Support Board

//Solves for y in the equation y = mx + b, we look for Y on based on the X value of the line (MidpointX) passed to us.
double CalculateY(int X1, double Y1, int X2, double Y2, double MidpointX)
{
  double
    Y = 0, //used to solve for equation of our line
    X = 0, //current bar index we are searching for
    M = 0, //slope of the line
    B = 0; //y intercept

  //We are always in Quadrant II in terms of Cartesian coordinates
  //we have to accomodate this by making our X1 and X2 values negative, now we are in Quadrant I
  X1 = -1 * X1;
  X2 = -1 * X2;

  //Calculate our slope
  //there is a possible divide by zero error here if we get to the latest bar (ArrazySize) and dont check for that condition
  if ((X2 - X1) != 0)
  {
    M = (Y2 - Y1) / (X2 - X1);
  }
  else
  {
    M = 1;
  }
  
  //must solve for b to get y intercept, equation then becomes b = Y1 - M*X1
  B = Y1 - (M*X1);

  //Print("B1 is: " + B);
  //B = Y2 - (M*X2); //double check our y intercept, B1 and B2 should be the same
  //Print("B2 is: " + B);

  //find the Y that resides on our line for the previous bar. y = mx + b
  X = -1 * MidpointX; //adjusts for Quandrant II by multiplying (-1) to MidpointX
  Y = M*X + B;
  
  //Print("MidpointX: " + X + " MidpointY is: " + NormalizeDouble(Y,5));

  return(Y);
}//end of CalculateY