Вы можете использовать BitmapData
для этого.
члены класса:
// flip vertically and shift by 100 (insert your canvas size)
private var reflect:Matrix = new Matrix(1, 0, 0, -1, 0, 100);
// instanciate BitmapData with 100x100 size (insert your canvas size),
// filled with black but with 100% transparancy, it's an
// ARGB value (0 == 0x00000000)
private var reflectionData:BitmapData = new BitmapData(100, 100, true, 0);
private var reflection:Bitmap = new Bitmap(reflectionData);
init:
// you might want to draw canvas already on startup
reflectionData.draw(canvas, reflect);
reflection.x = canvas.x;
reflection.y = canvas.y + canvas.height;
addChild(reflection);
для анимации / перерисовки
// clear to transparency
reflectionData.fillRect(reflectionData.rect, 0);
// draw the current canvas with matrix applied
reflectionData.draw(canvas, reflect);