Bilinear Resampling, ShaderJob, Pixel Bender And Flash Player

            // source in this example is a DisplayObject
            var temp:BitmapData = new BitmapData( sourceWidth, sourceHeight );
            temp.draw( source );
 
            var output:BitmapData = new BitmapData( outputWidth, outputHeight );
 
            var matrix:Matrix = new Matrix();
            matrix.scale( outputWidth / sourceWidth, outputHeight / sourceHeight );
 
            output.draw( temp, matrix, null, null, null, true );
            temp.dispose();

/**
 * Copyright 2009 (c) , Brooks Andrus
 * 
 * Permission is hereby granted, free of charge, to any person
 * obtaining a copy of this software to deal in the Software without
 * restriction, including without limitation the rights to use,
 * copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following
 * conditions:
 *
 * The above copyright notice and this permission notice shall be
 * included in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
 * OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
 * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
 * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
 * OTHER DEALINGS IN THE SOFTWARE.
 * 
 */
package com.brooksandrus.utils
{
    import flash.display.BitmapData;
    import flash.display.DisplayObject;
    import flash.display.Shader;
    import flash.display.ShaderJob;
 
    public class BilinearResample
    {
        [Embed ( source="../../../../assets/bilinearresample.pbj", mimeType="application/octet-stream" ) ]
        private var BilinearScaling:Class;
 
        public function BilinearResample()
        {
            super();
        }
 
        public function resampleBitmap( input:BitmapData, desiredWidth:int, desiredHeight:int, cleanup:Boolean = true ):BitmapData
        {
            var aspectRatio:Number = input.width / input.height;
 
            var factor:Number = Math.max( input.width / desiredWidth, input.height / desiredHeight );
 
            // create and configure a Shader object
            var shader:Shader = new Shader();
            shader.byteCode = new BilinearScaling(); // instantiate embedded Pixel Bender bytecode
            shader.data.src.input = input; // supply the shader with BitmapData it will manipulate
            shader.data.scale.value = [factor]; // scale factor. shader params are all stored in arrays.
 
            var outputWidth:int;
            var outputHeight:int;
 
            // determine output bitmap dimensions
            if ( input.width > input.height )
            {
                outputWidth = desiredWidth;
                outputHeight = desiredWidth / aspectRatio;
            }
            else
            {
                outputWidth = desiredHeight * aspectRatio;
                outputHeight = desiredHeight;
            }
 
            // create a bitmap - our shader will return its data (an image) to this bitmap
            var output:BitmapData = new BitmapData( outputWidth, outputHeight );
 
            // shader jobs are wicked cool
            var job:ShaderJob = new ShaderJob();
            job.target = output; // ShaderJob returns to this object
            job.shader = shader; // The Shader assigned to this job
            job.start( true ); // true flag runs the job synchronously.
 
            if ( cleanup )
            {
                input.dispose();
            }
 
            return output;
        }
 
        public function resampleDisplayObject( source:DisplayObject, desiredWidth:int, desiredHeight:int ):BitmapData
        {
            var aspectRatio:Number = source.width / source.height;
 
            var factor:Number = Math.max( source.width / desiredWidth, source.height / desiredHeight );
 
            var input:BitmapData = new BitmapData( source.width, source.height, true );
            input.draw( source );
 
            // configure the shader
            var shader:Shader = new Shader();
            shader.byteCode = new BilinearScaling();
            shader.data.src.input = input;
            shader.data.scale.value = [factor]; // scale factor. shader params are all stored in arrays.
 
            var outputWidth:int;
            var outputHeight:int;
 
            if ( input.width > input.height )
            {
                outputWidth = desiredWidth;
                outputHeight = desiredWidth / aspectRatio;
            }
            else
            {
                outputWidth = desiredHeight * aspectRatio;
                outputHeight = desiredHeight;
            }
 
            var output:BitmapData = new BitmapData( outputWidth, outputHeight );
 
            var job:ShaderJob = new ShaderJob();
            job.target = output;
            job.shader = shader;
            job.start( true ); // true flag runs the job synchronously.
 
            input.dispose();
 
            return output;
        }
    }
}