Unit implements mouse-holding screenshots to select area

private int capBeginX;
private int capBeginY;
private int capFinishX;
private int capFinishY;
 
public Image showImg;
 
// Use this for initialization
void Start () {
    
  }
  
  // Update is called once per frame
  void Update () {
    if ( (0)) {
      Vector3 mousePos = ;
      Vector2 beginPos = new Vector2 (, );
      capBeginX = (int);
      capBeginY = (int);
    }
 
    if ( (0)) {
      Vector3 mousePos = ;
      Vector2 finishPos = new Vector2 (, );
      capFinishX = (int);
      capFinishY = (int);
      //Recalculate the intercepted position      int capLeftX = (capBeginX < capFinishX) ? capBeginX : capFinishX;
      int capRightX = (capBeginX < capFinishX) ? capFinishX : capBeginX;
      int capLeftY = (capBeginY < capFinishY) ? capBeginY : capFinishY;
      int capRightY = (capBeginY < capFinishY) ? capFinishY : capBeginY;
 
      Rect rect=new Rect(capLeftX,capLeftY,capRightX,capRightY);
      StartCoroutine( Captrue (rect));
    }
  }
 
  IEnumerator Captrue(Rect rect){
 
    int t_width =  (capFinishX - capBeginX);
    int t_length =  (capFinishY - capBeginY);
 
    yield return new WaitForEndOfFrame ();
    Texture2D t = new Texture2D(t_width , t_length,TextureFormat.RGB24, true);//need     Set the image saving format correctly 
    (rect, 0, 0, false);//Read pixels according to the set area; note that the lower left corner is the origin to read    (); 
    byte[] byt = (); 
    ( +  + ".png", byt); 
 
    Sprite target =  (t, new Rect(0, 0, t_width, t_length), );
     = target;
  }

public class ScreenShot : MonoBehaviour 
{

  void OnScreenShotClick()
  {
    //Get the current system time     now = ;
    string times = ();
    //Remove the spaces before and after    times = ();
    //Replace the slash with horizontal bar    times = ("/", "-");

    string fileName = "ARScreenShot" + times + ".png";
    //Judge whether the platform is an Android platform    if ( == )
    {
      //The parameters are screen width screen height texture format whether to use mapping      Texture2D texture = new Texture2D(, , TextureFormat.RGB24, false);
      //Read the map      (new Rect(0, 0, , ), 0, 0);
      //App screenshot      ();
      //Serialize the object      byte[] bytes = ();
      //Set the path of the mobile phone folder to be stored      string destination = "/sdcard/DCIM/Screenshots";
      //If the folder does not exist      if (!(destination))
      {
        //Create this folder        (destination);
      }
      string pathSave = destination + "/" + fileName;
      (pathSave, bytes);
    }
  }
}