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[LayoutNG] Implement inline margins for atomic inline boxes
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This patch implements inline margins for atomic inline boxes. Inline
margins for non-replaced inline boxes is not included and will be in
following patches.

Also changes not to generate OpenTag/CloseTag NGInlineItem for atomic
inline boxes. Atomic inlines use their margin boxes for inline layout
purposes, while non-replaced inline boxes has different characteristics.
Not generating OpenTag/CloseTag helps single code to handle both cases.

BUG=636993,723135

Review-Url: https://codereview.chromium.org/2883213003
Cr-Commit-Position: refs/heads/master@{#472478}
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@kojiishi
kojiishi authored and Commit bot committed May 17, 2017
1 parent e21aa45 commit 8876859
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Showing 5 changed files with 72 additions and 50 deletions.
4 changes: 4 additions & 0 deletions third_party/WebKit/Source/core/layout/ng/inline/ng_inline_item_result.h
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Original file line number Diff line number Diff line change
Expand Up @@ -5,6 +5,7 @@
#ifndef NGInlineItemResult_h
#define NGInlineItemResult_h

#include "core/layout/ng/geometry/ng_box_strut.h"
#include "core/layout/ng/ng_layout_result.h"
#include "platform/LayoutUnit.h"
#include "platform/fonts/shaping/ShapeResult.h"
Expand Down Expand Up @@ -38,6 +39,9 @@ struct CORE_EXPORT NGInlineItemResult {
// NGLayoutResult for atomic inline items.
RefPtr<NGLayoutResult> layout_result;

// NGBoxStrut for atomic inline items.
NGBoxStrut margins;

NGInlineItemResult();
NGInlineItemResult(unsigned index, unsigned start, unsigned end);
};
Expand Down
82 changes: 46 additions & 36 deletions third_party/WebKit/Source/core/layout/ng/inline/ng_inline_layout_algorithm.cc
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Original file line number Diff line number Diff line change
Expand Up @@ -114,6 +114,15 @@ LayoutUnit NGInlineLayoutAlgorithm::AvailableWidth() const {
return current_opportunity_.InlineSize();
}

// The offset of 'line-left' side.
// https://drafts.csswg.org/css-writing-modes/#line-left
LayoutUnit NGInlineLayoutAlgorithm::LogicalLeftOffset() const {
// TODO(kojii): We need to convert 'line start' to 'line left'. They're
// different in RTL. Maybe there are more where start and left are misused.
return current_opportunity_.InlineStartOffset() -
ConstraintSpace().BfcOffset().inline_offset;
}

bool NGInlineLayoutAlgorithm::CreateLine(
NGInlineItemResults* item_results,
RefPtr<NGInlineBreakToken> break_token) {
Expand Down Expand Up @@ -239,36 +248,40 @@ bool NGInlineLayoutAlgorithm::PlaceItems(
NGTextFragmentBuilder text_builder(Node());
NGInlineBoxState* box =
box_states_.OnBeginPlaceItems(&LineStyle(), baseline_type_);
LayoutUnit inline_size;

// Place items from line-left to line-right along with the baseline.
// Items are already bidi-reordered to the visual order.
LayoutUnit line_left_position = LogicalLeftOffset();
LayoutUnit position = line_left_position;

for (auto& item_result : *line_items) {
const NGInlineItem& item = items[item_result.item_index];
LayoutUnit line_top;
if (item.Type() == NGInlineItem::kText) {
DCHECK(item.GetLayoutObject()->IsText());
DCHECK(!box->text_metrics.IsEmpty());
line_top = box->text_top;
text_builder.SetSize(
{item_result.inline_size, box->text_metrics.LineHeight()});
// Take all used fonts into account if 'line-height: normal'.
if (box->include_used_fonts) {
box->AccumulateUsedFonts(item, item_result.start_offset,
item_result.end_offset, baseline_type_);
}
RefPtr<NGPhysicalTextFragment> text_fragment =
text_builder.ToTextFragment(item_result.item_index,
item_result.start_offset,
item_result.end_offset);
line_box.AddChild(std::move(text_fragment), {position, box->text_top});
} else if (item.Type() == NGInlineItem::kOpenTag) {
box = box_states_.OnOpenTag(item, &line_box, &text_builder);
// Compute text metrics for all inline boxes since even empty inlines
// influence the line height.
// https://drafts.csswg.org/css2/visudet.html#line-height
// TODO(kojii): Review if atomic inline level should have open/close.
if (!item.GetLayoutObject()->IsAtomicInlineLevel())
box->ComputeTextMetrics(*item.Style(), baseline_type_);
continue;
box->ComputeTextMetrics(*item.Style(), baseline_type_);
} else if (item.Type() == NGInlineItem::kCloseTag) {
box = box_states_.OnCloseTag(item, &line_box, box, baseline_type_);
continue;
} else if (item.Type() == NGInlineItem::kAtomicInline) {
line_top =
PlaceAtomicInline(item, &item_result, &line_box, box, &text_builder);
box = PlaceAtomicInline(item, &item_result, position, &line_box,
&text_builder);
} else if (item.Type() == NGInlineItem::kOutOfFlowPositioned) {
// TODO(layout-dev): Report the correct static position for the out of
// flow descendant. We can't do this here yet as it doesn't know the
Expand All @@ -285,18 +298,7 @@ bool NGInlineLayoutAlgorithm::PlaceItems(
continue;
}

RefPtr<NGPhysicalTextFragment> text_fragment = text_builder.ToTextFragment(
item_result.item_index, item_result.start_offset,
item_result.end_offset);

NGLogicalOffset opportunity_offset =
current_opportunity_.InlineStartBlockStartOffset() -
ContainerBfcOffset();
NGLogicalOffset line_offset = {
opportunity_offset.inline_offset + inline_size, line_top};

inline_size += item_result.inline_size;
line_box.AddChild(std::move(text_fragment), line_offset);
position += item_result.inline_size;
}

if (line_box.Children().IsEmpty()) {
Expand Down Expand Up @@ -329,6 +331,9 @@ bool NGInlineLayoutAlgorithm::PlaceItems(
// at 0. Move them to the final baseline position, and set the logical top of
// the line box to the line top.
line_box.MoveChildrenInBlockDirection(baseline);

DCHECK_EQ(line_left_position, LogicalLeftOffset());
LayoutUnit inline_size = position - line_left_position;
line_box.SetInlineSize(inline_size);
container_builder_.AddChild(
line_box.ToLineBoxFragment(),
Expand All @@ -341,30 +346,25 @@ bool NGInlineLayoutAlgorithm::PlaceItems(

// TODO(kojii): Currently, this function does not change item_result, but
// when NG paint is enabled, this will std::move() the LayoutResult.
LayoutUnit NGInlineLayoutAlgorithm::PlaceAtomicInline(
NGInlineBoxState* NGInlineLayoutAlgorithm::PlaceAtomicInline(
const NGInlineItem& item,
NGInlineItemResult* item_result,
LayoutUnit position,
NGLineBoxFragmentBuilder* line_box,
NGInlineBoxState* state,
NGTextFragmentBuilder* text_builder) {
DCHECK(item_result->layout_result);

NGInlineBoxState* box = box_states_.OnOpenTag(item, line_box, text_builder);

// For replaced elements, inline-block elements, and inline-table elements,
// the height is the height of their margin box.
// https://drafts.csswg.org/css2/visudet.html#line-height
NGBoxFragment fragment(
ConstraintSpace().WritingMode(),
ToNGPhysicalBoxFragment(
item_result->layout_result->PhysicalFragment().Get()));
DCHECK(item.Style());
NGBoxStrut margins = ComputeMargins(ConstraintSpace(), *item.Style(),
ConstraintSpace().WritingMode(),
item.Style()->Direction());
LayoutUnit block_size = fragment.BlockSize() + margins.BlockSum();

// TODO(kojii): Try to eliminate the wrapping text fragment and use the
// |fragment| directly. Currently |CopyFragmentDataToLayoutBlockFlow|
// requires a text fragment.
text_builder->SetSize({fragment.InlineSize(), block_size});
LayoutUnit block_size =
fragment.BlockSize() + item_result->margins.BlockSum();

// TODO(kojii): Add baseline position to NGPhysicalFragment.
LayoutBox* layout_box = ToLayoutBox(item.GetLayoutObject());
Expand All @@ -375,12 +375,22 @@ LayoutUnit NGInlineLayoutAlgorithm::PlaceAtomicInline(
baseline_type_, IsFirstLine(), line_direction_mode));

NGLineHeightMetrics metrics(baseline_offset, block_size - baseline_offset);
state->metrics.Unite(metrics);
box->metrics.Unite(metrics);

// TODO(kojii): Figure out what to do with OOF in NGLayoutResult.
// Floats are ok because atomic inlines are BFC?

return -(metrics.ascent - margins.block_start);
// TODO(kojii): Try to eliminate the wrapping text fragment and use the
// |fragment| directly. Currently |CopyFragmentDataToLayoutBlockFlow|
// requires a text fragment.
text_builder->SetSize({fragment.InlineSize(), block_size});
LayoutUnit line_top = item_result->margins.block_start - metrics.ascent;
RefPtr<NGPhysicalTextFragment> text_fragment = text_builder->ToTextFragment(
item_result->item_index, item_result->start_offset,
item_result->end_offset);
line_box->AddChild(std::move(text_fragment), {position, line_top});

return box_states_.OnCloseTag(item, line_box, box, baseline_type_);
}

void NGInlineLayoutAlgorithm::FindNextLayoutOpportunity() {
Expand Down
12 changes: 7 additions & 5 deletions third_party/WebKit/Source/core/layout/ng/inline/ng_inline_layout_algorithm.h
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Original file line number Diff line number Diff line change
Expand Up @@ -64,14 +64,16 @@ class CORE_EXPORT NGInlineLayoutAlgorithm final
const ComputedStyle& FirstLineStyle() const;
const ComputedStyle& LineStyle() const;

LayoutUnit LogicalLeftOffset() const;

void BidiReorder(NGInlineItemResults*);

bool PlaceItems(NGInlineItemResults*, RefPtr<NGInlineBreakToken>);
LayoutUnit PlaceAtomicInline(const NGInlineItem&,
NGInlineItemResult*,
NGLineBoxFragmentBuilder*,
NGInlineBoxState*,
NGTextFragmentBuilder*);
NGInlineBoxState* PlaceAtomicInline(const NGInlineItem&,
NGInlineItemResult*,
LayoutUnit position,
NGLineBoxFragmentBuilder*,
NGTextFragmentBuilder*);

// Finds the next layout opportunity for the next text fragment.
void FindNextLayoutOpportunity();
Expand Down
18 changes: 9 additions & 9 deletions third_party/WebKit/Source/core/layout/ng/inline/ng_inline_node.cc
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Original file line number Diff line number Diff line change
Expand Up @@ -100,26 +100,26 @@ LayoutObject* NGInlineNode::CollectInlines(LayoutObject* start,
// NGInlineLayoutAlgorithm.
builder->Append(NGInlineItem::kFloating, kObjectReplacementCharacter,
nullptr, node);

} else if (node->IsOutOfFlowPositioned()) {
builder->Append(NGInlineItem::kOutOfFlowPositioned,
kObjectReplacementCharacter, nullptr, node);

} else if (node->IsAtomicInlineLevel()) {
// For atomic inlines add a unicode "object replacement character" to
// signal the presence of a non-text object to the unicode bidi algorithm.
builder->Append(NGInlineItem::kAtomicInline, kObjectReplacementCharacter,
node->Style(), node);

} else if (!node->IsInline()) {
// A block box found. End inline and transit to block layout.
return node;

} else {
builder->EnterInline(node);

// For atomic inlines add a unicode "object replacement character" to
// signal the presence of a non-text object to the unicode bidi algorithm.
if (node->IsAtomicInlineLevel()) {
builder->Append(NGInlineItem::kAtomicInline,
kObjectReplacementCharacter, node->Style(), node);
}

// Otherwise traverse to children if they exist.
else if (LayoutObject* child = node->SlowFirstChild()) {
// Traverse to children if they exist.
if (LayoutObject* child = node->SlowFirstChild()) {
node = child;
continue;

Expand Down
6 changes: 6 additions & 0 deletions third_party/WebKit/Source/core/layout/ng/inline/ng_line_breaker.cc
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Original file line number Diff line number Diff line change
Expand Up @@ -13,6 +13,7 @@
#include "core/layout/ng/ng_constraint_space.h"
#include "core/layout/ng/ng_fragment_builder.h"
#include "core/layout/ng/ng_layout_opportunity_iterator.h"
#include "core/layout/ng/ng_length_utils.h"
#include "core/style/ComputedStyle.h"
#include "platform/fonts/shaping/HarfBuzzShaper.h"
#include "platform/fonts/shaping/ShapingLineBreaker.h"
Expand Down Expand Up @@ -225,6 +226,11 @@ void NGLineBreaker::LayoutAtomicInline(const NGInlineItem& item,
ToNGPhysicalBoxFragment(
item_result->layout_result->PhysicalFragment().Get()))
.InlineSize();

item_result->margins =
ComputeMargins(*constraint_space_, style,
constraint_space_->WritingMode(), style.Direction());
item_result->inline_size += item_result->margins.InlineSum();
}

// Handles when the last item overflows.
Expand Down

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