Actionscript convert background to Transparent

Question

The purpose of the function is to covert the background to transparent and then return the bitmapdata, but it seems it do not work. The code is following:

 private function transparentConverter( source:BitmapData, threshold:Number = 0.1 ):BitmapData
  {
   var bitmapData:BitmapData = new BitmapData( source.width, source.height, true, 0x00000000  );
   bitmapData.lock();
   var color:uint = source.getPixel( 0, 0 );

   var x:uint, y:uint;
   for ( y = 0; y < source.height; y++ )
   {
    for ( x = 0; x < source.width; x++ )
    {
     var c1:uint = source.getPixel( x, y );
     var c2:uint = color;
     var rx:uint = Math.abs((( c1 & 0xff0000 ) >> 16 ) - (( c2 & 0xff0000 ) >> 16 ));
     var gx:uint = Math.abs((( c1 & 0xff00) >> 8 ) - (( c2 & 0xff00 ) >> 8 ));
     var bx:uint = Math.abs(( c1 & 0xff ) - ( c2 & 0xff ));

     var dist:uint = Math.sqrt( rx*rx + gx*gx + bx*bx );

     if ( dist <= threshold )
     {
      bitmapData.setPixel32( x, y, 0x00000000 );
     }else
      {
       bitmapData.setPixel32( x, y, c1 );
      }
    }
   }
   bitmapData.unlock();
   return bitmapData;
  }

Please advice.

Answer 1

answered here already :

http://stackoverflow.com/questions/608087/flex-actionscript-white-to-transparent/608520#608520

Answer 2

Hi, Theo, the function seems can run, but take some time, however no bitmapdata return.

I receive the bitmpadata by the following code:

bitmapData = transparentConverter( bitmapData );

var bitmap:Bitmap = new Bitmap( bitmapData );

image1.source = bitmap;

The image do not appear.

And also, I can trace( c1 ), and I get a long list of data. Thanks for your response.

Answer 3

Can you try this :

// This bitmapData should be defined for real, wherever you get that from ...
var source:BitmapData;  

if(source == null)
   trace("The source cannot be empty");

// Here you get the transformed BitmapData
var destination:bitmapData = transparentConverter( source );

// You apply it to a Bitmap in order to visualize it
var viewBitmap:Bitmap = new Bitmap(destination);

// You add the Bitmap to the stage so you can see it
addChild(viewBitmap);

Answer 4

Theo, thanks for your effeort. I think the problem is the fuctions takes too logn to run. After I try your script, a warning messages come out. It said the progam takes more than 15 seconds to run and told me to stop running.

I think the function should be OK, but, maybe, not quite practical.

Theo, thank for your time and advice again.

I think the question can be closed.