Flash Templates Tutorials - Symbols
Imagine some hypothetic Flash image that contains of many small elements. Do not think about what image that is just imagine some Flash image. Every element is described by some set of graphic primitives; therefore it occupies some disk space. Ten elements occupy ten times more space; hundred elements occupy hundred times more disk space and so on. Imagine by how many times the size of resulting swf file will increase.
Let us think this way. What is a big file? A repeated set of descriptions of exactly same elements - that is it. For many times we describe the same! Can't we just draw the image once and then link to it? We will save great amount of disk space, because the link to an image occupies incomparably smaller amount of disk space. Is this possible in Flash?
Of course it is. In this case, the description of the graphic element is placed in special repository, called the Library, and the element placed in the library is called a Symbol. Every symbol obtains unique name when created, and is assigned to a certain type. Now in the needed place on the workspace you can place the link to the symbol, creating the instance of the image.
Such method has other advantages. You can change all instances of one symbol just editing the symbol. When you are finished, Flash will update all instances automatically.
The only drawback is that you cannot edit selected instance as easy as regular graphics. But in many cases you can sacrifice that, right?
Moreover, you can change some parameters of the instance like its color, opacity, turn it or distort, change its size. However, it will remain an instance and if you will change the element in the library, the instance look will be refreshed too.
All files that you have imported to Flash document except for the swf files appear in the library. All of the images and movies, created in other programs also appear there and turn into symbols (except for swf files that are placed directly on the workspace and then are added to the library manually). It is very useful, because you can place the instances of imported image or sound as many times as you want without increasing the size of the movie.
If you plan to create animated images (movies) with Flash software, you cannot avoid working with symbols and libraries. Some types of animation can be applied only to the instances of the images that are stored in the library.