NSDEJAVU(1)							     DjView-4							       NSDEJAVU(1)

NAME

       nsdejavu - DjVu browser plugin

SYNOPSIS

       /usr/lib/x86_64-linux-gnu/netscape/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.  Differ-
       ent 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 man pages for djview3(1) and djview4(1).  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 intepreter 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 getEle-
       mentById("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 logi-
	      cally  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
       Leon Bottou <leonb@users.sourceforge.net>.

SEE ALSO

       djvu(1), ddjvu(1), djview4(1) djview3(1)

DjView-4							     1/4/2007							       NSDEJAVU(1)