Flash 8: Projects for Learning Animation and Interactivity

Chapter 10. Compositing and Bitmap Effects

In this chapter

Runtime Bitmap Caching

Bitmap Filter Effects

Blend Modes

Flash 8 introduced an entirely new approach to compositing visual assets at runtime that has dramatically increased artistic options available to Flash users. Traditional techniques (such as manipulating movie clip opacity, using the PNG file format for bitmap transparency, and pre-creating graphic, movie clip, and button states) are frequently still useful and even preferred. However, new bitmap rendering routines now offer new ways of accomplishing similar goals, often yielding better results.

Runtime Bitmap Caching

Many people, when hearing Flash 8’s new compositing features described as bitmap rendering techniques, have a similar reaction: understandably, they think that these features are applicable only to imported JPEG, PNG, GIF, or other bitmap file formats. However, one of the best overall features of Flash 8 is its ability to treat movie clips—including vector-only movie clips—like bitmaps, for the purposes of compositing. This is a feature known as runtime bitmap caching.

You may be asking yourself why you would want to convert your beautifully sharp vectors into pixels. Fortunately, that’s not exactly what’s happening. It’s true that the Flash Player will handle the movie clip as if it were a bitmap, but only when instructed to do so. Any vectors remain editable, and their appearance remains crisp and clean. Also, it’s an automatic process that typically ...