class PDF::NameTree

• PDF::NameTree
• Reference
• Object

Overview

A name tree serves a similar purpose to a dictionary—associating keys and values—but by different means. A name tree differs from a dictionary in the following important ways:

• Unlike the keys in a dictionary, which are name objects, those in a name tree are strings.

• The keys are ordered.

• The values associated with the keys may be objects of any type, but they must always be specified via indirect object references.

• The data structure can represent an arbitrarily large collection of key-value pairs, which can be looked up efficiently without requiring the entire data structure to be read from the PDF file. (In contrast, a dictionary is subject to an implementation limit on the number of entries it can contain.)

A name tree is constructed of nodes, each of which is a dictionary object. Table 3.22 shows the entries in a node dictionary. The nodes are of three kinds, depending on the specific entries they contain. The tree always has exactly one root node, which contains a single entry: either Kids or Names but not both. If the root node has a Names entry, it is the only node in the tree. If it has a Kids entry, then each of the remaining nodes is either an intermediate node, containing a Limits entry and a Kids entry, or a leaf node, containing a Limits entry and a Names entry.

Included Modules

• PDF::Renderable

Defined in:

pdf/data/nametree.cr

Constructors

• .new(type : PDF::NameTree::Type, kids : Nil | Array(PDF::NameTree), names : Nil | Array(Tuple(String, PDF::PdfObj)))

Instance Method Summary

• #limits : Array(String) | Nil

  Limits array (Intermediate and leaf nodes only; required) An array of two strings, specifying the (lexically) least and greatest keys included in the Names array of a leaf node or in the Names arrays of any leaf nodes that are descendants of an intermediate node.

• #render_to_pdf(io : IO) : IO

  for mixing-in module Renderable

Constructor Detail

Instance Method Detail