nsdejavu - DjVu browser plugin

/usr/lib/netscape/plugins/nsdejavu.so

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. Both the standalone viewer djview and the DjVu browser plugin nsdejavu.so offer similar features. The DjVu browser plugin in fact is wrapper that invokes the standalone viewer program in remote control mode. This man pages describes those features that are specific to the browser plugin. Additional information can be found in the djview(1) man page.

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. See the DjVu tutorial for more information ( http://www.djvuzone.org/support/tutorial/ ). 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 a DjVu file on the server, such as http://nips.djvuzone.org/djvu/nips13/AgueraFairhallBialek.djvu.

wget --debug --output-document=/dev/null URL 2>&1 | 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.

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

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

The DjVu browser plugin only recognizes keywords that appear after the word djvuopts. Unrecognized keywords are silently ignored. The following keywords are recognized:

passive

Cause the image to be displayed in a manner similar to an ordinary web image. The default zoom factor is changed to "Fit Page". The toolbar, the pop-up menu, the scroll bar, and the keyboard shortcuts are disabled. The default is no.

scrollbars=(yes|no)

Enable or disable the presence of scroll bars when the full image size exceeds the plugin window size. The default is yes.

menu=(yes|no)

Enable or disable the pop-up menu. The pop-up menu is enabled by default.

keyboard=(yes|no)

Enable or disable the DjVu plugin keyboard shortcuts. The default is yes (enabled).

frame=(yes|no)

Enable or disable the display of a thin gray frame around the DjVu image. Keyboard shortcuts are enabled by default.

links=(yes|no)

Enable or disable hyper-links in the DjVu image. Hyper-links are enabled by default.

logo=(yes|no)

Enable or disable the display of the DjVu log while the plug-in is downloading data. This is enabled by default.

page=pagenum

Specify the initial page to be displayed. Page numbers are numbered from 1.

zoom=zoomfactor

Specify the initial zoom factor. Unless the toolbar, pop-up menu and keyboard are disabled, the user will be able to change the zoom factor. Legal values for zoomfactor are shown in the below:

center,box; lfI l lfB l lfB l lfB l lfB l 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.

mode=modespec

Specify the initial display mode. Unless the toolbar and pop-up menu are disabled, the user will be able to change it. Legal values for modespec are shown in the below:

center,box; lfB l lfB l lfB l lfB l color Display the color image. bw Display the foreground mask only. fore Display the foreground only. back Display the background only.

hor_align=keyword

Specify the horizontal position of the page in the viewer window. (This does not specify what part of the page will be shown, but rather how margins will be laid out around the page in the plugin window.) Argument keyword must be left, center, or right.

ver_align=keyword

Specify the vertical position of the page in the viewer window. (This does not specify what part of the page will be shown, but rather how margins will be laid out around the page in the plugin window.) Argument keyword must be top, center, or bottom.

toolbar=keyword{(,|+|-)keyword}

Controls the appearance and the contents of the toolbar. The argument of option toolbar is composed of a number of keywords separated by characters comma, plus or minus. The appearance of the toolbar is controlled by keywords placed before the first occurrence of a character plus or minus. The following keywords are recognized in this context:

center,box; lfB l lfB l lfB l lfB l lfB l no Disable toolbar. always Disable toolbar "autohide" mode. auto Enable toolbar "autohide" mode. top Place toolbar along top edge (not implemented). bottom Place toolbar along bottom edge.

The contents of the toolbar is controlled by keywords placed after the first occurrence of a character plus or minus. Each keyword adds (after a plus) or remove (after a minus) a particular toolbar button or group of buttons. The initial content of the toolbar is determined by the first occurrence of a character plus or minus. When this is a plus the toolbar is initially empty. When this is a minus the toolbar is initially full. The following keywords are recognized:

center,box; lfB l lfB l lfB l lfB l lfB l lfB l lfB l lfB l lfB l lfB l lfB l lfB l lfB l fore,back,color,bw for the display mode selection tool. rescombo for the zoom selection tool. zoom for the zoom buttons. pan for the panning mode button. zoomsel for the zooming mode button. textsel for the text selection mode button. rotate for the image rotation buttons. search for the text search button. save for the save button. print for the print button. pagecombo for the page selection tool. firstlast for the first-page and last-page buttons. prevnext for the previous- and next-page buttons. backforw for the back and forward buttons.

highlight=x,y,w,h[,color]

Display a highlighted rectangle at the specified coordinates and with the specified color. Coordinates x, y, w, and h are measured in document image coordinates (not screen coordinates). The origin is set at the bottom left corner of the image. The color color must be given in hexadecimal RRGGBB format. Omitting the color argument means to use XOR highlighting. Multiple highlighted zone can be specified.

rotate=(0|90|180|270)

Rotate the djvu image by the specified angle expressed in degrees counter-clockwise.

print=(yes|no)

Enable or disable printing the djvu image. Printing is enabled by default.

cache=(yes|no)

Enable or disable the caching of fully decoded pages of the document. Caching is on by default. Caching of documents whose URL does not contain extension is off by default.

A good way to integrate DjVu content on your web page is to use the EMBED directive of the HTML language. An advantage of this method is that it will work even if your web server does not support the DjVu MIME type. Furthermore, the CGI style flags can be directly used as attributes of the EMBED tag. Here is an example:

<embed src= " myfile.djvu" " type=" " image/x-djvu" " "

000000000 width= " 100%" " height=" " 100%" " "

"000000000 passive=yes zoom=stretch > </embed>

The DjVu browser plugin has been tested with several popular web browsers:

Netscape 4

Netscape 6

Mozilla

Galeon

Mozilla Firebird

Konqueror

Opera

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

djvu(1), ddjvu(1), djview(1)