Flash Introduction
CHAPTER 1
FLASH INTRODUCTION
Three most important aspects of Flash:
1. Vector-based
graphics
2. Streaming
3. Compression
Vector Based Graphics
Traditionally, images on the Web have been bitmaps i.e.
images that are made up of pixels, or tine colored dots. Since each pixel adds to the file size of the
image, you have to walk a fine line between quality and file sizes. Also, when a bitmap image is resized it an
deteriorate in quality.
Since one of the main functions of Flash is creating drawing
objects, it is vital that it can do this in an efficient and high-quality
way. It achieves this by using a
vector-based system for producing graphics, rather than a pixel-based one. A vector-based system is one where objects,
lines and fills are created using mathematical equations. This has two considerable advantages:
1. Vector-based
images are usually a lot smaller in file size than their bitmap counterparts.
2. Vector-based
images lose very little image quality when they are resized.
Streaming:
The end product created by Flash (called a Flash movie) can
be either a few seconds long or several minutes. With the latter there could be problems with
downloading time over the Web. Flash
overcomes this problem with a technique called streaming. This feeds information to the browser as it
needs it to play the movie, without having to wait for the whole thing to be
downloaded to get started.
Compression:
Most images on the Web are compressed in one way or
another. GIFs, JPEGs, and PNGs all use
various forms of compression to decrease their file size. In the majority of case this has at worst
only a minimal effect on the final image.
Flash uses a variety of sophisticated compression
techniques, for both images and sounds.
The technical side of this is best left to the experts but there are
some preference settings that can be used to determine various compression
settings. These will be looked in the
relevant chapters.
Web authoring:
Although flash movies can be output through a variety of
devices, their main function is in the production of Web pages. However, there is one important point that
should be remembered in relation to this:
Flash movies have to be incorporated into HTML documents to enable them
to be displayed on the Web. This means
you have to create HTML pages for your site and then insert the relevant Flash
movies. Lukily, Flash has a facility for
producing HTML files that incorporate Flash moives. The end result looks complicated, but Flash
takes care of most of this behind the
scenes.
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