本地生成图片两种方法

一种sprite变为Textrue2d，存在本地 ，博客已经说过
一种相机截图 需要引入  System.Drawing.dll：
   public  void CaptureCamera(Camera camera)
    {
     
        Rect rect=new Rect(Screen.width * 0f, Screen.height * 0f, Screen.width * 1f, Screen.height * 1f);
        // 创建一个RenderTexture对象 
        RenderTexture rt = new RenderTexture((int)rect.width, (int)rect.height, 0);
   camera.targetTexture = rt;
        camera.Render();
       RenderTexture.active = rt;
        //Texture2D screenShot = new Texture2D((int)rect.width, (int)rect.height, TextureFormat.RGB24, false);
        Texture2D screenShot = new Texture2D((int)rect.width, (int)rect.height);
       screenShot.ReadPixels(rect,0, 0);// 注：这个时候，它是从RenderTexture.active中读取像素
        screenShot.Compress(true);
        screenShot.Apply();
 
         ui.TakePhoto.SetActive(true);
         Sprite pic = Sprite.Create(screenShot, new Rect(0, 0, screenShot.width, screenShot.height), new Vector2(0.5f,   0.5f));//后面Vector2就是你Anchors的Pivot的x/y属性值
         ui.Photo.GetComponent<UnityEngine.UI.Image>().sprite = pic;
 camera.targetTexture = null;
        //ps: camera2.targetTexture = null; 
        RenderTexture.active = null; // JC: added to avoid errors 
        Destroy(rt);
    byte[] bytes = screenShot.EncodeToPNG();
        i++;
        //filename = Application.persistentDataPath + "/Screenshot" + i.ToString()+".png";
        //创建一个新文件夹
        path = "/storage/emulated/0/AR课本";
        Directory.CreateDirectory(path);
        pathpic = "/storage/emulated/0/AR课本/截图";
        Directory.CreateDirectory(pathpic);
        filenameOld = pathpic + "/IMG_" + i.ToString() + ".png";
  File.WriteAllBytes(filenameOld, bytes);
}