Webmaster Forum / Flash / General Flash Topics / December 2008

Barring finding a method to do this, I hacked together a solution.

First, I found the bounds of all transparent pixels using getColorBoundsRect.

Next I iterated from the top-down until I found the first line with only
transparent pixels to revise the top edge

Finally I iterated from the bottom-up until finding the bottom line of only
transparent pixels to revise the bottom edge.

I was able to compensate like as such because I know that the rectangle is not
impeded from the sides at any point, otherwise I would have had to find the
left and right edges as well.

I feel like there should be an easier way (and also a less processor-intensive
way) to do this.

var clBD:BitmapData = new BitmapData(735,600,true, 0x00FFFFFF);
    clBD.draw(contentLoader.content);
    var transparentRect:Rectangle =
clBD.getColorBoundsRect(0xFF000000,0x00000000,true);
   
    var top:Number = transparentRect.y;
    var bottom:Number = transparentRect.y + transparentRect.height;
   
    for(var i:uint = transparentRect.y ; i < bottom ; i++){
        for(var j:uint = transparentRect.x ; j < (transparentRect.x +
transparentRect.width - 1) ; j++){
            if((clBD.getPixel32(j,i) >> 24 & 0xFF) > 50){
                top++;
                j = transparentRect.x + transparentRect.width;
            }else if(j == (transparentRect.x + transparentRect.width - 2)){
                i = bottom;
                j = transparentRect.x + transparentRect.width;
            }
        }
    }
   
    for( i = (transparentRect.y + transparentRect.height) ; i > top ; i -- ){
       
        for( j = transparentRect.x ; j < (transparentRect.x + transparentRect.width
- 1) ; j++){
            if((clBD.getPixel32(j,i) >> 24 & 0xFF) > 10){
                bottom -- ;
                j = transparentRect.x + transparentRect.width;
            }else if(j == (transparentRect.x + transparentRect.width - 2)){
                i = top;
                j = transparentRect.x + transparentRect.width;
            }
        }
       
    }
   
    clBD.dispose();

Wow, 3 months and no-one can find a better way to do this?