Specifications

CHAPTER 4

Suspending background processing

To improve the performance of effects, you can disable background processing in your application for the

duration of the effect by setting the

suspendBackgroundProcessing property of the Effect to true. The

background processing that is blocked includes component measurement and layout, and responses to data

services for the duration of the effect.

Using the cachePolicy property

An effect can use bitmap caching in Flash Player to speed up animations. An effect typically uses bitmap caching

when the target component’s drawing does not change while the effect is playing.

The cachePolicy property of UIComponents controls the caching operation of a component during an effect.

The

cachePolicy property can have the following values:

CachePolicy.ON Specifies that the effect target is always cached.

CachePolicy.OFF Specifies that the effect target is never cached.

CachePolicy.AUTO Specifies that Flex determines whether the effect target should be cached. This is the default

value.

The cachePolicy property is useful when an object is included in a redraw region but the object does not change.

For more information about redraw regions, see “Understanding redraw regions” on page 83.

The

cachePolicy property provides a wrapper for the cacheAsBitmap property. For more information, see

“Using the cacheAsBitmap property” on page 83.

Improving rendering speed

The actual rendering of objects on the screen can take a significant amount of time. Improving the rendering times

can dramatically improve your application’s performance. Use the techniques in this section to help improve

rendering speed. In addition, use the techniques described in the previous section, “Improving effect perfor-

mance” on page 81, to improve effect rendering speed.

Setting movie quality

You can use the quality property of the wrapper’s <object> and <embed> tags to change the rendering of your

Flex application in Flash Player. Valid values for the

quality property are low, medium, high, autolow,

autohigh, and best. The default value is best.