android 将圖檔變為圓角

/** 
* 圖檔變為圓角 
* @param bitmap:傳入的bitmap 
* @param pixels：圓角的度數，值越大，圓角越大 
* @return bitmap:加入圓角的bitmap 
*/ 
public static Bitmap toRoundCorner(Bitmap bitmap, int pixels) { 
    if(bitmap == null) {
        return null; 
    }
    Bitmap output = Bitmap.createBitmap(bitmap.getWidth(), bitmap.getHeight(), Config.ARGB_8888); 
    Canvas canvas = new Canvas(output); 
    final int color = ; 
    final Paint paint = new Paint(); 
    final Rect rect = new Rect(, , bitmap.getWidth(), bitmap.getHeight()); 
    final RectF rectF = new RectF(rect); 
    final float roundPx = pixels; 
    paint.setAntiAlias(true); 
    canvas.drawARGB(, , , ); 
    paint.setColor(color); 
    canvas.drawRoundRect(rectF, roundPx, roundPx, paint); 
    paint.setXfermode(new PorterDuffXfermode(Mode.SRC_IN)); 
    canvas.drawBitmap(bitmap, rect, rect, paint); 
    return output; 
}