blob: 24c2ad4874b5f091171aee2605ce908655e9a6c8 [file] [log] [blame]
// Copyright 2016 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "third_party/blink/renderer/core/layout/ng/ng_length_utils.h"
#include <algorithm>
#include "base/optional.h"
#include "third_party/blink/renderer/core/layout/layout_box.h"
#include "third_party/blink/renderer/core/layout/layout_table_cell.h"
#include "third_party/blink/renderer/core/layout/ng/ng_block_node.h"
#include "third_party/blink/renderer/core/layout/ng/ng_constraint_space.h"
#include "third_party/blink/renderer/core/layout/ng/ng_constraint_space_builder.h"
#include "third_party/blink/renderer/core/style/computed_style.h"
#include "third_party/blink/renderer/platform/layout_unit.h"
#include "third_party/blink/renderer/platform/length.h"
namespace blink {
bool NeedMinMaxSize(const NGConstraintSpace& constraint_space,
const ComputedStyle& style) {
// This check is technically too broad (fill-available does not need intrinsic
// size computation) but that's a rare case and only affects performance, not
// correctness.
return constraint_space.IsShrinkToFit() || NeedMinMaxSize(style);
}
bool NeedMinMaxSize(const ComputedStyle& style) {
return style.LogicalWidth().IsIntrinsic() ||
style.LogicalMinWidth().IsIntrinsic() ||
style.LogicalMaxWidth().IsIntrinsic();
}
bool NeedMinMaxSizeForContentContribution(WritingMode mode,
const ComputedStyle& style) {
// During the intrinsic sizes pass percentages/calc() are defined to behave
// like 'auto'. As a result we need to calculate the intrinsic sizes for any
// children with percentages. E.g.
// <div style="float:left;">
// <div style="width:30%;">text text</div>
// </div>
if (mode == WritingMode::kHorizontalTb) {
return style.Width().IsIntrinsicOrAuto() ||
style.Width().IsPercentOrCalc() || style.MinWidth().IsIntrinsic() ||
style.MaxWidth().IsIntrinsic();
}
return style.Height().IsIntrinsicOrAuto() ||
style.Height().IsPercentOrCalc() || style.MinHeight().IsIntrinsic() ||
style.MaxHeight().IsIntrinsic();
}
LayoutUnit ResolveInlineLength(const NGConstraintSpace& constraint_space,
const ComputedStyle& style,
const base::Optional<MinMaxSize>& min_and_max,
const Length& length,
LengthResolveType type,
LengthResolvePhase phase) {
DCHECK_GE(constraint_space.AvailableSize().inline_size, LayoutUnit());
DCHECK_GE(constraint_space.PercentageResolutionSize().inline_size,
LayoutUnit());
DCHECK_EQ(constraint_space.GetWritingMode(), style.GetWritingMode());
if (constraint_space.IsAnonymous())
return constraint_space.AvailableSize().inline_size;
if (length.IsMaxSizeNone()) {
DCHECK_EQ(type, LengthResolveType::kMaxSize);
return LayoutUnit::Max();
}
NGBoxStrut border_and_padding = ComputeBorders(constraint_space, style) +
ComputePadding(constraint_space, style);
if (type == LengthResolveType::kMinSize && length.IsAuto())
return border_and_padding.InlineSum();
// Check if we shouldn't resolve a percentage/calc() if we are in the
// intrinsic sizes phase.
if (phase == LengthResolvePhase::kIntrinsic && length.IsPercentOrCalc()) {
// min-width/min-height should be "0", i.e. no min limit is applied.
if (type == LengthResolveType::kMinSize)
return border_and_padding.InlineSum();
// max-width/max-height becomes "infinity", i.e. no max limit is applied.
if (type == LengthResolveType::kMaxSize)
return LayoutUnit::Max();
}
switch (length.GetType()) {
case kAuto:
case kFillAvailable: {
LayoutUnit content_size = constraint_space.AvailableSize().inline_size;
NGBoxStrut margins = ComputeMarginsForSelf(constraint_space, style);
return std::max(border_and_padding.InlineSum(),
content_size - margins.InlineSum());
}
case kPercent:
case kFixed:
case kCalculated: {
LayoutUnit percentage_resolution_size =
constraint_space.PercentageResolutionSize().inline_size;
LayoutUnit value = ValueForLength(length, percentage_resolution_size);
if (style.BoxSizing() == EBoxSizing::kContentBox) {
value += border_and_padding.InlineSum();
} else {
value = std::max(border_and_padding.InlineSum(), value);
}
return value;
}
case kMinContent:
case kMaxContent:
case kFitContent: {
DCHECK(min_and_max.has_value());
LayoutUnit available_size = constraint_space.AvailableSize().inline_size;
LayoutUnit value;
if (length.IsMinContent()) {
value = min_and_max->min_size;
} else if (length.IsMaxContent() || available_size == LayoutUnit::Max()) {
// If the available space is infinite, fit-content resolves to
// max-content. See css-sizing section 2.1.
value = min_and_max->max_size;
} else {
NGBoxStrut margins = ComputeMarginsForSelf(constraint_space, style);
LayoutUnit fill_available =
std::max(LayoutUnit(), available_size - margins.InlineSum());
value = min_and_max->ShrinkToFit(fill_available);
}
return value;
}
case kDeviceWidth:
case kDeviceHeight:
case kExtendToZoom:
NOTREACHED() << "These should only be used for viewport definitions";
FALLTHROUGH;
case kMaxSizeNone:
default:
NOTREACHED();
return border_and_padding.InlineSum();
}
}
LayoutUnit ResolveBlockLength(const NGConstraintSpace& constraint_space,
const ComputedStyle& style,
const Length& length,
LayoutUnit content_size,
LengthResolveType type,
LengthResolvePhase phase) {
DCHECK_EQ(constraint_space.GetWritingMode(), style.GetWritingMode());
if (constraint_space.IsAnonymous())
return content_size;
if (length.IsMaxSizeNone()) {
DCHECK_EQ(type, LengthResolveType::kMaxSize);
return LayoutUnit::Max();
}
NGBoxStrut border_and_padding = ComputeBorders(constraint_space, style) +
ComputePadding(constraint_space, style);
if (type == LengthResolveType::kMinSize && length.IsAuto())
return border_and_padding.BlockSum();
bool is_percentage_indefinite =
constraint_space.PercentageResolutionSize().block_size ==
NGSizeIndefinite;
// Check if we can't/shouldn't resolve a percentage/calc() - because the
// percentage resolution size is indefinite or because we are in the
// intrinsic sizes phase.
if ((phase == LengthResolvePhase::kIntrinsic || is_percentage_indefinite) &&
length.IsPercentOrCalc()) {
// min-width/min-height should be "0", i.e. no min limit is applied.
if (type == LengthResolveType::kMinSize)
return border_and_padding.BlockSum();
// max-width/max-height becomes "infinity", i.e. no max limit is applied.
if (type == LengthResolveType::kMaxSize)
return LayoutUnit::Max();
// width/height becomes "auto", so we can just return the content size.
DCHECK_EQ(type, LengthResolveType::kContentSize);
return content_size;
}
switch (length.GetType()) {
case kFillAvailable: {
LayoutUnit content_size = constraint_space.AvailableSize().block_size;
NGBoxStrut margins = ComputeMarginsForSelf(constraint_space, style);
return std::max(border_and_padding.BlockSum(),
content_size - margins.BlockSum());
}
case kPercent:
case kFixed:
case kCalculated: {
LayoutUnit percentage_resolution_size =
constraint_space.PercentageResolutionSize().block_size;
LayoutUnit value = ValueForLength(length, percentage_resolution_size);
if (style.BoxSizing() == EBoxSizing::kContentBox) {
value += border_and_padding.BlockSum();
} else {
value = std::max(border_and_padding.BlockSum(), value);
}
return value;
}
case kAuto:
case kMinContent:
case kMaxContent:
case kFitContent:
#if DCHECK_IS_ON()
// Due to how content_size is calculated, it should always include border
// and padding. We cannot check for this if we are block-fragmented,
// though, because then the block-start border/padding may be in a
// different fragmentainer than the block-end border/padding.
if (content_size != LayoutUnit(-1) &&
!constraint_space.HasBlockFragmentation())
DCHECK_GE(content_size, border_and_padding.BlockSum());
#endif // DCHECK_IS_ON()
return content_size;
case kDeviceWidth:
case kDeviceHeight:
case kExtendToZoom:
NOTREACHED() << "These should only be used for viewport definitions";
FALLTHROUGH;
case kMaxSizeNone:
default:
NOTREACHED();
return border_and_padding.BlockSum();
}
}
LayoutUnit ResolveMarginPaddingLength(const NGConstraintSpace& constraint_space,
const Length& length) {
DCHECK_GE(constraint_space.AvailableSize().inline_size, LayoutUnit());
// Margins and padding always get computed relative to the inline size:
// https://www.w3.org/TR/CSS2/box.html#value-def-margin-width
// https://www.w3.org/TR/CSS2/box.html#value-def-padding-width
switch (length.GetType()) {
case kAuto:
return LayoutUnit();
case kPercent:
case kFixed:
case kCalculated: {
LayoutUnit percentage_resolution_size =
constraint_space.PercentageResolutionInlineSizeForParentWritingMode();
return ValueForLength(length, percentage_resolution_size);
}
case kMinContent:
case kMaxContent:
case kFillAvailable:
case kFitContent:
case kExtendToZoom:
case kDeviceWidth:
case kDeviceHeight:
case kMaxSizeNone:
FALLTHROUGH;
default:
NOTREACHED();
return LayoutUnit();
}
}
MinMaxSize ComputeMinAndMaxContentContribution(
WritingMode writing_mode,
const ComputedStyle& style,
const base::Optional<MinMaxSize>& min_and_max) {
// Synthesize a zero-sized constraint space for passing to
// ResolveInlineLength.
// The constraint space's writing mode has to match the style, so we can't
// use the passed-in mode here.
NGConstraintSpaceBuilder builder(
style.GetWritingMode(),
/* icb_size */ {NGSizeIndefinite, NGSizeIndefinite});
scoped_refptr<NGConstraintSpace> space =
builder.ToConstraintSpace(style.GetWritingMode());
LayoutUnit content_size =
min_and_max ? min_and_max->max_size : NGSizeIndefinite;
MinMaxSize computed_sizes;
Length inline_size = writing_mode == WritingMode::kHorizontalTb
? style.Width()
: style.Height();
if (inline_size.IsAuto() || inline_size.IsPercentOrCalc()) {
CHECK(min_and_max.has_value());
computed_sizes = *min_and_max;
} else {
if (IsParallelWritingMode(writing_mode, style.GetWritingMode())) {
computed_sizes.min_size = computed_sizes.max_size = ResolveInlineLength(
*space, style, min_and_max, inline_size,
LengthResolveType::kContentSize, LengthResolvePhase::kIntrinsic);
} else {
computed_sizes.min_size = computed_sizes.max_size = ResolveBlockLength(
*space, style, inline_size, content_size,
LengthResolveType::kContentSize, LengthResolvePhase::kIntrinsic);
}
}
Length max_length = writing_mode == WritingMode::kHorizontalTb
? style.MaxWidth()
: style.MaxHeight();
LayoutUnit max;
if (IsParallelWritingMode(writing_mode, style.GetWritingMode())) {
max = ResolveInlineLength(*space, style, min_and_max, max_length,
LengthResolveType::kMaxSize,
LengthResolvePhase::kIntrinsic);
} else {
max = ResolveBlockLength(*space, style, max_length, content_size,
LengthResolveType::kMaxSize,
LengthResolvePhase::kIntrinsic);
}
computed_sizes.min_size = std::min(computed_sizes.min_size, max);
computed_sizes.max_size = std::min(computed_sizes.max_size, max);
Length min_length = writing_mode == WritingMode::kHorizontalTb
? style.MinWidth()
: style.MinHeight();
LayoutUnit min;
if (IsParallelWritingMode(writing_mode, style.GetWritingMode())) {
min = ResolveInlineLength(*space, style, min_and_max, min_length,
LengthResolveType::kMinSize,
LengthResolvePhase::kIntrinsic);
} else {
min = ResolveBlockLength(*space, style, min_length, content_size,
LengthResolveType::kMinSize,
LengthResolvePhase::kIntrinsic);
}
computed_sizes.min_size = std::max(computed_sizes.min_size, min);
computed_sizes.max_size = std::max(computed_sizes.max_size, min);
return computed_sizes;
}
MinMaxSize ComputeMinAndMaxContentContribution(
WritingMode writing_mode,
NGLayoutInputNode node,
const MinMaxSizeInput& input,
const NGConstraintSpace* constraint_space) {
// Tables are special; even if a width is specified, they may end up being
// sized different. So we just always let the table code handle this.
// Replaced elements may size themselves using aspect ratios and block sizes,
// so we pass that on as well.
LayoutObject* layout_object = node.GetLayoutObject();
if (layout_object->IsTable() || layout_object->IsTablePart() ||
layout_object->IsLayoutReplaced()) {
LayoutBox* box = ToLayoutBox(layout_object);
return {box->MinPreferredLogicalWidth(), box->MaxPreferredLogicalWidth()};
}
base::Optional<MinMaxSize> minmax;
if (NeedMinMaxSizeForContentContribution(writing_mode, node.Style())) {
scoped_refptr<NGConstraintSpace> adjusted_constraint_space;
if (constraint_space) {
// TODO(layout-ng): Check if our constraint space produces spec-compliant
// outputs.
// It is important to set a floats bfc offset so that we don't get a
// partial layout. It is also important that we shrink to fit, by
// definition.
NGConstraintSpaceBuilder builder(*constraint_space);
builder.SetAvailableSize(constraint_space->AvailableSize())
.SetPercentageResolutionSize(
constraint_space->PercentageResolutionSize())
.SetFloatsBfcOffset(NGBfcOffset())
.SetIsNewFormattingContext(node.CreatesNewFormattingContext())
.SetIsShrinkToFit(true);
adjusted_constraint_space =
builder.ToConstraintSpace(node.Style().GetWritingMode());
constraint_space = adjusted_constraint_space.get();
}
minmax = node.ComputeMinMaxSize(writing_mode, input, constraint_space);
}
return ComputeMinAndMaxContentContribution(writing_mode, node.Style(),
minmax);
}
LayoutUnit ComputeInlineSizeForFragment(
const NGConstraintSpace& space,
const ComputedStyle& style,
const base::Optional<MinMaxSize>& min_and_max) {
if (space.IsFixedSizeInline())
return space.AvailableSize().inline_size;
Length logical_width = style.LogicalWidth();
if (logical_width.IsAuto() && space.IsShrinkToFit())
logical_width = Length(kFitContent);
LayoutUnit extent = ResolveInlineLength(
space, style, min_and_max, logical_width, LengthResolveType::kContentSize,
LengthResolvePhase::kLayout);
LayoutUnit max = ResolveInlineLength(
space, style, min_and_max, style.LogicalMaxWidth(),
LengthResolveType::kMaxSize, LengthResolvePhase::kLayout);
LayoutUnit min = ResolveInlineLength(
space, style, min_and_max, style.LogicalMinWidth(),
LengthResolveType::kMinSize, LengthResolvePhase::kLayout);
return ConstrainByMinMax(extent, min, max);
}
LayoutUnit ComputeBlockSizeForFragment(
const NGConstraintSpace& constraint_space,
const ComputedStyle& style,
LayoutUnit content_size) {
if (constraint_space.IsFixedSizeBlock())
return constraint_space.AvailableSize().block_size;
if (style.Display() == EDisplay::kTableCell) {
// All handled by the table layout code or not applicable.
return content_size;
}
LayoutUnit extent = ResolveBlockLength(
constraint_space, style, style.LogicalHeight(), content_size,
LengthResolveType::kContentSize, LengthResolvePhase::kLayout);
if (extent == NGSizeIndefinite) {
DCHECK_EQ(content_size, NGSizeIndefinite);
return extent;
}
LayoutUnit max = ResolveBlockLength(
constraint_space, style, style.LogicalMaxHeight(), content_size,
LengthResolveType::kMaxSize, LengthResolvePhase::kLayout);
LayoutUnit min = ResolveBlockLength(
constraint_space, style, style.LogicalMinHeight(), content_size,
LengthResolveType::kMinSize, LengthResolvePhase::kLayout);
return ConstrainByMinMax(extent, min, max);
}
// Computes size for a replaced element.
NGLogicalSize ComputeReplacedSize(
const NGLayoutInputNode& node,
const NGConstraintSpace& space,
const base::Optional<MinMaxSize>& child_minmax) {
DCHECK(node.IsReplaced());
NGLogicalSize replaced_size;
NGLogicalSize default_intrinsic_size;
base::Optional<LayoutUnit> computed_inline_size;
base::Optional<LayoutUnit> computed_block_size;
NGLogicalSize aspect_ratio;
node.IntrinsicSize(&default_intrinsic_size, &computed_inline_size,
&computed_block_size, &aspect_ratio);
const ComputedStyle& style = node.Style();
Length inline_length = style.LogicalWidth();
Length block_length = style.LogicalHeight();
// Compute inline size
if (inline_length.IsAuto()) {
if (block_length.IsAuto() || aspect_ratio.IsEmpty()) {
// Use intrinsic values if inline_size cannot be computed from block_size.
if (computed_inline_size.has_value())
replaced_size.inline_size = computed_inline_size.value();
else
replaced_size.inline_size = default_intrinsic_size.inline_size;
replaced_size.inline_size +=
(ComputeBorders(space, style) + ComputePadding(space, style))
.InlineSum();
} else {
// inline_size is computed from block_size.
replaced_size.inline_size =
ResolveBlockLength(
space, style, block_length, default_intrinsic_size.block_size,
LengthResolveType::kContentSize, LengthResolvePhase::kLayout) *
aspect_ratio.inline_size / aspect_ratio.block_size;
}
} else {
// inline_size is resolved directly.
replaced_size.inline_size = ResolveInlineLength(
space, style, child_minmax, inline_length,
LengthResolveType::kContentSize, LengthResolvePhase::kLayout);
}
// Compute block size
if (block_length.IsAuto()) {
if (inline_length.IsAuto() || aspect_ratio.IsEmpty()) {
// Use intrinsic values if block_size cannot be computed from inline_size.
if (computed_block_size.has_value())
replaced_size.block_size = LayoutUnit(computed_block_size.value());
else
replaced_size.block_size = default_intrinsic_size.block_size;
replaced_size.block_size +=
(ComputeBorders(space, style) + ComputePadding(space, style))
.BlockSum();
} else {
// block_size is computed from inline_size.
replaced_size.block_size =
ResolveInlineLength(space, style, child_minmax, inline_length,
LengthResolveType::kContentSize,
LengthResolvePhase::kLayout) *
aspect_ratio.block_size / aspect_ratio.inline_size;
}
} else {
replaced_size.block_size = ResolveBlockLength(
space, style, block_length, default_intrinsic_size.block_size,
LengthResolveType::kContentSize, LengthResolvePhase::kLayout);
}
return replaced_size;
}
int ResolveUsedColumnCount(int computed_count,
LayoutUnit computed_size,
LayoutUnit used_gap,
LayoutUnit available_size) {
if (computed_size == NGSizeIndefinite) {
DCHECK(computed_count);
return computed_count;
}
DCHECK_GT(computed_size, LayoutUnit());
int count_from_width =
((available_size + used_gap) / (computed_size + used_gap)).ToInt();
count_from_width = std::max(1, count_from_width);
if (!computed_count)
return count_from_width;
return std::max(1, std::min(computed_count, count_from_width));
}
int ResolveUsedColumnCount(LayoutUnit available_size,
const ComputedStyle& style) {
LayoutUnit computed_column_inline_size =
style.HasAutoColumnWidth()
? NGSizeIndefinite
: std::max(LayoutUnit(1), LayoutUnit(style.ColumnWidth()));
LayoutUnit gap = ResolveUsedColumnGap(available_size, style);
int computed_count = style.ColumnCount();
return ResolveUsedColumnCount(computed_count, computed_column_inline_size,
gap, available_size);
}
LayoutUnit ResolveUsedColumnInlineSize(int computed_count,
LayoutUnit computed_size,
LayoutUnit used_gap,
LayoutUnit available_size) {
int used_count = ResolveUsedColumnCount(computed_count, computed_size,
used_gap, available_size);
return std::max(((available_size + used_gap) / used_count) - used_gap,
LayoutUnit());
}
LayoutUnit ResolveUsedColumnInlineSize(LayoutUnit available_size,
const ComputedStyle& style) {
// Should only attempt to resolve this if columns != auto.
DCHECK(!style.HasAutoColumnCount() || !style.HasAutoColumnWidth());
LayoutUnit computed_size =
style.HasAutoColumnWidth()
? NGSizeIndefinite
: std::max(LayoutUnit(1), LayoutUnit(style.ColumnWidth()));
int computed_count = style.HasAutoColumnCount() ? 0 : style.ColumnCount();
LayoutUnit used_gap = ResolveUsedColumnGap(available_size, style);
return ResolveUsedColumnInlineSize(computed_count, computed_size, used_gap,
available_size);
}
LayoutUnit ResolveUsedColumnGap(LayoutUnit available_size,
const ComputedStyle& style) {
if (style.ColumnGap().IsNormal())
return LayoutUnit(style.GetFontDescription().ComputedPixelSize());
return ValueForLength(style.ColumnGap().GetLength(), available_size);
}
NGPhysicalBoxStrut ComputePhysicalMargins(
const NGConstraintSpace& constraint_space,
const ComputedStyle& style) {
if (constraint_space.IsAnonymous())
return NGPhysicalBoxStrut();
NGPhysicalBoxStrut physical_dim;
physical_dim.left =
ResolveMarginPaddingLength(constraint_space, style.MarginLeft());
physical_dim.right =
ResolveMarginPaddingLength(constraint_space, style.MarginRight());
physical_dim.top =
ResolveMarginPaddingLength(constraint_space, style.MarginTop());
physical_dim.bottom =
ResolveMarginPaddingLength(constraint_space, style.MarginBottom());
return physical_dim;
}
NGBoxStrut ComputeMarginsFor(const NGConstraintSpace& constraint_space,
const ComputedStyle& style,
const NGConstraintSpace& compute_for) {
return ComputePhysicalMargins(constraint_space, style)
.ConvertToLogical(compute_for.GetWritingMode(), compute_for.Direction());
}
NGBoxStrut ComputeMarginsForContainer(const NGConstraintSpace& constraint_space,
const ComputedStyle& style) {
return ComputePhysicalMargins(constraint_space, style)
.ConvertToLogical(constraint_space.GetWritingMode(),
constraint_space.Direction());
}
NGBoxStrut ComputeMarginsForVisualContainer(
const NGConstraintSpace& constraint_space,
const ComputedStyle& style) {
return ComputePhysicalMargins(constraint_space, style)
.ConvertToLogical(constraint_space.GetWritingMode(), TextDirection::kLtr);
}
NGBoxStrut ComputeMarginsForSelf(const NGConstraintSpace& constraint_space,
const ComputedStyle& style) {
return ComputePhysicalMargins(constraint_space, style)
.ConvertToLogical(style.GetWritingMode(), style.Direction());
}
NGBoxStrut ComputeMinMaxMargins(const ComputedStyle& parent_style,
NGLayoutInputNode child) {
// An inline child just produces line-boxes which don't have any margins.
if (child.IsInline())
return NGBoxStrut();
Length inline_start_margin_length =
child.Style().MarginStartUsing(parent_style);
Length inline_end_margin_length = child.Style().MarginEndUsing(parent_style);
// TODO(ikilpatrick): We may want to re-visit calculated margins at some
// point. Currently "margin-left: calc(10px + 50%)" will resolve to 0px, but
// 10px would be more correct, (as percentages resolve to zero).
NGBoxStrut margins;
if (inline_start_margin_length.IsFixed())
margins.inline_start = LayoutUnit(inline_start_margin_length.Value());
if (inline_end_margin_length.IsFixed())
margins.inline_end = LayoutUnit(inline_end_margin_length.Value());
return margins;
}
NGBoxStrut ComputeBorders(const NGConstraintSpace& constraint_space,
const ComputedStyle& style) {
// If we are producing an anonymous fragment (e.g. a column) we shouldn't
// have any borders.
if (constraint_space.IsAnonymous())
return NGBoxStrut();
NGBoxStrut borders;
borders.inline_start = LayoutUnit(style.BorderStartWidth());
borders.inline_end = LayoutUnit(style.BorderEndWidth());
borders.block_start = LayoutUnit(style.BorderBeforeWidth());
borders.block_end = LayoutUnit(style.BorderAfterWidth());
return borders;
}
NGBoxStrut ComputePadding(const NGConstraintSpace& constraint_space,
const ComputedStyle& style) {
// If we are producing an anonymous fragment (e.g. a column) we shouldn't
// have any padding.
if (constraint_space.IsAnonymous())
return NGBoxStrut();
NGBoxStrut padding;
padding.inline_start =
ResolveMarginPaddingLength(constraint_space, style.PaddingStart());
padding.inline_end =
ResolveMarginPaddingLength(constraint_space, style.PaddingEnd());
padding.block_start =
ResolveMarginPaddingLength(constraint_space, style.PaddingBefore());
padding.block_end =
ResolveMarginPaddingLength(constraint_space, style.PaddingAfter());
return padding;
}
void ApplyAutoMargins(const ComputedStyle& style,
const ComputedStyle& containing_block_style,
LayoutUnit available_inline_size,
LayoutUnit inline_size,
NGBoxStrut* margins) {
DCHECK(margins) << "Margins cannot be NULL here";
const LayoutUnit used_space = inline_size + margins->InlineSum();
const LayoutUnit available_space = available_inline_size - used_space;
if (available_space > LayoutUnit()) {
bool start_auto = style.MarginStartUsing(containing_block_style).IsAuto();
bool end_auto = style.MarginEndUsing(containing_block_style).IsAuto();
enum EBlockAlignment { kStart, kCenter, kEnd };
EBlockAlignment alignment;
if (start_auto || end_auto) {
alignment = start_auto ? (end_auto ? kCenter : kEnd) : kStart;
} else {
// If none of the inline margins are auto, look for -webkit- text-align
// values (which are really about block alignment). These are typically
// mapped from the legacy "align" HTML attribute.
switch (containing_block_style.GetTextAlign()) {
case ETextAlign::kWebkitLeft:
alignment =
containing_block_style.IsLeftToRightDirection() ? kStart : kEnd;
break;
case ETextAlign::kWebkitRight:
alignment =
containing_block_style.IsLeftToRightDirection() ? kEnd : kStart;
break;
case ETextAlign::kWebkitCenter:
alignment = kCenter;
break;
default:
alignment = kStart;
break;
}
}
if (alignment == kCenter)
margins->inline_start += available_space / 2;
else if (alignment == kEnd)
margins->inline_start += available_space;
}
margins->inline_end =
available_inline_size - inline_size - margins->inline_start;
}
LayoutUnit LineOffsetForTextAlign(ETextAlign text_align,
TextDirection direction,
LayoutUnit space_left,
LayoutUnit trailing_spaces_width) {
bool is_ltr = IsLtr(direction);
if (text_align == ETextAlign::kStart || text_align == ETextAlign::kJustify)
text_align = is_ltr ? ETextAlign::kLeft : ETextAlign::kRight;
else if (text_align == ETextAlign::kEnd)
text_align = is_ltr ? ETextAlign::kRight : ETextAlign::kLeft;
switch (text_align) {
case ETextAlign::kLeft:
case ETextAlign::kWebkitLeft: {
// The direction of the block should determine what happens with wide
// lines. In particular with RTL blocks, wide lines should still spill
// out to the left.
if (is_ltr)
return LayoutUnit();
return space_left.ClampPositiveToZero();
}
case ETextAlign::kRight:
case ETextAlign::kWebkitRight: {
// In RTL, trailing spaces appear on the left of the line.
if (UNLIKELY(!is_ltr))
return space_left - trailing_spaces_width;
// Wide lines spill out of the block based off direction.
// So even if text-align is right, if direction is LTR, wide lines
// should overflow out of the right side of the block.
if (space_left > LayoutUnit())
return space_left;
return LayoutUnit();
}
case ETextAlign::kCenter:
case ETextAlign::kWebkitCenter: {
if (is_ltr)
return (space_left / 2).ClampNegativeToZero();
// In RTL, trailing spaces appear on the left of the line.
if (space_left > LayoutUnit())
return (space_left / 2).ClampNegativeToZero() - trailing_spaces_width;
// In RTL, wide lines should spill out to the left, same as kRight.
return space_left - trailing_spaces_width;
}
default:
NOTREACHED();
return LayoutUnit();
}
}
LayoutUnit InlineOffsetForTextAlign(const ComputedStyle& container_style,
LayoutUnit space_left) {
TextDirection direction = container_style.Direction();
LayoutUnit line_offset = LineOffsetForTextAlign(
container_style.GetTextAlign(), direction, space_left, LayoutUnit());
return IsLtr(direction) ? line_offset : space_left - line_offset;
}
LayoutUnit ConstrainByMinMax(LayoutUnit length,
LayoutUnit min,
LayoutUnit max) {
return std::max(min, std::min(length, max));
}
NGBoxStrut CalculateBorderScrollbarPadding(
const NGConstraintSpace& constraint_space,
const NGBlockNode node) {
const ComputedStyle& style = node.Style();
// If we are producing an anonymous fragment (e.g. a column), it has no
// borders, padding or scrollbars. Using the ones from the container can only
// cause trouble.
if (constraint_space.IsAnonymous())
return NGBoxStrut();
NGBoxStrut border_intrinsic_padding;
if (node.GetLayoutObject()->IsTableCell()) {
// Use values calculated by the table layout code
const LayoutTableCell* cell = ToLayoutTableCell(node.GetLayoutObject());
// TODO(karlo): intrinsic padding can sometimes be negative; that
// seems insane, but works in the old code; in NG it trips
// DCHECKs.
border_intrinsic_padding = NGBoxStrut(
cell->BorderStart(), cell->BorderEnd(),
cell->BorderBefore() + LayoutUnit(cell->IntrinsicPaddingBefore()),
cell->BorderAfter() + LayoutUnit(cell->IntrinsicPaddingAfter()));
} else {
border_intrinsic_padding = ComputeBorders(constraint_space, style);
}
return border_intrinsic_padding + ComputePadding(constraint_space, style) +
node.GetScrollbarSizes();
}
NGLogicalSize CalculateContentBoxSize(
const NGLogicalSize border_box_size,
const NGBoxStrut& border_scrollbar_padding) {
NGLogicalSize size = border_box_size;
size.inline_size -= border_scrollbar_padding.InlineSum();
size.inline_size = std::max(size.inline_size, LayoutUnit());
// Our calculated block-axis size may still be indefinite. If so, just leave
// the size as NGSizeIndefinite instead of subtracting borders and padding.
if (size.block_size != NGSizeIndefinite) {
size.block_size -= border_scrollbar_padding.BlockSum();
size.block_size = std::max(size.block_size, LayoutUnit());
}
return size;
}
} // namespace blink