Frequently Asked Questions Frequently Asked QuestionsQ:
Is there any easy way to use your other products to make an image map (so that the user can click on different parts of an image in OmniWeb to jump to different links...)?
A:
Diagram!2 and WetPaint can both be used to create images for image maps.
With Diagram!, you can use the position inspector to find coordinates. Select the object, raise the Position inspector, and the position will be displayed in the lower right hand corner of the inspector. The "origin" is the upper right hand corner. When you're ready to create the gif, do a Save To...eps from your Diagram document , and use OmniImage to convert to gif format (OmniImage is supplied with OmniWeb and is downloadable from the Lighthouse Design web site).
Note: To get Diagram's inspector to display in points, you may need to set your Measurement Units in NEXTSTEP Preferences to Points.
WetPaint is even better for doing image maps. Click the mouse on the image and drag slightly. The mouse coordinates are shown at the top of the window which makes it easy to pinpoint the coordinates you will use in your image map.
In this section we walk through the steps needed to get an initial image map up and running.
First, create or locate a usable image.
There are a number of image creation and editing programs that will work nicely; the important thing is that the image ends up in GIF format (GifOmatic, from interpersonal-computing GmbH, info@interpc.de, is a great tool for this)
A common scheme for an image map is a collection of rectangles and circles, each containing a short text description of some piece of information or some information server; interconnections are conveyed through lines or arcs. Try to keep the individual items in the map spaced out far enough so a user will clearly know what he or she is clicking on.
Second, create an image map file.
Here is what an image map file looks like:
default /X11/mosaic/public/none.html
rect http://cui_www.unige.ch/w3catalog 15,8 135,39
rect gopher://rs5.loc.gov/11/global 245,86 504,143
rect http://nearnet.gnn.com/GNN-ORA.html 117,122 175,158
The format is fairly straightforward. The first line specifies the default response (the file to be returned if the region of the image in which the user clicks doesn't correspond to anything).
Subsequent lines specify rectangles in the image that correspond to arbitrary URLs -- for the first of these lines, the rectangle specified by 15,8 (x,y of the upper-left corner, in pixels) and 135,39 (lower-right corner) corresponds to URL http://cui_www.unige.ch/w3catalog.
You need to find the upper-left and lower-right corners of a rectangle for each information resource in your image map. A good tool to use for this is xv.
It doesn't matter where you put your map file or what you name it. For the purposes of this example, let's assume it's called /foo/sample.map.
Third, tell your server about your image map file.
You do this by adding a file to the server's conf/imagemap.conf file. The line looks like this:
sample : /foo/sample.map
... where sample is the symbolic name for your image map and /foo/sample.map is the actual name of your map file.
Fourth, create an HTML document that contains your map image.
An example follows:
Click on the information resource you wish to see:
<P><A HREF="http://machine/htbin/imagemap/sample"> <IMG SRC="sample.gif" ismap> </A> </P>
Note:
* machine is the name of the machine on which your HTTP server resides.
* sample is the symbolic name of your image map (from above).
* sample.gif is the name of your image (assuming, of course, that it's in the same directory on your server as the HTML file).
Fifth, try it out! Load the HTML file, look at the inlined image, click somewhere, and see what happens.
You can serve as many image maps from a single server as you want. Just add lines to conf/imagemap.conf pointing to each image map file you create.
There is also a shareware application called WebMapper, which is an imagemap tool for NEXTSTEP, available from next-ftp.peak.org or eclipse.its.rpi.edu
