添加倒影 Drawable轉bitmap工具類

public class MyImgView {

	/**
	 * 添加倒影，原理，先翻轉圖片，由上到下放大透明度
	 * 
	 * @param originalImage
	 * @return
	 */
	public static Bitmap createReflectedImage(Bitmap originalImage) {
		final int reflectionGap = 4;

		int width = originalImage.getWidth();
		int height = originalImage.getHeight();

		Matrix matrix = new Matrix();
		matrix.preScale(1, -1);

		Bitmap reflectionImage = Bitmap.createBitmap(originalImage, 0,
				height / 2, width, height / 2, matrix, false);

		Bitmap bitmapWithReflection = Bitmap.createBitmap(width,
				(height + height / 2), Config.ARGB_8888);

		Canvas canvas = new Canvas(bitmapWithReflection);
		canvas.drawBitmap(originalImage, 0, 0, null);
		Paint defaultPaint = new Paint();
		canvas.drawRect(0, height, width, height + reflectionGap, defaultPaint);
		canvas.drawBitmap(reflectionImage, 0, height + reflectionGap, null);

		Paint paint = new Paint();
		LinearGradient shader = new LinearGradient(0,
				originalImage.getHeight(), 0, bitmapWithReflection.getHeight()
						+ reflectionGap, 0x70ffffff, 0x00ffffff, TileMode.CLAMP);
		paint.setShader(shader);
		paint.setXfermode(new PorterDuffXfermode(Mode.DST_IN));
		canvas.drawRect(0, height, width, bitmapWithReflection.getHeight()
				+ reflectionGap, paint);

		return bitmapWithReflection;
	}
	//drawable 類型轉化爲bitmap
	public static Bitmap drawableToBitmap(Drawable drawable) {

		Bitmap bitmap = Bitmap
				.createBitmap(
						drawable.getIntrinsicWidth(),
						drawable.getIntrinsicHeight(),
						drawable.getOpacity() != PixelFormat.OPAQUE ? Bitmap.Config.ARGB_8888
								: Bitmap.Config.RGB_565);
		Canvas canvas = new Canvas(bitmap);
		drawable.setBounds(0, 0, drawable.getIntrinsicWidth(), drawable
				.getIntrinsicHeight());
		drawable.draw(canvas);
		return bitmap;
	}

}