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chromium / chromium / src / f4abba09e5218240897a367a8f6cde39bdac16e0 / . / pdf / pdfium / pdfium_page.cc
blob: fe05918d5dafdada3e01883edf90f45787697750 [file] [log] [blame]
// Copyright 2010 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "pdf/pdfium/pdfium_page.h"
#include <math.h>
#include <stddef.h>
#include <stdint.h>
#include <algorithm>
#include <memory>
#include <utility>
#include "base/check_op.h"
#include "base/containers/span.h"
#include "base/containers/to_vector.h"
#include "base/feature_list.h"
#include "base/functional/bind.h"
#include "base/functional/callback.h"
#include "base/metrics/histogram_functions.h"
#include "base/numerics/angle_conversions.h"
#include "base/numerics/safe_math.h"
#include "base/strings/string_number_conversions.h"
#include "base/strings/string_util.h"
#include "base/strings/utf_string_conversions.h"
#include "pdf/accessibility_helper.h"
#include "pdf/accessibility_structs.h"
#include "pdf/buildflags.h"
#include "pdf/page_rotation.h"
#include "pdf/pdf_features.h"
#include "pdf/pdf_rect.h"
#include "pdf/pdfium/pdfium_api_string_buffer_adapter.h"
#include "pdf/pdfium/pdfium_api_wrappers.h"
#include "pdf/pdfium/pdfium_engine.h"
#include "pdf/pdfium/pdfium_ocr.h"
#include "pdf/pdfium/pdfium_rotation.h"
#include "pdf/pdfium/pdfium_unsupported_features.h"
#include "pdf/ui/thumbnail.h"
#include "printing/units.h"
#include "third_party/pdfium/public/cpp/fpdf_scopers.h"
#include "third_party/pdfium/public/fpdf_annot.h"
#include "third_party/pdfium/public/fpdf_catalog.h"
#include "third_party/pdfium/public/fpdf_edit.h"
#include "third_party/pdfium/public/fpdfview.h"
#include "ui/accessibility/accessibility_features.h"
#include "ui/gfx/geometry/point.h"
#include "ui/gfx/geometry/point_f.h"
#include "ui/gfx/geometry/rect.h"
#include "ui/gfx/geometry/rect_f.h"
#include "ui/gfx/geometry/size_f.h"
#include "ui/gfx/geometry/vector2d.h"
#include "ui/gfx/geometry/vector2d_f.h"
#include "ui/gfx/range/range.h"
#if BUILDFLAG(ENABLE_SCREEN_AI_SERVICE)
#include "third_party/skia/include/core/SkBitmap.h"
#endif
using printing::ConvertUnitFloat;
using printing::kPixelsPerInch;
using printing::kPointsPerInch;
namespace chrome_pdf {
namespace {
constexpr float k45DegreesInRadians = base::DegToRad(45.0f);
constexpr float k90DegreesInRadians = base::DegToRad(90.0f);
constexpr float k180DegreesInRadians = base::DegToRad(180.0f);
constexpr float k270DegreesInRadians = base::DegToRad(270.0f);
constexpr float k360DegreesInRadians = base::DegToRad(360.0f);
constexpr float kPointsToPixels = static_cast<float>(printing::kPixelsPerInch) /
static_cast<float>(printing::kPointsPerInch);
gfx::SizeF GetPageSizeInPoints(FPDF_PAGE page) {
return gfx::SizeF(FPDF_GetPageWidthF(page), FPDF_GetPageHeightF(page));
}
gfx::RectF FloatPageRectToPixelRect(FPDF_PAGE page, const gfx::RectF& input) {
int output_width = FPDF_GetPageWidthF(page);
int output_height = FPDF_GetPageHeightF(page);
int min_x;
int min_y;
int max_x;
int max_y;
if (!FPDF_PageToDevice(page, 0, 0, output_width, output_height, 0, input.x(),
input.y(), &min_x, &min_y)) {
return gfx::RectF();
}
if (!FPDF_PageToDevice(page, 0, 0, output_width, output_height, 0,
input.right(), input.bottom(), &max_x, &max_y)) {
return gfx::RectF();
}
if (max_x < min_x)
std::swap(min_x, max_x);
if (max_y < min_y)
std::swap(min_y, max_y);
// Make sure small but non-zero dimensions for `input` does not get rounded
// down to 0.
int width = max_x - min_x;
int height = max_y - min_y;
if (width == 0 && input.width())
width = 1;
if (height == 0 && input.height())
height = 1;
gfx::RectF output_rect(
ConvertUnitFloat(min_x, kPointsPerInch, kPixelsPerInch),
ConvertUnitFloat(min_y, kPointsPerInch, kPixelsPerInch),
ConvertUnitFloat(width, kPointsPerInch, kPixelsPerInch),
ConvertUnitFloat(height, kPointsPerInch, kPixelsPerInch));
return output_rect;
}
gfx::RectF GetFloatCharRectInPixels(FPDF_PAGE page,
FPDF_TEXTPAGE text_page,
int index) {
std::optional<PdfRect> char_box = GetTextCharBox(text_page, index);
if (!char_box.has_value()) {
return gfx::RectF();
}
char_box.value().Normalize();
return FloatPageRectToPixelRect(page, char_box.value().AsGfxRectF());
}
int GetFirstNonUnicodeWhiteSpaceCharIndex(FPDF_TEXTPAGE text_page,
int start_char_index,
int chars_count) {
int i = start_char_index;
while (i < chars_count &&
base::IsUnicodeWhitespace(FPDFText_GetUnicode(text_page, i))) {
i++;
}
return i;
}
AccessibilityTextDirection GetDirectionFromAngle(float angle) {
// Rotating the angle by 45 degrees to simplify the conditions statements.
// It's like if we rotated the whole cartesian coordinate system like below.
// X X
// X IV X
// X X
// X X
// X X
// III X I
// X X
// X X
// X X
// X II X
// X X
angle = fmodf(angle + k45DegreesInRadians, k360DegreesInRadians);
// Quadrant I.
if (angle >= 0 && angle <= k90DegreesInRadians)
return AccessibilityTextDirection::kLeftToRight;
// Quadrant II.
if (angle > k90DegreesInRadians && angle <= k180DegreesInRadians)
return AccessibilityTextDirection::kTopToBottom;
// Quadrant III.
if (angle > k180DegreesInRadians && angle <= k270DegreesInRadians)
return AccessibilityTextDirection::kRightToLeft;
// Quadrant IV.
return AccessibilityTextDirection::kBottomToTop;
}
void AddCharSizeToAverageCharSize(gfx::SizeF new_size,
gfx::SizeF* avg_size,
int* count) {
// Some characters sometimes have a bogus empty bounding box. We don't want
// them to impact the average.
if (!new_size.IsEmpty()) {
avg_size->set_width((avg_size->width() * *count + new_size.width()) /
(*count + 1));
avg_size->set_height((avg_size->height() * *count + new_size.height()) /
(*count + 1));
(*count)++;
}
}
float GetRotatedCharWidth(float angle, const gfx::SizeF& size) {
return fabsf(cosf(angle) * size.width()) + fabsf(sinf(angle) * size.height());
}
float GetAngleOfVector(const gfx::Vector2dF& v) {
float angle = atan2f(v.y(), v.x());
if (angle < 0)
angle += k360DegreesInRadians;
return angle;
}
float GetAngleDifference(float a, float b) {
// This is either the difference or (360 - difference).
float x = fmodf(fabsf(b - a), k360DegreesInRadians);
return x > k180DegreesInRadians ? k360DegreesInRadians - x : x;
}
bool FloatEquals(float f1, float f2) {
// The idea behind this is to use this fraction of the larger of the
// two numbers as the limit of the difference. This breaks down near
// zero, so we reuse this as the minimum absolute size we will use
// for the base of the scale too.
static constexpr float kEpsilonScale = 0.00001f;
return fabsf(f1 - f2) <
kEpsilonScale * fmaxf(fmaxf(fabsf(f1), fabsf(f2)), kEpsilonScale);
}
// Check if the smaller number is at least half the larger one. This function is
// only called on objects added by searchify.
bool FloatAtLeastHalf(float f1, float f2) {
CHECK_GT(f1, 0);
CHECK_GT(f2, 0);
float ratio = f1 < f2 ? f1 / f2 : f2 / f1;
return ratio >= 0.5f;
}
bool IsRadioButtonOrCheckBox(int button_type) {
return button_type == FPDF_FORMFIELD_CHECKBOX ||
button_type == FPDF_FORMFIELD_RADIOBUTTON;
}
template <typename T>
bool CompareTextRuns(const T& a, const T& b) {
return a.text_range.index < b.text_range.index;
}
// Set text run style information based on the `text_object` associated with a
// character of the text run.
AccessibilityTextStyleInfo CalculateTextRunStyleInfo(
FPDF_PAGEOBJECT text_object) {
AccessibilityTextStyleInfo style_info;
float font_size;
if (FPDFTextObj_GetFontSize(text_object, &font_size)) {
style_info.font_size = font_size;
}
FPDF_FONT font = FPDFTextObj_GetFont(text_object);
size_t buffer_size = FPDFFont_GetBaseFontName(font, nullptr, 0);
if (buffer_size > 0) {
PDFiumAPIStringBufferAdapter<std::string> api_string_adapter(
&style_info.font_name, buffer_size, true);
char* data = static_cast<char*>(api_string_adapter.GetData());
size_t bytes_written = FPDFFont_GetBaseFontName(font, data, buffer_size);
// Trim the null character.
api_string_adapter.Close(bytes_written);
}
// As defined in ISO 32000-1:2008, table 123.
constexpr int kFlagItalic = (1 << 6);
int font_flags = FPDFFont_GetFlags(font);
if (font_flags != -1) {
style_info.is_italic = (font_flags & kFlagItalic);
}
// Bold text is considered bold when greater than or equal to 700.
constexpr int kStandardBoldValue = 700;
int font_weight = FPDFFont_GetWeight(font);
if (font_weight != -1) {
style_info.font_weight = font_weight;
style_info.is_bold = style_info.font_weight >= kStandardBoldValue;
}
unsigned int fill_r;
unsigned int fill_g;
unsigned int fill_b;
unsigned int fill_a;
if (FPDFPageObj_GetFillColor(text_object, &fill_r, &fill_g, &fill_b,
&fill_a)) {
style_info.fill_color = MakeARGB(fill_a, fill_r, fill_g, fill_b);
} else {
style_info.fill_color = MakeARGB(0xff, 0, 0, 0);
}
unsigned int stroke_r;
unsigned int stroke_g;
unsigned int stroke_b;
unsigned int stroke_a;
if (FPDFPageObj_GetStrokeColor(text_object, &stroke_r, &stroke_g, &stroke_b,
&stroke_a)) {
style_info.stroke_color = MakeARGB(stroke_a, stroke_r, stroke_g, stroke_b);
} else {
style_info.stroke_color = MakeARGB(0xff, 0, 0, 0);
}
int render_mode = FPDFTextObj_GetTextRenderMode(text_object);
DCHECK_GE(render_mode,
static_cast<int>(AccessibilityTextRenderMode::kUnknown));
DCHECK_LE(render_mode,
static_cast<int>(AccessibilityTextRenderMode::kMaxValue));
style_info.render_mode =
static_cast<AccessibilityTextRenderMode>(render_mode);
return style_info;
}
// Returns true if the `text_object` associated with a given character has the
// same text style as the text run. `is_searchified` indicates that the text
// and style are from searchify.
bool AreTextStyleEqual(FPDF_PAGEOBJECT text_object,
const AccessibilityTextStyleInfo& style,
bool is_searchified) {
AccessibilityTextStyleInfo char_style =
CalculateTextRunStyleInfo(text_object);
// Font size of the searchify text is set based on the height of the bounding
// box around each word. Therefore the font size depends on whether that word
// has upper case or tall letters or not.
// Comparing the font size is done heuristically, as the smaller value should
// not be less than half the larger one.
// TODO(crbug.com/398064843): Add unittests with OCRed PDF data.
// TODO(crbug.com/398064843): Add block information from OCR results to
// objects and create text runs based on them.
bool font_size_match =
is_searchified ? FloatAtLeastHalf(char_style.font_size, style.font_size)
: FloatEquals(char_style.font_size, style.font_size);
return font_size_match && char_style.font_name == style.font_name &&
char_style.font_weight == style.font_weight &&
char_style.render_mode == style.render_mode &&
char_style.fill_color == style.fill_color &&
char_style.stroke_color == style.stroke_color &&
char_style.is_italic == style.is_italic &&
char_style.is_bold == style.is_bold;
}
gfx::RectF GetRotatedRectF(PageRotation rotation,
gfx::SizeF page_size,
const PdfRect& original_bounds) {
PdfRect bounds;
// When the page is rotated 90 degrees or 270 degrees, the page width and
// height are swapped. Swap it back for calculations.
if (rotation == PageRotation::kRotate90 ||
rotation == PageRotation::kRotate270) {
page_size.Transpose();
}
switch (rotation) {
case PageRotation::kRotate0: {
bounds = original_bounds;
break;
}
case PageRotation::kRotate90: {
bounds = PdfRect(
/*left=*/original_bounds.bottom(),
/*bottom=*/page_size.width() - original_bounds.right(),
/*right=*/original_bounds.top(),
/*top=*/page_size.width() - original_bounds.left());
break;
}
case PageRotation::kRotate180: {
bounds = PdfRect(
/*left=*/page_size.width() - original_bounds.right(),
/*bottom=*/page_size.height() - original_bounds.top(),
/*right=*/page_size.width() - original_bounds.left(),
/*top=*/page_size.height() - original_bounds.bottom());
break;
}
case PageRotation::kRotate270: {
bounds = PdfRect(
/*left=*/page_size.height() - original_bounds.top(),
/*bottom=*/original_bounds.left(),
/*right=*/page_size.height() - original_bounds.bottom(),
/*top=*/original_bounds.right());
break;
}
}
return bounds.AsGfxRectF();
}
// Get the effective crop box. If empty or failed to calculate the effective
// crop box, default to a `gfx::RectF` with dimensions page width by page
// height.
gfx::RectF GetEffectiveCropBox(FPDF_PAGE page,
PageRotation rotation,
const gfx::SizeF& page_size) {
gfx::RectF effective_crop_box;
const std::optional<PdfRect> maybe_crop_bounds = GetPageBoundingBox(page);
if (maybe_crop_bounds.has_value()) {
effective_crop_box =
GetRotatedRectF(rotation, page_size, maybe_crop_bounds.value());
}
if (effective_crop_box.IsEmpty()) {
effective_crop_box =
gfx::RectF(0, 0, page_size.width(), page_size.height());
}
return effective_crop_box;
}
} // namespace
PDFiumPage::LinkTarget::LinkTarget() : page(-1) {}
PDFiumPage::LinkTarget::LinkTarget(const LinkTarget& other) = default;
PDFiumPage::LinkTarget::~LinkTarget() = default;
PDFiumPage::PDFiumPage(PDFiumEngine* engine, uint32_t i)
: engine_(engine), index_(i) {}
PDFiumPage::PDFiumPage(PDFiumPage&& that) = default;
PDFiumPage::~PDFiumPage() {
DCHECK_EQ(0, preventing_unload_count_);
}
void PDFiumPage::Unload() {
// Do not unload while in the middle of a load, or if some external source
// expects `this` to stay loaded.
if (preventing_unload_count_)
return;
text_page_.reset();
if (page_) {
if (engine_->form()) {
FORM_OnBeforeClosePage(page(), engine_->form());
}
page_.reset();
}
}
FPDF_PAGE PDFiumPage::GetPage() {
ScopedUnsupportedFeature scoped_unsupported_feature(engine_);
if (!available_)
return nullptr;
if (!page_) {
ScopedUnloadPreventer scoped_unload_preventer(this);
page_.reset(FPDF_LoadPage(engine_->doc(), index_));
if (page_) {
#if BUILDFLAG(ENABLE_SCREEN_AI_SERVICE)
engine_->ScheduleSearchifyIfNeeded(this);
#endif
if (engine_->form()) {
FORM_OnAfterLoadPage(page(), engine_->form());
}
}
}
return page();
}
FPDF_TEXTPAGE PDFiumPage::GetTextPage() {
if (!available_)
return nullptr;
if (!text_page_) {
ScopedUnloadPreventer scoped_unload_preventer(this);
text_page_.reset(FPDFText_LoadPage(GetPage()));
}
return text_page();
}
void PDFiumPage::ReloadTextPage() {
CHECK_EQ(preventing_unload_count_, 0);
text_page_.reset();
GetTextPage();
}
void PDFiumPage::CalculatePageObjectTextRunBreaks() {
if (calculated_page_object_text_run_breaks_)
return;
calculated_page_object_text_run_breaks_ = true;
int chars_count = FPDFText_CountChars(GetTextPage());
if (chars_count == 0)
return;
CalculateLinks();
for (const auto& link : links_) {
if (link.start_char_index >= 0 && link.start_char_index < chars_count) {
page_object_text_run_breaks_.insert(link.start_char_index);
int next_text_run_break_index = link.start_char_index + link.char_count;
// Don't insert a break if the link is at the end of the page text.
if (next_text_run_break_index < chars_count) {
page_object_text_run_breaks_.insert(next_text_run_break_index);
}
}
}
PopulateAnnotations();
for (const auto& highlight : highlights_) {
if (highlight.start_char_index >= 0 &&
highlight.start_char_index < chars_count) {
page_object_text_run_breaks_.insert(highlight.start_char_index);
int next_text_run_break_index =
highlight.start_char_index + highlight.char_count;
// Don't insert a break if the highlight is at the end of the page text.
if (next_text_run_break_index < chars_count) {
page_object_text_run_breaks_.insert(next_text_run_break_index);
}
}
}
}
int PDFiumPage::GetCharCount() {
if (!available_) {
return 0;
}
return FPDFText_CountChars(GetTextPage());
}
std::vector<AccessibilityCharInfo> PDFiumPage::GetCharInfo() {
if (!available_) {
return {};
}
CalculateTextRuns();
const int raw_char_count = GetCharCount();
// Treat a char count of -1 (error) as 0 (an empty page), since
// other pages might have valid content.
const uint32_t char_count =
raw_char_count < 0 ? 0 : static_cast<uint32_t>(raw_char_count);
std::vector<AccessibilityCharInfo> chars(char_count);
for (uint32_t i = 0; i < char_count; ++i) {
chars[i].unicode_character = GetCharUnicode(i);
}
uint32_t char_index = 0;
for (const AccessibilityTextRunInfo& text_run : text_runs_) {
uint32_t text_run_end = char_index + text_run.len;
CHECK_LE(text_run_end, char_count);
// We need to provide enough information to draw a bounding box
// around any arbitrary text range, but the bounding boxes of characters
// we get from PDFium don't necessarily "line up".
// Example for LTR text direction: walk through the
// characters in each text run and let the width of each character be
// the difference between the x coordinate of one character and the
// x coordinate of the next. The rest of the bounds of each character
// can be computed from the bounds of the text run.
// The same idea is used for RTL, TTB and BTT text direction.
gfx::RectF char_bounds = GetCharBounds(char_index);
for (uint32_t i = char_index; i < text_run_end - 1; i++) {
CHECK_LT(i + 1, char_count);
gfx::RectF next_char_bounds = GetCharBounds(i + 1);
double& char_width = chars[i].char_width;
switch (text_run.direction) {
case AccessibilityTextDirection::kNone:
case AccessibilityTextDirection::kLeftToRight:
char_width = next_char_bounds.x() - char_bounds.x();
break;
case AccessibilityTextDirection::kTopToBottom:
char_width = next_char_bounds.y() - char_bounds.y();
break;
case AccessibilityTextDirection::kRightToLeft:
char_width = char_bounds.right() - next_char_bounds.right();
break;
case AccessibilityTextDirection::kBottomToTop:
char_width = char_bounds.bottom() - next_char_bounds.bottom();
break;
}
char_bounds = next_char_bounds;
}
double& char_width = chars[text_run_end - 1].char_width;
if (text_run.direction == AccessibilityTextDirection::kBottomToTop ||
text_run.direction == AccessibilityTextDirection::kTopToBottom) {
char_width = char_bounds.height();
} else {
char_width = char_bounds.width();
}
char_index = text_run_end;
}
return chars;
}
std::unique_ptr<AccessibilityStructureElement> PDFiumPage::GetStructureTree() {
if (!available_) {
return nullptr;
}
ScopedFPDFStructTree structure_tree(FPDF_StructTree_GetForPage(GetPage()));
if (!structure_tree) {
return nullptr;
}
auto tree_root = std::make_unique<AccessibilityStructureElement>();
tree_root->type = PdfTagType::kPart;
std::set<FPDF_STRUCTELEMENT> visited_elements;
int tree_children_count = FPDF_StructTree_CountChildren(structure_tree.get());
CHECK_GE(tree_children_count, 0);
tree_root->children.resize(tree_children_count);
for (int i = 0; i < tree_children_count; ++i) {
FPDF_STRUCTELEMENT tree_child =
FPDF_StructTree_GetChildAtIndex(structure_tree.get(), i);
tree_root->children[i] = GetStructureSubtree(tree_child, visited_elements);
if (tree_root->children[i]) {
tree_root->children[i]->parent = tree_root.get();
}
}
return tree_root;
}
std::unique_ptr<AccessibilityStructureElement> PDFiumPage::GetStructureSubtree(
FPDF_STRUCTELEMENT element,
std::set<FPDF_STRUCTELEMENT>& visited_elements) {
CHECK(element);
bool inserted = visited_elements.insert(element).second;
if (!inserted) {
return nullptr;
}
auto tree_node = std::make_unique<AccessibilityStructureElement>();
tree_node->actual_text = base::UTF16ToUTF8(CallPDFiumWideStringBufferApi(
base::BindRepeating(&FPDF_StructElement_GetActualText, element),
/*check_expected_size=*/true));
std::string alt_text = base::UTF16ToUTF8(CallPDFiumWideStringBufferApi(
base::BindRepeating(&FPDF_StructElement_GetAltText, element),
/*check_expected_size=*/true));
tree_node->alt_text = alt_text;
std::string tag_type = base::UTF16ToUTF8(CallPDFiumWideStringBufferApi(
base::BindRepeating(&FPDF_StructElement_GetType, element),
/*check_expected_size=*/true));
tree_node->type = PdfTagTypeFromString(tag_type);
tree_node->language = base::UTF16ToUTF8(CallPDFiumWideStringBufferApi(
base::BindRepeating(&FPDF_StructElement_GetLang, element),
/*check_expected_size=*/true));
if (base::FeatureList::IsEnabled(chrome_pdf::features::kPdfTags)) {
int marked_content_id = -1;
if (FPDF_StructElement_GetMarkedContentIdCount(element) > 0) {
marked_content_id =
FPDF_StructElement_GetMarkedContentIdAtIndex(element, 0);
}
if (marked_content_id >= 0) {
auto text_runs_iter =
marked_content_id_to_text_runs_map_.find(marked_content_id);
if (text_runs_iter != marked_content_id_to_text_runs_map_.end()) {
const std::vector<size_t>& text_run_indices = text_runs_iter->second;
for (size_t text_run_index : text_run_indices) {
tree_node->associated_text_runs_if_available.push_back(
&text_runs_[text_run_index]);
}
}
// TODO(crbug.com/40707542): Add `associated_image_if_available` field to
// `AccessibilityStructureElement` and populate it here by looking up
// `marked_content_id` in `marked_content_id_to_images_map_`.
}
}
int children_count = FPDF_StructElement_CountChildren(element);
CHECK_GE(children_count, 0);
tree_node->children.resize(children_count);
for (int i = 0; i < children_count; ++i) {
FPDF_STRUCTELEMENT child = FPDF_StructElement_GetChildAtIndex(element, i);
if (child) {
tree_node->children[i] = GetStructureSubtree(child, visited_elements);
if (tree_node->children[i]) {
tree_node->children[i]->parent = tree_node.get();
}
}
}
return tree_node;
}
std::optional<AccessibilityTextRunInfo> PDFiumPage::GetTextRunInfoAt(
int start_char_index) {
FPDF_PAGE page = GetPage();
FPDF_TEXTPAGE text_page = GetTextPage();
int chars_count = FPDFText_CountChars(text_page);
// Check to make sure `start_char_index` is within bounds.
if (start_char_index < 0 || start_char_index >= chars_count)
return std::nullopt;
AccessibilityTextRunInfo info;
#if BUILDFLAG(ENABLE_SCREEN_AI_SERVICE)
// This assumes all text on the page are either from the PDF itself, or from
// Searchify.
info.is_searchified = has_searchify_added_text_.value_or(false);
#endif
int actual_start_char_index = GetFirstNonUnicodeWhiteSpaceCharIndex(
text_page, start_char_index, chars_count);
// Check to see if GetFirstNonUnicodeWhiteSpaceCharIndex() iterated through
// all the characters.
if (actual_start_char_index >= chars_count) {
// If so, `info.len` needs to take the number of characters
// iterated into account.
DCHECK_GT(actual_start_char_index, start_char_index);
info.len = chars_count - start_char_index;
return info;
}
// If the first character in a text run is a space, we need to start
// `text_run_bounds` from the space character instead of the first
// non-space unicode character.
gfx::RectF text_run_bounds =
actual_start_char_index > start_char_index
? GetFloatCharRectInPixels(page, text_page, start_char_index)
: gfx::RectF();
int char_index = actual_start_char_index;
// Set text run's style info from the first character of the text run.
FPDF_PAGEOBJECT text_object = FPDFText_GetTextObject(text_page, char_index);
info.style = CalculateTextRunStyleInfo(text_object);
gfx::RectF start_char_rect =
GetFloatCharRectInPixels(page, text_page, char_index);
float text_run_font_size = info.style.font_size;
// Heuristic: Initialize the average character size to one-third of the font
// size to avoid having the first few characters misrepresent the average.
// Without it, if a text run starts with a '.', its small bounding box could
// lead to a break in the text run after only one space. Ex: ". Hello World"
// would be split in two runs: "." and "Hello World".
float font_size_minimum;
if (FPDFTextObj_GetFontSize(text_object, &font_size_minimum)) {
font_size_minimum /= 3.0f;
} else {
font_size_minimum = 0.0f;
}
gfx::SizeF avg_char_size(font_size_minimum, font_size_minimum);
int non_whitespace_chars_count = 1;
AddCharSizeToAverageCharSize(start_char_rect.size(), &avg_char_size,
&non_whitespace_chars_count);
// Add first non-space char to text run.
text_run_bounds.Union(start_char_rect);
AccessibilityTextDirection char_direction =
GetDirectionFromAngle(FPDFText_GetCharAngle(text_page, char_index));
if (char_index < chars_count)
char_index++;
gfx::RectF prev_char_rect = start_char_rect;
float estimated_font_size =
std::max(start_char_rect.width(), start_char_rect.height());
// The angle of the vector starting at the first character center-point and
// ending at the current last character center-point.
float text_run_angle = 0;
CalculatePageObjectTextRunBreaks();
const auto breakpoint_iter =
std::lower_bound(page_object_text_run_breaks_.begin(),
page_object_text_run_breaks_.end(), char_index);
int breakpoint_index = breakpoint_iter != page_object_text_run_breaks_.end()
? *breakpoint_iter
: -1;
// Searchify text uses a fixed width font with sizes selected based on the
// height of each word block. Therefore the values are not as reliable as the
// non-Searchify text and bigger threshold is used.
float character_distance_break_threshold_ratio =
info.is_searchified ? 5.0f : 2.5f;
// Continue adding characters until heuristics indicate we should end the text
// run.
while (char_index < chars_count) {
// Split a text run when it encounters a page object like links or images.
if (char_index == breakpoint_index)
break;
unsigned int character = FPDFText_GetUnicode(text_page, char_index);
gfx::RectF char_rect =
GetFloatCharRectInPixels(page, text_page, char_index);
if (!base::IsUnicodeWhitespace(character)) {
// Heuristic: End the text run if the text style of the current character
// is different from the text run's style. The style can only be different
// if the FPDF_PAGEOBJECTs are different, so check the FPDF_PAGEOBJECTs
// first to make the comparison faster.
FPDF_PAGEOBJECT current_text_object =
FPDFText_GetTextObject(text_page, char_index);
if (current_text_object != text_object &&
!AreTextStyleEqual(current_text_object, info.style,
info.is_searchified)) {
break;
}
// Heuristic: End text run if character isn't going in the same direction.
if (char_direction !=
GetDirectionFromAngle(FPDFText_GetCharAngle(text_page, char_index))) {
break;
}
// Heuristic: End the text run if the difference between the text run
// angle and the angle between the center-points of the previous and
// current characters is greater than 90 degrees.
float current_angle = GetAngleOfVector(char_rect.CenterPoint() -
prev_char_rect.CenterPoint());
if (start_char_rect != prev_char_rect) {
text_run_angle = GetAngleOfVector(prev_char_rect.CenterPoint() -
start_char_rect.CenterPoint());
if (GetAngleDifference(text_run_angle, current_angle) >
k90DegreesInRadians) {
break;
}
}
// Heuristic: End the text run if the center-point distance to the
// previous character is less than
// `character_distance_break_threshold_ratio` x the average character
// size.
AddCharSizeToAverageCharSize(char_rect.size(), &avg_char_size,
&non_whitespace_chars_count);
float avg_char_width = GetRotatedCharWidth(current_angle, avg_char_size);
float distance =
(char_rect.CenterPoint() - prev_char_rect.CenterPoint()).Length() -
GetRotatedCharWidth(current_angle, char_rect.size()) / 2 -
GetRotatedCharWidth(current_angle, prev_char_rect.size()) / 2;
if (distance >
character_distance_break_threshold_ratio * avg_char_width) {
break;
}
text_run_bounds.Union(char_rect);
prev_char_rect = char_rect;
}
if (!char_rect.IsEmpty()) {
// Update the estimated font size if needed.
float char_largest_side = std::max(char_rect.height(), char_rect.width());
estimated_font_size = std::max(char_largest_side, estimated_font_size);
}
char_index++;
}
// Some PDFs have missing or obviously bogus font sizes; substitute the
// font size by the width or height (whichever's the largest) of the bigger
// character in the current text run.
if (text_run_font_size <= 1 || text_run_font_size < estimated_font_size / 2 ||
text_run_font_size > estimated_font_size * 2) {
text_run_font_size = estimated_font_size;
}
info.len = char_index - start_char_index;
info.style.font_size = text_run_font_size;
info.bounds = text_run_bounds;
// Infer text direction from first and last character of the text run. We
// can't base our decision on the character direction, since a character of a
// RTL language will have an angle of 0 when not rotated, just like a
// character in a LTR language.
info.direction = char_index - actual_start_char_index > 1
? GetDirectionFromAngle(text_run_angle)
: AccessibilityTextDirection::kNone;
return info;
}
uint32_t PDFiumPage::GetCharUnicode(int char_index) {
// No explicit `available_` check here to return 0 when unavailable.
// If this page is unavailable, GetTextPage() returns nullptr and
// FPDFText_GetUnicode() naturally returns 0.
return FPDFText_GetUnicode(GetTextPage(), char_index);
}
gfx::RectF PDFiumPage::GetCharBounds(int char_index) {
FPDF_PAGE page = GetPage();
FPDF_TEXTPAGE text_page = GetTextPage();
return GetFloatCharRectInPixels(page, text_page, char_index);
}
gfx::RectF PDFiumPage::GetCroppedRect() {
FPDF_PAGE page = GetPage();
std::optional<PdfRect> maybe_cropped_bounds = GetPageBoundingBox(page);
if (!maybe_cropped_bounds.has_value()) {
return gfx::RectF();
}
PdfRect& cropped_bounds = maybe_cropped_bounds.value();
cropped_bounds.Normalize();
gfx::RectF rect(cropped_bounds.left(), cropped_bounds.bottom(),
cropped_bounds.width(), cropped_bounds.height());
return FloatPageRectToPixelRect(page, rect);
}
gfx::RectF PDFiumPage::GetBoundingBox() {
FPDF_PAGE page = GetPage();
std::optional<PageRotation> rotation = GetPageRotation(page);
if (!rotation.has_value()) {
return gfx::RectF();
}
// Page width and height are already swapped based on page rotation.
gfx::SizeF page_size = GetPageSizeInPoints(page);
// Start with bounds with the left and bottom values at the max possible
// bounds and the right and top values at the min possible bounds. Bounds are
// relative to the media box.
PdfRect largest_bounds(/*left=*/page_size.width(),
/*bottom=*/page_size.height(), /*right=*/0, /*top=*/0);
for (int i = 0; i < FPDFPage_CountObjects(page); ++i) {
FPDF_PAGEOBJECT page_object = FPDFPage_GetObject(page, i);
if (!page_object) {
continue;
}
const std::optional<PdfRect> maybe_bounds =
GetPageObjectBounds(page_object);
if (!maybe_bounds.has_value()) {
continue;
}
largest_bounds.Union(maybe_bounds.value());
}
for (int i = 0; i < FPDFPage_GetAnnotCount(page); ++i) {
ScopedFPDFAnnotation annotation(FPDFPage_GetAnnot(page, i));
if (!annotation) {
continue;
}
const std::optional<PdfRect> maybe_bounds = GetAnnotRect(annotation.get());
if (!maybe_bounds.has_value()) {
continue;
}
largest_bounds.Union(maybe_bounds.value());
}
gfx::RectF bounding_box =
GetRotatedRectF(rotation.value(), page_size, largest_bounds);
gfx::RectF effective_crop_box =
GetEffectiveCropBox(page, rotation.value(), page_size);
// If the bounding box is empty, default to the effective crop box.
if (bounding_box.IsEmpty()) {
bounding_box = effective_crop_box;
} else {
// Some bounding boxes may be out-of-bounds of `effective_crop_box`. Clip to
// be within `effective_crop_box`.
bounding_box.Intersect(effective_crop_box);
}
// Set the bounding box to be relative to the effective crop box.
bounding_box.set_x(bounding_box.x() - effective_crop_box.x());
bounding_box.set_y(bounding_box.y() - effective_crop_box.y());
// Scale to page pixels.
bounding_box.Scale(kPointsToPixels);
return bounding_box;
}
bool PDFiumPage::IsCharInPageBounds(int char_index,
const gfx::RectF& page_bounds) {
gfx::RectF char_bounds = GetCharBounds(char_index);
// Make sure `char_bounds` has a minimum size so Intersects() works correctly.
if (char_bounds.IsEmpty()) {
static constexpr gfx::SizeF kMinimumSize(0.0001f, 0.0001f);
char_bounds.set_size(kMinimumSize);
}
return page_bounds.Intersects(char_bounds);
}
std::vector<AccessibilityTextRunInfo> PDFiumPage::GetTextRunInfo() {
if (!available_) {
return {};
}
CalculateTextRuns();
return text_runs_;
}
std::vector<AccessibilityLinkInfo> PDFiumPage::GetLinkInfo() {
std::vector<AccessibilityLinkInfo> link_info;
if (!available_)
return link_info;
CalculateTextRuns();
CalculateLinks();
link_info.reserve(links_.size());
for (size_t i = 0; i < links_.size(); ++i) {
const Link& link = links_[i];
AccessibilityLinkInfo cur_info;
cur_info.url = link.target.url;
cur_info.index_in_page = i;
cur_info.text_range = GetEnclosingTextRunRangeForCharRange(
text_runs_, link.start_char_index, link.char_count);
gfx::Rect link_rect;
for (const auto& rect : link.bounding_rects)
link_rect.Union(rect);
cur_info.bounds = gfx::RectF(link_rect.x(), link_rect.y(),
link_rect.width(), link_rect.height());
link_info.push_back(std::move(cur_info));
}
std::sort(link_info.begin(), link_info.end(),
CompareTextRuns<AccessibilityLinkInfo>);
return link_info;
}
std::vector<AccessibilityImageInfo> PDFiumPage::GetImageInfo() {
std::vector<AccessibilityImageInfo> image_info;
if (!available_)
return image_info;
CalculateTextRuns();
CalculateImages();
image_info.reserve(images_.size());
for (const Image& image : images_) {
AccessibilityImageInfo cur_info;
cur_info.alt_text = image.alt_text;
// TODO(mohitb): Update text run index to nearest text run to image bounds.
cur_info.text_run_index = text_runs_.size();
cur_info.bounds =
gfx::RectF(image.bounding_rect.x(), image.bounding_rect.y(),
image.bounding_rect.width(), image.bounding_rect.height());
cur_info.page_object_index = image.page_object_index;
image_info.push_back(std::move(cur_info));
}
return image_info;
}
std::vector<int> PDFiumPage::GetImageObjectIndices() {
if (!available_) {
return {};
}
CalculateImages();
return base::ToVector(
images_, [](const Image& image) { return image.page_object_index; });
}
#if BUILDFLAG(ENABLE_SCREEN_AI_SERVICE)
bool PDFiumPage::HasImages() {
CalculateImages();
return images_.size();
}
SkBitmap PDFiumPage::GetImageForOcr(int page_object_index,
int max_image_dimension) {
FPDF_PAGE page = GetPage();
FPDF_PAGEOBJECT page_object = FPDFPage_GetObject(page, page_object_index);
return ::chrome_pdf::GetImageForOcr(engine_->doc(), page, page_object,
max_image_dimension);
}
void PDFiumPage::OnSearchifyGotOcrResult(bool added_text) {
CHECK(!has_searchify_added_text_.has_value());
has_searchify_added_text_ = added_text;
if (added_text) {
engine_->OnHasSearchifyText();
}
}
bool PDFiumPage::IsPageSearchified() const {
return has_searchify_added_text_.has_value();
}
bool PDFiumPage::PageCanBeUnloaded() const {
return preventing_unload_count_ == 0;
}
#endif // BUILDFLAG(ENABLE_SCREEN_AI_SERVICE)
std::vector<AccessibilityHighlightInfo> PDFiumPage::GetHighlightInfo() {
std::vector<AccessibilityHighlightInfo> highlight_info;
if (!available_)
return highlight_info;
CalculateTextRuns();
PopulateAnnotations();
highlight_info.reserve(highlights_.size());
for (size_t i = 0; i < highlights_.size(); ++i) {
const Highlight& highlight = highlights_[i];
AccessibilityHighlightInfo cur_info;
cur_info.index_in_page = i;
cur_info.text_range = GetEnclosingTextRunRangeForCharRange(
text_runs_, highlight.start_char_index, highlight.char_count);
cur_info.bounds = gfx::RectF(
highlight.bounding_rect.x(), highlight.bounding_rect.y(),
highlight.bounding_rect.width(), highlight.bounding_rect.height());
cur_info.color = highlight.color;
cur_info.note_text = highlight.note_text;
highlight_info.push_back(std::move(cur_info));
}
std::sort(highlight_info.begin(), highlight_info.end(),
CompareTextRuns<AccessibilityHighlightInfo>);
return highlight_info;
}
std::vector<AccessibilityTextFieldInfo> PDFiumPage::GetTextFieldInfo() {
std::vector<AccessibilityTextFieldInfo> text_field_info;
if (!available_)
return text_field_info;
CalculateTextRuns();
PopulateAnnotations();
text_field_info.reserve(text_fields_.size());
for (size_t i = 0; i < text_fields_.size(); ++i) {
const TextField& text_field = text_fields_[i];
AccessibilityTextFieldInfo cur_info;
cur_info.name = text_field.name;
cur_info.value = text_field.value;
cur_info.index_in_page = i;
cur_info.is_read_only = !!(text_field.flags & FPDF_FORMFLAG_READONLY);
cur_info.is_required = !!(text_field.flags & FPDF_FORMFLAG_REQUIRED);
cur_info.is_password = !!(text_field.flags & FPDF_FORMFLAG_TEXT_PASSWORD);
// TODO(crbug.com/40661774): Update text run index to nearest text run to
// text field bounds.
cur_info.text_run_index = text_runs_.size();
cur_info.bounds = gfx::RectF(
text_field.bounding_rect.x(), text_field.bounding_rect.y(),
text_field.bounding_rect.width(), text_field.bounding_rect.height());
text_field_info.push_back(std::move(cur_info));
}
return text_field_info;
}
PDFiumPage::Area PDFiumPage::GetLinkTargetAtIndex(int link_index,
LinkTarget* target) {
if (!available_ || link_index < 0)
return NONSELECTABLE_AREA;
CalculateLinks();
if (link_index >= static_cast<int>(links_.size()))
return NONSELECTABLE_AREA;
*target = links_[link_index].target;
return target->url.empty() ? DOCLINK_AREA : WEBLINK_AREA;
}
PDFiumPage::Area PDFiumPage::GetLinkTarget(FPDF_LINK link, LinkTarget* target) {
FPDF_DEST dest_link = FPDFLink_GetDest(engine_->doc(), link);
if (dest_link)
return GetDestinationTarget(dest_link, target);
FPDF_ACTION action = FPDFLink_GetAction(link);
if (!action)
return NONSELECTABLE_AREA;
switch (FPDFAction_GetType(action)) {
case PDFACTION_GOTO: {
FPDF_DEST dest_action = FPDFAction_GetDest(engine_->doc(), action);
if (dest_action)
return GetDestinationTarget(dest_action, target);
// TODO(crbug.com/40445279): We don't fully support all types of the
// in-document links.
return NONSELECTABLE_AREA;
}
case PDFACTION_URI:
return GetURITarget(action, target);
// TODO(crbug.com/40540951): Support PDFACTION_LAUNCH.
// TODO(crbug.com/40260046): Support PDFACTION_REMOTEGOTO.
case PDFACTION_LAUNCH:
case PDFACTION_REMOTEGOTO:
default:
return NONSELECTABLE_AREA;
}
}
PDFiumPage::Area PDFiumPage::GetCharInfo(const gfx::PointF& point,
int* char_index,
PdfRect* char_bounds,
int* form_type,
LinkTarget* target) {
if (!available_) {
return NONSELECTABLE_AREA;
}
// hit detection tolerance, in points.
constexpr double kTolerance = 20.0;
*char_index = FPDFText_GetCharIndexAtPos(GetTextPage(), point.x(), point.y(),
kTolerance, kTolerance);
if (*char_index >= 0) {
FPDF_BOOL rv = FPDFText_GetLooseCharBox(GetTextPage(), *char_index,
&FsRectFFromPdfRect(*char_bounds));
CHECK(rv);
}
FPDF_LINK link = FPDFLink_GetLinkAtPoint(GetPage(), point.x(), point.y());
int control = FPDFPage_HasFormFieldAtPoint(engine_->form(), GetPage(),
point.x(), point.y());
// If there is a control and link at the same point, figure out their z-order
// to determine which is on top.
if (link && control > FPDF_FORMFIELD_UNKNOWN) {
int control_z_order = FPDFPage_FormFieldZOrderAtPoint(
engine_->form(), GetPage(), point.x(), point.y());
int link_z_order =
FPDFLink_GetLinkZOrderAtPoint(GetPage(), point.x(), point.y());
DCHECK_NE(control_z_order, link_z_order);
if (control_z_order > link_z_order) {
*form_type = control;
return FormTypeToArea(*form_type);
}
// We don't handle all possible link types of the PDF. For example,
// launch actions, cross-document links, etc.
// In that case, GetLinkTarget() will return NONSELECTABLE_AREA
// and we should proceed with area detection.
Area area = GetLinkTarget(link, target);
if (area != NONSELECTABLE_AREA) {
return area;
}
} else if (link) {
// We don't handle all possible link types of the PDF. For example,
// launch actions, cross-document links, etc.
// See identical block above.
Area area = GetLinkTarget(link, target);
if (area != NONSELECTABLE_AREA) {
return area;
}
} else if (control > FPDF_FORMFIELD_UNKNOWN) {
*form_type = control;
return FormTypeToArea(*form_type);
}
if (*char_index < 0) {
return NONSELECTABLE_AREA;
}
return GetLink(*char_index, target) != -1 ? WEBLINK_AREA : TEXT_AREA;
}
// static
PDFiumPage::Area PDFiumPage::FormTypeToArea(int form_type) {
switch (form_type) {
case FPDF_FORMFIELD_COMBOBOX:
case FPDF_FORMFIELD_TEXTFIELD:
#if defined(PDF_ENABLE_XFA)
// TODO(bug_353450): figure out selection and copying for XFA fields.
case FPDF_FORMFIELD_XFA_COMBOBOX:
case FPDF_FORMFIELD_XFA_TEXTFIELD:
#endif
return FORM_TEXT_AREA;
default:
return NONSELECTABLE_AREA;
}
}
bool PDFiumPage::IsCharIndexInBounds(int index) {
return index >= 0 && index < GetCharCount();
}
PDFiumPage::Area PDFiumPage::GetDestinationTarget(FPDF_DEST destination,
LinkTarget* target) {
if (!target)
return NONSELECTABLE_AREA;
const int page_index = FPDFDest_GetDestPageIndex(engine_->doc(), destination);
if (page_index < 0)
return NONSELECTABLE_AREA;
target->page = page_index;
std::optional<float> x;
std::optional<float> y;
GetPageDestinationTarget(destination, &x, &y, &target->zoom);
// The page where a destination exists can be different from the page that it
// targets. Calculating the PDF coordinates should be based on the target
// page's size.
PDFiumPage* target_page = engine_->GetPage(target->page);
if (!target_page)
return NONSELECTABLE_AREA;
if (x) {
target->x_in_pixels =
target_page->PreProcessAndTransformInPageCoordX(x.value());
}
if (y) {
target->y_in_pixels =
target_page->PreProcessAndTransformInPageCoordY(y.value());
}
return DOCLINK_AREA;
}
void PDFiumPage::GetPageDestinationTarget(FPDF_DEST destination,
std::optional<float>* dest_x,
std::optional<float>* dest_y,
std::optional<float>* zoom_value) {
*dest_x = std::nullopt;
*dest_y = std::nullopt;
*zoom_value = std::nullopt;
if (!available_)
return;
FPDF_BOOL has_x_coord;
FPDF_BOOL has_y_coord;
FPDF_BOOL has_zoom;
FS_FLOAT x;
FS_FLOAT y;
FS_FLOAT zoom;
FPDF_BOOL success = FPDFDest_GetLocationInPage(
destination, &has_x_coord, &has_y_coord, &has_zoom, &x, &y, &zoom);
if (!success)
return;
if (has_x_coord)
*dest_x = x;
if (has_y_coord)
*dest_y = y;
if (has_zoom)
*zoom_value = zoom;
}
float PDFiumPage::PreProcessAndTransformInPageCoordX(float x) {
// If `x` < 0, scroll to the left side of the page.
// If `x` > page width, scroll to the right side of the page.
return TransformPageToScreenX(
std::clamp(x, 0.0f, FPDF_GetPageWidthF(GetPage())));
}
float PDFiumPage::PreProcessAndTransformInPageCoordY(float y) {
// If `y` < 0, it is a valid input, no extra handling is needed.
// If `y` > page height, scroll to the top of the page.
return TransformPageToScreenY(std::min(y, FPDF_GetPageHeightF(GetPage())));
}
gfx::PointF PDFiumPage::TransformPageToScreenXY(const gfx::PointF& xy) {
if (!available_)
return gfx::PointF();
gfx::RectF page_rect(xy.x(), xy.y(), 0, 0);
gfx::RectF pixel_rect(FloatPageRectToPixelRect(GetPage(), page_rect));
return gfx::PointF(pixel_rect.x(), pixel_rect.y());
}
float PDFiumPage::TransformPageToScreenX(float x) {
return TransformPageToScreenXY(gfx::PointF(x, 0)).x();
}
float PDFiumPage::TransformPageToScreenY(float y) {
return TransformPageToScreenXY(gfx::PointF(0, y)).y();
}
PDFiumPage::Area PDFiumPage::GetURITarget(FPDF_ACTION uri_action,
LinkTarget* target) const {
if (target) {
std::string url = CallPDFiumStringBufferApi(
base::BindRepeating(&FPDFAction_GetURIPath, engine_->doc(), uri_action),
/*check_expected_size=*/true);
if (!url.empty() && base::IsStringUTF8AllowingNoncharacters(url))
target->url = url;
}
return WEBLINK_AREA;
}
void PDFiumPage::CalculateTextRuns() {
if (calculated_text_runs_) {
return;
}
calculated_text_runs_ = true;
const int raw_char_count = GetCharCount();
// Treat a char count of -1 (error) as 0 (an empty page), since
// other pages might have valid content.
const uint32_t char_count =
raw_char_count < 0 ? 0 : static_cast<uint32_t>(raw_char_count);
uint32_t char_index = 0;
while (char_index < char_count) {
AccessibilityTextRunInfo text_run = GetTextRunInfoAt(char_index).value();
CHECK_LE(char_index + text_run.len, char_count);
text_runs_.push_back(text_run);
if (base::FeatureList::IsEnabled(chrome_pdf::features::kPdfTags)) {
FPDF_TEXTPAGE text_page = GetTextPage();
FPDF_PAGEOBJECT text_object =
FPDFText_GetTextObject(text_page, char_index);
int marked_content_id = FPDFPageObj_GetMarkedContentID(text_object);
if (marked_content_id >= 0) {
auto [iter, _] = marked_content_id_to_text_runs_map_.emplace(
marked_content_id, std::vector<size_t>());
CHECK_GT(text_runs_.size(), 0u);
iter->second.push_back(text_runs_.size() - 1);
}
}
char_index += text_run.len;
}
}
int PDFiumPage::GetLink(int char_index, LinkTarget* target) {
if (!available_)
return -1;
CalculateLinks();
// Get the bounding box of the rect again, since it might have moved because
// of the tolerance above.
std::optional<PdfRect> char_box = GetTextCharBox(GetTextPage(), char_index);
if (!char_box.has_value()) {
return -1;
}
gfx::Point origin = PageToScreen(gfx::Point(), /*zoom=*/1.0, char_box.value(),
PageOrientation::kOriginal)
.origin();
for (size_t i = 0; i < links_.size(); ++i) {
for (const auto& rect : links_[i].bounding_rects) {
if (rect.Contains(origin)) {
if (target)
target->url = links_[i].target.url;
return i;
}
}
}
return -1;
}
void PDFiumPage::CalculateLinks() {
if (calculated_links_)
return;
calculated_links_ = true;
PopulateWebLinks();
PopulateAnnotationLinks();
}
void PDFiumPage::PopulateWebLinks() {
ScopedFPDFPageLink links(FPDFLink_LoadWebLinks(GetTextPage()));
int count = FPDFLink_CountWebLinks(links.get());
for (int i = 0; i < count; ++i) {
// WARNING: FPDFLink_GetURL() is not compatible with
// CallPDFiumWideStringBufferApi().
std::u16string url;
int url_length = FPDFLink_GetURL(links.get(), i, nullptr, 0);
if (url_length > 0) {
PDFiumAPIStringBufferAdapter<std::u16string> api_string_adapter(
&url, url_length, true);
unsigned short* data =
reinterpret_cast<unsigned short*>(api_string_adapter.GetData());
int actual_length = FPDFLink_GetURL(links.get(), i, data, url_length);
api_string_adapter.Close(actual_length);
}
Link link;
link.target.url = base::UTF16ToUTF8(url);
if (!engine_->IsValidLink(link.target.url))
continue;
// Make sure all the characters in the URL are valid per RFC 1738.
// http://crbug.com/340326 has a sample bad PDF.
// GURL does not work correctly, e.g. it just strips \t \r \n.
bool is_invalid_url = false;
for (size_t j = 0; j < link.target.url.length(); ++j) {
// Control characters are not allowed.
// 0x7F is also a control character.
// 0x80 and above are not in US-ASCII.
if (link.target.url[j] < ' ' || link.target.url[j] >= '\x7F') {
is_invalid_url = true;
break;
}
}
if (is_invalid_url)
continue;
int rect_count = FPDFLink_CountRects(links.get(), i);
for (int j = 0; j < rect_count; ++j) {
double left;
double top;
double right;
double bottom;
if (!FPDFLink_GetRect(links.get(), i, j, &left, &top, &right, &bottom))
continue;
gfx::Rect rect = PageToScreen(gfx::Point(), 1.0, left, top, right, bottom,
PageOrientation::kOriginal);
if (rect.IsEmpty())
continue;
link.bounding_rects.push_back(rect);
}
FPDF_BOOL is_link_over_text = FPDFLink_GetTextRange(
links.get(), i, &link.start_char_index, &link.char_count);
DCHECK(is_link_over_text);
links_.push_back(link);
}
}
void PDFiumPage::PopulateAnnotationLinks() {
int start_pos = 0;
FPDF_LINK link_annot;
FPDF_PAGE page = GetPage();
while (FPDFLink_Enumerate(page, &start_pos, &link_annot)) {
Link link;
Area area = GetLinkTarget(link_annot, &link.target);
if (area == NONSELECTABLE_AREA)
continue;
PdfRect link_rect;
if (!FPDFLink_GetAnnotRect(link_annot, &FsRectFFromPdfRect(link_rect))) {
continue;
}
// The horizontal/vertical coordinates in PDF Links could be
// flipped. Swap the coordinates before further processing.
link_rect.Normalize();
int quad_point_count = FPDFLink_CountQuadPoints(link_annot);
// Calculate the bounds of link using the quad points data.
// If quad points for link is not present then use
// `link_rect` to calculate the bounds instead.
if (quad_point_count > 0) {
for (int i = 0; i < quad_point_count; ++i) {
FS_QUADPOINTSF point;
if (FPDFLink_GetQuadPoints(link_annot, i, &point)) {
// PDF Specifications: Quadpoints start from bottom left (x1, y1) and
// runs counter clockwise.
link.bounding_rects.push_back(
PageToScreen(gfx::Point(), 1.0, point.x4, point.y4, point.x2,
point.y2, PageOrientation::kOriginal));
}
}
} else {
link.bounding_rects.push_back(PageToScreen(gfx::Point(), 1.0, link_rect,
PageOrientation::kOriginal));
}
// Calculate underlying text range of link.
GetUnderlyingTextRangeForRect(
gfx::RectF(link_rect.left(), link_rect.bottom(), link_rect.width(),
link_rect.height()),
&link.start_char_index, &link.char_count);
links_.emplace_back(link);
}
}
void PDFiumPage::CalculateImages() {
if (calculated_images_)
return;
calculated_images_ = true;
FPDF_PAGE page = GetPage();
int page_object_count = FPDFPage_CountObjects(page);
for (int i = 0; i < page_object_count; ++i) {
FPDF_PAGEOBJECT page_object = FPDFPage_GetObject(page, i);
if (FPDFPageObj_GetType(page_object) != FPDF_PAGEOBJ_IMAGE) {
continue;
}
const std::optional<PdfRect> maybe_bounds =
GetPageObjectBounds(page_object);
if (!maybe_bounds.has_value()) {
continue;
}
Image image;
image.page_object_index = i;
image.bounding_rect = PageToScreen(gfx::Point(), 1.0, maybe_bounds.value(),
PageOrientation::kOriginal);
if (engine_->IsPDFDocTagged()) {
// Collect all marked content IDs for image objects so that they can
// later be used to retrieve alt text from struct tree for the page.
FPDF_IMAGEOBJ_METADATA image_metadata;
if (FPDFImageObj_GetImageMetadata(page_object, page, &image_metadata)) {
int marked_content_id = image_metadata.marked_content_id;
if (marked_content_id >= 0) {
// If `marked_content_id` is already present, ignore the one being
// inserted.
marked_content_id_to_images_map_.insert(
{marked_content_id, images_.size()});
}
}
}
images_.push_back(image);
}
}
void PDFiumPage::PopulateTextRunTypeAndImageAltText() {
CalculateTextRuns();
CalculateImages();
ScopedFPDFStructTree struct_tree(FPDF_StructTree_GetForPage(GetPage()));
if (!struct_tree) {
return;
}
if (marked_content_id_to_text_runs_map_.empty() &&
marked_content_id_to_images_map_.empty()) {
return;
}
std::set<FPDF_STRUCTELEMENT> visited_elements;
int tree_children_count = FPDF_StructTree_CountChildren(struct_tree.get());
for (int i = 0; i < tree_children_count; ++i) {
FPDF_STRUCTELEMENT current_element =
FPDF_StructTree_GetChildAtIndex(struct_tree.get(), i);
PopulateTextRunTypeAndImageAltTextForStructElement(current_element,
visited_elements);
}
}
void PDFiumPage::PopulateTextRunTypeAndImageAltTextForStructElement(
FPDF_STRUCTELEMENT current_element,
std::set<FPDF_STRUCTELEMENT>& visited_elements) {
if (!current_element) {
return;
}
bool inserted = visited_elements.insert(current_element).second;
if (!inserted) {
return;
}
int marked_content_id = -1;
if (FPDF_StructElement_GetMarkedContentIdCount(current_element)) {
marked_content_id =
FPDF_StructElement_GetMarkedContentIdAtIndex(current_element, 0);
}
if (marked_content_id >= 0) {
if (base::FeatureList::IsEnabled(chrome_pdf::features::kPdfTags)) {
auto text_runs_iter =
marked_content_id_to_text_runs_map_.find(marked_content_id);
if (text_runs_iter != marked_content_id_to_text_runs_map_.end()) {
const std::vector<size_t>& text_run_indices = text_runs_iter->second;
const std::string tag_type =
base::UTF16ToUTF8(CallPDFiumWideStringBufferApi(
base::BindRepeating(&FPDF_StructElement_GetType,
current_element),
/*check_expected_size=*/true));
for (size_t text_run_index : text_run_indices) {
CHECK_LT(text_run_index, text_runs_.size());
text_runs_[text_run_index].tag_type = tag_type;
}
}
}
auto image_iter = marked_content_id_to_images_map_.find(marked_content_id);
if (image_iter != marked_content_id_to_images_map_.end() &&
images_[image_iter->second].alt_text.empty()) {
images_[image_iter->second].alt_text =
base::UTF16ToUTF8(CallPDFiumWideStringBufferApi(
base::BindRepeating(&FPDF_StructElement_GetAltText,
current_element),
/*check_expected_size=*/true));
}
}
int children_count = FPDF_StructElement_CountChildren(current_element);
for (int i = 0; i < children_count; ++i) {
FPDF_STRUCTELEMENT child =
FPDF_StructElement_GetChildAtIndex(current_element, i);
PopulateTextRunTypeAndImageAltTextForStructElement(child, visited_elements);
}
}
void PDFiumPage::PopulateAnnotations() {
if (calculated_annotations_)
return;
FPDF_PAGE page = GetPage();
if (!page)
return;
int annotation_count = FPDFPage_GetAnnotCount(page);
for (int i = 0; i < annotation_count; ++i) {
ScopedFPDFAnnotation annot(FPDFPage_GetAnnot(page, i));
DCHECK(annot);
FPDF_ANNOTATION_SUBTYPE subtype = FPDFAnnot_GetSubtype(annot.get());
switch (subtype) {
case FPDF_ANNOT_HIGHLIGHT: {
PopulateHighlight(annot.get());
break;
}
case FPDF_ANNOT_WIDGET: {
PopulateFormField(annot.get());
break;
}
default:
break;
}
}
calculated_annotations_ = true;
}
void PDFiumPage::PopulateHighlight(FPDF_ANNOTATION annot) {
DCHECK(annot);
DCHECK_EQ(FPDFAnnot_GetSubtype(annot), FPDF_ANNOT_HIGHLIGHT);
std::optional<PdfRect> maybe_rect = GetAnnotRect(annot);
if (!maybe_rect.has_value()) {
return;
}
auto& rect = maybe_rect.value();
Highlight highlight;
// We use the bounding box of the highlight as the bounding rect.
highlight.bounding_rect =
PageToScreen(gfx::Point(), 1.0, rect, PageOrientation::kOriginal);
rect.Normalize();
GetUnderlyingTextRangeForRect(
gfx::RectF(rect.left(), rect.bottom(), rect.width(), rect.height()),
&highlight.start_char_index, &highlight.char_count);
// Retrieve the color of the highlight.
unsigned int color_r;
unsigned int color_g;
unsigned int color_b;
unsigned int color_a;
FPDF_PAGEOBJECT page_object = FPDFAnnot_GetObject(annot, 0);
if (FPDFPageObj_GetFillColor(page_object, &color_r, &color_g, &color_b,
&color_a)) {
highlight.color = MakeARGB(color_a, color_r, color_g, color_b);
} else {
// Set the same default color as in pdfium. See calls to
// GetColorStringWithDefault() in CPVT_GenerateAP::Generate*AP() in
// pdfium.
highlight.color = MakeARGB(255, 255, 255, 0);
}
// Retrieve the contents of the popup note associated with highlight. See
// table 164 in ISO 32000-1:2008 spec for more details around "Contents" key
// in a highlight annotation.
static constexpr char kContents[] = "Contents";
highlight.note_text = base::UTF16ToUTF8(CallPDFiumWideStringBufferApi(
base::BindRepeating(&FPDFAnnot_GetStringValue, annot, kContents),
/*check_expected_size=*/true));
highlights_.push_back(std::move(highlight));
}
void PDFiumPage::PopulateTextField(FPDF_ANNOTATION annot) {
DCHECK(annot);
FPDF_FORMHANDLE form_handle = engine_->form();
DCHECK_EQ(FPDFAnnot_GetFormFieldType(form_handle, annot),
FPDF_FORMFIELD_TEXTFIELD);
TextField text_field;
if (!PopulateFormFieldProperties(annot, &text_field))
return;
text_field.value = base::UTF16ToUTF8(CallPDFiumWideStringBufferApi(
base::BindRepeating(&FPDFAnnot_GetFormFieldValue, form_handle, annot),
/*check_expected_size=*/true));
text_fields_.push_back(std::move(text_field));
}
void PDFiumPage::PopulateChoiceField(FPDF_ANNOTATION annot) {
DCHECK(annot);
FPDF_FORMHANDLE form_handle = engine_->form();
int form_field_type = FPDFAnnot_GetFormFieldType(form_handle, annot);
DCHECK(form_field_type == FPDF_FORMFIELD_LISTBOX ||
form_field_type == FPDF_FORMFIELD_COMBOBOX);
ChoiceField choice_field;
if (!PopulateFormFieldProperties(annot, &choice_field))
return;
int options_count = FPDFAnnot_GetOptionCount(form_handle, annot);
if (options_count < 0)
return;
choice_field.options.resize(options_count);
for (int i = 0; i < options_count; ++i) {
choice_field.options[i].name =
base::UTF16ToUTF8(CallPDFiumWideStringBufferApi(
base::BindRepeating(&FPDFAnnot_GetOptionLabel, form_handle, annot,
i),
/*check_expected_size=*/true));
choice_field.options[i].is_selected =
FPDFAnnot_IsOptionSelected(form_handle, annot, i);
}
choice_fields_.push_back(std::move(choice_field));
}
void PDFiumPage::PopulateButton(FPDF_ANNOTATION annot) {
DCHECK(annot);
FPDF_FORMHANDLE form_handle = engine_->form();
int button_type = FPDFAnnot_GetFormFieldType(form_handle, annot);
DCHECK(button_type == FPDF_FORMFIELD_PUSHBUTTON ||
IsRadioButtonOrCheckBox(button_type));
Button button;
if (!PopulateFormFieldProperties(annot, &button))
return;
button.type = button_type;
if (IsRadioButtonOrCheckBox(button_type)) {
button.control_count = FPDFAnnot_GetFormControlCount(form_handle, annot);
if (button.control_count <= 0)
return;
button.control_index = FPDFAnnot_GetFormControlIndex(form_handle, annot);
button.value = base::UTF16ToUTF8(CallPDFiumWideStringBufferApi(
base::BindRepeating(&FPDFAnnot_GetFormFieldExportValue, form_handle,
annot),
/*check_expected_size=*/true));
button.is_checked = FPDFAnnot_IsChecked(form_handle, annot);
}
buttons_.push_back(std::move(button));
}
void PDFiumPage::PopulateFormField(FPDF_ANNOTATION annot) {
DCHECK_EQ(FPDFAnnot_GetSubtype(annot), FPDF_ANNOT_WIDGET);
int form_field_type = FPDFAnnot_GetFormFieldType(engine_->form(), annot);
// TODO(crbug.com/40661774): Populate other types of form fields too.
switch (form_field_type) {
case FPDF_FORMFIELD_PUSHBUTTON:
case FPDF_FORMFIELD_CHECKBOX:
case FPDF_FORMFIELD_RADIOBUTTON: {
PopulateButton(annot);
break;
}
case FPDF_FORMFIELD_COMBOBOX:
case FPDF_FORMFIELD_LISTBOX: {
PopulateChoiceField(annot);
break;
}
case FPDF_FORMFIELD_TEXTFIELD: {
PopulateTextField(annot);
break;
}
default:
break;
}
}
bool PDFiumPage::PopulateFormFieldProperties(FPDF_ANNOTATION annot,
FormField* form_field) {
DCHECK(annot);
const std::optional<PdfRect> maybe_rect = GetAnnotRect(annot);
if (!maybe_rect.has_value()) {
return false;
}
// We use the bounding box of the form field as the bounding rect.
form_field->bounding_rect = PageToScreen(
gfx::Point(), 1.0, maybe_rect.value(), PageOrientation::kOriginal);
FPDF_FORMHANDLE form_handle = engine_->form();
form_field->name = base::UTF16ToUTF8(CallPDFiumWideStringBufferApi(
base::BindRepeating(&FPDFAnnot_GetFormFieldName, form_handle, annot),
/*check_expected_size=*/true));
form_field->flags = FPDFAnnot_GetFormFieldFlags(form_handle, annot);
return true;
}
bool PDFiumPage::GetUnderlyingTextRangeForRect(const gfx::RectF& rect,
int* start_index,
int* char_len) {
if (!available_)
return false;
FPDF_TEXTPAGE text_page = GetTextPage();
int char_count = FPDFText_CountChars(text_page);
if (char_count <= 0)
return false;
int start_char_index = -1;
int cur_char_count = 0;
// Iterate over page text to find such continuous characters whose mid-points
// lie inside the rectangle.
for (int i = 0; i < char_count; ++i) {
std::optional<PdfRect> char_box = GetTextCharBox(text_page, i);
if (!char_box.has_value()) {
break;
}
if (rect.Contains(char_box.value().AsGfxRectF().CenterPoint())) {
if (start_char_index == -1) {
start_char_index = i;
}
++cur_char_count;
} else if (start_char_index != -1) {
break;
}
}
if (cur_char_count == 0)
return false;
*char_len = cur_char_count;
*start_index = start_char_index;
return true;
}
gfx::Rect PDFiumPage::PageToScreen(const gfx::Point& page_point,
double zoom,
const PdfRect& rect,
PageOrientation orientation) const {
return PageToScreen(page_point, zoom, rect.left(), rect.top(), rect.right(),
rect.bottom(), orientation);
}
gfx::Rect PDFiumPage::PageToScreen(const gfx::Point& page_point,
double zoom,
double left,
double top,
double right,
double bottom,
PageOrientation orientation) const {
if (!available_)
return gfx::Rect();
double start_x = (rect_.x() - page_point.x()) * zoom;
double start_y = (rect_.y() - page_point.y()) * zoom;
double size_x = rect_.width() * zoom;
double size_y = rect_.height() * zoom;
if (!base::IsValueInRangeForNumericType<int>(start_x) ||
!base::IsValueInRangeForNumericType<int>(start_y) ||
!base::IsValueInRangeForNumericType<int>(size_x) ||
!base::IsValueInRangeForNumericType<int>(size_y)) {
return gfx::Rect();
}
int new_left;
int new_top;
if (!FPDF_PageToDevice(
page(), static_cast<int>(start_x), static_cast<int>(start_y),
static_cast<int>(ceil(size_x)), static_cast<int>(ceil(size_y)),
ToPDFiumRotation(orientation), left, top, &new_left, &new_top)) {
return gfx::Rect();
}
int new_right;
int new_bottom;
if (!FPDF_PageToDevice(
page(), static_cast<int>(start_x), static_cast<int>(start_y),
static_cast<int>(ceil(size_x)), static_cast<int>(ceil(size_y)),
ToPDFiumRotation(orientation), right, bottom, &new_right,
&new_bottom)) {
return gfx::Rect();
}
// If the PDF is rotated, the horizontal/vertical coordinates could be
// flipped. See
// http://www.netl.doe.gov/publications/proceedings/03/ubc/presentations/Goeckner-pres.pdf
if (new_right < new_left)
std::swap(new_right, new_left);
if (new_bottom < new_top)
std::swap(new_bottom, new_top);
base::CheckedNumeric<int32_t> new_size_x = new_right;
new_size_x -= new_left;
new_size_x += 1;
base::CheckedNumeric<int32_t> new_size_y = new_bottom;
new_size_y -= new_top;
new_size_y += 1;
if (!new_size_x.IsValid() || !new_size_y.IsValid())
return gfx::Rect();
return gfx::Rect(new_left, new_top, new_size_x.ValueOrDie(),
new_size_y.ValueOrDie());
}
void PDFiumPage::RequestThumbnail(float device_pixel_ratio,
SendThumbnailCallback send_callback) {
DCHECK(!thumbnail_callback_);
if (available()) {
GenerateAndSendThumbnail(device_pixel_ratio, std::move(send_callback));
return;
}
// It is safe to use base::Unretained(this) because the callback is only used
// by `this`.
thumbnail_callback_ = base::BindOnce(
&PDFiumPage::GenerateAndSendThumbnail, base::Unretained(this),
device_pixel_ratio, std::move(send_callback));
}
Thumbnail PDFiumPage::GenerateThumbnail(float device_pixel_ratio) {
DCHECK(available());
FPDF_PAGE page = GetPage();
const bool has_alpha = !!FPDFPage_HasTransparency(page);
const int format = has_alpha ? FPDFBitmap_BGRA : FPDFBitmap_BGRx;
Thumbnail thumbnail(GetPageSizeInPoints(page), device_pixel_ratio);
const gfx::Size& image_size = thumbnail.image_size();
// Create and initialize the bitmap.
ScopedFPDFBitmap fpdf_bitmap(
FPDFBitmap_CreateEx(image_size.width(), image_size.height(), format,
thumbnail.GetImageData().data(), thumbnail.stride()));
const uint32_t fill_color = has_alpha ? 0x00000000 : 0xFFFFFFFF;
FPDFBitmap_FillRect(fpdf_bitmap.get(), /*left=*/0, /*top=*/0,
image_size.width(), image_size.height(), fill_color);
if (thumbnail.should_render_blank()) {
return thumbnail;
}
// The combination of the `FPDF_REVERSE_BYTE_ORDER` rendering flag and the
// `FPDFBitmap_BGRA` format when initializing `fpdf_bitmap` results in an RGBA
// rendering, which is the format required by HTML <canvas>.
constexpr int kRenderingFlags = FPDF_ANNOT | FPDF_REVERSE_BYTE_ORDER;
FPDF_RenderPageBitmap(fpdf_bitmap.get(), page, /*start_x=*/0,
/*start_y=*/0, image_size.width(), image_size.height(),
ToPDFiumRotation(PageOrientation::kOriginal),
kRenderingFlags);
// Draw the forms.
FPDF_FFLDraw(engine_->form(), fpdf_bitmap.get(), page, /*start_x=*/0,
/*start_y=*/0, image_size.width(), image_size.height(),
ToPDFiumRotation(PageOrientation::kOriginal), kRenderingFlags);
return thumbnail;
}
#if BUILDFLAG(ENABLE_PDF_INK2)
gfx::Size PDFiumPage::GetThumbnailSize(float device_pixel_ratio) {
CHECK(available());
FPDF_PAGE page = GetPage();
return Thumbnail::CalculateImageSize(GetPageSizeInPoints(page),
device_pixel_ratio);
}
#endif
void PDFiumPage::GenerateAndSendThumbnail(float device_pixel_ratio,
SendThumbnailCallback send_callback) {
std::move(send_callback).Run(GenerateThumbnail(device_pixel_ratio));
}
void PDFiumPage::MarkAvailable() {
available_ = true;
// Fulfill pending thumbnail request.
if (thumbnail_callback_)
std::move(thumbnail_callback_).Run();
}
PDFiumPage::ScopedUnloadPreventer::ScopedUnloadPreventer(PDFiumPage* page)
: page_(page) {
page_->preventing_unload_count_++;
}
PDFiumPage::ScopedUnloadPreventer::ScopedUnloadPreventer(
const ScopedUnloadPreventer& that)
: ScopedUnloadPreventer(that.page_) {}
PDFiumPage::ScopedUnloadPreventer& PDFiumPage::ScopedUnloadPreventer::operator=(
const ScopedUnloadPreventer& that) {
if (page_ != that.page_) {
page_->preventing_unload_count_--;
page_ = that.page_;
page_->preventing_unload_count_++;
}
return *this;
}
PDFiumPage::ScopedUnloadPreventer::~ScopedUnloadPreventer() {
page_->preventing_unload_count_--;
}
PDFiumPage::Link::Link() = default;
PDFiumPage::Link::Link(const Link& that) = default;
PDFiumPage::Link::~Link() = default;
PDFiumPage::Image::Image() = default;
PDFiumPage::Image::Image(const Image& that) = default;
PDFiumPage::Image::~Image() = default;
PDFiumPage::Highlight::Highlight() = default;
PDFiumPage::Highlight::Highlight(const Highlight& that) = default;
PDFiumPage::Highlight::~Highlight() = default;
PDFiumPage::FormField::FormField() = default;
PDFiumPage::FormField::FormField(const FormField& that) = default;
PDFiumPage::FormField::~FormField() = default;
PDFiumPage::TextField::TextField() = default;
PDFiumPage::TextField::TextField(const TextField& that) = default;
PDFiumPage::TextField::~TextField() = default;
PDFiumPage::ChoiceFieldOption::ChoiceFieldOption() = default;
PDFiumPage::ChoiceFieldOption::ChoiceFieldOption(
const ChoiceFieldOption& that) = default;
PDFiumPage::ChoiceFieldOption::~ChoiceFieldOption() = default;
PDFiumPage::ChoiceField::ChoiceField() = default;
PDFiumPage::ChoiceField::ChoiceField(const ChoiceField& that) = default;
PDFiumPage::ChoiceField::~ChoiceField() = default;
PDFiumPage::Button::Button() = default;
PDFiumPage::Button::Button(const Button& that) = default;
PDFiumPage::Button::~Button() = default;
} // namespace chrome_pdf