Image List Files let you create “documents” that act like multi-page files for viewing. They are a collection of single- or multi-page image files. List Files provide several advantages over conventional multi-page image files:

• List Files are very small since they contain only ASCII text. A multi-page image file is much larger and requires more transit time.
   
• The List File’s images are requested and transferred one at a time after the List File is loaded. A multi-page image is contained in one large file and must be completely transferred at one time.
   
• List Files provide for quick and easy composition of multi-page documents on the fly.
   
• List Files are printed differently than conventional image files. A separate print routine is called that allows you to “print on demand” the page or pages needed from the list file. You can return to your work while the pages are printing.
   
• You can control the headers and footers printed on all the pages or on individual pages using directives inside the List File.
   

Once you create a list file, you can:

• View and/or print as if it was a multi-page TIFF file.
• Print list files without viewing them. Please see Printing without Viewing for more information.
• Batch download sets of files to your local drive or network. Please see Batch Downloading for more information.

This section contains information on these topics.

• Creating Image List Files
• Using Image List Files
• Printing Image List Files
• Batch Downloading

Creating Image List Files

An Image List File is actually an ASCII text file containing information about the List File’s type, the name of the “document,” directives (special instructions) about headers, footers, and the files to be included in the document. You can create a list file that can be used for viewing images, printing images, and/or downloading images. If you look at an Image List File in a text editor (such as NotePad), it will look similar to this:

rSample Image List File
c:\pic\prizmdoc\image\candy.tif
c:\pic\prizmdoc\image\3page.tif
file:///c|/pic/prizmdoc/image/prizmmed.tif
http://www.pegasusimaging.com/pic_main.tif
docs/framework/image/drawing10.tif
/framework/getImageList?action=getlist&count=5

You can create an Image List File using any tool that you prefer. You can create them with an editor like Notepad, or Microsoft Word, or any other application that can create plain text files. List Files can also be generated with CGI scripts, servlets, Active Server Pages, or similar automated applications.

A List File contains a header line followed by any number of directives and image references. The following elements can be included in an Image List File. Only one element per line is allowed.

Header Line. The header line must be the first line of the List File. The header line contains the letter "r" followed by the document name. The letter "r" indicates the type of image list file. Currently, "r" and "+" are the only values recognized by the Prizm Viewer. The "r" indicates that the images in the List File may have relative path names. The document name is a text string that describes the List File. For example, the following is a valid header line:

rNew List File Document

Directives. Directives are special instructions regarding headers, footers, and other features. Directives always begin with a pound sign (#). Directives are active for any image references that sequentially follow them in the List File until a new directive replaces the current directive. For values and descriptions, you will need to review the information in two tables: the Directives table and the Parameter-Directive table. Both tables are in the Object/Embed Tag and Directives section, use either of the links above to access these tables.

Image References
Image references describe where to find the image that is to be displayed or printed. Image references can be either absolute URLs or they can be relative URLs. Absolute URLs contain all the information that you need to put in a link to the image (i.e., http://www.myserver.com/mydirectory/myfile.tif). Relative URLs are relative to the location of the Image List File. You can also insert the name of a CGI script, servlet or other application that will generate a valid URL to an image file. The following types of relative image references are supported:

• Directory/Filename.ext. When specified in this manner, the path to the image file is assumed to be relative to the location of the List File. The following examples are valid calls:
  • drawing.Dispatcher?action=ImageList&count=3&mode=list mySubDirectory/myfile.tif
• /Directory/Filename.ext. When specified in this manner, the path to the image file is assumed to be relative to the URL of the List File. The following is a valid example:
  • /servlet/getList="172zeuw78" mySubDirectory/myfile.tif

When creating list files, remember these important points:

• Text files can be used within a List File to convey messages to the user. Text files should be 32K or less in size. If you include a text file that is larger than 32K, the Prizm Viewer will display the first 32K (approximately 32,000 characters) of the text file. Text files specified inside a List File MUST have an extension of .txt.
• If you specify an image in the list file that is incorrect or missing, the Prizm Viewer displays a text message indicating the problem it encountered. If printing a list file, a page will be printed containing a similar text message.
• When creating Image List Files for images on your Internet or intranet server, the path and file names of the images in the list file need to be in valid format for Web browsers. The List File is downloaded to the user’s system and is interpreted by the Viewer. The Viewer will look for the files on the user’s local system if the images specified in the List File begin with “file:///”or a drive letter.
• For users to access Image List Files stored on your Internet or intranet server, you must add List Files to the list of MIME types recognized by your Web Server. Image List Files have a MIME type of “image/x-list” with an extension of “*.list” and "image/x-lst with an extension of "*.lst." Batch download List files have a MIME type of "image/x-list-export" with an extension of "*.xlo." Print List files have a MIME type of "image/x-pzm" with an entension of "*.pzm."

If you were to create a combination List File that could be used for viewing, printing, or downloading, it would look similar to the sample below:

Combination List (Used for Viewing, Printing, or Downloading):

rSample Image List File for Viewing, Printing or Downloading
fontsize=”12”
printheader1=”This is the first header on the page”
printfooter1=”This is the only footer on the page”
EXPORTNAME=”drawing15-2-a.tif”
http://www.myserver.com/large-drawing.tif
printheader1=”I replace the print header 1 above”
printfooter2=”I am an additional footer on all subsequent pages”
EXPORTNAME=”drawing15-2-.tif”
http://www.myserver.com/script?f=parameter1&d=parameter2
EndURL=”http://www.myserver.com"

Using Image List Files

When you open an Image List File in your browser, the document name you have given the List File appears in the status bar, and the first image is retrieved and displayed. To move from page to page, use the pop-up menu or the toolbar’s paging buttons.

Below is an Image List File displayed by the Prizm® Viewer.

Click here to see the list file in a full window...

To use the pop-up menu, right-click the image, then select the “Paging” menu item. Next, select the submenu item that you want: “Previous” page, “First” page, “Last” page, “Next” page, or specify a page using “Go to Page...” The toolbar’s paging buttons look like this:

Shows the Previous page
Shows the Next page
Allows you to select a page by its number

As you page through a multi-page image, the Prizm Viewer remembers how the image was displayed before you changed pages. When you return to a page, it will appear just as you left it.

What happens if one of the images in your Image List File is a multi-page image file (i.e., a multi-page TIF image)? Separate image files in an Image List File are called “pages.” Images in a multi-page image file are called “sheets.” Thus, every page in an Image List File can contain one or more sheets. The concept is similar to a compact disc player that accepts multiple discs. Each disc can contain one or more audio tracks. The collection can be browsed by disc (page), and each disc can be further browsed by track (sheet).

To browse the pages of an Image List File, use the same toolbar buttons and pop-up menu items used to browse a multi-page image file. When you view a page that contains a multi-page image you will notice that a second set of paging buttons and menu items become active. To browse the sheets in this page, right-click the image, select the “Paging” menu, and then select submenu items that you want: “First Sheet,” “Next Sheet,” “Previous Sheet,” “Last Sheet” or “Go To Sheet...” You can also use the toolbar buttons to browse the sheets of a multi-page image:

Shows the Previous Sheet
Shows the Next Sheet
Allows you to Go to Sheet by specifying its sheet number

As mentioned, Prizm Viewer remembers how you left a page so when you return to it, it looks just like it did when you left. When you have a multi-page image file inside a List File, the Prizm Viewer "memory" applies only to the first sheet of the multi-page image file. The remaining sheets are displayed using your initial display defaults as defined in Prizm Viewer Preferences. For more information on Prizm Viewer Preferences, see Setting Preferences.

Printing Image List Files

When you are viewing an Image List File in the Prizm Viewer and click the print button or select "Print" from the pop-up menu, the Prizm Viewer handles the List File internally. A standard print dialog displays and then sends the images to be printed when you click OK. The Prizm Viewer can print your list file in the "background" and not tie up your browser during the downloading and spooling of the files to be printed. 

You can also print images without viewing them. For more information, see the Printing without Viewing section.

Batch Downloading

Batch Downloading allows easy downloading of a set of files to a hard drive or network drive. These files are then available locally to be viewed or modified using a suitable software application. This process is very much like Printing Without Viewing.

For more information batch downloading file, please see the section called Batch Downloading.