| /* |
| * Copyright (C) 2019 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 "InlineLine.h" |
| |
| #if ENABLE(LAYOUT_FORMATTING_CONTEXT) |
| |
| #include "InlineFormattingContext.h" |
| #include "TextUtil.h" |
| #include <wtf/IsoMallocInlines.h> |
| |
| namespace WebCore { |
| namespace Layout { |
| |
| WTF_MAKE_ISO_ALLOCATED_IMPL(Line); |
| |
| Line::Run::Run(const InlineItem& inlineItem, const Display::Run& displayRun) |
| : m_inlineItem(inlineItem) |
| , m_displayRun(displayRun) |
| { |
| } |
| |
| bool Line::Run::isWhitespace() const |
| { |
| if (!isText()) |
| return false; |
| return downcast<InlineTextItem>(m_inlineItem).isWhitespace(); |
| } |
| |
| bool Line::Run::canBeExtended() const |
| { |
| if (!isText()) |
| return false; |
| return !downcast<InlineTextItem>(m_inlineItem).isCollapsed() && !isVisuallyEmpty(); |
| } |
| |
| Line::Line(const InlineFormattingContext& inlineFormattingContext, const InitialConstraints& initialConstraints, Optional<TextAlignMode> horizontalAlignment, SkipAlignment skipAlignment) |
| : m_inlineFormattingContext(inlineFormattingContext) |
| , m_initialStrut(initialConstraints.heightAndBaseline ? initialConstraints.heightAndBaseline->strut : WTF::nullopt) |
| , m_lineLogicalWidth(initialConstraints.availableLogicalWidth) |
| , m_horizontalAlignment(horizontalAlignment) |
| , m_skipAlignment(skipAlignment == SkipAlignment::Yes) |
| { |
| ASSERT(m_skipAlignment || initialConstraints.heightAndBaseline); |
| auto initialLineHeight = initialConstraints.heightAndBaseline ? initialConstraints.heightAndBaseline->height : LayoutUnit(); |
| auto initialBaselineOffset = initialConstraints.heightAndBaseline ? initialConstraints.heightAndBaseline->baselineOffset : LayoutUnit(); |
| auto lineRect = Display::Rect { initialConstraints.logicalTopLeft, { }, initialLineHeight }; |
| auto baseline = LineBox::Baseline { initialBaselineOffset, initialLineHeight - initialBaselineOffset }; |
| m_lineBox = LineBox { lineRect, baseline, { } }; |
| } |
| |
| static bool isInlineContainerConsideredEmpty(const FormattingContext& formattingContext, const Box& layoutBox) |
| { |
| // Note that this does not check whether the inline container has content. It simply checks if the container itself is considered empty. |
| auto& boxGeometry = formattingContext.geometryForBox(layoutBox); |
| return !(boxGeometry.horizontalBorder() || (boxGeometry.horizontalPadding() && boxGeometry.horizontalPadding().value())); |
| } |
| |
| bool Line::isVisuallyEmpty() const |
| { |
| // FIXME: This should be cached instead -as the inline items are being added. |
| // Return true for empty inline containers like <span></span>. |
| auto& formattingContext = this->formattingContext(); |
| for (auto& run : m_runList) { |
| if (run->isContainerStart()) { |
| if (!isInlineContainerConsideredEmpty(formattingContext, run->layoutBox())) |
| return false; |
| continue; |
| } |
| if (run->isContainerEnd()) |
| continue; |
| if (run->layoutBox().establishesFormattingContext()) { |
| ASSERT(run->layoutBox().isInlineBlockBox()); |
| auto& boxGeometry = formattingContext.geometryForBox(run->layoutBox()); |
| if (!boxGeometry.width()) |
| continue; |
| if (m_skipAlignment || boxGeometry.height()) |
| return false; |
| continue; |
| } |
| if (!run->isText() || !run->isVisuallyEmpty()) |
| return false; |
| } |
| return true; |
| } |
| |
| Line::RunList Line::close() |
| { |
| removeTrailingTrimmableContent(); |
| // Join text runs together when possible. |
| unsigned index = 1; |
| while (index < m_runList.size()) { |
| auto& previousRun = m_runList[index - 1]; |
| if (!previousRun->canBeExtended()) { |
| ++index; |
| continue; |
| } |
| auto& currentRun = m_runList[index]; |
| if (¤tRun->layoutBox() != &previousRun->layoutBox()) { |
| // Do not merge runs from different boxes (<span>foo</span><span>bar</span>). |
| ++index; |
| continue; |
| } |
| // Only text content can be extended atm. |
| ASSERT(previousRun->isText()); |
| ASSERT(currentRun->isText()); |
| previousRun->expand(*currentRun); |
| m_runList.remove(index); |
| } |
| |
| if (!m_skipAlignment) { |
| alignContentVertically(); |
| alignContentHorizontally(); |
| } |
| |
| return WTFMove(m_runList); |
| } |
| |
| void Line::alignContentVertically() |
| { |
| ASSERT(!m_skipAlignment); |
| |
| if (isVisuallyEmpty()) { |
| m_lineBox.baseline().reset(); |
| m_lineBox.setBaselineOffset({ }); |
| m_lineBox.setLogicalHeight({ }); |
| } |
| |
| // Remove descent when all content is baseline aligned but none of them have descent. |
| if (formattingContext().quirks().lineDescentNeedsCollapsing(m_runList)) { |
| m_lineBox.shrinkVertically(m_lineBox.baseline().descent()); |
| m_lineBox.baseline().setDescent({ }); |
| } |
| |
| auto& layoutState = this->layoutState(); |
| auto& formattingContext = this->formattingContext(); |
| for (auto& run : m_runList) { |
| LayoutUnit logicalTop; |
| auto& layoutBox = run->layoutBox(); |
| auto verticalAlign = layoutBox.style().verticalAlign(); |
| auto ascent = layoutBox.style().fontMetrics().ascent(); |
| |
| switch (verticalAlign) { |
| case VerticalAlign::Baseline: |
| if (run->isLineBreak() || run->isText()) |
| logicalTop = baselineOffset() - ascent; |
| else if (run->isContainerStart()) { |
| auto& boxGeometry = formattingContext.geometryForBox(layoutBox); |
| logicalTop = baselineOffset() - ascent - boxGeometry.borderTop() - boxGeometry.paddingTop().valueOr(0); |
| } else if (layoutBox.isInlineBlockBox() && layoutBox.establishesInlineFormattingContext()) { |
| auto& formattingState = downcast<InlineFormattingState>(layoutState.establishedFormattingState(downcast<Container>(layoutBox))); |
| // Spec makes us generate at least one line -even if it is empty. |
| ASSERT(!formattingState.lineBoxes().isEmpty()); |
| auto inlineBlockBaseline = formattingState.lineBoxes().last().baseline(); |
| logicalTop = baselineOffset() - inlineBlockBaseline.ascent(); |
| } else |
| logicalTop = baselineOffset() - run->logicalRect().height(); |
| break; |
| case VerticalAlign::Top: |
| logicalTop = { }; |
| break; |
| case VerticalAlign::Bottom: |
| logicalTop = logicalBottom() - run->logicalRect().height(); |
| break; |
| default: |
| ASSERT_NOT_IMPLEMENTED_YET(); |
| break; |
| } |
| run->adjustLogicalTop(logicalTop); |
| // Convert runs from relative to the line top/left to the formatting root's border box top/left. |
| run->moveVertically(this->logicalTop()); |
| run->moveHorizontally(this->logicalLeft()); |
| } |
| } |
| |
| void Line::alignContentHorizontally() |
| { |
| ASSERT(!m_skipAlignment); |
| |
| auto adjustmentForAlignment = [&]() -> Optional<LayoutUnit> { |
| switch (*m_horizontalAlignment) { |
| case TextAlignMode::Left: |
| case TextAlignMode::WebKitLeft: |
| case TextAlignMode::Start: |
| return { }; |
| case TextAlignMode::Right: |
| case TextAlignMode::WebKitRight: |
| case TextAlignMode::End: |
| return std::max(availableWidth(), 0_lu); |
| case TextAlignMode::Center: |
| case TextAlignMode::WebKitCenter: |
| return std::max(availableWidth() / 2, 0_lu); |
| case TextAlignMode::Justify: |
| ASSERT_NOT_REACHED(); |
| break; |
| } |
| ASSERT_NOT_REACHED(); |
| return { }; |
| }; |
| |
| auto adjustment = adjustmentForAlignment(); |
| if (!adjustment) |
| return; |
| |
| for (auto& run : m_runList) |
| run->moveHorizontally(*adjustment); |
| // FIXME: Find out if m_lineBox needs adjustmnent as well. |
| } |
| |
| void Line::removeTrailingTrimmableContent() |
| { |
| // Collapse trimmable trailing content |
| LayoutUnit trimmableWidth; |
| for (auto* trimmableRun : m_trimmableContent) { |
| ASSERT(trimmableRun->isText()); |
| trimmableRun->setVisuallyIsEmpty(); |
| trimmableWidth += trimmableRun->logicalRect().width(); |
| } |
| m_lineBox.shrinkHorizontally(trimmableWidth); |
| } |
| |
| void Line::moveLogicalLeft(LayoutUnit delta) |
| { |
| if (!delta) |
| return; |
| ASSERT(delta > 0); |
| m_lineBox.moveHorizontally(delta); |
| m_lineLogicalWidth -= delta; |
| } |
| |
| void Line::moveLogicalRight(LayoutUnit delta) |
| { |
| ASSERT(delta > 0); |
| m_lineLogicalWidth -= delta; |
| } |
| |
| LayoutUnit Line::trailingTrimmableWidth() const |
| { |
| LayoutUnit trimmableWidth; |
| for (auto* trimmableRun : m_trimmableContent) { |
| ASSERT(!trimmableRun->isVisuallyEmpty()); |
| trimmableWidth += trimmableRun->logicalRect().width(); |
| } |
| return trimmableWidth; |
| } |
| |
| void Line::append(const InlineItem& inlineItem, LayoutUnit logicalWidth) |
| { |
| if (inlineItem.isHardLineBreak()) |
| return appendHardLineBreak(inlineItem); |
| if (is<InlineTextItem>(inlineItem)) |
| return appendTextContent(downcast<InlineTextItem>(inlineItem), logicalWidth); |
| if (inlineItem.isContainerStart()) |
| return appendInlineContainerStart(inlineItem, logicalWidth); |
| if (inlineItem.isContainerEnd()) |
| return appendInlineContainerEnd(inlineItem, logicalWidth); |
| if (inlineItem.layoutBox().replaced()) |
| return appendReplacedInlineBox(inlineItem, logicalWidth); |
| appendNonReplacedInlineBox(inlineItem, logicalWidth); |
| } |
| |
| void Line::appendNonBreakableSpace(const InlineItem& inlineItem, const Display::Rect& logicalRect) |
| { |
| m_runList.append(makeUnique<Run>(inlineItem, Display::Run { logicalRect })); |
| m_lineBox.expandHorizontally(logicalRect.width()); |
| } |
| |
| void Line::appendInlineContainerStart(const InlineItem& inlineItem, LayoutUnit logicalWidth) |
| { |
| auto logicalRect = Display::Rect { }; |
| logicalRect.setLeft(contentLogicalWidth()); |
| logicalRect.setWidth(logicalWidth); |
| |
| if (!m_skipAlignment) { |
| auto logicalHeight = inlineItemContentHeight(inlineItem); |
| adjustBaselineAndLineHeight(inlineItem, logicalHeight); |
| logicalRect.setHeight(logicalHeight); |
| } |
| appendNonBreakableSpace(inlineItem, logicalRect); |
| } |
| |
| void Line::appendInlineContainerEnd(const InlineItem& inlineItem, LayoutUnit logicalWidth) |
| { |
| // This is really just a placeholder to mark the end of the inline level container. |
| auto logicalRect = Display::Rect { 0, contentLogicalRight(), logicalWidth, 0 }; |
| appendNonBreakableSpace(inlineItem, logicalRect); |
| } |
| |
| void Line::appendTextContent(const InlineTextItem& inlineItem, LayoutUnit logicalWidth) |
| { |
| auto isTrimmable = TextUtil::isTrimmableContent(inlineItem); |
| if (!isTrimmable) |
| m_trimmableContent.clear(); |
| |
| auto willCollapseCompletely = [&] { |
| // Empty run. |
| if (!inlineItem.length()) { |
| ASSERT(!logicalWidth); |
| return true; |
| } |
| if (!isTrimmable) |
| return false; |
| // Leading whitespace. |
| if (m_runList.isEmpty()) |
| return true; |
| // Check if the last item is trimmable as well. |
| for (int index = m_runList.size() - 1; index >= 0; --index) { |
| auto& run = m_runList[index]; |
| if (run->isBox()) |
| return false; |
| if (run->isText()) |
| return run->isWhitespace() && run->layoutBox().style().collapseWhiteSpace(); |
| ASSERT(run->isContainerStart() || run->isContainerEnd()); |
| } |
| return true; |
| }; |
| |
| auto logicalRect = Display::Rect { }; |
| logicalRect.setLeft(contentLogicalWidth()); |
| logicalRect.setWidth(logicalWidth); |
| if (!m_skipAlignment) { |
| auto runHeight = inlineItemContentHeight(inlineItem); |
| logicalRect.setHeight(runHeight); |
| adjustBaselineAndLineHeight(inlineItem, runHeight); |
| } |
| |
| auto lineItem = makeUnique<Run>(inlineItem, Display::Run { logicalRect, Display::Run::TextContext { inlineItem.start(), inlineItem.isCollapsed() ? 1 : inlineItem.length() } }); |
| auto isVisuallyEmpty = willCollapseCompletely(); |
| if (isVisuallyEmpty) |
| lineItem->setVisuallyIsEmpty(); |
| else if (isTrimmable) |
| m_trimmableContent.add(lineItem.get()); |
| |
| m_runList.append(WTFMove(lineItem)); |
| // Collapsed line items don't contribute to the line width. |
| if (!isVisuallyEmpty) |
| m_lineBox.expandHorizontally(logicalWidth); |
| } |
| |
| void Line::appendNonReplacedInlineBox(const InlineItem& inlineItem, LayoutUnit logicalWidth) |
| { |
| auto& boxGeometry = formattingContext().geometryForBox(inlineItem.layoutBox()); |
| auto horizontalMargin = boxGeometry.horizontalMargin(); |
| auto logicalRect = Display::Rect { }; |
| |
| logicalRect.setLeft(contentLogicalWidth() + horizontalMargin.start); |
| logicalRect.setWidth(logicalWidth); |
| if (!m_skipAlignment) { |
| adjustBaselineAndLineHeight(inlineItem, boxGeometry.marginBoxHeight()); |
| logicalRect.setHeight(inlineItemContentHeight(inlineItem)); |
| } |
| |
| m_runList.append(makeUnique<Run>(inlineItem, Display::Run { logicalRect })); |
| m_lineBox.expandHorizontally(logicalWidth + horizontalMargin.start + horizontalMargin.end); |
| m_trimmableContent.clear(); |
| } |
| |
| void Line::appendReplacedInlineBox(const InlineItem& inlineItem, LayoutUnit logicalWidth) |
| { |
| // FIXME Surely replaced boxes behave differently. |
| appendNonReplacedInlineBox(inlineItem, logicalWidth); |
| } |
| |
| void Line::appendHardLineBreak(const InlineItem& inlineItem) |
| { |
| auto logicalRect = Display::Rect { }; |
| logicalRect.setLeft(contentLogicalWidth()); |
| logicalRect.setWidth({ }); |
| if (!m_skipAlignment) { |
| adjustBaselineAndLineHeight(inlineItem, { }); |
| logicalRect.setHeight(logicalHeight()); |
| } |
| m_runList.append(makeUnique<Run>(inlineItem, Display::Run { logicalRect })); |
| } |
| |
| void Line::adjustBaselineAndLineHeight(const InlineItem& inlineItem, LayoutUnit runHeight) |
| { |
| ASSERT(!inlineItem.isContainerEnd()); |
| auto& layoutBox = inlineItem.layoutBox(); |
| auto& style = layoutBox.style(); |
| auto& baseline = m_lineBox.baseline(); |
| |
| if (inlineItem.isContainerStart()) { |
| // Inline containers stretch the line by their font size. |
| // Vertical margins, paddings and borders don't contribute to the line height. |
| auto& fontMetrics = style.fontMetrics(); |
| LayoutUnit contentHeight; |
| if (style.verticalAlign() == VerticalAlign::Baseline) { |
| auto halfLeading = halfLeadingMetrics(fontMetrics, style.computedLineHeight()); |
| // Both halfleading ascent and descent could be negative (tall font vs. small line-height value) |
| if (halfLeading.descent() > 0) |
| baseline.setDescentIfGreater(halfLeading.descent()); |
| if (halfLeading.ascent() > 0) |
| baseline.setAscentIfGreater(halfLeading.ascent()); |
| contentHeight = baseline.height(); |
| } else |
| contentHeight = fontMetrics.height(); |
| m_lineBox.setLogicalHeightIfGreater(contentHeight, LineBox::AdjustBaseline::Yes); |
| return; |
| } |
| |
| if (inlineItem.isText() || inlineItem.isHardLineBreak()) { |
| // For text content we set the baseline either through the initial strut (set by the formatting context root) or |
| // through the inline container (start) -see above. Normally the text content itself does not stretch the line. |
| if (!m_initialStrut) |
| return; |
| baseline.setAscentIfGreater(m_initialStrut->ascent()); |
| baseline.setDescentIfGreater(m_initialStrut->descent()); |
| m_lineBox.setLogicalHeightIfGreater(baseline.height(), LineBox::AdjustBaseline::Yes); |
| m_initialStrut = { }; |
| return; |
| } |
| |
| if (inlineItem.isBox()) { |
| switch (style.verticalAlign()) { |
| case VerticalAlign::Baseline: { |
| auto newBaselineCandidate = LineBox::Baseline { runHeight, 0 }; |
| if (layoutBox.isInlineBlockBox() && layoutBox.establishesInlineFormattingContext()) { |
| // Inline-blocks with inline content always have baselines. |
| auto& formattingState = downcast<InlineFormattingState>(layoutState().establishedFormattingState(downcast<Container>(layoutBox))); |
| // Spec makes us generate at least one line -even if it is empty. |
| ASSERT(!formattingState.lineBoxes().isEmpty()); |
| newBaselineCandidate = formattingState.lineBoxes().last().baseline(); |
| } |
| baseline.setAscentIfGreater(newBaselineCandidate.ascent()); |
| baseline.setDescentIfGreater(newBaselineCandidate.descent()); |
| m_lineBox.setLogicalHeightIfGreater(std::max(runHeight, baseline.height()), LineBox::AdjustBaseline::Yes); |
| break; |
| } |
| case VerticalAlign::Top: |
| // Top align content never changes the baseline offset, it only pushes the bottom of the line further down. |
| m_lineBox.setLogicalHeightIfGreater(runHeight, LineBox::AdjustBaseline::No); |
| break; |
| case VerticalAlign::Bottom: |
| // Bottom aligned, tall content pushes the baseline further down from the line top. |
| m_lineBox.setLogicalHeightIfGreater(runHeight, LineBox::AdjustBaseline::Yes); |
| break; |
| default: |
| ASSERT_NOT_IMPLEMENTED_YET(); |
| break; |
| } |
| return; |
| } |
| ASSERT_NOT_REACHED(); |
| } |
| |
| LayoutUnit Line::inlineItemContentHeight(const InlineItem& inlineItem) const |
| { |
| ASSERT(!m_skipAlignment); |
| auto& fontMetrics = inlineItem.style().fontMetrics(); |
| if (inlineItem.isLineBreak() || is<InlineTextItem>(inlineItem)) |
| return fontMetrics.height(); |
| |
| auto& layoutBox = inlineItem.layoutBox(); |
| auto& boxGeometry = formattingContext().geometryForBox(layoutBox); |
| |
| if (layoutBox.isFloatingPositioned()) |
| return boxGeometry.borderBoxHeight(); |
| |
| if (layoutBox.replaced()) |
| return boxGeometry.borderBoxHeight(); |
| |
| if (inlineItem.isContainerStart() || inlineItem.isContainerEnd()) |
| return fontMetrics.height() + boxGeometry.verticalBorder() + boxGeometry.verticalPadding().valueOr(0); |
| |
| // Non-replaced inline box (e.g. inline-block) |
| return boxGeometry.borderBoxHeight(); |
| } |
| |
| LineBox::Baseline Line::halfLeadingMetrics(const FontMetrics& fontMetrics, LayoutUnit lineLogicalHeight) |
| { |
| auto ascent = fontMetrics.ascent(); |
| auto descent = fontMetrics.descent(); |
| // 10.8.1 Leading and half-leading |
| auto leading = lineLogicalHeight - (ascent + descent); |
| // Inline tree is all integer based. |
| auto adjustedAscent = std::max((ascent + leading / 2).floor(), 0); |
| auto adjustedDescent = std::max((descent + leading / 2).ceil(), 0); |
| return { adjustedAscent, adjustedDescent }; |
| } |
| |
| LayoutState& Line::layoutState() const |
| { |
| return formattingContext().layoutState(); |
| } |
| |
| const InlineFormattingContext& Line::formattingContext() const |
| { |
| return m_inlineFormattingContext; |
| } |
| |
| } |
| } |
| |
| #endif |
