MACROMEDIA FLASH 8-USING FLASH - Runtime Bitmap Caching Movie Clip and Button Symbols

Runtime bitmap caching movie clip and button symbols 81
To edit a movie clip symbol using 9-slice scaling:
1. Enter symbol-editing mode by doing one of the following:
■ Select an instance of the symbol on the Stage and right-click (Windows) or Control-
click (Macintosh), and select Edit from the context menu.
■ Select the symbol in the Library and right-click (Windows) or Control-click
(Macintosh), and select Edit from the context menu.
■ Double-click the symbol in the Library.
The slice-9 guides appear.
2. Move the pointer over any of the four guides in the workspace to change the pointer to the
horizontal or vertical guide pointers that indicate that a drag operation will move the
position of the guide. Drag and release the pointer.
The new position of the guide is updated in the library preview for the symbol.
Runtime bitmap caching movie clip and
button symbols
Runtime bitmap caching lets you optimize playback performance by specifying that a static
movie clip (for example, a background image) or button symbol be cached as a bitmap at
runtime. Caching a movie clip as a bitmap prevents Flash Player from having to continually
redraw the image, which provides a significant improvement in playback performance.
For example, when creating animations with a complex background, you can create a movie
clip for the background. The background is rendered as a bitmap stored at the current screen
depth. It can be drawn very quickly, letting the animation play both faster and more
smoothly, because the background doesn’t need to continually be redrawn.
Without the use of bitmap caching, the animation might play back too slowly, because the
background continually would be redrawn from vector data.
Bitmap caching lets you use a movie clip and “freeze” it in place automatically. If a region
changes, Flash uses vector data to update the bitmap cache. This minimizes the number of
redraws that Flash Player must perform, and provides smoother, faster playback performance.
Only use runtime bitmap caching on static, complex movie clips in which the position, but
not the content, of the movie clip changes on each frame in an animation. You can only
observe on complex-content movie clips the playback or runtime performance improvement
in using runtime bitmap caching. You will not see the performance benefit of runtime bitmap
caching when creating simple movie clips.