A Complete Guide to Web Design

Examples of XML Technology 449

XML

Examples of XML Technology

Web Design in a Nutshell, eMatter Edition

<AUDIO SRC="audio_file.wav" BEGIN="0s"/>

<SEQ>

<IMG SRC="image_1.jpg" BEGIN="0s"/>

<IMG SRC="image_2.jpg" BEGIN="3s"/>

<IMG SRC="image_3.jpg" BEGIN="6s"/>

</SEQ>

</PAR>

SMIL resources

The following resources provide useful information on the background, details,
and applications of SMIL.

W3C SMIL Recommendation
http://www.w3.org/AudioVideo/
A comprehensive set of links to SMIL information, including the SMIL 1.0
specification, which lists available SMIL tags and explains the rules and syntax
for their use.

Just
http://www.justsmil.com/SMIL.html
A clearinghouse for SMIL content, news, and discussion.

RealNetworks
http://www.real.com/
Many companies are producing tools so that developers can create SMIL
presentations today. SMIL’s most visible proponent is Real Networks. RealNet-
works has already released a SMIL creation wizard that guides developers
through the process of SMIL authoring, and the G2 media player, which
supports SMIL presentations. Their web site contains tutorials and tools that
will get you started with SMIL production.

Vector Graphics on the Web with XML

XML has typically been used to define the structure of text elements within a
document; however, many groups are working on ways in which it could be used
to define graphical information as well. In fact, there has been a flurry of activity
in the vector graphic arena in 1998, and the W3C has established a Scalable Vector
Graphics working group to develop a definitive standard.

Vector graphics are mathematical descriptions of the paths (or strokes) that make
up graphical images. These differ from bitmap (also known as “raster”) graphics,
which describe images in terms of a grid of colored pixels.

One of the advantages of vector graphics is that they describe points, lines, and
curves with mathematical functions, requiring much less data than describing a
shape pixel-by-pixel. With bandwidth a constant concern in web design, vector
graphics seem ideal for the transmission of graphical information. Another advan-
tage is that vector graphics are infinitely scalable without loss of quality for display
or output at any resolution. Bitmap images get fuzzy and pixellated when resized
dramatically.