ngui 分辨率 屏幕适配

 screen.width  按像素计算，和unity 的窗口有关

root.activeheight  NGUI真实大小

        static public float calWinScale(int winW, int winH, bool isFullScreen, float screenW, float screenH)

        {

            float mobileW = screenW - (isFullScreen ? 0 : widthGap);

            float mobileH = screenH - (isFullScreen ? 0 : heightGap);

            float _num = mobileH / winH;

            float acturyW = _num * winW;

            float acturyH = mobileH;

            if (acturyW > mobileW)

            {

                float _num2 = mobileW / acturyW;

                acturyW = mobileW;

                acturyH = acturyH * _num2;

            }

            float scY;

            scY = acturyH / winH;

            return scY;

        }