Symbols and Instances

It's important to understand the relationship between shapes, symbols and instances. A shape is a single graphic on the stage. If you wanted to reuse it in your movie, you'd need to manually copy and paste it. If you make changes to a shape, those changes don't affect any copies of the shape you may have made. In other words, shapes behave the way you've probably come to expect of objects based on your experience in other applications.

One of the most useful features of Flash is that it allows you to easily and efficiently reuse elements in your movie, including graphic objects, buttons, sound clips, or even animations. In other words, you generally need to draw or import your artwork only once, even if the same or similar images are going to be used many times throughout your movie.

These reusable elements are called symbols, and they're stored in the Library. You can convert shapes into symbols after you've drawn them by selecting the shape and choosing Insert | Convert to Symbol on the menu. You can also create a new graphic as a symbol to start by choosing Insert | New Symbol on the menu.

In the new symbol dialog box, specify Graphic as the behavior.

You're now in symbol-editing mode. To return to the movie, click on Scene 1 in the movie navigation (to the left of the Leaf graphic icon). When you are back in Scene 1, your symbol will be in the Library, ready for use in the movie. Note: If you don't see the Library, select Window | Library from the menu.

A symbol can be considered a "master" graphic that is available to be used as many times within your movie as you want. Each copy of a symbol you pull out of the library and use in your movie is called an instance of that symbol.

The properties of each instance, such as color, size, perspective, and so forth can be changed without affecting the other instances of the symbol. But, changes to the master symbol do affect all of its instances.

What if you decide you need to have a unique and separate copy of a symbol? You can convert an instance of an existing symbol to a shape, which will allow you to edit it to a greater extent without affecting any other instances (copies) that were made from the original master symbol. This is called breaking apart the instance.

To break apart an instance of a symbol, select the instance on the stage. Choose Modify | Break Apart from the menu. This breaks the instance into its component graphic elements, and you can use the painting and drawing tools to modify these elements as desired. Once you've made your modifications, you can select the graphic and convert it to a new symbol.

There are many benefits to having symbols and instances: in addition to minimizing the developers' work, they also minimize file sizes as the final movie need only contain the master image.