Efficiently invert bitmap on Android

gistfile1.java

	public Bitmap invert(Bitmap src)
	{ 
		int height = src.getHeight();
		int width = src.getWidth();    

		Bitmap bitmap = Bitmap.createBitmap(width, height, Bitmap.Config.ARGB_8888);
		Canvas canvas = new Canvas(bitmap);
		Paint paint = new Paint();
		
		ColorMatrix matrixGrayscale = new ColorMatrix();
		matrixGrayscale.setSaturation(0);
		
		ColorMatrix matrixInvert = new ColorMatrix();
		matrixInvert.set(new float[]
		{
			-1.0f, 0.0f, 0.0f, 0.0f, 255.0f,
			0.0f, -1.0f, 0.0f, 0.0f, 255.0f,
			0.0f, 0.0f, -1.0f, 0.0f, 255.0f,
			0.0f, 0.0f, 0.0f, 1.0f, 0.0f
		});
		matrixInvert.preConcat(matrixGrayscale);
		
		ColorMatrixColorFilter filter = new ColorMatrixColorFilter(matrixInvert);
		paint.setColorFilter(filter);
		
		canvas.drawBitmap(src, 0, 0, paint);
		return bitmap;
	}