Additional Graphic Techniques
Several graphic techniques involving the GIF and JPEG file formats are critical to your Web graphic production work. They include progressive rendering, transparency, and animation. FrontPage can be used for progressive rendering and transparency, but you will need an additional tool to create animations such as Ulead's Gif Animator (http://gifanimator.frontpagelink.com).
This feature keeps a site visitor's visual attention while graphics are downloading from a server to a Web page. The concept is that the individual will see portions of the graphic until all of its binary data is loaded into the browser.
It's an effective method. If you prefer to have your images "pop" into a page, the downloading process appears to be smoother when progressive rendering is in place. You should learn progressive rendering techniques and make your own decisions based on personal and professional preferences.
Progressive rendering can be achieved in both the GIF and JPEG formats.
Most popular Web graphic applications support interlacing. When you save a Web page in FrontPage that contains GIF images, the Save Embedded Files dialog box, shown in Figure 44.5, appears. This dialog box enables you to rename the graphic file, change the image folder, set actions, or set various picture options.
Figure 44.5. The Save Embedded Files dialog box lets you rename any images in a Web page.
Clicking the Picture File Type button opens the Picture File Type dialog box (see Figure 44.6). This dialog box lets you specify the image format as JPEG, GIF, or PNG. It also lets you specify GIF images as interlaced if desired.
Figure 44.6. The Picture File Type dialog box lets you set several image format options.
An interlaced GIF will first appear fuzzy and then slowly clarify as the GIF data downloads to the Web browser.
If you view these images in the Preview window or in a browser on your local machine, you might not see the interlacing effect. Even large images will take almost no time to load from your local hard drive, so the interlacing effect isn't noticeable. To see the effect, load the image from a Web server over a slow Internet connection.
It's important to note that you cannot
As mentioned earlier in the chapter, the JPEG algorithm works by reducing rectangular sections of
Whereas interlaced GIFs first appear fuzzy and then get clearer, progressive JPEGs first appear blocky and blurry.
When serving progressive JPEGs at high speeds, the blurry effect is reduced or eliminated, improving the visual experience.
A JPEG image can be made into a progressive JPEG using FrontPage's Picture File Type dialog box. In this dialog box, you can specify the number of progressive passes. These
Standard GIFs and JPEGs scroll into place rather than render progressively. Some people prefer this look. Still, most usability studies and anecdotal information suggest that progressive rendering helps keep individuals on a page. Therefore, in many cases it's usually wise to progressively render your graphics.
Transparency can be described as an effect that places your graphic on a clear piece of tape. This means you can place that tape on a background and the background will show through the tape.
This is particularly effective when you're creating graphics that sit on a background—
The technique takes a little bit of time, patience, and an
Again, FrontPage can create transparent images, but your favorite Web graphics program is likely to have a helpful method by which to make an image transparent.
Only GIFs can be transparent. JPEG technology does not include a transparency option.
Assume that you want to place a text header image over a background texture. The text selection is ornate, with a lot of circular
Creating transparent GIF images can leave ragged edges around your image. To reduce the visibility of this edge, try to match the background color in the image to the background color on the Web page. This is something you'll want to do in the program you are designing your graphics in.
Another inherent feature of the GIF format is GIF animation. This very handy effect is actually an exploitation of GIF technology. This chapter
GIF animations are
FrontPage won't show the animation in Design view (it will only show you the first frame of the animation) but will show you the animation if you view the file in Preview view.