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Compressing bitmap data

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.

You can use this feature for image processing as part of a server upload or download workflow.

The following example snippet compresses a BitmapData object using JPEGEncoderOptions:

// Compress a BitmapData object as a JPEG file.
var bitmapData:BitmapData = new BitmapData(640,480,false,0x00FF00);
var byteArray:ByteArray = new ByteArray();
bitmapData.encode(new Rectangle(0,0,640,480), new flash.display.JPEGEncoderOptions(), byteArray);