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// Copyright 2015 Google Inc. All Rights Reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#include "cobalt/layout/inline_container_box.h"
#include <limits>
#include "cobalt/cssom/keyword_value.h"
#include "cobalt/layout/line_box.h"
#include "cobalt/layout/used_style.h"
namespace cobalt {
namespace layout {
InlineContainerBox::InlineContainerBox(
const scoped_refptr<cssom::CSSComputedStyleDeclaration>&
css_computed_style_declaration,
UsedStyleProvider* used_style_provider,
LayoutStatTracker* layout_stat_tracker)
: ContainerBox(css_computed_style_declaration, used_style_provider,
layout_stat_tracker),
should_collapse_leading_white_space_(false),
should_collapse_trailing_white_space_(false),
has_leading_white_space_(false),
has_trailing_white_space_(false),
is_collapsed_(false),
justifies_line_existence_(false),
first_box_justifying_line_existence_index_(0),
used_font_(used_style_provider->GetUsedFontList(
css_computed_style_declaration->data()->font_family(),
css_computed_style_declaration->data()->font_size(),
css_computed_style_declaration->data()->font_style(),
css_computed_style_declaration->data()->font_weight())) {}
InlineContainerBox::~InlineContainerBox() {}
Box::Level InlineContainerBox::GetLevel() const { return kInlineLevel; }
bool InlineContainerBox::TryAddChild(const scoped_refptr<Box>& child_box) {
switch (child_box->GetLevel()) {
case kBlockLevel:
if (!child_box->IsAbsolutelyPositioned()) {
// Only inline-level boxes are allowed as in-flow children of an inline
// container box.
return false;
}
// Fall through if out-of-flow.
case kInlineLevel:
// If the inline container box already contains a line break, then no
// additional children can be added to it.
if (HasTrailingLineBreak()) {
return false;
}
PushBackDirectChild(child_box);
return true;
default:
NOTREACHED();
return false;
}
}
scoped_refptr<ContainerBox> InlineContainerBox::TrySplitAtEnd() {
scoped_refptr<InlineContainerBox> box_after_split(
new InlineContainerBox(css_computed_style_declaration(),
used_style_provider(), layout_stat_tracker()));
// When an inline box is split, margins, borders, and padding have no visual
// effect where the split occurs.
// https://www.w3.org/TR/CSS21/visuren.html#inline-formatting
// TODO: Implement the above comment.
return box_after_split;
}
LayoutUnit InlineContainerBox::GetInlineLevelBoxHeight() const {
return line_height_;
}
LayoutUnit InlineContainerBox::GetInlineLevelTopMargin() const {
return inline_top_margin_;
}
void InlineContainerBox::UpdateContentSizeAndMargins(
const LayoutParams& layout_params) {
// Lay out child boxes as one line without width constraints and white space
// trimming.
const render_tree::FontMetrics& font_metrics = used_font_->GetFontMetrics();
LayoutUnit box_top_height = LayoutUnit(font_metrics.ascent());
LineBox line_box(box_top_height, true, computed_style()->line_height(),
font_metrics, should_collapse_leading_white_space_,
should_collapse_trailing_white_space_, layout_params,
kLeftToRightBaseDirection, cssom::KeywordValue::GetLeft(),
computed_style()->font_size(), LayoutUnit(), LayoutUnit());
for (Boxes::const_iterator child_box_iterator = child_boxes().begin();
child_box_iterator != child_boxes().end(); ++child_box_iterator) {
line_box.BeginAddChildAndMaybeOverflow(*child_box_iterator);
}
line_box.EndUpdates();
// Although the spec says:
//
// The "width" property does not apply.
// https://www.w3.org/TR/CSS21/visudet.html#inline-width
//
// ...it is not the entire truth. It merely means that we have to ignore
// the computed value of "width". Instead we use the shrink-to-fit width of
// a hypothetical line box that contains all children. Later on this allow
// to apply the following rule:
//
// When an inline box exceeds the width of a line box, it is split into
// several boxes.
// https://www.w3.org/TR/CSS21/visuren.html#inline-formatting
set_width(line_box.shrink_to_fit_width());
base::optional<LayoutUnit> maybe_margin_left = GetUsedMarginLeftIfNotAuto(
computed_style(), layout_params.containing_block_size);
base::optional<LayoutUnit> maybe_margin_right = GetUsedMarginRightIfNotAuto(
computed_style(), layout_params.containing_block_size);
// A computed value of "auto" for "margin-left" or "margin-right" becomes
// a used value of "0".
// https://www.w3.org/TR/CSS21/visudet.html#inline-width
set_margin_left(maybe_margin_left.value_or(LayoutUnit()));
set_margin_right(maybe_margin_right.value_or(LayoutUnit()));
// The "height" property does not apply. The height of the content area should
// be based on the font, but this specification does not specify how. [...]
// However, we suggest that the height is chosen such that the content area
// is just high enough for [...] the maximum ascenders and descenders, of all
// the fonts in the element.
// https://www.w3.org/TR/CSS21/visudet.html#inline-non-replaced
//
// Above definition of used height matches the height of hypothetical line box
// that contains all children.
set_height(LayoutUnit(font_metrics.em_box_height()));
// On a non-replaced inline element, 'line-height' specifies the height that
// is used in the calculation of the line box height.
// https://www.w3.org/TR/CSS21/visudet.html#propdef-line-height
line_height_ = line_box.height();
// Vertical margins will not have any effect on non-replaced inline elements.
// https://www.w3.org/TR/CSS21/box.html#margin-properties
set_margin_top(LayoutUnit());
set_margin_bottom(LayoutUnit());
inline_top_margin_ = line_box.baseline_offset_from_top() - line_box.top() -
border_top_width() - padding_top();
has_leading_white_space_ = line_box.HasLeadingWhiteSpace();
has_trailing_white_space_ = line_box.HasTrailingWhiteSpace();
is_collapsed_ = line_box.IsCollapsed();
justifies_line_existence_ =
line_box.LineExists() || HasNonZeroMarginOrBorderOrPadding();
first_box_justifying_line_existence_index_ =
line_box.GetFirstBoxJustifyingLineExistenceIndex();
baseline_offset_from_margin_box_top_ = line_box.baseline_offset_from_top();
}
WrapResult InlineContainerBox::TryWrapAt(
WrapAtPolicy wrap_at_policy, WrapOpportunityPolicy wrap_opportunity_policy,
bool is_line_existence_justified, LayoutUnit available_width,
bool should_collapse_trailing_white_space) {
DCHECK(!IsAbsolutelyPositioned());
DCHECK(is_line_existence_justified || justifies_line_existence_);
switch (wrap_at_policy) {
case kWrapAtPolicyBefore:
return TryWrapAtBefore(wrap_opportunity_policy,
is_line_existence_justified, available_width,
should_collapse_trailing_white_space);
case kWrapAtPolicyLastOpportunityWithinWidth:
return TryWrapAtLastOpportunityWithinWidth(
wrap_opportunity_policy, is_line_existence_justified, available_width,
should_collapse_trailing_white_space);
case kWrapAtPolicyLastOpportunity:
return TryWrapAtLastOpportunityBeforeIndex(
child_boxes().size(), wrap_opportunity_policy,
is_line_existence_justified, available_width,
should_collapse_trailing_white_space);
case kWrapAtPolicyFirstOpportunity:
return TryWrapAtFirstOpportunity(
wrap_opportunity_policy, is_line_existence_justified, available_width,
should_collapse_trailing_white_space);
default:
NOTREACHED();
return kWrapResultNoWrap;
}
}
Box* InlineContainerBox::GetSplitSibling() const { return split_sibling_; }
bool InlineContainerBox::DoesFulfillEllipsisPlacementRequirement() const {
for (Boxes::const_iterator child_box_iterator = child_boxes().begin();
child_box_iterator != child_boxes().end(); ++child_box_iterator) {
Box* child_box = *child_box_iterator;
if (child_box->DoesFulfillEllipsisPlacementRequirement()) {
return true;
}
}
return false;
}
void InlineContainerBox::DoPreEllipsisPlacementProcessing() {
for (Boxes::const_iterator child_box_iterator = child_boxes().begin();
child_box_iterator != child_boxes().end(); ++child_box_iterator) {
(*child_box_iterator)->DoPreEllipsisPlacementProcessing();
}
}
void InlineContainerBox::DoPostEllipsisPlacementProcessing() {
for (Boxes::const_iterator child_box_iterator = child_boxes().begin();
child_box_iterator != child_boxes().end(); ++child_box_iterator) {
(*child_box_iterator)->DoPostEllipsisPlacementProcessing();
}
}
bool InlineContainerBox::TrySplitAtSecondBidiLevelRun() {
const int kInvalidLevel = -1;
int last_level = kInvalidLevel;
Boxes::const_iterator child_box_iterator = child_boxes().begin();
while (child_box_iterator != child_boxes().end()) {
Box* child_box = *child_box_iterator;
int current_level = child_box->GetBidiLevel().value_or(last_level);
// If the last level isn't equal to the current level, then check on whether
// or not the last level is kInvalidLevel. If it is, then no initial value
// has been set yet. Otherwise, the intersection of two bidi levels has been
// found where a split should occur.
if (last_level != current_level) {
if (last_level == kInvalidLevel) {
last_level = current_level;
} else {
break;
}
}
// Try to split the child box's internals.
if (child_box->TrySplitAtSecondBidiLevelRun()) {
child_box_iterator = InsertSplitSiblingOfDirectChild(child_box_iterator);
break;
}
++child_box_iterator;
}
// If the iterator reached the end, then no split was found.
if (child_box_iterator == child_boxes().end()) {
return false;
}
SplitAtIterator(child_box_iterator);
return true;
}
base::optional<int> InlineContainerBox::GetBidiLevel() const {
if (!child_boxes().empty()) {
return child_boxes().front()->GetBidiLevel();
}
return base::nullopt;
}
void InlineContainerBox::SetShouldCollapseLeadingWhiteSpace(
bool should_collapse_leading_white_space) {
if (should_collapse_leading_white_space_ !=
should_collapse_leading_white_space) {
should_collapse_leading_white_space_ = should_collapse_leading_white_space;
InvalidateUpdateSizeInputs();
}
}
void InlineContainerBox::SetShouldCollapseTrailingWhiteSpace(
bool should_collapse_trailing_white_space) {
if (should_collapse_trailing_white_space_ !=
should_collapse_trailing_white_space) {
should_collapse_trailing_white_space_ =
should_collapse_trailing_white_space;
InvalidateUpdateSizeInputs();
}
}
bool InlineContainerBox::HasLeadingWhiteSpace() const {
DCHECK_EQ(kInlineLevel, GetLevel());
DCHECK_EQ(width(), width()); // Width should not be NaN.
return has_leading_white_space_;
}
bool InlineContainerBox::HasTrailingWhiteSpace() const {
DCHECK_EQ(kInlineLevel, GetLevel());
DCHECK_EQ(width(), width()); // Width should not be NaN.
return has_trailing_white_space_;
}
bool InlineContainerBox::IsCollapsed() const {
DCHECK_EQ(kInlineLevel, GetLevel());
DCHECK_EQ(width(), width()); // Width should not be NaN.
return is_collapsed_;
}
bool InlineContainerBox::JustifiesLineExistence() const {
return justifies_line_existence_;
}
bool InlineContainerBox::HasTrailingLineBreak() const {
return !child_boxes().empty() && child_boxes().back()->HasTrailingLineBreak();
}
bool InlineContainerBox::AffectsBaselineInBlockFormattingContext() const {
NOTREACHED() << "Should only be called in a block formatting context.";
return true;
}
LayoutUnit InlineContainerBox::GetBaselineOffsetFromTopMarginEdge() const {
return baseline_offset_from_margin_box_top_;
}
bool InlineContainerBox::IsTransformable() const { return false; }
#ifdef COBALT_BOX_DUMP_ENABLED
void InlineContainerBox::DumpClassName(std::ostream* stream) const {
*stream << "InlineContainerBox ";
}
void InlineContainerBox::DumpProperties(std::ostream* stream) const {
ContainerBox::DumpProperties(stream);
*stream << std::boolalpha << "line_height=" << line_height_.toFloat() << " "
<< "inline_top_margin=" << inline_top_margin_.toFloat() << " "
<< "has_leading_white_space=" << has_leading_white_space_ << " "
<< "has_trailing_white_space=" << has_trailing_white_space_ << " "
<< "is_collapsed=" << is_collapsed_ << " "
<< "justifies_line_existence=" << justifies_line_existence_ << " "
<< std::noboolalpha;
}
#endif // COBALT_BOX_DUMP_ENABLED
void InlineContainerBox::DoPlaceEllipsisOrProcessPlacedEllipsis(
BaseDirection base_direction, LayoutUnit desired_offset,
bool* is_placement_requirement_met, bool* is_placed,
LayoutUnit* placed_offset) {
// If the ellipsis hasn't been previously placed, but the placement
// requirement is met and its desired offset comes before the content box's
// start edge, then place the ellipsis at its desired position. This can occur
// when the desired position falls between the start edge of the margin box
// and the start edge of its content box.
if (!*is_placed && *is_placement_requirement_met) {
LayoutUnit content_box_start_edge_offset =
GetContentBoxStartEdgeOffsetFromContainingBlock(base_direction);
if ((base_direction == kRightToLeftBaseDirection &&
desired_offset >= content_box_start_edge_offset) ||
(base_direction != kRightToLeftBaseDirection &&
desired_offset <= content_box_start_edge_offset)) {
*is_placed = true;
*placed_offset = desired_offset;
}
}
bool was_placed_before_children = *is_placed;
// Subtract the content box offset from the desired offset. This box's
// children will treat its content box left edge as the base ellipsis offset
// position, and the content box offset will be re-added after the ellipsis
// is placed. This allows its children to only focus on their offset from
// their containing block, and not worry about nested containing blocks.
LayoutUnit content_box_offset =
GetContentBoxLeftEdgeOffsetFromContainingBlock();
desired_offset -= content_box_offset;
// Walk each child box in base direction order attempting to place the
// ellipsis and update the box's ellipsis state. Even after the ellipsis is
// placed, subsequent boxes must still be processed, as their state my change
// as a result of having an ellipsis preceding them on the line.
if (base_direction == kRightToLeftBaseDirection) {
for (Boxes::const_reverse_iterator child_box_iterator =
child_boxes().rbegin();
child_box_iterator != child_boxes().rend(); ++child_box_iterator) {
Box* child_box = *child_box_iterator;
child_box->TryPlaceEllipsisOrProcessPlacedEllipsis(
base_direction, desired_offset, is_placement_requirement_met,
is_placed, placed_offset);
}
} else {
for (Boxes::const_iterator child_box_iterator = child_boxes().begin();
child_box_iterator != child_boxes().end(); ++child_box_iterator) {
Box* child_box = *child_box_iterator;
child_box->TryPlaceEllipsisOrProcessPlacedEllipsis(
base_direction, desired_offset, is_placement_requirement_met,
is_placed, placed_offset);
}
}
// If the ellipsis was not placed prior to processing the child boxes, then it
// is guaranteed that the placement location comes after the start edge of the
// content box. The content box's offset needs to be added back to the placed
// offset, so that the offset again references this box's containing block.
// Additionally, in the event that the ellipsis was not placed within a child
// box, it will now be placed.
if (!was_placed_before_children) {
// If the ellipsis hasn't been placed yet, then place the ellipsis at its
// desired position. This case can occur when the desired position falls
// between the end edge of the box's content and the end edge of the box's
// margin. In this case, |is_placement_requirement_met| does not need to be
// checked, as it is guaranteed that one of the child boxes met the
// requirement.
if (!(*is_placed)) {
*is_placed = true;
*placed_offset = desired_offset;
}
*placed_offset += content_box_offset;
}
}
WrapResult InlineContainerBox::TryWrapAtBefore(
WrapOpportunityPolicy wrap_opportunity_policy, bool is_line_requirement_met,
LayoutUnit available_width, bool should_collapse_trailing_white_space) {
// If there are no boxes within the inline container box, then there is no
// first box to try to wrap before. This box does not provide a wrappable
// point on its own. Additionally, if the line requirement has not been met
// before this box, then no wrap is available.
if (child_boxes().size() == 0 || !is_line_requirement_met) {
return kWrapResultNoWrap;
} else {
// Otherwise, attempt to wrap before the first child box.
return TryWrapAtIndex(0, kWrapAtPolicyBefore, wrap_opportunity_policy,
is_line_requirement_met, available_width,
should_collapse_trailing_white_space);
}
}
WrapResult InlineContainerBox::TryWrapAtLastOpportunityWithinWidth(
WrapOpportunityPolicy wrap_opportunity_policy,
bool is_line_existence_justified, LayoutUnit available_width,
bool should_collapse_trailing_white_space) {
DCHECK(GetMarginBoxWidth().GreaterThanOrNaN(available_width));
// Calculate the available width where the content begins. If the content
// does not begin within the available width, then the wrap can only occur
// before the inline container box.
available_width -= GetContentBoxLeftEdgeOffsetFromMarginBox();
if (available_width < LayoutUnit()) {
return TryWrapAtBefore(wrap_opportunity_policy, is_line_existence_justified,
available_width,
should_collapse_trailing_white_space);
}
// Determine the child box where the overflow occurs. If the overflow does not
// occur until after the end of the content, then the overflow index will be
// set to the number of child boxes.
size_t overflow_index = 0;
while (overflow_index < child_boxes().size()) {
Box* child_box = child_boxes()[overflow_index];
// Absolutely positioned boxes are not included in width calculations.
if (child_box->IsAbsolutelyPositioned()) {
continue;
}
LayoutUnit child_width = child_box->GetMarginBoxWidth();
if (child_width > available_width) {
break;
}
available_width -= child_width;
++overflow_index;
}
// If the overflow occurs before the line is justified, then no wrap is
// available.
if (!is_line_existence_justified &&
overflow_index < first_box_justifying_line_existence_index_) {
return kWrapResultNoWrap;
}
// If the overflow occurred within the content and not after, then attempt to
// wrap within the box that overflowed and return the result if the wrap is
// successful.
if (overflow_index < child_boxes().size()) {
WrapResult wrap_result =
TryWrapAtIndex(overflow_index, kWrapAtPolicyLastOpportunityWithinWidth,
wrap_opportunity_policy, is_line_existence_justified,
available_width, should_collapse_trailing_white_space);
if (wrap_result != kWrapResultNoWrap) {
return wrap_result;
}
}
// If no wrap was found within the box that overflowed, then attempt to wrap
// within an earlier child box.
return TryWrapAtLastOpportunityBeforeIndex(
overflow_index, wrap_opportunity_policy, is_line_existence_justified,
available_width, should_collapse_trailing_white_space);
}
WrapResult InlineContainerBox::TryWrapAtLastOpportunityBeforeIndex(
size_t index, WrapOpportunityPolicy wrap_opportunity_policy,
bool is_line_existence_justified, LayoutUnit available_width,
bool should_collapse_trailing_white_space) {
WrapResult wrap_result = kWrapResultNoWrap;
// If the line is already justified, then any child before the index is
// potentially wrappable. Otherwise, children preceding the first box that
// justifies the line's existence do not need to be checked, as they can
// never be wrappable.
size_t first_wrappable_index =
is_line_existence_justified ? 0
: first_box_justifying_line_existence_index_;
// Iterate backwards through the children attempting to wrap until a wrap is
// successful or the first wrappable index is reached.
while (wrap_result == kWrapResultNoWrap && index > first_wrappable_index) {
--index;
wrap_result =
TryWrapAtIndex(index, kWrapAtPolicyLastOpportunity,
wrap_opportunity_policy, is_line_existence_justified,
available_width, should_collapse_trailing_white_space);
}
return wrap_result;
}
WrapResult InlineContainerBox::TryWrapAtFirstOpportunity(
WrapOpportunityPolicy wrap_opportunity_policy,
bool is_line_existence_justified, LayoutUnit available_width,
bool should_collapse_trailing_white_space) {
WrapResult wrap_result = kWrapResultNoWrap;
// If the line is already justified, then any child is potentially wrappable.
// Otherwise, children preceding the first box that justifies the line's
// existence do not need to be checked, as they can never be wrappable.
size_t check_index = is_line_existence_justified
? 0
: first_box_justifying_line_existence_index_;
// Iterate forward through the children attempting to wrap until a wrap is
// successful or all of the children have been attempted.
for (; wrap_result == kWrapResultNoWrap && check_index < child_boxes().size();
++check_index) {
wrap_result =
TryWrapAtIndex(check_index, kWrapAtPolicyFirstOpportunity,
wrap_opportunity_policy, is_line_existence_justified,
available_width, should_collapse_trailing_white_space);
}
return wrap_result;
}
WrapResult InlineContainerBox::TryWrapAtIndex(
size_t wrap_index, WrapAtPolicy wrap_at_policy,
WrapOpportunityPolicy wrap_opportunity_policy,
bool is_line_existence_justified, LayoutUnit available_width,
bool should_collapse_trailing_white_space) {
Box* child_box = child_boxes()[wrap_index];
// Absolutely positioned boxes are not wrappable.
if (child_box->IsAbsolutelyPositioned()) {
return kWrapResultNoWrap;
}
// Check for whether the line is justified before this child. If it is not,
// then verify that the line is justified within this child. This function
// should not be called for unjustified indices.
bool is_line_existence_justified_before_index =
is_line_existence_justified ||
wrap_index > first_box_justifying_line_existence_index_;
DCHECK(is_line_existence_justified_before_index ||
wrap_index == first_box_justifying_line_existence_index_);
WrapResult wrap_result = child_box->TryWrapAt(
wrap_at_policy, wrap_opportunity_policy,
is_line_existence_justified_before_index, available_width,
should_collapse_trailing_white_space);
// If the no wrap was found, then simply return out. There's nothing to do.
if (wrap_result == kWrapResultNoWrap) {
return kWrapResultNoWrap;
// Otherwise, if the wrap is before the first child, then the wrap is
// happening before the full inline container box and no split is
// occurring.
// When breaks happen before the first or the last character of a box,
// the break occurs immediately before/after the box (at its margin edge)
// rather than breaking the box between its content edge and the content.
// https://www.w3.org/TR/css-text-3/#line-breaking
} else if (wrap_result == kWrapResultWrapBefore && wrap_index == 0) {
return kWrapResultWrapBefore;
// In all other cases, the inline container box is being split as a result
// of the wrap.
} else {
Boxes::const_iterator wrap_iterator =
child_boxes().begin() + static_cast<int>(wrap_index);
// If the child was split during its wrap, then the split sibling that was
// produced by the split needs to be added to the container's children.
if (wrap_result == kWrapResultSplitWrap) {
wrap_iterator = InsertSplitSiblingOfDirectChild(wrap_iterator);
}
SplitAtIterator(wrap_iterator);
return kWrapResultSplitWrap;
}
}
void InlineContainerBox::SplitAtIterator(
Boxes::const_iterator child_split_iterator) {
// TODO: When an inline box is split, margins, borders, and padding
// have no visual effect where the split occurs.
// https://www.w3.org/TR/CSS21/visuren.html#inline-formatting
// Move the children after the split into a new box.
scoped_refptr<InlineContainerBox> box_after_split(
new InlineContainerBox(css_computed_style_declaration(),
used_style_provider(), layout_stat_tracker()));
// Update the split sibling links.
box_after_split->split_sibling_ = split_sibling_;
split_sibling_ = box_after_split;
// Now move the children, starting at the iterator, from this container to the
// split sibling.
MoveDirectChildrenToSplitSibling(child_split_iterator);
#ifdef _DEBUG
// Make sure that the |UpdateContentSizeAndMargins| is called afterwards.
set_width(LayoutUnit());
set_height(LayoutUnit());
set_margin_left(LayoutUnit());
set_margin_top(LayoutUnit());
set_margin_right(LayoutUnit());
set_margin_bottom(LayoutUnit());
#endif // _DEBUG
}
} // namespace layout
} // namespace cobalt