ACTIONSCRIPT 3 Developer’s Guide en

ACTIONSCRIPT 3.0 DEVELOPER’S GUIDE
Working with bitmaps
Color channel Commonly, colors are represented as a mixture of a few basic colors—usually (for computer graphics)
red, green, and blue. Each basic color is considered a color channel; the amount of color in each color channel, mixed
together, determines the final color.
Color depth Also known as bit depth, this refers to the amount of computer memory that is devoted to each pixel,
which in turn determines the number of possible colors that can be represented in the image.
Pixel The smallest unit of information in a bitmap image—essentially a dot of color.
Resolution The pixel dimensions of an image, which determines the level of fine-grained detail contained in the
image. Resolution is often expressed in terms of width and height in number of pixels.
RGB color A color scheme where each pixel’s color is represented as a mixture of red, green, and blue color values.
The Bitmap and BitmapData classes
Flash Player 9 and later, Adobe AIR 1.0 and later
The main ActionScript 3.0 classes for working with bitmap images are the Bitmap class, which is used to display
bitmap images on the screen, and the BitmapData class, which is used to access and manipulate the raw image data of
a bitmap.
More Help topics
flash.display.Bitmap
flash.display.BitmapData
Understanding the Bitmap class
Flash Player 9 and later, Adobe AIR 1.0 and later
As a subclass of the DisplayObject class, the Bitmap class is the main ActionScript 3.0 class used for displaying bitmap
images. These images may have been loaded via the flash.display.Loader class or created dynamically using the
Bitmap() constructor. When loading an image from an external source, a Bitmap object can only use GIF, JPEG, or
PNG format images. Once instantiated, the Bitmap instance can be considered a wrapper for a BitmapData object that
needs to be rendered to the Stage. Because a Bitmap instance is a display object, all the characteristics and functionality
of display objects can be used to manipulate a Bitmap instance as well. For more information about working with
display objects, see “Display programming” on page 151.
Pixel snapping and smoothing
Flash Player 9 and later, Adobe AIR 1.0 and later
In addition to the functionality common to all display objects, the Bitmap class provides some additional features that
are specific to bitmap images.
The pixelSnapping property of the Bitmap class determines whether or not a Bitmap object snaps to its nearest pixel.
This property accepts one of three constants defined in the PixelSnapping class: ALWAYS, AUTO, and NEVER.
The syntax for applying pixel snapping is as follows:
myBitmap.pixelSnapping = PixelSnapping.ALWAYS;
Last updated 6/6/2012
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