Android：獲取灰色圖片

public static final Bitmap getImageViewGreyBitmap(Bitmap bitmap) {
		int width = bitmap.getWidth();
		int height = bitmap.getHeight();
		Bitmap greyBitmap = Bitmap.createBitmap(width, height, Bitmap.Config.ARGB_8888);
		Canvas canvas = new Canvas(greyBitmap);
		Paint paint = new Paint();
		ColorMatrix colorMatrix = new ColorMatrix();
		colorMatrix.setSaturation(0);
		ColorMatrixColorFilter colorMatrixFilter = new ColorMatrixColorFilter(colorMatrix);
		paint.setColorFilter(colorMatrixFilter);
		canvas.drawBitmap(bitmap, 0, 0, paint);
		return greyBitmap;
	}