third_party/blink/renderer/modules/accessibility/ax_inline_text_box.cc

/*
 * 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:
 *
 * 1.  Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer.
 * 2.  Redistributions in binary form must reproduce the above copyright
 *     notice, this list of conditions and the following disclaimer in the
 *     documentation and/or other materials provided with the distribution.
 * 3.  Neither the name of Apple Computer, Inc. ("Apple") 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 APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY
 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY
 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
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 */

#include "third_party/blink/renderer/modules/accessibility/ax_inline_text_box.h"

#include "third_party/blink/renderer/core/dom/range.h"
#include "third_party/blink/renderer/core/layout/api/line_layout_api_shim.h"
#include "third_party/blink/renderer/core/layout/layout_text.h"
#include "third_party/blink/renderer/modules/accessibility/ax_object_cache_impl.h"
#include "third_party/blink/renderer/modules/accessibility/ax_position.h"
#include "third_party/blink/renderer/modules/accessibility/ax_range.h"
#include "third_party/blink/renderer/platform/geometry/layout_unit.h"

namespace blink {

AXInlineTextBox::AXInlineTextBox(
    scoped_refptr<AbstractInlineTextBox> inline_text_box,
    AXObjectCacheImpl& ax_object_cache)
    : AXObject(ax_object_cache), inline_text_box_(std::move(inline_text_box)) {}

void AXInlineTextBox::Init() {}

void AXInlineTextBox::Detach() {
  AXObject::Detach();
  inline_text_box_ = nullptr;
}

bool AXInlineTextBox::IsLineBreakingObject() const {
  if (IsDetached())
    return AXObject::IsLineBreakingObject();

  // If this object is a forced line break, or the parent is a <br>
  // element, then this object is line breaking.
  const AXObject* parent = ParentObject();
  return inline_text_box_->IsLineBreak() ||
         (parent && parent->RoleValue() == ax::mojom::Role::kLineBreak);
}

void AXInlineTextBox::GetRelativeBounds(AXObject** out_container,
                                        FloatRect& out_bounds_in_container,
                                        SkMatrix44& out_container_transform,
                                        bool* clips_children) const {
  *out_container = nullptr;
  out_bounds_in_container = FloatRect();
  out_container_transform.setIdentity();

  if (!inline_text_box_ || !ParentObject() ||
      !ParentObject()->GetLayoutObject())
    return;

  *out_container = ParentObject();
  out_bounds_in_container = FloatRect(inline_text_box_->LocalBounds());

  // Subtract the local bounding box of the parent because they're
  // both in the same coordinate system.
  FloatRect parent_bounding_box =
      ParentObject()->LocalBoundingBoxRectForAccessibility();
  out_bounds_in_container.MoveBy(-parent_bounding_box.Location());
}

bool AXInlineTextBox::ComputeAccessibilityIsIgnored(
    IgnoredReasons* ignored_reasons) const {
  AXObject* parent = ParentObject();
  if (!parent)
    return false;

  if (!parent->AccessibilityIsIgnored())
    return false;

  if (ignored_reasons)
    parent->ComputeAccessibilityIsIgnored(ignored_reasons);

  return true;
}

void AXInlineTextBox::TextCharacterOffsets(Vector<int>& offsets) const {
  if (!inline_text_box_)
    return;

  unsigned len = inline_text_box_->Len();
  Vector<float> widths;
  inline_text_box_->CharacterWidths(widths);
  DCHECK_EQ(widths.size(), len);
  offsets.resize(len);

  float width_so_far = 0;
  for (unsigned i = 0; i < len; i++) {
    width_so_far += widths[i];
    offsets[i] = roundf(width_so_far);
  }
}

void AXInlineTextBox::GetWordBoundaries(Vector<int>& word_starts,
                                        Vector<int>& word_ends) const {
  if (!inline_text_box_ ||
      inline_text_box_->GetText().ContainsOnlyWhitespaceOrEmpty())
    return;

  Vector<AbstractInlineTextBox::WordBoundaries> boundaries;
  inline_text_box_->GetWordBoundaries(boundaries);
  word_starts.ReserveCapacity(boundaries.size());
  word_ends.ReserveCapacity(boundaries.size());
  for (const auto& boundary : boundaries) {
    word_starts.push_back(boundary.start_index);
    word_ends.push_back(boundary.end_index);
  }
}

String AXInlineTextBox::GetName(ax::mojom::NameFrom& name_from,
                                AXObject::AXObjectVector* name_objects) const {
  if (!inline_text_box_)
    return String();

  name_from = ax::mojom::NameFrom::kContents;
  return inline_text_box_->GetText();
}

AXObject* AXInlineTextBox::ComputeParent() const {
  DCHECK(!IsDetached());
  if (!inline_text_box_ || !ax_object_cache_)
    return nullptr;
  LineLayoutText line_layout_text = inline_text_box_->GetLineLayoutItem();
  if (!line_layout_text)
    return nullptr;
  return ax_object_cache_->GetOrCreate(
      LineLayoutAPIShim::LayoutObjectFrom(line_layout_text));
}

// In addition to LTR and RTL direction, edit fields also support
// top to bottom and bottom to top via the CSS writing-mode property.
ax::mojom::TextDirection AXInlineTextBox::GetTextDirection() const {
  if (!inline_text_box_)
    return AXObject::GetTextDirection();

  switch (inline_text_box_->GetDirection()) {
    case AbstractInlineTextBox::kLeftToRight:
      return ax::mojom::TextDirection::kLtr;
    case AbstractInlineTextBox::kRightToLeft:
      return ax::mojom::TextDirection::kRtl;
    case AbstractInlineTextBox::kTopToBottom:
      return ax::mojom::TextDirection::kTtb;
    case AbstractInlineTextBox::kBottomToTop:
      return ax::mojom::TextDirection::kBtt;
  }

  return AXObject::GetTextDirection();
}

Node* AXInlineTextBox::GetNode() const {
  if (!inline_text_box_)
    return nullptr;

  return inline_text_box_->GetNode();
}

AXObject* AXInlineTextBox::NextOnLine() const {
  if (inline_text_box_->IsLast())
    return ParentObject()->NextOnLine();

  scoped_refptr<AbstractInlineTextBox> next_on_line =
      inline_text_box_->NextOnLine();
  if (next_on_line)
    return ax_object_cache_->GetOrCreate(next_on_line.get());

  return nullptr;
}

AXObject* AXInlineTextBox::PreviousOnLine() const {
  if (inline_text_box_->IsFirst())
    return ParentObject()->PreviousOnLine();

  scoped_refptr<AbstractInlineTextBox> previous_on_line =
      inline_text_box_->PreviousOnLine();
  if (previous_on_line)
    return ax_object_cache_->GetOrCreate(previous_on_line.get());

  return nullptr;
}

}  // namespace blink