth = 0; |
| m_lastNonWhitespaceFragment = fragment; |
| } |
| |
| if (!m_firstCharacterFits) |
| m_firstCharacterFits = fragment.start() + 1 > endPosition || m_runsWidth <= m_availableWidth; |
| } |
| |
| TextFragmentIterator::TextFragment revertToLastCompleteFragment(Layout::RunVector& runs) |
| { |
| if (!m_uncompletedWidth) { |
| ASSERT(m_lastFragment == m_lastCompleteFragment); |
| return m_lastFragment; |
| } |
| ASSERT(m_lastFragment.isValid()); |
| m_runsWidth -= m_uncompletedWidth; |
| revertRuns(runs, endPositionForCollapsedFragment(m_lastCompleteFragment), m_uncompletedWidth); |
| m_uncompletedWidth = 0; |
| ASSERT(m_lastCompleteFragment.isValid()); |
| return m_lastCompleteFragment; |
| } |
| |
| void removeTrailingWhitespace(Layout::RunVector& runs) |
| { |
| if (m_lastFragment.type() != TextFragmentIterator::TextFragment::Whitespace) |
| return; |
| if (m_lastNonWhitespaceFragment) { |
| auto needsReverting = m_lastNonWhitespaceFragment->end() != m_lastFragment.end(); |
| // Trailing whitespace fragment might actually have zero length. |
| ASSERT(needsReverting || !m_trailingWhitespaceWidth); |
| if (needsReverting) { |
| revertRuns(runs, m_lastNonWhitespaceFragment->end(), m_trailingWhitespaceWidth); |
| m_runsWidth -= m_trailingWhitespaceWidth; |
| } |
| m_trailingWhitespaceWidth = 0; |
| m_lastFragment = *m_lastNonWhitespaceFragment; |
| return; |
| } |
| // This line is all whitespace. |
| revertAllRunsOnCurrentLine(runs); |
| m_runsWidth = 0; |
| m_trailingWhitespaceWidth = 0; |
| // FIXME: Make m_lastFragment optional. |
| m_lastFragment = TextFragmentIterator::TextFragment(); |
| } |
| |
| private: |
| bool expansionOpportunity(TextFragmentIterator::TextFragment::Type currentFragmentType, TextFragmentIterator::TextFragment::Type previousFragmentType) const |
| { |
| return (currentFragmentType == TextFragmentIterator::TextFragment::Whitespace |
| || (currentFragmentType == TextFragmentIterator::TextFragment::NonWhitespace && previousFragmentType == TextFragmentIterator::TextFragment::NonWhitespace)); |
| } |
| |
| float m_availableWidth { 0 }; |
| float m_logicalLeftOffset { 0 }; |
| float m_runsWidth { 0 }; |
| TextFragmentIterator::TextFragment m_overflowedFragment; |
| TextFragmentIterator::TextFragment m_lastFragment; |
| Optional<TextFragmentIterator::TextFragment> m_lastNonWhitespaceFragment; |
| Optional<TextFragmentIterator::TextFragment> m_lastWhitespaceFragment; |
| TextFragmentIterator::TextFragment m_lastCompleteFragment; |
| float m_uncompletedWidth { 0 }; |
| float m_trailingWhitespaceWidth { 0 }; // Use this to remove trailing whitespace without re-mesuring the text. |
| float m_collapsedWhitespaceWidth { 0 }; |
| // Having one character on the line does not necessarily mean it actually fits. |
| // First character of the first fragment might be forced on to the current line even if it does not fit. |
| bool m_firstCharacterFits { false }; |
| bool m_hyphenationDisabled { false }; |
| Optional<Vector<TextFragmentIterator::TextFragment, 30>> m_fragments; |
| }; |
| |
| static bool preWrap(const TextFragmentIterator::Style& style) |
| { |
| return style.wrapLines && !style.collapseWhitespace; |
| } |
| |
| static void removeTrailingWhitespace(LineState& lineState, Layout::RunVector& runs, const TextFragmentIterator& textFragmentIterator) |
| { |
| if (!lineState.hasTrailingWhitespace()) |
| return; |
| // Remove collapsed whitespace, or non-collapsed pre-wrap whitespace, unless it's the only content on the line -so removing the whitesapce |
| // would produce an empty line. |
| const auto& style = textFragmentIterator.style(); |
| bool collapseWhitespace = style.collapseWhitespace || (!style.breakSpaces && preWrap(style)); |
| if (!collapseWhitespace) |
| return; |
| if (preWrap(style) && lineState.isWhitespaceOnly()) |
| return; |
| lineState.removeTrailingWhitespace(runs); |
| } |
| |
| static void updateLineConstrains(const RenderBlockFlow& flow, LineState& line, const LineState& previousLine, unsigned& numberOfPrecedingLinesWithHyphen, const TextFragmentIterator::Style& style, bool isFirstLine) |
| { |
| bool shouldApplyTextIndent = !flow.isAnonymous() || flow.parent()->firstChild() == &flow; |
| LayoutUnit height = flow.logicalHeight(); |
| LayoutUnit logicalHeight = flow.minLineHeightForReplacedRenderer(false, 0); |
| line.setLogicalLeftOffset(flow.logicalLeftOffsetForLine(height, DoNotIndentText, logicalHeight) + (shouldApplyTextIndent && isFirstLine ? flow.textIndentOffset() : 0_lu)); |
| float logicalRightOffset = flow.logicalRightOffsetForLine(height, DoNotIndentText, logicalHeight); |
| line.setAvailableWidth(std::max<float>(0, logicalRightOffset - line.logicalLeftOffset())); |
| if (style.textAlign == TextAlignMode::Justify) |
| line.setNeedsAllFragments(); |
| numberOfPrecedingLinesWithHyphen = (previousLine.isEmpty() || !previousLine.lastFragment().hasHyphen()) ? 0 : numberOfPrecedingLinesWithHyphen + 1; |
| if (style.hyphenLimitLines && numberOfPrecedingLinesWithHyphen >= *style.hyphenLimitLines) |
| line.setHyphenationDisabled(); |
| line.setCollapedWhitespaceWidth(style.font.spaceWidth() + style.wordSpacing); |
| } |
| |
| struct SplitFragmentData { |
| unsigned position; |
| float width; |
| }; |
| static Optional<unsigned> hyphenPositionForFragment(SplitFragmentData splitData, const TextFragmentIterator::TextFragment& fragmentToSplit, |
| const LineState& line, const TextFragmentIterator& textFragmentIterator, float availableWidth) |
| { |
| auto& style = textFragmentIterator.style(); |
| if (!style.shouldHyphenate || line.isHyphenationDisabled()) |
| return WTF::nullopt; |
| |
| // FIXME: This is a workaround for webkit.org/b/169613. See maxPrefixWidth computation in tryHyphenating(). |
| // It does not work properly with non-collapsed leading tabs when font is enlarged. |
| auto adjustedAvailableWidth = availableWidth - style.hyphenStringWidth; |
| if (!line.isEmpty()) |
| adjustedAvailableWidth += style.font.spaceWidth(); |
| if (!enoughWidthForHyphenation(adjustedAvailableWidth, style.font.pixelSize())) |
| return WTF::nullopt; |
| |
| // We might be able to fit the hyphen at the split position. |
| auto splitPositionWithHyphen = splitData.position; |
| // Find a splitting position where hyphen surely fits. |
| unsigned start = fragmentToSplit.start(); |
| auto leftSideWidth = splitData.width; |
| while (leftSideWidth + style.hyphenStringWidth > availableWidth) { |
| if (--splitPositionWithHyphen <= start) |
| return WTF::nullopt; // No space for hyphen. |
| leftSideWidth -= textFragmentIterator.textWidth(splitPositionWithHyphen, splitPositionWithHyphen + 1, 0); |
| } |
| ASSERT(splitPositionWithHyphen > start); |
| return textFragmentIterator.lastHyphenPosition(fragmentToSplit, splitPositionWithHyphen + 1); |
| } |
| |
| static SplitFragmentData split(const TextFragmentIterator::TextFragment& fragment, float availableWidth, |
| const TextFragmentIterator& textFragmentIterator) |
| { |
| ASSERT(availableWidth >= 0); |
| auto left = fragment.start(); |
| // Pathological case of (extremely)long string and narrow lines. |
| // Adjust the range so that we can pick a reasonable midpoint. |
| auto averageCharacterWidth = fragment.width() / fragment.length(); |
| auto right = std::min<unsigned>(left + (2 * availableWidth / averageCharacterWidth), fragment.end() - 1); |
| // Preserve the left width for the final split position so that we don't need to remeasure the left side again. |
| float leftSideWidth = 0; |
| while (left < right) { |
| auto middle = (left + right) / 2; |
| auto width = textFragmentIterator.textWidth(fragment.start(), middle + 1, 0); |
| if (width < availableWidth) { |
| left = middle + 1; |
| leftSideWidth = width; |
| } else if (width > availableWidth) |
| right = middle; |
| else { |
| right = middle + 1; |
| leftSideWidth = width; |
| break; |
| } |
| } |
| return { right, leftSideWidth }; |
| } |
| |
| static TextFragmentIterator::TextFragment splitFragmentToFitLine(TextFragmentIterator::TextFragment& fragmentToSplit, |
| const LineState& line, const TextFragmentIterator& textFragmentIterator) |
| { |
| auto availableWidth = line.availableWidth() - line.width(); |
| auto splitFragmentData = split(fragmentToSplit, availableWidth, textFragmentIterator); |
| Optional<unsigned> hyphenPosition = WTF::nullopt; |
| // Does first character fit this line? |
| if (splitFragmentData.position == fragmentToSplit.start()) { |
| // Keep at least one character on empty lines. |
| if (line.isEmpty()) |
| splitFragmentData.width = textFragmentIterator.textWidth(fragmentToSplit.start(), ++splitFragmentData.position, 0); |
| } else { |
| hyphenPosition = hyphenPositionForFragment(splitFragmentData, fragmentToSplit, line, textFragmentIterator, availableWidth); |
| if (hyphenPosition) { |
| splitFragmentData.position = *hyphenPosition; |
| splitFragmentData.width = textFragmentIterator.textWidth(fragmentToSplit.start(), splitFragmentData.position, 0); |
| } |
| } |
| // If the right side surely does not fit the (next)line, we don't need the width to be kerning/ligature adjusted. |
| // Part of it gets re-measured as the left side during next split. |
| // This saves measuring long chunk of text repeatedly (see pathological case at ::split). |
| auto rightSideWidth = fragmentToSplit.width() - splitFragmentData.width; |
| if (rightSideWidth < 2 * availableWidth) |
| rightSideWidth = textFragmentIterator.textWidth(splitFragmentData.position, fragmentToSplit.end(), 0); |
| return hyphenPosition ? fragmentToSplit.splitWithHyphen(splitFragmentData.position, textFragmentIterator.style().hyphenStringWidth, |
| splitFragmentData.width, rightSideWidth) : fragmentToSplit.split(splitFragmentData.position, splitFragmentData.width, rightSideWidth); |
| } |
| |
| enum PreWrapLineBreakRule { Preserve, Ignore }; |
| |
| static TextFragmentIterator::TextFragment consumeLineBreakIfNeeded(const TextFragmentIterator::TextFragment& fragment, TextFragmentIterator& textFragmentIterator, LineState& line, Layout::RunVector& runs, |
| PreWrapLineBreakRule preWrapLineBreakRule = PreWrapLineBreakRule::Preserve) |
| { |
| if (!fragment.isLineBreak()) |
| return fragment; |
| |
| bool isHardLinebreak = fragment.type() == TextFragmentIterator::TextFragment::HardLineBreak; |
| // <br> always produces a run. (required by testing output) |
| if (isHardLinebreak) |
| line.appendFragmentAndCreateRunIfNeeded(fragment, runs); |
| |
| auto& style = textFragmentIterator.style(); |
| if (style.preserveNewline && preWrapLineBreakRule == PreWrapLineBreakRule::Preserve) { |
| if (!isHardLinebreak) |
| return fragment; |
| } |
| return textFragmentIterator.nextTextFragment(); |
| } |
| |
| static TextFragmentIterator::TextFragment skipWhitespaceIfNeeded(const TextFragmentIterator::TextFragment& fragment, TextFragmentIterator& textFragmentIterator) |
| { |
| if (!textFragmentIterator.style().collapseWhitespace) |
| return fragment; |
| |
| TextFragmentIterator::TextFragment firstNonWhitespaceFragment = fragment; |
| while (firstNonWhitespaceFragment.type() == TextFragmentIterator::TextFragment::Whitespace) |
| firstNonWhitespaceFragment = textFragmentIterator.nextTextFragment(); |
| return firstNonWhitespaceFragment; |
| } |
| |
| static TextFragmentIterator::TextFragment firstFragment(TextFragmentIterator& textFragmentIterator, LineState& currentLine, const LineState& previousLine, Layout::RunVector& runs) |
| { |
| // Handle overflow fragment from previous line. |
| auto overflowedFragment = previousLine.overflowedFragment(); |
| if (overflowedFragment.isEmpty()) |
| return skipWhitespaceIfNeeded(textFragmentIterator.nextTextFragment(), textFragmentIterator); |
| |
| if (overflowedFragment.type() != TextFragmentIterator::TextFragment::Whitespace) |
| return overflowedFragment; |
| |
| // Leading whitespace handling. |
| auto& style = textFragmentIterator.style(); |
| if (style.breakSpaces) { |
| // Leading whitespace created after breaking the previous line. |
| // Breaking before the first space after a word is only allowed in combination with break-all or break-word. |
| if (style.breakFirstWordOnOverflow || previousLine.hasTrailingWhitespace()) |
| return overflowedFragment; |
| } |
| // Special overflow pre-wrap whitespace handling: skip the overflowed whitespace (even when style says not-collapsible) |
| // if we manage to fit at least one character on the previous line. |
| auto preWrapIsOn = preWrap(style); |
| if ((style.collapseWhitespace || preWrapIsOn) && previousLine.firstCharacterFits()) { |
| // If skipping the whitespace puts us on a newline, skip the newline too as we already wrapped the line. |
| auto firstFragmentCandidate = consumeLineBreakIfNeeded(textFragmentIterator.nextTextFragment(), textFragmentIterator, currentLine, runs, |
| preWrapIsOn ? PreWrapLineBreakRule::Ignore : PreWrapLineBreakRule::Preserve); |
| return skipWhitespaceIfNeeded(firstFragmentCandidate, textFragmentIterator); |
| } |
| return skipWhitespaceIfNeeded(overflowedFragment, textFragmentIterator); |
| } |
| |
| static void forceFragmentToLine(LineState& line, TextFragmentIterator& textFragmentIterator, Layout::RunVector& runs, const TextFragmentIterator::TextFragment& fragment) |
| { |
| line.appendFragmentAndCreateRunIfNeeded(fragment, runs); |
| // Check if there are more fragments to add to the current line. |
| auto nextFragment = textFragmentIterator.nextTextFragment(); |
| if (fragment.overlapsToNextRenderer()) { |
| while (true) { |
| if (nextFragment.type() != fragment.type()) |
| break; |
| line.appendFragmentAndCreateRunIfNeeded(nextFragment, runs); |
| // Does it overlap to the next segment? |
| if (!nextFragment.overlapsToNextRenderer()) |
| return; |
| nextFragment = textFragmentIterator.nextTextFragment(); |
| } |
| } |
| // When the forced fragment is followed by either whitespace and/or line break, consume them too, otherwise we end up with an extra whitespace and/or line break. |
| nextFragment = skipWhitespaceIfNeeded(nextFragment, textFragmentIterator); |
| nextFragment = consumeLineBreakIfNeeded(nextFragment, textFragmentIterator, line, runs); |
| line.setOverflowedFragment(nextFragment); |
| } |
| |
| static bool createLineRuns(LineState& line, const LineState& previousLine, Layout::RunVector& runs, TextFragmentIterator& textFragmentIterator) |
| { |
| const auto& style = textFragmentIterator.style(); |
| bool lineCanBeWrapped = style.wrapLines || style.breakFirstWordOnOverflow || style.breakAnyWordOnOverflow; |
| auto fragment = firstFragment(textFragmentIterator, line, previousLine, runs); |
| while (fragment.type() != TextFragmentIterator::TextFragment::ContentEnd) { |
| // Hard and soft linebreaks. |
| if (fragment.isLineBreak()) { |
| // Add the new line fragment only if there's nothing on the line. (otherwise the extra new line character would show up at the end of the content.) |
| if (line.isEmpty() || fragment.type() == TextFragmentIterator::TextFragment::HardLineBreak) { |
| if (style.textAlign == TextAlignMode::Right || style.textAlign == TextAlignMode::WebKitRight) |
| line.removeTrailingWhitespace(runs); |
| line.appendFragmentAndCreateRunIfNeeded(fragment, runs); |
| } |
| break; |
| } |
| if (lineCanBeWrapped && !line.fits(fragment.width())) { |
| // Overflow wrapping behaviour: |
| // 1. Whitesapce collapse on: whitespace is skipped. Jump to next line. |
| // 2. Whitespace collapse off: whitespace is wrapped. |
| // 3. First, non-whitespace fragment is either wrapped or kept on the line. (depends on overflow-wrap) |
| // 5. Non-whitespace fragment when there's already another fragment on the line either gets wrapped (word-break: break-all) |
| // or gets pushed to the next line. |
| bool emptyLine = line.isEmpty(); |
| // Whitespace fragment. |
| if (fragment.type() == TextFragmentIterator::TextFragment::Whitespace) { |
| if (style.collapseWhitespace) { |
| // Push collapased whitespace to the next line. |
| line.setOverflowedFragment(fragment); |
| break; |
| } |
| if (style.breakSpaces && line.hasWhitespaceFragments() && fragment.length() == 1) { |
| // Breaking before the first space after a word is not allowed if there are previous breaking opportunities in the line. |
| textFragmentIterator.revertToEndOfFragment(line.revertToLastCompleteFragment(runs)); |
| break; |
| } |
| // Split the whitespace; left part stays on this line, right is pushed to next line. |
| line.setOverflowedFragment(splitFragmentToFitLine(fragment, line, textFragmentIterator)); |
| line.appendFragmentAndCreateRunIfNeeded(fragment, runs); |
| break; |
| } |
| // Non-whitespace fragment. (!style.wrapLines: bug138102(preserve existing behavior) |
| if (((emptyLine && style.breakFirstWordOnOverflow) || style.breakAnyWordOnOverflow) || !style.wrapLines) { |
| // Split the fragment; (modified)fragment stays on this line, overflowedFragment is pushed to next line. |
| line.setOverflowedFragment(splitFragmentToFitLine(fragment, line, textFragmentIterator)); |
| line.appendFragmentAndCreateRunIfNeeded(fragment, runs); |
| break; |
| } |
| ASSERT(fragment.type() == TextFragmentIterator::TextFragment::NonWhitespace); |
| // Find out if this non-whitespace fragment has a hyphen where we can break. |
| if (style.shouldHyphenate) { |
| auto fragmentToSplit = fragment; |
| // Split and check if we actually ended up with a hyphen. |
| auto overflowFragment = splitFragmentToFitLine(fragmentToSplit, line, textFragmentIterator); |
| if (fragmentToSplit.hasHyphen()) { |
| line.setOverflowedFragment(overflowFragment); |
| line.appendFragmentAndCreateRunIfNeeded(fragmentToSplit, runs); |
| break; |
| } |
| // No hyphen, no split. |
| } |
| // Non-breakable non-whitespace first fragment. Add it to the current line. -it overflows though. |
| if (emptyLine) { |
| forceFragmentToLine(line, textFragmentIterator, runs, fragment); |
| break; |
| } |
| // Non-breakable non-whitespace fragment when there's already content on the line. Push it to the next line. |
| ASSERT(line.lastFragment().isValid()); |
| if (line.lastFragment().overlapsToNextRenderer()) { |
| // Check if this fragment is a continuation of a previous segment. In such cases, we need to remove them all. |
| textFragmentIterator.revertToEndOfFragment(line.revertToLastCompleteFragment(runs)); |
| break; |
| } |
| line.setOverflowedFragment(fragment); |
| break; |
| } |
| line.appendFragmentAndCreateRunIfNeeded(fragment, runs); |
| // Find the next text fragment. |
| fragment = textFragmentIterator.nextTextFragment(line.width()); |
| } |
| return (fragment.type() == TextFragmentIterator::TextFragment::ContentEnd && line.overflowedFragment().isEmpty()) || line.overflowedFragment().type() == TextFragmentIterator::TextFragment::ContentEnd; |
| } |
| |
| static ExpansionBehavior expansionBehavior(bool isAfterExpansion, bool lastRunOnLine) |
| { |
| ExpansionBehavior expansionBehavior; |
| expansionBehavior = isAfterExpansion ? ForbidLeadingExpansion : AllowLeadingExpansion; |
| expansionBehavior |= lastRunOnLine ? ForbidTrailingExpansion : AllowTrailingExpansion; |
| return expansionBehavior; |
| } |
| |
| static void justifyRuns(const LineState& line, Layout::RunVector& runs, unsigned firstRunIndex) |
| { |
| ASSERT(runs.size()); |
| auto widthToDistribute = line.availableWidth() - line.width(); |
| if (widthToDistribute <= 0) |
| return; |
| |
| auto lastRunIndex = runs.size() - 1; |
| ASSERT(firstRunIndex <= lastRunIndex); |
| Vector<std::pair<unsigned, ExpansionBehavior>> expansionOpportunityList; |
| unsigned expansionOpportunityCountOnThisLine = 0; |
| auto isAfterExpansion = true; |
| for (auto i = firstRunIndex; i <= lastRunIndex; ++i) { |
| const auto& run = runs.at(i); |
| unsigned opportunityCountInRun = 0; |
| std::tie(opportunityCountInRun, isAfterExpansion) = line.expansionOpportunityCount(run.start, run.end); |
| expansionOpportunityList.append(std::make_pair(opportunityCountInRun, expansionBehavior(isAfterExpansion, i == lastRunIndex))); |
| expansionOpportunityCountOnThisLine += opportunityCountInRun; |
| } |
| if (!expansionOpportunityCountOnThisLine) |
| return; |
| |
| ASSERT(expansionOpportunityList.size() == lastRunIndex - firstRunIndex + 1); |
| auto expansion = widthToDistribute / expansionOpportunityCountOnThisLine; |
| float accumulatedExpansion = 0; |
| for (auto i = firstRunIndex; i <= lastRunIndex; ++i) { |
| auto& run = runs.at(i); |
| unsigned opportunityCountInRun; |
| std::tie(opportunityCountInRun, run.expansionBehavior) = expansionOpportunityList.at(i - firstRunIndex); |
| run.expansion = opportunityCountInRun * expansion; |
| run.logicalLeft += accumulatedExpansion; |
| run.logicalRight += (accumulatedExpansion + run.expansion); |
| accumulatedExpansion += run.expansion; |
| } |
| } |
| |
| static TextAlignMode textAlignForLine(const TextFragmentIterator::Style& style, bool lastLine) |
| { |
| // Fallback to TextAlignMode::Left (START) alignment for non-collapsable content and for the last line before a forced break or the end of the block. |
| auto textAlign = style.textAlign; |
| if (textAlign == TextAlignMode::Justify && (!style.collapseWhitespace || lastLine)) |
| textAlign = TextAlignMode::Left; |
| return textAlign; |
| } |
| |
| static void closeLineEndingAndAdjustRuns(LineState& line, Layout::RunVector& runs, Optional<unsigned> lastRunIndexOfPreviousLine, unsigned& lineCount, |
| const TextFragmentIterator& textFragmentIterator, bool lastLineInFlow) |
| { |
| if (!runs.size() || (lastRunIndexOfPreviousLine && runs.size() - 1 == lastRunIndexOfPreviousLine.value())) |
| return; |
| removeTrailingWhitespace(line, runs, textFragmentIterator); |
| if (!runs.size()) |
| return; |
| // Adjust runs' position by taking line's alignment into account. |
| const auto& style = textFragmentIterator.style(); |
| auto firstRunIndex = lastRunIndexOfPreviousLine ? lastRunIndexOfPreviousLine.value() + 1 : 0; |
| auto lineLogicalLeft = line.logicalLeftOffset(); |
| auto textAlign = textAlignForLine(style, lastLineInFlow || (line.lastFragment().isValid() && line.lastFragment().type() == TextFragmentIterator::TextFragment::HardLineBreak)); |
| if (textAlign == TextAlignMode::Justify) |
| justifyRuns(line, runs, firstRunIndex); |
| else |
| lineLogicalLeft = computeLineLeft(textAlign, line.availableWidth(), line.width(), line.logicalLeftOffset()); |
| for (auto i = firstRunIndex; i < runs.size(); ++i) { |
| runs[i].logicalLeft += lineLogicalLeft; |
| runs[i].logicalRight += lineLogicalLeft; |
| } |
| runs.last().isEndOfLine = true; |
| ++lineCount; |
| } |
| |
| static void createTextRuns(Layout::RunVector& runs, RenderBlockFlow& flow, unsigned& lineCount) |
| { |
| LayoutUnit borderAndPaddingBefore = flow.borderAndPaddingBefore(); |
| LayoutUnit lineHeight = lineHeightFromFlow(flow); |
| LineState line; |
| unsigned numberOfPrecedingLinesWithHyphen = 0; |
| bool isEndOfContent = false; |
| TextFragmentIterator textFragmentIterator = TextFragmentIterator(flow); |
| Optional<unsigned> lastRunIndexOfPreviousLine; |
| do { |
| flow.setLogicalHeight(lineHeight * lineCount + borderAndPaddingBefore); |
| LineState previousLine = line; |
| line = LineState(); |
| updateLineConstrains(flow, line, previousLine, numberOfPrecedingLinesWithHyphen, textFragmentIterator.style(), !lineCount); |
| isEndOfContent = createLineRuns(line, previousLine, runs, textFragmentIterator); |
| closeLineEndingAndAdjustRuns(line, runs, lastRunIndexOfPreviousLine, lineCount, textFragmentIterator, isEndOfContent); |
| if (runs.size()) |
| lastRunIndexOfPreviousLine = runs.size() - 1; |
| } while (!isEndOfContent); |
| } |
| |
| std::unique_ptr<Layout> create(RenderBlockFlow& flow) |
| { |
| unsigned lineCount = 0; |
| Layout::RunVector runs; |
| createTextRuns(runs, flow, lineCount); |
| return Layout::create(runs, lineCount, flow); |
| } |
| |
| std::unique_ptr<Layout> Layout::create(const RunVector& runVector, unsigned lineCount, const RenderBlockFlow& blockFlow) |
| { |
| void* slot = WTF::fastMalloc(sizeof(Layout) + sizeof(Run) * runVector.size()); |
| return std::unique_ptr<Layout>(new (NotNull, slot) Layout(runVector, lineCount, blockFlow)); |
| } |
| |
| Layout::Layout(const RunVector& runVector, unsigned lineCount, const RenderBlockFlow& blockFlow) |
| : m_lineCount(lineCount) |
| , m_runCount(runVector.size()) |
| , m_blockFlowRenderer(blockFlow) |
| { |
| memcpy(m_runs, runVector.data(), m_runCount * sizeof(Run)); |
| } |
| |
| const RunResolver& Layout::runResolver() const |
| { |
| if (!m_runResolver) |
| m_runResolver = std::make_unique<RunResolver>(m_blockFlowRenderer, *this); |
| return *m_runResolver; |
| } |
| |
| Layout::~Layout() |
| { |
| simpleLineLayoutWillBeDeleted(*this); |
| } |
| |
| } |
| } |
