VISITview Access to Remote Image Files
This capability will allow you to define a "page" of your lesson
of being a pre-loaded or defined filename, it is a URL which points to an image
somewhere "out there". This image is then loaded when you select the page
during the normal course of events.
Note: This capability will only work in non-browser (that is,
pre-loaded) mode because of Java security.
Here are the details:
Pages defined with URL-based image filenames (defined as any "filename"
that starts with "http://") will be loaded over the web during the
lesson/collaboration, and whenever the lesson is loaded in the Lesson
A page defined with a URL-based image can be used:
- for all pre-loaded lessons (be careful when using these for
recorded lessons, however, as the load time may throw off the
timing) -- the page will be loaded over the web during the
lesson, so be careful about long loops!
- for browser-based lessons ONLY if the images are loaded from the same
host machine as the HTML (and the VISITview server).
If a page is defined using a URL-based image, no other images
should be put onto that page; there is no protection against this in
the Lesson Builder yet, however.
If you want more than one frame for the page, you must either use the
wildcard (*) form of the URL. e.g.,
defines a series of filenames like "ev_mar29_0", "ev_mar29_1", etc.,
(note - the first number must always be zero)...
or...you can use embedded string substitution to imply more than one image.
which specifies 5 frames (ev_map29_00.jpg, ev_mar29_01.jpg, ev_mar29_32.jpg,
etc.). This form is also useful if your image names are in a sequence that
does not begin with zero.
The URL format has some restrictions:
- All URLs must start with "http://" (case sensitive!)
- No spaces!
- No "substitution characters" (for example, %20 for "space")
- Only image files should be pointed at (no cgi-bin generated
You may move a URL-based page around, as usual. You cannot remove
frames, etc., from the page. In otherwords, once you import a
URL-based page, you're stuck with its characteristics. You can, of
course, delete it and re-import something different if you like.
In the Lesson Builder, a new Menu Item, "Image from URL" will
be added. When you click on this, a modal dialog will appear. There
will be two text fields for you to type into:
You should type in the appropriate info, and then click "Close" button
(there is also a "Cancel" button).
- the URL:
- the URL itself for a single image.
- the URL for more than one image, using the wildcard (*) to
substitute for the sequence of numbers starting at 0 (e.g.,
- the URL with embedded string substitutions to imply multiple
frames. Enclose the substitution strings in square brackets, and
separate the strings with semi-colons. For example,
implies a 5 frame animation (img0.jpg, img1.jpg, etc).
- The number of frames (will always default to 1) which can only
be > 1 if the wildcard (*) is used. For the "embedded string
substitutions", above, this should remain = 1.
After that, the first image will be browsed into the usual thumbnail
view, and the "Append" and "Insert" buttons will be enabled. Note
that when you click either of these, the total number of frames you
specified will be inserted into the lesson on a _single page_ (see
Item #2 above).
If the thumbnail does not appear, there is an access problem (like an
invalid URL or filename). Bring the dialog up again and correct the
The thumbnails will exist only during the Lesson Builder session; when
you Save the lesson, only the URLs are written into the lesson file --
no images will be saved for those pages. When you re-start the Lesson
Builders, any pages defined with URLs will be reloaded from the
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