Question

Let´s say I have a bitmap with 3 colors: red, green and blue (not mixed)

What if I wanted to make a bitmap of the red part of the first bitmap?

I´d like to take the red pixels from first bitmap (and its positions), and make another bitmap.

Is that possible?

Answer 1

You can use BitmapData.copyChannel() to copy a single channel’s color information into a new BitmapData object.

Something like this (untested):

//myBitmap is the source bitmap
var oldBMD:BitmapData = myBitmap.bitmapData;
var newBMD:BitmapData = new BitmapData(oldBMD.width,oldBMD.height,true,0);
oldBmd.copyChannel(newBMD, null, null, BitmapDataChannel.RED, BitmapDataChannel.RED);
var newBitmap:Bitmap = new Bitmap(newBMD);