Force cancel touch?

Is there any way to make Unity cancel touch events other than when the player lifts the finger? I'm trying make it that when the player draws a line, once it reaches a certain length, the touch event will be canceled. I tried to use touchPhase.Cancelled but it does not allow me to.

You don't need to cancel touch events (which isn't possible)...just stop drawing the line, and run whatever event is necessary, when the length limit is reached.

you can have a bool value added to your code something like

//if you get the lenght between the points of the line, you wont accept an ending point update
if(somelength > lengthiwant)
   mybool = false
Vector3 EndPos;
//this means it wont draw the line nor update the ending position
//this creates the effect of your touch is not working after that lenght
if(mybool)
{
   //yourcode maybe something like this
   foreach(Touch mytouch in Input.touches)
   {
      EndPos = mytouch.position;
      Debug.DrawLine(firstPosition, EndPos, someColor);
   }
}

hope this is the answer you are looking for =)