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Okular, Debian, and copy restrictions

Jul 01, 2009, 00:16 (7 Talkback[s])
(Other stories by Jonathan Corbet)

"The PDF file format includes a number of protection flags which specify whether the reader is allowed to print the file, make changes, or to copy out excerpts. There is nothing in the format which actively prevents such activities; these flags are simply instructions which any application operating on PDF files is expected to observe. If the "no copy" flag is set, cutting and pasting text from the file should - by the standard - be disabled in any reader application. Developers of free applications have, as a general rule, never quite gotten around to implementing this kind of restriction - even though the low-level poppler PDF-processing library makes such support possible. Applications which do implement this "feature" tend to disable it by default.

"This is not the case with Okular, though. An attempt to select text from a suitably-marked PDF file yields a rather confusing dialog which reads "copy forbidden by DRM" (see the image to the right). Amusingly, the application will still allow the selected region to be saved as an image file, but sending the text to the clipboard is not allowed. There is a configuration option which disables this behavior, but the default setting is to enforce the copy restriction flag."

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