| /* |
| * 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 "InlineLineBuilder.h" |
| |
| #if ENABLE(LAYOUT_FORMATTING_CONTEXT) |
| |
| #include "InlineFormattingContext.h" |
| #include "InlineSoftLineBreakItem.h" |
| #include "TextUtil.h" |
| #include <wtf/IsoMallocInlines.h> |
| |
| namespace WebCore { |
| namespace Layout { |
| |
| struct LineBuilder::ContinousContent { |
| public: |
| ContinousContent(const InlineItemRun&, bool textIsAlignJustify); |
| |
| bool append(const InlineItemRun&); |
| LineBuilder::Run close(); |
| |
| private: |
| static bool canBeExpanded(const InlineItemRun& run) { return run.isText() && !run.isCollapsed() && !run.isCollapsedToZeroAdvanceWidth(); } |
| bool canBeMerged(const InlineItemRun& run) const { return run.isText() && !run.isCollapsedToZeroAdvanceWidth() && &m_initialInlineRun.layoutBox() == &run.layoutBox(); } |
| |
| const InlineItemRun& m_initialInlineRun; |
| const bool m_textIsAlignJustify { false }; |
| unsigned m_expandedLength { 0 }; |
| LayoutUnit m_expandedWidth; |
| bool m_trailingRunCanBeExpanded { false }; |
| bool m_hasTrailingExpansionOpportunity { false }; |
| unsigned m_expansionOpportunityCount { 0 }; |
| }; |
| |
| LineBuilder::ContinousContent::ContinousContent(const InlineItemRun& initialInlineRun, bool textIsAlignJustify) |
| : m_initialInlineRun(initialInlineRun) |
| , m_textIsAlignJustify(textIsAlignJustify) |
| , m_trailingRunCanBeExpanded(canBeExpanded(initialInlineRun)) |
| { |
| } |
| |
| bool LineBuilder::ContinousContent::append(const InlineItemRun& inlineItemRun) |
| { |
| // Merged content needs to be continuous. |
| if (!m_trailingRunCanBeExpanded) |
| return false; |
| if (!canBeMerged(inlineItemRun)) |
| return false; |
| |
| m_trailingRunCanBeExpanded = canBeExpanded(inlineItemRun); |
| |
| ASSERT(inlineItemRun.isText()); |
| m_expandedLength += inlineItemRun.textContext()->length(); |
| m_expandedWidth += inlineItemRun.logicalWidth(); |
| |
| if (m_textIsAlignJustify) { |
| m_hasTrailingExpansionOpportunity = inlineItemRun.hasExpansionOpportunity(); |
| if (m_hasTrailingExpansionOpportunity) |
| ++m_expansionOpportunityCount; |
| } |
| return true; |
| } |
| |
| LineBuilder::Run LineBuilder::ContinousContent::close() |
| { |
| if (!m_expandedLength) |
| return { m_initialInlineRun }; |
| // Expand the text content and set the expansion opportunities. |
| ASSERT(m_initialInlineRun.isText()); |
| auto textContext = *m_initialInlineRun.textContext(); |
| auto length = textContext.length() + m_expandedLength; |
| textContext.expand(length); |
| |
| if (m_textIsAlignJustify) { |
| // FIXME: This is a very simple expansion merge. We should eventually switch over to FontCascade::expansionOpportunityCount. |
| ExpansionBehavior expansionBehavior = m_hasTrailingExpansionOpportunity ? (ForbidLeadingExpansion | AllowTrailingExpansion) : (AllowLeadingExpansion | AllowTrailingExpansion); |
| if (m_initialInlineRun.hasExpansionOpportunity()) |
| ++m_expansionOpportunityCount; |
| textContext.setExpansion({ expansionBehavior, { } }); |
| } |
| return { m_initialInlineRun, Display::Rect { 0_lu, m_initialInlineRun.logicalLeft(), m_initialInlineRun.logicalWidth() + m_expandedWidth, 0_lu }, textContext, m_expansionOpportunityCount }; |
| } |
| |
| LineBuilder::Run::Run(const InlineItemRun& inlineItemRun) |
| : m_layoutBox(&inlineItemRun.layoutBox()) |
| , m_type(inlineItemRun.type()) |
| , m_logicalRect({ 0_lu, inlineItemRun.logicalLeft(), inlineItemRun.logicalWidth(), 0_lu }) |
| , m_textContext(inlineItemRun.textContext()) |
| , m_isCollapsedToVisuallyEmpty(inlineItemRun.isCollapsedToZeroAdvanceWidth()) |
| { |
| if (inlineItemRun.hasExpansionOpportunity()) { |
| m_expansionOpportunityCount = 1; |
| ASSERT(m_textContext); |
| m_textContext->setExpansion({ DefaultExpansion, { } }); |
| } |
| } |
| |
| LineBuilder::Run::Run(const InlineItemRun& inlineItemRun, const Display::Rect& logicalRect, const Display::Run::TextContext& textContext, unsigned expansionOpportunityCount) |
| : m_layoutBox(&inlineItemRun.layoutBox()) |
| , m_type(inlineItemRun.type()) |
| , m_logicalRect(logicalRect) |
| , m_textContext(textContext) |
| , m_expansionOpportunityCount(expansionOpportunityCount) |
| , m_isCollapsedToVisuallyEmpty(inlineItemRun.isCollapsedToZeroAdvanceWidth()) |
| { |
| } |
| |
| void LineBuilder::Run::adjustExpansionBehavior(ExpansionBehavior expansionBehavior) |
| { |
| ASSERT(isText()); |
| ASSERT(hasExpansionOpportunity()); |
| m_textContext->setExpansion({ expansionBehavior, m_textContext->expansion()->horizontalExpansion }); |
| } |
| |
| inline Optional<ExpansionBehavior> LineBuilder::Run::expansionBehavior() const |
| { |
| ASSERT(isText()); |
| if (auto expansionContext = m_textContext->expansion()) |
| return expansionContext->behavior; |
| return { }; |
| } |
| |
| void LineBuilder::Run::setComputedHorizontalExpansion(LayoutUnit logicalExpansion) |
| { |
| ASSERT(isText()); |
| ASSERT(hasExpansionOpportunity()); |
| m_logicalRect.expandHorizontally(logicalExpansion); |
| m_textContext->setExpansion({ m_textContext->expansion()->behavior, logicalExpansion }); |
| } |
| |
| LineBuilder::LineBuilder(const InlineFormattingContext& inlineFormattingContext, Optional<TextAlignMode> horizontalAlignment, SkipAlignment skipAlignment) |
| : m_inlineFormattingContext(inlineFormattingContext) |
| , m_trimmableContent(m_inlineItemRuns) |
| , m_horizontalAlignment(horizontalAlignment) |
| , m_skipAlignment(skipAlignment == SkipAlignment::Yes) |
| { |
| } |
| |
| LineBuilder::~LineBuilder() |
| { |
| } |
| |
| void LineBuilder::initialize(const Constraints& constraints) |
| { |
| ASSERT(m_skipAlignment || constraints.heightAndBaseline); |
| |
| LayoutUnit initialLineHeight; |
| LayoutUnit initialBaselineOffset; |
| if (constraints.heightAndBaseline) { |
| m_initialStrut = constraints.heightAndBaseline->strut; |
| initialLineHeight = constraints.heightAndBaseline->height; |
| initialBaselineOffset = constraints.heightAndBaseline->baselineOffset; |
| } else |
| m_initialStrut = { }; |
| |
| auto lineRect = Display::Rect { constraints.logicalTopLeft, 0_lu, initialLineHeight }; |
| auto baseline = LineBox::Baseline { initialBaselineOffset, initialLineHeight - initialBaselineOffset }; |
| m_lineBox = LineBox { lineRect, baseline, initialBaselineOffset }; |
| m_lineLogicalWidth = constraints.availableLogicalWidth; |
| m_hasIntrusiveFloat = constraints.lineIsConstrainedByFloat; |
| |
| m_inlineItemRuns.clear(); |
| m_trimmableContent.reset(); |
| m_lineIsVisuallyEmptyBeforeTrimmableContent = { }; |
| } |
| |
| static bool shouldPreserveLeadingContent(const InlineTextItem& inlineTextItem) |
| { |
| if (!inlineTextItem.isWhitespace()) |
| return true; |
| auto whitespace = inlineTextItem.style().whiteSpace(); |
| return whitespace == WhiteSpace::Pre || whitespace == WhiteSpace::PreWrap || whitespace == WhiteSpace::BreakSpaces; |
| } |
| |
| LineBuilder::RunList LineBuilder::close(IsLastLineWithInlineContent isLastLineWithInlineContent) |
| { |
| // 1. Remove trimmable trailing content. |
| // 2. Join text runs together when possible [foo][ ][bar] -> [foo bar]. |
| // 3. Align merged runs both vertically and horizontally. |
| removeTrailingTrimmableContent(); |
| RunList runList; |
| unsigned runIndex = 0; |
| while (runIndex < m_inlineItemRuns.size()) { |
| // Merge eligible runs. |
| auto continousContent = ContinousContent { m_inlineItemRuns[runIndex], isTextAlignJustify() }; |
| while (++runIndex < m_inlineItemRuns.size()) { |
| if (!continousContent.append(m_inlineItemRuns[runIndex])) |
| break; |
| } |
| runList.append(continousContent.close()); |
| } |
| |
| if (!m_skipAlignment) { |
| for (auto& run : runList) { |
| adjustBaselineAndLineHeight(run); |
| run.setLogicalHeight(runContentHeight(run)); |
| } |
| if (isVisuallyEmpty()) { |
| m_lineBox.resetBaseline(); |
| m_lineBox.setLogicalHeight(0_lu); |
| } |
| // Remove descent when all content is baseline aligned but none of them have descent. |
| if (formattingContext().quirks().lineDescentNeedsCollapsing(runList)) { |
| m_lineBox.shrinkVertically(m_lineBox.baseline().descent()); |
| m_lineBox.resetDescent(); |
| } |
| alignContentVertically(runList); |
| alignContentHorizontally(runList, isLastLineWithInlineContent); |
| } |
| return runList; |
| } |
| |
| void LineBuilder::alignContentVertically(RunList& runList) |
| { |
| ASSERT(!m_skipAlignment); |
| for (auto& run : 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. |
| auto inlineBlockBaselineOffset = formattingState.displayInlineContent()->lineBoxes.last().baselineOffset(); |
| // The inline-block's baseline offset is relative to its content box. Let's convert it relative to the margin box. |
| // _______________ <- margin box |
| // | |
| // | ____________ <- border box |
| // | | |
| // | | _________ <- content box |
| // | | | ^ |
| // | | | | <- baseline offset |
| // | | | | |
| // text | | | v text |
| // -----|-|-|---------- <- baseline |
| // |
| auto& boxGeometry = formattingContext().geometryForBox(layoutBox); |
| auto baselineOffsetFromMarginBox = boxGeometry.marginBefore() + boxGeometry.borderTop() + boxGeometry.paddingTop().valueOr(0) + inlineBlockBaselineOffset; |
| logicalTop = baselineOffset() - baselineOffsetFromMarginBox; |
| } else |
| logicalTop = baselineOffset() - run.logicalRect().height(); |
| break; |
| case VerticalAlign::Top: |
| logicalTop = 0_lu; |
| 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 LineBuilder::justifyRuns(RunList& runList) const |
| { |
| ASSERT(!runList.isEmpty()); |
| ASSERT(availableWidth() > 0); |
| // Need to fix up the last run first. |
| auto& lastRun = runList.last(); |
| if (lastRun.hasExpansionOpportunity()) |
| lastRun.adjustExpansionBehavior(*lastRun.expansionBehavior() | ForbidTrailingExpansion); |
| // Collect the expansion opportunity numbers. |
| auto expansionOpportunityCount = 0; |
| for (auto& run : runList) |
| expansionOpportunityCount += run.expansionOpportunityCount(); |
| // Nothing to distribute? |
| if (!expansionOpportunityCount) |
| return; |
| // Distribute the extra space. |
| auto expansionToDistribute = availableWidth() / expansionOpportunityCount; |
| LayoutUnit accumulatedExpansion; |
| for (auto& run : runList) { |
| // Expand and moves runs by the accumulated expansion. |
| if (!run.hasExpansionOpportunity()) { |
| run.moveHorizontally(accumulatedExpansion); |
| continue; |
| } |
| ASSERT(run.expansionOpportunityCount()); |
| auto computedExpansion = expansionToDistribute * run.expansionOpportunityCount(); |
| run.setComputedHorizontalExpansion(computedExpansion); |
| run.moveHorizontally(accumulatedExpansion); |
| accumulatedExpansion += computedExpansion; |
| } |
| } |
| |
| void LineBuilder::alignContentHorizontally(RunList& runList, IsLastLineWithInlineContent lastLine) const |
| { |
| ASSERT(!m_skipAlignment); |
| if (runList.isEmpty() || availableWidth() <= 0) |
| return; |
| |
| if (isTextAlignJustify()) { |
| // Do not justify align the last line. |
| if (lastLine == IsLastLineWithInlineContent::No) |
| justifyRuns(runList); |
| return; |
| } |
| |
| 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 : runList) |
| run.moveHorizontally(*adjustment); |
| } |
| |
| void LineBuilder::removeTrailingTrimmableContent() |
| { |
| if (m_trimmableContent.isEmpty() || m_inlineItemRuns.isEmpty()) |
| return; |
| |
| m_lineBox.shrinkHorizontally(m_trimmableContent.trim()); |
| // If we trimmed the first visible run on the line, we need to re-check the visibility status. |
| if (!m_lineIsVisuallyEmptyBeforeTrimmableContent) |
| return; |
| // Just because the line was visually empty before the trimmed content, it does not necessarily mean it is still visually empty. |
| // <span> </span><span style="padding-left: 10px"></span> <- non-empty |
| auto lineIsVisuallyEmpty = [&] { |
| for (auto& run : m_inlineItemRuns) { |
| if (isVisuallyNonEmpty(run)) |
| return false; |
| } |
| return true; |
| }; |
| // We could only go from visually non empty -> to visually empty. Trimming runs should never make the line visible. |
| if (lineIsVisuallyEmpty()) |
| m_lineBox.setIsConsideredEmpty(); |
| m_lineIsVisuallyEmptyBeforeTrimmableContent = { }; |
| } |
| |
| void LineBuilder::moveLogicalLeft(LayoutUnit delta) |
| { |
| if (!delta) |
| return; |
| ASSERT(delta > 0); |
| m_lineBox.moveHorizontally(delta); |
| m_lineLogicalWidth -= delta; |
| } |
| |
| void LineBuilder::moveLogicalRight(LayoutUnit delta) |
| { |
| ASSERT(delta > 0); |
| m_lineLogicalWidth -= delta; |
| } |
| |
| void LineBuilder::append(const InlineItem& inlineItem, LayoutUnit logicalWidth) |
| { |
| if (inlineItem.isText()) |
| appendTextContent(downcast<InlineTextItem>(inlineItem), logicalWidth); |
| else if (inlineItem.isLineBreak()) |
| appendLineBreak(inlineItem); |
| else if (inlineItem.isContainerStart()) |
| appendInlineContainerStart(inlineItem, logicalWidth); |
| else if (inlineItem.isContainerEnd()) |
| appendInlineContainerEnd(inlineItem, logicalWidth); |
| else if (inlineItem.layoutBox().replaced()) |
| appendReplacedInlineBox(inlineItem, logicalWidth); |
| else if (inlineItem.isBox()) |
| appendNonReplacedInlineBox(inlineItem, logicalWidth); |
| else |
| ASSERT_NOT_REACHED(); |
| |
| // Check if this freshly appended content makes the line visually non-empty. |
| ASSERT(!m_inlineItemRuns.isEmpty()); |
| if (m_lineBox.isConsideredEmpty() && isVisuallyNonEmpty(m_inlineItemRuns.last())) |
| m_lineBox.setIsConsideredNonEmpty(); |
| } |
| |
| void LineBuilder::appendNonBreakableSpace(const InlineItem& inlineItem, LayoutUnit logicalLeft, LayoutUnit logicalWidth) |
| { |
| m_inlineItemRuns.append({ inlineItem, logicalLeft, logicalWidth }); |
| m_lineBox.expandHorizontally(logicalWidth); |
| } |
| |
| void LineBuilder::appendInlineContainerStart(const InlineItem& inlineItem, LayoutUnit logicalWidth) |
| { |
| // This is really just a placeholder to mark the start of the inline level container <span>. |
| appendNonBreakableSpace(inlineItem, contentLogicalWidth(), logicalWidth); |
| } |
| |
| void LineBuilder::appendInlineContainerEnd(const InlineItem& inlineItem, LayoutUnit logicalWidth) |
| { |
| // This is really just a placeholder to mark the end of the inline level container </span>. |
| auto trimTrailingLetterSpacing = [&] { |
| if (!m_trimmableContent.isTrailingRunPartiallyTrimmable()) |
| return; |
| m_lineBox.shrinkHorizontally(m_trimmableContent.trimTrailingRun()); |
| }; |
| // Prevent trailing letter-spacing from spilling out of the inline container. |
| // https://drafts.csswg.org/css-text-3/#letter-spacing-property See example 21. |
| trimTrailingLetterSpacing(); |
| appendNonBreakableSpace(inlineItem, contentLogicalRight(), logicalWidth); |
| } |
| |
| void LineBuilder::appendTextContent(const InlineTextItem& inlineItem, LayoutUnit logicalWidth) |
| { |
| auto willCollapseCompletely = [&] { |
| // Empty run. |
| if (!inlineItem.length()) { |
| ASSERT(!logicalWidth); |
| return true; |
| } |
| // Leading whitespace. |
| if (m_inlineItemRuns.isEmpty()) |
| return !shouldPreserveLeadingContent(inlineItem); |
| |
| if (!inlineItem.isCollapsible()) |
| return false; |
| // Check if the last item is collapsed as well. |
| for (auto i = m_inlineItemRuns.size(); i--;) { |
| auto& run = m_inlineItemRuns[i]; |
| if (run.isBox()) |
| return false; |
| // https://drafts.csswg.org/css-text-3/#white-space-phase-1 |
| // Any collapsible space immediately following another collapsible space—even one outside the boundary of the inline containing that space, |
| // provided both spaces are within the same inline formatting context—is collapsed to have zero advance width. |
| // : "<span> </span> " <- the trailing whitespace collapses completely. |
| // Not that when the inline container has preserve whitespace style, "<span style="white-space: pre"> </span> " <- this whitespace stays around. |
| if (run.isText()) |
| return run.isCollapsible(); |
| ASSERT(run.isContainerStart() || run.isContainerEnd()); |
| } |
| return true; |
| }; |
| |
| auto collapsesToZeroAdvanceWidth = willCollapseCompletely(); |
| auto collapsedRun = inlineItem.isCollapsible() && inlineItem.length() > 1; |
| auto contentStart = inlineItem.start(); |
| auto contentLength = collapsedRun ? 1 : inlineItem.length(); |
| m_inlineItemRuns.append({ inlineItem, contentLogicalWidth(), logicalWidth, Display::Run::TextContext { contentStart, contentLength, inlineItem.layoutBox().textContext()->content } }); |
| auto& lineRun = m_inlineItemRuns.last(); |
| |
| if (collapsesToZeroAdvanceWidth) |
| lineRun.setCollapsesToZeroAdvanceWidth(); |
| |
| if (collapsedRun) |
| lineRun.setIsCollapsed(); |
| |
| m_lineBox.expandHorizontally(lineRun.logicalWidth()); |
| |
| // Existing trailing trimmable content can only be expanded if the current rus is fully trimmable. |
| auto trimmableListNeedsReset = !m_trimmableContent.isEmpty() && !lineRun.isTrimmableWhitespace(); |
| if (trimmableListNeedsReset) |
| m_trimmableContent.reset(); |
| auto isTrimmable = lineRun.isTrimmableWhitespace() || lineRun.hasTrailingLetterSpacing(); |
| if (isTrimmable) { |
| // If we ever trim this content, we need to know if the line visibility state needs to be recomputed. |
| if (m_trimmableContent.isEmpty()) |
| m_lineIsVisuallyEmptyBeforeTrimmableContent = isVisuallyEmpty(); |
| m_trimmableContent.append(m_inlineItemRuns.size() - 1); |
| } |
| } |
| |
| void LineBuilder::appendNonReplacedInlineBox(const InlineItem& inlineItem, LayoutUnit logicalWidth) |
| { |
| auto& layoutBox = inlineItem.layoutBox(); |
| auto& boxGeometry = formattingContext().geometryForBox(layoutBox); |
| auto horizontalMargin = boxGeometry.horizontalMargin(); |
| m_inlineItemRuns.append({ inlineItem, contentLogicalWidth() + horizontalMargin.start, logicalWidth }); |
| m_lineBox.expandHorizontally(logicalWidth + horizontalMargin.start + horizontalMargin.end); |
| m_trimmableContent.reset(); |
| } |
| |
| void LineBuilder::appendReplacedInlineBox(const InlineItem& inlineItem, LayoutUnit logicalWidth) |
| { |
| ASSERT(inlineItem.layoutBox().isReplaced()); |
| // FIXME: Surely replaced boxes behave differently. |
| appendNonReplacedInlineBox(inlineItem, logicalWidth); |
| } |
| |
| void LineBuilder::appendLineBreak(const InlineItem& inlineItem) |
| { |
| if (inlineItem.isHardLineBreak()) |
| return m_inlineItemRuns.append({ inlineItem, contentLogicalWidth(), 0_lu }); |
| // Soft line breaks (preserved new line characters) require inline text boxes for compatibility reasons. |
| ASSERT(inlineItem.isSoftLineBreak()); |
| auto& softLineBreakItem = downcast<InlineSoftLineBreakItem>(inlineItem); |
| m_inlineItemRuns.append({ softLineBreakItem, contentLogicalWidth(), 0_lu, Display::Run::TextContext { softLineBreakItem.position(), 1, softLineBreakItem.layoutBox().textContext()->content } }); |
| } |
| |
| void LineBuilder::adjustBaselineAndLineHeight(const Run& run) |
| { |
| auto& baseline = m_lineBox.baseline(); |
| if (run.isText() || run.isLineBreak()) { |
| // 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; |
| m_lineBox.setAscentIfGreater(m_initialStrut->ascent()); |
| m_lineBox.setDescentIfGreater(m_initialStrut->descent()); |
| m_lineBox.setLogicalHeightIfGreater(baseline.height()); |
| m_initialStrut = { }; |
| return; |
| } |
| |
| auto& layoutBox = run.layoutBox(); |
| auto& style = layoutBox.style(); |
| if (run.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(); |
| 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) |
| m_lineBox.setDescentIfGreater(halfLeading.descent()); |
| if (halfLeading.ascent() > 0) |
| m_lineBox.setAscentIfGreater(halfLeading.ascent()); |
| m_lineBox.setLogicalHeightIfGreater(baseline.height()); |
| } else |
| m_lineBox.setLogicalHeightIfGreater(fontMetrics.height()); |
| return; |
| } |
| |
| if (run.isContainerEnd()) { |
| // The line's baseline and height have already been adjusted at ContainerStart. |
| return; |
| } |
| |
| if (run.isBox()) { |
| auto& boxGeometry = formattingContext().geometryForBox(layoutBox); |
| auto marginBoxHeight = boxGeometry.marginBoxHeight(); |
| |
| switch (style.verticalAlign()) { |
| case VerticalAlign::Baseline: { |
| 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. |
| auto& lastLineBox = formattingState.displayInlineContent()->lineBoxes.last(); |
| auto inlineBlockBaseline = lastLineBox.baseline(); |
| auto beforeHeight = boxGeometry.marginBefore() + boxGeometry.borderTop() + boxGeometry.paddingTop().valueOr(0); |
| |
| m_lineBox.setAscentIfGreater(inlineBlockBaseline.ascent()); |
| m_lineBox.setDescentIfGreater(inlineBlockBaseline.descent()); |
| m_lineBox.setBaselineOffsetIfGreater(beforeHeight + lastLineBox.baselineOffset()); |
| m_lineBox.setLogicalHeightIfGreater(marginBoxHeight); |
| } else { |
| // Non inline-block boxes sit on the baseline (including their bottom margin). |
| m_lineBox.setAscentIfGreater(marginBoxHeight); |
| // Ignore negative descent (yes, negative descent is a thing). |
| m_lineBox.setLogicalHeightIfGreater(marginBoxHeight + std::max(0_lu, baseline.descent())); |
| } |
| break; |
| } |
| case VerticalAlign::Top: |
| // Top align content never changes the baseline, it only pushes the bottom of the line further down. |
| m_lineBox.setLogicalHeightIfGreater(marginBoxHeight); |
| break; |
| case VerticalAlign::Bottom: { |
| // Bottom aligned, tall content pushes the baseline further down from the line top. |
| auto lineLogicalHeight = m_lineBox.logicalHeight(); |
| if (marginBoxHeight > lineLogicalHeight) { |
| m_lineBox.setLogicalHeightIfGreater(marginBoxHeight); |
| m_lineBox.setBaselineOffsetIfGreater(m_lineBox.baselineOffset() + (marginBoxHeight - lineLogicalHeight)); |
| } |
| break; |
| } |
| default: |
| ASSERT_NOT_IMPLEMENTED_YET(); |
| break; |
| } |
| return; |
| } |
| ASSERT_NOT_REACHED(); |
| } |
| |
| LayoutUnit LineBuilder::runContentHeight(const Run& run) const |
| { |
| ASSERT(!m_skipAlignment); |
| auto& fontMetrics = run.style().fontMetrics(); |
| if (run.isText() || run.isLineBreak()) |
| return fontMetrics.height(); |
| |
| if (run.isContainerStart() || run.isContainerEnd()) |
| return fontMetrics.height(); |
| |
| auto& layoutBox = run.layoutBox(); |
| auto& boxGeometry = formattingContext().geometryForBox(layoutBox); |
| if (layoutBox.replaced() || layoutBox.isFloatingPositioned()) |
| return boxGeometry.contentBoxHeight(); |
| |
| // Non-replaced inline box (e.g. inline-block). It looks a bit misleading but their margin box is considered the content height here. |
| return boxGeometry.marginBoxHeight(); |
| } |
| |
| bool LineBuilder::isVisuallyNonEmpty(const InlineItemRun& run) const |
| { |
| if (run.isText()) |
| return !run.isCollapsedToZeroAdvanceWidth(); |
| |
| // Note that this does not check whether the inline container has content. It simply checks if the container itself is considered non-empty. |
| if (run.isContainerStart() || run.isContainerEnd()) { |
| if (!run.logicalWidth()) |
| return false; |
| // Margin does not make the container visually non-empty. Check if it has border or padding. |
| auto& boxGeometry = formattingContext().geometryForBox(run.layoutBox()); |
| if (run.isContainerStart()) |
| return boxGeometry.borderLeft() || (boxGeometry.paddingLeft() && boxGeometry.paddingLeft().value()); |
| return boxGeometry.borderRight() || (boxGeometry.paddingRight() && boxGeometry.paddingRight().value()); |
| } |
| |
| if (run.isLineBreak()) |
| return true; |
| |
| if (run.isBox()) { |
| if (!run.layoutBox().establishesFormattingContext()) |
| return true; |
| ASSERT(run.layoutBox().isInlineBlockBox()); |
| if (!run.logicalWidth()) |
| return false; |
| if (m_skipAlignment || formattingContext().geometryForBox(run.layoutBox()).height()) |
| return true; |
| return false; |
| } |
| |
| ASSERT_NOT_REACHED(); |
| return false; |
| } |
| |
| LineBox::Baseline LineBuilder::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& LineBuilder::layoutState() const |
| { |
| return formattingContext().layoutState(); |
| } |
| |
| const InlineFormattingContext& LineBuilder::formattingContext() const |
| { |
| return m_inlineFormattingContext; |
| } |
| |
| LineBuilder::TrimmableContent::TrimmableContent(InlineItemRunList& inlineItemRunList) |
| : m_inlineitemRunList(inlineItemRunList) |
| { |
| } |
| |
| void LineBuilder::TrimmableContent::append(size_t runIndex) |
| { |
| auto& trimmableRun = m_inlineitemRunList[runIndex]; |
| LayoutUnit trimmableWidth; |
| auto isFullyTrimmable = trimmableRun.isTrimmableWhitespace(); |
| if (isFullyTrimmable) |
| trimmableWidth = trimmableRun.logicalWidth(); |
| else { |
| ASSERT(trimmableRun.hasTrailingLetterSpacing()); |
| trimmableWidth = trimmableRun.trailingLetterSpacing(); |
| } |
| // word-spacing could very well be negative, but it does not mean that the line gains that much extra space when the content is trimmed. |
| trimmableWidth = std::max(0_lu, trimmableWidth); |
| |
| ASSERT(trimmableWidth >= 0); |
| m_width += trimmableWidth; |
| m_lastRunIsFullyTrimmable = isFullyTrimmable; |
| m_firstRunIndex = m_firstRunIndex.valueOr(runIndex); |
| } |
| |
| LayoutUnit LineBuilder::TrimmableContent::trim() |
| { |
| ASSERT(!isEmpty()); |
| #ifndef NDEBUG |
| auto hasSeenNonWhitespaceTextContent = false; |
| #endif |
| // Collapse trimmable trailing content and move all the other trailing runs. |
| // <span> </span><span></span> -> |
| // [whitespace][container end][container start][container end] |
| // Trim the whitespace run and move the trailing inline container runs to the left. |
| LayoutUnit accumulatedTrimmedWidth; |
| for (auto index = *m_firstRunIndex; index < m_inlineitemRunList.size(); ++index) { |
| auto& run = m_inlineitemRunList[index]; |
| run.moveHorizontally(-accumulatedTrimmedWidth); |
| if (!run.isText()) { |
| ASSERT(run.isContainerStart() || run.isContainerEnd() || run.isLineBreak()); |
| continue; |
| } |
| if (run.isWhitespace()) { |
| accumulatedTrimmedWidth += run.logicalWidth(); |
| run.setCollapsesToZeroAdvanceWidth(); |
| } else { |
| ASSERT(!hasSeenNonWhitespaceTextContent); |
| #ifndef NDEBUG |
| hasSeenNonWhitespaceTextContent = true; |
| #endif |
| // Must be a letter spacing trim. |
| ASSERT(run.hasTrailingLetterSpacing()); |
| accumulatedTrimmedWidth += run.trailingLetterSpacing(); |
| run.removeTrailingLetterSpacing(); |
| } |
| } |
| ASSERT(accumulatedTrimmedWidth == width()); |
| reset(); |
| return accumulatedTrimmedWidth; |
| } |
| |
| LayoutUnit LineBuilder::TrimmableContent::trimTrailingRun() |
| { |
| ASSERT(!isEmpty()); |
| // Find the last trimmable run (it is not necessarily the last run e.g [container start][whitespace][container end]) |
| for (auto index = m_inlineitemRunList.size(); index-- && *m_firstRunIndex >= index;) { |
| auto& run = m_inlineitemRunList[index]; |
| if (!run.isText()) { |
| ASSERT(run.isContainerStart() || run.isContainerEnd()); |
| continue; |
| } |
| LayoutUnit trimmedWidth; |
| if (run.isWhitespace()) { |
| trimmedWidth = run.logicalWidth(); |
| run.setCollapsesToZeroAdvanceWidth(); |
| } else { |
| ASSERT(run.hasTrailingLetterSpacing()); |
| trimmedWidth = run.trailingLetterSpacing(); |
| run.removeTrailingLetterSpacing(); |
| } |
| m_width -= trimmedWidth; |
| // We managed to trim the last trimmable run. |
| if (index == *m_firstRunIndex) { |
| ASSERT(!m_width); |
| m_firstRunIndex = { }; |
| } |
| return trimmedWidth; |
| } |
| ASSERT_NOT_REACHED(); |
| return 0_lu; |
| } |
| |
| LineBuilder::InlineItemRun::InlineItemRun(const InlineItem& inlineItem, LayoutUnit logicalLeft, LayoutUnit logicalWidth, WTF::Optional<Display::Run::TextContext> textContext) |
| : m_inlineItem(inlineItem) |
| , m_logicalLeft(logicalLeft) |
| , m_logicalWidth(logicalWidth) |
| , m_textContext(textContext) |
| { |
| } |
| |
| bool LineBuilder::InlineItemRun::isTrimmableWhitespace() const |
| { |
| if (!isWhitespace()) |
| return false; |
| return !TextUtil::shouldPreserveTrailingWhitespace(style()); |
| } |
| |
| bool LineBuilder::InlineItemRun::hasTrailingLetterSpacing() const |
| { |
| return !isWhitespace() && style().letterSpacing() > 0; |
| } |
| |
| LayoutUnit LineBuilder::InlineItemRun::trailingLetterSpacing() const |
| { |
| if (!hasTrailingLetterSpacing()) |
| return 0_lu; |
| return LayoutUnit { style().letterSpacing() }; |
| } |
| |
| void LineBuilder::InlineItemRun::setCollapsesToZeroAdvanceWidth() |
| { |
| m_collapsedToZeroAdvanceWidth = true; |
| m_logicalWidth = 0_lu; |
| } |
| |
| void LineBuilder::InlineItemRun::removeTrailingLetterSpacing() |
| { |
| ASSERT(hasTrailingLetterSpacing()); |
| m_logicalWidth -= trailingLetterSpacing(); |
| ASSERT(m_logicalWidth > 0 || (!m_logicalWidth && style().letterSpacing() >= intMaxForLayoutUnit)); |
| } |
| |
| } |
| } |
| |
| #endif |
