Changing Configuration Parameters

The IIP service runs as an NSAPI process. The process must remain enabled for the ImageIgniter server to function.

The IIP service relies on subcomponents called Image Source Modules (ISMs) to handle JPEG and FlashPix image types. You can enable each ISM individually.

You can also choose between two methods for mapping OpenPix images. You can either use NSAPI URL mapping or specify a root directory for each image type. Enabling mapping (the default) allows the IIP service to use all the virtual paths configured in NES. Since many web sites rely heavily on virtual paths, HP recommends enabling NSAPI URL mapping unless image locations are carefully managed.

If virtual mapping is enabled, authors must provide absolute paths for images or specify the locations relative to the HTML page. If you disable virtual mapping, authors must specify paths relative to the root directories specified in the "FPX root directories" and "JPEG root directories" fields. Disabling virtual mapping makes specifying paths more complex for users of authoring tools, which generally expect virtual directories to be used.

	NOTE: If you enable virtual mapping, consider using NES to disable browsing to the image directories. Otherwise, users will be able to easily find the images and download them directly. Another way to disable image downloading is to disable virtual mapping in OpenPix and set FPX and JPEG root directories outside the web content hierarchy. Virtual paths in NES are not affected.

You can choose the interval at which image content expires after being served. This setting determines the maximum length that images can be stored on proxy caches. (The proxy server can specify an interval shorter than this setting for flushing its cache.) Choose a short interval if your images are updated frequently and a longer interval if the image content is stable.

The IIP server has a session tracking feature used to track the use of images. You can set options about session tracking, including the persistence time for sessions. (Session tracking works only if the Session ID option is selected in the Logging area.) Session tracking information is available in web server logs, but is not currently used by OpenPix log analysis features.

You can choose whether to enable logging for the IIP service. If logging is enabled, you can choose from two categories of information to log. You must open the log in a word processor or use a third-party tool to view this information.

These are the logging categories:

You use the Internet Imaging Protocol Service Configuration Parameters page to configure the IIP service. Depending on your screen size, you may need to scroll to see the entire page.

You can change several configuration settings that affect performance: the number of images and tiles cached, the maximum image size, and the JPEG quality factor.

To optimize performance, the FID service caches frequently accessed portions of images. To reduce the impact on system memory, you can limit the size of this cache by the number of source images or by the number of tiles per image cached. Each cached tile uses about 1 KB of system memory, so storing 100 tiles from 100 images uses about 10 MB.

To reduce the computational load on the server, you can set maximum image width and height parameters to limit the size of the image that is assembled by the FID service. These settings do not affect the maximum size of the underlying source image.

The quality setting for JPEG images impacts download time and image quality. A small number such as 20 creates small image files, but the images are grainy when displayed. A high number, such as 100, creates relatively large image files that display cleanly. The default value of 95 is generally an acceptable compromise.

Several FID configuration settings affect the presentation of images.

The default resolution level setting influences the appearance of images when the authored content doesn't have a resolution level parameter defined. In the absence of this parameter, the FID service scales the image from the default resolution level entered here into the desired image size.

The resolution level refers to the tiled FlashPix image format. Level 0 corresponds to an image that fits into a single 64x64-pixel tile. Level 1 corresponds to an image that fits into a 128x128-pixel area (a maximum of four 64x64 tiles.) Level 2 refers to a 256x256-pixel area, and so on.

The IIP Service hostname and port used by the FID service are normally the same as those of the web server, but can be set to a separate OpenPix server for load-sharing.

You use the Flat Image Delivery Configuration Parameters page to configure the FID service. Depending on your screen size, you may need to scroll to see the entire page.

The location of the toolbar for OpenPix images is normally determined by the Style attribute in an OpenPix image tag. Similarly, the Type attribute determines the type of viewer that will be used. You can override these settings in an authored page with the "Override toolbar location?" and "Override viewer type?" fields. For example, you can modify the entire site to deliver FID-generated images instead of FlashPix images viewed in a Java or ActiveX viewer. Similarly, the toolbar style override forces all images on a web site to be presented using the same toolbar style.

The "Enable image downloads" button allows you to choose whether users should be able to download images that are delivered via the ImageIgniter server.

Adaptive Delivery works by parsing outgoing HTML files and replacing OpenPix image tags with HTML code that specifies the viewer type and image source. You can configure the service for the types of files that it parses and for the desired viewer type and appearance.

Adaptive Delivery normally scans every outgoing file with mime type text/html. In the "File extensions" field, you can enter file types to correspond to the web content you use with OpenPix. For example, your system might use Perl and return HTML content in files with the .PL file name extension. Adaptive Delivery can be configured to parse only those files before returning the results.

By using file extensions instead of relying on mime type, you can exclude and include files more precisely. This feature can improve server performance because parsing the outgoing files is CPU-intensive. If you include more than one file type, separate the file type extensions with spaces (for example: htm pl asp).

Separate sections display information about the ActiveX and Java viewer components used with OpenPix. This information is normally for reference only, but you can change it under certain circumstances—for example, to specify a customized view or to facilitate rollback to an earlier version.

	CAUTION: Changing the fields to improper values will disable use of the viewers. Make changes to these fields only when you're absolutely sure of the information you enter.

You use the Adaptive Delivery Configuration Parameters page to configure the Adaptive Delivery service. Depending on your screen size, you may need to scroll to see the entire page.