poppler-24.05.0/glib/poppler-structure-element.cc

/* poppler-structure.cc: glib interface to poppler
 *
 * Copyright (C) 2013 Igalia S.L.
 * Copyright (C) 2018 Albert Astals Cid <[email protected]>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2, or (at your option)
 * any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston, MA 02110-1301, USA.
 */

#include "config.h"

#ifndef __GI_SCANNER__
#    include <StructTreeRoot.h>
#    include <StructElement.h>
#    include <GlobalParams.h>
#    include <UnicodeMap.h>
#    include <cmath>
#endif /* !__GI_SCANNER__ */

#include "poppler.h"
#include "poppler-private.h"
#include "poppler-structure-element.h"

/**
 * SECTION:poppler-structure-element
 * @short_description: Document structure element.
 * @title: PopplerStructureElement
 *
 * Instances of #PopplerStructureElement are used to describe the structure
 * of a #PopplerDocument. To access the elements in the structure of the
 * document, use poppler_structure_element_iter_new() to obtain an iterator
 * for the top-level #PopplerStructureElement, and then use the
 * #PopplerStructureElementIter methods to traverse the structure tree.
 */

typedef struct _PopplerStructureElementClass
{
    GObjectClass parent_class;
} PopplerStructureElementClass;

G_DEFINE_TYPE(PopplerStructureElement, poppler_structure_element, G_TYPE_OBJECT)

static PopplerStructureElement *_poppler_structure_element_new(PopplerDocument *document, const StructElement *element)
{
    PopplerStructureElement *poppler_structure_element;

    g_assert(POPPLER_IS_DOCUMENT(document));
    g_assert(element);

    poppler_structure_element = (PopplerStructureElement *)g_object_new(POPPLER_TYPE_STRUCTURE_ELEMENT, nullptr, NULL);
    poppler_structure_element->document = (PopplerDocument *)g_object_ref(document);
    poppler_structure_element->elem = element;

    return poppler_structure_element;
}

static void poppler_structure_element_init(PopplerStructureElement *poppler_structure_element) { }

static void poppler_structure_element_finalize(GObject *object)
{
    PopplerStructureElement *poppler_structure_element = POPPLER_STRUCTURE_ELEMENT(object);

    /* poppler_structure_element->elem is owned by the StructTreeRoot */
    g_object_unref(poppler_structure_element->document);

    G_OBJECT_CLASS(poppler_structure_element_parent_class)->finalize(object);
}

static void poppler_structure_element_class_init(PopplerStructureElementClass *klass)
{
    GObjectClass *gobject_class = G_OBJECT_CLASS(klass);
    gobject_class->finalize = poppler_structure_element_finalize;
}

/**
 * poppler_structure_element_get_kind:
 * @poppler_structure_element: A #PopplerStructureElement
 *
 * Return value: A #PopplerStructureElementKind value.
 *
 * Since: 0.26
 */
PopplerStructureElementKind poppler_structure_element_get_kind(PopplerStructureElement *poppler_structure_element)
{
    g_return_val_if_fail(POPPLER_IS_STRUCTURE_ELEMENT(poppler_structure_element), POPPLER_STRUCTURE_ELEMENT_CONTENT);
    g_return_val_if_fail(poppler_structure_element->elem != nullptr, POPPLER_STRUCTURE_ELEMENT_CONTENT);

    switch (poppler_structure_element->elem->getType()) {
    case StructElement::MCID:
        return POPPLER_STRUCTURE_ELEMENT_CONTENT;
    case StructElement::OBJR:
        return POPPLER_STRUCTURE_ELEMENT_OBJECT_REFERENCE;
    case StructElement::Document:
        return POPPLER_STRUCTURE_ELEMENT_DOCUMENT;
    case StructElement::Part:
        return POPPLER_STRUCTURE_ELEMENT_PART;
    case StructElement::Art:
        return POPPLER_STRUCTURE_ELEMENT_ARTICLE;
    case StructElement::Sect:
        return POPPLER_STRUCTURE_ELEMENT_SECTION;
    case StructElement::Div:
        return POPPLER_STRUCTURE_ELEMENT_DIV;
    case StructElement::Span:
        return POPPLER_STRUCTURE_ELEMENT_SPAN;
    case StructElement::Quote:
        return POPPLER_STRUCTURE_ELEMENT_QUOTE;
    case StructElement::Note:
        return POPPLER_STRUCTURE_ELEMENT_NOTE;
    case StructElement::Reference:
        return POPPLER_STRUCTURE_ELEMENT_REFERENCE;
    case StructElement::BibEntry:
        return POPPLER_STRUCTURE_ELEMENT_BIBENTRY;
    case StructElement::Code:
        return POPPLER_STRUCTURE_ELEMENT_CODE;
    case StructElement::Link:
        return POPPLER_STRUCTURE_ELEMENT_LINK;
    case StructElement::Annot:
        return POPPLER_STRUCTURE_ELEMENT_ANNOT;
    case StructElement::BlockQuote:
        return POPPLER_STRUCTURE_ELEMENT_BLOCKQUOTE;
    case StructElement::Caption:
        return POPPLER_STRUCTURE_ELEMENT_CAPTION;
    case StructElement::NonStruct:
        return POPPLER_STRUCTURE_ELEMENT_NONSTRUCT;
    case StructElement::TOC:
        return POPPLER_STRUCTURE_ELEMENT_TOC;
    case StructElement::TOCI:
        return POPPLER_STRUCTURE_ELEMENT_TOC_ITEM;
    case StructElement::Index:
        return POPPLER_STRUCTURE_ELEMENT_INDEX;
    case StructElement::Private:
        return POPPLER_STRUCTURE_ELEMENT_PRIVATE;
    case StructElement::P:
        return POPPLER_STRUCTURE_ELEMENT_PARAGRAPH;
    case StructElement::H:
        return POPPLER_STRUCTURE_ELEMENT_HEADING;
    case StructElement::H1:
        return POPPLER_STRUCTURE_ELEMENT_HEADING_1;
    case StructElement::H2:
        return POPPLER_STRUCTURE_ELEMENT_HEADING_2;
    case StructElement::H3:
        return POPPLER_STRUCTURE_ELEMENT_HEADING_3;
    case StructElement::H4:
        return POPPLER_STRUCTURE_ELEMENT_HEADING_4;
    case StructElement::H5:
        return POPPLER_STRUCTURE_ELEMENT_HEADING_5;
    case StructElement::H6:
        return POPPLER_STRUCTURE_ELEMENT_HEADING_6;
    case StructElement::L:
        return POPPLER_STRUCTURE_ELEMENT_LIST;
    case StructElement::LI:
        return POPPLER_STRUCTURE_ELEMENT_LIST_ITEM;
    case StructElement::Lbl:
        return POPPLER_STRUCTURE_ELEMENT_LIST_LABEL;
    case StructElement::LBody:
        return POPPLER_STRUCTURE_ELEMENT_LIST_BODY;
    case StructElement::Table:
        return POPPLER_STRUCTURE_ELEMENT_TABLE;
    case StructElement::TR:
        return POPPLER_STRUCTURE_ELEMENT_TABLE_ROW;
    case StructElement::TH:
        return POPPLER_STRUCTURE_ELEMENT_TABLE_HEADING;
    case StructElement::TD:
        return POPPLER_STRUCTURE_ELEMENT_TABLE_DATA;
    case StructElement::THead:
        return POPPLER_STRUCTURE_ELEMENT_TABLE_HEADER;
    case StructElement::TFoot:
        return POPPLER_STRUCTURE_ELEMENT_TABLE_FOOTER;
    case StructElement::TBody:
        return POPPLER_STRUCTURE_ELEMENT_TABLE_BODY;
    case StructElement::Ruby:
        return POPPLER_STRUCTURE_ELEMENT_RUBY;
    case StructElement::RB:
        return POPPLER_STRUCTURE_ELEMENT_RUBY_BASE_TEXT;
    case StructElement::RT:
        return POPPLER_STRUCTURE_ELEMENT_RUBY_ANNOT_TEXT;
    case StructElement::RP:
        return POPPLER_STRUCTURE_ELEMENT_RUBY_PUNCTUATION;
    case StructElement::Warichu:
        return POPPLER_STRUCTURE_ELEMENT_WARICHU;
    case StructElement::WT:
        return POPPLER_STRUCTURE_ELEMENT_WARICHU_TEXT;
    case StructElement::WP:
        return POPPLER_STRUCTURE_ELEMENT_WARICHU_PUNCTUATION;
    case StructElement::Figure:
        return POPPLER_STRUCTURE_ELEMENT_FIGURE;
    case StructElement::Formula:
        return POPPLER_STRUCTURE_ELEMENT_FORMULA;
    case StructElement::Form:
        return POPPLER_STRUCTURE_ELEMENT_FORM;

    /* There should never be elements of type StructElement::Unknown */
    case StructElement::Unknown:
        g_assert_not_reached();
    }

    g_assert_not_reached();
    return POPPLER_STRUCTURE_ELEMENT_CONTENT;
}

template<typename EnumType>
struct EnumNameValue
{
    const gchar *name;
    EnumType value;

    static const EnumNameValue<EnumType> values[];
    static const Attribute::Type attribute_type;
};

#define ENUM_VALUES(E, A)                                                                                                                                                                                                                      \
    template<>                                                                                                                                                                                                                                 \
    const Attribute::Type EnumNameValue<E>::attribute_type = Attribute::A;                                                                                                                                                                     \
    template<>                                                                                                                                                                                                                                 \
    const EnumNameValue<E> EnumNameValue<E>::values[] =

ENUM_VALUES(PopplerStructurePlacement, Placement) { { "Block", POPPLER_STRUCTURE_PLACEMENT_BLOCK }, { "Inline", POPPLER_STRUCTURE_PLACEMENT_INLINE }, { "Before", POPPLER_STRUCTURE_PLACEMENT_BEFORE },
                                                    { "Start", POPPLER_STRUCTURE_PLACEMENT_START }, { "End", POPPLER_STRUCTURE_PLACEMENT_END },       {} };

ENUM_VALUES(PopplerStructureWritingMode, WritingMode) { { "LrTb", POPPLER_STRUCTURE_WRITING_MODE_LR_TB }, { "RlTb", POPPLER_STRUCTURE_WRITING_MODE_RL_TB }, { "TbRl", POPPLER_STRUCTURE_WRITING_MODE_TB_RL }, {} };

ENUM_VALUES(PopplerStructureBorderStyle, BorderStyle) { { "None", POPPLER_STRUCTURE_BORDER_STYLE_NONE },     { "Hidden", POPPLER_STRUCTURE_BORDER_STYLE_HIDDEN },
                                                        { "Dotted", POPPLER_STRUCTURE_BORDER_STYLE_DOTTED }, { "Dashed", POPPLER_STRUCTURE_BORDER_STYLE_DASHED },
                                                        { "Solid", POPPLER_STRUCTURE_BORDER_STYLE_SOLID },   { "Double", POPPLER_STRUCTURE_BORDER_STYLE_DOUBLE },
                                                        { "Groove", POPPLER_STRUCTURE_BORDER_STYLE_GROOVE }, { "Inset", POPPLER_STRUCTURE_BORDER_STYLE_INSET },
                                                        { "Outset", POPPLER_STRUCTURE_BORDER_STYLE_OUTSET }, {} };

ENUM_VALUES(PopplerStructureTextAlign,
            TextAlign) { { "Start", POPPLER_STRUCTURE_TEXT_ALIGN_START }, { "Center", POPPLER_STRUCTURE_TEXT_ALIGN_CENTER }, { "End", POPPLER_STRUCTURE_TEXT_ALIGN_END }, { "Justify", POPPLER_STRUCTURE_TEXT_ALIGN_JUSTIFY }, {} };

ENUM_VALUES(PopplerStructureBlockAlign,
            BlockAlign) { { "Before", POPPLER_STRUCTURE_BLOCK_ALIGN_BEFORE }, { "Middle", POPPLER_STRUCTURE_BLOCK_ALIGN_MIDDLE }, { "After", POPPLER_STRUCTURE_BLOCK_ALIGN_AFTER }, { "Justify", POPPLER_STRUCTURE_BLOCK_ALIGN_JUSTIFY }, {} };

ENUM_VALUES(PopplerStructureInlineAlign, InlineAlign) { { "Start", POPPLER_STRUCTURE_INLINE_ALIGN_START }, { "Center", POPPLER_STRUCTURE_INLINE_ALIGN_CENTER }, { "End", POPPLER_STRUCTURE_INLINE_ALIGN_END }, {} };

ENUM_VALUES(PopplerStructureTextDecoration, TextDecorationType) { { "None", POPPLER_STRUCTURE_TEXT_DECORATION_NONE },
                                                                  { "Underline", POPPLER_STRUCTURE_TEXT_DECORATION_UNDERLINE },
                                                                  { "Overline", POPPLER_STRUCTURE_TEXT_DECORATION_OVERLINE },
                                                                  { "LineThrough", POPPLER_STRUCTURE_TEXT_DECORATION_LINETHROUGH },
                                                                  {} };

ENUM_VALUES(PopplerStructureRubyAlign, RubyAlign) { { "Start", POPPLER_STRUCTURE_RUBY_ALIGN_START },     { "Center", POPPLER_STRUCTURE_RUBY_ALIGN_CENTER },         { "End", POPPLER_STRUCTURE_RUBY_ALIGN_END },
                                                    { "Justify", POPPLER_STRUCTURE_RUBY_ALIGN_JUSTIFY }, { "Distribute", POPPLER_STRUCTURE_RUBY_ALIGN_DISTRIBUTE }, {} };

ENUM_VALUES(PopplerStructureRubyPosition, RubyPosition) {
    { "Before", POPPLER_STRUCTURE_RUBY_POSITION_BEFORE }, { "After", POPPLER_STRUCTURE_RUBY_POSITION_AFTER }, { "Warichu", POPPLER_STRUCTURE_RUBY_POSITION_WARICHU }, { "Inline", POPPLER_STRUCTURE_RUBY_POSITION_INLINE }, {}
};

ENUM_VALUES(PopplerStructureGlyphOrientation, GlyphOrientationVertical) { { "Auto", POPPLER_STRUCTURE_GLYPH_ORIENTATION_AUTO }, { "90", POPPLER_STRUCTURE_GLYPH_ORIENTATION_90 },
                                                                          { "180", POPPLER_STRUCTURE_GLYPH_ORIENTATION_180 },   { "270", POPPLER_STRUCTURE_GLYPH_ORIENTATION_270 },
                                                                          { "360", POPPLER_STRUCTURE_GLYPH_ORIENTATION_0 },     { "-90", POPPLER_STRUCTURE_GLYPH_ORIENTATION_270 },
                                                                          { "-180", POPPLER_STRUCTURE_GLYPH_ORIENTATION_180 },  {} };

ENUM_VALUES(PopplerStructureListNumbering, ListNumbering) { { "None", POPPLER_STRUCTURE_LIST_NUMBERING_NONE },
                                                            { "Disc", POPPLER_STRUCTURE_LIST_NUMBERING_DISC },
                                                            { "Circle", POPPLER_STRUCTURE_LIST_NUMBERING_CIRCLE },
                                                            { "Square", POPPLER_STRUCTURE_LIST_NUMBERING_SQUARE },
                                                            { "Decimal", POPPLER_STRUCTURE_LIST_NUMBERING_DECIMAL },
                                                            { "UpperRoman", POPPLER_STRUCTURE_LIST_NUMBERING_UPPER_ROMAN },
                                                            { "LowerRoman", POPPLER_STRUCTURE_LIST_NUMBERING_LOWER_ROMAN },
                                                            { "UpperAlpha", POPPLER_STRUCTURE_LIST_NUMBERING_UPPER_ALPHA },
                                                            { "LowerAlpha", POPPLER_STRUCTURE_LIST_NUMBERING_LOWER_ALPHA },
                                                            {} };

ENUM_VALUES(PopplerStructureFormRole,
            Role) { { "rb", POPPLER_STRUCTURE_FORM_ROLE_RADIO_BUTTON }, { "cb", POPPLER_STRUCTURE_FORM_ROLE_CHECKBOX }, { "pb", POPPLER_STRUCTURE_FORM_ROLE_PUSH_BUTTON }, { "tv", POPPLER_STRUCTURE_FORM_ROLE_TEXT_VALUE }, {} };

ENUM_VALUES(PopplerStructureFormState, checked) { { "on", POPPLER_STRUCTURE_FORM_STATE_ON }, { "off", POPPLER_STRUCTURE_FORM_STATE_OFF }, { "neutral", POPPLER_STRUCTURE_FORM_STATE_NEUTRAL }, {} };

ENUM_VALUES(PopplerStructureTableScope, Scope) { { "Row", POPPLER_STRUCTURE_TABLE_SCOPE_ROW }, { "Column", POPPLER_STRUCTURE_TABLE_SCOPE_COLUMN }, { "Both", POPPLER_STRUCTURE_TABLE_SCOPE_BOTH }, {} };

#undef ENUM_VALUES

template<typename EnumType>
static EnumType name_to_enum(const Object *name_value)
{
    /*
     * Non-NULL names must always be valid because Poppler
     * discards the invalid attributes when parsing them.
     */
    g_assert(name_value != nullptr);

    for (const EnumNameValue<EnumType> *item = EnumNameValue<EnumType>::values; item->name; item++) {
        if (name_value->isName(item->name)) {
            return item->value;
        }
    }

    g_assert_not_reached();
    return static_cast<EnumType>(-1);
}

template<typename EnumType>
static EnumType attr_to_enum(PopplerStructureElement *poppler_structure_element)
{
    const Attribute *attr = poppler_structure_element->elem->findAttribute(EnumNameValue<EnumType>::attribute_type, true);
    return name_to_enum<EnumType>((attr != nullptr) ? attr->getValue() : Attribute::getDefaultValue(EnumNameValue<EnumType>::attribute_type));
}

static inline const Object *attr_value_or_default(PopplerStructureElement *poppler_structure_element, Attribute::Type attribute_type)
{
    const Attribute *attr = poppler_structure_element->elem->findAttribute(attribute_type, true);
    return attr ? attr->getValue() : Attribute::getDefaultValue(attribute_type);
}

/**
 * poppler_structure_element_get_page:
 * @poppler_structure_element: A #PopplerStructureElement
 *
 * Obtains the page number in which the element is contained.
 *
 * Return value: Number of the page that contains the element, of
 *    <code>-1</code> if not defined.
 *
 * Since: 0.26
 */
gint poppler_structure_element_get_page(PopplerStructureElement *poppler_structure_element)
{
    g_return_val_if_fail(POPPLER_IS_STRUCTURE_ELEMENT(poppler_structure_element), -1);
    g_return_val_if_fail(poppler_structure_element->elem != nullptr, -1);

    Ref ref;
    if (poppler_structure_element->elem->getPageRef(ref)) {
        return poppler_structure_element->document->doc->findPage(ref) - 1;
    }

    return -1;
}

/**
 * poppler_structure_element_is_content:
 * @poppler_structure_element: A #PopplerStructureElement
 *
 * Checks whether an element is actual document content.
 *
 * Return value: %TRUE if the element is content, or %FALSE otherwise.
 *
 * Since: 0.26
 */
gboolean poppler_structure_element_is_content(PopplerStructureElement *poppler_structure_element)
{
    g_return_val_if_fail(POPPLER_IS_STRUCTURE_ELEMENT(poppler_structure_element), FALSE);
    g_return_val_if_fail(poppler_structure_element->elem != nullptr, FALSE);

    return poppler_structure_element->elem->isContent();
}

/**
 * poppler_structure_element_is_inline:
 * @poppler_structure_element: A #PopplerStructureElement
 *
 * Checks whether an element is an inline element.
 *
 * Return value: %TRUE if the element is an inline element, or %FALSE otherwise.
 *
 * Since: 0.26
 */
gboolean poppler_structure_element_is_inline(PopplerStructureElement *poppler_structure_element)
{
    g_return_val_if_fail(POPPLER_IS_STRUCTURE_ELEMENT(poppler_structure_element), FALSE);
    g_return_val_if_fail(poppler_structure_element->elem != nullptr, FALSE);

    return poppler_structure_element->elem->isInline();
}

/**
 * poppler_structure_element_is_block:
 * @poppler_structure_element: A #PopplerStructureElement
 *
 * Checks whether an element is a block element.
 *
 * Return value: %TRUE if  the element is a block element, or %FALSE otherwise.
 *
 * Since: 0.26
 */
gboolean poppler_structure_element_is_block(PopplerStructureElement *poppler_structure_element)
{
    g_return_val_if_fail(POPPLER_IS_STRUCTURE_ELEMENT(poppler_structure_element), FALSE);
    g_return_val_if_fail(poppler_structure_element->elem != nullptr, FALSE);

    return poppler_structure_element->elem->isBlock();
}

/**
 * poppler_structure_element_is_grouping:
 * @poppler_structure_element: A #PopplerStructureElement
 *
 * Checks whether an element is a grouping element.
 *
 * Return value: %TRUE if the element is a grouping element, %FALSE
 *    otherwise.
 *
 * Since: 0.26
 */
gboolean poppler_structure_element_is_grouping(PopplerStructureElement *poppler_structure_element)
{
    g_return_val_if_fail(POPPLER_IS_STRUCTURE_ELEMENT(poppler_structure_element), FALSE);
    g_return_val_if_fail(poppler_structure_element->elem != nullptr, FALSE);

    return poppler_structure_element->elem->isGrouping();
}

/**
 * poppler_structure_element_get_id:
 * @poppler_structure_element: A #PopplerStructureElement
 *
 * Obtains the identifier of an element.
 *
 * Return value: (transfer full): The identifier of the element (if
 *    defined), or %NULL.
 *
 * Since: 0.26
 */
gchar *poppler_structure_element_get_id(PopplerStructureElement *poppler_structure_element)
{
    g_return_val_if_fail(POPPLER_IS_STRUCTURE_ELEMENT(poppler_structure_element), NULL);
    g_return_val_if_fail(poppler_structure_element->elem != nullptr, NULL);

    const GooString *string = poppler_structure_element->elem->getID();
    return string ? _poppler_goo_string_to_utf8(string) : nullptr;
}

/**
 * poppler_structure_element_get_title:
 * @poppler_structure_element: A #PopplerStructureElement
 *
 * Obtains the title of an element.
 *
 * Return value: (transfer full): The title of the element, or %NULL.
 *
 * Since: 0.26
 */
gchar *poppler_structure_element_get_title(PopplerStructureElement *poppler_structure_element)
{
    g_return_val_if_fail(POPPLER_IS_STRUCTURE_ELEMENT(poppler_structure_element), NULL);
    g_return_val_if_fail(poppler_structure_element->elem != nullptr, NULL);

    const GooString *string = poppler_structure_element->elem->getTitle();
    return string ? _poppler_goo_string_to_utf8(string) : nullptr;
}

/**
 * poppler_structure_element_get_abbreviation:
 * @poppler_structure_element: A #PopplerStructureElement
 *
 * Acronyms and abbreviations contained in elements of type
 * #POPPLER_STRUCTURE_ELEMENT_SPAN may have an associated expanded
 * text form, which can be retrieved using this function.
 *
 * Return value: (transfer full): Text of the expanded abbreviation if the
 *    element text is an abbreviation or acrony, %NULL if not.
 *
 * Since: 0.26
 */
gchar *poppler_structure_element_get_abbreviation(PopplerStructureElement *poppler_structure_element)
{
    g_return_val_if_fail(POPPLER_IS_STRUCTURE_ELEMENT(poppler_structure_element), NULL);
    g_return_val_if_fail(poppler_structure_element->elem != nullptr, NULL);

    if (poppler_structure_element->elem->getType() != StructElement::Span) {
        return nullptr;
    }

    const GooString *string = poppler_structure_element->elem->getExpandedAbbr();
    return string ? _poppler_goo_string_to_utf8(string) : nullptr;
}

/**
 * poppler_structure_element_get_language:
 * @poppler_structure_element: A #PopplerStructureElement
 *
 * Obtains the language and country code for the content in an element,
 * in two-letter ISO format, e.g. <code>en_ES</code>, or %NULL if not
 * defined.
 *
 * Return value: (transfer full): language and country code, or %NULL.
 *
 * Since: 0.26
 */
gchar *poppler_structure_element_get_language(PopplerStructureElement *poppler_structure_element)
{
    g_return_val_if_fail(POPPLER_IS_STRUCTURE_ELEMENT(poppler_structure_element), NULL);
    g_return_val_if_fail(poppler_structure_element->elem != nullptr, NULL);

    const GooString *string = poppler_structure_element->elem->getLanguage();
    return string ? _poppler_goo_string_to_utf8(string) : nullptr;
}

/**
 * poppler_structure_element_get_alt_text:
 * @poppler_structure_element: A #PopplerStructureElement
 *
 * Obtains the “alternate” text representation of the element (and its child
 * elements). This is mostly used for non-text elements like images and
 * figures, to specify a textual description of the element.
 *
 * Note that for elements containing proper text, the function
 * poppler_structure_element_get_text() must be used instead.
 *
 * Return value: (transfer full): The alternate text representation for the
 *    element, or %NULL if not defined.
 *
 * Since: 0.26
 */
gchar *poppler_structure_element_get_alt_text(PopplerStructureElement *poppler_structure_element)
{
    g_return_val_if_fail(POPPLER_IS_STRUCTURE_ELEMENT(poppler_structure_element), NULL);
    g_return_val_if_fail(poppler_structure_element->elem != nullptr, NULL);

    const GooString *string = poppler_structure_element->elem->getAltText();
    return string ? _poppler_goo_string_to_utf8(string) : nullptr;
}

/**
 * poppler_structure_element_get_actual_text:
 * @poppler_structure_element: A #PopplerStructureElement
 *
 * Obtains the actual text enclosed by the element (and its child elements).
 * The actual text is mostly used for non-text elements like images and
 * figures which <emphasis>do</emphasis> have the graphical appearance of text, like
 * a logo. For those the actual text is the equivalent text to those
 * graphical elements which look like text when rendered.
 *
 * Note that for elements containing proper text, the function
 * poppler_structure_element_get_text() must be used instead.
 *
 * Return value: (transfer full): The actual text for the element, or %NULL
 *    if not defined.
 *
 * Since: 0.26
 */
gchar *poppler_structure_element_get_actual_text(PopplerStructureElement *poppler_structure_element)
{
    g_return_val_if_fail(POPPLER_IS_STRUCTURE_ELEMENT(poppler_structure_element), NULL);
    g_return_val_if_fail(poppler_structure_element->elem != nullptr, NULL);

    const GooString *string = poppler_structure_element->elem->getActualText();
    return string ? _poppler_goo_string_to_utf8(string) : nullptr;
}

/**
 * poppler_structure_element_get_text:
 * @poppler_structure_element: A #PopplerStructureElement
 * @flags: A #PopplerStructureGetTextFlags value, or
 *    %POPPLER_STRUCTURE_GET_TEXT_NONE to disable all the flags.
 *
 * Obtains the text enclosed by an element, or the text enclosed by the
 * elements in the subtree (including the element itself).
 *
 * Return value: (transfer full): A string.
 *
 * Since: 0.26
 */
gchar *poppler_structure_element_get_text(PopplerStructureElement *poppler_structure_element, PopplerStructureGetTextFlags flags)
{
    g_return_val_if_fail(POPPLER_IS_STRUCTURE_ELEMENT(poppler_structure_element), NULL);
    g_return_val_if_fail(poppler_structure_element->elem != nullptr, NULL);

    GooString *string = poppler_structure_element->elem->getText(flags & POPPLER_STRUCTURE_GET_TEXT_RECURSIVE);
    gchar *result = string ? _poppler_goo_string_to_utf8(string) : nullptr;
    delete string;
    return result;
}

struct _PopplerStructureElementIter
{
    PopplerDocument *document;
    union {
        const StructElement *elem;
        const StructTreeRoot *root;
    };
    gboolean is_root;
    unsigned index;
};

G_DEFINE_BOXED_TYPE(PopplerStructureElementIter, poppler_structure_element_iter, poppler_structure_element_iter_copy, poppler_structure_element_iter_free)

/**
 * poppler_structure_element_iter_copy:
 * @iter: a #PopplerStructureElementIter
 *
 * Creates a new #PopplerStructureElementIter as a copy of @iter. The
 * returned value must be freed with poppler_structure_element_iter_free().
 *
 * Return value: (transfer full): a new #PopplerStructureElementIter
 *
 * Since: 0.26
 */
PopplerStructureElementIter *poppler_structure_element_iter_copy(PopplerStructureElementIter *iter)
{
    PopplerStructureElementIter *new_iter;

    g_return_val_if_fail(iter != nullptr, NULL);

    new_iter = g_slice_dup(PopplerStructureElementIter, iter);
    new_iter->document = (PopplerDocument *)g_object_ref(new_iter->document);

    return new_iter;
}

/**
 * poppler_structure_element_iter_free:
 * @iter: a #PopplerStructureElementIter
 *
 * Frees @iter.
 *
 * Since: 0.26
 */
void poppler_structure_element_iter_free(PopplerStructureElementIter *iter)
{
    if (G_UNLIKELY(iter == nullptr)) {
        return;
    }

    g_object_unref(iter->document);
    g_slice_free(PopplerStructureElementIter, iter);
}

/**
 * poppler_structure_element_iter_new:
 * @poppler_document: a #PopplerDocument.
 *
 * Returns the root #PopplerStructureElementIter for @document, or %NULL. The
 * returned value must be freed with poppler_structure_element_iter_free().
 *
 * Documents may have an associated structure tree &mdash;mostly, Tagged-PDF
 * compliant documents&mdash; which can be used to obtain information about
 * the document structure and its contents. Each node in the tree contains
 * a #PopplerStructureElement.
 *
 * Here is a simple example that walks the whole tree:
 *
 * <informalexample><programlisting>
 * static void
 * walk_structure (PopplerStructureElementIter *iter)
 * {
 *   do {
 *     /<!-- -->* Get the element and do something with it *<!-- -->/
 *     PopplerStructureElementIter *child = poppler_structure_element_iter_get_child (iter);
 *     if (child)
 *       walk_structure (child);
 *     poppler_structure_element_iter_free (child);
 *   } while (poppler_structure_element_iter_next (iter));
 * }
 * ...
 * {
 *   iter = poppler_structure_element_iter_new (document);
 *   walk_structure (iter);
 *   poppler_structure_element_iter_free (iter);
 * }
 * </programlisting></informalexample>
 *
 * Return value: (transfer full): a new #PopplerStructureElementIter, or %NULL if document
 *    doesn't have structure tree.
 *
 * Since: 0.26
 */
PopplerStructureElementIter *poppler_structure_element_iter_new(PopplerDocument *poppler_document)
{
    PopplerStructureElementIter *iter;

    g_return_val_if_fail(POPPLER_IS_DOCUMENT(poppler_document), NULL);

    const StructTreeRoot *root = poppler_document->doc->getStructTreeRoot();
    if (root == nullptr) {
        return nullptr;
    }

    if (root->getNumChildren() == 0) {
        return nullptr;
    }

    iter = g_slice_new0(PopplerStructureElementIter);
    iter->document = (PopplerDocument *)g_object_ref(poppler_document);
    iter->is_root = TRUE;
    iter->root = root;

    return iter;
}

/**
 * poppler_structure_element_iter_next:
 * @iter: a #PopplerStructureElementIter
 *
 * Sets @iter to point to the next structure element at the current level
 * of the tree, if valid. See poppler_structure_element_iter_new() for more
 * information.
 *
 * Return value: %TRUE, if @iter was set to the next structure element
 *
 * Since: 0.26
 */
gboolean poppler_structure_element_iter_next(PopplerStructureElementIter *iter)
{
    unsigned elements;

    g_return_val_if_fail(iter != nullptr, FALSE);

    elements = iter->is_root ? iter->root->getNumChildren() : iter->elem->getNumChildren();

    return ++iter->index < elements;
}

/**
 * poppler_structure_element_iter_get_element:
 * @iter: a #PopplerStructureElementIter
 *
 * Returns the #PopplerStructureElementIter associated with @iter.
 *
 * Return value: (transfer full): a new #PopplerStructureElementIter
 *
 * Since: 0.26
 */
PopplerStructureElement *poppler_structure_element_iter_get_element(PopplerStructureElementIter *iter)
{
    g_return_val_if_fail(iter != nullptr, NULL);

    const StructElement *elem = iter->is_root ? iter->root->getChild(iter->index) : iter->elem->getChild(iter->index);

    return _poppler_structure_element_new(iter->document, elem);
}

/**
 * poppler_structure_element_iter_get_child:
 * @parent: a #PopplerStructureElementIter
 *
 * Returns a new iterator to the children elements of the
 * #PopplerStructureElement associated with @iter. The returned value must
 * be freed with poppler_structure_element_iter_free().
 *
 * Return value: a new #PopplerStructureElementIter
 *
 * Since: 0.26
 */
PopplerStructureElementIter *poppler_structure_element_iter_get_child(PopplerStructureElementIter *parent)
{
    const StructElement *elem;

    g_return_val_if_fail(parent != nullptr, NULL);

    elem = parent->is_root ? parent->root->getChild(parent->index) : parent->elem->getChild(parent->index);

    if (elem->getNumChildren() > 0) {
        PopplerStructureElementIter *child = g_slice_new0(PopplerStructureElementIter);
        child->document = (PopplerDocument *)g_object_ref(parent->document);
        child->elem = elem;
        return child;
    }

    return nullptr;
}

struct _PopplerTextSpan
{
    gchar *text;
    gchar *font_name;
    guint flags;
    PopplerColor color;
};

G_DEFINE_BOXED_TYPE(PopplerTextSpan, poppler_text_span, poppler_text_span_copy, poppler_text_span_free)

enum
{
    POPPLER_TEXT_SPAN_FIXED_WIDTH = (1 << 0),
    POPPLER_TEXT_SPAN_SERIF = (1 << 1),
    POPPLER_TEXT_SPAN_ITALIC = (1 << 2),
    POPPLER_TEXT_SPAN_BOLD = (1 << 3),
};

static PopplerTextSpan *text_span_poppler_text_span(const TextSpan &span)
{
    PopplerTextSpan *new_span = g_slice_new0(PopplerTextSpan);
    if (GooString *text = span.getText()) {
        new_span->text = _poppler_goo_string_to_utf8(text);
    }

    new_span->color.red = colToDbl(span.getColor().r) * 65535;
    new_span->color.green = colToDbl(span.getColor().g) * 65535;
    new_span->color.blue = colToDbl(span.getColor().b) * 65535;

    if (span.getFont()) {
        // GfxFont sometimes does not have a family name but there
        // is always a font name that can be used as fallback.
        const GooString *font_name = span.getFont()->getFamily();
        if (font_name) {
            new_span->font_name = _poppler_goo_string_to_utf8(font_name);
        } else if (span.getFont()->getName()) {
            const GooString aux(*span.getFont()->getName());
            new_span->font_name = _poppler_goo_string_to_utf8(&aux);
        } else {
            new_span->font_name = nullptr;
        }

        if (span.getFont()->isFixedWidth()) {
            new_span->flags |= POPPLER_TEXT_SPAN_FIXED_WIDTH;
        }
        if (span.getFont()->isSerif()) {
            new_span->flags |= POPPLER_TEXT_SPAN_SERIF;
        }
        if (span.getFont()->isItalic()) {
            new_span->flags |= POPPLER_TEXT_SPAN_ITALIC;
        }
        if (span.getFont()->isBold()) {
            new_span->flags |= POPPLER_TEXT_SPAN_BOLD;
        }

        /* isBold() can return false for some fonts whose weight is heavy */
        switch (span.getFont()->getWeight()) {
        case GfxFont::W500:
        case GfxFont::W600:
        case GfxFont::W700:
        case GfxFont::W800:
        case GfxFont::W900:
            new_span->flags |= POPPLER_TEXT_SPAN_BOLD;
        default:
            break;
        }
    }

    return new_span;
}

/**
 * poppler_text_span_copy:
 * @poppler_text_span: a #PopplerTextSpan
 *
 * Makes a copy of a text span.
 *
 * Return value: (transfer full): A new #PopplerTextSpan
 *
 * Since: 0.26
 */
PopplerTextSpan *poppler_text_span_copy(PopplerTextSpan *poppler_text_span)
{
    PopplerTextSpan *new_span;

    g_return_val_if_fail(poppler_text_span != nullptr, NULL);

    new_span = g_slice_dup(PopplerTextSpan, poppler_text_span);
    new_span->text = g_strdup(poppler_text_span->text);
    if (poppler_text_span->font_name) {
        new_span->font_name = g_strdup(poppler_text_span->font_name);
    }
    return new_span;
}

/**
 * poppler_text_span_free:
 * @poppler_text_span: A #PopplerTextSpan
 *
 * Frees a text span.
 *
 * Since: 0.26
 */
void poppler_text_span_free(PopplerTextSpan *poppler_text_span)
{
    if (G_UNLIKELY(poppler_text_span == nullptr)) {
        return;
    }

    g_free(poppler_text_span->text);
    g_free(poppler_text_span->font_name);
    g_slice_free(PopplerTextSpan, poppler_text_span);
}

/**
 * poppler_text_span_is_fixed_width_font:
 * @poppler_text_span: a #PopplerTextSpan
 *
 * Check wether a text span is meant to be rendered using a fixed-width font.
 *
 * Return value: Whether the span uses a fixed-width font.
 *
 * Since: 0.26
 */
gboolean poppler_text_span_is_fixed_width_font(PopplerTextSpan *poppler_text_span)
{
    g_return_val_if_fail(poppler_text_span != nullptr, FALSE);

    return (poppler_text_span->flags & POPPLER_TEXT_SPAN_FIXED_WIDTH);
}

/**
 * poppler_text_span_is_serif_font:
 * @poppler_text_span: a #PopplerTextSpan
 *
 * Check whether a text span is meant to be rendered using a serif font.
 *
 * Return value: Whether the span uses a serif font.
 *
 * Since: 0.26
 */
gboolean poppler_text_span_is_serif_font(PopplerTextSpan *poppler_text_span)
{
    g_return_val_if_fail(poppler_text_span != nullptr, FALSE);

    return (poppler_text_span->flags & POPPLER_TEXT_SPAN_SERIF);
}

/**
 * poppler_text_span_is_bold_font:
 * @poppler_text_span: a #PopplerTextSpan
 *
 * Check whether a text span is meant to be rendered using a bold font.
 *
 * Return value: Whether the span uses bold font.
 *
 * Since: 0.26
 */
gboolean poppler_text_span_is_bold_font(PopplerTextSpan *poppler_text_span)
{
    g_return_val_if_fail(poppler_text_span != nullptr, FALSE);

    return (poppler_text_span->flags & POPPLER_TEXT_SPAN_BOLD);
}

/**
 * poppler_text_span_get_color:
 * @poppler_text_span: a #PopplerTextSpan
 * @color: (out): a return location for a #PopplerColor
 *
 * Obtains the color in which the text is to be rendered.
 *
 * Since: 0.26
 */
void poppler_text_span_get_color(PopplerTextSpan *poppler_text_span, PopplerColor *color)
{
    g_return_if_fail(poppler_text_span != nullptr);
    g_return_if_fail(color != nullptr);

    *color = poppler_text_span->color;
}

/**
 * poppler_text_span_get_text:
 * @poppler_text_span: a #PopplerTextSpan
 *
 * Obtains the text contained in the span.
 *
 * Return value: (transfer none): A string.
 *
 * Since: 0.26
 */
const gchar *poppler_text_span_get_text(PopplerTextSpan *poppler_text_span)
{
    g_return_val_if_fail(poppler_text_span != nullptr, NULL);

    return poppler_text_span->text;
}

/**
 * poppler_text_span_get_font_name:
 * @poppler_text_span: a #PopplerTextSpan
 *
 * Obtains the name of the font in which the span is to be rendered.
 *
 * Return value: (transfer none): A string containing the font name, or
 *   %NULL if a font is not defined.
 *
 * Since: 0.26
 */
const gchar *poppler_text_span_get_font_name(PopplerTextSpan *poppler_text_span)
{
    g_return_val_if_fail(poppler_text_span != nullptr, NULL);

    return poppler_text_span->font_name;
}

/**
 * poppler_structure_element_get_text_spans:
 * @poppler_structure_element: A #PopplerStructureElement
 * @n_text_spans: (out): A pointer to the location where the number of elements in
 *    the returned array will be stored.
 *
 * Obtains the text enclosed by an element, as an array of #PopplerTextSpan
 * structures. Each item in the list is a piece of text which share the same
 * attributes, plus its attributes. The following example shows how to
 * obtain and free the text spans of an element:
 *
 * <informalexample><programlisting>
 * guint i, n_spans;
 * PopplerTextSpan **text_spans =
 *    poppler_structure_element_get_text_spans (element, &n_spans);
 * /<!-- -->* Use the text spans *<!-- -->/
 * for (i = 0; i < n_spans; i++)
 *    poppler_text_span_free (text_spans[i]);
 * g_free (text_spans);
 * </programlisting></informalexample>
 *
 * Return value: (transfer full) (array length=n_text_spans) (element-type PopplerTextSpan):
 *    An array of #PopplerTextSpan elements.
 *
 * Since: 0.26
 */
PopplerTextSpan **poppler_structure_element_get_text_spans(PopplerStructureElement *poppler_structure_element, guint *n_text_spans)
{
    g_return_val_if_fail(POPPLER_IS_STRUCTURE_ELEMENT(poppler_structure_element), NULL);
    g_return_val_if_fail(n_text_spans != nullptr, NULL);
    g_return_val_if_fail(poppler_structure_element->elem != nullptr, NULL);

    if (!poppler_structure_element->elem->isContent()) {
        return nullptr;
    }

    const TextSpanArray spans(poppler_structure_element->elem->getTextSpans());
    PopplerTextSpan **text_spans = g_new0(PopplerTextSpan *, spans.size());

    size_t i = 0;
    for (const TextSpan &s : spans) {
        text_spans[i++] = text_span_poppler_text_span(s);
    }

    *n_text_spans = spans.size();

    return text_spans;
}

/* General Layout Attributes */

/**
 * poppler_structure_element_get_placement:
 * @poppler_structure_element: A #PopplerStructureElement
 *
 * Obtains the placement type of the structure element.
 *
 * Return value: A #PopplerStructurePlacement value.
 *
 * Since: 0.26
 */
PopplerStructurePlacement poppler_structure_element_get_placement(PopplerStructureElement *poppler_structure_element)
{
    g_return_val_if_fail(POPPLER_IS_STRUCTURE_ELEMENT(poppler_structure_element), EnumNameValue<PopplerStructurePlacement>::values[0].value);
    return attr_to_enum<PopplerStructurePlacement>(poppler_structure_element);
}

/**
 * poppler_structure_element_get_writing_mode:
 * @poppler_structure_element: A #PopplerStructureElement
 *
 * Obtains the writing mode (writing direction) of the content associated
 * with a structure element.
 *
 * Return value: A #PopplerStructureWritingMode value.
 *
 * Since: 0.26
 */
PopplerStructureWritingMode poppler_structure_element_get_writing_mode(PopplerStructureElement *poppler_structure_element)
{
    g_return_val_if_fail(POPPLER_IS_STRUCTURE_ELEMENT(poppler_structure_element), EnumNameValue<PopplerStructureWritingMode>::values[0].value);
    return attr_to_enum<PopplerStructureWritingMode>(poppler_structure_element);
}

static void convert_border_style(const Object *object, PopplerStructureBorderStyle *values)
{
    g_assert(object != nullptr);
    g_assert(values != nullptr);

    if (object->isArray()) {
        g_assert(object->arrayGetLength() == 4);
        for (guint i = 0; i < 4; i++) {
            Object item = object->arrayGet(i);
            values[i] = name_to_enum<PopplerStructureBorderStyle>(&item);
        }
    } else {
        values[0] = values[1] = values[2] = values[3] = name_to_enum<PopplerStructureBorderStyle>(object);
    }
}

/**
 * poppler_structure_element_get_border_style:
 * @poppler_structure_element: A #PopplerStructureElement
 * @border_styles: (out) (array fixed-size=4) (element-type PopplerStructureBorderStyle):
 *    An array of four #PopplerStructureBorderStyle elements.
 *
 * Obtains the border style of a structure element. The result values
 * are in before-after-start-end ordering. For example, using Western
 * left-to-right writing, that is top-bottom-left-right.
 *
 * Since: 0.26
 */
void poppler_structure_element_get_border_style(PopplerStructureElement *poppler_structure_element, PopplerStructureBorderStyle *border_styles)
{
    g_return_if_fail(POPPLER_IS_STRUCTURE_ELEMENT(poppler_structure_element));
    g_return_if_fail(border_styles != nullptr);

    convert_border_style(attr_value_or_default(poppler_structure_element, Attribute::BorderStyle), border_styles);
}

static inline void convert_doubles_array(const Object *object, gdouble **values, guint *n_values)
{
    g_assert(object->isArray());
    g_assert(n_values != nullptr);
    g_assert(values != nullptr);

    *n_values = object->arrayGetLength();
    gdouble *doubles = g_new(gdouble, *n_values);

    for (guint i = 0; i < *n_values; i++) {
        doubles[i] = object->arrayGet(i).getNum();
    }

    values = &doubles;
}

static inline void convert_color(const Object *object, PopplerColor *color)
{
    g_assert(color != nullptr);
    g_assert(object->isArray() && object->arrayGetLength() != 3);

    color->red = object->arrayGet(0).getNum() * 65535;
    color->green = object->arrayGet(1).getNum() * 65535;
    color->blue = object->arrayGet(2).getNum() * 65535;
}

/**
 * poppler_structure_element_get_color:
 * @poppler_structure_element: A #PopplerStructureElement
 * @color: (out): A #PopplerColor.
 *
 * Obtains the color of the content contained in the element.
 * If this attribute is not specified, the color for this element shall
 * be the current text fill color in effect at the start of its associated content.
 *
 * Return value: %TRUE if a color is defined for the element,
 *    %FALSE otherwise.
 *
 * Since: 0.26
 */
gboolean poppler_structure_element_get_color(PopplerStructureElement *poppler_structure_element, PopplerColor *color)
{
    g_return_val_if_fail(POPPLER_IS_STRUCTURE_ELEMENT(poppler_structure_element), FALSE);
    g_return_val_if_fail(color != nullptr, FALSE);

    const Object *value = attr_value_or_default(poppler_structure_element, Attribute::Color);
    if (value == nullptr) {
        return FALSE;
    }

    convert_color(value, color);
    return TRUE;
}

/**
 * poppler_structure_element_get_background_color:
 * @poppler_structure_element: A #PopplerStructureElement
 * @color: (out): A #PopplerColor.
 *
 * Obtains the background color of the element. If this attribute is
 * not specified, the element shall be treated as if it were transparent.
 *
 * Return value: %TRUE if a color is defined for the element,
 *    %FALSE otherwise.
 *
 * Since: 0.26
 */
gboolean poppler_structure_element_get_background_color(PopplerStructureElement *poppler_structure_element, PopplerColor *color)
{
    g_return_val_if_fail(POPPLER_IS_STRUCTURE_ELEMENT(poppler_structure_element), FALSE);
    g_return_val_if_fail(color != nullptr, FALSE);

    const Object *value = attr_value_or_default(poppler_structure_element, Attribute::BackgroundColor);
    if (value == nullptr) {
        return FALSE;
    }

    convert_color(value, color);
    return TRUE;
}

/**
 * poppler_structure_element_get_border_color:
 * @poppler_structure_element: A #PopplerStructureElement
 * @colors: (out) (array fixed-size=4) (element-type PopplerColor): An array
 *    of four #PopplerColor.
 *
 * Obtains the color of border around the element. The result values
 * are in before-after-start-end ordering (for the typical Western
 * left-to-right writing, that is top-bottom-left-right).
 * If this attribute is not specified, the border color for this element shall
 * be the current text fill color in effect at the start of its associated
 * content.
 *
 * Return value: %TRUE if a color is defined for the element,
 *    %FALSE otherwise.
 *
 * Since: 0.26
 */
gboolean poppler_structure_element_get_border_color(PopplerStructureElement *poppler_structure_element, PopplerColor *colors)
{
    g_return_val_if_fail(POPPLER_IS_STRUCTURE_ELEMENT(poppler_structure_element), FALSE);
    g_return_val_if_fail(colors != nullptr, FALSE);

    const Object *value = attr_value_or_default(poppler_structure_element, Attribute::BorderColor);
    if (value == nullptr) {
        return FALSE;
    }

    g_assert(value->isArray());
    if (value->arrayGetLength() == 4) {
        // One color per side.
        for (guint i = 0; i < 4; i++) {
            Object item = value->arrayGet(i);
            convert_color(&item, &colors[i]);
        }
    } else {
        // Same color in all sides.
        g_assert(value->arrayGetLength() == 3);
        convert_color(value, &colors[0]);
        colors[1] = colors[2] = colors[3] = colors[0];
    }

    return TRUE;
}

static inline void convert_double_or_4_doubles(const Object *object, gdouble *value)
{
    g_assert(object != nullptr);

    if (object->isArray()) {
        g_assert(object->arrayGetLength() == 4);
        for (guint i = 0; i < 4; i++) {
            value[i] = object->arrayGet(i).getNum();
        }
    } else {
        g_assert(object->isNum());
        value[0] = value[1] = value[2] = value[3] = object->getNum();
    }
}

/**
 * poppler_structure_element_get_border_thickness:
 * @poppler_structure_element: A #PopplerStructureElement
 * @border_thicknesses: (out) (array fixed-size=4) (element-type gdouble):
 *    Array with the four values of border thicknesses.
 *
 * Obtains the thickness of the border of an element. The result values
 * are in before-after-start-end ordering (for the typical Western
 * left-to-right writing, that is top-bottom-left-right).
 * A value of 0 indicates that the border shall not be drawn.
 *
 * Return value: %TRUE if the border thickness attribute is defined for
 *    the element, %FALSE otherwise.
 *
 * Since: 0.26
 */
gboolean poppler_structure_element_get_border_thickness(PopplerStructureElement *poppler_structure_element, gdouble *border_thicknesses)
{
    g_return_val_if_fail(POPPLER_IS_STRUCTURE_ELEMENT(poppler_structure_element), FALSE);
    g_return_val_if_fail(border_thicknesses != nullptr, FALSE);

    const Object *value = attr_value_or_default(poppler_structure_element, Attribute::BorderThickness);
    if (value == nullptr) {
        return FALSE;
    }

    convert_double_or_4_doubles(value, border_thicknesses);
    return TRUE;
}

/**
 * poppler_structure_element_get_padding:
 * @poppler_structure_element: A #PopplerStructureElement
 * @paddings: (out) (array fixed-size=4) (element-type gdouble):
 *    Padding for the four sides of the element.
 *
 * Obtains the padding of an element (space around it). The result
 * values are in before-after-start-end ordering. For example using
 * Western left-to-right writing, that is top-bottom-left-right.
 *
 * Since: 0.26
 */
void poppler_structure_element_get_padding(PopplerStructureElement *poppler_structure_element, gdouble *paddings)
{
    g_return_if_fail(POPPLER_IS_STRUCTURE_ELEMENT(poppler_structure_element));
    g_return_if_fail(paddings != nullptr);

    convert_double_or_4_doubles(attr_value_or_default(poppler_structure_element, Attribute::Padding), paddings);
}

/* Layout Attributes for block-level structure elements */

/**
 * poppler_structure_element_get_space_before:
 * @poppler_structure_element: A #PopplerStructureElement
 *
 * Obtains the amount of empty space before the block-level structure element.
 *
 * Return value: A positive value.
 *
 * Since: 0.26
 */
gdouble poppler_structure_element_get_space_before(PopplerStructureElement *poppler_structure_element)
{
    g_return_val_if_fail(poppler_structure_element_is_block(poppler_structure_element), NAN);
    return attr_value_or_default(poppler_structure_element, Attribute::SpaceBefore)->getNum();
}

/**
 * poppler_structure_element_get_space_after:
 * @poppler_structure_element: A #PopplerStructureElement
 *
 * Obtains the amount of empty space after the block-level structure element.
 *
 * Return value: A positive value.
 *
 * Since: 0.26
 */
gdouble poppler_structure_element_get_space_after(PopplerStructureElement *poppler_structure_element)
{
    g_return_val_if_fail(poppler_structure_element_is_block(poppler_structure_element), NAN);
    return attr_value_or_default(poppler_structure_element, Attribute::SpaceAfter)->getNum();
}

/**
 * poppler_structure_element_get_start_indent:
 * @poppler_structure_element: A #PopplerStructureElement
 *
 * Obtains the amount of indentation at the beginning of the block-level structure element.
 *
 * Return value: A numeric value.
 *
 * Since: 0.26
 */
gdouble poppler_structure_element_get_start_indent(PopplerStructureElement *poppler_structure_element)
{
    g_return_val_if_fail(poppler_structure_element_is_block(poppler_structure_element), NAN);
    return attr_value_or_default(poppler_structure_element, Attribute::StartIndent)->getNum();
}

/**
 * poppler_structure_element_get_end_indent:
 * @poppler_structure_element: A #PopplerStructureElement
 *
 * Obtains the amount of indentation at the end of the block-level structure element.
 *
 * Return value: A numeric value.
 *
 * Since: 0.26
 */
gdouble poppler_structure_element_get_end_indent(PopplerStructureElement *poppler_structure_element)
{
    g_return_val_if_fail(poppler_structure_element_is_block(poppler_structure_element), NAN);
    return attr_value_or_default(poppler_structure_element, Attribute::EndIndent)->getNum();
}

/**
 * poppler_structure_element_get_text_indent:
 * @poppler_structure_element: A #PopplerStructureElement
 *
 * Obtains the amount of indentation of the text contained in the block-level structure element.
 *
 * Return value: A numeric value.
 *
 * Since: 0.26
 */
gdouble poppler_structure_element_get_text_indent(PopplerStructureElement *poppler_structure_element)
{
    g_return_val_if_fail(poppler_structure_element_is_block(poppler_structure_element), NAN);
    return attr_value_or_default(poppler_structure_element, Attribute::TextIndent)->getNum();
}

/**
 * poppler_structure_element_get_text_align:
 * @poppler_structure_element: A #PopplerStructureElement
 *
 * Obtains the text alignment mode of the text contained into a
 * block-level structure element.
 *
 * Return value: A #PopplerStructureTextAlign value.
 *
 * Since: 0.26
 */
PopplerStructureTextAlign poppler_structure_element_get_text_align(PopplerStructureElement *poppler_structure_element)
{
    g_return_val_if_fail(poppler_structure_element_is_block(poppler_structure_element), EnumNameValue<PopplerStructureTextAlign>::values[0].value);
    return attr_to_enum<PopplerStructureTextAlign>(poppler_structure_element);
}

/**
 * poppler_structure_element_get_bounding_box:
 * @poppler_structure_element: A #PopplerStructureElement
 * @bounding_box: (out): A #PopplerRectangle.
 *
 * Obtains the size of the bounding box of a block-level structure element.
 *
 * Return value: %TRUE if a bounding box is defined for the element,
 *    %FALSE otherwise.
 *
 * Since: 0.26
 */
gboolean poppler_structure_element_get_bounding_box(PopplerStructureElement *poppler_structure_element, PopplerRectangle *bounding_box)
{
    g_return_val_if_fail(poppler_structure_element_is_block(poppler_structure_element), FALSE);
    g_return_val_if_fail(bounding_box != nullptr, FALSE);

    const Object *value = attr_value_or_default(poppler_structure_element, Attribute::BBox);
    if (value == nullptr) {
        return FALSE;
    }

    gdouble dimensions[4];
    convert_double_or_4_doubles(value, dimensions);

    bounding_box->x1 = dimensions[0];
    bounding_box->y1 = dimensions[1];
    bounding_box->x2 = dimensions[2];
    bounding_box->y2 = dimensions[3];

    return TRUE;
}

/**
 * poppler_structure_element_get_width:
 * @poppler_structure_element: A #PopplerStructureElement
 *
 * Obtains the width of the block-level structure element. Note that for elements which do
 * not specify a width, it has to be calculated, and in this case -1 is returned.
 *
 * Return value: A positive value if a width is defined, or -1
 *    if the width is to be calculated automatically.
 *
 * Since: 0.26
 */
gdouble poppler_structure_element_get_width(PopplerStructureElement *poppler_structure_element)
{
    g_return_val_if_fail(poppler_structure_element_is_block(poppler_structure_element), NAN);
    const Object *value = attr_value_or_default(poppler_structure_element, Attribute::Width);
    return value->isName("Auto") ? -1.0 : value->getNum();
}

/**
 * poppler_structure_element_get_height:
 * @poppler_structure_element: A #PopplerStructureElement
 *
 * Obtains the height of the block-level structure element. Note that for elements which do
 * not specify a height, it has to be calculated, and in this case -1 is returned.
 *
 * Return value: A positive value if a width is defined, or -1
 *    if the height is to be calculated automatically.
 *
 * Since: 0.26
 */
gdouble poppler_structure_element_get_height(PopplerStructureElement *poppler_structure_element)
{
    g_return_val_if_fail(poppler_structure_element_is_block(poppler_structure_element), NAN);
    const Object *value = attr_value_or_default(poppler_structure_element, Attribute::Height);
    return value->isName("Auto") ? -1.0 : value->getNum();
}

/**
 * poppler_structure_element_get_block_align:
 * @poppler_structure_element: A #PopplerStructureElement
 *
 * Obtains the block-alignment mode of the block-level structure element.
 *
 * Return value: A #PopplerStructureBlockAlign value.
 *
 * Since: 0.26
 */
PopplerStructureBlockAlign poppler_structure_element_get_block_align(PopplerStructureElement *poppler_structure_element)
{
    g_return_val_if_fail(poppler_structure_element_is_block(poppler_structure_element), EnumNameValue<PopplerStructureBlockAlign>::values[0].value);
    return attr_to_enum<PopplerStructureBlockAlign>(poppler_structure_element);
}

/**
 * poppler_structure_element_get_inline_align:
 * @poppler_structure_element: A #PopplerStructureElement
 *
 * Obtains the inline-alignment mode of the block-level structure element.
 *
 * Return value: A #PopplerStructureInlineAlign value.
 *
 * Since: 0.26
 */
PopplerStructureInlineAlign poppler_structure_element_get_inline_align(PopplerStructureElement *poppler_structure_element)
{
    g_return_val_if_fail(poppler_structure_element_is_block(poppler_structure_element), EnumNameValue<PopplerStructureInlineAlign>::values[0].value);
    return attr_to_enum<PopplerStructureInlineAlign>(poppler_structure_element);
}

/**
 * poppler_structure_element_get_table_border_style:
 * @poppler_structure_element: A #PopplerStructureElement
 * @border_styles: (out) (array fixed-size=4) (element-type PopplerStructureBorderStyle):
 *    An array of four #PopplerStructureBorderStyle elements.
 *
 * Obtains the table cell border style of a block-level structure element. The result values
 * are in before-after-start-end ordering. For example, using Western
 * left-to-right writing, that is top-bottom-left-right.
 *
 * Since: 0.26
 */
void poppler_structure_element_get_table_border_style(PopplerStructureElement *poppler_structure_element, PopplerStructureBorderStyle *border_styles)
{
    g_return_if_fail(poppler_structure_element_is_block(poppler_structure_element));
    g_return_if_fail(border_styles != nullptr);

    convert_border_style(attr_value_or_default(poppler_structure_element, Attribute::TBorderStyle), border_styles);
}

/**
 * poppler_structure_element_get_table_padding:
 * @poppler_structure_element: A #PopplerStructureElement
 * @paddings: (out) (array fixed-size=4) (element-type gdouble):
 *    Padding for the four sides of the element.
 *
 * Obtains the padding between the table cell’s content rectangle and the
 * surrounding border of a block-level structure element. The result
 * values are in before-after-start-end ordering (for the typical
 * Western left-to-right writing, that is top-bottom-left-right).
 *
 * Since: 0.26
 */
void poppler_structure_element_get_table_padding(PopplerStructureElement *poppler_structure_element, gdouble *paddings)
{
    g_return_if_fail(poppler_structure_element_is_block(poppler_structure_element));
    g_return_if_fail(paddings != nullptr);

    convert_double_or_4_doubles(attr_value_or_default(poppler_structure_element, Attribute::TPadding), paddings);
}

/* Layout Attributes for inline-level structure elements */

/**
 * poppler_structure_element_get_baseline_shift:
 * @poppler_structure_element: A #PopplerStructureElement
 *
 * Obtains how much the text contained in the inline-level structure element should be shifted,
 * measuring from the baseline of the glyphs.
 *
 * Return value: A numeric value.
 *
 * Since: 0.26
 */
gdouble poppler_structure_element_get_baseline_shift(PopplerStructureElement *poppler_structure_element)
{
    g_return_val_if_fail(poppler_structure_element_is_inline(poppler_structure_element), NAN);
    return attr_value_or_default(poppler_structure_element, Attribute::BaselineShift)->getNum();
}

/**
 * poppler_structure_element_get_line_height:
 * @poppler_structure_element: A #PopplerStructureElement
 *
 * Obtains the line height for the text contained in the inline-level structure element.
 * Note that for elements which do not specify a line height, it has to be calculated,
 * and in this case -1 is returned.
 *
 * Return value: A positive value if a line height is defined, or -1
 *    if the height is to be calculated automatically.
 *
 * Since: 0.26
 */
gdouble poppler_structure_element_get_line_height(PopplerStructureElement *poppler_structure_element)
{
    g_return_val_if_fail(poppler_structure_element_is_inline(poppler_structure_element), NAN);
    const Object *value = attr_value_or_default(poppler_structure_element, Attribute::LineHeight);
    return (value->isName("Normal") || value->isName("Auto")) ? -1.0 : value->getNum();
}

/**
 * poppler_structure_element_get_text_decoration_color:
 * @poppler_structure_element: A #PopplerStructureElement
 * @color: (out): A #PopplerColor.
 *
 * Obtains the color of the text decoration for the text contained
 * in the inline-level structure element.
 * If this attribute is not specified, the color for this element shall be the current fill
 * color in effect at the start of its associated content.
 *
 * Return value: %TRUE if a color is defined for the element,
 *    %FALSE otherwise.
 *
 * Since: 0.26
 */
gboolean poppler_structure_element_get_text_decoration_color(PopplerStructureElement *poppler_structure_element, PopplerColor *color)
{
    g_return_val_if_fail(poppler_structure_element_is_inline(poppler_structure_element), FALSE);
    g_return_val_if_fail(color != nullptr, FALSE);

    const Object *value = attr_value_or_default(poppler_structure_element, Attribute::TextDecorationColor);
    if (value == nullptr) {
        return FALSE;
    }

    convert_color(value, color);
    return FALSE;
}

/**
 * poppler_structure_element_get_text_decoration_thickness:
 * @poppler_structure_element: A #PopplerStructureElement
 *
 * Obtains the thickness of the text decoration for the text contained
 * in the inline-level structure element.
 * If this attribute is not specified, it shall be derived from the current
 * stroke thickness in effect at the start of the element’s associated content.
 *
 * Return value: Thickness of the text decoration, or NAN if not defined.
 *
 * Since: 0.26
 */
gdouble poppler_structure_element_get_text_decoration_thickness(PopplerStructureElement *poppler_structure_element)
{
    g_return_val_if_fail(poppler_structure_element_is_inline(poppler_structure_element), NAN);

    const Object *value = attr_value_or_default(poppler_structure_element, Attribute::TextDecorationThickness);
    return (value == nullptr) ? NAN : value->getNum();
}

/**
 * poppler_structure_element_get_text_decoration_type:
 * @poppler_structure_element: A #PopplerStructureElement
 *
 * Obtains the text decoration type of the text contained in the
 * inline-level structure element.
 *
 * Return value: A #PopplerStructureTextDecoration value.
 *
 * Since: 0.26
 */
PopplerStructureTextDecoration poppler_structure_element_get_text_decoration_type(PopplerStructureElement *poppler_structure_element)
{
    g_return_val_if_fail(poppler_structure_element_is_inline(poppler_structure_element), EnumNameValue<PopplerStructureTextDecoration>::values[0].value);
    return attr_to_enum<PopplerStructureTextDecoration>(poppler_structure_element);
}

/**
 * poppler_structure_element_get_ruby_align:
 * @poppler_structure_element: A #PopplerStructureElement
 *
 * Obtains the alignment for the ruby text contained in a
 * inline-level structure element.
 *
 * Return value: A #PopplerStructureRubyAlign value.
 *
 * Since: 0.26
 */
PopplerStructureRubyAlign poppler_structure_element_get_ruby_align(PopplerStructureElement *poppler_structure_element)
{
    g_return_val_if_fail(poppler_structure_element_is_inline(poppler_structure_element), EnumNameValue<PopplerStructureRubyAlign>::values[0].value);
    return attr_to_enum<PopplerStructureRubyAlign>(poppler_structure_element);
}

/**
 * poppler_structure_element_get_ruby_position:
 * @poppler_structure_element: A #PopplerStructureElement
 *
 * Obtains the position for the ruby text contained in a
 * inline-level structure element.
 *
 * Return value: A #PopplerStructureRubyPosition value.
 *
 * Since: 0.26
 */
PopplerStructureRubyPosition poppler_structure_element_get_ruby_position(PopplerStructureElement *poppler_structure_element)
{
    g_return_val_if_fail(poppler_structure_element_is_inline(poppler_structure_element), EnumNameValue<PopplerStructureRubyPosition>::values[0].value);
    return attr_to_enum<PopplerStructureRubyPosition>(poppler_structure_element);
}

/**
 * poppler_structure_element_get_glyph_orientation:
 * @poppler_structure_element: A #PopplerStructureElement
 *
 * Obtains the glyph orientation for the text contained in a
 * inline-level structure element.
 *
 * Return value: A #PopplerStructureGlyphOrientation value.
 *
 * Since: 0.26
 */
PopplerStructureGlyphOrientation poppler_structure_element_get_glyph_orientation(PopplerStructureElement *poppler_structure_element)
{
    g_return_val_if_fail(poppler_structure_element_is_inline(poppler_structure_element), EnumNameValue<PopplerStructureGlyphOrientation>::values[0].value);
    return attr_to_enum<PopplerStructureGlyphOrientation>(poppler_structure_element);
}

/* Column Attributes */

/**
 * poppler_structure_element_get_column_count:
 * @poppler_structure_element: A #PopplerStructureElement
 *
 * Obtains the number of columns used to lay out the content contained
 * in the grouping element.
 *
 * Return value: Number of columns.
 *
 * Since: 0.26
 */
guint poppler_structure_element_get_column_count(PopplerStructureElement *poppler_structure_element)
{
    g_return_val_if_fail(poppler_structure_element_is_grouping(poppler_structure_element), 0);
    return static_cast<guint>(attr_value_or_default(poppler_structure_element, Attribute::ColumnCount)->getInt());
}

/**
 * poppler_structure_element_get_column_gaps:
 * @poppler_structure_element: A #PopplerStructureElement
 * @n_values: (out): Size of the returned array.
 *
 * Obtains the size of the gaps in between adjacent columns. Returns an
 * array of elements: the first one is the size of the gap in between
 * columns 1 and 2, second is the size between columns 2 and 3, and so on.
 *
 * For elements which use a single column, %NULL is returned and @n_values
 * is set to zero.
 *
 * If the attribute is undefined, %NULL is returned and @n_values is set
 * to a non-zero value.
 *
 * The array with the results is allocated by the function. When it is
 * not needed anymore, be sure to call g_free() on it.
 *
 * Return value: (transfer full) (array length=n_values) (element-type gdouble):
 *    Array containing the values for the column gaps, or %NULL if the
 *    array is empty or the attribute is not defined.
 *
 * Since: 0.26
 */
gdouble *poppler_structure_element_get_column_gaps(PopplerStructureElement *poppler_structure_element, guint *n_values)
{
    g_return_val_if_fail(poppler_structure_element_is_grouping(poppler_structure_element), NULL);
    g_return_val_if_fail(n_values != nullptr, NULL);

    const Object *value = attr_value_or_default(poppler_structure_element, Attribute::ColumnGap);
    if (value == nullptr) {
        *n_values = static_cast<guint>(-1);
        return nullptr;
    }

    gdouble *result = nullptr;
    convert_doubles_array(value, &result, n_values);
    return result;
}

/**
 * poppler_structure_element_get_column_widths:
 * @poppler_structure_element: A #PopplerStructureElement
 * @n_values: (out): Size of the returned array.
 *
 * Obtains an array with the widths of the columns.
 *
 * The array with the results is allocated by the function. When it is
 * not needed anymore, be sure to call g_free() on it.
 *
 * Return value: (transfer full) (array length=n_values) (element-type gdouble):
 *    Array containing widths of the columns, or %NULL if the attribute
 *    is not defined.
 *
 * Since: 0.26
 */
gdouble *poppler_structure_element_get_column_widths(PopplerStructureElement *poppler_structure_element, guint *n_values)
{
    g_return_val_if_fail(poppler_structure_element_is_grouping(poppler_structure_element), NULL);
    g_return_val_if_fail(n_values != nullptr, NULL);

    const Object *value = attr_value_or_default(poppler_structure_element, Attribute::ColumnWidths);
    if (value == nullptr) {
        return nullptr;
    }

    gdouble *result = nullptr;
    convert_doubles_array(value, &result, n_values);
    return result;
}

/* List Attribute */

/**
 * poppler_structure_element_get_list_numbering:
 * @poppler_structure_element: A #PopplerStructureElement
 *
 * Obtains the list numbering style for list items.
 *
 * Return value: A #PopplerStructureListNumbering value.
 *
 * Since: 0.26
 */
PopplerStructureListNumbering poppler_structure_element_get_list_numbering(PopplerStructureElement *poppler_structure_element)
{
    g_return_val_if_fail(poppler_structure_element_get_kind(poppler_structure_element) == POPPLER_STRUCTURE_ELEMENT_LIST_ITEM, EnumNameValue<PopplerStructureListNumbering>::values[0].value);
    return attr_to_enum<PopplerStructureListNumbering>(poppler_structure_element);
}

/* PrintField Attributes */

/**
 * poppler_structure_element_get_form_role:
 * @poppler_structure_element: A #PopplerStructureElement
 *
 * Obtains the role of a form structure element that is part of a form, or is
 * a form field. This hints how the control for the element is intended
 * to be rendered.
 *
 * Return value: A #PopplerStructureFormRole value.
 *
 * Since: 0.26
 */
PopplerStructureFormRole poppler_structure_element_get_form_role(PopplerStructureElement *poppler_structure_element)
{
    g_return_val_if_fail(poppler_structure_element_get_kind(poppler_structure_element) == POPPLER_STRUCTURE_ELEMENT_FORM, EnumNameValue<PopplerStructureFormRole>::values[0].value);

    /*
     * The Role attribute can actually be undefined.
     */
    const Object *value = attr_value_or_default(poppler_structure_element, Attribute::Role);
    if (value == nullptr) {
        return POPPLER_STRUCTURE_FORM_ROLE_UNDEFINED;
    }

    return name_to_enum<PopplerStructureFormRole>(value);
}

/**
 * poppler_structure_element_get_form_state:
 * @poppler_structure_element: A #PopplerStructureElement
 *
 * For a structure element that is a form field, obtains in which state
 * the associated control is expected to be rendered.
 *
 * Return value: A #PopplerStructureFormState value.
 *
 * Since: 0.26
 */
PopplerStructureFormState poppler_structure_element_get_form_state(PopplerStructureElement *poppler_structure_element)
{
    g_return_val_if_fail(poppler_structure_element_get_kind(poppler_structure_element) == POPPLER_STRUCTURE_ELEMENT_FORM, EnumNameValue<PopplerStructureFormState>::values[0].value);
    return attr_to_enum<PopplerStructureFormState>(poppler_structure_element);
}

/**
 * poppler_structure_element_get_form_description:
 * @poppler_structure_element: A #PopplerStructureElement
 *
 * Obtains the textual description of the form element. Note that the
 * description is for informative purposes, and it is not intended
 * to be rendered. For example, assistive technologies may use the
 * description field to provide an alternate way of presenting an
 * element to the user.
 *
 * The returned string is allocated by the function. When it is
 * not needed anymore, be sure to call g_free() on it.
 *
 * Return value: (transfer full): A string, or %NULL if the attribute
 *    is not defined.
 *
 * Since: 0.26
 */
gchar *poppler_structure_element_get_form_description(PopplerStructureElement *poppler_structure_element)
{
    g_return_val_if_fail(poppler_structure_element_get_kind(poppler_structure_element) == POPPLER_STRUCTURE_ELEMENT_FORM, NULL);

    const Object *value = attr_value_or_default(poppler_structure_element, Attribute::Desc);
    if (value == nullptr) {
        return nullptr;
    }
    if (value->isString()) {
        return _poppler_goo_string_to_utf8(value->getString());
    }
    if (value->isName()) {
        return g_strdup(value->getName());
    }

    g_assert_not_reached();
    return nullptr;
}

/* Table Attributes */

/**
 * poppler_structure_element_get_table_row_span:
 * @poppler_structure_element: A #PopplerStructureElement
 *
 * Obtains the number of rows the table element spans to.
 *
 * Return value: A positive, non-zero value.
 *
 * Since: 0.26
 */
guint poppler_structure_element_get_table_row_span(PopplerStructureElement *poppler_structure_element)
{
    g_return_val_if_fail(poppler_structure_element_get_kind(poppler_structure_element) == POPPLER_STRUCTURE_ELEMENT_TABLE, 0);
    return static_cast<guint>(attr_value_or_default(poppler_structure_element, Attribute::RowSpan)->getInt());
}

/**
 * poppler_structure_element_get_table_column_span:
 * @poppler_structure_element: A #PopplerStructureElement
 *
 * Obtains the number of columns the table element spans to.
 *
 * Return value: A positive, non-zero value.
 *
 * Since: 0.26
 */
guint poppler_structure_element_get_table_column_span(PopplerStructureElement *poppler_structure_element)
{
    g_return_val_if_fail(poppler_structure_element_get_kind(poppler_structure_element) == POPPLER_STRUCTURE_ELEMENT_TABLE, 0);
    return static_cast<guint>(attr_value_or_default(poppler_structure_element, Attribute::ColSpan)->getInt());
}

/**
 * poppler_structure_element_get_table_headers:
 * @poppler_structure_element: A #PopplerStructureElement
 *
 * Obtains an array with the names of the table column headers. This is only
 * useful for table header row elements.
 *
 * The array with the results is allocated by the function. The number
 * of items in the returned array can be obtained with g_strv_length().
 * The returned value must be freed using g_strfreev().
 *
 * Return value: (transfer full) (array zero-terminated=1) (element-type gchar*):
 *    Zero-terminated array of strings with the table header names,
 *    or %NULL if the attribute is not defined.
 *
 * Since: 0.26
 */
gchar **poppler_structure_element_get_table_headers(PopplerStructureElement *poppler_structure_element)
{
    g_return_val_if_fail(poppler_structure_element_get_kind(poppler_structure_element) == POPPLER_STRUCTURE_ELEMENT_TABLE, NULL);

    const Object *value = attr_value_or_default(poppler_structure_element, Attribute::Headers);
    if (value == nullptr) {
        return nullptr;
    }

    g_assert(value->isArray());

    const guint n_values = value->arrayGetLength();
    gchar **result = g_new0(gchar *, n_values + 1);

    for (guint i = 0; i < n_values; i++) {
        Object item = value->arrayGet(i);

        if (item.isString()) {
            result[i] = _poppler_goo_string_to_utf8(item.getString());
        } else if (item.isName()) {
            result[i] = g_strdup(item.getName());
        } else {
            g_assert_not_reached();
        }
    }

    return result;
}

/**
 * poppler_structure_element_get_table_scope:
 * @poppler_structure_element: A #PopplerStructureElement
 *
 * Obtains the scope of a table structure element.
 *
 * Return value: A #PopplerStructureTableScope value.
 *
 * Since: 0.26
 */
PopplerStructureTableScope poppler_structure_element_get_table_scope(PopplerStructureElement *poppler_structure_element)
{
    g_return_val_if_fail(poppler_structure_element_get_kind(poppler_structure_element) == POPPLER_STRUCTURE_ELEMENT_TABLE, EnumNameValue<PopplerStructureTableScope>::values[0].value);
    return attr_to_enum<PopplerStructureTableScope>(poppler_structure_element);
}

/**
 * poppler_structure_element_get_table_summary:
 * @poppler_structure_element: A #PopplerStructureElement
 *
 * Obtains the textual summary of the contents of the table element. Note that
 * the summary is meant for informative purposes, and it is not intended
 * to be rendered. For example, assistive technologies may use the
 * description field to provide an alternate way of presenting an element
 * to the user, or a document indexer may want to scan it for additional
 * keywords.
 *
 * The returned string is allocated by the function. When it is
 * not needed anymore, be sure to call g_free() on it.
 *
 * Return value: (transfer full): A string, or %NULL if the attribute
 *    is not defined.
 *
 * Since: 0.26
 */
gchar *poppler_structure_element_get_table_summary(PopplerStructureElement *poppler_structure_element)
{
    g_return_val_if_fail(POPPLER_IS_STRUCTURE_ELEMENT(poppler_structure_element), NULL);

    const Object *value = attr_value_or_default(poppler_structure_element, Attribute::Summary);
    if (value == nullptr) {
        return nullptr;
    }
    if (value->isString()) {
        return _poppler_goo_string_to_utf8(value->getString());
    }
    if (value->isName()) {
        return g_strdup(value->getName());
    }

    g_assert_not_reached();
    return nullptr;
}