Find Edges Filter in Flash AS 3?

Question

I've been scrubbing though google trying to get up to speed
with AS3, and with a particular job/problem to solve. I need to
take a dynamic image, desaturate it, and create the Photoshop
effect of the Find Edges filter. Does this seem even vaguely
possible? I've got the desaturate part working... no thanks to my
own brains.

Answer 1

Since it's possible in AS2 it's certainly possible in 3.
Here's a little
sample that will do vertical edge enhancement... All you need
is to import
a bitmap into the library then give it a linkage id to feed
to the
loadBitmap method. Hopefully, this is enough to get you
started.
If you want to do it the hard way it's easy to write a
convolution kernel,
it just won't be as fast. Google 'Sobel' which is the edge
detection
algorithm used by Photoshop.
import flash.filters.ConvolutionFilter;
import flash.display.BitmapData;
var filter:ConvolutionFilter = new ConvolutionFilter(3, 3,
[-1,0,1,-2,0,2,-1,0,1]);
var bit:BitmapData =
BitmapData.loadBitmap("bitmapLinkageID");
var mc:MovieClip = this.createEmptyMovieClip("mc",
this.getNextHighestDepth());
bit.applyFilter(bit, bit.rectangle, new Point(0,0), filter);
mc.attachBitmap(bit, this.getNextHighestDepth());
Dave -
Head Developer
www.blurredistinction.com
Adobe Community Expert
http://www.adobe.com/communities/experts/