Ubuntu Manpage: nsdejavu - DjVu browser plugin

Provided by: djview-plugin_4.10.6-3_amd64

NAME

       nsdejavu - DjVu browser plugin

SYNOPSIS

       /usr/lib/x86_64-linux-gnu/mozilla/plugins/nsdejavu.so

DESCRIPTION

       The shared library nsdejavu.so uses the Netscape browser plugin API to display DjVu images in in a number
       of  popular  web browsers.  Different web browsers provide various level of support for Netscape plugins.
       Please check section "Browser Compatibility" for instructions on how to enable the DjVu browser plugin.

       The DjVuLibre browser plugin works by invoking a standalone viewer with the special command  line  option
       -netscape.   The  plugin  first  searches  a  program  named djview.  If this program cannot be found, it
       searches for djview4 and finally djview3.  It is always possible to  override  this  search  strategy  by
       setting the environment variable NPX_DJVIEW to the full path of the desired executable.

MIME TYPES AND EXTENSIONS

       Typing  the  URL  of  a recognized DjVu document in your web browser should automatically invoke the DjVu
       browser plugin.  Each browser uses different methods to determine that a particular URL is in fact a DjVu
       document.  Web server normally provide a MIME type to web browsers.  The  official  MIME  type  for  DjVu
       documents is image/vnd.djvu.  For compatibility with ancient versions of the DjVu viewer, it is common to
       use instead the experimental MIME type image/x-djvu or image/x.djvu.  Web servers should be configured to
       send  the  proper MIME type for DjVu documents.  Most web browsers also recognize files ending with .djvu
       or .djv as DjVu files.

       An easy way to check if an http server is giving an appropriate content-type is to invoke  the  following
       command with a URL corresponding to an actual DjVu file on the server.

         curl -u URL | grep Content-Type

       The result should be one of the following, preferably the first.

         Content-Type: image/vnd.djvu
         Content-Type: image/x.djvu
         Content-Type: image/x-djvu

       Any other MIME type indicates a server misconfiguration.

CGI-STYLE FLAGS

The behavior of the DjVu browser plugin can be specified by augmenting the URL using a syntax similar to
that used by the CGI programs. This syntax is described by the following template:

http://.../file.djvu?djvuopts&keyword=value&keyword=value&...

The DjVu browser plugin only recognizes keywords that appear after the word djvuopts. The keywords
recognized by each viewer are listed in the corresponding man page. Unrecognized keywords are ignored.
The most common keywords are:

page=pagename
Specify which page is displayed by name or by ordinal number.

zoom=zoomfactor
Set the zoom factor. Legal values for zoomfactor are:
┌────────────────────────────────────────────────────────┐
│ number Magnification factor in range 10% to 999%. │
│ one2one Select the "one-to-one" mode. │
│ width Select the "fit width" mode. │
│ page Select the "fit page" mode. │
│ stretch Stretch the image to the plugin window size. │
└────────────────────────────────────────────────────────┘

BROWSER COMPATIBILITY

       The DjVu browser plugin has been tested with several popular web browsers: Netscape 4 and 6; Gecko  based
       browsers  such as Mozilla, Galeon and Firefox; KHTML based browsers such as Konqueror; and Opera.  Please
       read the browser documentation to find out where the plugin library should be installed.

EMBEDDING DJVU IMAGES IN HTML PAGES

       You can integrate DjVu content on an HTML web page with either the <embed> or  the  <object>  tag.   This
       method will work even if your web server does not support the DjVu MIME type.  The CGI style flags can be
       directly  used  as  attributes of the embedding tag.  The following example shows the W3C standard syntax
       with the OBJECT tag:

          <object data="myfile.djvu" type="image/vnd.djvu"
                    width="100%" height="100%" >
              <param name="page" value="iii">
              <param name="zoom" value="stretch">
              This browser cannot render djvu data.
          </object>

       And this is the customary syntax with the EMBED tag:

          <embed src="myfile.djvu" type="image/vnd.djvu"
                    width="100%" height="100%"
                    page="iii" zoom="stretch"></embed>

INTERFACING THE DJVIEW PLUGIN WITH JAVASCRIPT

Recent versions of the djview4 plugin can be controlled from the JavaScript interpreter of browsers
implementing the Mozilla NPRuntime API. To access the plugin object, include the attribute
id="pluginname" into the <object> or <embed> tag and use the JavaScript function
getElementById("pluginname").

The plugin object implements two methods to retrieve and set the value of the options usually recognized
as CGI-style flags. It also can evaluate a specified JavaScript expression whenever something changes in
the status of the djview interface.

pluginobject.setdjvuopt("key",value)
Set the value of the djvu option key to the character string value. This achieves the same effect
as specifying option key=value among the CGI-style flags. For instance, values of the key page
can be page IDs, page titles, page numbers, or page names.

pluginobject.getdjvuopt("key")
Return the value of the djvu option key as a string. The returned value is always a character
string, even when the return is logically a number. Boolean values are returned as strings yes or
no. Besides the usual CGI-style flags, this function recognizes the additional key pages and
returns the total number of pages in the DjVu document. An empty string is returned when the key
is not recognized.

pluginobject.onchange="code";
Ensure that string code is evaluated in the context of the plugin object whenever something
changes in the djview graphical user interface. For instance, this evaluation happens when
progressive refinements are painted, and when the user manipulates the image interactively.

pluginobject.version
Return a string describing the plugin version. This property can be used to test whether the
djview plugin is scriptable in this browser.

Note that the scriptability feature may not be accessible until the djview plugin is fully loaded.
Therefore it is advisable to check pluginobject.version from the JavaScript onload before calling any
other method.

CREDITS

       This  program  was  written  by  Andrei  Erofeev <andrew_erofeev@yahoo.com> and was then improved by Bill
       Riemers <docbill@sourceforge.net> and Léon Bottou <leonb@users.sourceforge.net>.