Basics of filtering display objects

One of the ways to add polish to an application is to add simple graphic effects. You can add a drop shadow behind a photo to create the illusion of 3-d, or a glow around a button to show that it is active. ActionScript 3.0 includes ten filters that you can apply to any display object or to a BitmapData instance. The built-in filters range from basic, such as the drop shadow and glow filters, to complex, such as the displacement map filter and the convolution filter.

Note: In addition to the built-in filters, you can also program custom filters and effects using Pixel Bender. See Working with Pixel Bender shaders.

Important concepts and terms

The following reference list contains important terms that you might encounter when creating filters:

Bevel
An edge created by lightening pixels on two sides and darkening pixels on the opposite two sides. This effect creates the appearance of a three-dimensional border. The effect is commonly used for raised or indented buttons and similar graphics.

Convolution
Distorting pixels in an image by combining each pixel's value with the values of some or all of its neighboring pixels, using various ratios.

Displacement
Shifting or moving pixels in an image to a new position.

Matrix
A grid of numbers used to perform certain mathematical calculations by applying the numbers in the grid to various values, then combining the results.