[ Pobierz całość w formacie PDF ]
.The best way to use an imagemap is as a clickable menu bar or some other easy-to-recognizeinterface element.The point isn't really to see how graphicalyou can make your Web pages-just how intuitive.Remember that image maps are usually little more than biggraphics files.Ultimately, the key to graphics on the Webis keeping them small.Even if your image map is incredibly attractive,users will be annoyed if they have to wait many minutes for theirfour possible choices to download to their browsers.Use all thetips in Chapter 9 to keep your graphicas small as possible, and use image maps only to enhance usability.Image maps require redundant text links.Unless youplan to leave out everyone who can't view your graphics, you needto create text links that do everything that your image map does.Remember that with clickable graphics, the ALTattribute takes care of the problem.The ALTattribute doesn't work for image maps, because a single imagemap graphic can have many links, so you need to create an identicaltext link on your page for every hot zone link in your image map.Stick to normal shapes whenever possible.Rulesare made to be broken, but in general, you should try to be conservativewith your image maps (see fig.12.7).A graphic that looks asthough it has rectangular buttons should function as though ithas rectangular buttons.In other words, make your hot zones correspondlogically to the image map graphics.Random hot zones randomlyannoy users.Figure 12.7 : Some sites make it their business to use image maps that break the rules.This one doesn't.SummaryImage maps allow you to create hot zones in individual graphicsfiles.These hot zones point to different URLs, effectively turninga single graphic into a Web interface.By creating creative graphicsand pointing different sections of those graphics to pages inyour site, you can make it very easy for Web users to get aroundon your site.Image maps work in conjunction with your Web server, which mustbe running a special map server program.In such a case, you needto create a graphic and a map definition file.Fortunately, programsfor Windows, UNIX, and Macintosh exist to help you create thisdefinition file.In conjunction with your system administrator, you place the mapdefinition file in the correct directory on your Web server (mostoften in the /cgi-bin or/bin directory), and createa link to the image map on your Web page.Placing the image mapin your HTML document requires the same anchor and <IMG>tags, but you need to include the ISMAPattribute in the <IMG>tag.After you finish with all your tags, test your new image map.If all goes well, you'll have a new interface for your Web pages.You should consider some design rules.Basically, keep the graphicssmall and fairly standard, so that you don't annoy or confuseyour users.ReviewQuestionsWhy are the graphics discussed in this chapter called imagemaps?What three steps do you follow to create an image map?What file format is the map definition file saved in?Is it important to know what type of map server program yourWeb server is using? Why or why not?How do you find out where to store your map definition file?How many points are required for a rectangle in a map definitionfile? What is the maximum number of points that you can use fora polygon?True or false.You can create an image map without a map editingprogram.Which files must you create for an image map to work?Do the shapes (rect, poly, point, and so on) that you drawin a map editing program show up in the Web browser window? Whyor why not?Why is defining a default map definition redundant if youhave already defined a point?Aside from the URL to the map definition file, what informationdoes the Web browser send to the Web server? What does the designerdo to make this happen?ReviewExercisesCreate two different map definition files for the same graphic,one using the CERN method and one using NCSA.Compare the twodefinition files and notice the differences.Again create two different map definition files for the samegraphic, this time using all polygon shapes for one of the definitionsand all squares for the other definition.Compare the two definitionfiles.Are polygons considerably more complicated than standardshapes?Create a button bar (or menu bar) using a series of clickablegraphics.Then, create a similar button bar using an image map.Which takes more work? Which will take more time to download toa browser (i.e., which method takes up more drive space)?Use of this site is subject to certainCopyright (c) 1996-1998EarthWeb, Inc.All rights reserved.Reproduction in whole or in part in any form or medium without express written permission of EarthWeb is prohibited.Please read the.Contact with questions or comments.Copyright 1998 Macmillan Computer Publishing.All rights reserved
[ Pobierz całość w formacie PDF ]