1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809 810 811 812 813 814 815 816 817 818 819 820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854 855 856 857 858 859 860 861 862 863 864 865 866 867 868 869 870 871 872 873 874 875 876 877 878 879 880 881 882 883 884 885 886 887 888 889 890 891 892 893 894 895 896 897 898 899 900 901 902 903 904 905 906 907 908 909 910 911 912 913 914 915 916 917 918 919 920 921 922 923 924 925 926 927 928 929 930 931 932 933 934 935 936 937 938 939 940 941 942 943 944 945 946 947 948 949 950 951 952 953 954 955 956 957 958 959 960 961 962 963 964 965 966 967 968 969 970 971 972 973 974 975 976 977 978 979 980 981 982 983 984 985 986 987 988 989 990 991 992 993 994 995 996 997 998 999 1000 1001 1002 1003 1004 1005 1006 1007 1008 1009 1010 1011 1012 1013 1014 1015 1016 1017 1018 1019 1020 1021 1022 1023 1024 1025 1026 1027 1028 1029 1030 1031 1032 1033 1034 1035 1036 1037 1038 1039 1040 1041 1042 1043 1044 1045 1046 1047 1048 1049 1050 1051 1052 1053 1054 1055 1056 1057 1058 1059 1060 1061 1062 1063 1064 1065 1066 1067 1068 1069 1070 1071 1072 1073 1074 1075 1076 1077 1078 1079 1080 1081 1082 1083 1084 1085 1086 1087 1088 1089 1090 1091 1092 1093 1094 1095 1096 1097 1098 1099 1100 1101 1102 1103 1104 1105 1106 1107 1108 1109 1110 1111 1112 1113 1114 1115 1116 1117 1118 1119 1120 1121 1122 1123 1124 1125 1126 1127 1128 1129 1130 1131 1132 1133 1134 1135 1136 1137 1138 1139 1140 1141 1142 1143 1144 1145 1146 1147 1148 1149 1150 1151 1152 1153 1154 1155 1156 1157 1158 1159 1160 1161 1162 1163 1164 1165 1166 1167 1168 1169 1170 1171 1172 1173 1174 1175 1176 1177 1178 1179 1180 1181 1182 1183 1184 1185 1186 1187 1188 1189 1190 1191 1192 1193 1194 1195 1196 1197 1198 1199 1200 1201 1202 1203 1204 1205 1206 1207 1208 1209 1210 1211 1212 1213 1214 1215 1216 1217 1218 1219 1220 1221 1222 1223 1224 1225 1226 1227 1228 1229 1230 1231 1232 1233 1234 1235 1236 1237 1238 1239 1240 1241 1242 1243 1244 1245 1246 1247 1248 1249 1250
|
// Copyright 2024 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "components/pdf/renderer/pdf_accessibility_tree_builder.h"
#include <optional>
#include <queue>
#include <string>
#include "base/containers/fixed_flat_map.h"
#include "base/i18n/break_iterator.h"
#include "base/strings/utf_string_conversion_utils.h"
#include "components/strings/grit/components_strings.h"
#include "pdf/accessibility_structs.h"
#include "pdf/pdf_features.h"
#include "services/strings/grit/services_strings.h"
#include "third_party/blink/public/web/web_ax_object.h"
#include "ui/accessibility/accessibility_features.h"
#include "ui/accessibility/ax_enums.mojom-shared.h"
#include "ui/accessibility/ax_node_data.h"
#include "ui/base/l10n/l10n_util.h"
#include "ui/gfx/geometry/rect_f.h"
#include "ui/strings/grit/auto_image_annotation_strings.h"
namespace {
// Don't try to apply font size thresholds to automatically identify headings
// if the median font size is not at least this many points.
const float kMinimumFontSize = 5.0f;
// Don't try to apply paragraph break thresholds to automatically identify
// paragraph breaks if the median line break is not at least this many points.
const float kMinimumLineSpacing = 5.0f;
// Ratio between the font size of one text run and the median on the page
// for that text run to be considered to be a heading instead of normal text.
const float kHeadingFontSizeRatio = 1.2f;
// Ratio between the line spacing between two lines and the median on the
// page for that line spacing to be considered a paragraph break.
const float kParagraphLineSpacingRatio = 1.2f;
// This class is used as part of our heuristic to determine which text runs live
// on the same "line". As we process runs, we keep a weighted average of the
// top and bottom coordinates of the line, and if a new run falls within that
// range (within a threshold) it is considered part of the line.
class LineHelper {
public:
explicit LineHelper(
const std::vector<chrome_pdf::AccessibilityTextRunInfo>& text_runs)
: text_runs_(text_runs) {
StartNewLine(0);
}
LineHelper(const LineHelper&) = delete;
LineHelper& operator=(const LineHelper&) = delete;
void StartNewLine(size_t current_index) {
DCHECK(current_index == 0 || current_index < text_runs_->size());
start_index_ = current_index;
accumulated_weight_top_ = 0.0f;
accumulated_weight_bottom_ = 0.0f;
accumulated_width_ = 0.0f;
}
void ProcessNextRun(size_t run_index) {
DCHECK_LT(run_index, text_runs_->size());
RemoveOldRunsUpTo(run_index);
AddRun((*text_runs_)[run_index].bounds);
}
bool IsRunOnSameLine(size_t run_index) const {
DCHECK_LT(run_index, text_runs_->size());
// Calculate new top/bottom bounds for our line.
if (accumulated_width_ == 0.0f) {
return false;
}
float line_top = accumulated_weight_top_ / accumulated_width_;
float line_bottom = accumulated_weight_bottom_ / accumulated_width_;
// Look at the next run, and determine how much it overlaps the line.
const auto& run_bounds = (*text_runs_)[run_index].bounds;
if (run_bounds.height() == 0.0f) {
return false;
}
float clamped_top = std::max(line_top, run_bounds.y());
float clamped_bottom =
std::min(line_bottom, run_bounds.y() + run_bounds.height());
if (clamped_bottom < clamped_top) {
return false;
}
float coverage = (clamped_bottom - clamped_top) / (run_bounds.height());
// See if it falls within the line (within our threshold).
constexpr float kLineCoverageThreshold = 0.25f;
return coverage > kLineCoverageThreshold;
}
private:
void AddRun(const gfx::RectF& run_bounds) {
float run_width = fabsf(run_bounds.width());
accumulated_width_ += run_width;
accumulated_weight_top_ += run_bounds.y() * run_width;
accumulated_weight_bottom_ +=
(run_bounds.y() + run_bounds.height()) * run_width;
}
void RemoveRun(const gfx::RectF& run_bounds) {
float run_width = fabsf(run_bounds.width());
accumulated_width_ -= run_width;
accumulated_weight_top_ -= run_bounds.y() * run_width;
accumulated_weight_bottom_ -=
(run_bounds.y() + run_bounds.height()) * run_width;
}
void RemoveOldRunsUpTo(size_t stop_index) {
// Remove older runs from the weighted average if we've exceeded the
// threshold distance from them. We remove them to prevent e.g. drop-caps
// from unduly influencing future lines.
constexpr float kBoxRemoveWidthThreshold = 3.0f;
while (start_index_ < stop_index &&
accumulated_width_ > (*text_runs_)[start_index_].bounds.width() *
kBoxRemoveWidthThreshold) {
const auto& old_bounds = (*text_runs_)[start_index_].bounds;
RemoveRun(old_bounds);
start_index_++;
}
}
const raw_ref<const std::vector<chrome_pdf::AccessibilityTextRunInfo>>
text_runs_;
size_t start_index_;
float accumulated_weight_top_;
float accumulated_weight_bottom_;
float accumulated_width_;
};
bool BreakParagraph(
const std::vector<chrome_pdf::AccessibilityTextRunInfo>& text_runs,
uint32_t text_run_index,
float paragraph_spacing_threshold) {
// Check to see if its also a new paragraph, i.e., if the distance between
// lines is greater than the threshold. If there's no threshold, that
// means there weren't enough lines to compute an accurate median, so
// we compare against the line size instead.
float line_spacing = fabsf(text_runs[text_run_index + 1].bounds.y() -
text_runs[text_run_index].bounds.y());
return ((paragraph_spacing_threshold > 0 &&
line_spacing > paragraph_spacing_threshold) ||
(paragraph_spacing_threshold == 0 &&
line_spacing > kParagraphLineSpacingRatio *
text_runs[text_run_index].bounds.height()));
}
void BuildStaticNode(ui::AXNodeData** static_text_node,
std::string* static_text) {
// If we're in the middle of building a static text node, finish it before
// moving on to the next object.
if (*static_text_node) {
(*static_text_node)
->AddStringAttribute(ax::mojom::StringAttribute::kName, (*static_text));
static_text->clear();
}
*static_text_node = nullptr;
}
void ComputeParagraphAndHeadingThresholds(
const std::vector<chrome_pdf::AccessibilityTextRunInfo>& text_runs,
float* out_heading_font_size_threshold,
float* out_paragraph_spacing_threshold) {
// Scan over the font sizes and line spacing within this page and
// set heuristic thresholds so that text larger than the median font
// size can be marked as a heading, and spacing larger than the median
// line spacing can be a paragraph break.
std::vector<float> font_sizes;
std::vector<float> line_spacings;
for (size_t i = 0; i < text_runs.size(); ++i) {
font_sizes.push_back(text_runs[i].style.font_size);
if (i > 0) {
const auto& cur = text_runs[i].bounds;
const auto& prev = text_runs[i - 1].bounds;
if (cur.y() > prev.y() + prev.height() / 2) {
line_spacings.push_back(cur.y() - prev.y());
}
}
}
if (font_sizes.size() > 2) {
std::sort(font_sizes.begin(), font_sizes.end());
float median_font_size = font_sizes[font_sizes.size() / 2];
if (median_font_size > kMinimumFontSize) {
*out_heading_font_size_threshold =
median_font_size * kHeadingFontSizeRatio;
}
}
if (line_spacings.size() > 4) {
std::sort(line_spacings.begin(), line_spacings.end());
float median_line_spacing = line_spacings[line_spacings.size() / 2];
if (median_line_spacing > kMinimumLineSpacing) {
*out_paragraph_spacing_threshold =
median_line_spacing * kParagraphLineSpacingRatio;
}
}
}
void ConnectPreviousAndNextOnLine(ui::AXNodeData* previous_on_line_node,
ui::AXNodeData* next_on_line_node) {
previous_on_line_node->AddIntAttribute(ax::mojom::IntAttribute::kNextOnLineId,
next_on_line_node->id);
next_on_line_node->AddIntAttribute(ax::mojom::IntAttribute::kPreviousOnLineId,
previous_on_line_node->id);
}
ax::mojom::Role GetRoleForButtonType(chrome_pdf::ButtonType button_type) {
switch (button_type) {
case chrome_pdf::ButtonType::kRadioButton:
return ax::mojom::Role::kRadioButton;
case chrome_pdf::ButtonType::kCheckBox:
return ax::mojom::Role::kCheckBox;
case chrome_pdf::ButtonType::kPushButton:
return ax::mojom::Role::kButton;
}
}
std::string GetTextRunCharsAsUTF8(
const chrome_pdf::AccessibilityTextRunInfo& text_run,
const std::vector<chrome_pdf::AccessibilityCharInfo>& chars,
int char_index) {
std::string chars_utf8;
for (uint32_t i = 0; i < text_run.len; ++i) {
base::WriteUnicodeCharacter(
static_cast<base_icu::UChar32>(chars[char_index + i].unicode_character),
&chars_utf8);
}
return chars_utf8;
}
std::vector<int32_t> GetTextRunCharOffsets(
const chrome_pdf::AccessibilityTextRunInfo& text_run,
const std::vector<chrome_pdf::AccessibilityCharInfo>& chars,
int char_index) {
std::vector<int32_t> char_offsets(text_run.len);
double offset = 0.0;
for (uint32_t i = 0; i < text_run.len; ++i) {
offset += chars[char_index + i].char_width;
char_offsets[i] = floor(offset);
}
return char_offsets;
}
template <typename T>
bool IsObjectInTextRun(const std::vector<T>& objects,
uint32_t object_index,
size_t text_run_index) {
return (object_index < objects.size() &&
objects[object_index].text_run_index <= text_run_index);
}
template <typename T>
bool IsObjectWithRangeInTextRun(const std::vector<T>& objects,
uint32_t object_index,
size_t text_run_index) {
return (object_index < objects.size() &&
objects[object_index].text_range.index <= text_run_index);
}
bool IsTextRenderModeFill(const chrome_pdf::AccessibilityTextRenderMode& mode) {
switch (mode) {
case chrome_pdf::AccessibilityTextRenderMode::kFill:
case chrome_pdf::AccessibilityTextRenderMode::kFillStroke:
case chrome_pdf::AccessibilityTextRenderMode::kFillClip:
case chrome_pdf::AccessibilityTextRenderMode::kFillStrokeClip:
return true;
default:
return false;
}
}
bool IsTextRenderModeStroke(
const chrome_pdf::AccessibilityTextRenderMode& mode) {
switch (mode) {
case chrome_pdf::AccessibilityTextRenderMode::kStroke:
case chrome_pdf::AccessibilityTextRenderMode::kFillStroke:
case chrome_pdf::AccessibilityTextRenderMode::kStrokeClip:
case chrome_pdf::AccessibilityTextRenderMode::kFillStrokeClip:
return true;
default:
return false;
}
}
size_t NormalizeTextRunIndex(uint32_t object_end_text_run_index,
size_t current_text_run_index) {
return std::max<size_t>(
object_end_text_run_index,
current_text_run_index ? current_text_run_index - 1 : 0);
}
// Please keep the below map as close as possible to the list defined in the PDF
// Specification, ISO 32000-1:2008, table 333.
ax::mojom::Role StructureElementTypeToAccessibilityRole(
const std::string& element_type) {
static constexpr auto kStructureElementTypeToAccessibilityRoleMap =
base::MakeFixedFlatMap<std::string_view, ax::mojom::Role>(
{{"Document", ax::mojom::Role::kDocument},
{"Part", ax::mojom::Role::kDocPart},
{"Art", ax::mojom::Role::kArticle},
{"Sect", ax::mojom::Role::kSection},
{"Div", ax::mojom::Role::kGenericContainer},
{"BlockQuote", ax::mojom::Role::kBlockquote},
{"Caption", ax::mojom::Role::kCaption},
{"TOC", ax::mojom::Role::kDocToc},
{"TOCI", ax::mojom::Role::kListItem},
{"Index", ax::mojom::Role::kDocIndex},
{"P", ax::mojom::Role::kParagraph},
{"H", ax::mojom::Role::kHeading},
{"H1", ax::mojom::Role::kHeading},
{"H2", ax::mojom::Role::kHeading},
{"H3", ax::mojom::Role::kHeading},
{"H4", ax::mojom::Role::kHeading},
{"H5", ax::mojom::Role::kHeading},
{"H6", ax::mojom::Role::kHeading},
{"L", ax::mojom::Role::kList},
{"LI", ax::mojom::Role::kListItem},
{"Lbl", ax::mojom::Role::kListMarker},
{"LBody", ax::mojom::Role::kNone}, // Presentational.
{"Table", ax::mojom::Role::kTable},
{"TR", ax::mojom::Role::kRow},
{"TH", ax::mojom::Role::kRowHeader},
{"THead", ax::mojom::Role::kRowGroup},
{"TBody", ax::mojom::Role::kRowGroup},
{"TFoot", ax::mojom::Role::kRowGroup},
{"TD", ax::mojom::Role::kCell},
{"Span", ax::mojom::Role::kStaticText},
{"Link", ax::mojom::Role::kLink},
{"Figure", ax::mojom::Role::kFigure},
{"Formula", ax::mojom::Role::kMath},
{"Form", ax::mojom::Role::kForm}});
if (auto iter =
kStructureElementTypeToAccessibilityRoleMap.find(element_type);
iter != kStructureElementTypeToAccessibilityRoleMap.end()) {
return iter->second;
}
// Return something that could at least make some sense, other than
// `kUnknown`.
return ax::mojom::Role::kParagraph;
}
std::optional<uint32_t> StructureElementTypeToHeadingLevel(
const std::string& element_type) {
if (StructureElementTypeToAccessibilityRole(element_type) ==
ax::mojom::Role::kHeading) {
if (element_type == "H" || element_type == "H1") {
return 1;
} else if (element_type == "H2") {
return 2;
} else if (element_type == "H3") {
return 3;
} else if (element_type == "H4") {
return 4;
} else if (element_type == "H5") {
return 5;
} else if (element_type == "H6") {
return 6;
}
}
return std::nullopt;
}
} // namespace
namespace pdf {
PdfAccessibilityTreeBuilder::PdfAccessibilityTreeBuilder(
bool mark_headings_using_heuristic,
const std::vector<chrome_pdf::AccessibilityTextRunInfo>& text_runs,
const std::vector<chrome_pdf::AccessibilityCharInfo>& chars,
const chrome_pdf::AccessibilityPageObjects& page_objects,
const chrome_pdf::AccessibilityPageInfo& page_info,
uint32_t page_index,
ui::AXNodeData* root_node,
blink::WebAXObject* container_obj,
std::vector<std::unique_ptr<ui::AXNodeData>>* nodes,
std::map<int32_t, chrome_pdf::PageCharacterIndex>*
node_id_to_page_char_index,
std::map<int32_t, PdfAccessibilityTree::AnnotationInfo>*
node_id_to_annotation_info
)
: mark_headings_using_heuristic_(mark_headings_using_heuristic),
text_runs_(text_runs),
chars_(chars),
links_(page_objects.links),
images_(page_objects.images),
highlights_(page_objects.highlights),
text_fields_(page_objects.form_fields.text_fields),
buttons_(page_objects.form_fields.buttons),
choice_fields_(page_objects.form_fields.choice_fields),
page_index_(page_index),
root_node_(root_node),
container_obj_(container_obj),
nodes_(nodes),
node_id_to_page_char_index_(node_id_to_page_char_index),
node_id_to_annotation_info_(node_id_to_annotation_info)
{
page_node_ = CreateAndAppendNode(ax::mojom::Role::kRegion,
ax::mojom::Restriction::kReadOnly);
page_node_->AddStringAttribute(
ax::mojom::StringAttribute::kName,
l10n_util::GetPluralStringFUTF8(IDS_PDF_PAGE_INDEX, page_index + 1));
page_node_->AddBoolAttribute(ax::mojom::BoolAttribute::kIsPageBreakingObject,
true);
page_node_->relative_bounds.bounds = gfx::RectF(page_info.bounds);
root_node_->relative_bounds.bounds.Union(page_node_->relative_bounds.bounds);
root_node_->child_ids.push_back(page_node_->id);
if (!text_runs.empty()) {
text_run_start_indices_.reserve(text_runs.size());
text_run_start_indices_.push_back(0);
for (size_t i = 0; i < text_runs.size() - 1; ++i) {
text_run_start_indices_.push_back(text_run_start_indices_[i] +
text_runs[i].len);
}
}
}
PdfAccessibilityTreeBuilder::~PdfAccessibilityTreeBuilder() = default;
void PdfAccessibilityTreeBuilder::BuildPageTree() {
ComputeParagraphAndHeadingThresholds(*text_runs_,
&heading_font_size_threshold_,
¶graph_spacing_threshold_);
ui::AXNodeData* block_node = nullptr;
ui::AXNodeData* static_text_node = nullptr;
ui::AXNodeData* previous_on_line_node = nullptr;
std::string static_text;
LineHelper line_helper(*text_runs_);
bool pdf_forms_enabled =
base::FeatureList::IsEnabled(chrome_pdf::features::kAccessiblePDFForm);
#if BUILDFLAG(ENABLE_SCREEN_AI_SERVICE)
bool ocr_block = false;
bool has_ocr_text = false;
#endif
for (size_t text_run_index = 0; text_run_index < text_runs_->size();
++text_run_index) {
const chrome_pdf::AccessibilityTextRunInfo& text_run =
(*text_runs_)[text_run_index];
#if BUILDFLAG(ENABLE_SCREEN_AI_SERVICE)
// OCR text should be marked by nodes before and after it.
bool ocr_block_start = text_run.is_searchified && !ocr_block;
bool ocr_block_end = !text_run.is_searchified && ocr_block;
if (ocr_block_start || ocr_block_end) {
// If already inside a block, end it.
// PDF searchifier only processes pages that have no text, hence OCR text
// is never added in the middle of a paragraph.
if (block_node) {
BuildStaticNode(&static_text_node, &static_text);
block_node = nullptr;
}
CHECK(ocr_block_start || text_run_index);
gfx::PointF position =
ocr_block_start
? text_run.bounds.origin()
: (*text_runs_)[text_run_index - 1].bounds.bottom_right();
page_node_->child_ids.push_back(
CreateOcrWrapperNode(position, ocr_block_start)->id);
ocr_block = ocr_block_start;
has_ocr_text = true;
}
#endif // BUILDFLAG(ENABLE_SCREEN_AI_SERVICE)
// If we don't have a block level node, create one.
if (!block_node) {
block_node =
CreateBlockLevelNode(text_run.tag_type, text_run.style.font_size);
page_node_->child_ids.push_back(block_node->id);
}
// If the `text_run_index` is less than or equal to the link's
// `text_run_index`, then push the link node in the block.
if (IsObjectWithRangeInTextRun(*links_, current_link_index_,
text_run_index)) {
BuildStaticNode(&static_text_node, &static_text);
const chrome_pdf::AccessibilityLinkInfo& link =
(*links_)[current_link_index_++];
AddLinkToParaNode(link, block_node, &previous_on_line_node,
&text_run_index);
if (link.text_range.count == 0) {
continue;
}
} else if (IsObjectInTextRun(*images_, current_image_index_,
text_run_index)) {
BuildStaticNode(&static_text_node, &static_text);
AddImageToParaNode((*images_)[current_image_index_++], block_node,
&text_run_index);
continue;
} else if (IsObjectWithRangeInTextRun(
*highlights_, current_highlight_index_, text_run_index)) {
BuildStaticNode(&static_text_node, &static_text);
AddHighlightToParaNode((*highlights_)[current_highlight_index_++],
block_node, &previous_on_line_node,
&text_run_index);
} else if (IsObjectInTextRun(*text_fields_, current_text_field_index_,
text_run_index) &&
pdf_forms_enabled) {
BuildStaticNode(&static_text_node, &static_text);
AddTextFieldToParaNode((*text_fields_)[current_text_field_index_++],
block_node, &text_run_index);
continue;
} else if (IsObjectInTextRun(*buttons_, current_button_index_,
text_run_index) &&
pdf_forms_enabled) {
BuildStaticNode(&static_text_node, &static_text);
AddButtonToParaNode((*buttons_)[current_button_index_++], block_node,
&text_run_index);
continue;
} else if (IsObjectInTextRun(*choice_fields_, current_choice_field_index_,
text_run_index) &&
pdf_forms_enabled) {
BuildStaticNode(&static_text_node, &static_text);
AddChoiceFieldToParaNode((*choice_fields_)[current_choice_field_index_++],
block_node, &text_run_index);
continue;
} else {
chrome_pdf::PageCharacterIndex page_char_index = {
page_index_, text_run_start_indices_[text_run_index]};
// This node is for the text inside the block, it includes the text of all
// of the text runs.
if (!static_text_node) {
static_text_node = CreateStaticTextNode(page_char_index);
block_node->child_ids.push_back(static_text_node->id);
}
// Add this text run to the current static text node.
ui::AXNodeData* inline_text_box_node =
CreateInlineTextBoxNode(text_run, page_char_index);
static_text_node->child_ids.push_back(inline_text_box_node->id);
static_text += inline_text_box_node->GetStringAttribute(
ax::mojom::StringAttribute::kName);
block_node->relative_bounds.bounds.Union(
inline_text_box_node->relative_bounds.bounds);
static_text_node->relative_bounds.bounds.Union(
inline_text_box_node->relative_bounds.bounds);
if (previous_on_line_node) {
ConnectPreviousAndNextOnLine(previous_on_line_node,
inline_text_box_node);
} else {
line_helper.StartNewLine(text_run_index);
}
line_helper.ProcessNextRun(text_run_index);
if (text_run_index < text_runs_->size() - 1) {
if (line_helper.IsRunOnSameLine(text_run_index + 1)) {
// The next run is on the same line.
previous_on_line_node = inline_text_box_node;
} else {
// The next run is on a new line.
previous_on_line_node = nullptr;
}
}
}
if (text_run_index == text_runs_->size() - 1) {
BuildStaticNode(&static_text_node, &static_text);
break;
}
if (!previous_on_line_node) {
if (BreakParagraph(*text_runs_, text_run_index,
paragraph_spacing_threshold_)) {
BuildStaticNode(&static_text_node, &static_text);
block_node = nullptr;
}
}
}
#if BUILDFLAG(ENABLE_SCREEN_AI_SERVICE)
// Add the wrapper node if still in OCR block and text runs finish.
if (ocr_block) {
page_node_->child_ids.push_back(
CreateOcrWrapperNode(text_runs_->back().bounds.bottom_right(),
/*start=*/false)
->id);
}
AddRemainingAnnotations(block_node, has_ocr_text);
#else
AddRemainingAnnotations(block_node);
#endif
}
void PdfAccessibilityTreeBuilder::AddWordStartsAndEnds(
ui::AXNodeData* inline_text_box) {
std::u16string text =
inline_text_box->GetString16Attribute(ax::mojom::StringAttribute::kName);
base::i18n::BreakIterator iter(text, base::i18n::BreakIterator::BREAK_WORD);
if (!iter.Init()) {
return;
}
std::vector<int32_t> word_starts;
std::vector<int32_t> word_ends;
while (iter.Advance()) {
if (iter.IsWord()) {
word_starts.push_back(iter.prev());
word_ends.push_back(iter.pos());
}
}
inline_text_box->AddIntListAttribute(ax::mojom::IntListAttribute::kWordStarts,
word_starts);
inline_text_box->AddIntListAttribute(ax::mojom::IntListAttribute::kWordEnds,
word_ends);
}
ui::AXNodeData* PdfAccessibilityTreeBuilder::CreateAndAppendNode(
ax::mojom::Role role,
ax::mojom::Restriction restriction) {
std::unique_ptr<ui::AXNodeData> node = std::make_unique<ui::AXNodeData>();
node->id = container_obj_->GenerateAXID();
node->role = role;
node->SetRestriction(restriction);
// All nodes have coordinates relative to the root node.
if (root_node_) {
node->relative_bounds.offset_container_id = root_node_->id;
}
ui::AXNodeData* node_ptr = node.get();
nodes_->push_back(std::move(node));
return node_ptr;
}
ui::AXNodeData* PdfAccessibilityTreeBuilder::CreateBlockLevelNode(
const std::string& text_run_type,
float font_size) {
ui::AXNodeData* block_node = CreateAndAppendNode(
StructureElementTypeToAccessibilityRole(text_run_type),
ax::mojom::Restriction::kReadOnly);
block_node->AddBoolAttribute(ax::mojom::BoolAttribute::kIsLineBreakingObject,
true);
if (std::optional<uint32_t> level =
StructureElementTypeToHeadingLevel(text_run_type);
level) {
block_node->AddIntAttribute(ax::mojom::IntAttribute::kHierarchicalLevel,
*level);
// TODO(crbug.com/40707542): Set the HTML tag to "h*" by creating a helper
// in `AXEnumUtils`.
}
if (mark_headings_using_heuristic_ && heading_font_size_threshold_ > 0 &&
font_size > heading_font_size_threshold_) {
block_node->role = ax::mojom::Role::kHeading;
block_node->AddIntAttribute(ax::mojom::IntAttribute::kHierarchicalLevel, 2);
block_node->AddStringAttribute(ax::mojom::StringAttribute::kHtmlTag, "h2");
}
return block_node;
}
ui::AXNodeData* PdfAccessibilityTreeBuilder::CreateStaticTextNode() {
ui::AXNodeData* static_text_node = CreateAndAppendNode(
ax::mojom::Role::kStaticText, ax::mojom::Restriction::kReadOnly);
static_text_node->SetNameFrom(ax::mojom::NameFrom::kContents);
return static_text_node;
}
ui::AXNodeData* PdfAccessibilityTreeBuilder::CreateStaticTextNode(
const chrome_pdf::PageCharacterIndex& page_char_index) {
ui::AXNodeData* static_text_node = CreateStaticTextNode();
node_id_to_page_char_index_->emplace(static_text_node->id, page_char_index);
return static_text_node;
}
ui::AXNodeData* PdfAccessibilityTreeBuilder::CreateInlineTextBoxNode(
const chrome_pdf::AccessibilityTextRunInfo& text_run,
const chrome_pdf::PageCharacterIndex& page_char_index) {
ui::AXNodeData* inline_text_box_node = CreateAndAppendNode(
ax::mojom::Role::kInlineTextBox, ax::mojom::Restriction::kReadOnly);
inline_text_box_node->SetNameFrom(ax::mojom::NameFrom::kContents);
std::string chars__utf8 =
GetTextRunCharsAsUTF8(text_run, *chars_, page_char_index.char_index);
inline_text_box_node->AddStringAttribute(ax::mojom::StringAttribute::kName,
chars__utf8);
inline_text_box_node->AddIntAttribute(
ax::mojom::IntAttribute::kTextDirection,
static_cast<uint32_t>(text_run.direction));
inline_text_box_node->AddStringAttribute(
ax::mojom::StringAttribute::kFontFamily, text_run.style.font_name);
inline_text_box_node->AddFloatAttribute(ax::mojom::FloatAttribute::kFontSize,
text_run.style.font_size);
inline_text_box_node->AddFloatAttribute(
ax::mojom::FloatAttribute::kFontWeight, text_run.style.font_weight);
if (text_run.style.is_italic) {
inline_text_box_node->AddTextStyle(ax::mojom::TextStyle::kItalic);
}
if (text_run.style.is_bold) {
inline_text_box_node->AddTextStyle(ax::mojom::TextStyle::kBold);
}
if (IsTextRenderModeFill(text_run.style.render_mode)) {
inline_text_box_node->AddIntAttribute(ax::mojom::IntAttribute::kColor,
text_run.style.fill_color);
} else if (IsTextRenderModeStroke(text_run.style.render_mode)) {
inline_text_box_node->AddIntAttribute(ax::mojom::IntAttribute::kColor,
text_run.style.stroke_color);
}
inline_text_box_node->relative_bounds.bounds =
text_run.bounds + page_node_->relative_bounds.bounds.OffsetFromOrigin();
std::vector<int32_t> char_offsets =
GetTextRunCharOffsets(text_run, *chars_, page_char_index.char_index);
inline_text_box_node->AddIntListAttribute(
ax::mojom::IntListAttribute::kCharacterOffsets, char_offsets);
AddWordStartsAndEnds(inline_text_box_node);
node_id_to_page_char_index_->emplace(inline_text_box_node->id,
page_char_index);
return inline_text_box_node;
}
ui::AXNodeData* PdfAccessibilityTreeBuilder::CreateLinkNode(
const chrome_pdf::AccessibilityLinkInfo& link) {
ui::AXNodeData* link_node = CreateAndAppendNode(
ax::mojom::Role::kLink, ax::mojom::Restriction::kReadOnly);
link_node->AddStringAttribute(ax::mojom::StringAttribute::kUrl, link.url);
link_node->AddStringAttribute(ax::mojom::StringAttribute::kName,
std::string());
link_node->relative_bounds.bounds = link.bounds;
link_node->SetDefaultActionVerb(ax::mojom::DefaultActionVerb::kJump);
node_id_to_annotation_info_->emplace(
link_node->id,
PdfAccessibilityTree::AnnotationInfo(page_index_, link.index_in_page));
return link_node;
}
ui::AXNodeData* PdfAccessibilityTreeBuilder::CreateImageNode(
const chrome_pdf::AccessibilityImageInfo& image) {
ui::AXNodeData* image_node = CreateAndAppendNode(
ax::mojom::Role::kImage, ax::mojom::Restriction::kReadOnly);
if (image.alt_text.empty()) {
image_node->AddStringAttribute(
ax::mojom::StringAttribute::kName,
l10n_util::GetStringUTF8(IDS_AX_UNLABELED_IMAGE_ROLE_DESCRIPTION));
} else {
image_node->AddStringAttribute(ax::mojom::StringAttribute::kName,
image.alt_text);
}
image_node->relative_bounds.bounds = image.bounds;
return image_node;
}
ui::AXNodeData* PdfAccessibilityTreeBuilder::CreateHighlightNode(
const chrome_pdf::AccessibilityHighlightInfo& highlight) {
ui::AXNodeData* highlight_node =
CreateAndAppendNode(ax::mojom::Role::kPdfActionableHighlight,
ax::mojom::Restriction::kReadOnly);
highlight_node->AddStringAttribute(
ax::mojom::StringAttribute::kRoleDescription,
l10n_util::GetStringUTF8(IDS_AX_ROLE_DESCRIPTION_PDF_HIGHLIGHT));
highlight_node->AddStringAttribute(ax::mojom::StringAttribute::kName,
std::string());
highlight_node->relative_bounds.bounds = highlight.bounds;
highlight_node->AddIntAttribute(ax::mojom::IntAttribute::kBackgroundColor,
highlight.color);
return highlight_node;
}
ui::AXNodeData* PdfAccessibilityTreeBuilder::CreatePopupNoteNode(
const chrome_pdf::AccessibilityHighlightInfo& highlight) {
ui::AXNodeData* popup_note_node = CreateAndAppendNode(
ax::mojom::Role::kNote, ax::mojom::Restriction::kReadOnly);
popup_note_node->AddStringAttribute(
ax::mojom::StringAttribute::kRoleDescription,
l10n_util::GetStringUTF8(IDS_AX_ROLE_DESCRIPTION_PDF_POPUP_NOTE));
popup_note_node->relative_bounds.bounds = highlight.bounds;
ui::AXNodeData* static_popup_note_text_node = CreateAndAppendNode(
ax::mojom::Role::kStaticText, ax::mojom::Restriction::kReadOnly);
static_popup_note_text_node->SetNameFrom(ax::mojom::NameFrom::kContents);
static_popup_note_text_node->AddStringAttribute(
ax::mojom::StringAttribute::kName, highlight.note_text);
static_popup_note_text_node->relative_bounds.bounds = highlight.bounds;
popup_note_node->child_ids.push_back(static_popup_note_text_node->id);
return popup_note_node;
}
ui::AXNodeData* PdfAccessibilityTreeBuilder::CreateTextFieldNode(
const chrome_pdf::AccessibilityTextFieldInfo& text_field) {
ax::mojom::Restriction restriction = text_field.is_read_only
? ax::mojom::Restriction::kReadOnly
: ax::mojom::Restriction::kNone;
ui::AXNodeData* text_field_node =
CreateAndAppendNode(ax::mojom::Role::kTextField, restriction);
text_field_node->AddStringAttribute(ax::mojom::StringAttribute::kName,
text_field.name);
text_field_node->AddStringAttribute(ax::mojom::StringAttribute::kValue,
text_field.value);
text_field_node->AddState(ax::mojom::State::kFocusable);
if (text_field.is_required) {
text_field_node->AddState(ax::mojom::State::kRequired);
}
if (text_field.is_password) {
text_field_node->AddState(ax::mojom::State::kProtected);
}
text_field_node->relative_bounds.bounds = text_field.bounds;
return text_field_node;
}
ui::AXNodeData* PdfAccessibilityTreeBuilder::CreateButtonNode(
const chrome_pdf::AccessibilityButtonInfo& button) {
ax::mojom::Restriction restriction = button.is_read_only
? ax::mojom::Restriction::kReadOnly
: ax::mojom::Restriction::kNone;
ui::AXNodeData* button_node =
CreateAndAppendNode(GetRoleForButtonType(button.type), restriction);
button_node->AddStringAttribute(ax::mojom::StringAttribute::kName,
button.name);
button_node->AddState(ax::mojom::State::kFocusable);
if (button.type == chrome_pdf::ButtonType::kRadioButton ||
button.type == chrome_pdf::ButtonType::kCheckBox) {
ax::mojom::CheckedState checkedState = button.is_checked
? ax::mojom::CheckedState::kTrue
: ax::mojom::CheckedState::kNone;
button_node->SetCheckedState(checkedState);
button_node->AddStringAttribute(ax::mojom::StringAttribute::kValue,
button.value);
button_node->AddIntAttribute(ax::mojom::IntAttribute::kSetSize,
button.control_count);
button_node->AddIntAttribute(ax::mojom::IntAttribute::kPosInSet,
button.control_index + 1);
button_node->SetDefaultActionVerb(ax::mojom::DefaultActionVerb::kCheck);
} else {
button_node->SetDefaultActionVerb(ax::mojom::DefaultActionVerb::kPress);
}
button_node->relative_bounds.bounds = button.bounds;
return button_node;
}
ui::AXNodeData* PdfAccessibilityTreeBuilder::CreateListboxOptionNode(
const chrome_pdf::AccessibilityChoiceFieldOptionInfo& choice_field_option,
ax::mojom::Restriction restriction) {
ui::AXNodeData* listbox_option_node =
CreateAndAppendNode(ax::mojom::Role::kListBoxOption, restriction);
listbox_option_node->AddStringAttribute(ax::mojom::StringAttribute::kName,
choice_field_option.name);
listbox_option_node->AddBoolAttribute(ax::mojom::BoolAttribute::kSelected,
choice_field_option.is_selected);
listbox_option_node->AddState(ax::mojom::State::kFocusable);
listbox_option_node->SetDefaultActionVerb(
ax::mojom::DefaultActionVerb::kSelect);
return listbox_option_node;
}
ui::AXNodeData* PdfAccessibilityTreeBuilder::CreateListboxNode(
const chrome_pdf::AccessibilityChoiceFieldInfo& choice_field,
ui::AXNodeData* control_node) {
ax::mojom::Restriction restriction = choice_field.is_read_only
? ax::mojom::Restriction::kReadOnly
: ax::mojom::Restriction::kNone;
ui::AXNodeData* listbox_node =
CreateAndAppendNode(ax::mojom::Role::kListBox, restriction);
if (choice_field.type != chrome_pdf::ChoiceFieldType::kComboBox) {
listbox_node->AddStringAttribute(ax::mojom::StringAttribute::kName,
choice_field.name);
}
ui::AXNodeData* first_selected_option = nullptr;
for (const chrome_pdf::AccessibilityChoiceFieldOptionInfo& option :
choice_field.options) {
ui::AXNodeData* listbox_option_node =
CreateListboxOptionNode(option, restriction);
if (!first_selected_option && listbox_option_node->GetBoolAttribute(
ax::mojom::BoolAttribute::kSelected)) {
first_selected_option = listbox_option_node;
}
// TODO(crbug.com/40661774): Add `listbox_option_node` specific bounds
// here.
listbox_option_node->relative_bounds.bounds = choice_field.bounds;
listbox_node->child_ids.push_back(listbox_option_node->id);
}
if (control_node && first_selected_option) {
control_node->AddIntAttribute(ax::mojom::IntAttribute::kActivedescendantId,
first_selected_option->id);
}
if (choice_field.is_multi_select) {
listbox_node->AddState(ax::mojom::State::kMultiselectable);
}
listbox_node->AddState(ax::mojom::State::kFocusable);
listbox_node->relative_bounds.bounds = choice_field.bounds;
return listbox_node;
}
ui::AXNodeData* PdfAccessibilityTreeBuilder::CreateComboboxInputNode(
const chrome_pdf::AccessibilityChoiceFieldInfo& choice_field,
ax::mojom::Restriction restriction) {
ax::mojom::Role input_role = choice_field.has_editable_text_box
? ax::mojom::Role::kTextFieldWithComboBox
: ax::mojom::Role::kComboBoxMenuButton;
ui::AXNodeData* combobox_input_node =
CreateAndAppendNode(input_role, restriction);
combobox_input_node->AddStringAttribute(ax::mojom::StringAttribute::kName,
choice_field.name);
for (const chrome_pdf::AccessibilityChoiceFieldOptionInfo& option :
choice_field.options) {
if (option.is_selected) {
combobox_input_node->AddStringAttribute(
ax::mojom::StringAttribute::kValue, option.name);
break;
}
}
combobox_input_node->AddState(ax::mojom::State::kFocusable);
combobox_input_node->relative_bounds.bounds = choice_field.bounds;
if (input_role == ax::mojom::Role::kComboBoxMenuButton) {
combobox_input_node->SetDefaultActionVerb(
ax::mojom::DefaultActionVerb::kOpen);
}
return combobox_input_node;
}
ui::AXNodeData* PdfAccessibilityTreeBuilder::CreateComboboxNode(
const chrome_pdf::AccessibilityChoiceFieldInfo& choice_field) {
ax::mojom::Restriction restriction = choice_field.is_read_only
? ax::mojom::Restriction::kReadOnly
: ax::mojom::Restriction::kNone;
ui::AXNodeData* combobox_node =
CreateAndAppendNode(ax::mojom::Role::kComboBoxGrouping, restriction);
ui::AXNodeData* input_element =
CreateComboboxInputNode(choice_field, restriction);
ui::AXNodeData* list_element = CreateListboxNode(choice_field, input_element);
input_element->AddIntListAttribute(ax::mojom::IntListAttribute::kControlsIds,
std::vector<int32_t>{list_element->id});
combobox_node->child_ids.push_back(input_element->id);
combobox_node->child_ids.push_back(list_element->id);
combobox_node->AddState(ax::mojom::State::kFocusable);
combobox_node->relative_bounds.bounds = choice_field.bounds;
return combobox_node;
}
ui::AXNodeData* PdfAccessibilityTreeBuilder::CreateChoiceFieldNode(
const chrome_pdf::AccessibilityChoiceFieldInfo& choice_field) {
switch (choice_field.type) {
case chrome_pdf::ChoiceFieldType::kListBox:
return CreateListboxNode(choice_field, /*control_node=*/nullptr);
case chrome_pdf::ChoiceFieldType::kComboBox:
return CreateComboboxNode(choice_field);
}
}
#if BUILDFLAG(ENABLE_SCREEN_AI_SERVICE)
ui::AXNodeData* PdfAccessibilityTreeBuilder::CreateOcrWrapperNode(
const gfx::PointF& position,
bool start) {
ui::AXNodeData* wrapper_node = CreateAndAppendNode(
start ? ax::mojom::Role::kBanner : ax::mojom::Role::kContentInfo,
ax::mojom::Restriction::kReadOnly);
wrapper_node->relative_bounds.bounds = gfx::RectF(position, gfx::SizeF(1, 1));
ui::AXNodeData* text_node = CreateStaticTextNode();
text_node->SetNameChecked(l10n_util::GetStringUTF8(
start ? IDS_PDF_OCR_RESULT_BEGIN : IDS_PDF_OCR_RESULT_END));
text_node->relative_bounds.bounds = wrapper_node->relative_bounds.bounds;
wrapper_node->child_ids.push_back(text_node->id);
return wrapper_node;
}
#endif // BUILDFLAG(ENABLE_SCREEN_AI_SERVICE)
void PdfAccessibilityTreeBuilder::AddTextToAXNode(
size_t start_text_run_index,
uint32_t end_text_run_index,
ui::AXNodeData* ax_node,
ui::AXNodeData** previous_on_line_node) {
chrome_pdf::PageCharacterIndex page_char_index = {
page_index_, text_run_start_indices_[start_text_run_index]};
ui::AXNodeData* ax_static_text_node = CreateStaticTextNode(page_char_index);
ax_node->child_ids.push_back(ax_static_text_node->id);
// Accumulate the text of the node.
std::string ax_name;
LineHelper line_helper(*text_runs_);
for (size_t text_run_index = start_text_run_index;
text_run_index <= end_text_run_index; ++text_run_index) {
const chrome_pdf::AccessibilityTextRunInfo& text_run =
(*text_runs_)[text_run_index];
page_char_index.char_index = text_run_start_indices_[text_run_index];
// Add this text run to the current static text node.
ui::AXNodeData* inline_text_box_node =
CreateInlineTextBoxNode(text_run, page_char_index);
ax_static_text_node->child_ids.push_back(inline_text_box_node->id);
ax_static_text_node->relative_bounds.bounds.Union(
inline_text_box_node->relative_bounds.bounds);
ax_name += inline_text_box_node->GetStringAttribute(
ax::mojom::StringAttribute::kName);
if (*previous_on_line_node) {
ConnectPreviousAndNextOnLine(*previous_on_line_node,
inline_text_box_node);
} else {
line_helper.StartNewLine(text_run_index);
}
line_helper.ProcessNextRun(text_run_index);
if (text_run_index < text_runs_->size() - 1) {
if (line_helper.IsRunOnSameLine(text_run_index + 1)) {
// The next run is on the same line.
*previous_on_line_node = inline_text_box_node;
} else {
// The next run is on a new line.
*previous_on_line_node = nullptr;
}
}
}
ax_node->AddStringAttribute(ax::mojom::StringAttribute::kName, ax_name);
ax_static_text_node->AddStringAttribute(ax::mojom::StringAttribute::kName,
ax_name);
}
void PdfAccessibilityTreeBuilder::AddTextToObjectNode(
size_t object_text_run_index,
uint32_t object_text_run_count,
ui::AXNodeData* object_node,
ui::AXNodeData* para_node,
ui::AXNodeData** previous_on_line_node,
size_t* text_run_index) {
// Annotation objects can overlap in PDF. There can be two overlapping
// scenarios: Partial overlap and Complete overlap.
// Partial overlap
//
// Link A starts Link B starts Link A ends Link B ends
// |a1 |b1 |a2 |b2
// -----------------------------------------------------------------------
// Text
//
// Complete overlap
// Link A starts Link B starts Link B ends Link A ends
// |a1 |b1 |b2 |a2
// -----------------------------------------------------------------------
// Text
//
// For overlapping annotations, both annotations would store the full
// text data and nothing will get truncated. For partial overlap, link `A`
// would contain text between a1 and a2 while link `B` would contain text
// between b1 and b2. For complete overlap as well, link `A` would contain
// text between a1 and a2 and link `B` would contain text between b1 and
// b2. The links would appear in the tree in the order of which they are
// present. In the tree for both overlapping scenarios, link `A` would
// appear first in the tree and link `B` after it.
// If `object_text_run_count` > 0, then the object is part of the page text.
// Make the text runs contained by the object children of the object node.
size_t end_text_run_index = object_text_run_index + object_text_run_count;
uint32_t object_end_text_run_index =
std::min(end_text_run_index, text_runs_->size()) - 1;
AddTextToAXNode(object_text_run_index, object_end_text_run_index, object_node,
previous_on_line_node);
para_node->relative_bounds.bounds.Union(object_node->relative_bounds.bounds);
*text_run_index =
NormalizeTextRunIndex(object_end_text_run_index, *text_run_index);
}
void PdfAccessibilityTreeBuilder::AddLinkToParaNode(
const chrome_pdf::AccessibilityLinkInfo& link,
ui::AXNodeData* para_node,
ui::AXNodeData** previous_on_line_node,
size_t* text_run_index) {
ui::AXNodeData* link_node = CreateLinkNode(link);
para_node->child_ids.push_back(link_node->id);
// If `link.text_range.count` == 0, then the link is not part of the page
// text. Push it ahead of the current text run.
if (link.text_range.count == 0) {
--(*text_run_index);
return;
}
// Make the text runs contained by the link children of
// the link node.
AddTextToObjectNode(link.text_range.index, link.text_range.count, link_node,
para_node, previous_on_line_node, text_run_index);
}
void PdfAccessibilityTreeBuilder::AddImageToParaNode(
const chrome_pdf::AccessibilityImageInfo& image,
ui::AXNodeData* para_node,
size_t* text_run_index) {
// If the `text_run_index` is less than or equal to the image's text run
// index, then push the image ahead of the current text run.
ui::AXNodeData* image_node = CreateImageNode(image);
para_node->child_ids.push_back(image_node->id);
--(*text_run_index);
}
void PdfAccessibilityTreeBuilder::AddHighlightToParaNode(
const chrome_pdf::AccessibilityHighlightInfo& highlight,
ui::AXNodeData* para_node,
ui::AXNodeData** previous_on_line_node,
size_t* text_run_index) {
ui::AXNodeData* highlight_node = CreateHighlightNode(highlight);
para_node->child_ids.push_back(highlight_node->id);
// Make the text runs contained by the highlight children of
// the highlight node.
AddTextToObjectNode(highlight.text_range.index, highlight.text_range.count,
highlight_node, para_node, previous_on_line_node,
text_run_index);
if (!highlight.note_text.empty()) {
ui::AXNodeData* popup_note_node = CreatePopupNoteNode(highlight);
highlight_node->child_ids.push_back(popup_note_node->id);
}
}
void PdfAccessibilityTreeBuilder::AddTextFieldToParaNode(
const chrome_pdf::AccessibilityTextFieldInfo& text_field,
ui::AXNodeData* para_node,
size_t* text_run_index) {
// If the `text_run_index` is less than or equal to the text_field's text
// run index, then push the text_field ahead of the current text run.
ui::AXNodeData* text_field_node = CreateTextFieldNode(text_field);
para_node->child_ids.push_back(text_field_node->id);
--(*text_run_index);
}
void PdfAccessibilityTreeBuilder::AddButtonToParaNode(
const chrome_pdf::AccessibilityButtonInfo& button,
ui::AXNodeData* para_node,
size_t* text_run_index) {
// If the `text_run_index` is less than or equal to the button's text
// run index, then push the button ahead of the current text run.
ui::AXNodeData* button_node = CreateButtonNode(button);
para_node->child_ids.push_back(button_node->id);
--(*text_run_index);
}
void PdfAccessibilityTreeBuilder::AddChoiceFieldToParaNode(
const chrome_pdf::AccessibilityChoiceFieldInfo& choice_field,
ui::AXNodeData* para_node,
size_t* text_run_index) {
// If the `text_run_index` is less than or equal to the choice_field's text
// run index, then push the choice_field ahead of the current text run.
ui::AXNodeData* choice_field_node = CreateChoiceFieldNode(choice_field);
para_node->child_ids.push_back(choice_field_node->id);
--(*text_run_index);
}
void PdfAccessibilityTreeBuilder::AddRemainingAnnotations(
ui::AXNodeData* para_node
#if BUILDFLAG(ENABLE_SCREEN_AI_SERVICE)
,
bool ocr_applied
#endif
) {
// If we don't have additional links, images or form fields to insert in the
// tree, then return.
if (current_link_index_ >= links_->size() &&
current_image_index_ >= images_->size() &&
current_text_field_index_ >= text_fields_->size() &&
current_button_index_ >= buttons_->size() &&
current_choice_field_index_ >= choice_fields_->size()) {
return;
}
// If we don't have a paragraph node, create a new one.
if (!para_node) {
para_node = CreateAndAppendNode(ax::mojom::Role::kParagraph,
ax::mojom::Restriction::kReadOnly);
page_node_->child_ids.push_back(para_node->id);
}
// Push all the links not anchored to any text run to the last paragraph.
for (size_t i = current_link_index_; i < links_->size(); i++) {
ui::AXNodeData* link_node = CreateLinkNode((*links_)[i]);
para_node->child_ids.push_back(link_node->id);
}
// Push all the images not anchored to any text run to the last paragraph
// unless OCR has run. PDF Searchify either OCRs all images on a page, or none
// of them.
bool push_remaining_images = true;
#if BUILDFLAG(ENABLE_SCREEN_AI_SERVICE)
push_remaining_images = !ocr_applied;
#endif
if (push_remaining_images) {
for (size_t i = current_image_index_; i < images_->size(); i++) {
const chrome_pdf::AccessibilityImageInfo& image_info = (*images_)[i];
ui::AXNodeData* image_node = CreateImageNode(image_info);
para_node->child_ids.push_back(image_node->id);
}
}
if (base::FeatureList::IsEnabled(chrome_pdf::features::kAccessiblePDFForm)) {
// Push all the text fields not anchored to any text run to the last
// paragraph.
for (size_t i = current_text_field_index_; i < text_fields_->size(); i++) {
ui::AXNodeData* text_field_node = CreateTextFieldNode((*text_fields_)[i]);
para_node->child_ids.push_back(text_field_node->id);
}
// Push all the buttons not anchored to any text run to the last
// paragraph.
for (size_t i = current_button_index_; i < buttons_->size(); i++) {
ui::AXNodeData* button_node = CreateButtonNode((*buttons_)[i]);
para_node->child_ids.push_back(button_node->id);
}
// Push all the choice fields not anchored to any text run to the last
// paragraph.
for (size_t i = current_choice_field_index_; i < choice_fields_->size();
i++) {
ui::AXNodeData* choice_field_node =
CreateChoiceFieldNode((*choice_fields_)[i]);
para_node->child_ids.push_back(choice_field_node->id);
}
}
}
} // namespace pdf
|