UNITY NGUI IPHONEX完美适配

苹果的IphoneX新增一个安全区的概念，如下图

图中绿色区域为安全区，所有可交互的组件全部放在安全区内，只有背景可以延伸出去，达到全面屏的效果

我们适配IphoneX采用NGUI通用的锚点去适配。默认的NGUI屏幕适配方案不支持安全区这个概念，我在NGUI每个继承UIRect的组件下新增一个Bool变量InSafeArea，这个变量如果为True则表示这个组件是放置在安全区内的，如果为false则表示这个组件是全屏的，一般为True，只有背景图才需要去掉这个勾

原理：

所有的NGUI锚点的适配最终都会调用NGUITools.GetSides这个方法，这个方法实际上是NGUI为Camera写的扩展方法，如下，新增了一个inSafeArea参数，备注内是我新增的

	static public Vector3[] GetSides (this Camera cam, float depth, Transform relativeTo, bool inSafeArea = true)
	{
#if UNITY_4_3 || UNITY_4_5 || UNITY_4_6 || UNITY_4_7
		if (cam.isOrthoGraphic)
#else
		if (cam.orthographic)
#endif
		{
            // for iphonex by xiaobai
            float xOffset = 1f;
            float yOffset = 1f;
#if UNITY_IOS
            //iphone x 适配
            if (SystemInfo.deviceModel.Contains("iPhone10,3") || SystemInfo.deviceModel.Contains("iPhone10,6") && inSafeArea)
            {
                xOffset = 734f / 812f;
                yOffset = 340f / 375f;
            }
#elif UNITY_EDITOR
            //测试代码
            if (inSafeArea)
            {
                Vector2 ssize = screenSize;
                if (ssize.x == 1624f && ssize.y == 750f)        //自动识别
                {
                    xOffset = 734f / 812f;
                    yOffset = 340f / 375f;
                }
            }
#endif
            // end for iphonex by xiaobai
            float os = cam.orthographicSize;
			float x0 = -os * xOffset;
			float x1 = os * xOffset;
			float y0 = -os * yOffset;
			float y1 = os;

			Rect rect = cam.rect;
			Vector2 size = screenSize;
			float aspect = size.x / size.y;
			aspect *= rect.width / rect.height;
			x0 *= aspect;
			x1 *= aspect;

			// We want to ignore the scale, as scale doesn't affect the camera's view region in Unity
			Transform t = cam.transform;
			Quaternion rot = t.rotation;
			Vector3 pos = t.position;

			mSides[0] = rot * (new Vector3(x0, 0f, depth)) + pos;
			mSides[1] = rot * (new Vector3(0f, y1, depth)) + pos;
			mSides[2] = rot * (new Vector3(x1, 0f, depth)) + pos;
			mSides[3] = rot * (new Vector3(0f, y0, depth)) + pos;
		}
		else
		{
			mSides[0] = cam.ViewportToWorldPoint(new Vector3(0f, 0.5f, depth));
			mSides[1] = cam.ViewportToWorldPoint(new Vector3(0.5f, 1f, depth));
			mSides[2] = cam.ViewportToWorldPoint(new Vector3(1f, 0.5f, depth));
			mSides[3] = cam.ViewportToWorldPoint(new Vector3(0.5f, 0f, depth));
		}
		
		if (relativeTo != null)
		{
			for (int i = 0; i < 4; ++i)
				mSides[i] = relativeTo.InverseTransformPoint(mSides[i]);
		}
		return mSides;
	}

原理是如果检测到机型为iphonex，并且锚点限制在安全区内，就自动将屏幕大小缩小为安全区大小，否则就全屏。为了方便测试 在编辑器下，设置分辨率为1624x750就可以方便的看到iphonex的效果了

这段代码只展示原理，具体如何去应用，还需要改动UIRect和UIRectEditor的相关方法