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/*
* Copyright (C) 2013 Google 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:
*
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * 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.
* * Neither the name of Google Inc. nor the names of its
* contributors may be used to endorse or promote products derived from
* this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND 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 THE COPYRIGHT
* OWNER OR 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 "third_party/blink/renderer/core/layout/text_autosizer.h"
#include <algorithm>
#include <memory>
#include <utility>
#include "base/memory/ptr_util.h"
#include "third_party/blink/renderer/core/dom/document.h"
#include "third_party/blink/renderer/core/frame/local_frame.h"
#include "third_party/blink/renderer/core/frame/local_frame_view.h"
#include "third_party/blink/renderer/core/frame/settings.h"
#include "third_party/blink/renderer/core/frame/viewport_data.h"
#include "third_party/blink/renderer/core/frame/visual_viewport.h"
#include "third_party/blink/renderer/core/html/forms/html_text_area_element.h"
#include "third_party/blink/renderer/core/layout/layout_block.h"
#include "third_party/blink/renderer/core/layout/layout_inline.h"
#include "third_party/blink/renderer/core/layout/layout_list_item.h"
#include "third_party/blink/renderer/core/layout/layout_list_marker.h"
#include "third_party/blink/renderer/core/layout/layout_multi_column_flow_thread.h"
#include "third_party/blink/renderer/core/layout/layout_ruby_run.h"
#include "third_party/blink/renderer/core/layout/layout_table.h"
#include "third_party/blink/renderer/core/layout/layout_table_cell.h"
#include "third_party/blink/renderer/core/layout/layout_view.h"
#include "third_party/blink/renderer/core/layout/ng/list/layout_ng_list_item.h"
#include "third_party/blink/renderer/core/layout/ng/ng_block_node.h"
#include "third_party/blink/renderer/core/page/chrome_client.h"
#include "third_party/blink/renderer/core/page/page.h"
#include "third_party/blink/renderer/platform/geometry/int_rect.h"
namespace blink {
static LayoutObject* ParentElementLayoutObject(
const LayoutObject* layout_object) {
// At style recalc, the layoutObject's parent may not be attached,
// so we need to obtain this from the DOM tree.
const Node* node = layout_object->GetNode();
if (!node)
return nullptr;
// FIXME: This should be using LayoutTreeBuilderTraversal::parent().
if (Element* parent = node->parentElement())
return parent->GetLayoutObject();
return nullptr;
}
static bool IsNonTextAreaFormControl(const LayoutObject* layout_object) {
const Node* node = layout_object ? layout_object->GetNode() : nullptr;
if (!node || !node->IsElementNode())
return false;
const Element* element = ToElement(node);
return (element->IsFormControlElement() && !IsHTMLTextAreaElement(element));
}
static bool IsPotentialClusterRoot(const LayoutObject* layout_object) {
// "Potential cluster roots" are the smallest unit for which we can
// enable/disable text autosizing.
// - Must have children.
// An exception is made for LayoutView which should create a root to
// maintain consistency with documents that have no child nodes but may
// still have LayoutObject children.
// - Must not be inline, as different multipliers on one line looks terrible.
// Exceptions are inline-block and alike elements (inline-table,
// -webkit-inline-*), as they often contain entire multi-line columns of
// text.
// - Must not be normal list items, as items in the same list should look
// consistent, unless they are floating or position:absolute/fixed.
Node* node = layout_object->GeneratingNode();
if (node && !node->hasChildren() && !layout_object->IsLayoutView())
return false;
if (!layout_object->IsLayoutBlock())
return false;
if (layout_object->IsInline() &&
!layout_object->StyleRef().IsDisplayReplacedType())
return false;
if (layout_object->IsListItemIncludingNG())
return (layout_object->IsFloating() ||
layout_object->IsOutOfFlowPositioned());
return true;
}
static bool IsIndependentDescendant(const LayoutBlock* layout_object) {
DCHECK(IsPotentialClusterRoot(layout_object));
LayoutBlock* containing_block = layout_object->ContainingBlock();
return layout_object->IsLayoutView() || layout_object->IsFloating() ||
layout_object->IsOutOfFlowPositioned() ||
layout_object->IsTableCell() || layout_object->IsTableCaption() ||
layout_object->IsFlexibleBoxIncludingDeprecated() ||
(containing_block && containing_block->IsHorizontalWritingMode() !=
layout_object->IsHorizontalWritingMode()) ||
layout_object->StyleRef().IsDisplayReplacedType() ||
layout_object->IsTextArea() ||
layout_object->StyleRef().UserModify() != EUserModify::kReadOnly;
}
static bool BlockIsRowOfLinks(const LayoutBlock* block) {
// A "row of links" is a block for which:
// 1. It does not contain non-link text elements longer than 3 characters
// 2. It contains a minimum of 3 inline links and all links should
// have the same specified font size.
// 3. It should not contain <br> elements.
// 4. It should contain only inline elements unless they are containers,
// children of link elements or children of sub-containers.
int link_count = 0;
LayoutObject* layout_object = block->FirstChild();
float matching_font_size = -1;
while (layout_object) {
if (!IsPotentialClusterRoot(layout_object)) {
if (layout_object->IsText() &&
ToLayoutText(layout_object)->GetText().StripWhiteSpace().length() > 3)
return false;
if (!layout_object->IsInline() || layout_object->IsBR())
return false;
}
if (layout_object->StyleRef().IsLink()) {
link_count++;
if (matching_font_size < 0)
matching_font_size = layout_object->StyleRef().SpecifiedFontSize();
else if (matching_font_size !=
layout_object->StyleRef().SpecifiedFontSize())
return false;
// Skip traversing descendants of the link.
layout_object = layout_object->NextInPreOrderAfterChildren(block);
continue;
}
layout_object = layout_object->NextInPreOrder(block);
}
return (link_count >= 3);
}
static bool BlockHeightConstrained(const LayoutBlock* block) {
// FIXME: Propagate constrainedness down the tree, to avoid inefficiently
// walking back up from each box.
// FIXME: This code needs to take into account vertical writing modes.
// FIXME: Consider additional heuristics, such as ignoring fixed heights if
// the content is already overflowing before autosizing kicks in.
for (; block; block = block->ContainingBlock()) {
const ComputedStyle& style = block->StyleRef();
if (style.OverflowY() != EOverflow::kVisible
&& style.OverflowY() != EOverflow::kHidden)
return false;
if (style.Height().IsSpecified() || style.MaxHeight().IsSpecified() ||
block->IsOutOfFlowPositioned()) {
// Some sites (e.g. wikipedia) set their html and/or body elements to
// height:100%, without intending to constrain the height of the content
// within them.
return !block->IsDocumentElement() && !block->IsBody() &&
!block->IsLayoutView();
}
if (block->IsFloating())
return false;
}
return false;
}
static bool BlockOrImmediateChildrenAreFormControls(const LayoutBlock* block) {
if (IsNonTextAreaFormControl(block))
return true;
const LayoutObject* layout_object = block->FirstChild();
while (layout_object) {
if (IsNonTextAreaFormControl(layout_object))
return true;
layout_object = layout_object->NextSibling();
}
return false;
}
// Some blocks are not autosized even if their parent cluster wants them to.
static bool BlockSuppressesAutosizing(const LayoutBlock* block) {
if (BlockOrImmediateChildrenAreFormControls(block))
return true;
if (BlockIsRowOfLinks(block))
return true;
// Don't autosize block-level text that can't wrap (as it's likely to
// expand sideways and break the page's layout).
if (!block->StyleRef().AutoWrap())
return true;
if (BlockHeightConstrained(block))
return true;
return false;
}
static bool HasExplicitWidth(const LayoutBlock* block) {
// FIXME: This heuristic may need to be expanded to other ways a block can be
// wider or narrower than its parent containing block.
return block->Style() && block->StyleRef().Width().IsSpecified();
}
static LayoutObject* GetParent(const LayoutObject* object) {
LayoutObject* parent = nullptr;
// LayoutObject haven't added to layout tree yet
if (object->GetNode() && object->GetNode()->parentNode())
parent = object->GetNode()->parentNode()->GetLayoutObject();
return parent;
}
TextAutosizer::TextAutosizer(const Document* document)
: document_(document),
first_block_to_begin_layout_(nullptr),
#if DCHECK_IS_ON()
blocks_that_have_begun_layout_(),
#endif
cluster_stack_(),
fingerprint_mapper_(),
page_info_(),
update_page_info_deferred_(false) {
}
TextAutosizer::~TextAutosizer() = default;
void TextAutosizer::Record(LayoutBlock* block) {
if (!page_info_.setting_enabled_)
return;
#if DCHECK_IS_ON()
DCHECK(!blocks_that_have_begun_layout_.Contains(block));
#endif
if (!ClassifyBlock(block, INDEPENDENT | EXPLICIT_WIDTH)) {
// !everHadLayout() means the object hasn't layout yet
// which means this object is new added.
// We only deal with new added block here.
// If parent is new added, no need to check its children.
LayoutObject* parent = GetParent(block);
if (!block->EverHadLayout() && parent && parent->EverHadLayout())
MarkSuperclusterForConsistencyCheck(parent);
return;
}
if (Fingerprint fingerprint = ComputeFingerprint(block))
fingerprint_mapper_.AddTentativeClusterRoot(block, fingerprint);
if (!block->EverHadLayout())
MarkSuperclusterForConsistencyCheck(block);
}
void TextAutosizer::Record(LayoutText* text) {
if (!text || !ShouldHandleLayout())
return;
LayoutObject* parent = GetParent(text);
if (parent && parent->EverHadLayout())
MarkSuperclusterForConsistencyCheck(parent);
}
void TextAutosizer::Destroy(LayoutBlock* block) {
if (!page_info_.setting_enabled_ && !fingerprint_mapper_.HasFingerprints())
return;
#if DCHECK_IS_ON()
DCHECK(!blocks_that_have_begun_layout_.Contains(block));
#endif
if (fingerprint_mapper_.Remove(block) && first_block_to_begin_layout_) {
// LayoutBlock with a fingerprint was destroyed during layout.
// Clear the cluster stack and the supercluster map to avoid stale pointers.
// Speculative fix for http://crbug.com/369485.
first_block_to_begin_layout_ = nullptr;
cluster_stack_.clear();
}
}
TextAutosizer::BeginLayoutBehavior TextAutosizer::PrepareForLayout(
LayoutBlock* block) {
#if DCHECK_IS_ON()
blocks_that_have_begun_layout_.insert(block);
#endif
if (!first_block_to_begin_layout_) {
first_block_to_begin_layout_ = block;
PrepareClusterStack(block->Parent());
if (block->IsLayoutView())
CheckSuperclusterConsistency();
} else if (block == CurrentCluster()->root_) {
// Ignore beginLayout on the same block twice.
// This can happen with paginated overflow.
return kStopLayout;
}
return kContinueLayout;
}
void TextAutosizer::PrepareClusterStack(LayoutObject* layout_object) {
if (!layout_object)
return;
PrepareClusterStack(layout_object->Parent());
if (layout_object->IsLayoutBlock()) {
LayoutBlock* block = ToLayoutBlock(layout_object);
#if DCHECK_IS_ON()
blocks_that_have_begun_layout_.insert(block);
#endif
if (Cluster* cluster = MaybeCreateCluster(block))
cluster_stack_.push_back(base::WrapUnique(cluster));
}
}
void TextAutosizer::BeginLayout(LayoutBlock* block,
SubtreeLayoutScope* layouter) {
DCHECK(ShouldHandleLayout());
if (PrepareForLayout(block) == kStopLayout)
return;
// Skip ruby's inner blocks, because these blocks already are inflated.
if (block->IsRubyRun() || block->IsRubyBase() || block->IsRubyText())
return;
DCHECK(!cluster_stack_.IsEmpty() || block->IsLayoutView());
if (Cluster* cluster = MaybeCreateCluster(block))
cluster_stack_.push_back(base::WrapUnique(cluster));
DCHECK(!cluster_stack_.IsEmpty());
// Cells in auto-layout tables are handled separately by inflateAutoTable.
bool is_auto_table_cell =
block->IsTableCell() &&
!ToLayoutTableCell(block)->Table()->StyleRef().IsFixedTableLayout();
if (!is_auto_table_cell && !cluster_stack_.IsEmpty())
Inflate(block, layouter);
}
void TextAutosizer::InflateAutoTable(LayoutTable* table) {
DCHECK(table);
DCHECK(!table->StyleRef().IsFixedTableLayout());
DCHECK(table->ContainingBlock());
Cluster* cluster = CurrentCluster();
if (cluster->root_ != table)
return;
// Pre-inflate cells that have enough text so that their inflated preferred
// widths will be used for column sizing.
for (LayoutObject* section = table->FirstChild(); section;
section = section->NextSibling()) {
if (!section->IsTableSection())
continue;
for (LayoutTableRow* row = ToLayoutTableSection(section)->FirstRow(); row;
row = row->NextRow()) {
for (LayoutTableCell* cell = row->FirstCell(); cell;
cell = cell->NextCell()) {
if (!cell->NeedsLayout())
continue;
BeginLayout(cell, nullptr);
Inflate(cell, nullptr, kDescendToInnerBlocks);
EndLayout(cell);
}
}
}
}
void TextAutosizer::EndLayout(LayoutBlock* block) {
DCHECK(ShouldHandleLayout());
if (block == first_block_to_begin_layout_) {
first_block_to_begin_layout_ = nullptr;
cluster_stack_.clear();
styles_retained_during_layout_.clear();
#if DCHECK_IS_ON()
blocks_that_have_begun_layout_.clear();
#endif
// Tables can create two layout scopes for the same block so the isEmpty
// check below is needed to guard against endLayout being called twice.
} else if (!cluster_stack_.IsEmpty() && CurrentCluster()->root_ == block) {
cluster_stack_.pop_back();
}
}
float TextAutosizer::Inflate(LayoutObject* parent,
SubtreeLayoutScope* layouter,
InflateBehavior behavior,
float multiplier) {
Cluster* cluster = CurrentCluster();
bool has_text_child = false;
LayoutObject* child = nullptr;
if (parent->IsRuby()) {
// Skip layoutRubyRun which is inline-block.
// Inflate rubyRun's inner blocks.
LayoutObject* run = parent->SlowFirstChild();
if (run && run->IsRubyRun()) {
child = ToLayoutRubyRun(run)->FirstChild();
behavior = kDescendToInnerBlocks;
}
} else if (parent->IsLayoutBlock() &&
(parent->ChildrenInline() || behavior == kDescendToInnerBlocks)) {
child = ToLayoutBlock(parent)->FirstChild();
} else if (parent->IsLayoutInline()) {
child = ToLayoutInline(parent)->FirstChild();
}
while (child) {
if (child->IsText()) {
has_text_child = true;
// We only calculate this multiplier on-demand to ensure the parent block
// of this text has entered layout.
if (!multiplier)
multiplier =
cluster->flags_ & SUPPRESSING ? 1.0f : ClusterMultiplier(cluster);
ApplyMultiplier(child, multiplier, layouter);
if (behavior == kDescendToInnerBlocks) {
// The ancestor nodes might be inline-blocks. We should
// setPreferredLogicalWidthsDirty for ancestor nodes here.
child->SetPreferredLogicalWidthsDirty();
} else if (parent->IsLayoutInline()) {
// FIXME: Investigate why MarkOnlyThis is sufficient.
child->SetPreferredLogicalWidthsDirty(kMarkOnlyThis);
}
} else if (child->IsLayoutInline()) {
multiplier = Inflate(child, layouter, behavior, multiplier);
// If this LayoutInline is an anonymous inline that has multiplied
// children, apply the multiplifer to the parent too. We compute
// ::first-line style from the style of the parent block.
if (multiplier && child->IsAnonymous())
has_text_child = true;
} else if (child->IsLayoutBlock() && behavior == kDescendToInnerBlocks &&
!ClassifyBlock(child,
INDEPENDENT | EXPLICIT_WIDTH | SUPPRESSING)) {
multiplier = Inflate(child, layouter, behavior, multiplier);
}
child = child->NextSibling();
}
if (has_text_child) {
ApplyMultiplier(parent, multiplier,
layouter); // Parent handles line spacing.
} else if (!parent->IsListItemIncludingNG()) {
// For consistency, a block with no immediate text child should always have
// a multiplier of 1.
ApplyMultiplier(parent, 1, layouter);
}
if (parent->IsListItemIncludingNG()) {
float multiplier = ClusterMultiplier(cluster);
ApplyMultiplier(parent, multiplier, layouter);
// The list item has to be treated special because we can have a tree such
// that you have a list item for a form inside it. The list marker then ends
// up inside the form and when we try to get the clusterMultiplier we have
// the wrong cluster root to work from and get the wrong value.
LayoutObject* marker = nullptr;
if (parent->IsListItem())
marker = ToLayoutListItem(parent)->Marker();
else if (parent->IsLayoutNGListItem())
marker = ToLayoutNGListItem(parent)->Marker();
// A LayoutNGListMarker has a text child that needs its font multiplier
// updated. Just mark the entire subtree, to make sure we get to it.
for (LayoutObject* walker = marker; walker;
walker = walker->NextInPreOrder(marker)) {
ApplyMultiplier(walker, multiplier, layouter);
walker->SetPreferredLogicalWidthsDirty(kMarkOnlyThis);
}
}
if (page_info_.has_autosized_)
UseCounter::Count(*document_, WebFeature::kTextAutosizing);
return multiplier;
}
bool TextAutosizer::ShouldHandleLayout() const {
return page_info_.setting_enabled_ && page_info_.page_needs_autosizing_ &&
!update_page_info_deferred_;
}
bool TextAutosizer::PageNeedsAutosizing() const {
return page_info_.page_needs_autosizing_;
}
void TextAutosizer::MarkSuperclusterForConsistencyCheck(LayoutObject* object) {
if (!object || !ShouldHandleLayout())
return;
Supercluster* last_supercluster = nullptr;
LayoutBlock* block = nullptr;
while (object) {
if (object->IsLayoutBlock()) {
block = ToLayoutBlock(object);
if (block->IsTableCell() ||
ClassifyBlock(block, INDEPENDENT | EXPLICIT_WIDTH)) {
// If supercluster hasn't been created yet, create one.
bool is_new_entry = false;
Supercluster* supercluster =
fingerprint_mapper_.CreateSuperclusterIfNeeded(block, is_new_entry);
if (supercluster && supercluster->inherit_parent_multiplier_ ==
kDontInheritMultiplier) {
if (supercluster->has_enough_text_to_autosize_ == kNotEnoughText) {
fingerprint_mapper_.GetPotentiallyInconsistentSuperclusters()
.insert(supercluster);
}
return;
}
if (supercluster &&
(is_new_entry ||
supercluster->has_enough_text_to_autosize_ == kNotEnoughText))
last_supercluster = supercluster;
}
}
object = GetParent(object);
}
// If we didn't add any supercluster, we should add one.
if (last_supercluster) {
fingerprint_mapper_.GetPotentiallyInconsistentSuperclusters().insert(
last_supercluster);
}
}
void TextAutosizer::UpdatePageInfoInAllFrames() {
DCHECK(!document_->GetFrame() || document_->GetFrame()->IsMainFrame());
for (Frame* frame = document_->GetFrame(); frame;
frame = frame->Tree().TraverseNext()) {
if (!frame->IsLocalFrame())
continue;
Document* document = ToLocalFrame(frame)->GetDocument();
// If document is being detached, skip updatePageInfo.
if (!document || !document->IsActive())
continue;
if (TextAutosizer* text_autosizer = document->GetTextAutosizer())
text_autosizer->UpdatePageInfo();
}
}
void TextAutosizer::UpdatePageInfo() {
if (update_page_info_deferred_ || !document_->GetPage() ||
!document_->GetSettings())
return;
PageInfo previous_page_info(page_info_);
page_info_.setting_enabled_ =
document_->GetSettings()->TextAutosizingEnabled();
if (!page_info_.setting_enabled_ || document_->Printing()) {
page_info_.page_needs_autosizing_ = false;
} else {
auto* layout_view = document_->GetLayoutView();
bool horizontal_writing_mode =
IsHorizontalWritingMode(layout_view->StyleRef().GetWritingMode());
// FIXME: With out-of-process iframes, the top frame can be remote and
// doesn't have sizing information. Just return if this is the case.
Frame& frame = document_->GetFrame()->Tree().Top();
if (frame.IsRemoteFrame())
return;
LocalFrame& main_frame = ToLocalFrame(frame);
IntSize frame_size =
document_->GetSettings()->TextAutosizingWindowSizeOverride();
if (frame_size.IsEmpty())
frame_size = WindowSize();
page_info_.frame_width_ =
horizontal_writing_mode ? frame_size.Width() : frame_size.Height();
IntSize layout_size = main_frame.View()->GetLayoutSize();
page_info_.layout_width_ =
horizontal_writing_mode ? layout_size.Width() : layout_size.Height();
// TODO(pdr): Accessibility should be moved out of the text autosizer. See:
// crbug.com/645717.
page_info_.accessibility_font_scale_factor_ =
document_->GetSettings()->GetAccessibilityFontScaleFactor();
// If the page has a meta viewport or @viewport, don't apply the device
// scale adjustment.
if (!main_frame.GetDocument()
->GetViewportData()
.GetViewportDescription()
.IsSpecifiedByAuthor()) {
page_info_.device_scale_adjustment_ =
document_->GetSettings()->GetDeviceScaleAdjustment();
} else {
page_info_.device_scale_adjustment_ = 1.0f;
}
// TODO(pdr): pageNeedsAutosizing should take into account whether
// text-size-adjust is used anywhere on the page because that also needs to
// trigger autosizing. See: crbug.com/646237.
page_info_.page_needs_autosizing_ =
!!page_info_.frame_width_ &&
(page_info_.accessibility_font_scale_factor_ *
page_info_.device_scale_adjustment_ *
(static_cast<float>(page_info_.layout_width_) /
page_info_.frame_width_) >
1.0f);
}
if (page_info_.page_needs_autosizing_) {
// If page info has changed, multipliers may have changed. Force a layout to
// recompute them.
if (page_info_.frame_width_ != previous_page_info.frame_width_ ||
page_info_.layout_width_ != previous_page_info.layout_width_ ||
page_info_.accessibility_font_scale_factor_ !=
previous_page_info.accessibility_font_scale_factor_ ||
page_info_.device_scale_adjustment_ !=
previous_page_info.device_scale_adjustment_ ||
page_info_.setting_enabled_ != previous_page_info.setting_enabled_)
SetAllTextNeedsLayout();
} else if (previous_page_info.has_autosized_) {
// If we are no longer autosizing the page, we won't do anything during the
// next layout. Set all the multipliers back to 1 now.
ResetMultipliers();
page_info_.has_autosized_ = false;
}
}
IntSize TextAutosizer::WindowSize() const {
Page* page = document_->GetPage();
DCHECK(page);
return page->GetVisualViewport().Size();
}
void TextAutosizer::ResetMultipliers() {
LayoutObject* layout_object = document_->GetLayoutView();
while (layout_object) {
if (const ComputedStyle* style = layout_object->Style()) {
if (style->TextAutosizingMultiplier() != 1)
ApplyMultiplier(layout_object, 1, nullptr, kLayoutNeeded);
}
layout_object = layout_object->NextInPreOrder();
}
}
void TextAutosizer::SetAllTextNeedsLayout(LayoutBlock* container) {
if (!container)
container = document_->GetLayoutView();
LayoutObject* object = container;
while (object) {
if (!object->EverHadLayout()) {
// Object is new added node, so no need to deal with its children
object = object->NextInPreOrderAfterChildren(container);
} else {
if (object->IsText()) {
object->SetNeedsLayoutAndFullPaintInvalidation(
layout_invalidation_reason::kTextAutosizing);
}
object = object->NextInPreOrder(container);
}
}
}
TextAutosizer::BlockFlags TextAutosizer::ClassifyBlock(
const LayoutObject* layout_object,
BlockFlags mask) const {
if (!layout_object->IsLayoutBlock())
return 0;
const LayoutBlock* block = ToLayoutBlock(layout_object);
BlockFlags flags = 0;
if (IsPotentialClusterRoot(block)) {
if (mask & POTENTIAL_ROOT)
flags |= POTENTIAL_ROOT;
LayoutMultiColumnFlowThread* flow_thread = nullptr;
if (block->IsLayoutBlockFlow())
flow_thread = ToLayoutBlockFlow(block)->MultiColumnFlowThread();
if ((mask & INDEPENDENT) &&
(IsIndependentDescendant(block) || block->IsTable() ||
(flow_thread && flow_thread->ColumnCount() > 1)))
flags |= INDEPENDENT;
if ((mask & EXPLICIT_WIDTH) && HasExplicitWidth(block))
flags |= EXPLICIT_WIDTH;
if ((mask & SUPPRESSING) && BlockSuppressesAutosizing(block))
flags |= SUPPRESSING;
}
return flags;
}
bool TextAutosizer::ClusterWouldHaveEnoughTextToAutosize(
const LayoutBlock* root,
const LayoutBlock* width_provider) {
Cluster hypothetical_cluster(root, ClassifyBlock(root), nullptr);
return ClusterHasEnoughTextToAutosize(&hypothetical_cluster, width_provider);
}
bool TextAutosizer::ClusterHasEnoughTextToAutosize(
Cluster* cluster,
const LayoutBlock* width_provider) {
if (cluster->has_enough_text_to_autosize_ != kUnknownAmountOfText)
return cluster->has_enough_text_to_autosize_ == kHasEnoughText;
const LayoutBlock* root = cluster->root_;
if (!width_provider)
width_provider = ClusterWidthProvider(root);
// TextAreas and user-modifiable areas get a free pass to autosize regardless
// of text content.
if (root->IsTextArea() || (root->Style() && root->StyleRef().UserModify() !=
EUserModify::kReadOnly)) {
cluster->has_enough_text_to_autosize_ = kHasEnoughText;
return true;
}
if (cluster->flags_ & SUPPRESSING) {
cluster->has_enough_text_to_autosize_ = kNotEnoughText;
return false;
}
// 4 lines of text is considered enough to autosize.
float minimum_text_length_to_autosize = WidthFromBlock(width_provider) * 4;
if (LocalFrameView* view = document_->View()) {
minimum_text_length_to_autosize =
document_->GetPage()
->GetChromeClient()
.ViewportToScreen(IntRect(0, 0, minimum_text_length_to_autosize, 0),
view)
.Width();
}
float length = 0;
LayoutObject* descendant = root->FirstChild();
while (descendant) {
if (descendant->IsLayoutBlock()) {
if (ClassifyBlock(descendant, INDEPENDENT | SUPPRESSING)) {
descendant = descendant->NextInPreOrderAfterChildren(root);
continue;
}
} else if (descendant->IsText()) {
// Note: Using text().stripWhiteSpace().length() instead of
// resolvedTextLength() because the lineboxes will not be built until
// layout. These values can be different.
// Note: This is an approximation assuming each character is 1em wide.
length += ToLayoutText(descendant)->GetText().StripWhiteSpace().length() *
descendant->StyleRef().SpecifiedFontSize();
if (length >= minimum_text_length_to_autosize) {
cluster->has_enough_text_to_autosize_ = kHasEnoughText;
return true;
}
}
descendant = descendant->NextInPreOrder(root);
}
cluster->has_enough_text_to_autosize_ = kNotEnoughText;
return false;
}
TextAutosizer::Fingerprint TextAutosizer::GetFingerprint(
LayoutObject* layout_object) {
Fingerprint result = fingerprint_mapper_.Get(layout_object);
if (!result) {
result = ComputeFingerprint(layout_object);
fingerprint_mapper_.Add(layout_object, result);
}
return result;
}
TextAutosizer::Fingerprint TextAutosizer::ComputeFingerprint(
const LayoutObject* layout_object) {
Node* node = layout_object->GeneratingNode();
if (!node || !node->IsElementNode())
return 0;
FingerprintSourceData data;
if (LayoutObject* parent = ParentElementLayoutObject(layout_object))
data.parent_hash_ = GetFingerprint(parent);
data.qualified_name_hash_ =
QualifiedNameHash::GetHash(ToElement(node)->TagQName());
if (const ComputedStyle* style = layout_object->Style()) {
data.packed_style_properties_ = static_cast<unsigned>(style->Direction());
data.packed_style_properties_ |=
(static_cast<unsigned>(style->GetPosition()) << 1);
data.packed_style_properties_ |=
(static_cast<unsigned>(style->Floating()) << 4);
data.packed_style_properties_ |=
(static_cast<unsigned>(style->Display()) << 7);
data.packed_style_properties_ |= (style->Width().GetType() << 12);
// packedStyleProperties effectively using 16 bits now.
// consider for adding: writing mode, padding.
data.width_ = style->Width().GetFloatValue();
}
// Use nodeIndex as a rough approximation of column number
// (it's too early to call LayoutTableCell::col).
// FIXME: account for colspan
if (layout_object->IsTableCell())
data.column_ = layout_object->GetNode()->NodeIndex();
return StringHasher::ComputeHash<UChar>(
static_cast<const UChar*>(static_cast<const void*>(&data)),
sizeof data / sizeof(UChar));
}
TextAutosizer::Cluster* TextAutosizer::MaybeCreateCluster(LayoutBlock* block) {
BlockFlags flags = ClassifyBlock(block);
if (!(flags & POTENTIAL_ROOT))
return nullptr;
Cluster* parent_cluster =
cluster_stack_.IsEmpty() ? nullptr : CurrentCluster();
DCHECK(parent_cluster || block->IsLayoutView());
// If a non-independent block would not alter the SUPPRESSING flag, it doesn't
// need to be a cluster.
bool parent_suppresses =
parent_cluster && (parent_cluster->flags_ & SUPPRESSING);
if (!(flags & INDEPENDENT) && !(flags & EXPLICIT_WIDTH) &&
!!(flags & SUPPRESSING) == parent_suppresses)
return nullptr;
bool is_new_entry = false;
Cluster* cluster = new Cluster(
block, flags, parent_cluster,
fingerprint_mapper_.CreateSuperclusterIfNeeded(block, is_new_entry));
return cluster;
}
TextAutosizer::Supercluster*
TextAutosizer::FingerprintMapper::CreateSuperclusterIfNeeded(
LayoutBlock* block,
bool& is_new_entry) {
Fingerprint fingerprint = Get(block);
if (!fingerprint)
return nullptr;
BlockSet* roots = GetTentativeClusterRoots(fingerprint);
if (!roots || roots->size() < 2 || !roots->Contains(block))
return nullptr;
SuperclusterMap::AddResult add_result =
superclusters_.insert(fingerprint, std::unique_ptr<Supercluster>());
is_new_entry = add_result.is_new_entry;
if (!add_result.is_new_entry)
return add_result.stored_value->value.get();
Supercluster* supercluster = new Supercluster(roots);
add_result.stored_value->value = base::WrapUnique(supercluster);
return supercluster;
}
float TextAutosizer::ClusterMultiplier(Cluster* cluster) {
if (cluster->multiplier_)
return cluster->multiplier_;
// FIXME: why does isWiderOrNarrowerDescendant crash on independent clusters?
if (!(cluster->flags_ & INDEPENDENT) && IsWiderOrNarrowerDescendant(cluster))
cluster->flags_ |= WIDER_OR_NARROWER;
if (cluster->flags_ & (INDEPENDENT | WIDER_OR_NARROWER)) {
if (cluster->supercluster_) {
cluster->multiplier_ = SuperclusterMultiplier(cluster);
cluster->supercluster_->inherit_parent_multiplier_ =
kDontInheritMultiplier;
} else if (ClusterHasEnoughTextToAutosize(cluster))
cluster->multiplier_ =
MultiplierFromBlock(ClusterWidthProvider(cluster->root_));
else
cluster->multiplier_ = 1.0f;
} else {
cluster->multiplier_ =
cluster->parent_ ? ClusterMultiplier(cluster->parent_) : 1.0f;
if (cluster->supercluster_)
cluster->supercluster_->inherit_parent_multiplier_ = kInheritMultiplier;
}
DCHECK(cluster->multiplier_);
return cluster->multiplier_;
}
bool TextAutosizer::SuperclusterHasEnoughTextToAutosize(
Supercluster* supercluster,
const LayoutBlock* width_provider,
const bool skip_layouted_nodes) {
if (supercluster->has_enough_text_to_autosize_ != kUnknownAmountOfText)
return supercluster->has_enough_text_to_autosize_ == kHasEnoughText;
for (auto* root : *supercluster->roots_) {
if (skip_layouted_nodes && !root->NormalChildNeedsLayout())
continue;
if (ClusterWouldHaveEnoughTextToAutosize(root, width_provider)) {
supercluster->has_enough_text_to_autosize_ = kHasEnoughText;
return true;
}
}
supercluster->has_enough_text_to_autosize_ = kNotEnoughText;
return false;
}
float TextAutosizer::SuperclusterMultiplier(Cluster* cluster) {
Supercluster* supercluster = cluster->supercluster_;
if (!supercluster->multiplier_) {
const LayoutBlock* width_provider =
MaxClusterWidthProvider(cluster->supercluster_, cluster->root_);
CHECK(width_provider);
supercluster->multiplier_ =
SuperclusterHasEnoughTextToAutosize(supercluster, width_provider, false)
? MultiplierFromBlock(width_provider)
: 1.0f;
}
DCHECK(supercluster->multiplier_);
return supercluster->multiplier_;
}
const LayoutBlock* TextAutosizer::ClusterWidthProvider(
const LayoutBlock* root) const {
if (root->IsTable() || root->IsTableCell())
return root;
return DeepestBlockContainingAllText(root);
}
const LayoutBlock* TextAutosizer::MaxClusterWidthProvider(
Supercluster* supercluster,
const LayoutBlock* current_root) const {
const LayoutBlock* result = nullptr;
if (current_root)
result = ClusterWidthProvider(current_root);
float max_width = 0;
if (result)
max_width = WidthFromBlock(result);
const BlockSet* roots = supercluster->roots_;
for (const auto* root : *roots) {
const LayoutBlock* width_provider = ClusterWidthProvider(root);
if (width_provider->NeedsLayout())
continue;
float width = WidthFromBlock(width_provider);
if (width > max_width) {
max_width = width;
result = width_provider;
}
}
return result;
}
float TextAutosizer::WidthFromBlock(const LayoutBlock* block) const {
CHECK(block);
CHECK(block->Style());
if (!(block->IsTable() || block->IsTableCell() ||
block->IsListItemIncludingNG()))
return block->ContentLogicalWidth().ToFloat();
if (!block->ContainingBlock())
return 0;
// Tables may be inflated before computing their preferred widths. Try several
// methods to obtain a width, and fall back on a containing block's width.
for (; block; block = block->ContainingBlock()) {
float width;
Length specified_width =
block->IsTableCell()
? ToLayoutTableCell(block)->StyleOrColLogicalWidth()
: block->StyleRef().LogicalWidth();
if (specified_width.IsFixed()) {
if ((width = specified_width.Value()) > 0)
return width;
}
if (specified_width.IsPercentOrCalc()) {
if (float container_width =
block->ContainingBlock()->ContentLogicalWidth().ToFloat()) {
if ((width = FloatValueForLength(specified_width, container_width)) > 0)
return width;
}
}
if ((width = block->ContentLogicalWidth().ToFloat()) > 0)
return width;
}
return 0;
}
float TextAutosizer::MultiplierFromBlock(const LayoutBlock* block) {
// If block->needsLayout() is false, it does not need to be in
// m_blocksThatHaveBegunLayout. This can happen during layout of a positioned
// object if the cluster's DBCAT is deeper than the positioned object's
// containing block, and wasn't marked as needing layout.
#if DCHECK_IS_ON()
DCHECK(blocks_that_have_begun_layout_.Contains(block) ||
!block->NeedsLayout());
#endif
// Block width, in CSS pixels.
float block_width = WidthFromBlock(block);
float layout_width =
std::min(block_width, static_cast<float>(page_info_.layout_width_));
float multiplier =
page_info_.frame_width_ ? layout_width / page_info_.frame_width_ : 1.0f;
multiplier *= page_info_.accessibility_font_scale_factor_ *
page_info_.device_scale_adjustment_;
return std::max(multiplier, 1.0f);
}
const LayoutBlock* TextAutosizer::DeepestBlockContainingAllText(
Cluster* cluster) {
if (!cluster->deepest_block_containing_all_text_)
cluster->deepest_block_containing_all_text_ =
DeepestBlockContainingAllText(cluster->root_);
return cluster->deepest_block_containing_all_text_;
}
// FIXME: Refactor this to look more like TextAutosizer::deepestCommonAncestor.
const LayoutBlock* TextAutosizer::DeepestBlockContainingAllText(
const LayoutBlock* root) const {
// To avoid font-size shaking caused by the change of LayoutView's
// DeepestBlockContainingAllText.
if (root->IsLayoutView())
return root;
size_t first_depth = 0;
const LayoutObject* first_text_leaf = FindTextLeaf(root, first_depth, kFirst);
if (!first_text_leaf)
return root;
size_t last_depth = 0;
const LayoutObject* last_text_leaf = FindTextLeaf(root, last_depth, kLast);
DCHECK(last_text_leaf);
// Equalize the depths if necessary. Only one of the while loops below will
// get executed.
const LayoutObject* first_node = first_text_leaf;
const LayoutObject* last_node = last_text_leaf;
while (first_depth > last_depth) {
first_node = first_node->Parent();
--first_depth;
}
while (last_depth > first_depth) {
last_node = last_node->Parent();
--last_depth;
}
// Go up from both nodes until the parent is the same. Both pointers will
// point to the LCA then.
while (first_node != last_node) {
first_node = first_node->Parent();
last_node = last_node->Parent();
}
if (first_node->IsLayoutBlock())
return ToLayoutBlock(first_node);
// containingBlock() should never leave the cluster, since it only skips
// ancestors when finding the container of position:absolute/fixed blocks, and
// those cannot exist between a cluster and its text node's lowest common
// ancestor as isAutosizingCluster would have made them into their own
// independent cluster.
const LayoutBlock* containing_block = first_node->ContainingBlock();
if (!containing_block)
return root;
DCHECK(containing_block->IsDescendantOf(root));
return containing_block;
}
const LayoutObject* TextAutosizer::FindTextLeaf(
const LayoutObject* parent,
size_t& depth,
TextLeafSearch first_or_last) const {
// List items are treated as text due to the marker.
if (parent->IsListItemIncludingNG())
return parent;
if (parent->IsText())
return parent;
++depth;
const LayoutObject* child = (first_or_last == kFirst)
? parent->SlowFirstChild()
: parent->SlowLastChild();
while (child) {
// Note: At this point clusters may not have been created for these blocks
// so we cannot rely on m_clusters. Instead, we use a best-guess about
// whether the block will become a cluster.
if (!ClassifyBlock(child, INDEPENDENT)) {
if (const LayoutObject* leaf = FindTextLeaf(child, depth, first_or_last))
return leaf;
}
child = (first_or_last == kFirst) ? child->NextSibling()
: child->PreviousSibling();
}
--depth;
return nullptr;
}
void TextAutosizer::ApplyMultiplier(LayoutObject* layout_object,
float multiplier,
SubtreeLayoutScope* layouter,
RelayoutBehavior relayout_behavior) {
DCHECK(layout_object);
const ComputedStyle& current_style = layout_object->StyleRef();
if (!current_style.GetTextSizeAdjust().IsAuto()) {
// The accessibility font scale factor is applied by the autosizer so we
// need to apply that scale factor on top of the text-size-adjust
// multiplier. Only apply the accessibility factor if the autosizer has
// determined a multiplier should be applied so that text-size-adjust:none
// does not cause a multiplier to be applied when it wouldn't be otherwise.
bool should_apply_accessibility_font_scale_factor = multiplier > 1;
multiplier = current_style.GetTextSizeAdjust().Multiplier();
if (should_apply_accessibility_font_scale_factor)
multiplier *= page_info_.accessibility_font_scale_factor_;
} else if (multiplier < 1) {
// Unlike text-size-adjust, the text autosizer should only inflate fonts.
multiplier = 1;
}
if (current_style.TextAutosizingMultiplier() == multiplier)
return;
scoped_refptr<ComputedStyle> style = ComputedStyle::Clone(current_style);
style->SetTextAutosizingMultiplier(multiplier);
switch (relayout_behavior) {
case kAlreadyInLayout:
// Don't free currentStyle until the end of the layout pass. This allows
// other parts of the system to safely hold raw ComputedStyle* pointers
// during layout, e.g. BreakingContext::m_currentStyle.
styles_retained_during_layout_.push_back(&current_style);
layout_object->SetStyleInternal(std::move(style));
if (layout_object->IsText())
ToLayoutText(layout_object)->AutosizingMultiplerChanged();
DCHECK(!layouter || layout_object->IsDescendantOf(&layouter->Root()));
layout_object->SetNeedsLayoutAndFullPaintInvalidation(
layout_invalidation_reason::kTextAutosizing, kMarkContainerChain,
layouter);
layout_object->MarkContainerNeedsCollectInlines();
break;
case kLayoutNeeded:
DCHECK(!layouter);
layout_object->SetStyle(std::move(style));
break;
}
if (multiplier != 1)
page_info_.has_autosized_ = true;
layout_object->ClearBaseComputedStyle();
}
bool TextAutosizer::IsWiderOrNarrowerDescendant(Cluster* cluster) {
// FIXME: Why do we return true when hasExplicitWidth returns false??
if (!cluster->parent_ || !HasExplicitWidth(cluster->root_))
return true;
const LayoutBlock* parent_deepest_block_containing_all_text =
DeepestBlockContainingAllText(cluster->parent_);
#if DCHECK_IS_ON()
DCHECK(blocks_that_have_begun_layout_.Contains(cluster->root_));
DCHECK(blocks_that_have_begun_layout_.Contains(
parent_deepest_block_containing_all_text));
#endif
float content_width =
DeepestBlockContainingAllText(cluster)->ContentLogicalWidth().ToFloat();
float cluster_text_width =
parent_deepest_block_containing_all_text->ContentLogicalWidth().ToFloat();
// Clusters with a root that is wider than the deepestBlockContainingAllText
// of their parent autosize independently of their parent.
if (content_width > cluster_text_width)
return true;
// Clusters with a root that is significantly narrower than the
// deepestBlockContainingAllText of their parent autosize independently of
// their parent.
static float narrow_width_difference = 200;
if (cluster_text_width - content_width > narrow_width_difference)
return true;
return false;
}
TextAutosizer::Cluster* TextAutosizer::CurrentCluster() const {
SECURITY_DCHECK(!cluster_stack_.IsEmpty());
return cluster_stack_.back().get();
}
TextAutosizer::Cluster::Cluster(const LayoutBlock* root,
BlockFlags flags,
Cluster* parent,
Supercluster* supercluster)
: root_(root),
flags_(flags),
deepest_block_containing_all_text_(nullptr),
parent_(parent),
multiplier_(0),
has_enough_text_to_autosize_(kUnknownAmountOfText),
supercluster_(supercluster),
has_table_ancestor_(root->IsTableCell() ||
(parent_ && parent_->has_table_ancestor_)) {}
#if DCHECK_IS_ON()
void TextAutosizer::FingerprintMapper::AssertMapsAreConsistent() {
// For each fingerprint -> block mapping in m_blocksForFingerprint we should
// have an associated map from block -> fingerprint in m_fingerprints.
ReverseFingerprintMap::iterator end = blocks_for_fingerprint_.end();
for (ReverseFingerprintMap::iterator fingerprint_it =
blocks_for_fingerprint_.begin();
fingerprint_it != end; ++fingerprint_it) {
Fingerprint fingerprint = fingerprint_it->key;
BlockSet* blocks = fingerprint_it->value.get();
for (BlockSet::iterator block_it = blocks->begin();
block_it != blocks->end(); ++block_it) {
const LayoutBlock* block = (*block_it);
DCHECK_EQ(fingerprints_.at(block), fingerprint);
}
}
}
#endif
void TextAutosizer::FingerprintMapper::Add(LayoutObject* layout_object,
Fingerprint fingerprint) {
Remove(layout_object);
fingerprints_.Set(layout_object, fingerprint);
#if DCHECK_IS_ON()
AssertMapsAreConsistent();
#endif
}
void TextAutosizer::FingerprintMapper::AddTentativeClusterRoot(
LayoutBlock* block,
Fingerprint fingerprint) {
Add(block, fingerprint);
ReverseFingerprintMap::AddResult add_result =
blocks_for_fingerprint_.insert(fingerprint, std::unique_ptr<BlockSet>());
if (add_result.is_new_entry)
add_result.stored_value->value = std::make_unique<BlockSet>();
add_result.stored_value->value->insert(block);
#if DCHECK_IS_ON()
AssertMapsAreConsistent();
#endif
}
bool TextAutosizer::FingerprintMapper::Remove(LayoutObject* layout_object) {
Fingerprint fingerprint = fingerprints_.Take(layout_object);
if (!fingerprint || !layout_object->IsLayoutBlock())
return false;
ReverseFingerprintMap::iterator blocks_iter =
blocks_for_fingerprint_.find(fingerprint);
if (blocks_iter == blocks_for_fingerprint_.end())
return false;
BlockSet& blocks = *blocks_iter->value;
blocks.erase(ToLayoutBlock(layout_object));
if (blocks.IsEmpty()) {
blocks_for_fingerprint_.erase(blocks_iter);
SuperclusterMap::iterator supercluster_iter =
superclusters_.find(fingerprint);
if (supercluster_iter != superclusters_.end()) {
Supercluster* supercluster = supercluster_iter->value.get();
potentially_inconsistent_superclusters_.erase(supercluster);
superclusters_.erase(supercluster_iter);
}
}
#if DCHECK_IS_ON()
AssertMapsAreConsistent();
#endif
return true;
}
TextAutosizer::Fingerprint TextAutosizer::FingerprintMapper::Get(
const LayoutObject* layout_object) {
return fingerprints_.at(layout_object);
}
TextAutosizer::BlockSet*
TextAutosizer::FingerprintMapper::GetTentativeClusterRoots(
Fingerprint fingerprint) {
return blocks_for_fingerprint_.at(fingerprint);
}
TextAutosizer::LayoutScope::LayoutScope(LayoutBlock* block,
SubtreeLayoutScope* layouter)
: text_autosizer_(block->GetDocument().GetTextAutosizer()), block_(block) {
if (!text_autosizer_)
return;
if (text_autosizer_->ShouldHandleLayout())
text_autosizer_->BeginLayout(block_, layouter);
else
text_autosizer_ = nullptr;
}
TextAutosizer::LayoutScope::~LayoutScope() {
if (text_autosizer_)
text_autosizer_->EndLayout(block_);
}
TextAutosizer::TableLayoutScope::TableLayoutScope(LayoutTable* table)
: LayoutScope(table) {
if (text_autosizer_) {
DCHECK(text_autosizer_->ShouldHandleLayout());
text_autosizer_->InflateAutoTable(table);
}
}
TextAutosizer::DeferUpdatePageInfo::DeferUpdatePageInfo(Page* page)
: main_frame_(page->DeprecatedLocalMainFrame()) {
if (TextAutosizer* text_autosizer =
main_frame_->GetDocument()->GetTextAutosizer()) {
DCHECK(!text_autosizer->update_page_info_deferred_);
text_autosizer->update_page_info_deferred_ = true;
}
}
TextAutosizer::NGLayoutScope::NGLayoutScope(const NGBlockNode& node,
LayoutUnit inline_size)
: text_autosizer_(node.GetLayoutBox()->GetDocument().GetTextAutosizer()),
block_(ToLayoutBlockFlow(node.GetLayoutBox())) {
if (!text_autosizer_ || !text_autosizer_->ShouldHandleLayout() ||
block_->IsLayoutNGListMarker()) {
// Bail if text autosizing isn't enabled, but also if this is a
// IsLayoutNGListMarker. They are super-small blocks, and using them to
// determine if we should autosize the text will typically always yield
// false, overriding whatever its parent (typically the list item) has
// already correctly determined.
text_autosizer_ = nullptr;
return;
}
// In order for the text autosizer to do anything useful at all, it needs to
// know the inline size of the block. So set it. LayoutNG normally writes back
// to the legacy tree *after* layout, but this one must be set before, at
// least if the autosizer is enabled.
block_->SetLogicalWidth(inline_size);
text_autosizer_->BeginLayout(block_, nullptr);
}
TextAutosizer::NGLayoutScope::~NGLayoutScope() {
if (text_autosizer_)
text_autosizer_->EndLayout(block_);
}
TextAutosizer::DeferUpdatePageInfo::~DeferUpdatePageInfo() {
if (TextAutosizer* text_autosizer =
main_frame_->GetDocument()->GetTextAutosizer()) {
DCHECK(text_autosizer->update_page_info_deferred_);
text_autosizer->update_page_info_deferred_ = false;
text_autosizer->UpdatePageInfoInAllFrames();
}
}
float TextAutosizer::ComputeAutosizedFontSize(float computed_size,
float multiplier,
float effective_zoom) {
DCHECK_GE(multiplier, 0);
// Somewhat arbitrary "pleasant" font size.
const float kPleasantSize = 16 * effective_zoom;
// Multiply fonts that the page author has specified to be larger than
// pleasantSize by less and less, until huge fonts are not increased at all.
// For specifiedSize between 0 and pleasantSize we directly apply the
// multiplier; hence for specifiedSize == pleasantSize, computedSize will be
// multiplier * pleasantSize. For greater specifiedSizes we want to
// gradually fade out the multiplier, so for every 1px increase in
// specifiedSize beyond pleasantSize we will only increase computedSize
// by gradientAfterPleasantSize px until we meet the
// computedSize = specifiedSize line, after which we stay on that line (so
// then every 1px increase in specifiedSize increases computedSize by 1px).
const float kGradientAfterPleasantSize = 0.5;
float auto_sized_size;
// Skip linear backoff for multipliers that shrink the size or when the font
// sizes are small.
if (multiplier <= 1 || computed_size <= kPleasantSize) {
auto_sized_size = multiplier * computed_size;
} else {
auto_sized_size =
multiplier * kPleasantSize +
kGradientAfterPleasantSize * (computed_size - kPleasantSize);
if (auto_sized_size < computed_size)
auto_sized_size = computed_size;
}
return auto_sized_size;
}
void TextAutosizer::CheckSuperclusterConsistency() {
HashSet<Supercluster*>& potentially_inconsistent_superclusters =
fingerprint_mapper_.GetPotentiallyInconsistentSuperclusters();
if (potentially_inconsistent_superclusters.IsEmpty())
return;
for (Supercluster* supercluster : potentially_inconsistent_superclusters) {
if (kHasEnoughText == supercluster->has_enough_text_to_autosize_)
continue;
float old_multipiler = supercluster->multiplier_;
supercluster->multiplier_ = 0;
supercluster->has_enough_text_to_autosize_ = kUnknownAmountOfText;
const LayoutBlock* width_provider =
MaxClusterWidthProvider(supercluster, nullptr);
if (!width_provider)
continue;
if (SuperclusterHasEnoughTextToAutosize(supercluster, width_provider,
true) == kHasEnoughText) {
for (auto* root : *supercluster->roots_) {
if (!root->EverHadLayout())
continue;
DCHECK(root);
SetAllTextNeedsLayout(root);
}
} else {
supercluster->multiplier_ = old_multipiler;
}
}
potentially_inconsistent_superclusters.clear();
}
void TextAutosizer::Trace(blink::Visitor* visitor) {
visitor->Trace(document_);
}
} // namespace blink