ACTIONSCRIPT 3 Developer’s Guide en

ACTIONSCRIPT 3.0 DEVELOPER’S GUIDE
Working with bitmaps
import flash.display.Bitmap;
import flash.display.BitmapData;
var myParentSquareBitmap:BitmapData = new BitmapData(100, 100, false, 0x00ff3300);
var myClonedChild:BitmapData = myParentSquareBitmap.clone();
var myParentSquareContainer:Bitmap = new Bitmap(myParentSquareBitmap);
this.addChild(myParentSquareContainer);
var myClonedChildContainer:Bitmap = new Bitmap(myClonedChild);
this.addChild(myClonedChildContainer);
myClonedChildContainer.x = 110;
The copyPixels() method is a quick and easy way of copying pixels from one BitmapData object to another. The
method takes a rectangular snapshot (defined by the sourceRect parameter) of the source image and copies it to
another rectangular area (of equal size). The location of the newly “pasted” rectangle is defined within the destPoint
parameter.
The copyChannel() method samples a predefined color channel value (alpha, red, green, or blue) from a source
BitmapData object and copies it into a channel of a destination BitmapData object. Calling this method does not affect
the other channels in the destination BitmapData object.
The draw() and drawWithQuality() methods draw, or render, the graphical content from a source sprite, movie clip,
or other display object on to a new bitmap. Using the matrix, colorTransform, blendMode, and destination
clipRect parameters, you can modify the way in which the new bitmap is rendered. This method uses the vector
renderer in Flash Player and AIR to generate the data.
When you call draw() or drawWithQuality(), you pass the source object (sprite, movie clip, or other display object)
as the first parameter, as demonstrated here:
myBitmap.draw(movieClip);
If the source object has had any transformations (color, matrix, and so forth) applied to it after it was originally loaded,
these transformations are not copied across to the new object. If you want to copy the transformations to the new
bitmap, then you need to copy the value of the transform property from the original object to the transform property
of the Bitmap object that uses the new BitmapData object.
Compressing bitmap data
Flash Player 11.3 and later, AIR 3.3 and later
The flash.display.BitmapData.encode() method lets you natively compress bitmap data into one of the
following image compression formats:
PNG - Uses PNG compression, optionally using fast compression, which emphasizes compression speed over file
size. To use PNG compression, pass a new flash.display.PNGEncoderOptions object as the second parameter
of the BitmapData.encode() method.
JPEG - Uses JPEG compression, optionally specifying image quality. To use JPEG compression, pass a new
flash.display.JPEGEncoderOptions object as the second parameter of the BitmapData.encode() method.
JPEGXR - Uses JPEG Extended Range (XR) compression, optionally specifying color channel, lossy, and entropy
settings. To use JPEGXR compression, pass a new flash.display.JPEGXREncoderOptions object as the second
parameter of the BitmapData.encode() method.
Last updated 6/6/2012
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