| /* |
| * 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 "RuntimeEnabledFeatures.h" |
| #include "TextUtil.h" |
| #include <wtf/IsoMallocInlines.h> |
| |
| namespace WebCore { |
| namespace Layout { |
| |
| static inline bool isWhitespacePreserved(const RenderStyle& style) |
| { |
| auto whitespace = style.whiteSpace(); |
| return whitespace == WhiteSpace::Pre || whitespace == WhiteSpace::PreWrap || whitespace == WhiteSpace::BreakSpaces; |
| } |
| |
| struct HangingContent { |
| public: |
| void reset(); |
| |
| InlineLayoutUnit width() const { return m_width; } |
| bool isConditional() const { return m_isConditional; } |
| |
| void setIsConditional() { m_isConditional = true; } |
| void expand(InlineLayoutUnit width) { m_width += width; } |
| |
| private: |
| bool m_isConditional { false }; |
| InlineLayoutUnit m_width { 0 }; |
| }; |
| |
| void HangingContent::reset() |
| { |
| m_isConditional = false; |
| m_width = 0; |
| } |
| |
| LineBuilder::LineBuilder(const InlineFormattingContext& inlineFormattingContext, Optional<TextAlignMode> horizontalAlignment, IntrinsicSizing intrinsicSizing) |
| : m_inlineFormattingContext(inlineFormattingContext) |
| , m_trimmableTrailingContent(m_runs) |
| , m_horizontalAlignment(horizontalAlignment) |
| , m_isIntrinsicSizing(intrinsicSizing == IntrinsicSizing::Yes) |
| , m_shouldIgnoreTrailingLetterSpacing(RuntimeEnabledFeatures::sharedFeatures().layoutFormattingContextIntegrationEnabled()) |
| { |
| } |
| |
| LineBuilder::~LineBuilder() |
| { |
| } |
| |
| void LineBuilder::initialize(const Constraints& constraints) |
| { |
| ASSERT(m_isIntrinsicSizing || constraints.heightAndBaseline); |
| |
| InlineLayoutUnit initialLineHeight = 0; |
| InlineLayoutUnit initialBaselineOffset = 0; |
| if (constraints.heightAndBaseline) { |
| m_initialStrut = constraints.heightAndBaseline->strut; |
| initialLineHeight = constraints.heightAndBaseline->height; |
| initialBaselineOffset = constraints.heightAndBaseline->baselineOffset; |
| } else |
| m_initialStrut = { }; |
| |
| auto lineRect = Display::InlineRect { constraints.logicalTopLeft, 0_lu, initialLineHeight }; |
| auto baseline = LineBoxBuilder::Baseline { initialBaselineOffset, initialLineHeight - initialBaselineOffset }; |
| m_lineBox = LineBoxBuilder { lineRect, baseline, initialBaselineOffset }; |
| m_lineLogicalWidth = constraints.availableLogicalWidth; |
| m_hasIntrusiveFloat = constraints.lineIsConstrainedByFloat; |
| |
| resetContent(); |
| } |
| |
| void LineBuilder::resetContent() |
| { |
| m_lineBox.setLogicalWidth({ }); |
| m_lineBox.setIsConsideredEmpty(); |
| m_runs.clear(); |
| m_trimmableTrailingContent.reset(); |
| m_lineIsVisuallyEmptyBeforeTrimmableTrailingContent = { }; |
| } |
| |
| 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(); |
| visuallyCollapsePreWrapOverflowContent(); |
| auto hangingContent = collectHangingContent(isLastLineWithInlineContent); |
| |
| if (!m_isIntrinsicSizing) { |
| for (auto& run : m_runs) { |
| adjustBaselineAndLineHeight(run); |
| run.setLogicalHeight(runContentHeight(run)); |
| } |
| if (isVisuallyEmpty()) { |
| m_lineBox.resetBaseline(); |
| m_lineBox.setLogicalHeight({ }); |
| } |
| // Remove descent when all content is baseline aligned but none of them have descent. |
| if (formattingContext().quirks().lineDescentNeedsCollapsing(m_runs)) { |
| m_lineBox.shrinkVertically(m_lineBox.baseline().descent()); |
| m_lineBox.resetDescent(); |
| } |
| alignContentVertically(); |
| alignHorizontally(hangingContent, isLastLineWithInlineContent); |
| } |
| return WTFMove(m_runs); |
| } |
| |
| void LineBuilder::alignContentVertically() |
| { |
| ASSERT(!m_isIntrinsicSizing); |
| auto scrollableOverflowRect = m_lineBox.logicalRect(); |
| for (auto& run : m_runs) { |
| InlineLayoutUnit logicalTop = 0; |
| 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 = layoutState().establishedInlineFormattingState(downcast<ContainerBox>(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); |
| // Adjust scrollable overflow if the run overflows the line. |
| scrollableOverflowRect.expandVerticallyToContain(run.logicalRect()); |
| // 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()); |
| } |
| m_lineBox.setScrollableOverflow(scrollableOverflowRect); |
| } |
| |
| void LineBuilder::justifyRuns(InlineLayoutUnit availableWidth) |
| { |
| ASSERT(availableWidth > 0); |
| // Collect the expansion opportunity numbers and find the last run with content. |
| auto expansionOpportunityCount = 0; |
| Run* lastRunWithContent = nullptr; |
| for (auto& run : m_runs) { |
| expansionOpportunityCount += run.expansionOpportunityCount(); |
| if (run.isText() || run.isBox()) |
| lastRunWithContent = &run; |
| } |
| // Need to fix up the last run's trailing expansion. |
| if (lastRunWithContent && lastRunWithContent->hasExpansionOpportunity()) { |
| // Turn off the trailing bits first and add the forbid trailing expansion. |
| auto leadingExpansion = lastRunWithContent->expansionBehavior() & LeadingExpansionMask; |
| lastRunWithContent->setExpansionBehavior(leadingExpansion | ForbidTrailingExpansion); |
| } |
| // Nothing to distribute? |
| if (!expansionOpportunityCount) |
| return; |
| // Distribute the extra space. |
| auto expansionToDistribute = availableWidth / expansionOpportunityCount; |
| InlineLayoutUnit accumulatedExpansion = 0; |
| for (auto& run : m_runs) { |
| // 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::alignHorizontally(const HangingContent& hangingContent, IsLastLineWithInlineContent isLastLine) |
| { |
| ASSERT(!m_isIntrinsicSizing); |
| |
| auto availableWidth = this->availableWidth() + hangingContent.width(); |
| if (m_runs.isEmpty() || availableWidth <= 0) |
| return; |
| |
| auto computedHorizontalAlignment = [&] { |
| ASSERT(m_horizontalAlignment); |
| if (m_horizontalAlignment != TextAlignMode::Justify) |
| return *m_horizontalAlignment; |
| // Text is justified according to the method specified by the text-justify property, |
| // in order to exactly fill the line box. Unless otherwise specified by text-align-last, |
| // the last line before a forced break or the end of the block is start-aligned. |
| if (m_runs.last().isLineBreak() || isLastLine == IsLastLineWithInlineContent::Yes) |
| return TextAlignMode::Start; |
| return TextAlignMode::Justify; |
| }(); |
| |
| if (computedHorizontalAlignment == TextAlignMode::Justify) { |
| justifyRuns(availableWidth); |
| return; |
| } |
| |
| auto adjustmentForAlignment = [] (auto horizontalAlignment, auto availableWidth) -> Optional<InlineLayoutUnit> { |
| switch (horizontalAlignment) { |
| case TextAlignMode::Left: |
| case TextAlignMode::WebKitLeft: |
| case TextAlignMode::Start: |
| return { }; |
| case TextAlignMode::Right: |
| case TextAlignMode::WebKitRight: |
| case TextAlignMode::End: |
| return std::max<InlineLayoutUnit>(availableWidth, 0); |
| case TextAlignMode::Center: |
| case TextAlignMode::WebKitCenter: |
| return std::max<InlineLayoutUnit>(availableWidth / 2, 0); |
| case TextAlignMode::Justify: |
| ASSERT_NOT_REACHED(); |
| break; |
| } |
| ASSERT_NOT_REACHED(); |
| return { }; |
| }; |
| |
| auto adjustment = adjustmentForAlignment(computedHorizontalAlignment, availableWidth); |
| if (!adjustment) |
| return; |
| // Horizontal alignment means that we not only adjust the runs but also make sure |
| // that the line box is aligned as well |
| // e.g. <div style="text-align: center; width: 100px;">centered text</div> : the line box will also be centered |
| // as opposed to start at 0px all the way to [centered text] run's right edge. |
| m_lineBox.moveHorizontally(*adjustment); |
| for (auto& run : m_runs) |
| run.moveHorizontally(*adjustment); |
| } |
| |
| void LineBuilder::removeTrailingTrimmableContent() |
| { |
| if (m_trimmableTrailingContent.isEmpty() || m_runs.isEmpty()) |
| return; |
| |
| // Complex line layout quirk: keep the trailing whitespace around when it is followed by a line break, unless the content overflows the line. |
| if (RuntimeEnabledFeatures::sharedFeatures().layoutFormattingContextIntegrationEnabled()) { |
| auto isTextAlignRight = [&] { |
| ASSERT(m_horizontalAlignment); |
| return m_horizontalAlignment == TextAlignMode::Right |
| || m_horizontalAlignment == TextAlignMode::WebKitRight |
| || m_horizontalAlignment == TextAlignMode::End; |
| }(); |
| |
| if (m_runs.last().isLineBreak() && availableWidth() >= 0 && !isTextAlignRight) { |
| m_trimmableTrailingContent.reset(); |
| return; |
| } |
| } |
| |
| m_lineBox.shrinkHorizontally(m_trimmableTrailingContent.remove()); |
| // If we removed the first visible run on the line, we need to re-check the visibility status. |
| if (m_lineIsVisuallyEmptyBeforeTrimmableTrailingContent) { |
| // Just because the line was visually empty before the removed 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_runs) { |
| if (isVisuallyNonEmpty(run)) |
| return false; |
| } |
| return true; |
| }; |
| // We could only go from visually non empty -> to visually empty. Trimmed runs should never make the line visible. |
| if (lineIsVisuallyEmpty()) |
| m_lineBox.setIsConsideredEmpty(); |
| m_lineIsVisuallyEmptyBeforeTrimmableTrailingContent = { }; |
| } |
| } |
| |
| void LineBuilder::visuallyCollapsePreWrapOverflowContent() |
| { |
| ASSERT(m_trimmableTrailingContent.isEmpty()); |
| // If white-space is set to pre-wrap, the UA must |
| // ... |
| // It may also visually collapse the character advance widths of any that would otherwise overflow. |
| auto overflowWidth = -availableWidth(); |
| if (overflowWidth <= 0) |
| return; |
| // Let's just find the trailing pre-wrap whitespace content for now (e.g check if there are multiple trailing runs with |
| // different set of white-space values and decide if the in-between pre-wrap content should be collapsed as well.) |
| InlineLayoutUnit trimmedContentWidth = 0; |
| for (auto& run : WTF::makeReversedRange(m_runs)) { |
| if (run.style().whiteSpace() != WhiteSpace::PreWrap) { |
| // We are only interested in pre-wrap trailing content. |
| break; |
| } |
| auto preWrapVisuallyCollapsibleInlineItem = run.isContainerStart() || run.isContainerEnd() || run.hasTrailingWhitespace(); |
| if (!preWrapVisuallyCollapsibleInlineItem) |
| break; |
| ASSERT(!run.hasCollapsibleTrailingWhitespace()); |
| InlineLayoutUnit trimmableWidth = { }; |
| if (run.isText()) { |
| // FIXME: We should always collapse the run at a glyph boundary as the spec indicates: "collapse the character advance widths of any that would otherwise overflow" |
| // and the trimmed width should be capped at std::min(run.trailingWhitespaceWidth(), overflowWidth) for texgt runs. Both FF and Chrome agree. |
| trimmableWidth = run.trailingWhitespaceWidth(); |
| run.visuallyCollapseTrailingWhitespace(); |
| } else { |
| trimmableWidth = run.logicalWidth(); |
| run.shrinkHorizontally(trimmableWidth); |
| } |
| trimmedContentWidth += trimmableWidth; |
| overflowWidth -= trimmableWidth; |
| if (overflowWidth <= 0) |
| break; |
| } |
| m_lineBox.shrinkHorizontally(trimmedContentWidth); |
| } |
| |
| HangingContent LineBuilder::collectHangingContent(IsLastLineWithInlineContent isLastLineWithInlineContent) |
| { |
| auto hangingContent = HangingContent { }; |
| // Can't setup hanging content with removable trailing whitespace. |
| ASSERT(m_trimmableTrailingContent.isEmpty()); |
| if (isLastLineWithInlineContent == IsLastLineWithInlineContent::Yes) |
| hangingContent.setIsConditional(); |
| for (auto& run : WTF::makeReversedRange(m_runs)) { |
| if (run.isContainerStart() || run.isContainerEnd()) |
| continue; |
| if (run.isLineBreak()) { |
| hangingContent.setIsConditional(); |
| continue; |
| } |
| if (!run.hasTrailingWhitespace()) |
| break; |
| // Check if we have a preserved or hung whitespace. |
| if (run.style().whiteSpace() != WhiteSpace::PreWrap) |
| break; |
| // This is either a normal or conditionally hanging trailing whitespace. |
| hangingContent.expand(run.trailingWhitespaceWidth()); |
| } |
| return hangingContent; |
| } |
| |
| void LineBuilder::moveLogicalLeft(InlineLayoutUnit delta) |
| { |
| if (!delta) |
| return; |
| ASSERT(delta > 0); |
| m_lineBox.moveHorizontally(delta); |
| m_lineLogicalWidth -= delta; |
| } |
| |
| void LineBuilder::moveLogicalRight(InlineLayoutUnit delta) |
| { |
| ASSERT(delta > 0); |
| m_lineLogicalWidth -= delta; |
| } |
| |
| void LineBuilder::append(const InlineItem& inlineItem, InlineLayoutUnit logicalWidth) |
| { |
| appendWith(inlineItem, { logicalWidth, false }); |
| } |
| |
| void LineBuilder::appendPartialTrailingTextItem(const InlineTextItem& inlineTextItem, InlineLayoutUnit logicalWidth, bool needsHyphen) |
| { |
| appendWith(inlineTextItem, { logicalWidth, needsHyphen }); |
| } |
| |
| void LineBuilder::appendWith(const InlineItem& inlineItem, const InlineRunDetails& inlineRunDetails) |
| { |
| if (inlineItem.isText()) |
| appendTextContent(downcast<InlineTextItem>(inlineItem), inlineRunDetails.logicalWidth, inlineRunDetails.needsHyphen); |
| else if (inlineItem.isLineBreak()) |
| appendLineBreak(inlineItem); |
| else if (inlineItem.isContainerStart()) |
| appendInlineContainerStart(inlineItem, inlineRunDetails.logicalWidth); |
| else if (inlineItem.isContainerEnd()) |
| appendInlineContainerEnd(inlineItem, inlineRunDetails.logicalWidth); |
| else if (inlineItem.layoutBox().isReplacedBox()) |
| appendReplacedInlineBox(inlineItem, inlineRunDetails.logicalWidth); |
| else if (inlineItem.isBox()) |
| appendNonReplacedInlineBox(inlineItem, inlineRunDetails.logicalWidth); |
| else |
| ASSERT_NOT_REACHED(); |
| |
| // Check if this freshly appended content makes the line visually non-empty. |
| if (m_lineBox.isConsideredEmpty() && !m_runs.isEmpty() && isVisuallyNonEmpty(m_runs.last())) |
| m_lineBox.setIsConsideredNonEmpty(); |
| } |
| |
| void LineBuilder::appendNonBreakableSpace(const InlineItem& inlineItem, InlineLayoutUnit logicalLeft, InlineLayoutUnit logicalWidth) |
| { |
| m_runs.append({ inlineItem, logicalLeft, logicalWidth }); |
| m_lineBox.expandHorizontally(logicalWidth); |
| } |
| |
| void LineBuilder::appendInlineContainerStart(const InlineItem& inlineItem, InlineLayoutUnit 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, InlineLayoutUnit logicalWidth) |
| { |
| // This is really just a placeholder to mark the end of the inline level container </span>. |
| auto removeTrailingLetterSpacing = [&] { |
| if (!m_trimmableTrailingContent.isTrailingRunPartiallyTrimmable()) |
| return; |
| m_lineBox.shrinkHorizontally(m_trimmableTrailingContent.removePartiallyTrimmableContent()); |
| }; |
| // Prevent trailing letter-spacing from spilling out of the inline container. |
| // https://drafts.csswg.org/css-text-3/#letter-spacing-property See example 21. |
| removeTrailingLetterSpacing(); |
| appendNonBreakableSpace(inlineItem, contentLogicalRight(), logicalWidth); |
| } |
| |
| void LineBuilder::appendTextContent(const InlineTextItem& inlineTextItem, InlineLayoutUnit logicalWidth, bool needsHyphen) |
| { |
| auto willCollapseCompletely = [&] { |
| if (!inlineTextItem.isCollapsible()) |
| return false; |
| if (inlineTextItem.isEmptyContent()) |
| return true; |
| // Check if the last item is collapsed as well. |
| for (auto& run : WTF::makeReversedRange(m_runs)) { |
| 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.hasCollapsibleTrailingWhitespace(); |
| ASSERT(run.isContainerStart() || run.isContainerEnd()); |
| } |
| // Leading whitespace. |
| return !isWhitespacePreserved(inlineTextItem.style()); |
| }; |
| |
| if (willCollapseCompletely()) |
| return; |
| |
| auto inlineTextItemNeedsNewRun = true; |
| if (!m_runs.isEmpty()) { |
| auto& lastRun = m_runs.last(); |
| inlineTextItemNeedsNewRun = lastRun.hasCollapsedTrailingWhitespace() || !lastRun.isText() || &lastRun.layoutBox() != &inlineTextItem.layoutBox(); |
| if (!inlineTextItemNeedsNewRun) { |
| lastRun.expand(inlineTextItem, logicalWidth); |
| if (needsHyphen) { |
| ASSERT(!lastRun.textContent()->needsHyphen()); |
| lastRun.setNeedsHyphen(); |
| } |
| } |
| } |
| if (inlineTextItemNeedsNewRun) |
| m_runs.append({ inlineTextItem, contentLogicalWidth(), logicalWidth, needsHyphen }); |
| |
| m_lineBox.expandHorizontally(logicalWidth); |
| |
| // Set the trailing trimmable content. |
| if (inlineTextItem.isWhitespace() && !TextUtil::shouldPreserveTrailingWhitespace(inlineTextItem.style())) { |
| m_trimmableTrailingContent.addFullyTrimmableContent(m_runs.size() - 1, logicalWidth); |
| // If we ever trim this content, we need to know if the line visibility state needs to be recomputed. |
| if (m_trimmableTrailingContent.isEmpty()) |
| m_lineIsVisuallyEmptyBeforeTrimmableTrailingContent = isVisuallyEmpty(); |
| return; |
| } |
| // Any non-whitespace, no-trimmable content resets the existing trimmable. |
| m_trimmableTrailingContent.reset(); |
| if (!m_shouldIgnoreTrailingLetterSpacing && !inlineTextItem.isWhitespace() && inlineTextItem.style().letterSpacing() > 0) |
| m_trimmableTrailingContent.addPartiallyTrimmableContent(m_runs.size() - 1, logicalWidth); |
| } |
| |
| void LineBuilder::appendNonReplacedInlineBox(const InlineItem& inlineItem, InlineLayoutUnit logicalWidth) |
| { |
| auto& layoutBox = inlineItem.layoutBox(); |
| auto& boxGeometry = formattingContext().geometryForBox(layoutBox); |
| auto horizontalMargin = boxGeometry.horizontalMargin(); |
| m_runs.append({ inlineItem, contentLogicalWidth() + horizontalMargin.start, logicalWidth }); |
| m_lineBox.expandHorizontally(logicalWidth + horizontalMargin.start + horizontalMargin.end); |
| m_trimmableTrailingContent.reset(); |
| } |
| |
| void LineBuilder::appendReplacedInlineBox(const InlineItem& inlineItem, InlineLayoutUnit logicalWidth) |
| { |
| ASSERT(inlineItem.layoutBox().isReplacedBox()); |
| // FIXME: Surely replaced boxes behave differently. |
| appendNonReplacedInlineBox(inlineItem, logicalWidth); |
| } |
| |
| void LineBuilder::appendLineBreak(const InlineItem& inlineItem) |
| { |
| if (inlineItem.isHardLineBreak()) |
| return m_runs.append({ inlineItem, contentLogicalWidth(), 0_lu }); |
| // Soft line breaks (preserved new line characters) require inline text boxes for compatibility reasons. |
| ASSERT(inlineItem.isSoftLineBreak()); |
| m_runs.append({ downcast<InlineSoftLineBreakItem>(inlineItem), contentLogicalWidth() }); |
| } |
| |
| 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 = layoutState().establishedInlineFormattingState(downcast<ContainerBox>(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<InlineLayoutUnit>(0, 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(); |
| } |
| |
| InlineLayoutUnit LineBuilder::runContentHeight(const Run& run) const |
| { |
| ASSERT(!m_isIntrinsicSizing); |
| 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.isReplacedBox() || 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 Run& run) const |
| { |
| if (run.isText()) |
| return true; |
| |
| if (run.isLineBreak()) |
| return true; |
| |
| // 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.isBox()) { |
| if (run.layoutBox().isReplacedBox()) |
| return true; |
| ASSERT(run.layoutBox().isInlineBlockBox() || run.layoutBox().isInlineTableBox()); |
| if (!run.logicalWidth()) |
| return false; |
| if (m_isIntrinsicSizing || formattingContext().geometryForBox(run.layoutBox()).height()) |
| return true; |
| return false; |
| } |
| |
| ASSERT_NOT_REACHED(); |
| return false; |
| } |
| |
| LineBoxBuilder::Baseline LineBuilder::halfLeadingMetrics(const FontMetrics& fontMetrics, InlineLayoutUnit lineLogicalHeight) |
| { |
| auto ascent = fontMetrics.ascent(); |
| auto descent = fontMetrics.descent(); |
| // 10.8.1 Leading and half-leading |
| auto halfLeading = (lineLogicalHeight - (ascent + descent)) / 2; |
| // Inline tree height is all integer based. |
| auto adjustedAscent = std::max<InlineLayoutUnit>(floorf(ascent + halfLeading), 0); |
| auto adjustedDescent = std::max<InlineLayoutUnit>(ceilf(descent + halfLeading), 0); |
| return { adjustedAscent, adjustedDescent }; |
| } |
| |
| LayoutState& LineBuilder::layoutState() const |
| { |
| return formattingContext().layoutState(); |
| } |
| |
| const InlineFormattingContext& LineBuilder::formattingContext() const |
| { |
| return m_inlineFormattingContext; |
| } |
| |
| LineBuilder::TrimmableTrailingContent::TrimmableTrailingContent(RunList& runs) |
| : m_runs(runs) |
| { |
| } |
| |
| void LineBuilder::TrimmableTrailingContent::addFullyTrimmableContent(size_t runIndex, InlineLayoutUnit trimmableWidth) |
| { |
| // Any subsequent trimmable whitespace should collapse to zero advanced width and ignored at ::appendTextContent(). |
| ASSERT(!m_hasFullyTrimmableContent); |
| m_fullyTrimmableWidth = trimmableWidth; |
| // Note that just becasue the trimmable width is 0 (font-size: 0px), it does not mean we don't have a trimmable trailing content. |
| m_hasFullyTrimmableContent = true; |
| m_firstRunIndex = m_firstRunIndex.valueOr(runIndex); |
| } |
| |
| void LineBuilder::TrimmableTrailingContent::addPartiallyTrimmableContent(size_t runIndex, InlineLayoutUnit trimmableWidth) |
| { |
| // Do not add trimmable letter spacing after a fully trimmable whitesapce. |
| ASSERT(!m_firstRunIndex); |
| ASSERT(!m_hasFullyTrimmableContent); |
| ASSERT(!m_partiallyTrimmableWidth); |
| ASSERT(trimmableWidth); |
| m_partiallyTrimmableWidth = trimmableWidth; |
| m_firstRunIndex = runIndex; |
| } |
| |
| InlineLayoutUnit LineBuilder::TrimmableTrailingContent::remove() |
| { |
| // Remove trimmable trailing content and move all the subsequent trailing runs. |
| // <span> </span><span></span> |
| // [trailing whitespace][container end][container start][container end] |
| // Trim the whitespace run and move the trailing inline container runs to the logical left. |
| ASSERT(!isEmpty()); |
| auto& trimmableRun = m_runs[*m_firstRunIndex]; |
| ASSERT(trimmableRun.isText()); |
| |
| if (m_hasFullyTrimmableContent) |
| trimmableRun.removeTrailingWhitespace(); |
| if (m_partiallyTrimmableWidth) |
| trimmableRun.removeTrailingLetterSpacing(); |
| |
| auto trimmableWidth = width(); |
| for (auto index = *m_firstRunIndex + 1; index < m_runs.size(); ++index) { |
| auto& run = m_runs[index]; |
| ASSERT(run.isContainerStart() || run.isContainerEnd() || run.isLineBreak()); |
| run.moveHorizontally(-trimmableWidth); |
| } |
| reset(); |
| return trimmableWidth; |
| } |
| |
| InlineLayoutUnit LineBuilder::TrimmableTrailingContent::removePartiallyTrimmableContent() |
| { |
| // Partially trimmable content is always gated by a fully trimmable content. |
| // We can't just trim spacing in the middle. |
| ASSERT(!m_fullyTrimmableWidth); |
| return remove(); |
| } |
| |
| LineBuilder::Run::Run(const InlineItem& inlineItem, InlineLayoutUnit logicalLeft, InlineLayoutUnit logicalWidth) |
| : m_type(inlineItem.type()) |
| , m_layoutBox(&inlineItem.layoutBox()) |
| , m_logicalRect({ 0, logicalLeft, logicalWidth, 0 }) |
| { |
| } |
| |
| LineBuilder::Run::Run(const InlineSoftLineBreakItem& softLineBreakItem, InlineLayoutUnit logicalLeft) |
| : m_type(softLineBreakItem.type()) |
| , m_layoutBox(&softLineBreakItem.layoutBox()) |
| , m_logicalRect({ 0, logicalLeft, 0, 0 }) |
| , m_textContent({ softLineBreakItem.position(), 1, softLineBreakItem.inlineTextBox().content(), false }) |
| { |
| } |
| |
| LineBuilder::Run::Run(const InlineTextItem& inlineTextItem, InlineLayoutUnit logicalLeft, InlineLayoutUnit logicalWidth, bool needsHyphen) |
| : m_type(InlineItem::Type::Text) |
| , m_layoutBox(&inlineTextItem.layoutBox()) |
| , m_logicalRect({ 0, logicalLeft, logicalWidth, 0 }) |
| , m_trailingWhitespaceType(trailingWhitespaceType(inlineTextItem)) |
| , m_textContent({ inlineTextItem.start(), m_trailingWhitespaceType == TrailingWhitespace::Collapsed ? 1 : inlineTextItem.length(), inlineTextItem.inlineTextBox().content(), needsHyphen }) |
| { |
| if (m_trailingWhitespaceType != TrailingWhitespace::None) { |
| m_trailingWhitespaceWidth = logicalWidth; |
| if (!isWhitespacePreserved(inlineTextItem.style())) |
| m_expansionOpportunityCount = 1; |
| } |
| } |
| |
| void LineBuilder::Run::expand(const InlineTextItem& inlineTextItem, InlineLayoutUnit logicalWidth) |
| { |
| // FIXME: This is a very simple expansion merge. We should eventually switch over to FontCascade::expansionOpportunityCount. |
| ASSERT(!hasCollapsedTrailingWhitespace()); |
| ASSERT(isText() && inlineTextItem.isText()); |
| ASSERT(m_layoutBox == &inlineTextItem.layoutBox()); |
| |
| m_logicalRect.expandHorizontally(logicalWidth); |
| m_trailingWhitespaceType = trailingWhitespaceType(inlineTextItem); |
| |
| if (m_trailingWhitespaceType == TrailingWhitespace::None) { |
| m_trailingWhitespaceWidth = { }; |
| setExpansionBehavior(AllowLeadingExpansion | AllowTrailingExpansion); |
| m_textContent->expand(inlineTextItem.length()); |
| return; |
| } |
| m_trailingWhitespaceWidth += logicalWidth; |
| if (!isWhitespacePreserved(inlineTextItem.style())) |
| ++m_expansionOpportunityCount; |
| setExpansionBehavior(DefaultExpansion); |
| m_textContent->expand(m_trailingWhitespaceType == TrailingWhitespace::Collapsed ? 1 : inlineTextItem.length()); |
| } |
| |
| bool LineBuilder::Run::hasTrailingLetterSpacing() const |
| { |
| // Complex line layout does not keep track of trailing letter spacing. |
| if (RuntimeEnabledFeatures::sharedFeatures().layoutFormattingContextIntegrationEnabled()) |
| return false; |
| return !hasTrailingWhitespace() && style().letterSpacing() > 0; |
| } |
| |
| InlineLayoutUnit LineBuilder::Run::trailingLetterSpacing() const |
| { |
| if (!hasTrailingLetterSpacing()) |
| return 0_lu; |
| return InlineLayoutUnit { style().letterSpacing() }; |
| } |
| |
| void LineBuilder::Run::removeTrailingLetterSpacing() |
| { |
| ASSERT(hasTrailingLetterSpacing()); |
| shrinkHorizontally(trailingLetterSpacing()); |
| ASSERT(logicalWidth() > 0 || (!logicalWidth() && style().letterSpacing() >= intMaxForLayoutUnit)); |
| } |
| |
| void LineBuilder::Run::removeTrailingWhitespace() |
| { |
| // According to https://www.w3.org/TR/css-text-3/#white-space-property matrix |
| // Trimmable whitespace is always collapsable so the length of the trailing trimmable whitespace is always 1 (or non-existent). |
| ASSERT(m_textContent->length()); |
| constexpr size_t trailingTrimmableContentLength = 1; |
| m_textContent->shrink(trailingTrimmableContentLength); |
| visuallyCollapseTrailingWhitespace(); |
| } |
| |
| void LineBuilder::Run::visuallyCollapseTrailingWhitespace() |
| { |
| // This is just a visual adjustment, the text length should remain the same. |
| shrinkHorizontally(m_trailingWhitespaceWidth); |
| m_trailingWhitespaceWidth = { }; |
| m_trailingWhitespaceType = TrailingWhitespace::None; |
| |
| if (!isWhitespacePreserved(style())) { |
| ASSERT(m_expansionOpportunityCount); |
| m_expansionOpportunityCount--; |
| } |
| setExpansionBehavior(AllowLeadingExpansion | AllowTrailingExpansion); |
| } |
| |
| void LineBuilder::Run::setExpansionBehavior(ExpansionBehavior expansionBehavior) |
| { |
| ASSERT(isText()); |
| m_expansion.behavior = expansionBehavior; |
| } |
| |
| inline ExpansionBehavior LineBuilder::Run::expansionBehavior() const |
| { |
| ASSERT(isText()); |
| return m_expansion.behavior; |
| } |
| |
| void LineBuilder::Run::setComputedHorizontalExpansion(InlineLayoutUnit logicalExpansion) |
| { |
| ASSERT(isText()); |
| ASSERT(hasExpansionOpportunity()); |
| m_logicalRect.expandHorizontally(logicalExpansion); |
| m_expansion.horizontalExpansion = logicalExpansion; |
| } |
| |
| } |
| } |
| |
| #endif |
