Rotating Sprite Around A Point Without Messing Its Drawing Point

Question

I am trying to draw and rotate an arrow sprite based on a point,around a static circle body without messing its drawing starting point. Arrow should be directed to the same direction with user touch point,static body center vector.

Let me explain it with an example.

This is how i calculate arrow drawing point:

fun powerIndicatorDownPointCalculator(playerPosition: Vector2,touchPosition: Vector2,distanceBetweenTouchPointAndPlayer:Float):Vector2{
  // player position is static body center,touch position is touch point.

    val playerPositionHolder = playerPosition.cpy()



    val abVector = playerPosition.sub(touchPosition);

    val normalizedAbVector = Vector2(abVector.x/distanceBetweenFingerAndPlayer,abVector.y/distanceBetweenFingerAndPlayer)


    Gdx.app.log("normalized ab vector",normalizedAbVector.toString())

    var pointToAddX  = 90*normalizedAbVector.x
    var pointToAddY  = 90*normalizedAbVector.y


    var newPointX  = playerPositionHolder.x + pointToAddX
    var newPointY = playerPositionHolder.y + pointToAddY
    Gdx.app.log("NEW POINT", Vector2(newPointX,newPointY).toString())

    return Vector2(newPointX,newPointY)

}

Here is a simple gif showing it:

https://i.ibb.co/TvHBMh9/MNML-November19-041320-AM.gif

This is how i calculate C point to use later on rotation(?)

 fun calculateAimingPoint(playerPosition: Vector2,touchPosition: Vector2):Vector2{
//playerPosition is staticbody center
        val abVector = playerPosition.sub(touchPosition);

        val secondPos = blackBody.position.cpy()
        val cPointPosition  = secondPos.add(abVector)
        return cPointPosition



}

This is what i wrote for rotation but for sure it is wrong since not working as i wanted:

var angle = atan2(aimingPoint.y - blackBody.position.y, aimingPoint.x - blackBody.position.x ) *180/ PI ;
//aiming point is C point, blackBody is static body
  if (angle > 90)
  {
      angle = 450 - angle;
  }
  else
  {
      angle = 90 - angle;
  }

// powerIndicator.setOrigin(????) // setOrigin is for rotation but i dont now what to write here.

  angle = angle*-1
  powerIndicator.rotation = angle.toFloat()

What i actually wanna achieve is this: https://i.ibb.co/gDM9H3L/MNML-November19-042729-AM-2.gif

Answer 1

I solved my problem guys. Trick was to set origin correctly

  var degrees = (Math.atan2((aimingPoint.x - xDownPoint).toDouble(), -(aimingPoint.y - yDownPoint).toDouble()) * 180.0 / Math.PI - 180.0f).toFloat()


            powerIndicator.setOrigin(powerIndicator.width/2,0f)

           powerIndicator.rotation = degrees