GNOME Bugzilla – Bug 681249
Advise user to install poppler-data if applicable
Last modified: 2018-05-22 14:39:26 UTC
(This bug report is a copy of downstream bug report https://bugs.launchpad.net/ubuntu/+source/evince/+bug/1030575 with minor edits.) In order to display CJK fonts in PDF files, Evince needs the package "poppler-data" to be installed. If "poppler-data" isn't installed, any CJK text in a document is invisible, and Evince doesn't indicate to the user why the text is invisible. Suggested enhancement to Evince: (modified from https://bugs.launchpad.net/ubuntu/+source/poppler/+bug/197537/comments/26 ) 'What needs to be done is for Evince to display a warning like "CJK font support is included in the package poppler-data, which is currently not installed on your system" in these cases.' An intended solution has been made (documented in https://bugs.launchpad.net/ubuntu/+source/language-selector/+bug/893920 ) by modifying Ubuntu's "language-selector", starting with Ubuntu 12.04, to install poppler-data unconditionally. Even so, there are still some reasons for the suggested enhancement to Evince: * Someone may un-install poppler-data, either accidentally or on purpose, (if Evince was un-installed as part of this, then Evince may then be re-installed without poppler-data,) then try to view a PDF file in Evince that contains CJK fonts. * I don't know much about language-selector, so I suppose there may be cases when language-selector doesn't run, either on upgrade from a version of Ubuntu prior to 12.04, or on a new install of 12.04 or higher. * If the issue is addressed upstream (in Evince), then users of other Linux distros would benefit. The issue of invisible "CJK" fonts can affect PDF documents that contain only Latin characters but were produced by software that is set up for CJK speakers. So the issue can affect non-CJK-speaking Evince users. My Evince package version is 2.32.0-0ubuntu12.4 on Ubuntu 11.04 (natty).
I don't think we should simply *tell* the user what to install. Either use packagekit to automatically (or after confirmation) install the required dependencies, or we should expect that distributions just always install poppler-data.
I prefer the packagekit option. The reason that poppler-data can't always be installed on Ubuntu (for example) is that poppler-data is too big to fit on the install CD. So the only automatic install of poppler-data done by Ubuntu is if the PC is on the Internet to download the package. There could be Ubuntu machines that aren't on the Internet, so they don't have poppler-data, but someone may still try to view a PDF file with CJK text on these machines. Also, as I recall, a notification icon prompts the user to run Ubuntu's "language-selector" after the OS is installed, but the user may ignore this notification. Until language-selector is run, poppler-data doesn't get automatically installed. A similar situation could happen on other distros. There are likely distros that are oriented toward using minimal disk space and whose maintainers would likewise want poppler-data to be installed only conditionally. Although Evince is part of Gnome, Evince is also bundled with non-Gnome distros. In all these cases, the user should at least be given some info as to why the document appears to have no text. Prompting the user to allow a download & install of poppler-data is fine as well.
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