Question

I need to flip a Bitmap horizontally. I tried setting its scaleX property to -1.0, and that modified the Bitmap in such a way that I can see only a small portion of it (flipped) on the left side, instead of the whole flipped Bitmap. Its x property remained 0. I tried the same thing using a transformation matrix, with the same results.

What am I doing wrong?

Answer 1

I posted a simple function to flip a bitmapdata object.
http://plasticsturgeon.com/2010/09/flipping-a-bitmapdata-image/

Here is the relevant code.

function flipBitmapData(original:BitmapData, axis:String = "x"):BitmapData
{
     var flipped:BitmapData = new BitmapData(original.width, original.height, true, 0);
     var matrix:Matrix
     if(axis == "x"){
          matrix = new Matrix( -1, 0, 0, 1, original.width, 0);
     } else {
          matrix = new Matrix( 1, 0, 0, -1, 0, original.height);
     }
     flipped.draw(original, matrix, null, null, null, true);
     return flipped;
}

If you want to flip the image in a bitmap, you can flip its bitmapdata property like so:

myBitmap.bitmapData = flipBitmapData(myBitmap.bitmapData, "x");

You can switch to a vertical flip by using “y”.