APPENDIX F
F
Linearized PDF
A Linearized PDF file is a file that has been organized in a special way to enable
efficient incremental access in a network environment. The file is valid PDF in all
respects, and is compatible with all existing viewers and other PDF applications.
Enhanced viewer applications can recognize that a PDF file has been linearized
and can take advantage of that organization (as well as added hint information) to
enhance viewing performance.
The Linearized PDF file organization is an optional feature available beginning in
PDF 1.2. Its primary goal is to achieve the following behavior:
•
When a document is opened, display the first page as quickly as possible. The
first page to be viewed can be an arbitrary page of the document, not neces-
sarily page 0 (though opening at page 0 is most common).
•
When the user requests another page of an open document (for example, by
going to the next page or by following a link to an arbitrary page), display that
page as quickly as possible.
•
When data for a page is delivered over a slow channel, display the page incre-
mentally as it arrives. To the extent possible, display the most useful data first.
•
Permit user interaction, such as following a link, to be performed even before
the entire page has been received and displayed.
This behavior should be achieved for documents of arbitrary size. The total num-
ber of pages in the document should have little or no effect on the user-perceived
performance of viewing any particular page.
The primary focus of Linearized PDF is optimized viewing of read-only PDF
documents. It is intended that the Linearized PDF be generated once and read
many times. Incremental update is still permitted, but the resulting PDF is no
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