Struct StructTree

Source

pub struct StructTree {
    pub elements: Vec<StructElement>,
    pub top: Vec<Option<usize>>,
}

Expand description

One page’s view of the document’s structure tree.

use pdfrum_common::{Diagnostics, Limits};
use pdfrum_doc::StructTree;
use pdfrum_object::{Dict, Name, NoResolve, Object};

// "Tagged" is `/MarkInfo /Marked` read as a non-zero integer, so a
// Boolean `true` and a written `1` both count.
let catalog = Dict::from_pairs([(
    Name::from("MarkInfo"),
    Object::Dict(Dict::from_pairs([(Name::from("Marked"), Object::Bool(true))])),
)]);

let (limits, mut diags) = (Limits::default(), Diagnostics::default());
let tree = StructTree::load_page(
    &catalog, &Dict::default(), 1, &NoResolve, &limits, &mut diags,
).expect("the document is tagged");

// No `/StructTreeRoot`: a tree, but an empty one.
assert!(tree.elements.is_empty());

Fields§

§elements: Vec<StructElement>

Every element reached from this page, in discovery order. Kid and parent links are indices into this table.

§top: Vec<Option<usize>>

The root’s /K slots. Sized from /K, filled only where the upward walk reached a top-level element, so a None is normal.

Implementations§

Source §

impl StructTree

Source

pub fn load_page<R: Resolve>( catalog: &Dict, page: &Dict, page_obj_num: u32, r: &R, limits: &Limits, diags: &mut Diagnostics, ) -> Option<StructTree>

Builds the tree for one page, or nothing when the document is not tagged.

“Tagged” is catalog[/MarkInfo][/Marked] read as a non-zero integer, and a Boolean has an integer reading of zero or one — so the spec-conforming /Marked true works, and so does a file writing /Marked 1.

use pdfrum_common::{Diagnostics, Limits};
use pdfrum_doc::StructTree;
use pdfrum_object::{Dict, Name, NoResolve, Object};

// "Tagged" is `/MarkInfo /Marked` read as a non-zero integer, so a
// Boolean `true` and a written `1` both count.
let catalog = Dict::from_pairs([(
    Name::from("MarkInfo"),
    Object::Dict(Dict::from_pairs([(Name::from("Marked"), Object::Bool(true))])),
)]);

let (limits, mut diags) = (Limits::default(), Diagnostics::default());
let page = Dict::default();
assert!(
    StructTree::load_page(&catalog, &page, 1, &NoResolve, &limits, &mut diags).is_some(),
);

// An untagged document has no tree at all -- a different answer from
// an empty one.
assert!(
    StructTree::load_page(
        &Dict::default(), &page, 1, &NoResolve, &limits, &mut diags,
    ).is_none(),
);