信息技术数字出版EPUB3第6部分:EPUB规范片段标识符

[中文适用范围]： 本规范定义了通过使用片段标识符在EPUB®出版物中引用任意内容的标准方法。网络已经证明超链接的概念非常强大，但由于缺乏标准化方案来链接到其中，EPUB出版物未能充分利用这一优势。尽管为个别阅读系统开发和实施了专有方案，但没有通用语法就无法实现跨平台互操作性。通过定义可以唯一标识发布物中任何位置或简单范围的任意结构参考，即EPUB CFI（Canonical Fragment Identifier），本规范旨在解决这一问题。 设计和范围的决定主要考虑以下因素：所使用的引用内容机制应该是互操作的：由一个阅读系统创建的阅读位置应能被另一个阅读系统使用。与现有超链接使整个网络能够相互参照一样，对EPUB内容的文档引用应该以相同的方式实现。无需修改文档即可标识EPUB文件中的每个位置。所有引用同一逻辑位置的片段标识符在比较时应相等。 比较操作（包括排序和比较测试）应在不访问所引用文件的情况下进行。简单的操纵应该是可能的，而无需访问原始文件（例如，给定一个参考深入文件中某处的位置，应该可以生成对该文件开头位置的参考）。解析器差异和文档修订应能恢复目标位置。 应支持对简单连续范围的表达。此外，应提供一种可扩展机制来容纳未来的位置恢复启发式方法。 [外文原描述]： This specification, EPUB Canonical Fragment Identifier (epubcfi), defines a standardized method for referencing arbitrary content within an EPUB® Publication through the use of fragment identifiers. The Web has proven that the concept of hyperlinking is tremendously powerful, but EPUB Publications have been denied much of the benefit that hyperlinking makes possible because of the lack of a standardized scheme to link into them. Although proprietary schemes have been developed and implemented for individual Reading Systems, without a commonly-understood syntax there has been no way to achieve cross-platform interoperability. The functionality that can see significant benefit from breaking down this barrier, however, is varied: from reading location maintenance to annotation attachment to navigation, the ability to point into any Publication opens a whole new dimension not previously available to developers and Authors. This specification attempts to rectify this situation by defining an arbitrary structural reference that can uniquely identify any location, or simple range of locations, in a Publication: the EPUB CFI. The following considerations have strongly influenced the design and scope of this scheme: · The mechanism used to reference content should be interoperable: references to a reading position created by one Reading System should be usable by another. · Document references to EPUB content should be enabled in the same way that existing hyperlinks enable references throughout the Web. · Each location in an EPUB file should be able to be identified without the need to modify the document. · All fragment identifiers that reference the same logical location should be equal when compared. · Comparison operations, including tests for sorting and comparison, should be able to be performed without accessing the referenced files. · Simple manipulations should be possible without access to the original files (e.g., given a reference deep in a file, it should be possible to generate a reference to the start of the file). · Identifier resolution should be reasonably efficient (e.g., processing of the first chapter is not required to resolve a fragment identifier that points to the last chapter). · References should be able to recover their target locations through parser variations and document revisions. · Expression of simple, contiguous ranges should be supported. · An extensible mechanism to accommodate future reference recovery heuristics should be provided.